Visual evoked responses in ethambutol induced optic neuritis.

Pattern evoked responses were recorded in 46 patients of tuberculosis on ethambutol and 16 healthy subjects. Deterioration in visual acuity was documented in two patients (4.3%). P100 latency was delayed in 16 cases (34.8%), while in 12 patients (26.1%) both latency and amplitude were affected. A cut off latency value of > or = 140 ms was associated with ophthalmological findings. The incidence of subclinical toxicity as detected by visual evoked response (VER) was higher in older subjects, patients on higher doses of ethambutol (> or = 20 mg/kg/day) and longer duration of treatment. Of two cases with objective ocular signs, one who reported for follow up after two months had recovered completely after stopping ethambutol. Recording of VER is an extremely useful objective test for subclinical optic nerve damage.

Isoniazid induced neuropathy in slow versus rapid acetylators: an electrophysiological study.

Clinical, biochemical and nerve conduction studies were performed in 100 cases of tuberculosis taking isonicotinic acid hydrozide (isoniazid) for more than 12 weeks. Electro-physiological studies were carried out in a similar number of normal age and sex matched controls. In 16 percent of cases an abnormality was documented in the motor nerve conduction velocity, amplitude and terminal latency of the common peroneal, ulnar and median nerves; of these, only two patients had objective evidence of neuritis. The occurrence of isoniazid neuropathy was found to be more in the fourth decade of life (10 of 16), in those who had taken the drug for over six months (13 of 16), and in 'slow' inactivators (10 of 16).

Contrast computed tomography in epilepsy with special reference to intracranial ring or disc enhancing lesions.

We report the results of computed tomography (CT) in 170 patients who developed seizures. Localized signs could be demonstrated by neurologic examination in 23.5%. CT findings were normal in 64 patients (37.6%). The commonest abnormality was a focal ring or disc enhancing lesion in 66 patients (62.3%) followed by calcification (18 patients; 16.9%), cerebral atrophy (9; 8.5%), vascular lesions (7; 6.6%), tumours (4; 3.8%) and congenital hydrocephalus (2; 1.9%). The occurrence of abnormal CT was higher (74.3%) in patients with partial seizures.

A prospective study of 14 cases of motor neuron disease.

Fourteen consecutive patients with motor neuron disease were studied during a period of one year. Seven patients were in the second decade of life, with eleven below the age of 40 years. Males accounted for 13 cases. Four had sustained some trauma in the past, one had poliomyelitis. Younger patients (average age 17.9 years) usually had an asymmetrical lower motor neuron lesion which was gradually progressive (the Norris score reached an average of 89.9 in a mean period of 36.9 months). A largely symmetrical distribution affecting both the upper and lower motor neurons and the lower cranial nerves with a rapidly downhill course (the Norris score fell to 80.3 in 12.9 months) were the features observed in older patients (average age 46.7 years). Cerebrospinal fluid protein was raised in four cases. Anti-neural antibodies were not demonstrable in any of the patients.

Clinical profile and electrodiagnostic study of peripheral neuropathy.

A clinical analysis and electrophysiological study was performed in 40 cases of peripheral neuropathy. Motor nerve conduction velocity (MNCV) and electromyography (EMG) were also recorded in 20 healthy volunteers. Twelve cases were of diabetic neuropathy (DN), nine of Guillain-Barre syndrome (GBS), eight of idiopathic, six of leprous, three of toxic neuropathy and one each of acute intermittent porphyria (AIP) and carcinomatous neuropathy. The onset was insidious in a majority of the cases (70%), the presenting symptom being paraesthesia (27.5%). A variable sensory loss was the commonest finding (77.5%). Two patients each had evidence of cranial nerve involvement and affection of urinary bladder and bowel. In both DN and GBS there was a significant reduction in the MNCV especially in the peroneal nerves. In DN 41.6% had evidence of decreased motor unit potentials and 16.6% showed spontaneous fibrillatory activity. For GBS these figures were 77.7% and 8.3% respectively. The peripheral nerve involvement was variable in leprosy and the EMG was normal in all, but one case.