0071643192.pdf

INFECTIOUS DISEASE

A 25-year-old male with known HIV/AIDS (last CD4 count <200) presents

with hypoxia, a chronic cough, and a CXR showing diffuse interstitial infil-

trates. In addition to normal bacterial pneumonia treatment, what other

organism should be emergently covered and what test needs to be done before

initiating treatment?

Pneumocystis cariniipneumonia (PCP) and an ABG to determine the need

for prednisone.

HIV/AIDS

■ RNA retrovirus

■ Risk factors

■ Male with male sex

■ IVDA

■ Unprotected intercourse

■ Blood transfusion prior to 1985

■ Maternal transmission

DIAGNOSIS

■ Sequential enzyme-linked immunoassay (EIA) and Western blot (~99%

sensitive/specific)

■ Positive 3–12 weeks after exposure

■ Confirm with two tests.

■ Rapid HIV test may substitute for EIA.

■ Time course. See Table 8.2.

TABLE 8.2. HIV Time Course

STAGE CD4 COUNT TIMECOURSE CLINICAL

Exposure Normal N/A Via blood/blood products, semen, vaginal secretions,

breast milk, or transplacentally

Acute HIV syndrome Normal 2—4 wk after exposure Flulike illness for 1—3 wk

Seroconversion Normal 3—12 wk after exposure Lab tests become positive.

Asymptomatic > 500 Mean: Asymptomatic, generalized lymphadenopathy

(incubation) period Adults =8 yr

Children=2 yr

Early symptomatic 200—500 Variable Thrush, pneumonia, herpes zoster, hairy leukoplakia,

B-cell lymphoma, Hodgkin disease, ITP, Kaposi

sarcoma (KS), tuberculosis (TB)

Late symptomatic < 200 Variable Esophageal candidiasis, cytomegalovirus (CMV)

(AIDS) retinitis, PCP, HIV encephalopathy, disseminated

histoplasmosis,Salmonellasepticemia

End-stage AIDS < 50 Variable Disseminated CMV, Mycoplasma avium