A 42-year-old man comes to the office for evaluation of worsening joint pain and deformity. The patient initially experienced intermittent pain in his feet 2 years ago, which has progressed to constant pain in the knees and hands. Several months ago, he noticed nodular growths around the hand joints. Over-the-counter analgesics, taken as needed, provide some symptom relief. The patient did not see a physician earlier because he lost medical insurance after he became unable to work as an auto mechanic, but he recently got a new job. Physical examination shows joint swelling and deformities, as shown below. Range of motion of the finger joints is limited, and the patient has difficulty making a fist. Which of the following is the most likely underlying cause of this patient's current condition?

Question

A 42-year-old man comes to the office for evaluation of worsening joint pain and deformity.  The patient initially experienced intermittent pain in his feet 2 years ago, which has progressed to constant pain in the knees and hands.  Several months ago, he noticed nodular growths around the hand joints.  Over-the-counter analgesics, taken as needed, provide some symptom relief.  The patient did not see a physician earlier because he lost medical insurance after he became unable to work as an auto mechanic, but he recently got a new job.  Physical examination shows joint swelling and deformities, as shown below.  Range of motion of the finger joints is limited, and the patient has difficulty making a fist.  Which of the following is the most likely underlying cause of this patient's current condition?

Quizplus · Accepted Answer

This patient has tophaceous gout. Gout occurs in the setting of hyperuricemia and is characterized by the precipitation of monosodium urate (MSU) crystals in synovial spaces. In most cases, it initially affects the first metatarsophalangeal joints and knees, where it causes an episodic, inflammatory monoarthritis. Persistent hyperuricemia can result in chronic gout with tophi formation. Tophi are characterized by excessive MSU deposition in the joints or soft tissues, leading to a chronic inflammatory reaction and nodular deformities of the affected tissue; an erosive arthropathy may occur. Tophi are virtually pathognomonic for chronic gout and typically involve the joints of the hands and feet; multiple areas may be involved with severe disease. Other characteristic sites include the ears, tendons, and olecranon bursa. nodular deformities In contrast to acute gouty arthritis, which is exquisitely painful, tophi are generally painless. Aspiration demonstrates a white, chalky material, with high levels of MSU crystal visible on microscopy; x-ray may show erosion of the adjacent bone. (Choice A) Rheumatoid arthritis (RA) predominantly involves the small joints of the hands and feet. In contrast to gout, which initially causes acute monoarthritis, RA is usually polyarticular and symmetric from disease onset. Rheumatoid nodules (firm, nontender, subcutaneous nodules) may occur in the fingers but are more common at pressure points (eg, elbows, forearms). (Choice B) Pseudogout (calcium pyrophosphate dihydrate crystal arthritis) is an acute arthritis resembling gout. However, it is typically monoarticular and usually affects the knee or wrist; involvement of the interphalangeal joints is atypical. In addition, it usually affects individuals age >60. (Choice C) Hereditary hemochromatosis (excessive iron absorption with tissue deposition of hemosiderin) can cause a chronic arthritis affecting the hands. However, it does not cause tophi and is typically associated with other manifestations (eg, hyperpigmentation, cirrhosis, diabetes mellitus). (Choice D) Osteoarthritis is promoted by excessive or asymmetric mechanical joint stresses. It can cause periarticular osteophytes (eg, Heberden and Bouchard nodes) in the hands. However, patients typically have stiffness, and initial presentation in the feet is unexpected; in addition, joint deformities typically occur over a prolonged period (years). Heberden and Bouchard nodes Educational objective: Gout initially causes an episodic monoarthritis typically affecting the first metatarsophalangeal joints and knees. Persistent hyperuricemia can lead to tophaceous gout, which is characterized by excessive monosodium urate deposition, leading to chronic inflammation and nodular deformity. Tophi commonly involve the joints of the hands and feet; soft tissue involvement may also occur. References: Diagnosis, treatment, and prevention of gout. (http://www.ncbi.nlm.nih.gov/pubmed/25591183)

A 42-Year-Old Man Comes to the Office for Evaluation of Worsening