Five patients from a kindred with hereditary hyperekplexia had physiological testing. The surface-recorded electromyographic pattern of audiogenic muscle jerks was identical to that of the normal acoustic startle reflex. Testing at graded stimulus intensities indicated an increase in the gain of the acoustic startle reflex. Nose-tap stimuli resulted in short-latency generalized electromyographic bursts that were similar to the R1 component of the blink reflex. Electrical stimulation of peripheral nerves elicited a pattern of generalized muscle jerks that was similar to that of the acoustic startle reflex. Somatosensory evoked potentials, brainstem auditory evoked potentials, and cortical auditory evoked potentials were normal. The primary physiological abnormality in hereditary hyperekplexia is widespread elevated gain of vestigial withdrawal reflexes in the brainstem and possibly the spinal cord, most likely resulting from increased excitability of reticular neurons.
Lesch–Nyhan syndrome (LNS) is an X‐linked recessive disorder resulting from a deficiency of the metabolic enzyme hypozanthine–guanine phosphoribosyltransferase (HPRT). This syndrome presents with abnormal metabolic and neurological manifestations including hyperuricemia, mental retardation*, spastic cerebral palsy (CP), dystonia, and self‐mutilation. The mechanism behind the severe self‐mutilating behavior exhibited by patients with LNS is unknown and remains one of the greatest obstacles in providing care to these patients. This report describes a 10‐year‐old male child with confirmed LNS who was treated for self‐mutilation of his hands, tongue, and lips with repeated botulinum toxin A (BTX‐A) injections into the bilateral masseters. Our findings suggest that treatment with BTX‐A affects both the central and peripheral nervous systems, resulting in reduced self‐abusive behavior in this patient.
The outcome of stage V Reye's syndrome survivors has not been critically assessed. Three teenage survivors, who initially exhibited severe psychosocial and intellectual regression, are described. Findings support the observation that the neurologic outcome from Reye's syndrome correlates with the duration of altered consciousness during the acute phase. Recovery of intellectual, psychosocial, learning and motor functions is reported. A period of transient dementia was noted, which may be typical in recovery from stage V Reye's syndrome. Unlike other types of encephalopathies, complete resolution may be expected.
A five and a half year old youngster developed cholinergic crisis following the administration of two drops of Phospholine Iodide® 24 hours apart. This response to the medication was followed by variable extraocular muscle measurements. Shortly thereafter a positive Tensilon test and EMG studies confirmed the diagnosis of myasthenia gravis. Treatment consisting of systemic Mestinon® resulted in control of her ocular myasthenic signs. The ophthalmologist should be alert to the possible production of cholinergic crisis in patients highly sensitive to anticholinesterase agents. Myasthenia gravis should be considered as the most probable diagnosis following such an occurrence.
Amantadine hydrochloride (AH) was orally administered to 16 patients with Friedreich9s ataxia. We evaluated patient response with the functional ataxia scoring scale and calculated a total disability score. The mean percent improvement of the total disability score was 29.5%; for ambulatory patients alone it was 45.5%. No significant side effects were encountered. AH appears to be a safe and effective symptomatic treatment of Friedreich9s ataxia.
