- Email: [email protected]
BLOCKED EAR AFTER EXTRADURAL INJECTION
666
BRITISH JOURNAL OF ANAESTHESIA
(1986). Absence of interaction of cimetidine and ranitidinc with intravenous and oral midazolam. Anesth. Analg., 65, 176. Kiotz, U., Arvela, P., and Rosenkranz, B. (1985). Effect of single doses of cimetidine and ranitidine on the steady state plasma levels of midazolam. Clin. Pharmacol. Ther., 38, 652. Wilson, C. M., Robinson, F. P., Thompson, E. M., Dundee, J. W., and Elliott, P. (1986). Effect of pretreatment with ranitidine on the hypnotic action of single doses of midazolam, temazepam and zopiclone. Br. J. Anaesth., 58, 483.
Downloaded from http://bja.oxfordjournals.org/ at East Carolina University on June 30, 2015
Hardy noted that these symptoms of slight endolymphatic hydrops can occur after decreased CSF and perilymph pressures, but still claimed his patients' problems were caused by increased pressures. However, his findings are quite consistent with the more generally applicable low pressure theory. Note that: (1) Symptoms occurred immediately after, rather than during, injection at a time CSF pressure is rapidly decreasing (Usubiaga, Wikinski and Usubiaga, 1967). (2) Injection causes arterial pressure to decrease (Lund, 1971). Hydrops is associated with arterial hypo-, not hyper-, tension (Gordon, 1983). (3) There may have been undetected dural puncture, with Sir,—I admit the omission of the word "randomized" from CSF leak or decompression. the methodology and apologize for this error. However, I (4) Two patients were young women. Injection CSF pressures would have hoped that we were a sufficiently reputable group are higher in older patients (Usubiaga, Wikinski and Usubiaga, 1967), while low pressure headaches are commoner in younger of workers that it would be realized that this was a mistake. Increasing the numbers in two series does not introduce bias patients (Lund, 1971). CSF hydrodynamics are complex and it is easy to make false provided, as we have stated, "neither patients nor observers knew the medication given". I was not involved in the assumptions. Thus it is generally considered that aqueduct observations or the anaesthesia, but I kept a constant watch on stenosis is caused by hydrocephalus, even though the narrow the findings and without the knowledge of my junior lumen strongly suggests a centripetal pressure gradient with colleagues, withdrew temazepam and zopiclone after 120 low pressures in parts of the CSF system (Gordon, 1984). observations, restricting the study thereafter to midazolam. There has long been confusion as to whether postspinal With two operating lists per week containing one or two puncture headache is the result of increased or decreased CSF suitable patients, this had already taken about 1 year. Since pressure (Lund, 1971). Aboulker (1919) claimed Meniere's most lecturers and research fellows have a 1-year contract, any syndrome was the result of intracranial and labyrinthine hypertension and that symptoms (but not deafness) were alternative would have introduced a new group of observers. The very exhaustive survey of our method of evaluation by relieved by decompression. However, instead of the expected Morrison, Hill and Dundee (1968) showed the fears of observer jet of CSF at lumbar puncture, it often came out drop by drop difference to be negligible. The alternative of one person or even a dribble. His explanation was that pressures vary at making 120 or 144 observations is quite unacceptable because different parts of the CSF system. of the problem of boredom and inadvertent attempts at There are more general reasons for discounting a causal "breaking the code". increase in pressure. Hydrops symptoms do not occur in Your correspondent can have little contact with the real intracranial hypertension from space-occupying lesions, world of clinical research to consider lack of "money, although vertigo may be a late brainstem symptom (Zulch, availability of staff and time" as excuses for an incomplete Mennel and Zimmermann, 1974). There is no aural analog of study—they are facts of life. It he wants another, our hospital papilloedema or congestive inner ear (Kaaber and Zilstorff, 1978). Nor do they occur in pseudotumor cerebri, although a unit was