A 44-year-old man comes to the emergency department due to worsening abdominal pain and vomiting. The patient has had 3 months of fatigue, mild abdominal pain, low-grade fever, and joint pains. On examination, the abdomen is diffusely tender to palpation with rigidity and rebound. Urgent laparotomy reveals bilateral renal infarcts and multiple segments of necrosis and perforation in the small bowel. Microscopic examination of the vessel walls shows diffuse inflammation of the adventitia and marked thickening of the inner layers due to proliferation of loose connective tissue; the arterial lumen is significantly narrowed. Which of the following is the most likely diagnosis?

Question

A 44-year-old man comes to the emergency department due to worsening abdominal pain and vomiting.  The patient has had 3 months of fatigue, mild abdominal pain, low-grade fever, and joint pains.  On examination, the abdomen is diffusely tender to palpation with rigidity and rebound.  Urgent laparotomy reveals bilateral renal infarcts and multiple segments of necrosis and perforation in the small bowel.  Microscopic examination of the vessel walls shows diffuse inflammation of the adventitia and marked thickening of the inner layers due to proliferation of loose connective tissue; the arterial lumen is significantly narrowed.  Which of the following is the most likely diagnosis?

Quizplus · Accepted Answer

11ec160b_3a65_bcb4_9249_7303bf1bf906_MD0001_00 This patient's systemic symptoms, renal/small-bowel infarctions, and biopsy findings are consistent with polyarteritis nodosa (PAN), a systemic vasculitis of medium-sized muscular arteries. PAN is generally marked by the following: Segmental, transmural inflammation of the arterial wall with invasion of neutrophils and monocytes Destruction of the inner portion of the arterial wall; the normal architecture is replaced with necrotic fibrinoid material and loose connective tissue, which narrows the vessel lumen and increases the risk of thrombosis and tissue infarction. Destruction of the internal and external elastic laminae, which increases the risk of microaneurysms and subsequent rupture Patients with PAN generally present with weeks or months of nonspecific constitutional symptoms (eg, weight loss, fatigue, low-grade fever, arthralgias) and signs of tissue ischemia in the kidneys (eg, renal infarction), gastrointestinal tract (eg, small-bowel infarction, mesenteric ischemia), peripheral nerves, and/or skin. Because PAN is not associated with antineutrophilic cytoplasmic antibodies or significant elevation in antinuclear antibodies, diagnostic confirmation usually requires tissue biopsy. (Choices A and C) Bacterial endocarditis can cause embolic septic infarctions in the kidneys and intestines. Inherited coagulation disorders can also cause thrombosis with tissue infarctions. However, biopsy would show a clot/embolism in the arterial lumen (during acute infarction), not transmural inflammation and connective tissue proliferation. (Choice B) Granulomatosis with polyangiitis usually causes manifestations in the upper/lower airways (eg, rhinosinusitis, hemoptysis) and kidneys (eg, glomerulonephritis). The gastrointestinal tract is not typically affected. Furthermore, biopsy generally reveals a leukocytoclastic vasculitis with minimal or no luminal narrowing or fibrinoid necrosis. (Choice E) Thromboangiitis obliterans occurs primarily in young smokers. It is marked by inflammatory thrombi in the small- and medium-sized vessels of the extremities. Patients usually have digital ulcers, ischemia, gangrene, or limb claudication. Mesenteric and renal infarction would be atypical. In addition, transmural inflammation/connective tissue proliferation would not be seen during the acute stage of infarction. Educational objective: Polyarteritis nodosa is a systemic vasculitis of medium-sized muscular arteries marked by segmental, transmural, arterial wall inflammation with fibrinoid necrosis. This narrows the arterial lumen and increases risk of thrombosis and tissue ischemia/infarction. Damage to the internal and external elastic laminae also increases the risk of microaneurysm. Tissue damage primarily occurs in the kidneys, gastrointestinal tract, neurologic system, and skin; the lungs are usually spared.

A 44-Year-Old Man Comes to the Emergency Department Due to Worsening