Early nerve damage in leprosy: an electrophysiological study of ulnar and median nerves in patients with and without clinical neural deficits.

BACKGROUND: Peripheral nerve trunk involvement in leprosy is very common. However, by the time it becomes clinically manifest, the damage is quite advanced. If the preclinical nerve damage can be detected early, the deformities and disabilities can be prevented to a large extent. AIMS: To assess the electrophysiological functions of the ulnar and median nerve trunks in cases of clinically manifest leprosy with and without manifest nerve damage at different durations of nerve damage. MATERIALS AND METHODS: Electrophysiological functions of ulnar and median nerves were studied in leprosy patients, both normal and at different stages of disease and damage. PB cases, having disease for six months or less, without neurological symptoms and clinically normal appearing nerve. STATISTICAL METHODS: Mean was taken of different values. The changes in values of different parameters were expressed as percentage change with reference to the control values (increase or decrease). RESULTS: Reduced nerve conduction velocities and changes in latency and amplitude were observed. Changes in sensory nerve conduction were more pronounced. Sensory latencies and amplitude changes were more severe than motor latencies and amplitudes in cases with manifest muscle palsies. Changes in MB cases were less marked. CONCLUSIONS: Further studies are needed to identify parameters likely to be helpful in the diagnosis of early nerve damage.

Facial onset sensory and motor neuronopathy (FOSMN syndrome): a novel syndrome in neurology.

A 'syringomyelia-like' syndrome has been infrequently reported in neurological disorders such as Tangiers disease and lepromatous leprosy. This study reports a novel 'syringomyelia-like' syndrome in four adult male patients, which we have termed facial onset sensory and motor neuronopathy, or FOSMN syndrome, that appears to have a neurodegenerative aetiology. Clinical, neurophysiological and pathological data of four patients were reviewed, including the autopsy in one patient. Four male patients (mean age at onset 43), initially developed paraesthesiae and numbness in a trigeminal nerve distribution, which slowly progressed to involve the scalp, neck, upper trunk and upper limbs in sequential order. Motor manifestations, including cramps, fasciculations, dysphagia, dysarthria, muscle weakness and atrophy developed later in the course of the illness. Neurophysiological findings revealed a generalized sensory motor neuronopathy of caudally decreasing severity in all four patients. Autopsy in one patient disclosed loss of motoneurons in the hypoglossal nucleus and cervical anterior horns, along with loss of sensory neurons in the main trigeminal sensory nucleus and dorsal root ganglia. FOSMN syndrome appears to be a slowly progressive neurodegenerative disorder, whose pathogenesis remains to be determined.

The INFIR Cohort Study: assessment of sensory and motor neuropathy in leprosy at baseline.

AIM: To compare different method(s) to detect peripheral neuropathy in leprosy and to study the validity of the monofilament test (MF) and the voluntary muscle test (VMT) as standard tests of nerve function. DESIGN: A multi-centre cohort study of 303 multibacillary (MB) leprosy patients. METHODS: Newly registered MB patients requiring a full course of MDT were recruited in two leprosy outpatient clinics in North India. Controls were people without leprosy or neurological conditions, attending the dermatological outpatient departments of the same clinics. Nerve function was evaluated electrophysiologically using standard parameters for sensory and motor nerve conduction (NC) testing, warm and cold detection thresholds (W/CDT), vibration perception thresholds, dynamometry, MF and VMT. The latter two defined the outcomes of sensory and motor impairment. RESULTS: 115 patients had nerve damage or a reaction of recent onset at diagnosis. Sensory and motor amplitudes and WDTs were the most frequently abnormal. Among the nerves tested, the sural and posterior tibial were the most frequently impaired. In the ulnar nerve, sensory latencies were abnormal in 25% of subjects; amplitudes in 40%. Ulnar above-elbow motor conduction velocities were abnormal in 39% and amplitudes 32%. WDTs were much more frequently affected than CDTs in all nerves tested. The thresholds of all test parameters differed significantly between controls and patients, while only some differed between patients with and without reaction. Good concordance was observed between MF results and sensory latencies and velocities (direct concordance 80% for the ulnar). However, a proportion of nerves with abnormal MF results tested normal on one or more of the other tests or vice versa. Concordance between VMT and motor conduction velocities was good for the ulnar nerve, but for the median and peroneal nerves, the proportion impaired by VMT out of those with abnormal motor conduction was very low. CONCLUSIONS: Concordance between monofilaments and other sensory function test results was good, supporting the validity of the monofilaments as standard screening test of sensory function. Concordance between VMT results and motor nerve conduction was good for the ulnar nerve, but very few median and peroneal nerves with abnormal conduction had an abnormal VMT. A more sensitive manual motor test may be needed for these nerves. Of the nerve assessment tests conducted, NC amplitudes and warm sensation were the most frequently affected. Therefore, nerve conduction studies and WDT measurements appear to be most promising tests for early detection of leprous neuropathy. The pattern of concordance between tactile and thermal sensory impairment failed to support the hypothesis that small fibre neuropathy always precedes large fibre damage. Warm sensation was more frequently affected than cold sensation. This could indicate that unmyelinated C fibres are more frequently affected than small myelinated Asigma fibres.

