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Ventriculitis in infants: Diagnosis by color doppler flow imaging
Ventriculitis in Infants: Diagnosis by Color Doppler Flow Imaging Masaru Tatsuno, MD, Motohiro Hasegawa, MD, and Kazuo Okuyama, MD
A color Doppler flow imaging technique was used to study the dynamics of cerebrospinal fluid (CSF) in infants with meningitis. Eight infants with bacterial meningitis (6) or aseptic meningitis (2) were studied with color Doppler imaging of CSF flow for a total of 18 times. In 2 infants with bacterial meningitis, Doppler sonograms of CSF flow were obtained in the aqueduct during the acute stage. The CSF flow demonstrated a to-and-fro motion which was synchronized with cardiac pulsations and respiration. The detection of CSF flow on color Doppler flow imaging in the aqueduct may indicate the existence of ventriculitis. Color Doppler flow imaging is useful for the evaluation of CSF flow dynamics in infants. Tatsuno M, Hasegawa M, Okuyama K. Ventriculitis in infants: Diagnosis by color Doppler flow imaging. Pediatr Neurol 1993;9:127-30.
Introduction Cerebrospinal fluid (CSF) is mainly produced in the choroid plexus of the lateral ventricles and is absorbed by the arachnoid villi. There are 2 types of CSF motion, slow and fast flow; however, little is k n o w n about the fast-flow dynamics in infants. Recently, color Doppler flow imaging (CDFI) was used to evaluate cerebral blood velocity and vascular structure [1,2] and revealed the CSF fastflow dynamics in the aqueduct, third ventricle, fourth ventricle, and foramen of Monro in an infant with intraventricular hemorrhage [3]. Doppler information obtained on CDFI is expressed as color and brightness and is presented together with echoencephalographic anatomic information; however, it is difficult to demonstrate the CSF flow in normal infants because of Doppler ultrasound reflected from moving blood cells. Bacterial meningitis often results in significant neurologic complications; ventriculitis and post-meningitic hydrocephalus are two of the major complications in infants. It is important, therefore, to ascertain the CSF flow dynamics in meningitis. Although real-time cranial ultrasound findings have been reported to be useful in the
From the Departmentof Pediatrics; Showa UniversitySchool of Medicine; Tokyo, Japan.
detection of complications of meningitis [4-8], including ventriculitis and post-meningitic hydrocephalus, there is no information about CSF fast-flow dynamics. Because infants with meningitis have many inflammatory cells in the aqueduct, the CSF flow velocity may be measured by CDFI. This study illustrates that CDFI demonstrates CSF dynamics in some infants with meningitis.
Methods Eighteen CDFI examinations were performed on 8 infants younger than 1 year of age admitted to the Department of Pediatrics, Showa University School of Medicine, with the diagnosis of meningitis.The clinical features of the 8 patients are summarizedin Table 1. The diagnosis of meningitisbased on the results of CSF examinationand ventricular involvement was confirmed by computed tomography (CT) and/or magnetic resonance imaging (MRI), and ultrasound examinations. CT and MRI were performed with and withoutcontrast enhancement. Ventricularpuncture was not performed because of the hazards involved,except in Patient 2. Sonograms were obtained with a CDFI system (SSA-270A; Toshiba Corp., Tokyo) with a 3.75 MHz medium-focusedelectronicsector transducer. Using the anterior fontanel as an acoustic window, a midsagittal scan was obtained for CSF flow imaging. CDFI clearly demonstrated the ventricle, cisterns, and vascular structures. Flow toward the transducer is depicted in red, whereas flow away from it is depicted in blue. In most patients, we do not need to consider the effect of the angle of insonationin the aqueduct on flow velocitybecause the directionof the ultrasound beam and the CSF flow are parallel. But if needed, we can correct for the angle of incidenceof the ultrasoundbeam. We calculated the average flow velocities while recording for 20 s. The examinations were performed as part of the routine ultrasoundstudy at the bedside of each patient.
