A 54-year-old man comes to the office due to 2 weeks of progressive fever, exertional dyspnea, and nonproductive cough. The patient has a history of HIV infection but does not comply with antiretroviral therapy. Temperature is 38.9 C (102 F), blood pressure is 120/80 mm Hg, pulse is 100/min, and respirations are 28/min. Pulse oximetry is 80% on room air. Oxygen saturation increases to 92% with the use of a 100% nonrebreather mask. Laboratory results are as follows: CD4 count is 170/mm³ and lactate dehydrogenase level is 480 U/L. Chest x-ray reveals diffuse bilateral interstitial infiltrates. What is the most appropriate next step in management of this patient?

Question

Quizplus · Accepted Answer

Explanation: This patient with HIV has subacute dyspnea, fever, dry cough, elevated lactate dehydrogenase (LDH), and diffuse bilateral pulmonary infiltrates, raising strong suspicion for Pneumocystis pneumonia (PCP). Most cases arise in those with untreated AIDS who have CD4 counts <200/mm³. Manifestations are generally indolent and include exertional dyspnea, dry cough, and fever. Laboratory evaluation frequently reveals elevated LDH, and chest x-ray usually shows bilateral reticulonodular interstitial infiltrates. The diagnosis is confirmed when Pneumocystis jirovecii is identified in induced sputum or bronchoalveolar lavage. Treatment with trimethoprim-sulfamethoxazole (TMP-SMX) is generally curative. ³ Because P jirovecii proliferates within the alveoli and triggers a strong inflammatory response, patients with PCP often have significant hypoxia and a large alveolar-arterial oxygen gradient. Hypoxia often worsens with the initiation of antimicrobial treatment due to the release of pro-inflammatory intracellular macromolecules during lysis of the organism. Therefore, concomittant corticosteroids are generally administered to those with severe PCP to reduce the inflammatory response. Indications include: a PaO₂ ≤70 mm Hg an alveolar-arterial (A-a) gradient ≥35 mm Hg, or pulse oximetry <92% on room air. This patient's PaO₂ of 54 mm Hg on room air indicates a need for concomitant corticosteroids, not TMP-SMX alone (Choice E). ₂ Alternate oral regimens for mild/moderate PCP include dapsone-TMP, primaquine with clindamycin, or atovaquone suspension. Alternate regimens for moderate/severe disease include intravenous (IV) pentamidine or primaquine with IV clindamycin. Because pentamidine has high rates of adverse effects (eg, hypotension, hypoglycemia, nephrotoxicity, arrhythmias), it is generally reserved for patients with severe PCP who cannot tolerate TMP-SMX (Choice C). There is no evidence that this patient is unable to tolerate TMP-SMX. (Choice A) Patients with bacterial pneumonia usually have productive cough, lobar infiltrate on chest x-ray, and an elevated circulating bands. Community-acquired bacterial pneumonia is often treated with ceftriaxone, but concomitant azithromycin or doxycycline is usually added to cover atypical organisms. (Choice B) Antiretroviral therapy initiation is usually delayed 1-2 weeks in patients with PCP (until hypoxia is improved) due to the risk of worsened respiratory status from immune reconstitution syndrome. A transient delay in antiretroviral therapy also helps limit drug interactions and ensures that patients are tolerating PCP treatment. Educational objective: Manifestations of Pneumocystis pneumonia (PCP) in patients with HIV are usually indolent and include nonproductive cough, exertional dyspnea, fever, hypoxia, elevated lactate dehydrogenase, and bilateral interstitial infiltrates. Trimethoprim-sulfamethoxazole is the first-line treatment. Concomitant corticosteroids are administered for those with PaO₂ ≤70 mm Hg, alveolar-arterial gradient ≥35 mm Hg, or pulse oximetry <92% on room air to reduce risk of respiratory decompensation. ₂ References: Prevention and treatment of opportunistic infections in HIV-infected adults and adolescents: updated guidelines from the Centers for Disease Control and Prevention, National Institutes of Health, and HIV Medicine Association of the Infectious Diseases Society of America. (http://www.ncbi.nlm.nih.gov/pubmed/24585567)

A 54-Year-Old Man Comes to the Office Due to 2