Enhancement in the histological diagnosis of leprosy in patients with only sensory loss by demonstration of mycobacterial antigens using anti-BCG polyclonal antibodies.

This study was undertaken to assess whether the immunoperoxidase technique using anti-BCG serum is able to confirm the diagnosis of early leprosy among patients whose unique clinical manifestation is a localized area of sensory loss, in a higher proportion than the routine mycobacterial staining methods, namely hematoxylin-eosin and Wade. The study was held in the north of a hyper-endemic area of leprosy, Manaus, Amazonas (Brazil). Fifty-one paraffin-embedded skin biopsy blocks were retrieved and processed for the immunohistochemical study, by means of anti-BCG polyclonal antibodies for the detection of mycobacterial antigens. The routine stains confirmed the leprosy diagnosis in 17% of the cases, while the immunostaining method confirmed it in 47%. The McNemar test showed that the observed difference between these two techniques was statistically significant (p = < 0.05). In the same way, 50 blocks of skin conditions considered in the differential histopathological diagnosis of early leprosy were processed for the immunohistochemical test to analyze the possibility of false-positive results which occurred in 8 (16%) patients. The study suggests that immunostaining may increase the proportion of the routine histological diagnosis of leprosy in patients who have sensory loss only, even while using biopsies obtained in fieldwork conditions. This is very advantageous in hyper-endemic areas and in areas that are in the post-elimination period of leprosy control where sensory loss may be a sentinel sign of the disease.

[Should biopsy be done on the sensory branch of the radial nerve in leprosy patients? Apropos of 112 cases]. / Doit-on pratiquer des biopsies de la branche sensitive du nerf radial chez les malades lépreux? A propos de 112 cas.

Biopsies of the superficial sensory branch of the radial nerve are contested. Some authors mention it to be simple and without harm, but others are formally against this procedure. At ILAD, 274 biopsies were made between 1986 to 1992. We present a review of 112 leprosy patients for whom biopsy was done. On 112 reexamined patients, we observed 2 benign neuroma, hence 2%. The comparison of nerve function before biopsy and after, of 63 of the 112 patients, reexamination shows no significant modification of the functional score. Given even the occurrence of benign neuroma in only 2% of the cases, the authors do not recommend the biopsy of the superficial sensory branch of the radial nerve. For research purposes on neuritis in leprosy, as well as to assure diagnosis in primary neuritic leprosy, we propose the biopsy of the sensory branch of the musculo cutaneous nerve at elbow level.

[Peripheral nerve lesions of experimental leprosy in monkeys. V. Histopathological finding of cutaneous nerves and cutaneous sensory organs].

The skin samples of each palm side and dorsum side of finger, nose and peripheral nerves running under the finger skin at the area between proximal phalanx and distal phalanx of mangabey monkey A022 and rhesus monkey A125 were studied by histopathological methods (semithin section and light microscopic findings). Results found about this study were as follows. 1. In spite of the existence of a large amount of leprosy bacilli at the areas of corium and subcutis, some of Meissner's corpuscles, Vater-Pacinian corpuscles (or Golgi-Mazzoni's corpuscles) and Krauze's end bulbs-like structures were observed. 2. Occasionally, several intracytoplasmic foamy structures containing a large amount of leprosy bacilli were observed at the shallow and deep layers of stratum papillare of corium, where leprosy bacilli were not so remarkable as shown on Figure 4. So, it was thought that the affinity of leprosy bacilli to free nerve endings should be exist there. 3. Some of M. arrector pili were kept in good condition in spite of the existence of multiplying leprosy bacilli around the hair follicles. 4. It was thought that the histopathological findings of the fascicles of cutaneous nerves were classified to 4 patterns. The first pattern of histopathological finding of the cutaneous nerve was shown as A on Figure 25. In this pattern observed in almost of all the fascicles locating at the subcutis, no leprosy bacillus was observed inside the fascicles, and the nerve fibers were kept in good condition. The second pattern observed in almost of all the fascicles located at the corium, was shown as B on Figure 25. In this pattern, a large amount of leprosy bacilli were observed inside the fascicles, and the nerve fibers were often kept in good condition. The third pattern observed in almost of all the fascicles located at the deep layer of corium and subcutis, was shown as C on Figure 25. In this pattern, not only multiplying leprosy bacilli but also remarkable fibrosis were found inside one fascicle, and many nerve fibers disappeared by the existence of the bacilli and fibrosis. The final pattern observed in almost of all the fascicles located at the deep layer of corium and subcutis, was shown as D on Figure 25. In this pattern, remarkable fibrosis was observed inside the fascicles, and the nerve fibers often disappeared by the existence of fibrosis.(ABSTRACT TRUNCATED AT 400 WORDS)