Results The results of the CDFI examinations are summarized in Table 2. Patient 1. A 7-month-old girl was admitted with fever, drowsiness, and seizures. L u m b a r puncture revealed 8,530 leukocytes/mm 3. Haemophilus influenzae g r e w from both CSF and blood. CT scans disclosed bilateral subdural effusion and infarction in the right fronto-temporal area. On the day of admission, CSF flow was observed in the aqueduct (Fig 1), third ventricle, and foramen of Monro on CDFI. CDFI revealed that the velocity changed synchronously with the heart beat. The average
Communicationsshould be addressed to: Dr. Tatsuno;Departmentof Pediatrics; Showa UniversitySchool of Medicine; 1-5-8, Hatanodai, Shinagawa-ku;Tokyo 142, Japan. Received October 21, 1992; accepted February 8, 1993.
Tatsunoet al: CSF Flow in Ventriculitis 127
Table 1. Clinical findings in 8 patients with meningitis Patient No./Sex
Age at Diagnosis
Causative Organisms
I/F
7 mos
Haemophilus il!fluenzae
Ventriculitis. subdural effusion. infarction, hydrocephalus Ventriculitis, hydrocephalus
Complications
2/M
10 d a y s
Escherichia coli
3/F
4 days
Escherichia coli
4/M
6 mos
Haemophilus influenzae
5/F
6 mos
Haemophilus it~uenzae
Subduraleffusion
6/F
8 mos
Haemophilus infIuenzae
Subduraleffusion
7/F
1 mo
Aseptic
8/F
5 mos
Aseptic
peak velocities in the aqueduct were upward 6 cm/s and downward 7 cm/s. On days 2 and 4, Doppler examinations demonstrated similar findings. Figure 2 illustrates a recording obtained on spontaneous breathing on day 2, revealing that the velocity changed synchronously with the heart beat and respiration. The average peak velocities were upward 8 crn/s and downward 10 cm/s. On day 10, CSF flow was no longer observed in the aqueduct. CSF c o n t a i n e d 89 leukocytes/mm 3. Follow-up ultrasound scans disclosed moderate ventricular dilatation and ventricular strands and echogenic membranes attached to the
ependymal surface, which indicated ventrtcular inw)lve ment. After 1 month, a ventriculoperitoneal shunt was inserted for communicating hydrocephalus. She eventually developed spastic quadfiplegia and severe mental retardation at 28 months of age. P a t i e n t 2. This 10-day-old boy was admitted with fever, apnea, and lethargy. CSF contained 40.800 leukocytes/mm 3. E s c h e r i c h i a coli grew from both blood and CSE MRI revealed brain edema and subdural effusion. CSF flow was observed in the aqueduct and third ventricle on CDFI. The CSF flow demonstrated a to-and-fro motion synchronous with the heart beat and respiration. This examination was repeated on the next day and the findings were similar. The average peak velocities in the aqueduct were upward 4 cm/s and downward 5 cm/s. On day 7, CSF flow was no longer observed in the aqueduct. Despite intravenous antibiotics, the infant developed seizures and exhibited neurologic deterioration. Follow-up ultrasound scans revealed moderate ventricular dilatation, and ventricular strands and membranes of echogenic material attached to the ventricular surface. Temporary ventriculostomy with external drainage was required because of rapid development of increased intracranial pressure and ventricular dilatation at 1 month. Ventricular fluid examination revealed 186 leukocytes/mm 3 and 430 mg/dl protein. A ventriculoperitoneal shunt was inserted at 3 months for communicating hydrocephalus. He eventually developed spastic quadriplegia and severe mental retardation evident by 24 months of age. In Patients 3-8, who exhibited uncomplicated ventriculitis on ultrasound examination, CT, and MRI, Doppler sonograms of CSF flow could not be obtained during the acute stage. Follow-up ultrasound examinations, CT, and/or MRI demonstrated normal findings in 4 patients, although transient subdural effusion was observed in 2.
