To investigate the diagnostic validity of electromyography in the hypotonic infant, 79 children aged 0 to 12 months, seen over a 20-year period, were studied retrospectively. The diagnoses using ...clinical, muscle biopsy, and laboratory characteristics were: 25 central hypotonia, 20 spinal muscular atrophy, 20 myopathy, four myotonic dystrophy, four benign congenital hypotonia, two congenital muscular dystrophy, two myasthenia gravis, one infantile inflammatory myopathy, and one arthrogryposis multiplex congenita. Using strict criteria, electromyography accurately predicted the final diagnosis in 65% of infants with spinal muscular atrophy and was consistent with the diagnosis in another 25%. In contrast, electromyography accurately predicted the final diagnosis in only 10% of infants with myopathy and was normal in 88% of infants with central hypotonia. In infants with spinal muscular atrophy, there was no difference in the predictive value of electromyography when performed in the newborn compared to older infants. Normal distal nerve conduction velocities in infants with spinal muscular atrophy may predict prognosis, since these infants had a longer survival. Electromyography thus has a high predictive value for infantile spinal muscular atrophy but not for myopathy.
The clinical picture, family history, laboratory data, treatment modalities, and outcome in 27 juvenile myasthenics seen over a 25-year period are presented. Onset was after 10 years of age in the ...majority of patients. Half presented with ocular signs, the other half with generalized-onset myasthenia. Half of those with ocular-onset myasthenia progressed to generalized myasthenia. The female-to-male ratio was 3.5:1. Myasthenia gravis was reported in the mother of one patient. Ptosis was the most common presenting sign. It was unilateral at onset in 33% of patients and remained unilateral in 11%. Pharmacologic tests (neostigmine methylsulfate and edrophonium chloride) were positive in 92% of patients. Serology was positive in 63%, whereas repetitive nerve stimulation was positive in 33% when distal nerves were stimulated and in 66% when proximal and distal nerves were stimulated. Seropositivity tended to increase with generalization of the myasthenic process. No statistically significant difference in seropositivity was noted between males and females. Anti-striated muscle antibodies were detected in two patients, neither of whom had thymoma. The yield of repetitive stimulation increased with generalization of the myasthenic process and when proximal nerves were stimulated. No statistically significant difference was noted in the decremental response between seropositive and seronegative patients. The majority of ocular myasthenics were treated with pyridostigmine bromide monotherapy. With generalization of the myasthenic process, other modes of medical and surgical therapies were needed. All patients given corticosteroids ultimately underwent thymectomy. The mean age at presentation and the duration of symptoms at presentation were longer in thymectomized patients than in those without thymectomy.
Cerebellar hypoplasia is found in association with a variety of neurologic and systemic disorders. It is the primary finding in the uncommonly reported condition of autosomal recessive cerebellar ...hypoplasia. We describe two siblings with cerebellar hypoplasia documented in both by magnetic resonance imaging (MRI) and review the clinical features of previously reported cases of autosomal recessive cerebellar hypoplasia. The most common findings in this disorder are nonprogressive ataxia, strabismus, mental retardation, and speech delay with dysarthria. Previously reported cases have been confirmed by autopsy, pneumoencephalography, or computed tomographic (CT) scans. MRI clearly documents diffuse cerebellar hypoplasia and aids in distinguishing autosomal recessive cerebellar hypoplasia from other disorders. The pathophysiology of this disorder is uncertain, however, studies of the weaver mutant mouse (an animal model of autosomal recessive cerebellar hypoplasia) suggest that an abnormality of the Bergmann glia may lead to the observed granule cell layer deficiency in these patients. This diagnosis should be considered for children with nonprogressive ataxia and families should be made aware of the 25% recurrence risk.
Two patients with seizure-associated miosis and ptosis are described. In both there are magnetic resonance imaging abnormalities of the temporal lobe. In one patient, increased magnetic resonance ...imaging signal intensity is present in the temporal lobe contralateral to ptosis and miosis. In the other, there is temporal lobe asymmetry with the smaller temporal lobe ipsilateral to the miotic pupil and ptotic lid. The relevant human and experimental literature related to cortical control of pupil size and lid movement is reviewed. Based on the available literature and the findings in these two patients, it is proposed that the increased signal intensity in the temporal lobe of one patient represents an irritative stimulus causing contralateral miosis and ptosis, whereas the temporal lobe hypoplasia in the second patient permitted impulses from the contralateral normal temporal lobe to predominate, resulting in miosis and ptosis homolateral to the hypoplastic temporal lobe.
Three cases with rare association of neurofibromatosis, hydrocephalus, and aqueductal stenosis seen at the University of Iowa during the past 20 years are presented. The literature on nontumoral ...hydrocephalus and aqueductal stenosis in neurofibromatosis is reviewed. Possible explanations for the association of aqueductal stenosis and neurofibromatosis are discussed. It is concluded that aqueductal stenosis, though not common, should nevertheless be considered in the differential diagnosis of hydrocephalus in neurofibromatosis.
Facial nerve palsy has long been considered to have an infectious etiology. Recent diagnostic analyses in children and adults have provided convincing evidence that reactivation of varicella-zoster ...virus (VZV), sometimes during infectious mononucleosis, can lead to cranial nerve VII palsy. The site of reactivation from latency is the geniculate ganglion. Virus most likely enters the ganglion during chickenpox, via the sensory branches of the facial nerve located on the ear and tongue. Retrospective reviews suggest that patients with VZV-related facial nerve palsy have poorer outcomes than other cases of Bell's palsy. Therefore treatment with acyclovir is suggested when VZV reactivation i slikely.
