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Musculoskeletal complaints are extremely common in outpatient medical practice and are among the leading cause of disability and absenteeism from work. Pain in the joints must be evaluated in a uniform, thorough, and logical fashion to ensure the best chance of accurate diagnosis and to plan appropriate follow-up testing and therapy. Joint pain and swelling may be manifestations of disorders affecting primarily the musculoskeletal system or may reflect systemic disease.
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INITIAL ASSESSMENT OF A MUSCULOSKELETAL COMPLAINT
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Articular versus nonarticular: Is the pain located in a joint or in a periarticular structure such as soft tissue or muscle? (Fig. 47-1)
Inflammatory versus noninflammatory: Inflammatory disease is suggested by local signs of inflammation (erythema, warmth, swelling); systemic features (morning stiffness, fatigue, fever, weight loss); or laboratory evidence of inflammation (thrombocytosis, elevated ESR or C-reactive protein).
Acute (≤6 weeks) versus chronic.
Localized versus systemic.
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Age, sex, race, and family history
Symptom onset (abrupt or gradual), evolution (chronic constant, intermittent, migratory, additive), and duration (acute versus chronic)
Number and distribution of involved structures: monarticular (one joint), oligoarticular (two to three joints), polyarticular (more than three joints); symmetry
Other articular features: morning stiffness, effect of movement, features that improve/worsen Sx
Extraarticular Sx: e.g., fever, rash, weight loss, visual change, dyspnea, diarrhea, dysuria, numbness, weakness
Recent events: e.g., trauma, drug administration, travel, other illnesses
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Complete examination is essential: particular attention to skin, mucous membranes, nails (may reveal characteristic pitting in psoriasis), eyes. Careful and thorough examination of involved and uninvolved joints and periarticular structures; this should proceed in an organized fashion from head to foot or from extremities inward toward axial skeleton; special attention should be paid to identifying the presence or absence of:
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Warmth and/or erythema
Swelling
Synovial thickening
Subluxation, dislocation, joint deformity
Joint instability
Limitations to active and passive range of motion
Crepitus
Periarticular changes
Muscular changes including weakness, atrophy
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LABORATORY INVESTIGATIONS
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Additional evaluation usually indicated for monarticular, traumatic, inflammatory, or chronic conditions or for conditions accompanied by neurologic changes or systemic manifestations.
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For all evaluations: include CBC, ESR, or C-reactive protein
Where there are suggestive clinical features, include: rheumatoid factor, antibodies to cyclic citrullinated peptides (anti-CCPs), ANA, antineutrophil cytoplasmic antibodies (ANCA), antistreptolysin O titer, Lyme antibodies
Where systemic disease is present or suspected: renal/hepatic function tests, UA
Uric acid: useful only when gout diagnosed and therapy contemplated
CPK, aldolase: consider with muscle ...