Figure 1. CDFI of CSF flow. A midsagittal scan through the anterior Jbntanel. CDFI clearly demonstrates the intracranial structure and vessels. The CSF flow in the aqueduct is depicted in red which means that there is flow toward the transducer. An arrow indicates CSF flow in the aqueduct. CB: cerebellum, 3: third ventricle, 4:.fourth ventricle, SS: straight sinus, ICV: internal cerebral vein.
128 PEDIATRICNEUROLOGY Vol.9 No. 2
Table 2. CDFI findings in 8 patients with meningitis CSF Findings LeukoProtein cytesdmm3 (mg/dl)
Pt. No.
Day of Hospitalization
1
1
To-and-fro motion; 6/7
8,530
150
Subdural effusion
2
To-and-fro motion; 8/10
21,200
123
Subdural effusion
4
To-and-fro motion; 4/5
302
62
Subdural effusion, infarction
10
Not detected
89
41
Subdural effusion, infarction, ventriculitis
1
To-and-fro motion; 4/5
40,800
479
Brain edema, subdural effusion
2
To-and-fro motion; 4/4
--
--
Subdural effusion
7
Not detected
9,600
575
Ventriculomegaly
14
Not detected
90
578
Ventriculitis, hydrocephalus
3
1,2
Not detected
341
135
Normal
4
1,2
Not detected
4,949
135
Normal
5
1,2
Not detected
17,200
81
Normal
6
1,2
Not detected
4,500
143
7
1
Not detected
155
91
Normal
8
1
Not detected
102
28
Normal
2
CSF Flow and Velocities (upward/downward; cnffs)
All of them were normally developed on follow-up. The lengths of follow-up ranged 10-27 months (mean: 19 months). Discussion There are 2 types of CSF motion, slow and fast flow. Slow flow is due to the production of CSF by the choroid
Figure 2. Pulsed Doppler sonogram of CSF flow with a respiration curve. The sample volume was placed in the aqueduct: pulsed Doppler recording reveals a to-and-fro motion. The velocity changed synchronously with the heart beat and respiration.
Ultrasound, CT, and/or MRI
Subdural effusion
plexus. Fast flow was previously demonstrated to be pulsatile on myelography or MRI, a phenomenon due to transmitted cardiac pulsation [9-15] and respiration [10,15]. Recently, we used CDFI to evaluate the CSF flow velocity in an infant with intraventricular hemorrhage; CSF flow was detected in the foramen of Monro, aqueduct, third ventricle, and fourth ventricle [3]. CDFI has the advantage of providing dynamic data at the bedside without the movement of a critically ill infant. In this study, we investigated the CDFI appearance of CSF flow in the aqueduct of patients with meningitis. In 2 patients, the CSF flow velocity in the aqueduct could be determined on CDFI. The pulsatile movement of CSF through the ventricular system appeared on scanning as an area of red and blue color which was best observed in the aqueduct, the narrowest point of the ventricular system. CSF flow comprises a rapid to-and-fro motion due to transmitted cardiac pulsations and respiration, and the flow velocities in our patients ranged 4-10 crn/s. The velocities were higher than that reported in normal adults measured by MRI [11,14]. This difference may be due to the measurement method, age, or complicating diseases. Intracranial pressure, intracranial CSF volume, and intravascular blood volume may also contribute to the CSF motion and velocity. Ventriculitis is a common complication of neonatal meningitis [16-18]. The diagnosis of ventriculitis is deter-
Tatsuno et al: CSF Flow in Ventriculitis
129
