Skew Deviation in Pseudotumor Cerebri James
R. Merikangas, M D
Pseudotumor cerebri, or benign intracranial hypertension, when severe, may be associated with extraocular muscle palsies that result in diplopia. Skew deviation refers to a hypertropia that is not the result of a peripheral neuromuscular lesion or of a local mechanical factor in the orbit [ 11. Clinically, skew deviation is characterized by deviation of one eye above the other, which may be hxed or variable with different directions of gaze. Appropriate muscle testing will distinguish it from palsies of the individual vertically acting extraocular muscles. The following is the first description of skew deviation in pseudotumor cerebri. complained of headA 35-year-old fi,&-handeL{ aches and of episodic occurrence of vertical diplopia consisting of the image in the left eye appearing higher than that in the right. She had learned to compensate for this transient disorder by closing one eye. H e r height was 160 cm and weight, 80 kg. Blood pressure was 1801100 and pulse was 96. H e r only medication was oral conrmceptives. There was no neurological abnormality except upon examination of the eyes. T h e pupils were round, regular, and reactive to light and accommodation with an enlarged blind spot in the visual field of the left eye. Vision was otherwise unimpaired. Papilledema was present bilaterally without gross hemorrhages. The extraocular movements were intact without nystagmus. With further observation, however, while the patient was gazing straight ahead, the right eye deviated vertically upward and maintained that position for a few minutes. Both eyes then reverted spontaneously to scraight-ahead gaze without diplopia until ten minutes later, when the right hypertropia returned and lasted for five minutes. N o headache, visual obscurations, or neurological signs accompanied this episode. She underwent four-vessel cranial aneriography by the femoral route and a C T scan of the brain. These studies revealed no abnormaliry other than a small ventricular system. Lumbar puncture revealed clear, colorless cerebrospinal fluid under a pressure of 550 rnm HaO. There were no microscopic or chemical abnormalities. She was treated with Diamox, Decadron, and glycerol and weekly lumbar punctures until the pressure was normal. After a two-year follow-up period free of medication, there has been no recurrence of skew deviation or any other neurological sign.
Discussion Skew deviation occurred in 8% of neuroophthalmological consultations in the series reported by Keane [31. T h e pathophysiology of skew deviation has not been conchsively determined; however, abnormalities of the brainstem, cerebellum, and structures in the posterior fossa have From the University of Pittsburgh. Western Psychiatric Institute and Clinic, 3811 OH- St. Pittsburgh. PA 15261.
Accepted for publicotion June 20. 1978.
been implicated [I, 31. In 1 0 0 cases analyzed by Keane, two-thirds were associated with brainstem strokes. Pontine damage was most frequent, but midbrain-pretectal and medullary lesions were frequent [3]. It is important to distinguish skew deviation from extraocular muscle palsy secondary to peripheral nerve lesions because of the importance of properly localizing the pathological process. Differentiation from a fourth nerve lesion may be difficult [ 2 ] . Because of these ominous implications, the findings in this patient indicate that pseudotumor cerebri should be included in the differential diaffnosis when skew deviation is discovered. &f~eencg~
1. Cogan DG:Neurology of the Ocular Mudrs. Springfield,IL, Thomas, 1975 2. Gordon D. Sever PS: On the fourth crnnial nerve. lancer
2:466, 1976 3. Keane JR:Ocular skew deviation. Arch Neurol 32:185-l9l),
1975
Serum Phenvtoin after EthosAmide Gary W.h w s o n , PhD, ~ and ~~~~~l~ G.Clark, BS
~
~w. lBrown, , j MD,
Information is available [2] regarding drug-drug interactions for most of the conventional anticonvulsanr mcdications except phenytoin and ethosuximide. This letter describes a case of phenytoin intoxication, presumably secondary to ethosuximide. A LO-year-old whire girl. weighing 27 kg, was mcntally retarded with Lennox-Gastaut syndrome. An electrocncephalogram demonstrated mixed seizures with hypsarrhythmia. Absence seizures, which had developed at 16 months of age, had not responded to previous therapy. On admission in March, 1077, she was receiving phenobarbital, 30 mg at bedtime, carbamazepine, 200 mg three rimes a day, phenytoin, 250 mg daily, and methsuximidc, 300 rng twicc a day, and was still experiencing 20 to 30 seizures per week. O n July 12, ethosuximide therapy was initiated at 250 mg daily with subsequent increments and b l d levels as shown in the Table. In October the parient developed anorexia, vomiting, ataxia, and lethargy, all attributed to influenza. Two weeks later the anorexia and vomiting had abated, but the Ietharby and ataxia persisted. Phenytoin and phenobarbital levels were markedly elevated even though the dosage had not been changed. The ethosuximide was reduced, but phr11ytoin blood levels did not decline until that drug was reduced. A SMAC chemistry screen was normal.
Accepted for publication June 26, 1978. Address reprint requests 1 0 Dr Dawson. Idaho Srnre School and Hospital, Box 47, Nmpa, ID 83651.
