Joint Pain—Atraumatic
Patients who present to the emergency department with a tender or swollen joint without a history of recent significant trauma require a careful evaluation. Although many of the disorders producing this symptom may be appropriately treated with immobilization, analgesics, and anti-inflammatory agents, the physician must ensure that bacterial infection is not present; this is true because staphylococcal, gonococcal, and pneumococcal organisms may rapidly destroy a joint if not promptly diagnosed and treated. For this reason, arthrocentesis is recommended in all patients in whom the diagnosis of septic arthritis cannot be excluded.
COMMON CAUSES OF JOINT PAIN AND SWELLING
Degenerative joint disease (DJD; osteoarthritis)*
Rheumatoid arthritis*
Gout*
Bursitis*
LESS COMMON CAUSES OF JOINT PAIN AND SWELLING NOT TO BE MISSED
Acute bacterial arthritis (staphylococcal, gonococcal, pneumococcal)*
Systemic lupus erythematosus
Pseudogout*
Acute rheumatic fever
Toxic synovitis*
Ruptured Baker cyst*
Osteochondrosis*
OTHER CAUSES OF JOINT PAIN AND SWELLING
Progressive systemic sclerosis
Ankylosing spondylitis
Psoriatic arthritis
Reiter syndrome
Neuropathic arthropathy
Pigmented villonodular synovitis
Synovioma
Hemangioma
Hemophilic arthropathy*
Osteochondromatosis
HISTORY
A history of severe pain and swelling in a single joint, especially the first metatarsophalangeal joint or knee, intolerably uncomfortable to even the slightest pressure, suggests gout or pseudogout. Migrating polyarthralgia and arthritis suggest acute rheumatic fever, rheumatoid arthritis, or systemic lupus erythematosus. A history of polyserositis, nasopharyngeal ulcers, Raynaud phenomenon, alopecia, or malar rash in association with atraumatic arthralgias and arthritis suggests systemic lupus erythematosus. Patients with an inflamed osteoarthritic joint usually give a history of chronic discomfort in the involved joint increased or precipitated by use and improving with rest or immobilization. A history suggestive of venereal disease should imply either gonococcal arthritis or Reiter syndrome.
PHYSICAL EXAMINATION
Joint swelling without erythema or impressive warmth is noted in patients with osteoarthritis. First metatarsophalangeal arthritis (podagra) is most commonly noted in gout, whereas knee arthritis (gonagra) is seen more commonly in pseudogout. A malar rash, nasopharyngeal ulcers, and alopecia in association with arthritis are seen in systemic lupus erythematosus. Limitations of chest wall expansion and lumbosacral spine flexion are found in ankylosing spondylitis, and psoriatic skin changes may be seen in patients with psoriatic arthritis. Discrete papules with hemorrhagic, purple, or darkened centers overlying the extension surfaces and often associated with a urethral or cervical discharge in a patient with a history of recent sexual exposure suggest gonococcal arthritis or tenosynovitis.
DIAGNOSTIC TESTS
Radiologic examination rarely provides a definitive diagnosis. Most commonly, the presence of soft-tissue swelling and an effusion, readily detected on physical examination, are simply confirmed radiologically. DJD, however, may be documented by roentgenograms of the involved joint. Uniform joint space narrowing, demineralization, and bony erosions suggest rheumatoid arthritis; linear calcium deposition within the joint space is noted in patients with pseudogout. Sacroiliac periostitis may be documented in patients with ankylosing spondylitis, and “pencil-in-cup” deformities are occasionally noted in the more advanced forms of psoriatic arthritis. Infrequently, “punched-out,” radiolucent, bony tophi may be noted in advanced gout.
The definitive diagnostic test, which should be performed in all patients presenting with an acute atraumatic synovitis or arthritis, is arthrocentesis. This procedure is essential to document the presence or absence of acute, destructive staphylococcal, gonococcal, or pneumococcal arthritis. When overlying cutaneous infection is not present, the peripheral joint may and should be aspirated with impunity by the physician in the emergency department. This is true except for the hip, the arthrocenteses of which should be performed by an orthopaedist with fluoroscopic guidance if necessary. Arthrocentesis should be performed after cleansing the skin and sterilizing the point at which the puncture will be made, after which the skin may then be anesthetized with lidocaine. The arthrocentesis itself follows, and the physician should attempt to remove as much fluid as possible from the joint. The fluid should
be examined for gross appearance, sent for culture and sensitivity, microscopically examined for Gram stain and cell count and differential, and glucose levels measured. Microscopic crystal analysis should also be performed with a polarizing lens to exclude gout and pseudogout. Table 47-1 indicates the results of synovial fluid analysis in each of four general classes of arthritis.
Additional laboratory tests that may be useful include a sedimentation rate, antinuclear antibodies, latex fixation, antistreptolysin O titer, blood cultures, and urethral, throat, cervical, and rectal cultures for Neisseria gonorrhoeae when indicated. Note that serum uric acid levels have not been found to correlate with the presence of acute gouty arthritis.
CLINICAL REMINDERS
Perform an arthrocentesis on or obtain orthopaedic consultation for all patients with an atraumatic joint effusion in whom the diagnosis of septic arthritis is possible.
Do not administer intra-articular steroids to any patient in whom an acute infectious arthritis is suspected.
Begin empiric intravenous antibiotics in any patient in whom the possibility of acute infectious arthritis exists once synovial and blood cultures have been obtained.
SPECIFIC DISORDERS
Degenerative Joint Disease
DJD is a chronic arthropathy characterized by degeneration of cartilage and bony hypertrophy at articular margins. The inflammatory response to these degenerative changes is usually minimal but occurs with sufficient frequency and intensity to produce common “acute-on-chronic” flairs of this disorder. DJD occurs as a primary process, most commonly affecting the distal interphalangeal joints, the first metacarpophalangeal joint, the knee, and the cervical and lumbar spines. It may also occur secondarily in response to severe or chronic articular injury.
Diagnosis
The onset of symptoms in patients with DJD is typically insidious. Joint stiffness is a prominent early feature evolving into pain on motion of the joint that is relieved with rest. The physical examination in primary DJD may reveal Heberden nodes (distal interphalangeal joint), Bouchard nodes (proximal interphalangeal joint), or crepitus of the shoulders, first metacarpophalangeal joint, and patella (seen with osteomalacia patellae in young women). Acute flairs are associated with periarticular swelling, effusion, increased warmth, and minimal or absent erythema. No signs or symptoms of an acute systemic illness are seen in chronic DJD, and laboratory tests are unrevealing. Radiologic studies typically demonstrate nonuniform narrowing of the joint space with local osteophyte formation, marginal bone lipping, dense subchondral bone, and occasionally bony cysts.
Treatment
Temporary immobilization or rest of the involved joint, the application of local heat, analgesics, and anti-inflammatory agents are all useful in providing symptomatic relief. Although at present no cure exists for the unremitting process of degeneration, conservative measures usually provide significant symptomatic relief for patients with acute exacerbations.
Table 47-1 Results of Synovial Fluid Analysis in Four Classes of Arthritis | |||||||||||||||||||||||||
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