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Technetium brain scanning in the diagnosis and management of cerebral abscess
Technetium Brain Scanning in the Diagnosis and Management of Cerebral Abscess
E. F. CROCKER, B. SC (Med), A. F. MCLAUGHLIN, J. G. MORRIS, R. BENN,
M.B.
M.B.
M.B.
M.B.
J. G. McLEOD, J. L. ALLSOP, Camperdown,
D. Phil (Oxon),
M.B.
M.B. New South Wales, Australia
From the Departments of Nuclear Medicine and Neurology, Royal Prince Alfred Hospital, and the Department of Medicine, Sydney University, Camperdown, New South Wales, Australia. Requests for reprints should be addressed to Dr. E. F. Cracker, Department of Nuclear Medicine, Royal Prince Alfred Hospital, Camperdown, New South Wales 2050, Australia. Manuscript accepted June 12, 1973.
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Eighteen patients with intracranial abscess were investigated over a 3 year period. Each patient was subjected to cerebral scanning with technetium-99m pertechnetate within 10 days of admission to the hospital. The scan accurately localized each lesion present. Brain scanning was found to be the most sensitive and accurate investigation in the early diagnosis and localization of intracranial abscess. When scans were performed and interpreted in careful clinical context, their accuracy approached 100 per cent. Serial scanning with the low energy, gamma emitting radiopharmaceutical technetium-99m pertechnetate was a sensitive and convenient means of monitoring the patients’ response to therapy. The brain scan abnormality in cerebral abscess is due to focal breaches in the blood brain barrier, which occur at the cellular level and which are therefore not dependant upon the presence of an accumulation of macroscopic pus of sufficient size to displace vessels or ventricles. A cerebral scan should be performed whenever cerebral abscess is suspected. In this context it should precede the diagnostically ineffective and potentially dangerous lumbar tap. With careful clinical correlation, the brain scan should reduce the present high mortality rate in patients with cerebral abscess. Early studies have suggested that the high morbidity and mortality in patients with cerebral abscess are due to a low index of clinical suspicion on initial presentation, to inaccurate localization and to the late institution of appropriate medical and surgical treatment [l-3]. Although the mortality in cerebral abscess has decreased with the introduction of more adequate antibiotics and improved surgical technics [l], it is still alarmingly high. In 1969 Garfield [3] suggested that the cerebral scan might fulfil a major role in the diagnosis and localization of cerebral abscess. His claim has more recently been emphasized by Davis and his colleague [4]. We support Garfield’s claim and
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recommend the cerebral scan as the most sensitive and accurate investigation in the diagnosis and localization of intracranial abscess, even at a stage of cerebral inflammation prior to the accumulation of macroscopic pus. MATERIAL
AND METHODS
During a 3 year period ending in February 1973, 5,000 brain scans were performed. During this time, 16 patients with intracerebral abscess and 1 patient each with extradural and subdural abscess were seen. The patients’ ages ranged from 2 months to 68 years; 14 were male, 4 were female, and 8 were infants and children. Scanning was performed by means of a rectilinear scanner (Picker 3” Magna Scanner) and a scintillation camera (Nuclear-Chicago Pho-Gamma HP 6046) from 15 minutes to 2 hours after the intravenous injection of an appropriate dose of technetium-99m pertechnetate. A minimum of four views were performed routinely: anterior, flexed posterior, and right and left lateral. All patients underwent scanning within 10 days of admission to hospital. Serial scans were performed during the acute stage of the illness to assess progress and to monitor the response to therapy. RESULTS Relevant Clinical Data (Table I). All but four patients had a recognizable predisposing cause for cerebral infection. A clinical diagnosis of intracranial abscess was made in six patients. Cerebral
TABLE I
Clinical
Age(yr) and Sex
1 2 3 4 5 6 7 8 9
3, M 4. M 6, F 2mo,M 52, M 45, F 68, M 15, M
21/2, F
10 11 12 13 14
68, M 49, M 35, M 38, M
15
65, M
16
2, M
17
3 mo, F
5wk,M
16, M
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abscess was included in the differential diagnosis of six other patients. The mortality rate was 33 per cent. The pathogen was isolated in all but two patients (Cases 11 and 15). It was cultured from aspirated pus in 14 and from the cerebrospinal fluid in 2 (Cases 13 and 17). Cerebrospinal fluid from 10 patients was examined; the protein content was raised in 9 patients and the white cell count in 6 (see Appendix). Scan Results (Table II). In every case the initial scan was abnormal. Five patients had multiple abscesses (Cases 3, 4, 10, 11 and 14). In one (Case 4), one of two lesions was missed at the time the initial scan was appraised. The scan revealed an extensive right frontal accumulation of isotope (Figure 1) which was found to be an abscess, and aspirated. The patient, however, died, and autopsy revealed an additional smaller, contiguous left frontal abscess. Reappraisal of the scans revealed that the second lesion had been apparent in the anterior view. The scan abnormality most frequently seen was a focal spherical accumulation of radioactivity (Figure 1) which, from the appearance of the scan alone, was indistinguishable from that seen in cerebral tumor. When the scan was interpreted in the context of clinical and laboratory findings, however, abscess was nominated as the most likely diagnosis in all cases. The scans of
Features
Case No.
18
BRAIN
PredisposingFactor Tetralogy of Fallot Tetralogy of Fallot Tetralogy of Fallot Proteus septicemia Lung abscess Previous neurosurgery Ples:ral empyema Nil Compound fracture right frontal bone Lung abscess Bronchiectasis Left tympanoplasty Nil Nil Chronic lymphatic leukemia Penetrating wound skull Meningitis Nil .__-. __
__--
to
Clinical Provisional Diagnosis
Final Diagnosis
Pyrexia of unknown origin Subacute bacterial endocarditis Cerebral abscess Hydrocephalus Cerebrovascular accident Pyrexia of unknown origin Cerebrovascular accident Cerebral abscess Extradural abscess
Cerebral abscess Cerebral abscess Two cerebral abscesses Two cerebral abscesses Cerebral abscess Cerebral abscess Cerebral abscess Subdural abscess Extradural abscess
Alive Alive Alive Died Died Alive Died Alive Alive
Left cerebral tumor Cerebral abscess Cerebral abscess Meningitis Partially treated meningitis with secondary hydrocephalus Chronic obstructive airways disease Cerebral abscess
Two cerebral abscesses Two cerebral abscesses Cerebral abscess Cerebral abscess Two cerebral abscesses
Died Alive Alive Died Alive
Cerebral
abscess
Died
Cerebral
abscess
Alive
Meningitis and cerebral abscess Viral encephalitis
Cerebral
abscess
Alive
Cerebral
abscess
Alive
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Outcome
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TABLE II
Central
Case No.
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posterior
parietal
Right temporal and right upper parietal “halo” Right frontal Right upper frontoparietal
6 7
Left frontal “halo” Right upper parietal
8
Right upper parietal posteriorly Right frontal Right parieto-occipital left posterior fossa Right temporoparietal “halo,” left parietooccipital
11
Left posterior temporal “halo” lesion Right temporal Left posterior parietal and right frontal Left occipitoparietal
16
Right parietal
17
Right posterior
“halo”
Left posterior temporal slow waves Right frontotemporal slow waves Right parietotemporal slow waves Diffuse slow waves Right posterior parietotemporal slow waves Left hemisphere slow waves Diffuse slow waves
...
Carotid
Diffuse Diffuse
slow waves
slow
...
... Displacement of right anterior cerebral artery to left ... Anterior cerebral arteries shifted to left with depression of posterior branches of right middle cerebral artery Displacement of right anterior cerebral artery to left
...
slow waves
... ...
...
... . 1.
.
.
.
1.
.
... Left posterior mass
parietal
Displacement of left anterior cerebral artery to right
...
...
...
Right parietal suppression and slow waves
...
parietal
Right frontal mass lesion Right parietal mass lesion .
Normal (including left vertebral artery) Right posterior parietal space occupying lesion, left-sided occipital space occupying lesion Upward bowing of left middle cerebral artery Right temporal space occupying lesion
... Left-sided
...
not well seen
...
slow waves
Left frontotemporal waves
system
Bowing of right anterior cerebral artery to left
... and
Air Study
Angiogram
ElectroencephalographicFocus
Right upper frontoparietal
9 10
ET AL.
Nervous System Investigation
Scan Abnormality Left upper
ABSCESS-CROCKER
...