due for closure. With decreasing resources, one might well take a realistic case of hydrops-type deafness has been reported (Sismanis look at some of the "sacred cows" in clinical research. This et al., 1985). Significantly, they did not attribute this to inletter is a good example of them. The first 120 observations creased perilymph pressure, despite immediate remission of occupied about 1000 man-hours. It was not only good science, deafness and tinnitus upon drainage of CSF, since the deafbut good stewardship of resources (which include manpower) ness also remitted during jugular vein compression, which increases CSF and perilymph pressures. to complete the study as reported. It is important to determine if high CSF pressure ever causes J. W. DUNDEE early hydrops symptoms, since otherwise they will be specific Belfast to CSF hypotension, unlike all the other symptoms which are common to CSF hyper- and hypotension (Frederiks, 1976). They would then be a simple and very useful clinical indicator REFERENCE of low pressure in lumbar puncture headache, overshunted Morrison, J. D., Hill, G. B., and Dundee, J. W. (1968). hydrocephalus, spaceflight sickness, psychiatric disease, etc. Studies of drugs given before anaesthesia. XV: Evaluation Furthermore, the misleading high pressure theories of the of the method of study after 10000 observations. Br. J. causation of Meniere's disease could be discarded. The way to Anaesth., 40, 890. settle the issue is to question patients carefully during CSF pressure measurements for all the symptoms of hydrops. The full early hydrops syndrome comprises a blocked ear, fluctuant low tone deafness or, on occasion, improved pure tone BLOCKED EAR AFTER EXTRADURAL INJECTION sensitivity, vertigo, tinnitus, audiosensitivity and lowered Sir,—Hardy (1986) reported three patients with hypoacusis acoustic reflex thresholds (Gordon, 1986). The effect of after extradural injection. In fact they complained of a blocked posture should be noted, since low pressure symptoms should ear (sensation of fullness or cotton wool). While hypoacusis is improve on lying down, while high pressure ones worsen. usually associated with subjective hearing difficulty and low Finally, idiosyncratic differences, in temporal bone anatomy tone hearing loss, these may be absent. Serial pure tone or otological history perhaps, must predominate over general audiometry is needed to establish the hypoacusis. theoretical considerations, since side-effects occur in only a
CORRESPONDENCE
667
(5) The patients were horizontal throughout which, as Dr Gordon notes, would minimize or negate any low pressure effect. A. G. GORDON It would be interesting to know exactly on what experimental London data Dr Gordon bases his low pressure theory. In the sources he quotes there is one clear description of "hydrops syndrome" associated with increased intracranial pressure REFERENCES which responded to CSF drainage (Sismanis et al., 1985). Since my original letter I have noted both auditory and, in Aboulker, H. (1919). Traitement de certaines formes du vertige de Meniere par la trepanation decompressive. Rev. particular, vestibular disturbance in a patient during extradural injection of steroid—saline mixture in the treatment of low back Newol., 35, 493. Fredcriks, J. A. M. (1974). Post-traumatic CSF hypotension. pain. The 37-yr-old woman had a history of Menicrcs disease, but was in remission. An extradural puncture was performed Handbook Clin. Neurol., 24, 255. Gordon, A. G. (1983). Meniere's disease: endolymphatic at L2-3 with the patient in a left lateral position. Injection of hypertension or perilymphatic hypotension? Clin. Otlaryn- a solution of methylprednisolone 40 mg in 10.9% sodium chloride was performed at a rate of 4 ml min" . By the time gol., 8, 293. (1984). Endolymphatic hydrops and CSF pressure. J. 16 ml had been injected, the procedure had to be abandoned because of disabling waves of vertigo and the feeling of nausea. Neurosurg., 60, 1332. (1986). Abnormal middle ear muscle reflexes and These symptoms persisted for about 5 min before gradually subsiding. Arterial pressure was stable throughout. The audiosensitivity. Br. J. Audiology, 20, 95. Hardy, P. A. J. (1986). Hypoacusis following extradural patient