Leprous Neuralgic Pain: Its Therapy and Pathogenesis

The invasion of M. leprae to the peripheral nervous system makes the main signs and symptoms of leprosy as the reflucts of many kind of reactions. In recent Japan, most doctors, working at leprosaria, can only see the arrested-disease patients with the manifestation of deformed appearances of face and extremities and with various neuralgias, instead of active typical signs. In this paper, the authors reported the effective treatment for neuralgias from which the patients have been suffering during their lives of leprosy, and also shortly discussed the pathogenesis of painful neuralgias associated with acute nerve swelling in the arrested-disease. The two thirds of about 200 cases of chronic neuralgias treated with long term administration of pen-oral methylcobalamine (methylated Vitamine B12) were well improved and could be broken away from anodynes. The Phantom limb pain-like neuralgias which is characterized by sudden and severe onset at the areas of arteficial legs of extremities or faces with complete sensory loss were well controlled by carbamazepine. 60 neuralgias in patients with lepromatous leprosy were associated with acute nerve swellings. Except 5 cases, tender and swollen nerves were found in clinically arrested stage, in other words, indifferent from clinical ENL. The careful examination could reveal the phenomenon especially at more proximal and deeper site of the nerve than those happened in usual ENL. They were treated with perineural injection method with methylcobalamin and glucocortico-steroid, resulting in complete healing of neuralgias and also in preventing the disturbances of nerve functions. Histopathological study of peripheral nerves derived from autopsied cases with arrested disease, revealed the findings as follows ; 1) M. leprae and their fragments, usually gathering around vessels, are never completely cleaned out by anti-leprosy drugs, 2) the relatively fresh nerve swellings seem to be the immunological reactions participated in the arterioles surrounded by edema, sometimes forming single fasciclar swelling and also forming Renaut's-like bodies in cases. From the definition of ENL, the possible mechanism of ENL occuring only in the nerve fascicle(s) in arrested disease patients without M. leprae for a long period in the dermal tissues, were discussed in accordance with the continuous anti-leprosy treatment, because 90% of the cases had been given drugs though more than 80% of them were arrested. If so, the inducer of ENL only