Right posterior
parietal
lesion Left temporoparietal
18
NOTE: Leaders indicate
five
patients
strated
the
(Cases “doughnut”
Left-sided
slow waves
Left parietal space occupying lesion
test not performed.
3, 6, 11, 12 and 16) demon(“halo”) sign [5] (Figures
2and3).
Electroencephalography and Neuroradiologic ReElectroencephalography was sults (Table II). performed in 13 patients. All electroencephalograms were abnormal. The lesions were correctly lateralized in eight patients but were accurately localized in only three of them (Cases 3, 12 and 16). The electroencephalogram was not helpful in the diagnosis of multiple abscesses. Eleven patients were subjected to cerebral ar-
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teriography. Abscesses were correctly lateralized in eight patients but were localized in only five of them (Cases 7, 11, 12, 13 and 18). Of the six abscesses localized (one patient, Case 11, had two lesions), three were temporal, one was parietal, one was temporoparietal, and one was occipital. Four patients (Cases 4, 5, 14 and 17) had ventriculography performed. Of the five lesions present, one was not detected (one patient, Case 14, had a left parietal abscess, which was seen, and a right frontal focus of inflammation, which subsequently developed into an abscess).
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COMMENTS
Intracranial abscess remains a serious disease despite the introduction of antibiotics. Over the past two decades, the mortality has remained formidable, ranging from 35 to 65 per cent in most reported series [2,3,6]. The persistence of a high mortality and morbidity is due to a low index of clinical suspicion on presentation. Inaccurate localization and late institution of appropriate medical and surgical treatment also are important factors [3,7]. Our study supports earlier reports [2,6] that examination of the cerebrospinal fluid is of limited value in the diagnosis of brain abscess. In five patients (Cases 3. 4, 10, 12 and 14) cerebrospinal fluid findings were regarded as abnormal but nonspecific (see Appendix); only in two patients (Cases 13 and 17) did the cerebrospinal fluid yield a pathogen. The cause of death in one patient (Case 13), determined at autopsy, was compression of the brain stem following lumbar puncture. Scanning should precede the diagnostically ineffective and potentially dangerous lumbar tap in patients suspected of having a brain abscess. Early onset of focal neurologic signs or papilledema are unusual features of acute bacterial meningitis [8]. Their presence in what otherwise appears to be meningitis should prompt the investigator to consider brain abscess in the differential diagnosis. In such cases, a brain scan should precede lumbar puncture. The latter should not be performed if a focal scan abnormality is apparent.
ANTERIOR
RIGHT
LEFT
POSTERIOR
LATERAL
LATERAL
Figure 1.
Case 4. The four view brain scan revealed a large right frontal accumulation of isotope and a small left frontal abnormality (arrowed).
in Cerebral Abscess. A normal brain scan indicates that the blood brain barrier is intact [9]. This barrier prevents intravenously administered technetium-99m pertechnetate from accumulating significantly in normal brain tissue. When a disease process causes a breach to occur in this barrier, technetium accumulates in the pathologic brain tissue. Such a breach is known to occur in intracranial infection [lO,ll].
The Scan Pattern
3
1
6 Figure 2.
Case
3.
The
brain
scan
performed on admission (7-3) revealed right upper parietal and right temporal abnormalities “A” and “B,” respectively. A progress scan performed 3 weeks after admission (4-6) revealed that “B” had resolved considerably, whereas “A” was larger and exhibited the “doughnut” sign.
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LATERAL
The four view brain scan reFigure 3. Case 16. vealed a large parietal “doughnut” abnormality. The intense focus low on the rim of the “doughnut” was the site of the penetrating wound.
CASE
Anterior View
FOURTEEN -
Flexed Posterior View
SERIAL
ET AL.
The brain scan abnormality occurs with focal cerebral inflammation prior to the accumulation of macroscopic pus (Cases 3 and 14). In Case 14 (Figure 4) two scan abnormalities were seen initially. One marked abnormality occupied most of the posterior aspect of the left parietal lobe. A lesser abnormality was situated in the right frontal lobe. On aspiration, 50 ml of pus was recovered from the parietal region, but none was able to be aspirated from the frontal site. Needle biopsy of the right frontal region however revealed “small areas of hemorrhage and scanty polymorphonuclear infiltration” (Figure 5). A progress scan 1 week later revealed a diminution in the size of the left-sided lesion but an increase in the size and density of the right frontal lesion (Figure 4). Aspiration of the frontal lesion was repeated that day and IO ml of pus was removed. Case 3 demonstrates a similar situation. We have now studied a number of cases (unpublished) in which focal scan abnormalities, in patients thought to have cerebral abscess, have represented areas of “cerebritis” with histologic appearances similar to those described. Serial scans on these people have shown resolution with antibiotic therapy alone. It is, therefore, likely that early scan detection of brain abscess followed by adequate treat-
SCANS
Right Lateral View
Left Lateral View On admission Large left parietal abnormality Right frontal Craniotomy after scan
abnormality performed
Ten days following
“P”
“F”
six hours
admission
“P” decreased in size “F” increased
in size
Twenty days following Moderate resolution
admission of both
Figure 4. Pus was aspirated from the large parietal lesion soon after the initial scan. The histology (If Case 14. the needle biopsy specimen from the right frontal abnormality “F” is illustrated in Figure 5. Ten milliliters of pus were aspirated from the right frontal abscess soon after the second scan was performed.
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Figure 5. Case 14. the biopsy specimen
This section of from the right frontal lesion was stained with hematoxylin and eosin (original magnification X 240, reduced by 6 per cent). The specimen contained small areas of hemorrhage and sparse polymorphonuclear infiltration.
ment with antimicrobials could lead to resolution of such lesions without surgical intervention and thereby reduce the current high mortality. The annular “doughnut” abnormality was seen in five of our patients (Cases 3, 6, 11, 12 and 16). It is a nonspecific pattern which infers the presence of a lesion with an avascular center, and it has been described in association with cerebral tumor, abscess, infarction and subdural hematoma. In this current context it implies the presence of pus. It is of prognostic significance when first seen in a progress scan in which the initial abnormality was focal and spherical. In this situation it implies progression of the disease (Case 3, Figure 2). Electroencephalogram Localization of Intracranial A high incidence of abnormal electroAbscess. encephalograms has been reported in patients with cerebral abscess [2,3,12,13]. Electroencephalographic localization (as opposed to lateralization) of brain abscess, however, has been notoriously inaccurate. Garfield [3] concluded that the electroencephalographic localization of 53 patients subjected to electroencephalograms, even after review, was only 51 per cent accurate. More recently, Carey et al. [7] reviewed the records of 86 patients with cerebral abscess. Thirty of these were subjected to electroencephalograms. The abscess was localized in 47 per cent. Of the patients reviewed in our series, 11 had electroencephalograms performed; all were abnormal. A structural lesion was correctly lateralized in six patients, but in only three was the electroencephalogram accurate in localizing the precise anatomic site of the abscess. In no instance
did the electroencephalogram indicate the presence of multiple lesions. Neuroradiologic Technics in Localization of Intracranial Abscess (Table III). Attempts to localize brain abscess by current neuroradiologic technics have also been disappointing [2]. Abnormal neuroradiologic signs depend upon displacement of normal structures, the presence of an anomalous circulation or the presence of gas or c:alcification. None of these features may be present in a brain abscess. In addition, there are various situations in which angiography may be misleading [14]. Garfield [3] reported accurate localization of temporal lesions. Ten of the patients in our series were subjected to arteriography. In eight the abscess was lateralized, but in only four was it correctly localized. Both of the temporal lesions were localized. Angiography is thus of poor value in localizing lesions in cerebral abscess, except when the lesion is temporal. Jordan and colleagues [15] recently revived interest in the so-called “specific” angiographic appearances of cerebral abscess, in particular, the “ring sign” of Wickbom [l6]. The sign
TABLE Ill
Accuracy
of Abscess Localization
Investigation Electroencephalography Angiography Air study Scan
February 1974
Patients Subjected toTest (no.) 13 11 4 18
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denotes a “ring-like stain” seen at angiography around the abscess cavity and said to be specific for cerebral abscess, Such an appearance was not described in any of our patients. It is now generally accepted that ventriculography is an accurate means of abscess localization particularly when a parietal lobe is involved [3,7]. Four of our 18 patients were subjected to ventriculography. Each abscess was accurately localized. The right frontal focus of inflammation in one (Case 14, Figure 4), however, was not seen. Ventriculography, however, is itself a major procedure and may precipitate a crisis [3,7]. Garfield [3] concluded that complications were relatively rare but stressed that the procedure should never be undertaken lightly. Limited experience Radionuclide Localization. with early technics of radionuclide cerebral scanning has led to varying degrees of optimism in the diagnosis of cerebral abscess [17-191. Many radiopharmaceuticals have been used to localize brain abscess with a high degree of accuracy [20]. Garfield, in 1969, predicted that with the introduction of more suitable radiopharmaceuticals brain scanning would supercede neuroradiologic methods of intracranial abscess localization. Recent experience, particularly with technetium pertechnetate, supports this prediction [4,12]. Lombroso [12], reviewing the data on 13 patients with brain abscess, found over-all brain scan localization to be 86 per cent accurate. Davis [4], in reviewing 16 cases, found brain scan localization to be accurate in all. In our 18 patients, precise localization of intracranial abscess was found to be 100 per cent accurate. Each lesion was clearly defined regardless of size or location. The technetium brain scan was also accurate in demonstrating multiple abscess. In four of the five patients with multiple abscesses, all lesions were clearly seen on the initial scan appraisal. The Brain Scan as a Monitor of Response to TherThe initial scan appearance deteriorated apy* during the acute illness in five patients (Cases 1, 3, 8, 12 and 14). In four of them there was corresponding clinical deterioration (papilledema developed in one, and three became increasingly confused). The low radiation dose associated with technetium brain scanning made it possible to submit patients to serial scanning throughout the recovery period. Seven of the 12 surviving patients were followed for 12 months. The scan abnormality resolved completely in one patient (Case 3) within 3 months and partially in the other six patients (Figure 2, Case 3; Figure 4, Case 14). The
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ET AL
scan
returned
to normal
in three
patients
12 months. When a scan abnormality 12 months, it was situated peripherally niotomy site.
