Journal of Neuro-Ophthalmology, December 1988, Volume 8, Issue 4

Transient cortical blindness with occipital lobe epilepsy.

Three youths with occipital seizures and intermittent visual loss are presented. All three had occipital epileptiform discharges. Visual loss occurred during seizures and improved with anticonvulsant medication. In the absence of an underlying structural lesion of the occipital lobe, occipital seizures in children often respond to antiepileptic medication and may spontaneously resolve. As occipital seizures are often associated with headaches and sometimes with vomiting, differentiating them from basilar migraine may be difficult. The possibility of ongoing seizure activity should be considered in a patient who presents with acute visual loss without an obvious cause.

Journal of Clinical Neuro-ophthalmology 8(4):221-224, 1988, Transient Cortical Blindness with Occipital Lobe Epilepsy Sydney J. Jaffe, M.D., and E. Steve Roach, M.D. © 1988 Raven Press, Ltd" New York Three youths with occipital seizures and intermittent visual 1055 are presented. All three had occipital epilep­tiform discharges. Visual loss occurred during seizures and improved with anticonvulsant medication. In the absence of an underlying structural lesion of the occip­itallobe, occipital seizures in children often respond to antiepileptic medication and may spontaneously re­solve. As occipital seizures are often associated with headaches and sometimes with vomiting, differentiating them from basilar migraine may be difficult. The possi­bility of ongoing seizure activity should be considered in a patient who presents with acute visual 1055 without an obvious cause. Key Words: Epilepsy-Occipital epilepsy-Cortical blindness. From the Department of Neurology, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, NC, U,S.A, Address correspondence and reprint requests to E. Steve Roach, Department of Neurology, 300 S, Hawthorne Road, Winston Salem, NC 27103, U.S,A. 221 Acute cortical blindness is a rare manifestation of seizure activity, as documented by simulta­neous occipital lobe epileptiform activity on elec­troencephalogram (EEG) (1). Occipital lobe epi­lepsy is a focal seizure disorder characterized by positive visual phenomena or transient visual loss. Visual symptoms may occur alone or in conjunc­tion with focal motor or generalized seizure activ­ity. We present three patients with transient corti­cal blindness due to occipital lobe epilepsy and suggest that occipital seizures should be included in the differential diagnosis of acute cortical blind­ness in children. PATIENT 1 This 31-month-old white girl had a 9 month his­tory of daily episodes of momentary conjugate eye deviation to the right, followed by gait ataxia last­ing 15-20 s. By the time of presentation, the epi­sodes had increased in frequency to 8-10 per day. Her physical examination was significant only for bilateral occipito-parietal bruits. Cranial computed tomography (CCT) with intravenous contrast was normal. Her electroencephalogram (EEG) revealed intermittent bilateral occipital spike and wave dis­charges, sometimes with secondary generaliza­tion. At 32 months of age, she was hospitalized in status epilepticus, but did not suffer prolonged hypoxia or acidosis. After intravenous Dilantin, tonic-donic seizure activity stopped, and she re­gained consciousness. A minimal left hemiparesis quickly resolved, but she could not see. Pupillary light reaction and extraocular movements were normal. No retinal, corneal, or lenticular lesions were present. Still blind 3 days later, her EEG showed bilateral occipital spikes. During simulta­neous Videotaped EEG telemetry, intravenous Val­ium was administered. Epileptiform discharges disappeared and her vision returned immediately 222 s. J. JAFFE AND E. S. ROACH after the Valium injection. She was discharged on Dilantin, and has had no further generalized tonic­clonic activity or episodes of visual loss in more than 2 years. She continues to have occasional brief episodes of tonic eye deviation. PATIENT 2 This 7-year-old white girl had a 6-month history of headaches preceded by an aura of flashing lights in her left lower visual field and followed by vom­iting. A diagnosis of migraine was made. She then developed episodic blindness lasting up to 2 min, usually not associated with headache, alteration of consciousness, or obvious seizure activity. How­ever, on one occasion, she was unresponsive for 2 min and upward eye deviation was observed for a few seconds before she resumed awareness and complained of headache. General physical, neuro­logic, and ophthalmologic examinations were com­pletely normal. Specifically, the pupils reacted equally to light and accommodation, extraocular movements were normal, and, between attacks, her visual fields were normal. Her EEG showed 1-2 Hz bioccipital spikes and slow waves (Fig. 1). A subtle left occipital lucency was suspected by CCI, but a lesion could not be confirmed with magnetic resonance scanning. Tegretol (7.5 mg/kg/day) was administered, and all her visual complaints resolved within 1 week. However, she later developed an allergic reaction that necessi­tated stopping the drug. Nevertheless, her epi­sodes of visual loss have now resolved, 2 years later, even without medication; she still has occa­sional headaches. PATIENT 3 This 19-year-old woman had right focal motor seizures which began 5 years earlier, after enceph­alitis. Seizure activity was generally well controlled with antiepileptic medication, but, several times a week, she saw "visual shadows" over both eyes, sometimes progressing to complete blindness last­ing several hours. At age 16, she was hospitalized with focal motor status epilepticus of the right arm and a right homonymous hemianopsia. Seizure ac­tivity has been preceded by "blind spots" for 2 days. Neurologic examination was remarkable for a right hemiparesis. Except for the homonymous hemianopia, no ophthalmologic abnormalities were present. CCT with intravenous contrast was normal. Her EEG showed left occipital epilepti­form activity and generalized slowing. The hom­onymous hemianopia resolved gradually after dis- .' "!,.',,,.,I. Vol. 8. No.4. 1988 12 13 ~--'~_~~~~~;~'-..-.r'~ 14 \..1'\.-"'\, "\ "-I\....~..---''-''.\.~ ...r--..............f''v......./--." ...... J·",~.-\,--...........