Year : 1990 | Volume
: 38 | Issue : 4 | Page : 151--152
Transsynaptic neuronal degeneration of optic nerves associated with bilateral occipital lesions
Mahipal S Sachdev1, Harsh Kumar1, AK Jain1, RK Goulatia2, NK Misra2,
1 Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, Ansari Nagar, New Delhi-110 029, India
2 Department of Neuro - Radiology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi - 110029, India
Mahipal S Sachdev
Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, Ansari Nagar, New Delhi-110 029
A case is reported of a 9-year old male who presented with abnormal behaviour and progressive diminution of vision. Pupils were middilated in both eyes but the pupillary reflexes were preserved. Fundus examination revealed a bilateral optic atrophy and radiological investigations showed a bilateral occipital calcification. We hereby document a case of retrograde transsynaptic neuronal degeneration of the visual system secondary to bilateral occipital lesions. Transsynapptic neuronal degeneration of optic nerves consequent to occipital lobe lesions is a rare phenomenon. Experimentally occipital lobe ablation in non-human primates has been shown to result in optic atrophy. Herein, we document a case of retrograde transsynaptic neuronal degeneration of the visual system secondary to bilateral occipital lesions.
|How to cite this article:|
Sachdev MS, Kumar H, Jain A K, Goulatia R K, Misra N K. Transsynaptic neuronal degeneration of optic nerves associated with bilateral occipital lesions.Indian J Ophthalmol 1990;38:151-152
|How to cite this URL:|
Sachdev MS, Kumar H, Jain A K, Goulatia R K, Misra N K. Transsynaptic neuronal degeneration of optic nerves associated with bilateral occipital lesions. Indian J Ophthalmol [serial online] 1990 [cited 2020 Jan 20 ];38:151-152
Available from: http://www.ijo.in/text.asp?1990/38/4/151/25514
A 9-year old male child presented with complaints of abnormal behaviour for the last 5 years and progressive visual loss of 4 years duration. He had recurrent attacks of episodic alteration of sensorium, consisting of abnormal behaviour, unawareness without involuntary movements or automatism since 4 years of age. One year later, he developed progressive diminution of vision in both eyes first noticed by his school teacher. The visual loss increased gradually and presently he is unable to carry out his daily activities. There was no history of headache, sensory or motor disturbances or endocrinal problems. History of proptosis, diplopia, pain redness, watering, remission or exacerbation of the ocular condition was absent. Systemic examination including neurological assessment was essentially normal. Ocular examination revealed a best corrected vision of 20/200 OU. The pupils were middilated but the light convergence and accommodation reflexes were preserved in both eyes. Direct ophthalmoscopy showed bilateral optic atrophy without blurring of disc margins and normal number of capillaries. There was no evidence of vascular sheathing [Figure 1]. Rest of the ocular examination was non-contributory.
Investigations included routine hematological and biochemical parameters which were normal. Serum calcium, phosphorus and alkaline phosphatase were normal. Titres for rubella, toxoplasma, cytomegalovirus and herpes antibodies were rormal. Serum and cerebrospinal fluid tests for syphilis werre also negative. Interictal electroencephalogram was normal. Plain radiographs of the skull showed bilateral occipital calcifications [Figure 2]. Computerised tomography revealed bilateral high attenuating occipital lesions [Figure 3]. Visually evoked cortical potential latencies of 100 m sec OD and 96m sec OS were within normal limits, while the amplitudes of 3 and 3.2 microvolts were subnormal. [Figure 2][Figure 3]
A diagnosis of complex partial seizures with bilateral optic atrophy due to retrograde transsynaptic neuronal degeneration of the visual neurons was made. The patient was treated with Carbamezapine 200 mgm daily. On follow-up at 4 weeks, seizures were adequately controlled with no change in the visual status.
Diagnosis of transsynaptic degeneration was based on the triad of primary optic atrophy, normal pupillary reflexes and bilateral occipital lobe calcification. Also, no other cause which could explain the bilateral optic atrophy in a young child was found.
Retrograde transsynaptic optic atro l ny has been reported secondary to congenital porencephalic cysts. occipital lobe hematomas, gunshot injury and experimental occipital lobe ablation, ,, In these communications, the occipital lesions were usually bilateral and visual loss followed the initial insult after a latent period of 4 to 6 years. ,,, In another report, no evidence of optic atrophy was found in a 86-year old female, 57 years after unilateral cerebrovascular accident and occipital lobe infarction . Absence of optic atrophy in this case could be explained on the basis of unilateral involvement and that the cerebral insult occurred in adult life when the brain tissue is mature and transsynaptic degeneration unlikely .
In the present case, in conformity with earlier reports,  bilateral occipital lesions were associated with optic atrophy. Complex partial seizures can be explained on the basis of the occipital lesions. In view of the age of onset of visual loss and the usually described latency of 4 to 6 years between the initial insult and optic atrophy, these lesions are likely to be of long duration, possibly congenital.
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