Which of the following conditions is least likely to cause joint pains with polyarticular involvement: Septic arthritis, Systemic Lupus Erythematosus (SLE), Henoch-Schönlein Purpura (HSP), or Dermatomyositis?

Joint Pains with Polyarticular Involvement: Differentiating Features

Septic arthritis is the least likely condition to present with polyarticular joint involvement among the options listed, as it typically manifests as monoarticular arthritis affecting a single joint.

Characteristics of Each Condition

Septic Arthritis

• Typically presents as monoarticular (single joint) involvement rather than polyarticular pattern 1
• When polyarticular involvement occurs, it's rare and usually seen in specific circumstances such as:
  • Immunocompromised patients
  • Intravenous drug users
  • Patients with underlying joint disease 1
• Characterized by acute onset, severe pain, marked inflammation, erythema, and joint swelling 2
• Usually accompanied by systemic symptoms like fever and malaise 1

Systemic Lupus Erythematosus (SLE)

• Commonly presents with polyarticular joint involvement 1
• Typically symmetric polyarthritis affecting small and large joints 1
• Joint pain is often associated with morning stiffness and inflammatory symptoms 2
• Extra-articular manifestations include skin rash, photosensitivity, renal involvement, and serositis 1
• Laboratory findings include positive ANA, anti-dsDNA antibodies, and low complement levels 1

Henoch-Schönlein Purpura (HSP)

• Frequently presents with polyarticular joint involvement 1
• Arthralgia or arthritis typically affects the knees and ankles 1
• Associated with characteristic palpable purpuric rash, predominantly on lower extremities 1
• Other manifestations include abdominal pain, gastrointestinal bleeding, and nephritis 1
• More common in children than adults 1

Dermatomyositis

• Commonly presents with polyarticular joint involvement in 27.5% of cases 3
• Can manifest as either oligoarthritis or polyarthritis 3
• Characterized by proximal muscle weakness, skin rash (heliotrope rash, Gottron papules) 4, 5
• Arthritis is often concurrent with the characteristic musculocutaneous manifestations 3
• Extra-articular manifestations include interstitial lung disease and potential association with malignancy 5, 6
• Laboratory findings include elevated muscle enzymes (CK, aldolase) and myositis-specific autoantibodies 2, 4

Key Differentiating Features

• Pattern of joint involvement:

  • Septic arthritis: Predominantly monoarticular 1
  • SLE, HSP, and Dermatomyositis: Commonly polyarticular 1, 3

• Clinical course:

  • Septic arthritis: Acute, rapidly progressive, requires emergency treatment 1
  • SLE, HSP, and Dermatomyositis: Usually subacute or chronic course 1, 5

• Response to treatment:

  • Septic arthritis: Requires antibiotics and often surgical drainage 1
  • SLE, HSP, and Dermatomyositis: Responsive to immunosuppressive therapy 2, 5, 6

Clinical Pearls

• When evaluating polyarticular joint pain, consider disease chronology, presence of inflammation, distribution pattern, extra-articular manifestations, and patient demographics 1
• Inflammatory arthritis typically presents with morning stiffness, joint swelling, and elevated inflammatory markers 2
• Dermatomyositis patients with arthritis may not show significant clinical or serological differences from those without arthritis, though males may be more commonly affected 3
• In dermatomyositis, arthritis generally responds favorably to treatment of the underlying disease without developing articular sequelae 3