would not open her eyes during injection, so that it was not possible to check for nystagmus. After an uneventful injection. Br.J. Anaesth., 58, 573. Kaaber, E. G., and Zilstorff, K. (1978). Vestibular function in recovery she described marked tinnitus and almost complete benign intracranial hypertension. Clin. Otolaryngol., 3, 183. deafness during this episode. She also remarked that the Lund, P. C. (1971). Principles and Practice of Spinal Anesthesia.symptoms were identical with but more severe than those she experienced with the Menieres. In this patient, vestibular Springfield: Thomas. Sismanis, A., Hughes, G. B., Abedi, E., Williams, G. H., and disturbance predominated although auditory disturbance was Isrow, L. A. (1985). Otologic symptoms and findings of the present also. The only change in association with these pseudotumor cerebri syndrome: a preliminary report. symptoms was a slow extradural injection, a procedure which is associated with increased spinal and intracranial pressures. Otolaryngol. Head Neck Surg., 93, 398. Usubiaga, J. E., Wikinski, J. A., and Usubiaga, L. E. (1967). Do these symptoms matter ? There are two reasons why these Epidural puncture and its relation to spread of anesthetic observations are important. To the anaesthetist these same symptoms may be caused by systemic local anaesthetic toxicity solutions in the epidural space. Aneslh. Analg., 46, 440. Zulch, K. J., Mennel, H. D., and Zimmermann, V. (1974). and not, as in this patient, a purely mechanical effect. To the Intracranial hypertension. Handbook Clin. Neurol., 16, 89. otologist the mechanism is important, since there have been no studies of intracranial pressure in patients with VIII nerve diseases. The relationship between ICP and vestibular cochlear mechanisms would be worthy of further study.
few patients, although hydrops symptoms are very easy to miss or misinterpret.
P. A. J. HARDY
Liverpool
REFERENCES Colman, B. H. (1983). Meniere's disease. Clin. Otolaryngol., 8,294. Gordon, A. G. (1983). Meniere's disease. Clin. Otolaryngol., 8, 293. Hardy, P. A. J. (1986). Loss of consciousness after caudal injection. Anaesthesia, 41, 212. Hill, H., Gramm, H.-J., and Link, J. (1986). Changes in intracranial pressure associated with extradural anaesthesia. Br. J. Anaesth., 58, 676. Messih, M. N. A. (1981). Epidural space pressures during pregnancy. Anaesthesia, 36, 775. Sismanis, A., Hughes, G. B., Abedi, E., Williams, G. H., and Isnow, L. A. (1985). Otologic symptoms and findings of the pseudo tumour cerebri syndrome: a preliminary report. Otolaryngol. Head Neck Surg., 93, 398. Usubiaga, J. E., Wilkinski, J. A., and Usubiaga, L. E., (1967). Epidural pressure and its relationship to spread of anesthetic solutions in the epidural space. Anesth. Analg., 36, 44.
Downloaded from http://bja.oxfordjournals.org/ at East Carolina University on June 30, 2015
Sir,—Dr Gordon claims that the evidence I presented is consistent with his claimed description of an exclusive low pressure theory of "Hydrops syndrome" (Gordon, 1983)—a theory based on anecdotal evidence only and refuted in the same journal (Colman, 1983). If I take each of Gordon's points in turn, it is clear that there is no evidence to support a low pressure origin: (1) The CSF pressure decrease described by Usubiaga, Wikinski and Usubiaga (1967) is that from a high pressure towards normal. These workers did not demonstrate any subnormal pressures and, in fact, noted increased residual pressures after injection. It has recently been shown that a similar increase in intracranial pressure occurs during extradural injection (Hilt, Gramm and Link, 1986) which may be prolonged in cases of reduced cerebrospinal compliance (Hardy, 1986). (2) Spinal and extradural analgesia may be associated with a decrease in arterial pressure—well after the time period described. In the cases I described, arterial pressure monitoring showed no change after injection. (3) Dural puncture in the presence of extradural injection of local anaesthetic would result in massive (total) spinal anaesthesia. This did not occur in the patients reported. (4) The young patients described were pregnant women at term in labour. This is associated with increased intraspinal pressures (Messih, 1981).
