Journal of Neuro-Ophthalmology, March 1995, Volume 15, Issue 1

Transient Ictal Cortical Blindness During Middle Age

We report a case of transient ictal cortical blindness in a 63-year-old woman. We reviewed the literature of all seizure-induced bilateral blindness. After careful evaluation of 44 cases, it was evident that the cases could be categorized into three groups with different etiologies, duration of blindness, and probable visual prognosis. Transient cortical blindness may occur with unilateral focal seizure or with bilateral seizure activity of the primary generalized type. Seizure-induced blindness may be ictal or postictal (Todd's) phenomenon or a permanent consequence following status epilepticus. Its duration varies between less than 1 minute to 4 months, or can be permanent. Our case of cortical blindness is related to new onset occipital epilepsy from a left occipital focus, and adds to the evidence that cortical blindness occasionally occurs as an uncommon manifestation of seizure.

Journal of Neuro- Ophthalmology 15( 1): 39- 42, 1995. © 1995 Raven Press, Ltd., New York Transient Ictal Cortical Blindness During Middle Age A Case Report and Review of the Literature Jane M. Joseph, M. D., and Sydney Louis, M. D. We report a case of transient ictal cortical blindness in a 63- year- old woman. We reviewed the literature of all seizure- induced bilateral blindness. After careful evalu­ation of 44 cases, it was evident that the cases could be categorized into three groups with different etiologies, duration of blindness, and probable visual prognosis. Transient cortical blindness may occur with unilateral focal seizure or with bilateral seizure activity of the pri­mary generalized type. Seizure- induced blindness may be ictal or postictal ( Todd's) phenomenon or a perma­nent consequence following status epilepticus. Its dura­tion varies between less than 1 minute to 4 months, or can be permanent. Our case of cortical blindness is re­lated to new onset occipital epilepsy from a left occipital focus, and adds to the evidence that cortical blindness occasionally occurs as an uncommon manifestation of seizure. Key Words: Ictal- Postictal- Cortical blindness- Seizure- Transient- Literature review. Persistent cortical blindness occurs with occipital lobe damage due to infarction, tumor, or trauma. Transient cortical blindness may be a phenomenon of migraine or transient cerebral ischemia. It is rare in seizures and can occur in the ictal and postictal phases especially in children and young adults ( 1). There have been cases in which visual and or neu­rologic deficits were permanent ( 2- 9). Patients with occipital lobe epilepsy may have additional neurologic deficits associated with the seizure such as hemiparesis, deafness, dementia, aphasia, con­fusion, and motor convulsions ( 2,4- 10). We will present a case of an older adult patient who presented with acute transient bilateral blind­ness due to new onset seizures and review the literature. From the Department of Clinical Neural Sciences, Rhode Is­land Hospital, Brown University School of Medicine, Provi­dence, Rhode Island, U. S. A. Address correspondence and reprint requests to Dr. Sydney Louis, Rhode Island Hospital, Physician Office Building Room 428, 593 Eddy Street, Providence, RI 02903, U. S. A. CASE REPORT L. C. is a 63- year- old woman who was admitted for sudden complete blindness. Her past medical history was significant for ankylosing spondylitis, ulcerative colitis, rheumatoid arthritis, osteoarthri­tis, anemia of chronic disease, pyoderma gan­grenosum, and back pain. Her past ophthalmo­logic history was significant for recent cataract sur­gery ( three weeks prior to admission), and chronic uveitis ( 8 years). In July 1993, she developed right eye " blindness" preceded by 1 day of right eye pain and redness. Her right eye was only able to detect hand motion at a distance of one foot. Her left eye had an acuity of 20/ 40. Ophthalmological examination showed increased intraocular pres­sure, conjunctival congestion, and cloudy fibrin­ous material with cells in the anterior chamber within the right eye. She had bilateral superior iris atrophy. A diagnosis of uveitis was made and she was treated topically with pred- forte, timoptic, 39 40 ]. M. JOSEPH AND S. LOUIS and cyclogyl. Her vision improved gradually to an acuity of 20/ 30 by for fourth hospital day. A diag­nostic evaluation for malignancy ( colonoscopy, mammography, abdominal computed tomogra­phy scans, thoracic magnetic resonance imaging, bone scan, chest radiograph, and renal ultra­sound) was unrevealing. Her medications included toradol, Cytotec, prednisone, Prilosec, and enteric- coated aspirin. On the day of admission ( April 1994), she awoke with diffuse visual blurriness, and was able to see only light. In the