mined by ventricular puncture. The presence of bacteria or a bacterial antigen in the ventricular fluid and a leukocyte cell count in excess of approximately 100 leukocytes/mm 3 indicate ventriculitis [19]; however, ventricular puncture is hazardous and may be difficult in small ventricles. Recently, several investigators illustrated that ultrasound findings, including ventriculomegaly, intraventricular echogenic material, echogenic ependymal regions, and ventricular strands and membranes, are correlated to pathologic changes of ventricular involvement, and real-time ultrasound examination is useful as a diagnostic procedure for the presence of ventriculitis [4-8]. In 2 of our patients who manifested CSF flow, intraventricular strands and membranes were observed later in the course of the illness on ultrasound examination, CT, or MRI. These findings indicated ventricular involvement and ventriculitis. It was suggested that CDFI may provide an early diagnosis of ventriculitis. In patients with meningitis, many leukocytes are manifest during the acute stage in the subarachnoid space. When a patient has ventriculitis, it is suggested that there are many inflammatory cells in the aqueduct and the CSF flow velocity may be measured by CDFI. In 2 of our patients, the detection of CSF flow on CDFI is probably due to the presence of moving inflammatory cellular infiltrates, cellular debris, or fibrin strands in the aqueduct; therefore, CDFI can be used to detect erythrocytes or leukocytes in ventricles and to study CSF fast-flow dynamics in meningitis; however, it is difficult to determine the number of leukocytes in the ventricle without ventricular puncture and the sensitivity of CDFI remains to be determined. The ability of the Doppler technique to measure flow velocity is based on the presence of particulate or cellular matter within the fluid studied. The sensitivity of the CDFI technique is influenced by several factors. Such factors are the ability of the Doppler instrument to detect the flow at low velocities, the cell counts in the area of study, and the size of the aqueduct. Despite these limitations, depiction of the CSF flow which indicates moving cellular matter within the studied area, is one of the useful indications of ventriculitis. But it must be correlated with the results of other examinations to be interpreted correctly, especially when CSF flow is not depicted. In contrast, CDFI could not demonstrate the CSF flow without ventriculitis or intracranial hemorrhage because Doppler ultrasound is usually reflected by moving blood cells. CDFI is useful for the noninvasive assessment of CSF flow dynamics in infants with meningitis. The informa-
130
PEDIATRIC NEUROLOGY
Vol. 9 No. 2
tion obtained on CDF1 may facilitate evaluation ol lhe CSF circulation in infants with meningitis. ('DFI ntay have potential clinical applications for the investigation of a variety of CSF flow abnormalities, such as intraventricular hemorrhage and meningitis.
References
[1] Tatsuno M, Kubota T, Okuyama K, Kawauchi A. lntracranial vessels with color Doppler echoencephalography in infants. Brain Dev 1989;11:125-30. [2] Wong WS, Tsuruda JS, Liberman RL. Chirino A, Vogt JF, Gangitano E. Color Doppler imaging of intracranial ves~ls in the neonate. AJNR 1989;10:425-30. [3] Tatsuno M, Uchida K, Okuyama K, Kawauchi A. Color Doppler flow imaging of CSF flow in an infant with intraventricular hemorrhage. Brain Dev 1992;14:110-3. [4] Edwards MK, Brown DL, Chua GT. Complicated infantile meningitis: Evaluation by real-time sonography. AJNR 1982;3:43 I-4. [5] Hill A, Shackelford GD, Volpe JJ. Ventriculitis with neonatal bacterial meningitis: Identification by real-time ultrasound. J Pediatr 198l;99:133-6. [6] Reeder JD, Sanders RC. Ventriculitis in the neonate: Recognition by sonography. AJNR 1983;4:37-41. [7] Rosenberg HK, Levine RS, Stoltz K, Smith DR. Bacterial meningitis in infants: Sonographic features. AJNR 1983;4:822-5. [8] Han BK, Babcock DS, McAdams L. Bacterial meningitis in infants: Sonographic findings. Radiology 1985; 154:645-50. [9] DuBoulay GH. Pulsatile movements in the CSF pathways. Br J Radiol 1966;39:255-62. [10] Lane B, Kricheff II. Cerebrospinal fluid pulsations at myelography: A videodensitometric