- Discussion:
- causative organism of leprosy is M. leprae;
- acid-fast, obligate, intracellular gram-positive bacillus that reproduces maximally at 27°C to 30°C;
- frequent subacute polyarthritis involving the small joints of the hands and feet;
- organism infects the skin and cutaneous nerves, its principal target being the Schwann-cell basal lamina;
- direct bacterial infection may lead to osteomyelitis or periostitis;
- dx: may require sural nerve biopsy;
- Fite's modification of the Ziehl–Neelsen acid-fast stain for mycobacteria may show bacilli in Schwann cells;
- hematoxylin and eosin stain: inflammatory infiltrate w/ plasma cells and lymphocytes and poorly formed aggregates of histiocytes;
- electron micrograph: loss of unmyelinated axons, manifested by the presence of so-called empty Schwann-cell stacks;
- ref: Value of nerve biopsy in the diagnosis and follow-up of leprosy: the role of vascular lesions and usefulness of nerve studies in the detection of persistent bacilli.
- Exam:
- doess not follow the anatomic distribution of the subcutaneous sensory nerves, of the mixed nerve trunks, of the sensory roots, or of the distal symmetrical sensory loss
- nerves are often involved in subcutaneous regions (bacteria thrive in cooler regions of the body);
- ulnar nerve is often involved at the elbow (treatment is submuscular transposition);
- median nerve may be involved at the wrist;
- hand involvement;
- painful dysesthesias
- sensory loss more pronounced on the dorsal than on the palmar surfaces;
- Treatment:
- dapsone and rifampin
Bone changes in leprosy: a correlation of clinical and radiographic features.
Clinical and laboratory studies of arthritis in leprosy.
Rheumatic manifestations of leprosy: clinical aspects.
Temperature-linked sensory loss. A unique pattern in leprosy.