within
persisted at at the cra-
APPENDIX Case 1. lntracerebral Abscess (Hemophilus influenA 3 year old boy with tetralogy of Fallot was zae). admitted after a grand mal fit. He was febrile and had cyanosis, but was otherwise well. His cerebrospinal fluid contained 1 white blood cell/mm3 and 50 mg/lOO ml of protein. A brain scan obtained on admission showed slight accumulation of isotope in the left upper parietal region posteriorly. An electroencephalogram revealed a left posterior temporal focus. A repeat performed 23 days after admission, brain scan, showed that the scan abnormality had increased in size. During this time the patient’s condition remained unchanged. Angiography was technically unsatisfactory. A burr hole at the site of the brain scan abnormality revealed a large cerebral abscess. Case 2. lntracerebral Abscess (Anaerobic streptococA 4 year old boy, known to have tetralogy of cus). Fallot, was admitted after the acute onset of left hemiparesis. He was febrile, but there were no signs of raised intracranial pressure. An electroencephalogram revealed a right frontotemporal focus. A brain scan obtained on admission demonstrated an abnormal accumulation of isotope in the right frontoparietal region superiorly. Bilateral carotid angiography demonstrated bowing of the anterior cerebral arteries to the left. (Twenty milliliters of pus were aspirated from the right frontoparietal region.) Clinical response was prompt and complete, and by 6 months the scan had returned almost to normal. Case 3. lntracerebral Abscesses (Figure 2) (Anaerobic streptococcus and Bacteroides). A 6 year old girl with tetralogy of Fallot was admitted with a 3 week history of chronic movements of her right arm. She was febrile, and had mild left hemiparesis and bilateral papilledema. The cerebrospinal fluid contained 15 lymphocytes and 6 polymorphonuclear leukocytes/mm3. Protein content was 120 mg/lOO ml. A provisional diagnosis of cerebral abscess was made. A brain scan demonstrated spherical abnormalities in the right temporal and right parietal regions. These areas were surgically explored, but only a temporal abscess was found. The patient’s condition continued to deteriorate. Ventriculography 3 weeks after admission showed flattening of the roof of the right lateral ventricle only. A second brain scan at this time, revealed an increase in the size of the parietal abnormality which exhibited the “doughnut” sign (see “Comments”). The area was explored and a large abscess was found. Case 4. Multiple lntracerebral Abscesses (Proteus). A premature infant, with Proteus septicemia, presented with progressive hydrocephalus. No localizing neu-
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rologic features were present. The electroencephalogram revealed a low voltage trace with no focal features. A brain scan, performed on admission, showed a large right frontal abnormality (Figure 1). Ventriculography revealed posterior displacement of lateral ventricles and separation of the anterior horns. Forty milliliters of pus were aspirated from the right frontal region. The child responded well initially but died suddenly 3 months later. Autopsy revealed a large right frontal cerebral abscess and a smaller contiguous left frontal abscess. Case 5. lntracerebral Abscess (Anaerobic streptococcus). A 52 year old man was admitted with a 9 day history of increasing left-sided weakness and headache. He was confused, febrile and had a left hemiplegia and hemianaesthesia. The chest film revealed an opacity in the right mid zone. The electroencephalogram was suggestive of a right posterior temporoparietal structural lesion. Right common carotid arteriography revealed medial displacement of posterior branches of the anterior cerebral artery. The brain scan, performed 2 days later, revealed an area of increased isotope uptake in the superior aspect of the right frontoparietal region. Ventriculograpt-fy confirmed the presence of a right parietal mass. Exploration of this region revealed a large cerebral abscess. Despite intensive chemotherapy the patient died. Autopsy revealed an extensive cerebral abscess involving the superior aspect of the right frontal and parietal lobes. Case 6. lntracerebral Abscess (Staph. albus). A 45 year old woman presented with a ruptured anterior communicating aneurysm which was managed surgically. Hydrocephalus developed later and a ventriculoatrial shunt was inserted. A brain scan, performed postoperatively, revealed a low, mid-line, frontal abnormality consistent with surgery. Two years after initial presentation, she became febrile and a right hemiparesis developed. Brain scan showed a “doughnut” abnormality in the left frontal region parasagittally. A provisional diagnosis of cerebral abscess was made. Forty milliliters of pus were aspirated from this site. Case 7. lntracerebral Abscess (Nocardia). A 68 year old man was admitted with acute onset of left-sided weakness. He was afebrile. A chest film revealed a density in the lower lobe of the left lung. A provisional diagnosis of bronchogenic carcinoma with cerebral metastases was made. Chronic empyema was found at thoracotomy and Nocardia was isolated. The patient’s condition deteriorated postoperatively. An electroencephalogram showed no focal features, but a brain scan revealed a large spherical right upper parietal abnormality. Right common carotid arteriography demonstrated shift to the left of the anterior cerebral artery and depression of the posterior branches of the right middle cerebral artery. Surgical exploration of the site of the scan abnormality revealed a large cerebral abscess. The patient died.