study. Radiology 1974; 110:579-87. [11] Quencer RM, Post M.ID, Hinks RS. Cine MR in the evaluation of normal and abnormal CSF flow: Intracranial and intraspinal studies. Neuroradiology 1990;32:371-91. [12] Enzmann DR, Pelc NJ. Normal flow patterns of intracranial and spinal cerebrospinal fluid defined with phase-contrast cine MR imaging. Radiology 1991 ;178:467-74. [13] Curless RG, Quencer RM, Katz DA, Campanioni M. Magnetic resonance demonstration of intracranial CSF flow in children. Neurology 1992;42:377-81. [14] Thomsen C, StShlberg F, Stugaard M, Nordell B. Fourier analysis of cerebrospinal fluid flow velocity: MR imaging study. Radiology 1990; 177:659-65. [15] Kahn T, MOiler E, Lewin JS, Mrdder U. MR measurement of spinal CSF flow with the RACE technique. J Comput Assist Tomogr 1992;16:54-61. [16] Berman PH, Banker BQ. Neonatal meningitis: A clinical and pathological study of 29 cases. Pediatrics 1966;38:6-24. [17] GUles FH, James JL, Berenberg W. Neonatal meningitis: The ventricle as a bacterial reservoir. Arch Neurol 1977;34:560-2. [18] McCracken GH, Mize SG, Threlkeld N. Intraventricular gentamicin therapy in gram-negative bacillary meningitis of infancy, Lancet 1980;1:787-91. [19] Volpe JJ. Neurology of the newborn, 2nd ed. Philadelphia: WB Saunders, 1987;612.
A color Doppler flow imaging technique was used to study the dynamics of cerebrospinal fluid (CSF) in infants with meningitis. Eight infants with bacterial meningitis (6) or aseptic meningitis (2) were studied with color Doppler imaging of CSF flow for a total of 18 times. In 2 infants with bacterial meningitis, Doppler sonograms of CSF flow were obtained in the aqueduct during the acute stage. The CSF flow demonstrated a to-and-fro motion which was synchronized with cardiac pulsations and respiration. The detection of CSF flow on color Doppler flow imaging in the aqueduct may indicate the existence of ventriculitis. Color Doppler flow imaging is useful for the evaluation of CSF flow dynamics in infants. Tatsuno M, Hasegawa M, Okuyama K. Ventriculitis in infants: Diagnosis by color Doppler flow imaging. Pediatr Neurol 1993;9:127-30.
Introduction Cerebrospinal fluid (CSF) is mainly produced in the choroid plexus of the lateral ventricles and is absorbed by the arachnoid villi. There are 2 types of CSF motion, slow and fast flow; however, little is k n o w n about the fast-flow dynamics in infants. Recently, color Doppler flow imaging (CDFI) was used to evaluate cerebral blood velocity and vascular structure [1,2] and revealed the CSF fastflow dynamics in the aqueduct, third ventricle, fourth ventricle, and foramen of Monro in an infant with intraventricular hemorrhage [3]. Doppler information obtained on CDFI is expressed as color and brightness and is presented together with echoencephalographic anatomic information; however, it is difficult to demonstrate the CSF flow in normal infants because of Doppler ultrasound reflected from moving blood cells. Bacterial meningitis often results in significant neurologic complications; ventriculitis and post-meningitic hydrocephalus are two of the major complications in infants. It is important, therefore, to ascertain the CSF flow dynamics in meningitis. Although real-time cranial ultrasound findings have been reported to be useful in the
From the Departmentof Pediatrics; Showa UniversitySchool of Medicine; Tokyo, Japan.
detection of complications of meningitis [4-8], including ventriculitis and post-meningitic hydrocephalus, there is no information about CSF fast-flow dynamics. Because infants with meningitis have many inflammatory cells in the aqueduct, the CSF flow velocity may be measured by CDFI. This study illustrates that CDFI demonstrates CSF dynamics in some infants with meningitis.
