A 43-year-old man comes to the physician reporting acute-onset right knee pain. He was diagnosed with diabetes mellitus a year ago and takes metformin. He does not use tobacco, alcohol, or illicit drugs. The patient is in a monogamous relationship. His father also has diabetes. His temperature is 37 C (98.6 F), blood pressure is 134/86 mm Hg, pulse is 86/min, and respirations are 16/min. BMI is 26 kg/m². Physical examination shows a slightly swollen and tender right knee and mild hepatomegaly. Right knee x-ray reveals chondrocalcinosis and a moderate effusion. Appropriate analgesic is administered for joint pain. Which of the following is the best next step in management of this patient?

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11ec25c8_d50c_de53_bc81_25a48536ec6b_MD0003_00 This patient has acute monoarticular arthritis with chondrocalcinosis (calcified articular cartilage on radiographs), diagnostic of calcium pyrophosphate dihydrate crystal deposition (CPPD) disease (pseudogout). Patients with pseudogout should be evaluated for secondary causes such as hyperparathyroidism, hypothyroidism, and hemochromatosis. Given this patient's recently diagnosed diabetes mellitus and hepatomegaly, hereditary hemochromatosis (HH) is highly likely. HH-induced iron deposition in the synovial fluid appears to promote CPPD. Diabetes in HH appears to be due primarily to loss of insulin secretion and often requires injectable insulin; however, mild or early disease is frequently managed with oral agents. chondrocalcinosis The initial evaluation of HH includes serum iron studies, which will show increased levels of serum iron, ferritin, and transferrin saturation. The diagnosis can be confirmed with genetic testing for hemochromatosis-associated mutations (eg, HFE). Liver biopsy is not required but may be useful to stage the extent of liver involvement (eg, in patients with significant liver function test abnormalities) or to confirm the diagnosis in patients who have iron studies indicating iron overload but negative results on the classic HFE gene markers (Choice C). Long-term management of hemochromatosis involves serial phlebotomy to deplete excess iron stores. (Choices A and E) Chondrocalcinosis is not a typical feature of gout or rheumatoid arthritis (which is associated with anticitrullinated peptide antibodies). (Choice B) Antismooth muscle antibodies are seen in autoimmune hepatitis, which can be associated with other autoimmune disorders including type 1 diabetes mellitus, thyroid disease, and rheumatoid arthritis. Patients may develop a subacute, symmetric polyarthritis involving the small joints, but acute monoarthritis with chondrocalcinosis would not be seen. (Choice F) Slit-lamp eye examination is helpful in identifying the Kayser-Fleischer rings of Wilson disease. Wilson disease can cause hepatomegaly; however, it typically presents with neuropsychiatric manifestations, and almost all patients are diagnosed before age 35. Educational objective: Hereditary hemochromatosis is commonly associated with calcium pyrophosphate dihydrate crystal deposition in joints, leading to chondrocalcinosis, pseudogout, and chronic arthropathy. Patients commonly also have diabetes and liver disease. Diagnosis is suggested by iron overload on serum iron studies and can be confirmed by genetic tests. References: Hereditary hemochromatosis. (http://www.ncbi.nlm.nih.gov/pubmed/23418762) Characteristics of the arthropathy described in hereditary hemochromatosis. (http://www.ncbi.nlm.nih.gov/pubmed/21584944)

A 43-Year-Old Man Comes to the Physician Reporting Acute-Onset Right