Review Question - QID 106190

The patient's symptoms, medical history, and biopsy findings are most consistent with polyarteritis nodosa (PAN).

PAN is a vasculitis of medium sized-vessels involving the kidney, nervous system and GI tract. Notably, it is unique among vasculitides in that it classically does not affect the pulmonary vasculature. The mesenteric vasculature is often involved and can lead to ischemic colitis or mesenteric ischemia due to diminished blood flow (e.g. post-prandial abdominal pain and hematochezia, as in this patient). Like many other vasculitides, the kidneys are often affected, with glomerulonephritis developing as a result of immune complex deposition. On the USMLE exams, it is often paired with a history of hepatitis B or HIV infection. Diagnosis is made by biopsy of involved tissue or via mesenteric angiography. Hypertension, mononeuritis multiplex, and livedo reticularis are common in affected patients.

Stanton et. al discuss the diagnosis and management of polyarteritis nodosa. They note the varied clinical manifestations, including mesenteric ischemia and glomerulonephritis.

Figure A shows the circumferential infiltrate of polymorphonuclear leukocytes and resulting intimal proliferation typical of PAN.

Illustration A reviews the vasculitides and the types of vessels they affect.

Incorrect Answers:
Answer 1: Churg-Strauss syndrome is notable for eosinophilic and granulomatous inflammation often involving the respiratory tract. It commonly presents with signs and symptoms similar to asthma.

Answer 2: Giant cell (temporal) arteritis is a large-vessel vasculitis of arteries above the clavicles. It most commonly presents in elderly patients, especially elderly females with a history of polymyalgia rheumatica.

Answer 3: Granulomatosis with polyanginitis is distinguished from PAN by pulmonary involvement. 90% of patients with active disease are anti-PR3 ANCA (also referred to as c-ANCA) positive. It often presents with chronic sinusitis and pulmonary symptoms such as hemoptysis.

Answer 4: Microscopic polyangiitis is distinguished from PAN by the presence of microscopic vessel involvement, especially skin, lung, and glomerular vessels. 70% of patients are anti-MPO ANCA (also known as p-ANCA) positive.

Bullet Summary:
Polyarteritis nodosa is a necrotizing vasculitis affecting medium-sized vessels of the skin, GI tract and kidneys that often presents with glomerulonephritis and symptoms related to ischemic colitis.