Case 8. Subdural Abscess (Anaerobic streptococcus). A 15 year old boy was admitted with a 4 week history of right frontal headache and photophobia. He was febrile, exhibited marked meningismus. papilledema and left hemiparesis. Right carotid arteriography demonstrated a shift to the left of the anterior cerebral artery. Brain scan revealed an area of increased isotope uptake in the right upper parietal region posteriorly. Sixty milliliters of pus were aspirated from this subdural site. The clinical signs resolved. A repeat scan, performed 6 days postoperatively, demonstrated moderate resolution of the abnormality. Case 9. Extradural Abscess (Staph. aureus). A 2 l/2 year old girl presented 3 weeks after having sustained a right frontal compound fracture. She was febrile, drowsy and had gross right orbital cellulitis. A skull film revealed a wide fracture of the right parietal and frontal bones extending into the right orbit. The cerebrospinal fluid contained 3,450 white cells/mm3, 100 per cent polymorphonuclear leukocytes. Cerebrospinal fluid protein was 180 mg/lOO ml. A brain scan, performed soon after admission, revealed a large right frontal abnormality, which at surgery was shown to represent an extradural abscess. A 68 Case 10. lntracerebral Abscess (Nocardia). year old man presented with a 3 week history of vertigo and vomiting. He was afebrile, had a left lower motor neuron seventh nerve palsy and left-sided cerebellar signs. Papilledema was not present. A clinical diagnosis of posterior fossa tumor was made. The skull film was normal, and the electroencephalogram showed no focal features. A brain scan revealed right parietooccipital and left posterior fossa abnormalities. Four vessel arteriography performed on the following day was normal. Ten days later a right parietal burr hole was performed, and a lesion macroscopically resembling glioma was seen. No tumor cells were seen on histologic examination. The patient died postoperatively. Postmortem revealed abscess cavities in the right parietooccipital region and the left cerebellar hemisphere. In addition, there was a small abscess cavity in the apex of the right lung. Nocardia was isolated. Case 11. lntracerebral Abscess. A 40 year old man with bronchiectasis was admitted with a 6 day history of headache and progressive left-sided weakness. He was febrile, mildly confused, had papilledema and left hemiparesis. A moderate polymorphonuclear leukocytosis was present. The chest film showed an opacity in the left lower lung field. Bilateral common carotid arteriography revealed a right posterior parietal lesion. A provisional diagnosis of cerebral abscess was made. A brain scan, performed that day, confirmed the presence of this lesion and revealed a second lesion in the left parietooccipital region. A right parietal burr hole was performed, and a large abscess was found. Postoperatively, a right lower quadrantanopia developed. Vertebral angiography confirmed the presence of the
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left parietooccipital lesion, previously demonstrated on the brain scan. This abscess was also drained. The patient responded well to treatment. Case 12. Cerebral Abscess. A 35 year old man was admitted febrile and confused, 3 weeks after a left tympanoplasty. He had left-sided papilledema and nominal aphasia. The cerebrospinal fluid contained 2,000 white cells/mm3, predominantly polymorphonuclear leukocytes. Cerebrospinal fluid protein was 715 mg/lOO ml. Left-sided angiography revealed upward bowing of the left middle cerebral artery, and a scan demonstrated a spherical abnormality in the left posterior temporal region. A provisional diagnosis of cerebral abscess was made. Deterioration occurred despite vigorous antibiotic therapq. A repeat scan, 3 days later, revealed central clearing of the original abnormality. Six milliliters of pus were then drained from the site. The patient’s condition improved postoperatively, and follow-up scan revealed re’solution of the defect. Case
13.
lntracerebral Abscess (Anaerobic StreptoA 38 year old diabetic patient was admitted with a 7 day history of right retroorbital pain. He was febrile, had moderate neck stiffness and right-sided papilledema. A provisional diagnosis of meningitis was made, and the possibility of cerebral abscess was considered. The cerebrospinal fluid contained 980 predominantly polymorphonuclear white cells/mm3, leukocytes. Four days later it contained 3,000 polymorphonuclear leukocytes/mm3 and the pressure was raised. A few hours after the second lumbar puncture, left hemiparesis developed. A brain scan demonstrated a spherical abnormality in the right temporal region. Despite prompt surgical decompressiori of the right temporal abscess, the patient died. coccus).
Case
14.
Bilateral
lntracerebral
Abscess
(Esch.
coli).
A 5 week old infant presented with a bulging fontanelle while receiving Penbritinw for a nonspecific febrile illness. He was lethargic, but had no focal neurologic signs. Bilateral subdural aspirations were negative. A provisional diagnosis of partially treated meningitis with secondary hydrocephalus was made. A needle ventriculogram was suggestive of a left-sided posterior parietal lesion. A brain scan revealed left posterior parietal and right frontal abnormalities (Figure 4). Fifty milliliters of pus were aspirated from the leftsided lesion. A needle biopsy specimen from the site of the right frontal lesion revealed “brain substance with small areas of hemorrhage and sparse polymorphonuclear infiltration” (Figure 5). A repeat brain scan 1 week later revealed an increase in size of the right frontal lesion. Repeat needle aspiration of this lesion was performed and 10 ml of pus were aspirated. The patient responded well to chemotherapy, and progress scans showed resolution of both abnormalities. Case
15.
lntracerebral
with chronic
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Abscess.
leukemia
A 64 year old man was febrile and mildly
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confused on admission. He exhibited no localizing neurologic signs or evidence of raised intracranial pressure. The cerebrospinal fluid contained 2,270 white cells/mm3, 70 per cent of which were polymorphonuclear leukocytes, and cerebrospinal fluid protein was 87 mg/lOO ml. An electroencephalogram performed on admission showed left-sided slow wave preponderance. A brain scan revealed a left occipitoparietal abnormality. Left common carotid arteriography demonstrated slight mid-line shift to the right. An attempt was made to biopsy the lesion demonstrated by the scan. At craniotomy, no abnormality was found. The patieni’s condition continued to deteriorate, and he died. A postmortem examination revealed an abscess in the corpus callosum on the left side posteriorly. The surgical approach had not been sufficiently deep to reach the abscess. Case
16.
lntracerebral
Abscess
(Figure
3)
(Hemo-
A 2 year old child was admitted with a left hemiparesis 2 months after sustaining a penetrating wound to the right parietal area. He exhibited neck stiffness and bilateral papilloedema. A clinical diagnosis of cerebral abscess was made. An electroencephalogram performed on admission revealed right-sided suppression of activity with right parietal slow waves, a pattern suggestive of subdural hematoma. A brain scan revealed a large right parietal “doughnut” abnormality. One hundred and fifty milliliters of pus were aspirated from the area. philus
influenzae).
17. lntracerebral Abscess (Esch. Coli). A 2 month old child was admitted after having had a grand mal fit. She was febrile, drowsy and tended not to move her left arm. There was no evidence of raised intracranial pressure. Cerebrospinal fluid contained predominantly polymorphonu2,200 white celIs/mm3, clear leukocytes, and 1,000 mg/ml of protein. Esch. coli was cultured from the cerebrospinal fluid. Ventriculography revealed a lesion in the right posterior parietal region. A brain scan showed a right posterior parietal abnormality. Pus was aspirated from this site. Clinical response was excellent, and the scan abnormality resolved. Case
Case 18. lntracerebral Abscess (Staph. albus). A 16 year old boy was admitted febrile with rapidly evolving right hemiplegia. His cerebrospinal fluid contained 320 white cells/mm3, 95 per cent of which were polymorphonuclear leukocytes. Protein was 120 mg/lOO ml. An electroencephalogram revealed left hemisphere slow wave activity. A brain scan demonstrated an extensive left temporoparietal abnormality. Arteriography was suggestive of a lesion occupying the left parietal space. A left temporoparietal abscess was found at operation. ACKNOWLEDGMENT wish to thank retarial assistance.
We
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Miss
Nicolette
Cato for her sec-
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REFERENCES
6. 7. a. 9. 10.
11
Jooma OV, Pennybacker JB, Tulton GK: Brain abscess: aspiration, drainage or excision. J Neurol’Neurosurg and Psychiat 14: 308, 1951. Gregory DH, Hessner R, Zinneman HH: Metastatic brain abscess. Arch Int Med 119: 25, 1967. Garfield J: Management of supratentoral intracranial abscess. A review of 200 cases. Br Med J 2: 7. 1969. Davis DQ, Potchen EJ: Brain scanning and intracranial inflammatory disease. Radiology 95: 345, 1970. O’Mara RE. McAfee JG, Chodos RB: The “douohnut” sign in cerebral radioisotopic images. Radiology 72: 581. 1967. Ballantine HT Jr, White JC: Brain abscess. N. Engl J Med 248: 14, 1953. Carey ME, Chou SN, French LA: Experience with brain abscesses. J Neurosurg 36: 1, 1972. Dodge PR, Swartz MN: Bacterial meningitis. A review of selected aspects. N Engl J Med 272: 954, 1965. Blahd WH: Nuclear Medicine, New York, McGraw-Hill Book Co., inc., 1971. Lithander A, Lithander B: The passage of benzyl penicillin in the cerebrospinal fluid after administration in haemophilus influenzae meningitis. Acta Pathol Microbiol Stand 67: 569, 1966. Lithander A: The passage of parenteral ampicillin into the cerebrospinal fluid in haemophilus influenzae meningitis. Acta Pathol Microbial Stand 64: 329, 1965.
12.
13.
14. 15.
16. 17.
18.
19.
20.
