Other (non-TB) Mycobacteria Flashcards
Which two species of mycobacteria cause leprosy?
M. Leprae and M. Lepromatosis
How long is the incubation period for leprosy?
2-10 years
How contagious is leprosy?
Not very contagious. Requires contact with nasal secretions (respiratory droplet transmission). Only really spreads among those living in poverty.
What is the treatment for leprosy?
Rifampicin
Dapsone
Clofazimine (if multibacillary)
What is another name for leprosy?
Hansen’s disease
What are the key dermatological manifestations of leprosy?
Depigmentation Macules Plaques Nodules Trophic ulcers
What are the key neurological manifestations of leprosy?
Thickened nerves
Sensory neuropathy
Most disability in leprosy is secondary to nerve damage.
What are the key ophthalmic complications of leprosy?
Keratitis
Iridocyclitis
What is the key orthopaedic complication of leprosy?
Periositis aseptic necrosis
Describe the immunological/clinical spectrum of leprosy.
The spectrum has 5 levels, correlating with the level of cell-mediated immunity.
Tuberculoid (TT): high cell-mediated immunity therefore restricted growth of pathogen. Paucibacillary. Th-1 mediated. Depigmented lesions.
Borderline tuberculoid (BT): nerve damage
Borderline (BB): multiple plaques
Borderline lepromatous (BL)
Lepromatous (LL): cell-mediated immunity very ineffective so widespread dissemination of the bacilli. Multibacillary. Th2-mediated. Neuropathic ulcers
Which mycobacteria cause intracellulare infection?
M. avium and M. intracellulare (=M. avium intracellulare complex/MAIC)
Name 3 mycobacteria with no person-person transmission
M. avium complex
M. marinarum
M. ulcerans
- associated with environmental transmission eg from other species
How well do the non-TB, non-leprosy mycobacteria respond to standard anti-TB treatment?
Not very well, usually poor response
How does M. Avium present in children?
Pharyngitis and cervical adenitits
How can M. Avium present in immunocompromised patients?
Osteomyelitis
Describe the pulmonary aspects of MAIC infection.
Looks like TB. Usually single lobe involvement
How does MAIC present in elderly patients?
Chronic pulmonary infection
How does MAIC present in HIV/AIDS patients?
Disseminated multibacillary infection
Mycobacteraemia
Long standing diarrhoea
Which mycobacterium causes fish tank granuloma?
M. marinarum
Describe the dermatological presentation of fish tank granuloma
Single or clusters of papules/plaques
Which key phrases hint at fish tank granuloma?
Patient has some association with swimming pools/aquariums
Which mycobacterium causes Buruli ulcers?
M. Ulcerans
How is M. Ulcerans transmitted?
Insect bites, particularly in Australia and the tropics
Descibe the progress of a Buruli ulcer
Begins as a painless nodule, slowly progresses to ulceration, scarring and contractures. Can cause hideous deformity but seldom fatal.
