Management of nerve abscess in leprosy. There is no one rule for every occasion.

Leprosy Mailing List, September 2nd, 2008

Ref.: Management of nerve abscess in leprosy. There is no one rule for every occasion.
From: Warren G., Sydney, Australia


Dear Salvatore,

Interested in the comments about nerve abscesses. In leprosy it is essential that we separate the abscess due to the destruction of the nerve from the antibody-antigen- immunity reaction to that which is caused by a secondary bacillary infection. Sure in the latter it may be essential that the abscess be drained and those bacillary abscesses are usually easy to recognize by the heat and swelling in association with the infection. If they are not drained they may well cause other problems as mentioned by Dr Salafia in a letter from Mumbai (in LML) on August 27th.

However, even when the damaged nerve is infected by foreign bacteria it may eventually resolve, spontaneously, without surgery, leaving only a small lump behind and no problems other than the neural deficits that are the direct result of the destroyed nerve fibres. Surgery will not produce recovery in fact there may be an increase in the neural deficit due to the surgeons knife.

However when the active inflammation of the nerve results is caseation of the nerve fibres and there is no complicating secondary infection this is a totally different matter. It may be possible to palpate the swelling on the nerve but it will usually be painless and no obvious heat. There may be motor and obvious sensory abnormality depending on where the nerve is and that neural deficit may have only recently developed.

One frequently sees these small abscesses on the backs of the hands and then it is usually NOT necessary to try and excise them. They cause no disability and are not really unsightly (especially when compared with all the other problems the patient may have). One often finds them at first diagnosis and once the patient starts on MDT there are not likely to be any or certainly not many more develop and the ones that do develop will slowly absorb and disappear. There is no advantage in excising because the nerve fibres destroyed in the development of the abscess will not and cannot recover. Once treatment starts the number of bacilli will rapidly reduce and further increase in the number of abscesses is unlikely after the first few weeks of MDT.

Surgery may well result in damage to nerve fibres that were not initially involved so may make the neural deficit worse. Best advice is chart size and signs of neural deficit regularly every week for first few weeks and then monthly. If the abscess is still increasing after 4-6 months then obviously it is more than just the effects of an acute upgrading reaction producing caseation. And surgical intervention may need to be considered.

In reference to Dr Srinivasan’s letter (LML Aug. 31st, 2008) I would say that an intraneural abscess usually does not need to be opened unless it is very large and causing pressure problems on tissues around the nerve. The damage to the nerve has been done. Rest Protect the limb give full MDT (steroids are Not indicated usually) give antibiotics if suspect infection and watch carefully.

One patient was sent to me for drainage. I wondered if he really had leprosy but he had a very swollen ulnar nerve exactly in the right place; so we explored it to find it a sarcoid! Another had a very red swollen area over the elbow and extending up into the arm that had been there for several years he said, in spite of MDT. On opening we drained 3-400cc of frank pus the grew an interesting collection of bacteria!

In leprosy I have learnt never to say that something never happens. The most unusual things can happen especially if we do not look for problems and if we try to stick to routines like “Open every abscess!”. There is no one rule for every occasion. I hope these thoughts will help some to save nerve function.

Best regards,

Grace Warren