emergency room, she developed focal seizure activity in the right lower extremity progressing to the right upper extremity before generalizing with loss of consciousness. She was given intravenous Dilantin. She was afebrile with a blood pressure of 179/ 94. Her general medical ex­amination was significant for a 2/ 6 systolic ejection murmer in the left sternal border. Neurologically, she was somnolent but was easily arousable. She followed simple commands and moved all four ex­tremities spontaneously. She did not blink to threat. There was no light perception in either eye. There were normal pupillary light reflexes. Fundu-scopic examination revealed macular drusen and was otherwise normal. She had bilateral extensor plantar reflexes. She had a bitten tongue. The re­mainder of her examination was unremarkable. Laboratory tests included a normal head ( non-contrast) computed tomography scan and cerebro­spinal fluid examination. Abnormal laboratory tests included white blood cell count of 19.3 K/| xl, a platelet count of 721 K/| xl, a hemoglobin of 12.2 g/ dl, elevated urinary protein (> 300 mg/ dl), a so­dium of 128 mEq/ L, chloride of 86 mEq/ L, blood glucose of 194 mg/ dl and ESR at 100 mm/ h. Other electrolytes, PT, PTT, and EKG were unremark­able. Examination on hospital day 1 was significant for improved mental status. She was alert and ori­ented to person, place, and had fluent speech. Writing was intact, but her reading ability was dif­ficult to assess. She did not have finger agnosia, neglect, or gaze preference. She could name col­ors. She did not blink to threat but was aware of hand movement. She could not consistantly count fingers at 2 ft. The rest of her examination was unchanged. Later that afternoon, she was able to count fin­gers in all quadrants and identify parts of the ex­aminers face. She was unable to identify the exam­iners bow tie or its color. Her vision was noted to be 20/ 800 bilaterally. By her second hospital day, her vision had im­proved significantly. She was able to count fingers consistantly in all quadrants at a distance of 2 ft. The rest of her examination was unremarkable. By her third hospital day, her visual acuity was nor­mal with intact visual fields. Additional diagnostic exams were performed. An EEG ( day 3) showed almost continuous runs of spikes lasting 30- 60 seconds in the left occipital region. On occasion, this activity spread to involve the entire left hemisphere and, rarely, the poste­rior aspects of both hemispheres. An echocardio­gram was negative for valve disease, or mural thrombus. Gadolinium- enhanced MRI of the head, carotid duplex, transcranial Doppler ultrasound, and abdominal and chest radiographs were all negative. She was maintained on Dilantin for seizure con­trol and steroids for control of her ulcerative colitis. On day 8, the patient was transferred another hospital to be closer to her family. DISCUSSION Cortical blindness is a consequence of dysfunc­tion or destruction of area 17 in both occipital lobes. The degree of visual loss can vary from sub­tle visual field deficits to complete visual loss with no light perception. There is a loss of reflex closure of the eyelids to bright light or to threat. The visual fibers that terminate in the midbrain are intact and therefore allow the preservation of the light reflex. There is full ocular motility. Opticokinetic nystag­mus is absent. The funduscopic examination is normal. Permanent destruction of the occipital cortex is most commonly seen in posterior cerebral artery occlusion associated with vertebrobasilar disease. More infrequently, trauma or tumor may cause such destruction. If the lesion extends beyond the striate cortex into the visual association area, pa­tients who are unable to see may deny blindness. This is known as visual anosognosia or Anton's syndrome. Transient cortical blindness can be produced by migraine, seizure, or transient cerebral ischemia. Occipital blindness is an unusual manifestation of occipital lobe seizure commonly presenting with elementary visual hallucinations. Reported etiolo­gies for seizure- induced blindness have included malaria ( 5), viral encephalitis ( acute and chronic) ( 4), porphyria ( 11), anoxia ( 5), embolic stroke ( 4), malignancy ( 2,4), infarction ( 2,12), MEL AS ( mito­chondrial myopathy, encephalopathy, lactic acido­sis, and strokelike syndrome) ( 3,13), subacute scle­rosing panencephalitis ( 4), head trauma ( 12,14,15), / Neuro- Ophthalmol, Vol. 15, No. 1, 1995 TRANSIENT ICTAL BLINDNESS 41 arteriovenous malformation ( 4,16), cerebral vascu­lar spasm and ischemia ( 11), and idiopathic sei­zures ( 2,6- 9,12,17- 20). Our case represents ictal and possibly postictal cortical blindness as a consequence of a left occip­ital seizure. A literature review on this subject yielded 44 patient descriptions ( 1- 9,12,13,17- 20) in which blindness was associated with seizures. In addition, Williamson ( 21) indicated they had seen 10 cases of ictal amaurosis but the details of these cases were unavailable. Review of the 44 case his­tories in the literature permits subdivision of the patient grouping into three major categories.: 1. In the first group, patients had a long suc­cession of seizures, or status epilepticus, and de­veloped blindness, which was permanent or per­sisted for many months ( 4- 9). It seems likely that the prolonged or permanent visual loss in these patients is probably caused by cellular damage ei­ther due to prolonged neuronal firing or, as sug­gested in many articles, by anoxia or ischemia on a variety of bases. Of the 44 cases, 15 fell into this category. All of these patients were under 12 years of age. 2. In the second group, patients had bilateral occipital, atypical spike and wave activity, present during the seizure, resulting in bilateral blindness. This appeared to be an atypical variant of general­ized spike and wave activity of the absence type. In these cases, blindness is present ictally in asso­ciation with bilateral bursts or persistant spike and wave activity in the occipital lobes. In one patient, photic stimulation reproduced the blindness with associated occipital spike and wave activity. Such episodes have also been recorded on video EEG telemetry ( 2). Ten patients fell in this group ( 2,4,12,17- 20). The majority of these patients were 10 to 20 years of age, with three exceptions. The duration of blindness was between minutes to less than half an hour. 3. In the third group, patients had a focal sei­zure that originated in or was adjacent to either the left or right occipital lobe ( 2- 4,12,13,18). Interictal EEGs in these patients demonstrated unilateral fo­cal spikes. Ictally, the seizure activity spreads to both occipital lobes and sometimes toward the temporal and parietal lobes on the originating side. There were 18 patients in this group. These pa­tients ranged from 7 to 74 years of age with a slightly heavier preponderance in the older age groups. Focal pathology was found in some of these cases. The blindness in these patients was either ictal or postictal. In several patients, the blindness was the major manifestation of the sei­zure without associated convulsions. In some, the episodes were prolonged and represented partial nonconvulsive status epilepticus of the occipital lobes. In two of these patients, visual improve­ment occurred but permanent field defects re­mained ( 2,3). Although the literature refers to preictal blind­ness, it seems that this is a misnomer and that the blindness is in fact a consequence of a partial oc­cipital seizure spreading to the contralateral side. This has been demonstrated to occur with EEG video telemetry by Barry and colleagues ( 2) and by Penfield and Erickson ( 22) using cortical stimula­tion. Each demonstrated involvement of the con­tralateral side in the absence of impaired con­sciousness. These symptoms may or may not progress to more classical seizures. Seizure activity from the occipital cortex often spreads forward to the temporal lobe, resulting in a partial complex seizure, or to the parietal and posterior frontal lobe, resulting in motor seizure activity on the side of the original focus ( 1). Generalized seizures may follow as in our patient. The other form of ictal blindness is that which is produced by occipital spike and wave activity. It may occur in short sei­zures or may also occur as a form of nonconvulsive status epilepticus. Postictal blindness may follow any of the above types as a Todd's phenomenon ( 23). This is usually of short duration lasting less than 30 minutes after the seizure but can rarely last an hour or more. As discussed in the literature, it is probably the result of active inhibition rather than neuronal exhaus­tion ( 10,24). More prolonged or permanent postic­tal blindness may occur following convulsive sta­tus epilepticus. It has been postulated to be due to occipital lobe anoxia ( 5,25). Other explanations given in the literature include posterior cerebral artery spasm ( 11), which seems improbable. More probable is that the permanent damage is a conse­quence of the sustained status and results from the prolonged excitation of neurons. Prolonged sus­tained seizure activity may result in permanent damage to the convulsing area, as in the case of Aldrich and Vanderzant ( 3). Our case of cortical blindness is related to new onset occipital lobe seizures. The precise etiology in our patient was not determined. It may well have resulted from a small infarct or tumor in the left occipital pole, but this was not visible on an MRI scan. REFERENCES 1. Salanova V, Andermann F. 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