Microscopic polyangiitis (MPA) is a rare condition characterized by nonspecific symptoms of fatigue, fever, or loss of appetite and additional symptoms related to areas of involvement. The rarity of the disease and its variable presentation can delay its diagnosis in the acute setting, potentially leading to delay in effective treatment and poor outcomes. This is a case report of a 68-year-old man, who presented to the hospital after being found poorly responsive at home. He was sedated and intubated in the field and brought to the ER. He was found to be hypotensive. History revealed abdominal aortic aneurysm, but no known history of GI bleed or use of blood-thinners. Physical exam revealed rhonchi throughout both lung fields, a soft, nondistended abdomen with normoactive bowel sounds, and cool extremities with weak palpable pulses. CBC was suggestive of anemia. BUN and creatinine were elevated indicating kidney injury. CT abdomen showed no acute pathology and an intact abdominal aortic aneurysm. CT chest revealed left lower lobe atelectasis and bilateral pulmonary edema. CT head was consistent with watershed infarction. Numerous blood transfusions were given. However, slow decline in hemoglobin continued to occur. Colonoscopy was considered for possible identification of the source of bleeding, however was not performed due to the family’s wish for conservative management. Bronchoscopy was performed, revealing extensive mucus plugging and bloody plugs. He was eventually weaned off sedation but remained largely unresponsive, occasionally opening his eyes to stimuli. On hospital day 7, necrotic lesions were noted on the patient’s ear and fingers. These findings prompted serologic studies for vasculitis that resulted in positive p-ANCA and myeloperoxidase antibodies, consistent with MPA. He was started on pulse dose IV steroids resulting in modest improvement in renal parameters and hemoglobin, but no discernible change in neurological status. The patient was transitioned to comfort care and palliative extubation was performed. Four days later, the patient expired. This case illustrates the potential for hypovolemic shock as a consequence of undiagnosed vasculitis. In this case, a definite diagnosis was not made, due to inability to perform a lung biopsy because of patient being on comfort measures. However, given that he was p-ANCA and myeloperoxidase positive, along with visualized blood on bronchoscopy, a presumptive diagnosis of MPA can be made. Although this patient may not have recovered even with early immunosuppressive treatment, vasculitis should be considered as a differential diagnosis in patients presenting in hypovolemic shock, especially if history, exam and noninvasive testing are unrevealing.