Not Just an Opportunist

Introduction: Pneumocystis carinii pneumonia (PCP) is an opportunistic infection which can cause significant morbidity and mortality in immunocompromised patients if left untreated. It is much rarer in immunocompetent patients with more variable morbidity but similar mortality.


Description: A previously healthy 17-year-old female presented for evaluation of fever and dyspnea. Review of systems included 4 days of fevers with associated cough, shortness of breath and vomiting. Mother denied any recent travel outside New York, but reported the patient is a frequent hiker. Patient was reportedly sexually active with one partner. There was no history of drug use or vaping.
On arrival to the emergency room, she was hypoxic with saturations around 60% and hypotensive with a systolic pressure in the 80s and associated tachycardia. She was placed on supplemental oxygen but required escalation to bilevel noninvasive respiratory support with improvement of oxygen saturation to the mid 90s. Her chest x-ray was remarkable for bilateral middle and lower lobe opacities. She remained hypotensive despite fluids and vasoactives and was intubated in the pediatric intensive care unit for progressive septic shock.
Workup included a chest computed tomography scan which demonstrated nonspecific diffuse pulmonary parenchymal abnormality and pleural effusions. Her laboratory results were remarkable for elevated lactate dehydrogenase (LDH). Blood cultures and viral studies were negative. She ultimately underwent diagnostic bronchoscopy and was found to be PCP positive via indirect fluorescent antibody from the bronchial wash. Initial immunologic workup showed no evidence of immunocompromise and she was HIV negative. Trimethoprim-sulfamethoxazole and steroids were initiated, with clinical improvement leading to extubation and transfer out of the PICU.


Discussion: There are only 16 known cases of PCP pneumonia in an immunocompetent patient, all in adults. To our knowledge, this is the first documented case of an immunocompetent pediatric patient with PCP pneumonia. This case highlights that a high index of suspicion should be maintained even in previously healthy patients based on diagnostic evaluation; in this case elevated LDH and hypoxia out of proportion to imaging and symptoms.