Microbiology
Variable.
Epidemiologic Risks
As HIV patients take their HAART for the first time, they get a rebound in their CD4 counts and can become symptomatic for a variety of infections that were present, but asymptomatic due to the lack of an inflammatory response.
Non-HIV patients can get IRIS (PubMed)(PubMed): recovering neutropenics with hepatosplenic Candida (PubMed) and Aspergillus and postpartum (PubMed). In neutropenics with Aspergillus, IRIS is a good prognostic sign.
Can occur in any patient being weaned off steroids or biologics (PubMed).
IRIS can also occur in transplant patients with exacerbations due to fungi of all types, M. tuberculosis, cytomegalovirus, and polyomavirus nephropathy.
Ever see a study so detached from practice, yet interesting, as the one where they demonstrated those with a positive PET/CT prior to HAART were those who went on to develop IRIS. As if any insurance will authorize this $2000 exam for this indication.
Syndromes
Cytomegalovirus and Pneumocystis lead the list, but any of the standard HIV opportunistic infections can become symptomatic.
As part of IRIS, HIV patients can get a CD8 encephalitis (PubMed) that is treated with steroids.
Treatment
Per the infecting organism.
May use steroids for symptom relief depending in the infection/patient.
Notes
Bats with white-nose syndrome, due to Geomyces destructans, may also have IRIS. While hibernating they are immunosuppressed, get infected, and when they wake up get IRIS (PubMed) as their immune system reboots.
It can also manifest as a reaction to tattoo ink (PubMed).