Polyneuritic leprosy presenting with bone changes prior to the onset of florid skin manifestation

Introduction

Pure neuritic leprosy is an entity recognised by the Indian leprologists.[1] On the other hand, leprologists elsewhere do not give much credence to such a view as in their view involvement of the nerve, without major manifestations on the skin is not a feasibility.[2],[3] However, is Southern India it is a common entity and the present case is reported to illustrate the diverse modes of presentations of poly-neuritic leprosy.

Case Report

A 32- year- old man presented with com-plaint of swelling of right foot of 5 months duatation. The condition followed injury to the right foot, after which he noticed difficulty to walk and weakness of right foot. Patient was a chronic alcoholic, since 5 years. Local examination showed a swelling on the dorsal aspect of right foot 10 cm X 10 cm in size, extending from the ankle joint to 2 cm behind the proximal end of toes. The swelling was tender, not movable, there was no rise of temperature and bor-ders were irregular. There were ill-defined hypopig-mented le-sions on the right leg. Hair was lost in some places and skin was shiny. Ther-mal, tactile and pain sensations were im-paired on right leg. Lateral popliteal and posterior tibia) nerves were thickened and tender. Routine in-vestigations were within normal limits. Slit - skin smear was negative for AFB. Blood VDRL was non reactive. X-ray of the right foot showed areas of os-teoporosis with an area of new bone formation [Figure - 1]. Histopathology of skin showed infiltration of mononuclear cells around the nerves and skin ap-pendages with thickening of perineurium.

Discussion

It is an established fact that leprosy is the disease of nerves. It is also established that Schwann cells of the nerves are the first targets of M.leprae. Consequently it must be presumed that neural mani-festations are ought to be the earliest manifesta-tions of M. leprae infection. These manifestations can be subjective or objective. In the earliest stage itself i.e., indeterminate stage, it can manifest as inco-or-dination, pain, trivial deformities, loss of hair in the distribution of the nerve, anhidrosis, hypopigmentation, dryness or ichthyosis, paresthe-sia and nail abnormalities. Later manifestations like bullous lesions at acral parts can occur due to de-creased threshold to pain. Hyperkeratosis and fis-suring of palms and soles occur as a defence reac-tion subsequently.

Further, it must be understood, that early neuritic stage is the preliminary stage of leprosy. It may continue as such in nerves or progress or dis-seminate based on immunity.

During the initial indeterminate stage in nerves, other structures like bones, cartilages, muscles, ligaments, tendons and vassels can be af-fected. This can occur directly by invasion by organ-ism and indirectly through involvement of nerves with consequent osteoporosis and delayed healing, In the case presently reported, this phenomen has happened.

As per the classification of leprosy by westerners,[2],[3] the polyneuritic leprosy is mostly a cutaneous form unrecognised or the disease which had been incompletely treated. However Indian leprologists,[1] recognise a clean neuritic or polyneu-ritic type. Lack of proper assessment of the modali-ties of presentation seems to be the main cause of non-recognition of neuritic type of leprosy. In the case herein reported there were changes in bones prior to the onset of polar form of leprosy on skin.