February 1974
Lombroso
CT, Erba G, Yogd T. Logowitz
N, St. Hilaire J:
Two dimensional sonar scanning for detection of intracranial lesions. Arch Neurol 23: 518. 1970. Heineman HS, Braude Al. Osterholm JL: Intracranial supporative disease. Early presumption diagnosis and successful therapy without surgery. JAMA 218: 1542, 1971. Bligh AS, Rack PMH: Carotid angiography and cerebral abscess. J Neurosurg 19: 482, 1962. Jordan CE, James AE, Hodges FJ: Comparison of the cerebral angiogramme and the brain radionuclide image in brain abscess. Radiology 104: 327, 1972. Wickbom I: Angiography of the carotid artery. Acta Radiol (suppl) 72: 1948. Tefft M, Matson DD, Neuhauswer EBD: Brain abscess in children. Radiologic methods for early recognition. Am J Roentgen01 Radium Ther Nucl Med 98: 675, 1966. Sweet WH. Mealey J, Aronow S, Brownwell GL: Localization of focal intracranial lesions by scanning of rays from position emitting isotopes. Clin Neurosurg 7: 159, 1961. Overton MC, Haynie TP, Snodgrass SR: ‘Brain scans in non-neoplastic intracranial lesions. JAMA 191: 431. 1965. Van Eck JHM: Clinical value of isotope encephalography. J Neurosurg Psychiatry 29: 145, 1966.
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E. F. CROCKER, B. SC (Med), A. F. MCLAUGHLIN, J. G. MORRIS, R. BENN,
M.B.
M.B.
M.B.
M.B.
J. G. McLEOD, J. L. ALLSOP, Camperdown,
D. Phil (Oxon),
M.B.
M.B. New South Wales, Australia
From the Departments of Nuclear Medicine and Neurology, Royal Prince Alfred Hospital, and the Department of Medicine, Sydney University, Camperdown, New South Wales, Australia. Requests for reprints should be addressed to Dr. E. F. Cracker, Department of Nuclear Medicine, Royal Prince Alfred Hospital, Camperdown, New South Wales 2050, Australia. Manuscript accepted June 12, 1973.
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Eighteen patients with intracranial abscess were investigated over a 3 year period. Each patient was subjected to cerebral scanning with technetium-99m pertechnetate within 10 days of admission to the hospital. The scan accurately localized each lesion present. Brain scanning was found to be the most sensitive and accurate investigation in the early diagnosis and localization of intracranial abscess. When scans were performed and interpreted in careful clinical context, their accuracy approached 100 per cent. Serial scanning with the low energy, gamma emitting radiopharmaceutical technetium-99m pertechnetate was a sensitive and convenient means of monitoring the patients’ response to therapy. The brain scan abnormality in cerebral abscess is due to focal breaches in the blood brain barrier, which occur at the cellular level and which are therefore not dependant upon the presence of an accumulation of macroscopic pus of sufficient size to displace vessels or ventricles. A cerebral scan should be performed whenever cerebral abscess is suspected. In this context it should precede the diagnostically ineffective and potentially dangerous lumbar tap. With careful clinical correlation, the brain scan should reduce the present high mortality rate in patients with cerebral abscess. Early studies have suggested that the high morbidity and mortality in patients with cerebral abscess are due to a low index of clinical suspicion on initial presentation, to inaccurate localization and to the late institution of appropriate medical and surgical treatment [l-3]. Although the mortality in cerebral abscess has decreased with the introduction of more adequate antibiotics and improved surgical technics [l], it is still alarmingly high. In 1969 Garfield [3] suggested that the cerebral scan might fulfil a major role in the diagnosis and localization of cerebral abscess. His claim has more recently been emphasized by Davis and his colleague [4]. We support Garfield’s claim and
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recommend the cerebral scan as the most sensitive and accurate investigation in the diagnosis and localization of intracranial abscess, even at a stage of cerebral inflammation prior to the accumulation of macroscopic pus. MATERIAL
AND METHODS
During a 3 year period ending in February 1973, 5,000 brain scans were performed. During this time, 16 patients with intracerebral abscess and 1 patient each with extradural and subdural abscess were seen. The patients’ ages ranged from 2 months to 68 years; 14 were male, 4 were female, and 8 were infants and children. Scanning was performed by means of a rectilinear scanner (Picker 3” Magna Scanner) and a scintillation camera (Nuclear-Chicago Pho-Gamma HP 6046) from 15 minutes to 2 hours after the intravenous injection of an appropriate dose of technetium-99m pertechnetate. A minimum of four views were performed routinely: anterior, flexed posterior, and right and left lateral. All patients underwent scanning within 10 days of admission to hospital. Serial scans were performed during the acute stage of the illness to assess progress and to monitor the response to therapy. RESULTS Relevant Clinical Data (Table I). All but four patients had a recognizable predisposing cause for cerebral infection. A clinical diagnosis of intracranial abscess was made in six patients. Cerebral
TABLE I
Clinical
Age(yr) and Sex
1 2 3 4 5 6 7 8 9
3, M 4. M 6, F 2mo,M 52, M 45, F 68, M 15, M
21/2, F
10 11 12 13 14
68, M 49, M 35, M 38, M
15
65, M
16
2, M
17
3 mo, F
5wk,M
16, M
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abscess was included in the differential diagnosis of six other patients. The mortality rate was 33 per cent. The pathogen was isolated in all but two patients (Cases 11 and 15). It was cultured from aspirated pus in 14 and from the cerebrospinal fluid in 2 (Cases 13 and 17). Cerebrospinal fluid from 10 patients was examined; the protein content was raised in 9 patients and the white cell count in 6 (see Appendix). Scan Results (Table II). In every case the initial scan was abnormal. Five patients had multiple abscesses (Cases 3, 4, 10, 11 and 14). In one (Case 4), one of two lesions was missed at the time the initial scan was appraised. The scan revealed an extensive right frontal accumulation of isotope (Figure 1) which was found to be an abscess, and aspirated. The patient, however, died, and autopsy revealed an additional smaller, contiguous left frontal abscess. Reappraisal of the scans revealed that the second lesion had been apparent in the anterior view. The scan abnormality most frequently seen was a focal spherical accumulation of radioactivity (Figure 1) which, from the appearance of the scan alone, was indistinguishable from that seen in cerebral tumor. When the scan was interpreted in the context of clinical and laboratory findings, however, abscess was nominated as the most likely diagnosis in all cases. The scans of
Features
Case No.
18
BRAIN
PredisposingFactor Tetralogy of Fallot Tetralogy of Fallot Tetralogy of Fallot Proteus septicemia Lung abscess Previous neurosurgery Ples:ral empyema Nil Compound fracture right frontal bone Lung abscess Bronchiectasis Left tympanoplasty Nil Nil Chronic lymphatic leukemia Penetrating wound skull Meningitis Nil .__-. __
__--
to
Clinical Provisional Diagnosis
Final Diagnosis
Pyrexia of unknown origin Subacute bacterial endocarditis Cerebral abscess Hydrocephalus Cerebrovascular accident Pyrexia of unknown origin Cerebrovascular accident Cerebral abscess Extradural abscess
Cerebral abscess Cerebral abscess Two cerebral abscesses Two cerebral abscesses Cerebral abscess Cerebral abscess Cerebral abscess Subdural abscess Extradural abscess
Alive Alive Alive Died Died Alive Died Alive Alive
Left cerebral tumor Cerebral abscess Cerebral abscess Meningitis Partially treated meningitis with secondary hydrocephalus Chronic obstructive airways disease Cerebral abscess
Two cerebral abscesses Two cerebral abscesses Cerebral abscess Cerebral abscess Two cerebral abscesses
Died Alive Alive Died Alive
Cerebral
abscess
Died
Cerebral
abscess
Alive
Meningitis and cerebral abscess Viral encephalitis
Cerebral
abscess
Alive
Cerebral
abscess
Alive
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TABLE II
Central
Case No.
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posterior
parietal
Right temporal and right upper parietal “halo” Right frontal Right upper frontoparietal
6 7
Left frontal “halo” Right upper parietal
8
Right upper parietal posteriorly Right frontal Right parieto-occipital left posterior fossa Right temporoparietal “halo,” left parietooccipital
11
Left posterior temporal “halo” lesion Right temporal Left posterior parietal and right frontal Left occipitoparietal
16
Right parietal
17
Right posterior
“halo”
Left posterior temporal slow waves Right frontotemporal slow waves Right parietotemporal slow waves Diffuse slow waves Right posterior parietotemporal slow waves Left hemisphere slow waves Diffuse slow waves
...
Carotid
Diffuse Diffuse
slow waves
slow
...
... Displacement of right anterior cerebral artery to left ... Anterior cerebral arteries shifted to left with depression of posterior branches of right middle cerebral artery Displacement of right anterior cerebral artery to left
...
slow waves
... ...
...
... . 1.
.
.
.
1.
.
... Left posterior mass
parietal
Displacement of left anterior cerebral artery to right
...
...
...
