Contents
Leprosy is a chronic granulomatous disease.
Organism
- mycobacterium leprae = intracellular parasite.
- Incubation period
- tuberculoid = 2-5 years
- lepromatous = 8-11 years
Transmission
- Spread in nasal discharges to the skin or nose.
- Infectivity is low (<10% those exposed show any signs of infection)
Epidemiology
Geographical distribution of disease is patchy with 70% cases in India
Pathogenesis
Bacilli enter through the respiratory tract (usually) and multiply in peripheral Schwann cells (limbs and face)
- Form of disease determined by level of cell mediated immunity:
- High levels- tuberculoid disease
- No/few skin/nerve lesions appear followed by spont. healing.
- Absent-lepromatous diease
- Other tissues also become involved (eyes, testes, kidneys, smooth
- Muscle, reticuloendothelia system and vascular endothelium.
Clinical features
- Skin lesions
- Parasthesia
- Thickenned peripheral nerves.
Complications
- Often thought to cause loss of limbs (“skin falling off”) but in recent times this is less of an issue.
- Loss of sensation produces loss of protective reactions àresulting in injuryàinfection can develop and in the past (when not caught early) could result in the need for amputation.
Diagnosis
*Early diagnosis is essential in preventing disability*
- Clinical findings of one or more cardinal signs.
- Biopsy of skin lesion or nerve.
- AFBs on slit skin smears
Treatment
Multi-drug regimen
- Rifampicin
- Dapsone
- Clofazimine
References
- Murtagh’s General Practice. 6th Ed. (2015) John Murtagh, Jill Rosenblatt
- Oxford Handbook of General Practice. 3rd Ed. (2010) Simon, C., Everitt, H., van Drop, F.
- Beers, MH., Porter RS., Jones, TV., Kaplan JL., Berkwits, M. The Merck Manual of Diagnosis and Therapy