Authors:
R. Vadapalli1, M. A.K1, M. Yerasu1, A. S. Vadapalli2, N. Chidambaranathan3; 1Hyderabad/IN, 2Pune AFMC/IN, 3Chennai/IN
DOI:
10.1594/essr2017/P-0180
Background
Nerve involvement. Leprosy often has an insidious protracted course and may not be recognized early.
In leprosy,
all physiological functions (sensory,
motor,
and autonomic) of a peripheral nerve are likely to be affected.
Sensory functions are most severely affected.
tuberculoid leprosy,
involvement of small dermal nerves of cooler parts of the body produces patchy areas of sensory loss.
Pain,
temperature,
touch,
and pressure sensations are typically impaired in affected skin areas.
Vibration and proprioceptive sensations are spared until later,
when nerve trunks are affected.
In lepromatous leprosy there is widespread symmetrical sensory loss,
particularly in cooler parts of the body.
Early in the lepromatous disease,
the loss of sensation is limited to knee,
dorsum of the hand,
forearm,
and lateral legs due to infiltration of small dermal nerves.
Patients with advanced lepromatous leprosy may also have progressive symmetrical,
distal peripheral neuropathy; damage to nerve trunks may superimpose a picture like mononeuritis multiplex (Sabin 1969; Sabin et al 1993; Nations et al 1998; Ooi and Srinivasan 2004; Polston et al 2004).
Borderline leprosy has a high propensity to involve nerve trunks,
producing a picture of multiple mononeuropathies or mononeuritis multiplex.
The most frequently affected peripheral nerves are peroneal and posterior tibial nerves in the lower extremities and ulnar nerve in the upper extremities.
Patients with borderline leprosy have an unstable immune balance between the host's cell-mediated immunity and bacterial replication and can progress unpredictably to either pole (Boggild et al 2004).