Study of evolution of nerve damage in leprosy. Part II--Observations on the index branch of the radial cutaneous nerve in contacts of leprosy.

A total of 35 contacts from 20 families of lepromatous index cases were screened clinically. All of them were subjected for nerve conduction velocity (NCV) studies of both left and right index branch of the radial cutaneous (IRC) nerve. Fifteen of these nerves were biopsied. Out of 15 IRC nerves biopsied 10 had slightly reduced average NCV values and 5 were normal. Four nerves out of 10 where average NCV was reduced and 1 nerve out of 5 where NCV was normal showed significant ultrastructural changes and higher percentage of segmental demyelination (10%--13%). There was a striking similarity between the changes seen in the IRC nerves of early cases of leprosy and of contacts.

Study of the evolution of nerve damage in leprosy. Part I--Lesions of the index branch of the radial cutaneous nerve in early leprosy.

A total of six index finger branch of the radial cutaneous (IRC) nerves from three BL, two BB and one BT cases of leprosy, with less than 6 months history of disease were subjected for nerve conduction velocity (NCV) studies followed by biopsy. The biopsy was divided into three parts and subjected for light microscopy quantitative histology, electron-microscopy and fibre tease studies. The nerves revealed a slight reduction in NCV and a varying degree of segmental demyelination ranging from 10% to 35%. The earliest changes observed were the thickening and proliferation of Schwann cell processes of the unmyelinated fibres and degeneration of their axons regardless of the type of leprosy.

Study of the evolution of nerve damage in leprosy. Part I--Lesions of the index branch of the radial cutaneous nerve in early leprosy / Study of evolution of nerve damage in leprosy. Part II--Observations on the index branch of the radial cutaneous nerve in contacts of leprosy

A total of six index finger branch of the radial cutaneous (IRC) nerves from three BL, two BB and one BT cases of leprosy, with less than 6 months history of disease were subjected for nerve conduction velocity (NCV) studies followed by biopsy. The biopsy was divided into three parts and subjected for light microscopy quantitative histology, electron-microscopy and fibre tease studies. The nerves revealed a slight reduction in NCV and a varying degree of segmental demyelination ranging from 10% to 35%. The earliest changes observed were the thickening and proliferation of Schwann cell processes of the unmyelinated fibres and degeneration of their axons regardless of the type of leprosy. A total of 35 contacts from 20 families of lepromatous index cases were screened clinically. All of them were subjected for nerve conduction velocity (NCV) studies of both left and right index branch of the radial cutaneous (IRC) nerve. Fifteen of these nerves were biopsied. Out of 15 IRC nerves biopsied 10 had slightly reduced average NCV values and 5 were normal. Four nerves out of 10 where average NCV was reduced and 1 nerve out of 5 where NCV was normal showed significant ultrastructural changes and higher percentage of segmental demyelination (10%--13%). There was a striking similarity between the changes seen in the IRC nerves of early cases of leprosy and of contacts.

Teased fibre study of early nerve lesions in leprosy and in contacts, with electrophysiological correlates.

A teased fibre technique was used to study 19 biopsies of the index finger branch of the radial cutaneous nerve of leprosy patients and contacts. These were compared with four normal nerves. Five nerves were from patients with preclinical nerve lesions, five from leprosy patients with minimal sensory nerve impairment, and five from contacts of lepromatous leprosy. The extent of demyelination in preclinical nerve lesions in leprosy and in contacts of leprosy is recorded. The usefulness of nerve conduction velocity studies in early leprosy patients and in contacts is discussed.

Teased fibre study of early nerve lesions in leprosy and in contacts, with electrophysiological correlates

A teased fibre technique was used to study 19 biopsies of the index finger branch of the radial cutaneous nerve of leprosy patients and contacts. These were compared with four normal nerves. Five nerves were from patients with preclinical nerve lesions, five from leprosy patients with minimal sensory nerve impairment, and five from contacts of lepromatous leprosy. The extent of demyelination in preclinical nerve lesions in leprosy and in contacts of leprosy is recorded. The usefulness of nerve conduction velocity studies in early leprosy patients and in contacts is discussed.

The syndrome of continuous muscle fiber activity. Evidence to suggest proximal neurogenic causation.

