Patient With a Rash, Abdominal Pain, and Weight Loss

Abstract

A 49-YEAR-OLD MAN PRESENTS WITH RIGHT ILIAC FOSSA PAIN OF 36 HOURS’ duration. He reports loss of appetite, weight loss, and increasing lethargy over the preceding 10 months with intermittent constipation but no other symptoms. He describes asymmetric altered sensation in his distal lower limbs with left worse than right. The patient smokes, has a history of illicit amphetamine and cannabinoid use, and acquired tattoos in a correctional facility. Past medical history is remarkable for an idiopathic splenic infarction 6 months ago. On physical examination, he is cachectic and he has right iliac fossa tenderness and percussion tenderness. He has a demarcated, erythematous maculopapular rash across his torso and limbs (FIGURE 1). Neurological examination reveals an asymmetric lower limb sensory neuropathy. Laboratory findings include leukocytosis (whitebloodcells, 16 900/μL), elevated inflammatorymarkers (C-reactiveprotein,109g/L; erythrocyte sedimentationrate, 27 mm/h), elevated rheumatoid factor (269 IU/L), low C3 and C4 (0.24 and 0.05 g/L, respectively), and a low titer of atypical perinuclear antineutrophil cytoplasmic antibody(ANCA),not selective foreitherproteinase3ormyeloperoxidase.Doublestranded DNA and extractable nuclear antibodies are negative. Cryoglobulins and serology for human immunodeficiency virus, hepatitis B, and hepatitis C are negative. Renal function is normal with normal urinary sediment. Abdominal computed tomographyrevealsmild thickeningof theascendingcolonandthepreviouslydocumented splenic infarction (FIGURE 2). What Would You Do Next?