A 66-year-old man is admitted to the hospital for left lower quadrant abdominal pain, fever, and vomiting. CT scan of the abdomen reveals diverticulitis. The patient is started on supportive care and antibiotics. His symptoms improve over 2 days; however, on the third day of hospitalization he reports acute pain in the right ankle, which becomes "unbearable" within a few hours. The patient had a similar pain 1 year ago that resolved with over-the-counter medication. Medical history is notable for type 2 diabetes, hyperlipidemia, and hypertension. His temperature is 37.1 C (98.8 F), blood pressure is 140/90 mm Hg, and pulse is 98/min. BMI is 36 kg/m². Examination shows a swollen, erythematous right ankle with moderate restriction of movement due to pain; the left ankle is normal. Both ankles were normal at the time of admission to the hospital. Which of the following is the most likely diagnosis?

Question

Quizplus · Accepted Answer

11ec25c8_d50b_30a0_bc81_03dafd398205_MD0003_00 This patient with acute, rapidly progressing ankle pain and a prior history of similar pain has acute gout. Although it is most common in the first metatarsophalangeal joint, gout can also involve the knee and ankle. Gout is characterized by recurrent attacks that typically develop overnight or early in the morning, reaching maximum intensity within 12-24 hours. Definitive diagnosis is obtained via synovial fluid analysis showing inflammatory cells and needle-shaped, negatively birefringent urate crystals. A gout attack can be precipitated by conditions that cause increased production or decreased elimination of uric acid, or an acute change in uric acid levels. Common triggers include heavy alcohol consumption, intake of urate-rich foods, trauma/surgery, dehydration, and medications that raise (eg, thiazide diuretics, cyclosporine) or lower (eg, allopurinol) uric acid levels. (Choices A and E) The spondyloarthropathies (eg, ankylosing spondylitis, psoriatic arthritis, reactive arthritis, enteropathic arthritis [associated with inflammatory bowel disease]) predominantly affect the axial skeleton. These disorders can cause acute peripheral oligoarthritis but it is typically less dramatic than gout. Most patients will have additional symptoms including low back pain and stiffness, and inflammation at tendon insertions (enthesitis). (Choice C) Neuropathic (Charcot) arthropathy causes destructive arthritis in patients with long-standing diabetes who have peripheral neuropathy. Although the ankle is commonly involved, obvious deformities and chronic pain are characteristic. (Choice D) Osteoarthritis most often causes chronic pain involving the knees, hips, and hands. Acute inflammatory flare-ups are unusual in the absence of a precipitating factor (eg, heavy overuse of the joint). (Choice F) Rheumatoid arthritis causes chronic inflammatory arthritis, most commonly affecting the metacarpophalangeal joints. Findings include stiffness and doughy swelling of the joints, rather than acute erythema and effusion. (Choice G) Septic arthritis is characterized by acute monoarticular arthritis, often with fever and chills. Onset occurs over days (not hours, as in this patient). Although often caused by hematogenous seeding from a concurrent infection, septic arthritis is more commonly due to gram-positive organisms rather than the gram-negatives and anaerobes implicated in diverticulitis. Educational objective: Gout typically presents as an acute monoarticular arthritis that quickly progresses to maximum intensity within 12-24 hours. Triggers include alcohol use, surgery/trauma, dehydration, and certain medications (eg, diuretics). References: Clinical features and risk factors of postsurgical gout. (http://www.ncbi.nlm.nih.gov/pubmed/17998214)

A 66-Year-Old Man Is Admitted to the Hospital for Left