Question

A 45-year-old man is admitted to the hospital with fever, weakness, weight loss, muscle and testicular pain, and a rash on his legs. He states that his symptoms began about 1 week ago. The testicular pain began about 1 day ago and has increased significantly over the last 24 hours. He denies recent illness or injury and states that has been in good health for as long as he can remember. On physical exam, the patient was well-developed, well-nourished, and in mild physical distress. His blood pressure was elevated at 152/94 mm Hg, and a chest radiograph was negative. Laboratory analysis revealed an elevated sedimentation rate and C-reactive protein, elevated BUN, and creatinine. His red blood cell count was decreased, and his ANCA was negative. An arteriogram showed diffuse arterial saccular aneurysms and narrowing of the arteries.

What is the most likely cause of this patient's symptoms?

Systemic lupus erythematosus
2 Polyarteritis nodosa
3 Rheumatoid arthritis
4 Sjögren syndrome
5 Kawasaki disease

Answer 1

The patient's combination of symptoms and laboratory results suggests that the most likely cause is Polyarteritis nodosa (PAN), a condition not typically associated with positive ANCA, which helps distinguish it from other similar conditions.

Step-by-step explanation:

Considering the patient's symptoms of fever, weight loss, muscle pain, testicular pain, and leg rash, combined with the laboratory findings of elevated sedimentation rate, C-reactive protein, elevated BUN, creatinine, decreased red blood cell count, and arteriogram results showing diffuse arterial saccular aneurysms and narrowing of the arteries, the most likely cause of this patient’s symptoms is Polyarteritis nodosa (PAN).

The negative ANCA test helps to differentiate PAN from other vasculitides such as Microscopic polyangiitis and Granulomatosis with polyangiitis, which are ANCA positive. In comparison, Systemic Lupus Erythematosus would typically have a positive ANA and more pronounced system-wide symptoms such as butterfly rash and arthritis. Rheumatoid arthritis and Sjögren syndrome would also not account for the detailed vascular findings seen in an arteriogram, and Kawasaki disease primarily affects children.