M. Lo Monaco

Ocular myasthenia: diagnostic and therapeutic problems

ABSTRACT— Forty‐eight patients with purely ocular myasthenia were studied. Tensilon test was positive in 46 patients (95%); decremental response from limb muscles was present in 24 patients (50%); anti‐AChR antibodies were detected in 20 patients of 44 (45.5%). Tweny‐two patients underwent thymectomy, 18 were given corticosteroids, 42 received AChE drugs. At the end of the observation period, 8% of the patients were in remission, 67% were improved, 25% were unchanged. In our experience, the diagnosis of ocular myasthenia relies mainly on clinical data; AChE drugs are not very effective in extrinsic ocular muscles; indications for thymectomy should be restricted to thymoma cases and, perhaps, to patients in the early stages of the disease, within the first year of onset; corticosteroids are effective in most cases, but relapses after withdrawal are not uncommon.

Ocular palsies in the absence of other neurological or ocular symptoms: analysis of 105 cases.

Abstract We studied prospectively 105 unselected patients complaining of ptosis and/or diplopia due to extrinsic ophthalmic muscle palsies without other neurological signs. All patients underwent the same diagnostic protocol. The presenting symptoms were: ptosis, 35 patients (33%); diplopia, 27 patients (26%); ptosis and diplopia, 43 patients (41%). The oculomotor nerve was most frequently involved, followed by the abducens nerve. The final diagnoses were: ocular myasthenia, intracranial and/or orbital pathology, thyroid ophthalmopathy, diabetic ophthalmoplegia, mitochondrial myopathy, oculopharyngeal muscular dystrophy. In 26 patients (25%) the cause remained undetermined. Our study confirms the difficulty of establishing an aetiological diagnosis in patients with isolated ocular palsies.

Early-onset myasthenia gravis: clinical characteristics and response to therapy

We studied 59 children with myasthenia gravis (MG). Disease onset was pre-pubertal in 26 patients and post-pubertal in 33. The male to female ratio was 0.62 in the early- and 0.17 in the late-onset groups. The frequency of ocular MG was higher in patients with prepubertal onset. Patients with generalized MG generally showed a good response to thymectomy and corticosteroid therapy proved effective with no major side-effects. In our experience early-onset MG has the same course as in adult life. We recommend thymectomy for generalized disease in childhood, except in very young children on account of possible long-term effects on immunological development. Immunosuppressive therapy should be considered in severely affected patients who do not respond adequately to other therapies.

Multiple paraneoplastic diseases associated with thymoma

Here we report a patient with a lymphoepithelial thymoma who developed in chronological sequence limbic encephalitis, neuromyotonia and myasthenia gravis. The patient presented with limbic encephalitis associated with an invasive thymoma and improved after surgery and cytotoxic therapy. Two months after thymectomy, neuromyotonia associated with hyperhidrosis and mild motor neuropathy occurred and the patient was given plasma-exchange and prednisone therapy. Five months later he developed mild generalised myasthenia gravis. Anti-acetylcholine receptor antibodies, previously repeatedly negative, were found positive at the onset of clinical signs of myasthenia gravis.

Peripheral neuropathy with hypomyelinating features in adult-onset Krabbe's disease

We describe three brothers suffering from Krabbes disease with onset in the fifth decade. The proband showed a complete deficiency of leukocyte enzyme galactocerebrosidase and was found to be heterozygous for two previously described mutations: G > A809 and 502T/del consisting of a 30 kb deletion. In all three brothers the neurological examination showed features of asymmetrical peripheral neuropathy associated with pyramidal signs and the electrophysiological examination showed a generalized slowing of nerve conduction velocities. Two patients died at 59 and 61 years of age due to respiratory failure. Both the proband and his brother underwent a sural nerve biopsy. In the former the most striking finding was the presence of uniformly thin myelin sheaths without evidence of demyelination; a complete absence of fibers was found in the latter. Our findings confirm that peripheral neuropathy may be the presenting feature of late-onset Krabbes disease. Hypomyelination rather than demyelination may represent the distinguishing pathological finding of this condition.

