A 55-year-old man comes to the office due to progressive abdominal pain. The pain is greatest after eating. The patient has also had 6 months of fatigue, joint pain, and weight loss. On examination, temperature is 38 C (100.4 F), blood pressure is 150/100 mm Hg, pulse is 80/min, and respirations are 14/min. Cardiopulmonary examination is normal. The abdomen is tender to palpation with no rigidity or rebound. Complete blood count is normal. CT angiography of the abdomen reveals bilateral renal infarcts and several abdominal arteries with microaneurysms and distal abrupt cutoffs. Blood cultures are negative for growth after 48 hours. Which of the following is the most likely diagnosis?

Question

A 55-year-old man comes to the office due to progressive abdominal pain.  The pain is greatest after eating.  The patient has also had 6 months of fatigue, joint pain, and weight loss.  On examination, temperature is 38 C (100.4 F), blood pressure is 150/100 mm Hg, pulse is 80/min, and respirations are 14/min.  Cardiopulmonary examination is normal.  The abdomen is tender to palpation with no rigidity or rebound.  Complete blood count is normal.  CT angiography of the abdomen reveals bilateral renal infarcts and several abdominal arteries with microaneurysms and distal abrupt cutoffs.  Blood cultures are negative for growth after 48 hours.  Which of the following is the most likely diagnosis?

Quizplus · Accepted Answer

11ec25c8_d882_080b_bc81_2bb5ac598f61_MD0003_00 This patient's abdominal angiography is consistent with polyarteritis nodosa (PAN), a systemic vasculitis of medium-sized muscular arteries. PAN causes segmental, transmural inflammation in the arterial wall and damages the internal and external elastic laminae, which results in arterial lumen narrowing and microaneurysms. Because luminal narrowing decreases distal blood flow and increases the risk of acute thrombosis, patients with PAN often present with symptoms of tissue ischemia or infarction. Arterial damage is usually most prominent in the kidneys, neurologic system, skin, and gastrointestinal tract. segmental, transmural inflammation Damage to the mesenteric vessels often causes mesenteric ischemia, which is marked by intermittent abdominal pain after eating, decreased food consumption, and weight loss; bowel wall necrosis may cause perforation. Review of systems frequently reveals weeks or months of preceeding nonspecific symptoms (eg, fever, myalgia, joint pains, fatigue) due to high levels of circulating inflammatory cytokines. Although biopsy is the gold standard for diagnosis, mesenteric angiography is often diagnostic in those with signs of significant mesenteric ischemia; it typically demonstrates microaneurysms, irregular arterial constrictions, and occlusions of distal artery branches in multiple abdominal arteries. Renal infarctions are also frequently seen. (Choice A) Severe atherosclerosis can cause renal infarction, mesenteric ischemia, and multiple mesenteric artery abnormalities. However, several months of preceding constitutional symptoms (eg, fever, joint pains) would be atypical. (Choice B) Septic emboli from bacterial endocarditis can cause infarctions of multiple organs and chronic nonspecific symptoms. However, the presence of negative bacterial cultures makes this diagnosis less likely. In addition, microaneurysms in the mesenteric vessels would be atypical. (Choice C) Fibromuscular dysplasia can cause arterial narrowing, aneurysms, and ischemia/infarction. It is common in the renal arteries and may occasionally cause mesenteric ischemia due to involvement of splanchnic vessels. However, it is most common in women (90% of cases), and months of preceding constitutional symptoms would be atypical. (Choice E) Thromboangiitis obliterans occurs primarily in young smokers and is generally marked by symptoms in the distal extremities (eg, finger ulcers, gangrene, infarction) due to the formation of inflammatory thrombi. Aneurysms would be atypical, and the mesenteric and renal vessels are not generally affected. Educational objective: Polyarteritis nodosa is marked by segmental, transmural inflammation of medium-sized arteries, which leads to luminal narrowing, thrombosis, and organ ischemia. The kidneys (eg, renal infarction) and gastrointestinal tract (eg, mesenteric ischemia, bowel perforation) are often affected. Mesenteric angiography typically reveals multiple arteries with microaneurysms, irregular luminal narrowing, and distal occlusions.

A 55-Year-Old Man Comes to the Office Due to Progressive