TUBERCULOSIS IN HIV Flashcards
What is the difference in lifetime chance of reactivation of latent TB between an individual who is HIV positive and another who is HIV negative?
HIV positive: 10% chance per annum
HIV negative: 10% chance over lifetime
How much more likely is a HIV positive individual to develop active TB than a HIV negative individual?
20-40 times more likely
What proportion of AIDS related deaths around the world are attributable to TB?
Around one quarter
What are the clinical features of TB?
Fever
Night sweats
Weight loss
Haemoptysis
How does HIV change the typical appearance of chest radiograph in someone with HIV?
Lacks characteristic upper zone cavitatory disease
Replaced by pulmonary infiltrates, mediastinal lymphadenopathy and pleural effusions
Are HIV positive patients with pulmonary TB more or less likely to be AFB sputum negative?
More likely which makes this inexpensive and rapid test less sensitive.
What does MODS stand for in the context of TB diagnostic tests?
Microscopic observation drug susceptibility assay
What does the microscopic observation drug susceptibility assay tell you about TB?
Information on drug resistance
How does HIV affect ease of diagnosis of TB?
Tends to make it harder and render tests less sensitive
Which TB diagnostic tests are rendered less sensitive by HIV?
Sputum smear for AFB
Sputum liquid culture
NAAT
Histology of granulomas - less AFB present
TST - tuberculin skin test
Rapid immune-based tests
Which TB diagnostic tests are unaffected by HIV?
MODS (Microscopic observation drug susceptibility assay)
Which TB diagnostic tests are rendered more sensitive by HIV?
Urine LAM (lipoarabinomannan)
What is the prevalence of drug resistant TB in HIV positive patients when compared with HIV negative patients?
2-3 times higher
This is not due to increased susceptibility to these strains, but more because HIV positive patients will rapidly develop active disease
What is the anti-TB drug that TB is most commonly resistant to?
Isoniazid
How does HIV affect anti-TB drug resistance?
Increases likelihood of rifampicin resistances