Notes and Letters
58.)
R. Merikangas, M D
Pseudotumor cerebri, or benign intracranial hypertension, when severe, may be associated with extraocular muscle palsies that result in diplopia. Skew deviation refers to a hypertropia that is not the result of a peripheral neuromuscular lesion or of a local mechanical factor in the orbit [ 11. Clinically, skew deviation is characterized by deviation of one eye above the other, which may be hxed or variable with different directions of gaze. Appropriate muscle testing will distinguish it from palsies of the individual vertically acting extraocular muscles. The following is the first description of skew deviation in pseudotumor cerebri. complained of headA 35-year-old fi,&-handeL{ aches and of episodic occurrence of vertical diplopia consisting of the image in the left eye appearing higher than that in the right. She had learned to compensate for this transient disorder by closing one eye. H e r height was 160 cm and weight, 80 kg. Blood pressure was 1801100 and pulse was 96. H e r only medication was oral conrmceptives. There was no neurological abnormality except upon examination of the eyes. T h e pupils were round, regular, and reactive to light and accommodation with an enlarged blind spot in the visual field of the left eye. Vision was otherwise unimpaired. Papilledema was present bilaterally without gross hemorrhages. The extraocular movements were intact without nystagmus. With further observation, however, while the patient was gazing straight ahead, the right eye deviated vertically upward and maintained that position for a few minutes. Both eyes then reverted spontaneously to scraight-ahead gaze without diplopia until ten minutes later, when the right hypertropia returned and lasted for five minutes. N o headache, visual obscurations, or neurological signs accompanied this episode. She underwent four-vessel cranial aneriography by the femoral route and a C T scan of the brain. These studies revealed no abnormaliry other than a small ventricular system. Lumbar puncture revealed clear, colorless cerebrospinal fluid under a pressure of 550 rnm HaO. There were no microscopic or chemical abnormalities. She was treated with Diamox, Decadron, and glycerol and weekly lumbar punctures until the pressure was normal. After a two-year follow-up period free of medication, there has been no recurrence of skew deviation or any other neurological sign.
Discussion Skew deviation occurred in 8% of neuroophthalmological consultations in the series reported by Keane [31. T h e pathophysiology of skew deviation has not been conchsively determined; however, abnormalities of the brainstem, cerebellum, and structures in the posterior fossa have From the University of Pittsburgh. Western Psychiatric Institute and Clinic, 3811 OH- St. Pittsburgh. PA 15261.
Accepted for publicotion June 20. 1978.
been implicated [I, 31. In 1 0 0 cases analyzed by Keane, two-thirds were associated with brainstem strokes. Pontine damage was most frequent, but midbrain-pretectal and medullary lesions were frequent [3]. It is important to distinguish skew deviation from extraocular muscle palsy secondary to peripheral nerve lesions because of the importance of properly localizing the pathological process. Differentiation from a fourth nerve lesion may be difficult [ 2 ] . Because of these ominous implications, the findings in this patient indicate that pseudotumor cerebri should be included in the differential diaffnosis when skew deviation is discovered. &f~eencg~
1. Cogan DG:Neurology of the Ocular Mudrs. Springfield,IL, Thomas, 1975 2. Gordon D. Sever PS: On the fourth crnnial nerve. lancer
2:466, 1976 3. Keane JR:Ocular skew deviation. Arch Neurol 32:185-l9l),
1975
Serum Phenvtoin after EthosAmide Gary W.h w s o n , PhD, ~ and ~~~~~l~ G.Clark, BS
~
~w. lBrown, , j MD,
Information is available [2] regarding drug-drug interactions for most of the conventional anticonvulsanr mcdications except phenytoin and ethosuximide. This letter describes a case of phenytoin intoxication, presumably secondary to ethosuximide. A LO-year-old whire girl. weighing 27 kg, was mcntally retarded with Lennox-Gastaut syndrome. An electrocncephalogram demonstrated mixed seizures with hypsarrhythmia. Absence seizures, which had developed at 16 months of age, had not responded to previous therapy. On admission in March, 1077, she was receiving phenobarbital, 30 mg at bedtime, carbamazepine, 200 mg three rimes a day, phenytoin, 250 mg daily, and methsuximidc, 300 rng twicc a day, and was still experiencing 20 to 30 seizures per week. O n July 12, ethosuximide therapy was initiated at 250 mg daily with subsequent increments and b l d levels as shown in the Table. In October the parient developed anorexia, vomiting, ataxia, and lethargy, all attributed to influenza. Two weeks later the anorexia and vomiting had abated, but the Ietharby and ataxia persisted. Phenytoin and phenobarbital levels were markedly elevated even though the dosage had not been changed. The ethosuximide was reduced, but phr11ytoin blood levels did not decline until that drug was reduced. A SMAC chemistry screen was normal.
Accepted for publication June 26, 1978. Address reprint requests 1 0 Dr Dawson. Idaho Srnre School and Hospital, Box 47, Nmpa, ID 83651.
Notes and Letters
58.)