Four patients with the syndrome of continuous muscle fiber activity were seen in a period of 6 years. Young females predominated. Remarkable improvement followed phenytoin sodium and carbamazepine administration in three patients, one of whom was "cured" within 4 years. In the remaining patient the response was inconstant. Electromyography showed abnormal spontaneous activity with diphasic and triphasic potentials appearing as doublets and multiplets. Waxing and waning was observed. D-tubocurarine and succinylcholine abolished the spontaneous activity excluding the muscle and the myoneural junction as its source. Spinal anesthesia, thiopental sodium, sleep and baclofen had no effect on it, ruling out a central source. In three patients, nerve blocks at the knee and elbow or wrist abolished this activity pointing to a proximal site of origin in the nerve somewhere between the spinal cord and the nerve block. In the remaining patient such a block significantly reduced but did not abolished the activity suggesting a dual source above and below the block. Finally successive examinations in one of our patients led us to believe that this activity may arise from different sites at varying times. It appears that regardless of the site of origin of the activity in the motor axon the counter part clinical syndrome remains the same.

Electromyography in nutritional osteomalacic myopathy.

Electromyographic studies in 15 women with nutritional osteomalacia and proximal muscle weakness showed brief duration motor unit action potentials of normal amplitude and increased proportion of polyphasic motor unit potentials in the majority of them. By employing quantitative methods of electromyography, more positive results were obtained, thus reducing the sampling data. The histology showed non-specific muscle fibre atrophy without degenerative changes and the clinical and electromyographic examinations together showed clear evidence of a myopathy, suggesting a reversible transient block of the muscle fibres. Contrary to a recent suggestion, the nature of muscular change in osteomalacia remains the same regardless of its cause being nutritional or otherwise.

Quantitative, histologic and ultrastructural studies of the index branch of the radial cutaneous nerve in leprosy and its correlation with electrophysiologic study.

A correlative study of clinical, electrophysiological, quantitative, histopathologic and ultrastructural changes seen in 13 instances of the index branch of the radial cutaneous nerve was undertaken in leprosy patients. Testing by graded nylon proved to be more reliable than any other conventional clinical tests. The quantitative studies revealed that small-sized fiber loss was encountered in the early stages of nerve involvement in leprosy followed by loss of large-sized fibers with or without increase in small-sized fibers. Segmental dymyelination of small-sized fibers was seen in early stages of degeneration in leprosy nerves irrespective of type of leprosy. Wallerian degeneration was encountered in advanced stages with total destruction of the nerves. At the ultrastructural level clinically normal nerves of leprosy patients (LN series) showed minimal but significant changes, such as thickening of the basement membrane of perineurial cells, as well as an increase in the amount of collagen between the perineurial layers. Marked increases in the amount of endoneurial collagen were noticed. Axons devoid of myelin, probably demyelinated fibers, were occasionally observed. Slight proliferation of the basement membrane of the endothelial cells was also observed. These changes were of a more advanced nature in the clinically involved cases of leprosy (L series). Two BL types of cases from the L series, showed presence of M. leprae in Schwann cell cytoplasm of myelinated and unmyelinated fibers, perineurial cells, in endothelial cells and macrophages. In cases having impaired sensory modalities (L series), thickening of the perineurium was due to increase in the number of layers of perineurial cells in addition to the increase in collagen. Probably one of the ways in which unmyelinated fibers degenerate is by splitting the Schwann cell columns and extrusion of the axons. Collagen pockets were seen in the LN series of cases. These are probably the degenerated nonmyelinated fibers being replaced by collagen fibrils. Postoperative clinical charting was done on the patient whose IRC nerves were removed. It showed complete restoration of all modalities of sensation in the area of its distribution by the end of three months.

Clinical, electrophysiological, quantitative, histologic and ultrastructural studies of the index branch of the radial cutaneous nerve in leprosy. I. Preliminary report.

The index branch of the radial cutaneous nerve has been demonstrated as a constant nerve which can readily biopsied under local anesthesia and yields a nerve which is of suitable size for quantitative and qualitative studies both by light and electron microscopy. It supplies a limited but constant area where the sensory loss does not disturb the patient. Definite ultrastructural changes have been demonstrated in the clinically normal nerves of leprosy patients. These nerves have also revealed a loss in the small myelinated and unmyelinated fibers, which correlated with the common clinical findings of the absence of sweating and dissociated sensory loss in this disease. Gross damage has been encountered in nerves which showed only early signs of clinical damage even with refined methods of sensory testing. These nerves would have passed as normal on routine testing by No. 5 nylon. Regeneration of small fibers was noted following loss of large size fibers. Nerve conduction velocity may be a useful tool in early diagnosis.