Usefulness of segmental and comparative tests in the electrodiagnosis of carpal tunnel syndrome: the Italian multicenter study

Abstract The Italian CTS Study Group performed a wide multicentric and multiparametric study to quantify the increase of electrodiagnostic sensitivity using an extended neurophysiological protocol and particularly segmental and comparative tests. The study also evaluated the clinical features of carpal tunnel syndrome (CTS) diagnosed by these tests, using validated physician- and patient-oriented measurements. The study group was composed of 740 patients for a total of 1123 idiopathic CTS hands. Overall, the sensitivity of standard tests (median digit-wrist sensory conduction velocity and wrist-thenar distal motor latency) was 83.5%. Comparative/segmental tests disclosed abnormal findings in a further 11.4% of cases, providing CTS electrodiagnosis in about 7 of 10 “standard negative” cases. The overall sensitivity of the electrodiagnostic protocol was 94.9%. The CTS population diagnosed by segmental/comparative tests had a clinical picture characterized by a high percentage of pain, and severe discomfort but no limitation in functional daily activity. Our data confirm the usefulness of a complete neurophysiological assessment by using segmental/comparative tests when standard tests yield normal results.

Autosomal recessive hypermyelinating neuropathy

We studied three patients from two kinships, affected by early onset hereditary motor and sensory neuropathy with probable autosomal recessive inheritance (HMSN type III). Morphological studies of sural nerve biopsies revealed an abnormal myelin proliferation. Two adult patients with long-term follow up, lost ability to walk at 28 and 22 years and showed severe involvement of the cranial nerves. Our observations suggest that “hypermyelination neuropathy” with early onset is a progressive disease with poor long-term prognosis. In one kinship the occurrence of the disease in two sibs of both sexes but not in parents, is consistent with an autosomal recessive inheritance. Familial cases of hypermyelination neuropathy have not been described in previous reports. Morphological aspects of this condition are compared with other forms of hypermyelination neuropathy.

Peripheral neuropathy is a common manifestation of mitochondrial diseases: a single-centre experience

Peripheral neuropathy in mitochondrial diseases (MDs) may vary from a subclinical finding in a multisystem syndrome to a severe, even isolated, manifestation in some patients.

Carpal tunnel syndrome : Neurophysiological results of surgery based on preoperative electrodiagnostic testing

Fifty-three hands with carpal tunnel syndrome had pre- and postoperative evaluations of median nerve distal motor latency (from wrist to thenar muscles) and orthodromic sensory nerve conduction velocity (from thumb and middle finger to wrist). At 6 months we observed a neurophysiological return to normal in all cases with normal preoperative distal motor latency and in about 50% of the hands with preoperative distal motor latency between 4 and 6 ms. Prolongation of the distal motor latency over 6 ms was not followed by return to neurophysiological normality, although some degree of sensory function was restored in the majority of cases.

Italian multicentre study of carpal tunnel syndrome: clinical-neurophysiological picture and diagnostic pathway in 461 patients and differences between the populations enrolled in the northern, central and southern centres

Abstract The economic trend in our country, as in other countries, now requires us to pay more attention to the social and economic aspects of health. Therefore, it is important to evaluate the diagnostic pathway and the socio-economic aspects of pathologies.The Italian CTS Study Group performed a wide multicentre and multidimensional study (through a patient-, physician- and neurophysiologically oriented evaluation) on 461 idiopathic CTS patients to evaluate the clinical-neurophysiological picture and the diagnostic pathway. The whole population and the differences between the populations enrolled in the neurophysiological centres of the northern, central and southern parts of Italy were analysed.This study provided new and interesting information. As concerns the whole population, we observed different diagnostic pathways in relation to the level of schooling. As concerns the comparison of the populations, the southern centres have a population of CTS patients with higher frequency of hand stress and more severe nerve impairment.