- ........i·\''''~'\.'''~-./; 15 ! ~ I I .NV\;J:.t\j'\r-"\--4\FV~'i\.rvVJ\/J~\r\V 16 }{\JvJ~~\{\j\I\j/\1f\},NlvV'vjf\J!;\ FIG. 1. EEG of Patient 2 showing bioccipital spike and wave discharge. charge. She was free from focal motor activity, al­though she continued to experience episodic bilat­eral visual loss. One year later, she had a second episode of right focal motor status epilepticus, again preceded by transient patchy visual loss. During her hospitalization, she developed aspira­tion pneumonia and died. Permission for an au­topsy was denied. DISCUSSION These young patients developed transient loss of vision because of occipital lobe seizures. Tran­sient blindness has been described more often as a preictal or postictal phenomenon in association with occipital epilepsy (2-8) than as an ictal phe­nomenon. Gowers (9) was the first to describe blindness as a seizure aura. Ictal blindness has been documented in occipital lobe epilepsy sec­ondary to head trauma (10-12), arteriovenous mal­formation (13,14), occipital lobe metastases (I), oc­Cipital infarction (I), and without apparent etiol­ogy. Temporary visual loss may also follow generalized tonic-clonic seizures or prolonged TRANSIENT BLINDNESS IN OCCIPITAL EPILEPSY 223 complex partial seizures (15). Postictal blindness may be accompanied by a hemiparesis or hemisen­sory deficits (6,14,16). However, if blindness oc­curs in the absence of other postictal symptoms or if previous motor activity was not witnessed, the postictal nature of the blindness may not be recog­nized. Blindness may last only seconds to minutes, as in our second patient, or several days, as in the other two patients. Patient 3 probably had preictal, ictal, and postictal visual loss. Her frequent epi­sodes of impaired vision were most likely the re­sult of seizures, although simultaneous EEG's were not done. The ictal nature of our first pa­tient's blindess was verified by videotaped EEG telemetry, during which the occipital epileptiform discharge and blindness simultaneously resolved with the administration of intravenous Valium. The typical EEG abnormality is occipital spikes, sharp and slow waves (which may be suppressed by eye opening and exacerbated by hyperventila­tion). A videotaped EEG in Patient 1 showed bilat­eral occipital spike and wave discharge, more prominent on the left, and intermittent ocular de­viation to the right. Adversive eye movements, commonly associated with epileptic frontal or tem­porallobe discharge, have also been linked to con­tralateral occipital lobe discharge (1,8,17). Barry et al. (1) described five cases of acute cor­tical blindness or homonymous hemianopia with simultaneous occipital spikes recorded on EEG, a B-year-old girl with a photic-induced bioccipital spike and wave discharge associated with blindess lasting for several minutes. Their other four pa­tients with ictal visual loss were adults 52 to 74 years old. Three of these patients had occipital lobe infarctions, and the other probably had an occipital lobe metastasis. Differentiation of epilepsy from migraine may be difficult (18) as in our second patient. Both epi­lepsy and migraine are paroxysmal disorders. The clinical presentation usually helps to distinguish between the two diagnoses. Consciousness is lost or impaired, often abruptly, in primary general­ized or complex partial seizures. Loss of conscious­ness may also occur in basilar artery migraine (19­21), but is usually slower to develop. Headache may occur before, during, or after a seizure, but most frequently it is a postictal phenomenon. The prodrome in migraine is usually longer than the aura before a seizure (minutes versus seconds). Vi­sual images are more common with classic mi­graine than with seizures. Fortification spectra are a characteristic prodrome in classic migraine, but have not been reported in epilepsy (18). Complete or partial visual loss is a frequent migrainous aura. Ictal hemianopia or blindness, as in our patients, has been described in occipital epilepsy (1,8,10,11,22), but is certainly less common than postictal visual loss (6,14). Basilar artery migraine is believed to result from vasomotor changes in the posterior cerebral circu­lation. A pounding occipital headache is typically preceded by a visual aura or blindness and is ac­companied by signs of brainstem ischemia, such as ataxia, dysarthria, and tinnitus (4,19,20). Camfield et al. (4) described four neurologically normal ad­olescents who had frequent headaches, infrequent seizures, and EEGs characterized by unilateral or bilateral posterior epileptiform discharge. Seizures were easily controlled by antiepileptic medication, although the headaches continued. These authors suggested that seizures were secondary to isch­emic changes in the occipital lobes as a result of multiple headaches. Occipital lobe epilepsy in children has an excel­lent prognosis for both seizure control and even­tual remission (2,23). Occipital epilepsy may be more common than once believed. Recently, Ges­taut and Zifkin (2) described 63 patients with oc­cipital spike and wave complexes. Visual symp­toms are presumed to have occurred in all cases, and consisted of partial or complete visual loss or visual hallucinations. (Those children who were too young to describe their experiences acted as if they could not see or were seeing things that were not there.) The most common postictal complaints were diffuse headache or nausea and vomiting. Ictal blindness or hemianopia, as in our cases, was not mentioned. In this series, seizures occurred in neurologically normal children and were easily controlled by antiepileptic medication, often remit­ting by early adulthood, even after anticonvulsant therapy had been stopped. However, occipital sei­zures may be difficult to control, as in our third patient. The most common cause of acute cerebral blind­ness in children in cerebral hypoxia, usually as a sequela to a cardiorespiratory arrest in a critically ill child (24). Permanent blindness after status ep­ilepticus is presumably from prolonged hypoxia (14). The diagnosis of occipital lobe epilepsy should be considered in the child who presents with acute visual loss without an obvious cause. Occipital epilepsy is suggested by posterior epilep­tic discharges on EEG during a period of blind­ness. 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