A 45-year-old woman comes to the emergency department due to 3 days of fever, malaise, progressive dyspnea on exertion, dry cough, abdominal pain, and watery diarrhea. Her loose stools this morning were accompanied by bright red blood. The patient underwent allogeneic renal transplantation 6 months ago and is currently taking tacrolimus, mycophenolate, and prednisone. Two months ago, she developed severe leukopenia, which resolved after discontinuing trimethoprim-sulfamethoxazole and valganciclovir. She does not use tobacco, alcohol, or illicit drugs. Temperature is 38.9 C (102 F), blood pressure is 110/70 mm Hg, pulse is 114/min, and respirations are 22/min. Physical examination shows bilateral lung crackles and diffuse abdominal tenderness. Gross blood is seen on rectal examination. Laboratory results are as follows: Urinalysis is normal. Chest x-ray reveals bilateral interstitial infiltrates. Which of the following is the most likely cause of this patient's current condition?

Question

A 45-year-old woman comes to the emergency department due to 3 days of fever, malaise, progressive dyspnea on exertion, dry cough, abdominal pain, and watery diarrhea.  Her loose stools this morning were accompanied by bright red blood.  The patient underwent allogeneic renal transplantation 6 months ago and is currently taking tacrolimus, mycophenolate, and prednisone.  Two months ago, she developed severe leukopenia, which resolved after discontinuing trimethoprim-sulfamethoxazole and valganciclovir.  She does not use tobacco, alcohol, or illicit drugs.  Temperature is 38.9 C (102 F), blood pressure is 110/70 mm Hg, pulse is 114/min, and respirations are 22/min.  Physical examination shows bilateral lung crackles and diffuse abdominal tenderness.  Gross blood is seen on rectal examination.  Laboratory results are as follows:  Urinalysis is normal.  Chest x-ray reveals bilateral interstitial infiltrates.  Which of the following is the most likely cause of this patient's current condition?

Quizplus · Accepted Answer

Patients receiving solid organ transplantations require high-dose immunosuppressive medication to prevent organ rejection. This results in systemic immunosuppression, which puts them at risk for opportunistic infections, most notably Pneumocystis pneumonia (PCP) and cytomegalovirus (CMV). This patient was on prophylaxis for PCP (trimethoprim-sulfamethoxazole) and CMV (valganciclovir), but both medications were discontinued 2 months ago due to leukopenia. She now presents with pulmonary symptoms (dyspnea on exertion, dry cough), gastrointestinal symptoms (abdominal pain, diarrhea, hematochezia), pancytopenia, mild hepatitis, and interstitial infiltrates on chest x-ray. This combination of findings strongly suggests tissue-invasive CMV disease (causing pneumonitis, gastroenteritis, and hepatitis). Viremia can be detected in the blood using polymerase chain reaction (PCR) but may not always be present; tissue biopsy is the gold standard. Treatment involves discontinuing antimetabolite immunosuppression (eg, mycophenolate) and initiating antiviral therapy. Intravenous ganciclovir is used for patients with severe disease (eg, pneumonitis, meningoencephalitis, high viral loads, significant gastrointestinal disease). Patients with minimal signs and symptoms can take oral valganciclovir. (Choice A) Aspergillosis primarily causes pulmonary disease (fever, pleuritic chest pain, and hemoptysis), although it may involve other organs. Aspergillosis tends to cause nodules and focal infiltrates on chest x-ray (not bilateral interstitial infiltrates), and gastrointestinal disease is uncommon. (Choice B) Candida colonizes airways and usually does not cause pneumonia. Gastrointestinal disease is also uncommon. (Choice C) Cryptosporidium causes diarrhea in immunosuppressed patients but usually does not involve the lung. (Choice E) Influenza typically causes high fever, headache, malaise, and sore throat. Pneumonia is a common complication. Gastrointestinal disease (colitis), pancytopenia, and hepatitis are uncommon. (Choice F) Legionella often presents with high fever (>39 C [102.2 F]), gastrointestinal symptoms (eg, diarrhea), and pulmonary symptoms. However, bloody diarrhea is an unusual manifestation of legionellosis and CMV is a far more prevalent infection. If the CMV DNA PCR is negative, other less common causes (eg, Legionella) can be explored. (Choice G) Mycoplasma causes headache, fever, sore throat, and cough. It typically does not cause gastrointestinal symptoms. (Choice H) Pneumocystis pneumonia (PCP) is a common infection in solid organ transplant patients who do not receive prophylaxis. PCP presents with pulmonary symptoms (respiratory failure, cough, dyspnea) but typically does not cause gastrointestinal or hepatic issues. Educational objective: Patients who receive a solid organ transplant are at risk for opportunistic infections, most notably Pneumocystis pneumonia and cytomegalovirus (CMV). In the absence of prophylaxis, patients who present with a systemic illness involving multiple organ systems (eg, pneumonitis, hepatitis, gastroenteritis) should be tested for CMV.

A 45-Year-Old Woman Comes to the Emergency Department Due to 3