A 14-year-old boy is brought to the emergency department by his parents due to cough and difficulty breathing. The patient has had a nonproductive cough for a week that worsens at night and prevents him from sleeping well. This morning he has been short of breath while walking and speaking. The boy has also had fever for the past 2 days. Medical history is notable for end-stage renal disease due to obstructive uropathy from a congenital posterior urethral valve. He received a living related donor kidney transplant 3 months ago. Temperature is 38.2 C (100.8 F), blood pressure is 120/80 mm Hg, pulse is 98/min, and respirations are 31/min; pulse oximetry is 82% on room air. Physical examination shows a tired-appearing boy in mild respiratory distress seated on a chair. He is tachypneic with diffuse rales throughout the lungs. His donor kidney is palpable in the lower abdomen and is nontender. Laboratory studies show a creatinine of 0.6 mg/dL. When questioned alone, the patient says that he has not been taking all his medications as prescribed. Which of the following would most likely have prevented this patient's current illness?

Question

A 14-year-old boy is brought to the emergency department by his parents due to cough and difficulty breathing.  The patient has had a nonproductive cough for a week that worsens at night and prevents him from sleeping well.  This morning he has been short of breath while walking and speaking.  The boy has also had fever for the past 2 days.  Medical history is notable for end-stage renal disease due to obstructive uropathy from a congenital posterior urethral valve.  He received a living related donor kidney transplant 3 months ago.  Temperature is 38.2 C (100.8 F), blood pressure is 120/80 mm Hg, pulse is 98/min, and respirations are 31/min; pulse oximetry is 82% on room air.  Physical examination shows a tired-appearing boy in mild respiratory distress seated on a chair.  He is tachypneic with diffuse rales throughout the lungs.  His donor kidney is palpable in the lower abdomen and is nontender.  Laboratory studies show a creatinine of 0.6 mg/dL.  When questioned alone, the patient says that he has not been taking all his medications as prescribed.  Which of the following would most likely have prevented this patient's current illness?

Quizplus · Accepted Answer

Explanation: 11ec2b69_bfb9_384a_8f63_a31d739f0c50_MD0005_00 This patient has the classic history and physical examination findings of Pneumocystis jiroveci pneumonia (PCP). PCP is seen in patients with defects in cell-mediated immunity. It is most commonly seen in HIV-infected patients with CD4 cell counts <200 cells/mm³, but can also be seen in those receiving immune modulation following transplantation, as in this patient. PCP has an insidious onset and usually presents with low-grade fever, nonproductive cough, dyspnea, and tachypnea. Hypoxia is prominent and may be out of proportion to relatively mild findings on chest auscultation. Chest x-rays reveal diffuse, bilateral ground-glass opacities. Trimethoprim-sulfamethoxazole is the treatment of choice for suspected or proven PCP. Intravenous therapy should be used initially, with oral therapy initiated once the patient has signs of clinical recovery. Trimethoprim-sulfamethoxazole is highly effective when used prophylactically to prevent PCP in at-risk patients, and failure to adhere to trimethoprim-sulfamethoxazole prophylaxis is the most likely cause of this patient's disease. (Choice A) Fluconazole prophylaxis is commonly used for patients with cell-mediated immune defects to prevent esophageal or cutaneous candidiasis. Candida is an extremely rare cause of pneumonia. (Choice B) Influenza generally presents acutely with high fever, cough, myalgias, and pharyngitis in contrast to the more gradual onset of PCP. Although vaccination with inactivated intramuscular vaccine is recommended for all patients, it would not have prevented this patient's infection. (Choice C) Prednisone may be used for immunosuppression after transplantation, and it is sometimes used as adjunctive therapy for severe Pneumocystis pneumonia to improve air exchange. Despite its use for PCP treatment, prednisone has no role in PCP prevention. (Choice E) Antiretroviral therapy such as zidovudine plays an important role in preventing CD4 cell depletion and therefore risk of PCP in HIV-infected patients. However, zidovudine is not used for HIV-negative organ recipients. Educational objective: Pneumocystis jiroveci pneumonia (PCP) can cause life-threatening respiratory infection in immunocompromised patients, such as those with advanced HIV infection or who are on chronic immunosuppression. Prophylaxis, typically with trimethoprim-sulfamethoxazole, is indicated for at-risk patients. References: Prophylaxis for pneumocystis pneumonia (PCP) in non-HIV immunocompromised patients. (http://www.ncbi.nlm.nih.gov/pubmed/25269391)

A 14-Year-Old Boy Is Brought to the Emergency Department by His