Right parietal suppression and slow waves
...
parietal
Right frontal mass lesion Right parietal mass lesion .
Normal (including left vertebral artery) Right posterior parietal space occupying lesion, left-sided occipital space occupying lesion Upward bowing of left middle cerebral artery Right temporal space occupying lesion
... Left-sided
...
not well seen
...
slow waves
Left frontotemporal waves
system
Bowing of right anterior cerebral artery to left
... and
Air Study
Angiogram
ElectroencephalographicFocus
Right upper frontoparietal
9 10
ET AL.
Nervous System Investigation
Scan Abnormality Left upper
ABSCESS-CROCKER
...
Right posterior
parietal
lesion Left temporoparietal
18
NOTE: Leaders indicate
five
patients
strated
the
(Cases “doughnut”
Left-sided
slow waves
Left parietal space occupying lesion
test not performed.
3, 6, 11, 12 and 16) demon(“halo”) sign [5] (Figures
2and3).
Electroencephalography and Neuroradiologic ReElectroencephalography was sults (Table II). performed in 13 patients. All electroencephalograms were abnormal. The lesions were correctly lateralized in eight patients but were accurately localized in only three of them (Cases 3, 12 and 16). The electroencephalogram was not helpful in the diagnosis of multiple abscesses. Eleven patients were subjected to cerebral ar-
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teriography. Abscesses were correctly lateralized in eight patients but were localized in only five of them (Cases 7, 11, 12, 13 and 18). Of the six abscesses localized (one patient, Case 11, had two lesions), three were temporal, one was parietal, one was temporoparietal, and one was occipital. Four patients (Cases 4, 5, 14 and 17) had ventriculography performed. Of the five lesions present, one was not detected (one patient, Case 14, had a left parietal abscess, which was seen, and a right frontal focus of inflammation, which subsequently developed into an abscess).
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COMMENTS
Intracranial abscess remains a serious disease despite the introduction of antibiotics. Over the past two decades, the mortality has remained formidable, ranging from 35 to 65 per cent in most reported series [2,3,6]. The persistence of a high mortality and morbidity is due to a low index of clinical suspicion on presentation. Inaccurate localization and late institution of appropriate medical and surgical treatment also are important factors [3,7]. Our study supports earlier reports [2,6] that examination of the cerebrospinal fluid is of limited value in the diagnosis of brain abscess. In five patients (Cases 3. 4, 10, 12 and 14) cerebrospinal fluid findings were regarded as abnormal but nonspecific (see Appendix); only in two patients (Cases 13 and 17) did the cerebrospinal fluid yield a pathogen. The cause of death in one patient (Case 13), determined at autopsy, was compression of the brain stem following lumbar puncture. Scanning should precede the diagnostically ineffective and potentially dangerous lumbar tap in patients suspected of having a brain abscess. Early onset of focal neurologic signs or papilledema are unusual features of acute bacterial meningitis [8]. Their presence in what otherwise appears to be meningitis should prompt the investigator to consider brain abscess in the differential diagnosis. In such cases, a brain scan should precede lumbar puncture. The latter should not be performed if a focal scan abnormality is apparent.
ANTERIOR
RIGHT
LEFT
POSTERIOR
LATERAL
LATERAL
Figure 1.
Case 4. The four view brain scan revealed a large right frontal accumulation of isotope and a small left frontal abnormality (arrowed).
in Cerebral Abscess. A normal brain scan indicates that the blood brain barrier is intact [9]. This barrier prevents intravenously administered technetium-99m pertechnetate from accumulating significantly in normal brain tissue. When a disease process causes a breach to occur in this barrier, technetium accumulates in the pathologic brain tissue. Such a breach is known to occur in intracranial infection [lO,ll].
The Scan Pattern
3
1
6 Figure 2.
Case
3.
The
brain
scan
performed on admission (7-3) revealed right upper parietal and right temporal abnormalities “A” and “B,” respectively. A progress scan performed 3 weeks after admission (4-6) revealed that “B” had resolved considerably, whereas “A” was larger and exhibited the “doughnut” sign.
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LATERAL
The four view brain scan reFigure 3. Case 16. vealed a large parietal “doughnut” abnormality. The intense focus low on the rim of the “doughnut” was the site of the penetrating wound.
CASE
Anterior View
FOURTEEN -
Flexed Posterior View
SERIAL
ET AL.
The brain scan abnormality occurs with focal cerebral inflammation prior to the accumulation of macroscopic pus (Cases 3 and 14). In Case 14 (Figure 4) two scan abnormalities were seen initially. One marked abnormality occupied most of the posterior aspect of the left parietal lobe. A lesser abnormality was situated in the right frontal lobe. On aspiration, 50 ml of pus was recovered from the parietal region, but none was able to be aspirated from the frontal site. Needle biopsy of the right frontal region however revealed “small areas of hemorrhage and scanty polymorphonuclear infiltration” (Figure 5). A progress scan 1 week later revealed a diminution in the size of the left-sided lesion but an increase in the size and density of the right frontal lesion (Figure 4). Aspiration of the frontal lesion was repeated that day and IO ml of pus was removed. Case 3 demonstrates a similar situation. We have now studied a number of cases (unpublished) in which focal scan abnormalities, in patients thought to have cerebral abscess, have represented areas of “cerebritis” with histologic appearances similar to those described. Serial scans on these people have shown resolution with antibiotic therapy alone. It is, therefore, likely that early scan detection of brain abscess followed by adequate treat-
SCANS
Right Lateral View
Left Lateral View On admission Large left parietal abnormality Right frontal Craniotomy after scan
abnormality performed
Ten days following
“P”
“F”
six hours
admission
“P” decreased in size “F” increased
in size
Twenty days following Moderate resolution
admission of both
Figure 4. Pus was aspirated from the large parietal lesion soon after the initial scan. The histology (If Case 14. the needle biopsy specimen from the right frontal abnormality “F” is illustrated in Figure 5. Ten milliliters of pus were aspirated from the right frontal abscess soon after the second scan was performed.
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Figure 5. Case 14. the biopsy specimen
This section of from the right frontal lesion was stained with hematoxylin and eosin (original magnification X 240, reduced by 6 per cent). The specimen contained small areas of hemorrhage and sparse polymorphonuclear infiltration.