Methods Eighteen CDFI examinations were performed on 8 infants younger than 1 year of age admitted to the Department of Pediatrics, Showa University School of Medicine, with the diagnosis of meningitis.The clinical features of the 8 patients are summarizedin Table 1. The diagnosis of meningitisbased on the results of CSF examinationand ventricular involvement was confirmed by computed tomography (CT) and/or magnetic resonance imaging (MRI), and ultrasound examinations. CT and MRI were performed with and withoutcontrast enhancement. Ventricularpuncture was not performed because of the hazards involved,except in Patient 2. Sonograms were obtained with a CDFI system (SSA-270A; Toshiba Corp., Tokyo) with a 3.75 MHz medium-focusedelectronicsector transducer. Using the anterior fontanel as an acoustic window, a midsagittal scan was obtained for CSF flow imaging. CDFI clearly demonstrated the ventricle, cisterns, and vascular structures. Flow toward the transducer is depicted in red, whereas flow away from it is depicted in blue. In most patients, we do not need to consider the effect of the angle of insonationin the aqueduct on flow velocitybecause the directionof the ultrasound beam and the CSF flow are parallel. But if needed, we can correct for the angle of incidenceof the ultrasoundbeam. We calculated the average flow velocities while recording for 20 s. The examinations were performed as part of the routine ultrasoundstudy at the bedside of each patient.
Results The results of the CDFI examinations are summarized in Table 2. Patient 1. A 7-month-old girl was admitted with fever, drowsiness, and seizures. L u m b a r puncture revealed 8,530 leukocytes/mm 3. Haemophilus influenzae g r e w from both CSF and blood. CT scans disclosed bilateral subdural effusion and infarction in the right fronto-temporal area. On the day of admission, CSF flow was observed in the aqueduct (Fig 1), third ventricle, and foramen of Monro on CDFI. CDFI revealed that the velocity changed synchronously with the heart beat. The average
Communicationsshould be addressed to: Dr. Tatsuno;Departmentof Pediatrics; Showa UniversitySchool of Medicine; 1-5-8, Hatanodai, Shinagawa-ku;Tokyo 142, Japan. Received October 21, 1992; accepted February 8, 1993.
Tatsunoet al: CSF Flow in Ventriculitis 127
Table 1. Clinical findings in 8 patients with meningitis Patient No./Sex
Age at Diagnosis
Causative Organisms
I/F
7 mos
Haemophilus il!fluenzae
Ventriculitis. subdural effusion. infarction, hydrocephalus Ventriculitis, hydrocephalus
Complications
2/M
10 d a y s
Escherichia coli
3/F
4 days
Escherichia coli
4/M
6 mos
Haemophilus influenzae
5/F
6 mos
Haemophilus it~uenzae
Subduraleffusion
6/F
8 mos
Haemophilus infIuenzae
Subduraleffusion
7/F
1 mo
Aseptic
8/F
5 mos
Aseptic
peak velocities in the aqueduct were upward 6 cm/s and downward 7 cm/s. On days 2 and 4, Doppler examinations demonstrated similar findings. Figure 2 illustrates a recording obtained on spontaneous breathing on day 2, revealing that the velocity changed synchronously with the heart beat and respiration. The average peak velocities were upward 8 crn/s and downward 10 cm/s. On day 10, CSF flow was no longer observed in the aqueduct. CSF c o n t a i n e d 89 leukocytes/mm 3. Follow-up ultrasound scans disclosed moderate ventricular dilatation and ventricular strands and echogenic membranes attached to the
