Brainstem auditory evoked responses in infants and children with AIDS.

Brainstem auditory evoked responses were measured in 16 infants and children with acquired immunodeficiency syndrome (AIDS) and in 9 normal infants and children. Two stimulation rates were used: a conventional rate of 10 Hz and a high rate of 50 Hz. Latencies of waves III, IV, and V on the left were significantly longer in the AIDS group when a stimulation rate of 10 Hz was used. With a higher stimulation rate of 50 Hz, significant differences between the two groups occurred in the latencies of waves I, III, and V bilaterally, but there were no significant differences in the interpeak latencies. A measure of the differential effect of the increasing stimulus rate on the two groups was significant for wave I latency and for I-III and I-V interpeak latencies on the left, revealing that increasing stimulation rate prolongs these measures more in the AIDS group. Increased brainstem auditory evoked response stimulation rate may unmask abnormalities in infants and children with AIDS that are not observed when the lower stimulation rate is used.

Reversible myeloneuropathy of nitrous oxide abuse: serial electrophysiological studies.

Detailed electrophysiological studies were performed in 4 patients with myeloneuropathy induced by abuse of nitrous oxide for 1 to 4 years. All presented with paresthesias, weakness, and Lhermitte's phenomena, and exhibited signs of sensorimotor polyneuropathy, ataxia, and arreflexia. Two had subnormal serum vitamin B12 levels. Baseline electrophysiologic testing revealed reduced motor unit potentials, prolonged F wave latencies, absent H reflexes, denervation potentials, and delays in motor and sensory conduction. Three had peripheral and nuchal delay after median nerve stimulation. All were reevaluated after 3 to 12 months' abstinence and treatment with vitamin B12, and all showed substantial clinical improvement. Parallel improvement in electrophysiologic findings occurred, but residual minor conduction delays, loss of H reflexes, electromyographic evidence of denervation, or abnormalities of posterior tibial SEP were noted. These findings confirm the reversibility of myeloneuropathy of nitrous oxide abuse and describe the profile of electrophysiologic recovery in subjects who abstain from further neurotoxic exposure.

L-tryptophan induced eosinophilia-myalgia syndrome.

We describe the spectrum of clinical and histologic abnormalities of 11 women with L-tryptophan induced eosinophilia-myalgia syndrome. The illness is characterized by musculoskeletal symptoms including myalgias, arthralgias and paresthesias. The physical findings consist of muscle tenderness, neuropathies, rash, peripheral and periorbital edema. Electroneurography performed in 10 patients demonstrated a neuropathy in 5 and myopathic changes in 3. Skin and muscle biopsies showed fascial edema, inflammation and perivascular infiltrates in the skin, whereas perineural infiltrates and venulitis were identified in muscle. Seven patients were treated with prednisone; eosinophilia disappeared promptly although myalgias and neuropathy persisted.

Peripheral neuropathy in Crohn's disease patients treated with metronidazole.

Thirteen pediatric patients with Crohn's disease, aged 12-22 yr, were studied to assess the prevalence of peripheral neuropathy due to oral metronidazole. After 4-11 mo of therapy, 11 of 13 patients (85%) had a sensory peripheral neuropathy, determined by abnormal neurologic examinations or reduced nerve conduction velocities, or both. Only 6 of the 11 patients were symptomatic. Nine of 11 patients with peripheral neuropathy had their metronidazole discontinued and 2 had the dose reduced to less than 10 mg/kg X day. Follow-up evaluations of the 9 patients whose metronidazole had been discontinued 5.5-13 mo earlier demonstrated complete resolution of the peripheral neuropathy in 5, improvement in 3, and no change in 1. In the 2 patients whose metronidazole dose was reduced, 1 showed worsening and 1 showed complete resolution of the neuropathy after 10-12 mo of continued therapy.