Acute respiratory failure following HAART introduction in patients treatedfor Pneumocystis carinii pneumonia

Cases of paradoxical worsening of opportunistic infections shortly after th e beginning of highly active antiretroviral therapy (HAART) prompted questi ons on the optimal timing of introduction of HAART in patients with inaugur al AIDS-related opportunistic infections. We describe three cases of acute respiratory failure after early introduction of HAART in patients treated f or Pneumocystis carinii pneumonia (PCP). The three patients had severe PCP that initially improved with anti-PCP and adjunctive steroid therapy. HAART was introduced 1 to 16 d after diagnosis of PCP, and steroids were stopped on Day 15. Seven to 17 d after HAART introduction, the three patients deve loped a second episode of severe acute respiratory failure with high-grade fever and patchy alveolar opacities on the chest roentgenogram. PCP resista nt to cotrimoxazole, pulmonary superinfection, and drug-related pneumonitis were suspected but subsequently ruled out. Bronchoalveolar lavage and lung pathologic findings showed severe nonspecific pulmonary inflammatory foci surrounding a few persistent P. carinii cysts. All three patients recovered after HAART interruption or steroid reintroduction. We conclude that acute respiratory failure can recur after initiation of antiretroviral therapy i n patients being treated for severe PCP. This phenomenon could result from rapid pulmonary recruitment of fully competent immune and inflammatory cell s responding to a few persistent P. carinii cysts. A short course of steroi d therapy may suppress this reaction.