ment with antimicrobials could lead to resolution of such lesions without surgical intervention and thereby reduce the current high mortality. The annular “doughnut” abnormality was seen in five of our patients (Cases 3, 6, 11, 12 and 16). It is a nonspecific pattern which infers the presence of a lesion with an avascular center, and it has been described in association with cerebral tumor, abscess, infarction and subdural hematoma. In this current context it implies the presence of pus. It is of prognostic significance when first seen in a progress scan in which the initial abnormality was focal and spherical. In this situation it implies progression of the disease (Case 3, Figure 2). Electroencephalogram Localization of Intracranial A high incidence of abnormal electroAbscess. encephalograms has been reported in patients with cerebral abscess [2,3,12,13]. Electroencephalographic localization (as opposed to lateralization) of brain abscess, however, has been notoriously inaccurate. Garfield [3] concluded that the electroencephalographic localization of 53 patients subjected to electroencephalograms, even after review, was only 51 per cent accurate. More recently, Carey et al. [7] reviewed the records of 86 patients with cerebral abscess. Thirty of these were subjected to electroencephalograms. The abscess was localized in 47 per cent. Of the patients reviewed in our series, 11 had electroencephalograms performed; all were abnormal. A structural lesion was correctly lateralized in six patients, but in only three was the electroencephalogram accurate in localizing the precise anatomic site of the abscess. In no instance
did the electroencephalogram indicate the presence of multiple lesions. Neuroradiologic Technics in Localization of Intracranial Abscess (Table III). Attempts to localize brain abscess by current neuroradiologic technics have also been disappointing [2]. Abnormal neuroradiologic signs depend upon displacement of normal structures, the presence of an anomalous circulation or the presence of gas or c:alcification. None of these features may be present in a brain abscess. In addition, there are various situations in which angiography may be misleading [14]. Garfield [3] reported accurate localization of temporal lesions. Ten of the patients in our series were subjected to arteriography. In eight the abscess was lateralized, but in only four was it correctly localized. Both of the temporal lesions were localized. Angiography is thus of poor value in localizing lesions in cerebral abscess, except when the lesion is temporal. Jordan and colleagues [15] recently revived interest in the so-called “specific” angiographic appearances of cerebral abscess, in particular, the “ring sign” of Wickbom [l6]. The sign
TABLE Ill
Accuracy
of Abscess Localization
Investigation Electroencephalography Angiography Air study Scan
February 1974
Patients Subjected toTest (no.) 13 11 4 18
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denotes a “ring-like stain” seen at angiography around the abscess cavity and said to be specific for cerebral abscess, Such an appearance was not described in any of our patients. It is now generally accepted that ventriculography is an accurate means of abscess localization particularly when a parietal lobe is involved [3,7]. Four of our 18 patients were subjected to ventriculography. Each abscess was accurately localized. The right frontal focus of inflammation in one (Case 14, Figure 4), however, was not seen. Ventriculography, however, is itself a major procedure and may precipitate a crisis [3,7]. Garfield [3] concluded that complications were relatively rare but stressed that the procedure should never be undertaken lightly. Limited experience Radionuclide Localization. with early technics of radionuclide cerebral scanning has led to varying degrees of optimism in the diagnosis of cerebral abscess [17-191. Many radiopharmaceuticals have been used to localize brain abscess with a high degree of accuracy [20]. Garfield, in 1969, predicted that with the introduction of more suitable radiopharmaceuticals brain scanning would supercede neuroradiologic methods of intracranial abscess localization. Recent experience, particularly with technetium pertechnetate, supports this prediction [4,12]. Lombroso [12], reviewing the data on 13 patients with brain abscess, found over-all brain scan localization to be 86 per cent accurate. Davis [4], in reviewing 16 cases, found brain scan localization to be accurate in all. In our 18 patients, precise localization of intracranial abscess was found to be 100 per cent accurate. Each lesion was clearly defined regardless of size or location. The technetium brain scan was also accurate in demonstrating multiple abscess. In four of the five patients with multiple abscesses, all lesions were clearly seen on the initial scan appraisal. The Brain Scan as a Monitor of Response to TherThe initial scan appearance deteriorated apy* during the acute illness in five patients (Cases 1, 3, 8, 12 and 14). In four of them there was corresponding clinical deterioration (papilledema developed in one, and three became increasingly confused). The low radiation dose associated with technetium brain scanning made it possible to submit patients to serial scanning throughout the recovery period. Seven of the 12 surviving patients were followed for 12 months. The scan abnormality resolved completely in one patient (Case 3) within 3 months and partially in the other six patients (Figure 2, Case 3; Figure 4, Case 14). The
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ET AL
scan
returned
to normal
in three
patients
12 months. When a scan abnormality 12 months, it was situated peripherally niotomy site.
within
persisted at at the cra-
APPENDIX Case 1. lntracerebral Abscess (Hemophilus influenA 3 year old boy with tetralogy of Fallot was zae). admitted after a grand mal fit. He was febrile and had cyanosis, but was otherwise well. His cerebrospinal fluid contained 1 white blood cell/mm3 and 50 mg/lOO ml of protein. A brain scan obtained on admission showed slight accumulation of isotope in the left upper parietal region posteriorly. An electroencephalogram revealed a left posterior temporal focus. A repeat performed 23 days after admission, brain scan, showed that the scan abnormality had increased in size. During this time the patient’s condition remained unchanged. Angiography was technically unsatisfactory. A burr hole at the site of the brain scan abnormality revealed a large cerebral abscess. Case 2. lntracerebral Abscess (Anaerobic streptococA 4 year old boy, known to have tetralogy of cus). Fallot, was admitted after the acute onset of left hemiparesis. He was febrile, but there were no signs of raised intracranial pressure. An electroencephalogram revealed a right frontotemporal focus. A brain scan obtained on admission demonstrated an abnormal accumulation of isotope in the right frontoparietal region superiorly. Bilateral carotid angiography demonstrated bowing of the anterior cerebral arteries to the left. (Twenty milliliters of pus were aspirated from the right frontoparietal region.) Clinical response was prompt and complete, and by 6 months the scan had returned almost to normal. Case 3. lntracerebral Abscesses (Figure 2) (Anaerobic streptococcus and Bacteroides). A 6 year old girl with tetralogy of Fallot was admitted with a 3 week history of chronic movements of her right arm. She was febrile, and had mild left hemiparesis and bilateral papilledema. The cerebrospinal fluid contained 15 lymphocytes and 6 polymorphonuclear leukocytes/mm3. Protein content was 120 mg/lOO ml. A provisional diagnosis of cerebral abscess was made. A brain scan demonstrated spherical abnormalities in the right temporal and right parietal regions. These areas were surgically explored, but only a temporal abscess was found. The patient’s condition continued to deteriorate. Ventriculography 3 weeks after admission showed flattening of the roof of the right lateral ventricle only. A second brain scan at this time, revealed an increase in the size of the parietal abnormality which exhibited the “doughnut” sign (see “Comments”). The area was explored and a large abscess was found. Case 4. Multiple lntracerebral Abscesses (Proteus). A premature infant, with Proteus septicemia, presented with progressive hydrocephalus. No localizing neu-
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rologic features were present. The electroencephalogram revealed a low voltage trace with no focal features. A brain scan, performed on admission, showed a large right frontal abnormality (Figure 1). Ventriculography revealed posterior displacement of lateral ventricles and separation of the anterior horns. Forty milliliters of pus were aspirated from the right frontal region. The child responded well initially but died suddenly 3 months later. Autopsy revealed a large right frontal cerebral abscess and a smaller contiguous left frontal abscess. Case 5. lntracerebral Abscess (Anaerobic streptococcus). A 52 year old man was admitted with a 9 day history of increasing left-sided weakness and headache. He was confused, febrile and had a left hemiplegia and hemianaesthesia. The chest film revealed an opacity in the right mid zone. The electroencephalogram was suggestive of a right posterior temporoparietal structural lesion. Right common carotid arteriography revealed medial displacement of posterior branches of the anterior cerebral artery. The brain scan, performed 2 days later, revealed an area of increased isotope uptake in the superior aspect of the right frontoparietal region. Ventriculograpt-fy confirmed the presence of a right parietal mass. Exploration of this region revealed a large cerebral abscess. Despite intensive chemotherapy the patient died. Autopsy revealed an extensive cerebral abscess involving the superior aspect of the right frontal and parietal lobes. Case 6. lntracerebral Abscess (Staph. albus). A 45 year old woman presented with a ruptured anterior communicating aneurysm which was managed surgically. Hydrocephalus developed later and a ventriculoatrial shunt was inserted. A brain scan, performed postoperatively, revealed a low, mid-line, frontal abnormality consistent with surgery. Two years after initial presentation, she became febrile and a right hemiparesis developed. Brain scan showed a “doughnut” abnormality in the left frontal region parasagittally. A provisional diagnosis of cerebral abscess was made. Forty milliliters of pus were aspirated from this site. Case 7. lntracerebral Abscess (Nocardia). A 68 year old man was admitted with acute onset of left-sided weakness. He was afebrile. A chest film revealed a density in the lower lobe of the left lung. A provisional diagnosis of bronchogenic carcinoma with cerebral metastases was made. Chronic empyema was found at thoracotomy and Nocardia was isolated. The patient’s condition deteriorated postoperatively. An electroencephalogram showed no focal features, but a brain scan revealed a large spherical right upper parietal abnormality. Right common carotid arteriography demonstrated shift to the left of the anterior cerebral artery and depression of the posterior branches of the right middle cerebral artery. Surgical exploration of the site of the scan abnormality revealed a large cerebral abscess. The patient died.
