Differential Diagnosis for Small Joint Pain Evaluation

When evaluating small joint pain, it's crucial to consider a wide range of potential causes to ensure accurate diagnosis and appropriate treatment. The differential diagnosis can be organized into the following categories:

• Single Most Likely Diagnosis
  • Osteoarthritis (OA): This is often the most common cause of small joint pain, especially in older adults. OA is characterized by the wear and tear of joint cartilage, leading to pain, stiffness, and limited mobility. The small joints of the hands and feet are frequently affected.
• Other Likely Diagnoses
  • Rheumatoid Arthritis (RA): An autoimmune disorder that causes inflammation and pain in the joints. Small joints are typically involved early in the disease process, and symptoms are often symmetric.
  • 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. However, gout can also affect small joints in the hands and feet.
  • Psoriatic Arthritis (PsA): A condition that combines the swollen, scaly skin of psoriasis with joint pain and arthritis. It can affect any joint, but often involves the small joints of the hands and feet.
• Do Not Miss Diagnoses
  • Septic Arthritis: A medical emergency where a joint becomes infected, leading to severe pain, swelling, and potential destruction of the joint if not promptly treated. While less common, it's critical to consider this diagnosis due to its serious consequences.
  • Lyme Arthritis: Caused by the bacterium Borrelia burgdorferi, transmitted through the bite of an infected tick. It can cause joint pain and swelling, particularly in the knees, but can also affect smaller joints.
• Rare Diagnoses
  • Hemochromatosis: A genetic disorder characterized by excessive iron accumulation in the body, which can lead to joint pain among other symptoms. The small joints of the hands can be involved, mimicking OA.
  • Sarcoidosis: A condition where inflammatory cells form lumps known as granulomas in various parts of the body, including the joints. It can cause pain and stiffness in the small joints, though this is less common.
  • Relapsing Polychondritis: A rare autoimmune disorder that can cause cartilage inflammation, leading to joint pain and other symptoms. While it more commonly affects the cartilage of the ears, nose, and trachea, it can also involve the joints.

Each of these diagnoses has distinct features and requires careful consideration based on the patient's history, physical examination, and diagnostic tests to ensure an accurate diagnosis and appropriate management plan.