Infectious disease

Question 1

What is immune reconstitution inflammatory syndrome (IRIS)?

Answer 1

Patients with HIV initiated on antiretroviral therapy experience a potent immune recovery. Within weeks, viral load often becomes undetectable and CD4 counts rise dramatically. The renewed ability to recognize and respond to foreign antigens can result in an overabundant inflammatory response to an ongoing infection, which causes a paradoxical worsening of infectious symptoms. IRIS usually occurs several weeks after antiviral initiation and is most common in those who had low CD4 counts and high viral loads.

Question 2

What fluids/secretions/excretions are considered non-infectious if no blood is seen in them in HIV-infected patients?

Answer 2

Urine, feces, tears, and vomitus

Question 3

What is ecthyma gangrenosum?

Answer 3

Cause by Pseudomonas aeruginosa bacteremia in immunocompromised patients. Bacteria invade the perivascular structures (media, adventitia) of veins or arteries and induce secondary ischemic necrosis of the overlying tissue. This manifests with painless, red macules that rapidly progress to pustules/bullae and then quickly evolve into gangrenous ulcers with raised violaceous margins. The anogenital area, axilla, and extremities are most commonly affected, and single or multiple lesions may occur. Fever and signs of systemic illness are typically present.