BRITISH JOURNAL OF ANAESTHESIA
(1986). Absence of interaction of cimetidine and ranitidinc with intravenous and oral midazolam. Anesth. Analg., 65, 176. Kiotz, U., Arvela, P., and Rosenkranz, B. (1985). Effect of single doses of cimetidine and ranitidine on the steady state plasma levels of midazolam. Clin. Pharmacol. Ther., 38, 652. Wilson, C. M., Robinson, F. P., Thompson, E. M., Dundee, J. W., and Elliott, P. (1986). Effect of pretreatment with ranitidine on the hypnotic action of single doses of midazolam, temazepam and zopiclone. Br. J. Anaesth., 58, 483.
Downloaded from http://bja.oxfordjournals.org/ at East Carolina University on June 30, 2015
Hardy noted that these symptoms of slight endolymphatic hydrops can occur after decreased CSF and perilymph pressures, but still claimed his patients' problems were caused by increased pressures. However, his findings are quite consistent with the more generally applicable low pressure theory. Note that: (1) Symptoms occurred immediately after, rather than during, injection at a time CSF pressure is rapidly decreasing (Usubiaga, Wikinski and Usubiaga, 1967). (2) Injection causes arterial pressure to decrease (Lund, 1971). Hydrops is associated with arterial hypo-, not hyper-, tension (Gordon, 1983). (3) There may have been undetected dural puncture, with Sir,—I admit the omission of the word "randomized" from CSF leak or decompression. the methodology and apologize for this error. However, I (4) Two patients were young women. Injection CSF pressures would have hoped that we were a sufficiently reputable group are higher in older patients (Usubiaga, Wikinski and Usubiaga, 1967), while low pressure headaches are commoner in younger of workers that it would be realized that this was a mistake. Increasing the numbers in two series does not introduce bias patients (Lund, 1971). CSF hydrodynamics are complex and it is easy to make false provided, as we have stated, "neither patients nor observers knew the medication given". I was not involved in the assumptions. Thus it is generally considered that aqueduct observations or the anaesthesia, but I kept a constant watch on stenosis is caused by hydrocephalus, even though the narrow the findings and without the knowledge of my junior lumen strongly suggests a centripetal pressure gradient with colleagues, withdrew temazepam and zopiclone after 120 low pressures in parts of the CSF system (Gordon, 1984). observations, restricting the study thereafter to midazolam. There has long been confusion as to whether postspinal With two operating lists per week containing one or two puncture headache is the result of increased or decreased CSF suitable patients, this had already taken about 1 year. Since pressure (Lund, 1971). Aboulker (1919) claimed Meniere's most lecturers and research fellows have a 1-year contract, any syndrome was the result of intracranial and labyrinthine hypertension and that symptoms (but not deafness) were alternative would have introduced a new group of observers. The very exhaustive survey of our method of evaluation by relieved by decompression. However, instead of the expected Morrison, Hill and Dundee (1968) showed the fears of observer jet of CSF at lumbar puncture, it often came out drop by drop difference to be negligible. The alternative of one person or even a dribble. His explanation was that pressures vary at making 120 or 144 observations is quite unacceptable because different parts of the CSF system. of the problem of boredom and inadvertent attempts at There are more general reasons for discounting a causal "breaking the code". increase in pressure. Hydrops symptoms do not occur in Your correspondent can have little contact with the real intracranial hypertension from space-occupying lesions, world of clinical research to consider lack of "money, although vertigo may be a late brainstem symptom (Zulch, availability of staff and time" as excuses for an incomplete Mennel and Zimmermann, 1974). There is no aural analog of study—they are facts of life. It he wants another, our hospital papilloedema or congestive inner ear (Kaaber and Zilstorff, 1978). Nor do they occur in pseudotumor cerebri, although a unit was due for closure. With decreasing resources, one