Infected trophic ulcers and tenderness of posterior tibial nerve in cured leprosy patients
To the Editor:
This is with reference to the letter by Dr. Anil H. Patki on the above subject in the September 1993 issue [Vol. 61 (3) pp. 473-474].
1. Very often patients with acutely inflamed plantar ulcers complain of pain (which can be quite severe) in the foot, and careful questioning reveals the site of pain as behind the tibial malleolus. The posterior tibial nerve shows exquisite tenderness in these cases. The inguinal lymph nodes are often, but not always, enlarged and tender. The nerve tenderness improves as the ulcer improves, rather slowly but steadily. Mild tenderness may persist for a while even after complete healing of the ulcer.
2. In my opinion this is not merely due to lymphangitis although that, perhaps, contributes to the clinical picture because: a) there is rarely, if ever, any associated inflammation of the superficial lymphatics in most of these cases, and b) the tenderness persists, although at a lower level, for some time even after control of the acute infection. It appears quite likely that there is a real neuritis of the posterior tibial nerve in these cases only it is not related to leprosy, as such, but to acute infection in the ulcer. The fact that the incidence of tetanus in leprosy patients with chronic plantar ulcers appears to be very much less than one would expect has been explained on the basis of intraneural and perineural fibrosis which would also block the lymphatics (1).
3. In the old dapsone monotherapy days, this clinical phenomenon was not very much stressed and, also, it did not matter. However, the situation today is different and, as Dr. Patki says, somebody examining such a patient (who has already been treated and discharged as cured) may easily diagnose disease activity/acute neuritis/reaction/relapse just because the posterior tibial nerve is very tender. I congratulate Dr. Patki for bringing this matter to our attention and I endorse his cautionary statement.
- H. Srinivasan, F.R.C.S. (Engl. & Edin.)
12/1 First Seaward Road
Valmiki Nagar
Madras-600 041, India
REFERENCES
1. SRINIVASAN, H. and DHARMENDRA. Neuropathic ulceration. In: Leprosy, Vol. I, Dharmendra, ed. Bombay: Kothari Medical Publishing House, 1978, p. 232.