ependymal surface, which indicated ventrtcular inw)lve ment. After 1 month, a ventriculoperitoneal shunt was inserted for communicating hydrocephalus. She eventually developed spastic quadfiplegia and severe mental retardation at 28 months of age. P a t i e n t 2. This 10-day-old boy was admitted with fever, apnea, and lethargy. CSF contained 40.800 leukocytes/mm 3. E s c h e r i c h i a coli grew from both blood and CSE MRI revealed brain edema and subdural effusion. CSF flow was observed in the aqueduct and third ventricle on CDFI. The CSF flow demonstrated a to-and-fro motion synchronous with the heart beat and respiration. This examination was repeated on the next day and the findings were similar. The average peak velocities in the aqueduct were upward 4 cm/s and downward 5 cm/s. On day 7, CSF flow was no longer observed in the aqueduct. Despite intravenous antibiotics, the infant developed seizures and exhibited neurologic deterioration. Follow-up ultrasound scans revealed moderate ventricular dilatation, and ventricular strands and membranes of echogenic material attached to the ventricular surface. Temporary ventriculostomy with external drainage was required because of rapid development of increased intracranial pressure and ventricular dilatation at 1 month. Ventricular fluid examination revealed 186 leukocytes/mm 3 and 430 mg/dl protein. A ventriculoperitoneal shunt was inserted at 3 months for communicating hydrocephalus. He eventually developed spastic quadriplegia and severe mental retardation evident by 24 months of age. In Patients 3-8, who exhibited uncomplicated ventriculitis on ultrasound examination, CT, and MRI, Doppler sonograms of CSF flow could not be obtained during the acute stage. Follow-up ultrasound examinations, CT, and/or MRI demonstrated normal findings in 4 patients, although transient subdural effusion was observed in 2.
Figure 1. CDFI of CSF flow. A midsagittal scan through the anterior Jbntanel. CDFI clearly demonstrates the intracranial structure and vessels. The CSF flow in the aqueduct is depicted in red which means that there is flow toward the transducer. An arrow indicates CSF flow in the aqueduct. CB: cerebellum, 3: third ventricle, 4:.fourth ventricle, SS: straight sinus, ICV: internal cerebral vein.
128 PEDIATRICNEUROLOGY Vol.9 No. 2
Table 2. CDFI findings in 8 patients with meningitis CSF Findings LeukoProtein cytesdmm3 (mg/dl)
Pt. No.
Day of Hospitalization
1
1
To-and-fro motion; 6/7
8,530
150
Subdural effusion
2
To-and-fro motion; 8/10
21,200
123
Subdural effusion
4
To-and-fro motion; 4/5
302
62
Subdural effusion, infarction
10
Not detected
89
41
Subdural effusion, infarction, ventriculitis
1
To-and-fro motion; 4/5
40,800
479
Brain edema, subdural effusion
2
To-and-fro motion; 4/4
--
--
Subdural effusion
7
Not detected
9,600
575
Ventriculomegaly
14
Not detected
90
578
Ventriculitis, hydrocephalus
3
1,2
Not detected
341
135
Normal
4
1,2
Not detected
4,949
135
Normal
5
1,2
Not detected
17,200
81
Normal
6
1,2
Not detected
4,500
143
7
1
Not detected
155
91
Normal
8
1
Not detected
102
28
Normal
2
CSF Flow and Velocities (upward/downward; cnffs)
All of them were normally developed on follow-up. The lengths of follow-up ranged 10-27 months (mean: 19 months). Discussion There are 2 types of CSF motion, slow and fast flow. Slow flow is due to the production of CSF by the choroid
Figure 2. Pulsed Doppler sonogram of CSF flow with a respiration curve. The sample volume was placed in the aqueduct: pulsed Doppler recording reveals a to-and-fro motion. The velocity changed synchronously with the heart beat and respiration.
