Case Presentation: We present the case of a 65-year-old male with no previous smoking or supplemental oxygen history who presented to the emergency department after routine clinic visit that was ultimately found to have cryptogenic organizing pneumonia from Influenza type B. Past medical history was insignificant except for recent hospital admission the week prior that entailed a recent bilateral embolic stroke followed by a carotid endarterectomy, as well as a viral infection with Influenza type B. Initial evaluation upon admission revealed acute hypoxemic respiratory failure without hypercapnia. CT chest showed significant bilateral consolidation in the lower lobes indicating a bilateral pneumonia secondary to recent viral illness. Meropenem and Levaquin were started, followed by Vancomycin as the patient continued to require more oxyen and non-invasive ventilation over the following two days. Respiratory viral panel was negative, and tests for other possible causes, including fungal were negative. Patient underwent an EBUS where obtained samples were negative for cytology, gram stain and sputum findings. There was concern for noninfectious organizing pneumonia as other diagnoses had been excluded. The patient was then started on IV steroids, along with nightly CPAP. The patient’s oxygen requirements began to improve following this regimen over the course of several days, and was eventually transitioned to PO steroids with instructions for slow taper upon discharge.

Discussion: Cryptogenic organizing pneumonia (COP) is a clinicopathological syndrome that is comprised of systemic symptoms with consolidations on imaging with restrictive deficits on PFT’s and granulation tissues found in the airways [1]. There are many causes of this noninfectious pneumonia, with one well-documented cause being Influenza type A [2]. A much less noted cause is Influenza type B, with only one other case presented in the literature [3]. Our case represents a rare presentation not widely reported in the literature of cryptogenic organizing pneumonia secondary to Influenza type B. It also emphasizes the importance of gathering any history relative to any preceding upper respiratory viral illness when suspecting a pneumonia. The incidence of subsequent pneumonia in hospitalized patients have been shown to have either A or B is 68.6% and 56.9% respectively [4]. Early treatment with steroids is highly effective, but there can still be relapse after cessation [3]. With COP being a clinical diagnosis of exclusion, we are forced to add another layer of complexity to initial presentation and diagnosis.

Conclusions: When working up acute respiratory failure in an otherwise healthy patient presenting with suspected pneumonia, identifying a preceding viral illness in the context of minimal improvement on standard therapy may help evaluate a presentation of COP.