From HATIP #3 - click here to read original article
MANAGING IMMUNE RECONSTITUTION DISEASE
In comments that arrived after the last issue was sent out, Dr Desmond Martin writes, from South Africa:
"Immune reconstitution disease (IRD, also known as Immune reconstitution inflammatory syndrome, IRIS) is a topic of its own. We are seeing more and more of this syndrome in our patients. In brief: "If one is able to delay ARV treatment this will lead to a reduction in the incidence of IRD. If however one is forced to commence ARV treatment early in the course of the TB treatment one must have a heightened awareness of the possibility of IRD and almost expect it to happen. It seems to be a lot more common in our setting compared to areas where TB is not endemic."
The key things to watch out for are fever, pulmonary infiltrates, abdominal pain, enlarging glands (both hilar or abdominal or elsewhere).
The typical scenario is a patient who commences ARVs in the face of significant immunosuppression (CD4+ < 50). It can occur in patients who were previously non-reactive on a Mantoux test. Remember in our setting the majority of the population are likely to be positive to a Mantoux at some stage of their lives and non-reactivity implies immunosuppression [rather than not having been exposed to TB].
"Steroids are often used as an adjunct to therapy; I however am ambivalent as to their use. One just has to sit tight on the situation and see it through. I have used steroids in certain circumstances (e.g. enlarging hilar node obstructing bronchus). When used the dose of cortisone would be something like 40-60 mg daily, typically for four to six weeks."
WHEN DOES A NEGATIVE TB SKIN TEST MEAN "NOT EXPOSED"?
A research letter published in the most recent issue of AIDS reports a US study which assessed the ability of 110 HIV positive patients to respond to several antigens, including PPD (TB proteins), in relation to their CD4 counts. When the CD4 count was below 50, as many as one third were anergic. When it rose between 50 and 100, the majority of those who had previously been anergic became reactive, and when it rose above 100, almost all were reactive. In this population, only 13 had been exposed to TB, but these included two individuals who had tested negative when their CD4 counts had been lower, before starting on ARV treatment. The implication is likely to be, that negative skin test results for TB can only be taken as truly negative when the CD4 count is above 100.
REFERENCE
Fisk TL et al. Detection of latent tuberculosis among HIV-infected patients after initiation of highly active antiretroviral therapy. AIDS 17:1102-1104, 2003.