Chiasmal arachnoiditis as a manifestation of generalized arachnoiditis in systemic vascular disease. Clinico-pathological report of two cases.

Its aetiology and pathogenesis have, however, remained controversial, and there is no agree- ment whether it is a specific entity or the manifestation of a more generalized disease of the meninges.One reason for this appears to be the lack of histopathological examinations, since the disease is not usually fatal.Only five cases have been reported in the literature with pathological studies (Davis and Haven, 1931; Bollack, David, and Puech, 1937b).Two additional cases are described in this report with clinico-pathological evidence and an attempt has been made to elucidate the pathogenesis of the syndrome.Case Reports Case 1, a woman aged 22 years, was admitted to the ophthalmological department of our hospital for the first time in June, 1950, with acute deterioration of the visual acuity of the left eye, ptosis of the left eyelid, and left hemifacial pain of 10 days' duration.Physical Examination.-Therewas ptosis of the left upper eyelid and limited movements of the left eyeball due to paresis of all the extra-ocular muscles except the superior oblique and medial rectus.The left pupil was larger than the right with a sluggish reaction to direct light but a good consensual response.Hertel's exophthalmometry showed slight proptosis of the left eye (2 mm.).Visual acuity was 6/6 in the right eye, but was restricted to counting fingers at a distance of 1-5 m. in the left.The right visual field and fundus were normal.The left visual field showed a nasal and central defect (Fig. 1, overleaf) and there was papilloedema of 1 diopter with marked venous congestion.There was hyperalgesia in the distribution of all three divisions of the left trigeminal nerve.Blood pressure was 115/85 mm.Hg, and the general condition of the patient was good.Laboratory Investigations.-Erythrocytesedimentation rate 20 mm. in the 1st hr (Westergren), Hb 75 per cent., RBC 4,550,000/cmm., white cell count 8,300/cmm.with a normal differential count.Blood sugar 97 mg. per cent.Urea 32 mg.per cent.Wassermann reaction negative.The urine contained traces of albumin and occasional white blood cells.X rays of the skull, orbits, optic foramina, sinuses, and chest were all normal.Left common carotid arteriography was normal.Progress.-After 3 weeks of treatment with penicillin, the pains in the distribution of the left trigeminal nerve, the ptosis, and the paresis of the extra-ocular muscles disappeared, but the visual acuity and field defect in the left eye remained unchanged.There was regression of the papilloedema, but evidence of optic atrophy was noted for the first time.Follow-up examinations over a period of 8 months revealed only increase of the optic atrophy.