A 55-year-old man is admitted to the hospital due to abdominal discomfort and black stools. Medical history includes asthma and hypertriglyceridemia, for which the patient takes the appropriate medications. He has smoked a pack of cigarettes daily for 30 years and used intravenous drugs in the past. The patient is treated empirically with a proton pump inhibitor; upper gastrointestinal endoscopy does not reveal a source for the pain or bleeding. Symptoms resolve without further intervention, and he is discharged. Several weeks later, the patient returns to the emergency department with fever, weight loss, and muscle pain. After initial evaluation, muscle biopsy demonstrates transmural inflammation of medium-sized arteries with areas of amorphous, eosin-staining arterial wall necrosis. Areas of disruption of the internal elastic lamina are also present. Which of the following is the most likely predisposing factor for this patient's current condition?

Question

A 55-year-old man is admitted to the hospital due to abdominal discomfort and black stools.  Medical history includes asthma and hypertriglyceridemia, for which the patient takes the appropriate medications.  He has smoked a pack of cigarettes daily for 30 years and used intravenous drugs in the past.  The patient is treated empirically with a proton pump inhibitor; upper gastrointestinal endoscopy does not reveal a source for the pain or bleeding.  Symptoms resolve without further intervention, and he is discharged.  Several weeks later, the patient returns to the emergency department with fever, weight loss, and muscle pain.  After initial evaluation, muscle biopsy demonstrates transmural inflammation of medium-sized arteries with areas of amorphous, eosin-staining arterial wall necrosis.  Areas of disruption of the internal elastic lamina are also present.  Which of the following is the most likely predisposing factor for this patient's current condition?

Quizplus · Accepted Answer

11ec160b_3a63_e7f3_9249_17eae9ac70fb_MD0001_00 This patient's biopsy is consistent with polyarteritis nodosa (PAN), a systemic vasculitis of medium-sized muscular arteries. Patients with PAN typically present with weeks or months of constitutional symptoms (eg, malaise, weight loss, myalgia, fever) and signs of tissue ischemia in the kidneys, skin, gastrointestinal tract, and/or neurologic system. Bleeding complications may occur due to the formation of microaneurysms from arterial wall weakening. Biopsy of affected areas generally reveals segmental, transmural inflammation with fibrinoid necrosis (amorphic, eosinophilic material in vessel wall) and disruption of the internal and external elastic laminae. In contrast to many other forms of vasculitis, PAN is not associated with antineutrophil cytoplasmic antibodies or significantly elevated antinuclear antibody titers. However, inflammatory markers (eg, C-reactive protein, erythrocyte sedimentation rate) are generally high. Although many cases of PAN have no clear inciting factor, up to a third of patients have underlying viral hepatitis B or C. In these individuals, PAN is likely triggered by the deposition of immune complexes (viral antigen bound by host antibody) in the arterial wall. (Choice A) Cutaneous small-vessel (leukocytoclastic) vasculitis is frequently triggered by antibiotic use. This condition is also mediated by immune complexes and often causes fibrinoid necrosis of the vessel wall. However, most cases are marked by palpable purpura and disease is limited to small (not medium-sized) vessels. (Choice B) Eosinophilic granulomatosis with polyangiitis (formerly Churg-Strauss syndrome) causes asthma and allergic rhinosinusitis. Biopsy generally shows eosinophilic infiltration in the vessel wall with granulomas. Small arteries and veins are primarily affected, and antineutrophil cytoplasmic antibodies are often positive. (Choice C) Severe hypertriglyceridemia can cause abdominal pain due to acute pancreatitis, but transmural vascular inflammation with fibrinoid necrosis would be atypical. (Choice D) Thromboangiitis obliterans (Buerger disease) occurs primarily in young smokers and is marked by limb claudication or digital ulcers. Biopsy typically shows highly cellular, inflammatory thrombi in small- to medium-sized vessels of the extremities; there is limited involvement of the vessel wall (eg, intact internal elastic lamina, no fibrinoid necrosis). Educational objective: Polyarteritis nodosa (PAN) is a systemic vasculitis characterized by constitutional manifestations and ischemic symptoms in the kidneys, skin, gastrointestinal tract, and neurologic system. Biopsy will show segmental, transmural arterial inflammation with fibrinoid necrosis and damage to the internal and external elastic lamina. PAN is often associated with underlying viral hepatitis B and C. __________ References: Polyarteritis nodosa. (http://www.ncbi.nlm.nih.gov/pubmed/29489258)

A 55-Year-Old Man Is Admitted to the Hospital Due to Abdominal