Monarthritis/Polyarthritis: Differential Diagnosis

Monarthritis/Polyarthritis: Differential Diagnosis

Stephen Ray Mitchell

John F. Beary III


  • The number of joints and the time course during which a joint disorder develops guide the approach to differential diagnosis. Acute and severe monarthritis, especially one that presents along with fever, may represent septic arthritis, which is a rheumatologic emergency. The promptness of the diagnosis and treatment of a potentially septic process is likely to profoundly alter the outcome.

  • Alternatively, a single abnormal inflamed joint that persists beyond 2 months presents a different diagnostic challenge, with infection being a much less likely
    disease process. In each case, one must view the overall clinical presentation, including factors such as extra-articular visceral involvement, constitutional signs and symptoms, severity of illness, limitation of function, potential foci of infection, skin lesions, hyperuricemia, and history of trauma or bleeding disorders.

    Table 14-1 Differential Diagnosis of Monarthritis by Presentation

    Monarthritis Common Less common
    Acute Bacterial arthritis Leukemia
    Gout (CPPD) Rheumatoid arthritis
    Spondyloarthropathies Sarcoid arthritis
    Reactive arthritis Hemarthrosis
    Psoriatic arthritis Coagulopathy
    Inflammatory bowel disease Dialysis/apatite crystals
    JIA Osteochondromatosis
    Anticoagulant therapy
    Chronic Osteoarthritis Fungal arthritis
    Spondyloarthropathies Tuberculous arthritis
    Lyme disease (recurring) Bacterial arthritis
    Monarticular RA
    Sarcoid arthritis
    CPPD, calcium pyrophosphate dihydrate; JIA, juvenile idiopathic arthritis; PVNS, pigmented villonodular synovitis; RA, rheumatoid arthritis.

  • Often, an aggressive initial approach is indicated, including joint aspiration with synovial fluid analysis and occasionally, in more refractory or unexplained situations, referral for synovial biopsy or arthroscopy. Therapy will vary significantly depending on the presumptive diagnosis. Specific therapy for each disease is discussed in later chapters. Tables 14-1 and 14-2 summarize the diagnostic approach to this group of disorders.


  • Infectious arthritis has an abrupt onset and a marked systemic inflammatory response. Because prompt therapy is required to prevent irretrievable joint damage, it is important to diagnose bacterial infection promptly. One may be deceived, however, in a partially treated patient on oral antibiotics or in an immunosuppressed patient in whom the inflammatory response is dampened by steroid therapy. A prudent approach includes careful examination for associated infectious foci and clinical clues (e.g., cutaneous pustules with neisserial infection), prompt joint aspiration and synovial fluid analysis, synovial fluid culture and Gram stain, and empiric antibiotics (depending on age and epidemiology). A viral process is typically polyarticular and may be accompanied by rash or other viral signs and symptoms. Lyme arthritis, caused by a Borrelia spirochete in endemic areas, can present acutely in recurring episodes of knee monarthritis; but more often it presents early in the course of the disease as migratory polyarthralgias, is associated with a characteristic rash or tick bite, and has a less “toxic” presentation (see Chapter 47).

  • Crystal-induced disease

    • Gout classically presents as “podagra” with the abrupt and intense onset of pain and inflammation in the first metatarsophalangeal joint; it often affects the midfoot and ankle, but can involve any joint or bursa. Typically, a man in his fifties with
      hypertension, obesity, diabetes, and coronary artery disease presents with monarthritis of the lower extremity. However, approximately 25% present with polyarticular synovitis. Between episodes, the joints return to normal unless chronic disease develops. A careful check for tophi on the ears, elbows, hands, or feet is required. At a younger age of onset of gout, one must think of lymphoma or other disorders associated with rapid cell turnover. The finding of negatively birefringent, needle-shaped crystals within the white blood cells in the synovial fluid is diagnostic. Note that gout can coexist with pseudogout, and both can coexist with infection (see Chapter 43).

      Table 14-2 Differential Diagnosis of Polyarthritis by Presentation

      Polyarthritis Common Less common

      Neisseria infection
      Acute rheumatic fever
      Lyme disease (early)

         Nonmigratory Rheumatoid arthritis
      Serum sickness
      Systemic lupus
      Polyarticular JIA
      Hematologic disorders
      Polyarticular gout
      Rheumatoid arthritis
      Polyarticular JIA
      Systemic lupus
      Polyarticular gout
      Oligoarticular OA
      Sarcoid arthritis
      CTD and overlap syndromes
      CTD, connective tissue disease; JIA, juvenile idiopathic arthritis; OA, osteoarthritis.

    • Calcium pyrophosphate dihydrate (CPPD) deposition disease (pseudogout) is an acute or subacute process in the elderly with involvement of large or small joints (including the second and third metacarpophalangeal joints). Chondrocalcinosis can often be defined radiographically in the knee, symphysis pubis, or triangular cartilage of the wrist. Crystals found within synovial fluid white blood cells are rhomboid-shaped and positively birefringent. In those patients who present at a younger age, other diagnostically important, treatable medical conditions, such as hemochromatosis or hyperparathyroidism must be considered (see Chapter 44).

  • Hemarthrosis is defined through the aspiration of bloody joint fluid.

    • Trauma usually is associated with a relevant history of injury. A layer of fat (from the bone marrow) seen on top of bloody fluid implies intra-articular fracture even in the presence of negative radiographs.

    • Internal derangement. Meniscal tears involving avascular portions of knee fibrocartilage may not be bloody but can cause intermittent locking, giving way, and a positive MacMurray’s maneuver (a painful click produced by extending the knee when the foot is internally or externally rotated). Instability of the collateral and cruciate ligaments is also a clue to this condition (see Chapter 24).

    • Nontraumatic hemarthrosis may be seen in the setting of anticoagulation, after the use of heparin during dialysis, or with benign neoplasms such as pigmented villonodular synovitis, synovial osteochondromatosis, or hemangioma of the synovium. Diagnosis of the latter three disorders is confirmed with synovial biopsy, arthroscopy, or magnetic resonance imaging (MRI).

  • Periarticular syndromes. Any of the tissues surrounding the joint can be involved in an inflammatory or traumatic process. A careful musculoskeletal examination can distinguish between tendinitis, bursitis, overuse syndromes, and surrounding cellulitis. Erythema nodosum is often seen with drug reaction, inflammatory bowel disease, or acute sarcoidosis. It often causes a periarthritis about the ankles and can result in an associated joint effusion. Osteomyelitis or neoplasia should be considered
    with focal bone pain. Severe nighttime periarticular pain in a child is uncommon with juvenile arthritis and should always suggest leukemia.

  • Noninfectious inflammatory conditions

Jul 29, 2016 | Posted by in RHEUMATOLOGY | Comments Off on Monarthritis/Polyarthritis: Differential Diagnosis
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