might well take a realistic case of hydrops-type deafness has been reported (Sismanis look at some of the "sacred cows" in clinical research. This et al., 1985). Significantly, they did not attribute this to inletter is a good example of them. The first 120 observations creased perilymph pressure, despite immediate remission of occupied about 1000 man-hours. It was not only good science, deafness and tinnitus upon drainage of CSF, since the deafbut good stewardship of resources (which include manpower) ness also remitted during jugular vein compression, which increases CSF and perilymph pressures. to complete the study as reported. It is important to determine if high CSF pressure ever causes J. W. DUNDEE early hydrops symptoms, since otherwise they will be specific Belfast to CSF hypotension, unlike all the other symptoms which are common to CSF hyper- and hypotension (Frederiks, 1976). They would then be a simple and very useful clinical indicator REFERENCE of low pressure in lumbar puncture headache, overshunted Morrison, J. D., Hill, G. B., and Dundee, J. W. (1968). hydrocephalus, spaceflight sickness, psychiatric disease, etc. Studies of drugs given before anaesthesia. XV: Evaluation Furthermore, the misleading high pressure theories of the of the method of study after 10000 observations. Br. J. causation of Meniere's disease could be discarded. The way to Anaesth., 40, 890. settle the issue is to question patients carefully during CSF pressure measurements for all the symptoms of hydrops. The full early hydrops syndrome comprises a blocked ear, fluctuant low tone deafness or, on occasion, improved pure tone BLOCKED EAR AFTER EXTRADURAL INJECTION sensitivity, vertigo, tinnitus, audiosensitivity and lowered Sir,—Hardy (1986) reported three patients with hypoacusis acoustic reflex thresholds (Gordon, 1986). The effect of after extradural injection. In fact they complained of a blocked posture should be noted, since low pressure symptoms should ear (sensation of fullness or cotton wool). While hypoacusis is improve on lying down, while high pressure ones worsen. usually associated with subjective hearing difficulty and low Finally, idiosyncratic differences, in temporal bone anatomy tone hearing loss, these may be absent. Serial pure tone or otological history perhaps, must predominate over general audiometry is needed to establish the hypoacusis. theoretical considerations, since side-effects occur in only a
CORRESPONDENCE
667
(5) The patients were horizontal throughout which, as Dr Gordon notes, would minimize or negate any low pressure effect. A. G. GORDON It would be interesting to know exactly on what experimental London data Dr Gordon bases his low pressure theory. In the sources he quotes there is one clear description of "hydrops syndrome" associated with increased intracranial pressure REFERENCES which responded to CSF drainage (Sismanis et al., 1985). Since my original letter I have noted both auditory and, in Aboulker, H. (1919). Traitement de certaines formes du vertige de Meniere par la trepanation decompressive. Rev. particular, vestibular disturbance in a patient during extradural injection of steroid—saline mixture in the treatment of low back Newol., 35, 493. Fredcriks, J. A. M. (1974). Post-traumatic CSF hypotension. pain. The 37-yr-old woman had a history of Menicrcs disease, but was in remission. An extradural puncture was performed Handbook Clin. Neurol., 24, 255. Gordon, A. G. (1983). Meniere's disease: endolymphatic at L2-3 with the patient in a left lateral position. Injection of hypertension or perilymphatic hypotension? Clin. Otlaryn- a solution of methylprednisolone 40 mg in 10.9% sodium chloride was performed at a rate of 4 ml min" . By the time gol., 8, 293. (1984). Endolymphatic hydrops and CSF pressure. J. 16 ml had been injected, the procedure had to be abandoned because of disabling waves of vertigo and the feeling of nausea. Neurosurg., 60, 1332. (1986). Abnormal middle ear muscle reflexes and These symptoms persisted for about 5 min before gradually subsiding. Arterial pressure was stable throughout. The audiosensitivity. Br. J. Audiology, 20, 95. Hardy, P. A. J. (1986). Hypoacusis following extradural patient would not open her