Pocket Medicine: The Massachusetts General Hospital Handbook of Internal Medicine (90 page)

• Monthly clinical evaluation to monitor for Rx response and adverse drug rxns • “Paradoxical
worsening
” of sx can occur after starting Rx. More common w/ extrapulm. TB (eg, tuberculoma, LAN) likely due to hypersensitivity response to killing of bacilli. More frequent/severe w/ concurrent immune reconstitution (eg, HIV
Pts started on ARVs, Pts taken off immunosuppress, etc.).
Must r/o tx failure
(repeat Cx, imaging, etc.).

HIV/AIDS

Definition

• AIDS: HIV + CD4 <200/mm
³
or
AIDS-defining opportunistic infection (OI)
or
malignancy
Epidemiology

•
1 million Americans living w/ HIV;
34 million individuals worldwide • 20% in U.S. are unaware of infection; 6th leading cause of death in 25–44-y age group • Routes: sexual (risk is 0.3% for male-to-male, 0.2% for male-to-female, 0.1% for female-to-male transmission), IVDU, transfusions, needle sticks (0.3%), vertical (15–40% w/o ARV) • Postexposure (risk infxn ~0.3%) Ppx: 2 NRTIs (+ PI or NNRTI if high-risk) × 4 wk
Acute retroviral syndrome (ARS)

• Occurs in ~40–90% of Pts ~2–6 wk after infxn; ± ELISA,
viral load (2 wk after infxn); early ART in ARS may be beneficial (
NEJM
2013;368:207 & 218) • Mono-like syndrome (↑ mucocut. & neuro manifestations compared to EBV or CMV)
Diagnostic studies

•
ELISA
for HIV-1 Ab/Ag:
1–12 wk after acute infxn; >99% Se; 1° screening test •
Western blot
:
if ≥2 bands from HIV genome; >99% Sp; confirmatory after
ELISA •
Rapid preliminary tests
: 4 Ab tests; use saliva, plasma, blood or serum; 99% Se & 96–99% Sp (
Annals
2008;149:153); PPV in low prev populations as low as 50%

•
PCR (viral load)
: detects HIV-1 RNA in plasma; assay range is 48–10 million copies/mL ~2% false
, but usually low # copies; in contrast, should be very high (>750 k) in 1° infxn •
At least 1 time HIV screening recommended for all adult Pts
(
MMWR
2006;55:1) •
CD4 count
: not a dx test, b/c can be HIV
w/ normal CD4 or be HIV
w/ low CD4

Approach to newly diagnosed HIV
Pt

•
Document HIV infection
; counseling re: treatment options, adherence & disclosure •
H&P
(including focus on h/o OIs, STDs);
review all current meds
•
Lab evaluation
: CD4 count, PCR, HIV genotype, CBC w/ diff., Cr, lytes, LFTs, A1c & fasting lipids; PPD or IGRA, syphilis & toxo screen & CMV IgG; HAV, HBV, & HCV serologies;
Chlamydia
& gonorrhea screen; baseline CXR; Pap smear/anal pap in
/