Differential Diagnosis for Arthritis Starting from the First Carpometacarpal Joint and Spreading to the Whole Hand

• Single most likely diagnosis
  • Osteoarthritis (OA): This is the most likely diagnosis because OA commonly affects the first carpometacarpal joint, leading to pain and stiffness, and can progress to involve other joints in the hand.
• Other Likely diagnoses
  • Rheumatoid Arthritis (RA): Although RA typically starts with symmetric small joint involvement, it can initially present with prominent first carpometacarpal joint symptoms and then spread to other hand joints.
  • Psoriatic Arthritis (PsA): PsA can cause asymmetric joint involvement and may start in a single joint, including the first carpometacarpal joint, before spreading to other joints in the hand.
• Do Not Miss diagnoses
  • Septic Arthritis: Although less common, septic arthritis is a medical emergency that requires prompt diagnosis and treatment. It can start in any joint, including the first carpometacarpal joint, and spread to other joints if not treated.
  • Crystal Arthropathies (Gout or Pseudogout): These conditions can cause sudden, severe joint pain and swelling, often starting in a single joint. They are important to diagnose because they require specific treatments.
• Rare diagnoses
  • Hemochromatosis: This genetic disorder can lead to iron accumulation in joints, causing arthritis that might start in the first carpometacarpal joint and spread to other joints.
  • Wilson's Disease: A rare genetic disorder that can cause copper accumulation in the body, leading to liver, brain, and other organ damage, including arthritis that might affect the hands.