Assessment of patients with acute joint pain.
Is the Patient Systemically Ill?
Whenever a patient with acute joint pain also presents with fever, rigors, systemic symptoms, or signs of involvement of additional organ systems, careful evaluation is necessary to rule out potentially life-threatening processes such as infection or diffuse vasculitis. Hospitalization and consultation for evaluation of rheumatic or infectious disease are usually required for patients with arthritis and systemic symptoms. Obtain blood cultures, and perform the evaluation outlined below.
Is This Disseminated Gonococcal Infection?
In young adults, hematogenous gonococcal infection is one of the most common causes of acute arthritis. Arthritis may be the sole manifestation of disseminated gonococcal infection. Skin lesions are few and are found on the extremities, frequently around a joint, and are pustular or hemorrhagic, rarely bullous. Gram-stained smears of material contained in the pustules may reveal gram-negative diplococci within polymorphonu-clear neutrophils. Tenosynovitis classically involves tendons of the hand or foot. The primary (mucosal) site of gonococcal infection is often asymptomatic. If disseminated gonococcal infection is suspected, culture of blood and secretions from the pharynx, rectum, and urethra or cervix should be obtained.
Is There Arthritis on Joint Examination?
Ascertain by careful examination whether acute joint pain is due to an intra-articular process. Is there redness, diffuse warmth, effusion, or painful limitation of active and passive motion? If the joint is not involved, consider cellulitis, tenosynovitis, bursitis, or other periarticular lesions.
Is the Process Oligoarticular or Polyarticular?
Involvement of 1–3 joints in an asymmetric pattern is generally considered a characteristic of oligoarthritis, although this asymmetric involvement may occur early in some polyarticular conditions such as juvenile rheumatoid arthritis. Common causes of oligoarthritis include infection, crystal deposition (eg, gout), and trauma. The polyarthritis syndromes involve many joints, usually in a symmetric fashion.
If one of the affected joints is acrally located (eg, wrist, elbow, knee, ankle), arthrocentesis should be attempted in the emergency department, using local anesthesia and sterile technique (Chapter 6). A specialist and/or ultrasound guidance should be considered for arthrocentesis of the shoulders and hips. The joint fluid should be analyzed and the results should be used to classify the arthritis according to the scheme in Table 19–1.
Classification of Arthritis
Table 21–1. Classification of Abnormal Synovial Fluid. |Favorite Table|Download (.pdf)
Table 21–1. Classification of Abnormal Synovial Fluid.
|Type of Joint Fluid||Viscosity||Clarity||Color||Leukocyte Count (per μL)||Gram Stain and Culture||Other Findings|
|Noninflammatory (class I)||High||Clear||Light ...|