Ease Into Prep with a PANCE^® Question of the Day

The correct answer is E. This patient has osteoarthritis. Clues to this diagnosis include the patient's risk factors, which include advanced age and obesity. The distribution of joints is also typical, with weight-bearing joints such as the hip and knee being affected together with the small joints of the fingers (DIPs and PIPs). The asymmetric involvement is common. Morning stiffness is seen but resolves in a short period of time, as opposed to that of rheumatoid arthritis. The more typical complaint is worsening joint pain with activity. Crepitus can be appreciated on physical examination of the involved joint. The common radiographic finding is unequal joint spaces with osteophyte formation.

Laboratory results are typically normal. Antinuclear antibodies (choice A) are not likely to be positive in this patient. It is best not to do antinuclear antibody testing in this patient, because it can be positive in up to 10% of patients who do not have any rheumatologic disease. A false positive result, therefore, might be confusing. Elevated erythrocyte sedimentation rate (choice B) and C-reactive protein, which are markers of inflammation, are not seen in the setting of osteoarthritis.

Joint erosions (choice C) are not seen with osteoarthritis. Rather, they are seen in rheumatoid arthritis, and if found, may be helpful in confirming that diagnosis.

Rheumatoid factor (choice D) would also be negative. Rheumatoid arthritis is more commonly symmetric in its joint involvement. This patient's history is not consistent with rheumatoid arthritis.

PEARL: Osteoarthritis is common in older, obese patients and involves weight-bearing joints, such as the knee and hip. Osteophytes and uneven joint spaces are characteristic on radiograph. A common physical finding is crepitus, described as a "crunching" feeling on palpation with simultaneous movement of the joint.