eyes during injection, so that it was not possible to check for nystagmus. After an uneventful injection. Br.J. Anaesth., 58, 573. Kaaber, E. G., and Zilstorff, K. (1978). Vestibular function in recovery she described marked tinnitus and almost complete benign intracranial hypertension. Clin. Otolaryngol., 3, 183. deafness during this episode. She also remarked that the Lund, P. C. (1971). Principles and Practice of Spinal Anesthesia.symptoms were identical with but more severe than those she experienced with the Menieres. In this patient, vestibular Springfield: Thomas. Sismanis, A., Hughes, G. B., Abedi, E., Williams, G. H., and disturbance predominated although auditory disturbance was Isrow, L. A. (1985). Otologic symptoms and findings of the present also. The only change in association with these pseudotumor cerebri syndrome: a preliminary report. symptoms was a slow extradural injection, a procedure which is associated with increased spinal and intracranial pressures. Otolaryngol. Head Neck Surg., 93, 398. Usubiaga, J. E., Wikinski, J. A., and Usubiaga, L. E. (1967). Do these symptoms matter ? There are two reasons why these Epidural puncture and its relation to spread of anesthetic observations are important. To the anaesthetist these same symptoms may be caused by systemic local anaesthetic toxicity solutions in the epidural space. Aneslh. Analg., 46, 440. Zulch, K. J., Mennel, H. D., and Zimmermann, V. (1974). and not, as in this patient, a purely mechanical effect. To the Intracranial hypertension. Handbook Clin. Neurol., 16, 89. otologist the mechanism is important, since there have been no studies of intracranial pressure in patients with VIII nerve diseases. The relationship between ICP and vestibular cochlear mechanisms would be worthy of further study.
few patients, although hydrops symptoms are very easy to miss or misinterpret.
P. A. J. HARDY
Liverpool
REFERENCES Colman, B. H. (1983). Meniere's disease. Clin. Otolaryngol., 8,294. Gordon, A. G. (1983). Meniere's disease. Clin. Otolaryngol., 8, 293. Hardy, P. A. J. (1986). Loss of consciousness after caudal injection. Anaesthesia, 41, 212. Hill, H., Gramm, H.-J., and Link, J. (1986). Changes in intracranial pressure associated with extradural anaesthesia. Br. J. Anaesth., 58, 676. Messih, M. N. A. (1981). Epidural space pressures during pregnancy. Anaesthesia, 36, 775. Sismanis, A., Hughes, G. B., Abedi, E., Williams, G. H., and Isnow, L. A. (1985). Otologic symptoms and findings of the pseudo tumour cerebri syndrome: a preliminary report. Otolaryngol. Head Neck Surg., 93, 398. Usubiaga, J. E., Wilkinski, J. A., and Usubiaga, L. E., (1967). Epidural pressure and its relationship to spread of anesthetic solutions in the epidural space. Anesth. Analg., 36, 44.
Downloaded from http://bja.oxfordjournals.org/ at East Carolina University on June 30, 2015
Sir,—Dr Gordon claims that the evidence I presented is consistent with his claimed description of an exclusive low pressure theory of "Hydrops syndrome" (Gordon, 1983)—a theory based on anecdotal evidence only and refuted in the same journal (Colman, 1983). If I take each of Gordon's points in turn, it is clear that there is no evidence to support a low pressure origin: (1) The CSF pressure decrease described by Usubiaga, Wikinski and Usubiaga (1967) is that from a high pressure towards normal. These workers did not demonstrate any subnormal pressures and, in fact, noted increased residual pressures after injection. It has recently been shown that a similar increase in intracranial pressure occurs during extradural injection (Hilt, Gramm and Link, 1986) which may be prolonged in cases of reduced cerebrospinal compliance (Hardy, 1986). (2) Spinal and extradural analgesia may be associated with a decrease in arterial pressure—well after the time period described. In the cases I described, arterial pressure monitoring showed no change after injection. (3) Dural puncture in the presence of extradural injection of local anaesthetic would result in massive (total) spinal anaesthesia. This did not occur in the patients reported. (4) The young patients described were pregnant women at term in labour. This is associated with increased intraspinal pressures (Messih, 1981).