Pulmonary Infections in HIV patients: The big Offenders • Bacterial: Strep pneumo, H. flu, S. aureus, Pseudomonas aeruginosa, (nosocomial) Klebsiella and Enterbacter • Rhodococcus equi (upper lobe nodules, infiltrates, cavitation, looks like TB) • Nocardia • Viral: CMV, VZV, HSV • PCP • Malignancy: Lymphoma, Kaposi’s
Pulmonary Infections in HIV patients: History Taking • Typical patterns: acute illness with cough, fever, sputum, chest pain = bacterial pneumonia. Subacute onset with fevers, chills, sweats, weight loss = TB, pulmonary Kaposi’s. Insidious onset over days to weeks of dyspnea, fatigue, dry cough, low grade fevers = PCP. • Homosexual men have higher incidence of Kaposi’s. • IV drug users are at increased risk for bacterial pneumonia and MTB. • Exposures: TB (jail, homeless shelter, etc), Histo (Miss River Valley), Cocci (SW). • Child care: CMV. • Pets: crypto, toxo, pasteurella multocida.
Pulmonary Infections in HIV • Physical exam: lung exam (although may be clear), skin for Kaposi’s lesions, fundi (viral/fungal/MTB infections), lymph nodes • CD4 counts: bacterial pneumonia, MTB early on (CD4>500), PCP when CD4 <200, Toxo, CMV, MAC when CD4 count <100.
Imaging studies • CXR: typical PCP pattern is diffuse reticular or reticulonodular infiltrates in a perihilar or bibasilar distribution. However, up to 26% of pts with PCP pneumonia have normal CXR. • CT: can better define infiltrates (ex: Kaposi’s produces pattern of perivascular and peribronchial confluent opacities, whereas PCP is more diffuse). • CT is better at detecting early cystic changes (38% vs. 10% CXR).
Other noninvasive tests • Induced sputum: good for suspected bacterial pneumonia and TB. For PCP, varies widely. • Serology: Histo ( + serum 89%, urine 93% of pts with active pulm histo); crypto Ag (serum for disseminated disease). For PCP/CMV, not useful. • LDH: >200 93% sensitivity and 33% specificity; >450, sens 22% spec 100%. Their conclusions: very high LDH should make one suspect PCP or lymphoma. A normal LDH makes PCP less likely but does not rule it out. • ABG: may see wide A-a gradient.
Invasive Tests • Bronch: high yield and low complication rate make this the procedure of choice for pulmonary infections in HIV pts. • Slight decrease in sensitivity of BAL for breakthrough PCP. • Needle aspiration (esp of nodes, abscesses) • VATS with pleural disease
Treatment of PCP • Drugs of choice: TMP-SMX or Pentamidine. • Acutely ill: 15 mg of TMP comp per kg per day divided q 6-8h times 21 days • Mild-Mod: 2 tabs Bactrim DS po q8h x 21 d. • Alternative Agents: clindamycin-primaquine, dapsone-trimethoprim, atovaquone • Adjunctive corticosteroids: PaO2 less than 70 or A-a gradient >35. Prednisone 40 mg po bid x 5 days then 40 qd x 5 d then 20 mg qd x 11 d.