Ultrasound, CT, and/or MRI
Subdural effusion
plexus. Fast flow was previously demonstrated to be pulsatile on myelography or MRI, a phenomenon due to transmitted cardiac pulsation [9-15] and respiration [10,15]. Recently, we used CDFI to evaluate the CSF flow velocity in an infant with intraventricular hemorrhage; CSF flow was detected in the foramen of Monro, aqueduct, third ventricle, and fourth ventricle [3]. CDFI has the advantage of providing dynamic data at the bedside without the movement of a critically ill infant. In this study, we investigated the CDFI appearance of CSF flow in the aqueduct of patients with meningitis. In 2 patients, the CSF flow velocity in the aqueduct could be determined on CDFI. The pulsatile movement of CSF through the ventricular system appeared on scanning as an area of red and blue color which was best observed in the aqueduct, the narrowest point of the ventricular system. CSF flow comprises a rapid to-and-fro motion due to transmitted cardiac pulsations and respiration, and the flow velocities in our patients ranged 4-10 crn/s. The velocities were higher than that reported in normal adults measured by MRI [11,14]. This difference may be due to the measurement method, age, or complicating diseases. Intracranial pressure, intracranial CSF volume, and intravascular blood volume may also contribute to the CSF motion and velocity. Ventriculitis is a common complication of neonatal meningitis [16-18]. The diagnosis of ventriculitis is deter-
Tatsuno et al: CSF Flow in Ventriculitis
129
mined by ventricular puncture. The presence of bacteria or a bacterial antigen in the ventricular fluid and a leukocyte cell count in excess of approximately 100 leukocytes/mm 3 indicate ventriculitis [19]; however, ventricular puncture is hazardous and may be difficult in small ventricles. Recently, several investigators illustrated that ultrasound findings, including ventriculomegaly, intraventricular echogenic material, echogenic ependymal regions, and ventricular strands and membranes, are correlated to pathologic changes of ventricular involvement, and real-time ultrasound examination is useful as a diagnostic procedure for the presence of ventriculitis [4-8]. In 2 of our patients who manifested CSF flow, intraventricular strands and membranes were observed later in the course of the illness on ultrasound examination, CT, or MRI. These findings indicated ventricular involvement and ventriculitis. It was suggested that CDFI may provide an early diagnosis of ventriculitis. In patients with meningitis, many leukocytes are manifest during the acute stage in the subarachnoid space. When a patient has ventriculitis, it is suggested that there are many inflammatory cells in the aqueduct and the CSF flow velocity may be measured by CDFI. In 2 of our patients, the detection of CSF flow on CDFI is probably due to the presence of moving inflammatory cellular infiltrates, cellular debris, or fibrin strands in the aqueduct; therefore, CDFI can be used to detect erythrocytes or leukocytes in ventricles and to study CSF fast-flow dynamics in meningitis; however, it is difficult to determine the number of leukocytes in the ventricle without ventricular puncture and the sensitivity of CDFI remains to be determined. The ability of the Doppler technique to measure flow velocity is based on the presence of particulate or cellular matter within the fluid studied. The sensitivity of the CDFI technique is influenced by several factors. Such factors are the ability of the Doppler instrument to detect the flow at low velocities, the cell counts in the area of study, and the size of the aqueduct. Despite these limitations, depiction of the CSF flow which indicates moving cellular matter within the studied area, is one of the useful indications of ventriculitis. But it must be correlated with the results of other examinations to be interpreted correctly, especially when CSF flow is not depicted. In contrast, CDFI could not demonstrate the CSF flow without ventriculitis or intracranial hemorrhage because Doppler ultrasound is usually reflected by moving blood cells. CDFI is useful for the noninvasive assessment of CSF flow dynamics in infants with meningitis. The informa-
130
PEDIATRIC NEUROLOGY
Vol. 9 No. 2
tion obtained on CDF1 may facilitate evaluation ol lhe CSF circulation in infants with meningitis. ('DFI ntay have potential clinical applications for the investigation of a variety of CSF flow abnormalities, such as intraventricular hemorrhage and meningitis.
References
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