Abstract Introduction Herpes Simplex virus (HSV) is a rare cause of pneumonitis which can be severe and fatal, especially in the immunocompromised or critically ill patient. It is often caused by reactivation of HSV which can present as a viral pneumonia and even acute respiratory distress syndrome (ARDS). Here we present a fatal case of an immunocompetent patient who presented with severe ARDS associated with HSV-1 pneumonitis detected via bronchoscopy. Case A 61-year-old male with past medical history of aortic stenosis status post bioprosthetic valve repair and obstructive sleep apnea presented to the hospital for progressive dyspnea and fatigue. On arrival, the patient was found to be hypoxic, requiring high flow nasal cannula, and eventually upgraded to ICU for mechanical ventilation (MV) due to respiratory distress. CT chest was notable for extensive scattered ground glass opacities in bilateral lung fields. Echocardiogram was unremarkable. Patient was treated with broad spectrum antibiotics with vancomycin, cefepime and azithromycin. Additionally, the patient was started on pulse dose steroids for concern of an acute exacerbation of ILD; the patient was later determined to have acute interstitial pneumonia. Respiratory viral panel and cultures were initially unremarkable. Cell count on bronchoalveolar lavage (BAL) was neutrophilic (92%). Patient was extubated after 10 days; however, he required reintubation less than 48 hours later due to worsening respiratory distress. He underwent a second bronchoscopy and BAL, which was negative for bacterial, viral and fungal elements. A third BAL and endobronchial ultrasound (EBUS) was performed three days later which resulted in a positive HSV1 PCR and cytology consistent with HSV1. Despite re-initiation of broad spectrum antibiotics and acyclovir, the patient continued to deteriorate from a respiratory standpoint and ultimately transitioned to comfort care. Discussion In immunocompetent adults, HSV is often a latent virus established in the neural ganglia after primary infection. Reactivation is triggered by immunosuppression or systemic or local stressors, often presenting in oral or gential ulcers. Although detection of HSV in BAL specimens often represents contamination from oral HSV reactivation, prior studies and case reports show that HSV infection was also found in the lungs of critically ill patients, especially those with prolonged MV. Mortality can exceed 60%. Our case brings to light an incidence of HSV pneumonitis in an ICU patient who had received pulse dose steroids earlier in his admission. Further studies examining the utility of early testing for HSV in critically ill patients are warranted. This abstract is funded by: None
Matta et al. (2026) studied this question.