A Flu That Freed the Lungs When a Common Infection Leads to an Unexpected Discovery

Document Type

Conference Proceeding

Publication Date

10-2025

Publication Title

Chest

Abstract

INTRODUCTION: Pulmonary Hypertension (PH) is a serious condition that frequently goes undiagnosed until its late stages. For that reason, there must be a high index of suspicion when evaluating patients with exertional dyspnea and reduced exercise capacity. Frequently, acute respiratory illnesses can unmask underlying pulmonary pathology and thus lead to diagnostic reevaluation. We present the case of a patient with chronic hypoxic respiratory failure (baseline 2 liters oxygen via nasal cannula) who presented with concomitant influenza A and Mycoplasma pneumoniae infections, initially treated for heart failure, and eventually found to have PH. This diagnosis led to in-hospital initiation of targeted management which led to discharge without supplemental oxygen for the first time in years. CASE PRESENTATION: A 58 year old female non-smoker with a history of right renal transplant and chronic hypoxic respiratory failure presented to the hospital with dyspnea, productive cough, and fever. Vital signs were otherwise stable. Initial work-up yielded a positive influenza A (H1N1), elevated Mycoplasma IgM and she was started on empiric antibiotics. BNP was elevated to 1022, chest x-ray showed bilateral pulmonary vascular congestion. Point of care ultrasound (POCUS) on admission showed diffuse B-lines and jugular venous distention to the mandible. She was given intravenous furosemide 40 mg either daily to twice daily pending physical examination and POCUS findings. Despite eventual euvolemia, she remained persistently hypoxic, particularly with exertion. She underwent transthoracic echocardiogram which showed left ventricular ejection fraction of 70%, estimated right ventricular systolic pressure of 95-100mmHg, severe tricuspid regurgitation, and grade 1 diastolic dysfunction. She then underwent right heart catheterization which showed mean right atrial pressure of 1mmHg, pulmonary artery pressure of 83/18mmHg (mean 41mmHg), pulmonary capillary wedge pressure of 4mmHg and an estimated peripheral vascular resistance of 9.9 Wood units. These findings were consistent with pre-capillary pulmonary arterial hypertension. Further evaluation included a CT angiogram of the chest which was negative for pulmonary embolism, lower extremity duplex negative for DVT, positive anti-CCP and ANA without clinical evidence of rheumatoid arthritis. She was subsequently started on sildenafil 20 mg three times daily for group 1 PH. Within the following days, she was weaned off of supplemental oxygen to room air and discharged home. DISCUSSION: In most cases, we predominantly see acute illnesses exacerbating underlying conditions. This case shows that with careful diagnostic evaluation, acute illnesses may actually lead to improvement in pre-existing disease. Our patient's longstanding oxygen dependence and volume overload were thought to be due to a combination of heart failure and possible parenchymal lung disease. Even after being outside the infectious window and achieving euvolemia, she was not able to weaned off oxygen. As demonstrated, further diagnostic testing may be needed in such cases, and at times right heart catheterization is necessary to guide further management if PH is suspected. CONCLUSIONS: This case highlights the value of reconsidering the etiology of chronic hypoxia when conventional treatments fail. Timely recognition of pulmonary arterial hypertension followed by targeted intervention may not only improve symptoms, but also enhance quality of life in patients with chronic oxygen dependence.

Volume

168

Issue

4S

First Page

6853A

Comments

American College of Chest Physicians CHEST Annual Meeting, October 19-22, 2025, Chicago, IL

Last Page

6854A

DOI

10.1016/j.chest.2025.07.3841

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