HERPES SIMPLEX VIRUS PNEUMONITIS IN AN IMMUNOCOMPETENT, CRITICALLY ILL HOST

Abstract

TOPIC: Chest Infections TYPE: Medical Student/Resident Case Reports INTRODUCTION: Pneumonitis due to herpes simplex virus is well reported in immunocompromised patients. It is extraordinarily uncommon in immunocompetent patients. CASE PRESENTATION: A 68 year old female with a history of chronic hypoxic respiratory failure on 2 Liters home oxygen presented to our facility with one day of dizziness and profound shortness of breath. At presentation, her oxygen saturation was 75%. A CT of the chest demonstrated significant bilateral diffuse infiltrates of ground glass appearance with consolidation. She was intubated and was transferred to the ICU. She had septic shock requiring vasopressors, and was started on community acquired pneumonia coverage with vancomycin, doxycycline, and ceftriaxone. She was extubated to high flow nasal canula and she was transferred to Step Down. On the floor, she failed to improve and required significant high flow nasal canula and bilevel positive airway pressure (BIPAP) support. A bronchoscopy was performed which showed that the lungs appeared normal. Cytopathology of bronchial washings showed positive staining for HSV-1. Transbronchial biopsy was also performed which demonstrated organizing pneumonia with focal nuclear atypia, findings suggestive of a viral pneumonitis. She was initiated on IV Acyclovir and was evaluated for immunocompromise, however, an extensive workup revealed no cause of compromise. She was noted to have perioral lesions consistent with herpes labialis which she reported started prior to her admission. She improved significantly after initiation of anti-viral therapy. DISCUSSION: Unfortunately, the signs and symptoms of herpes simplex pneumonitis are quite non specific, and in the intensive care setting, diagnosis can be obscured by positive HSV PCR on bronchial specimens in patients without HSV Pneumonitis. . A 2020 retrospective study showed that patients being treated for antibiotic-resistant ventilator associated pneumonia who were also found to have high levels of HSV DNA by PCR experienced a mortality benefit when treated with acyclovir. This finding suggests that HSV may be an underrepresented pathogen in immunocompetent hosts. Despite the vague nature of HSV pneumonitis, there are several features which can be suggestive. It should be considered in patients with disease resistant to antibacterial therapy, difficulty weaning from oxygen, and unexplained leukocytosis. Chest X-ray findings are nonspecific, but CT imaging usually shows ground glass opacities. CONCLUSIONS: Prior case reports have suggested that HSV pneumonitis in immunocompetent hosts occurs late in the course of illness and is associated with ventilator use. This case is significant as it represents HSV as a potential pathogen in immunocompetent patients at the onset of illness prior to initiation of invasive ventilation. REFERENCE #1: 1. Ishihara T, Yanagi H, Ozawa H, Takagi A. Severe herpes simplex virus pneumonia in an elderly, immunocompetent patient. BMJ Case Rep. 2018;2018:bcr2017224022. Published 2018 Jul 18. doi:10.1136/bcr-2017-224022 REFERENCE #2: 2. Schuierer L, Gebhard M, Ruf HG, et al. Impact of acyclovir use on survival of patients with ventilator-associated pneumonia and high load herpes simplex virus replication. Crit Care. 2020;24(1):12. Published 2020 Jan 10. doi:10.1186/s13054-019-2701-5 REFERENCE #3: 3. Pandita A, Dannheim K, Madhuripan N, Ehsan A, Farmakiotis D. Acute Necrotizing Pneumonia from Herpes Simplex Virus. Am J Med. 2021;134(2):e121-e122. doi:10.1016/j.amjmed.2020.06.050 DISCLOSURES: No relevant relationships by Jacob Gelman, source=Web Response No relevant relationships by Lucas Hamrick, source=Web Response No relevant relationships by Allison Lastinger, source=Web Response