Answer
A: Fibromyalgia
Educational Objective
Diagnose fibromyalgia in a man in the absence of discrete tender points.
Critique
The most likely diagnosis is fibromyalgia. The characteristic features of fibromyalgia are widespread chronic pain, fatigue, and/or sleep disorders, which are frequently accompanied by impaired cognitive function, mood disorders, and symptoms such as headache, gastrointestinal symptoms, and paresthesia. Although this patient initially appears to have specific joint symptoms, he is actually experiencing widespread (including nonarticular) pain. This widespread pain, together with poor/nonrestorative sleep, fatigue, and cognitive dysfunction (in this case, difficulty concentrating), is consistent with fibromyalgia. The absence of tender points is not relevant; men with fibromyalgia frequently do not experience tender points, and tender points are no longer included in fibromyalgia classification criteria. Other features experienced by patients (bowel symptoms, anxiety/depression, low-grade fever, low-titer/borderline antinuclear antibodies) are not diagnostic of fibromyalgia but are consistent with its presence.
The clinical manifestations of hypothyroidism include fatigue, cold intolerance, constipation, weight gain, impaired concentration, dry skin, edema, depression, mood changes, muscle cramps, and myalgia. A normal thyroid-stimulating hormone level excludes hypothyroidism.
This patient's physical examination demonstrates full range of motion of the joints without crepitus, making osteoarthritis less likely. Additionally, osteoarthritis cannot explain his diffuse body pain, difficulty sleeping, chronic fatigue, bowel symptoms, headache, and difficulty concentrating.
Rheumatoid arthritis (RA) is characterized by pain and swelling in multiple (>3) small joints of the hands and/or feet, along with morning stiffness lasting at least 1 hour. Initial symptoms often worsen gradually over weeks to months. RA frequently interferes with activities of daily living, including occupational and recreational activities. Constitutional symptoms such as increased fatigue and malaise are common. Depression and myalgia may occur and, less often, fever, anorexia, and weight loss. Physical examination reveals tenderness and swelling of the joints, sometimes with warmth and erythema; symmetric joint involvement is common. This patient lacks the synovitis characteristic of RA.
Key Point
The characteristic features of fibromyalgia are widespread chronic pain, fatigue, and sleep disorders, which are frequently accompanied by impaired cognitive function, mood disorders, and symptoms such as headache, gastrointestinal symptoms, and paresthesia.
Bibliogrpahy
Clauw DJ. Fibromyalgia: a clinical review. JAMA. 2014;311:1547-55. [PMID: 24737367] doi:10.1001/jama.2014.3266
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