Case 8. Subdural Abscess (Anaerobic streptococcus). A 15 year old boy was admitted with a 4 week history of right frontal headache and photophobia. He was febrile, exhibited marked meningismus. papilledema and left hemiparesis. Right carotid arteriography demonstrated a shift to the left of the anterior cerebral artery. Brain scan revealed an area of increased isotope uptake in the right upper parietal region posteriorly. Sixty milliliters of pus were aspirated from this subdural site. The clinical signs resolved. A repeat scan, performed 6 days postoperatively, demonstrated moderate resolution of the abnormality. Case 9. Extradural Abscess (Staph. aureus). A 2 l/2 year old girl presented 3 weeks after having sustained a right frontal compound fracture. She was febrile, drowsy and had gross right orbital cellulitis. A skull film revealed a wide fracture of the right parietal and frontal bones extending into the right orbit. The cerebrospinal fluid contained 3,450 white cells/mm3, 100 per cent polymorphonuclear leukocytes. Cerebrospinal fluid protein was 180 mg/lOO ml. A brain scan, performed soon after admission, revealed a large right frontal abnormality, which at surgery was shown to represent an extradural abscess. A 68 Case 10. lntracerebral Abscess (Nocardia). year old man presented with a 3 week history of vertigo and vomiting. He was afebrile, had a left lower motor neuron seventh nerve palsy and left-sided cerebellar signs. Papilledema was not present. A clinical diagnosis of posterior fossa tumor was made. The skull film was normal, and the electroencephalogram showed no focal features. A brain scan revealed right parietooccipital and left posterior fossa abnormalities. Four vessel arteriography performed on the following day was normal. Ten days later a right parietal burr hole was performed, and a lesion macroscopically resembling glioma was seen. No tumor cells were seen on histologic examination. The patient died postoperatively. Postmortem revealed abscess cavities in the right parietooccipital region and the left cerebellar hemisphere. In addition, there was a small abscess cavity in the apex of the right lung. Nocardia was isolated. Case 11. lntracerebral Abscess. A 40 year old man with bronchiectasis was admitted with a 6 day history of headache and progressive left-sided weakness. He was febrile, mildly confused, had papilledema and left hemiparesis. A moderate polymorphonuclear leukocytosis was present. The chest film showed an opacity in the left lower lung field. Bilateral common carotid arteriography revealed a right posterior parietal lesion. A provisional diagnosis of cerebral abscess was made. A brain scan, performed that day, confirmed the presence of this lesion and revealed a second lesion in the left parietooccipital region. A right parietal burr hole was performed, and a large abscess was found. Postoperatively, a right lower quadrantanopia developed. Vertebral angiography confirmed the presence of the
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left parietooccipital lesion, previously demonstrated on the brain scan. This abscess was also drained. The patient responded well to treatment. Case 12. Cerebral Abscess. A 35 year old man was admitted febrile and confused, 3 weeks after a left tympanoplasty. He had left-sided papilledema and nominal aphasia. The cerebrospinal fluid contained 2,000 white cells/mm3, predominantly polymorphonuclear leukocytes. Cerebrospinal fluid protein was 715 mg/lOO ml. Left-sided angiography revealed upward bowing of the left middle cerebral artery, and a scan demonstrated a spherical abnormality in the left posterior temporal region. A provisional diagnosis of cerebral abscess was made. Deterioration occurred despite vigorous antibiotic therapq. A repeat scan, 3 days later, revealed central clearing of the original abnormality. Six milliliters of pus were then drained from the site. The patient’s condition improved postoperatively, and follow-up scan revealed re’solution of the defect. Case
13.
lntracerebral Abscess (Anaerobic StreptoA 38 year old diabetic patient was admitted with a 7 day history of right retroorbital pain. He was febrile, had moderate neck stiffness and right-sided papilledema. A provisional diagnosis of meningitis was made, and the possibility of cerebral abscess was considered. The cerebrospinal fluid contained 980 predominantly polymorphonuclear white cells/mm3, leukocytes. Four days later it contained 3,000 polymorphonuclear leukocytes/mm3 and the pressure was raised. A few hours after the second lumbar puncture, left hemiparesis developed. A brain scan demonstrated a spherical abnormality in the right temporal region. Despite prompt surgical decompressiori of the right temporal abscess, the patient died. coccus).
Case
14.
Bilateral
lntracerebral
Abscess
(Esch.
coli).
A 5 week old infant presented with a bulging fontanelle while receiving Penbritinw for a nonspecific febrile illness. He was lethargic, but had no focal neurologic signs. Bilateral subdural aspirations were negative. A provisional diagnosis of partially treated meningitis with secondary hydrocephalus was made. A needle ventriculogram was suggestive of a left-sided posterior parietal lesion. A brain scan revealed left posterior parietal and right frontal abnormalities (Figure 4). Fifty milliliters of pus were aspirated from the leftsided lesion. A needle biopsy specimen from the site of the right frontal lesion revealed “brain substance with small areas of hemorrhage and sparse polymorphonuclear infiltration” (Figure 5). A repeat brain scan 1 week later revealed an increase in size of the right frontal lesion. Repeat needle aspiration of this lesion was performed and 10 ml of pus were aspirated. The patient responded well to chemotherapy, and progress scans showed resolution of both abnormalities. Case
15.
lntracerebral
with chronic
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February 1974
Abscess.
leukemia
A 64 year old man was febrile and mildly
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confused on admission. He exhibited no localizing neurologic signs or evidence of raised intracranial pressure. The cerebrospinal fluid contained 2,270 white cells/mm3, 70 per cent of which were polymorphonuclear leukocytes, and cerebrospinal fluid protein was 87 mg/lOO ml. An electroencephalogram performed on admission showed left-sided slow wave preponderance. A brain scan revealed a left occipitoparietal abnormality. Left common carotid arteriography demonstrated slight mid-line shift to the right. An attempt was made to biopsy the lesion demonstrated by the scan. At craniotomy, no abnormality was found. The patieni’s condition continued to deteriorate, and he died. A postmortem examination revealed an abscess in the corpus callosum on the left side posteriorly. The surgical approach had not been sufficiently deep to reach the abscess. Case
16.
lntracerebral
Abscess
(Figure
3)
(Hemo-
A 2 year old child was admitted with a left hemiparesis 2 months after sustaining a penetrating wound to the right parietal area. He exhibited neck stiffness and bilateral papilloedema. A clinical diagnosis of cerebral abscess was made. An electroencephalogram performed on admission revealed right-sided suppression of activity with right parietal slow waves, a pattern suggestive of subdural hematoma. A brain scan revealed a large right parietal “doughnut” abnormality. One hundred and fifty milliliters of pus were aspirated from the area. philus
influenzae).
17. lntracerebral Abscess (Esch. Coli). A 2 month old child was admitted after having had a grand mal fit. She was febrile, drowsy and tended not to move her left arm. There was no evidence of raised intracranial pressure. Cerebrospinal fluid contained predominantly polymorphonu2,200 white celIs/mm3, clear leukocytes, and 1,000 mg/ml of protein. Esch. coli was cultured from the cerebrospinal fluid. Ventriculography revealed a lesion in the right posterior parietal region. A brain scan showed a right posterior parietal abnormality. Pus was aspirated from this site. Clinical response was excellent, and the scan abnormality resolved. Case
Case 18. lntracerebral Abscess (Staph. albus). A 16 year old boy was admitted febrile with rapidly evolving right hemiplegia. His cerebrospinal fluid contained 320 white cells/mm3, 95 per cent of which were polymorphonuclear leukocytes. Protein was 120 mg/lOO ml. An electroencephalogram revealed left hemisphere slow wave activity. A brain scan demonstrated an extensive left temporoparietal abnormality. Arteriography was suggestive of a lesion occupying the left parietal space. A left temporoparietal abscess was found at operation. ACKNOWLEDGMENT wish to thank retarial assistance.
We
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Nicolette
Cato for her sec-
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REFERENCES
6. 7. a. 9. 10.
11
Jooma OV, Pennybacker JB, Tulton GK: Brain abscess: aspiration, drainage or excision. J Neurol’Neurosurg and Psychiat 14: 308, 1951. Gregory DH, Hessner R, Zinneman HH: Metastatic brain abscess. Arch Int Med 119: 25, 1967. Garfield J: Management of supratentoral intracranial abscess. A review of 200 cases. Br Med J 2: 7. 1969. Davis DQ, Potchen EJ: Brain scanning and intracranial inflammatory disease. Radiology 95: 345, 1970. O’Mara RE. McAfee JG, Chodos RB: The “douohnut” sign in cerebral radioisotopic images. Radiology 72: 581. 1967. Ballantine HT Jr, White JC: Brain abscess. N. Engl J Med 248: 14, 1953. Carey ME, Chou SN, French LA: Experience with brain abscesses. J Neurosurg 36: 1, 1972. Dodge PR, Swartz MN: Bacterial meningitis. A review of selected aspects. N Engl J Med 272: 954, 1965. Blahd WH: Nuclear Medicine, New York, McGraw-Hill Book Co., inc., 1971. Lithander A, Lithander B: The passage of benzyl penicillin in the cerebrospinal fluid after administration in haemophilus influenzae meningitis. Acta Pathol Microbiol Stand 67: 569, 1966. Lithander A: The passage of parenteral ampicillin into the cerebrospinal fluid in haemophilus influenzae meningitis. Acta Pathol Microbial Stand 64: 329, 1965.
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