Differential Diagnosis for Joint Pain

• Single most likely diagnosis:
  • Osteoarthritis: This is the most common cause of joint pain, especially in older adults, due to wear and tear of the joint cartilage.
• Other Likely diagnoses:
  • Rheumatoid Arthritis: An autoimmune disorder that causes inflammation and pain in the joints, often affecting hands and feet.
  • Gout: A form of inflammatory arthritis characterized by sudden, severe attacks of pain, swelling, redness, and tenderness in one or more joints, most often the big toe.
  • Fibromyalgia: A long-term condition characterized by widespread pain in the muscles and bones, areas of tenderness, and general fatigue.
  • Bursitis or Tendinitis: Inflammation of the fluid-filled sacs (bursae) or tendons, often caused by repetitive motion or direct blows to a joint.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):
  • Septic Arthritis: A potentially life-threatening condition where the joint space becomes infected, requiring immediate medical attention.
  • Lyme Disease: A bacterial infection spread by ticks, which can cause joint pain and swelling, especially in the knees.
  • Cancer (e.g., multiple myeloma, bone metastases): Although rare, cancer can cause joint pain and should be considered, especially if there are other systemic symptoms like weight loss or fever.
• Rare diagnoses:
  • Psoriatic Arthritis: A form of arthritis that affects some people who have psoriasis, causing joint pain, stiffness, and swelling.
  • Lupus: An autoimmune disease that can cause joint pain and inflammation, among other symptoms.
  • Hemochromatosis: A genetic disorder causing the body to absorb too much iron, leading to joint pain and other complications.
  • Sarcoidosis: A condition where inflammatory cells form lumps known as granulomas in various parts of the body, including joints, causing pain and stiffness.