Differential Diagnosis for Inflammation

Given the referral to rheumatology due to unknown causes of inflammation, the differential diagnosis can be broad. Here's an organized approach:

• Single Most Likely Diagnosis

  • Rheumatoid Arthritis (RA): This is a common condition that causes inflammation in the joints, leading to pain, swelling, and potentially long-term damage. The referral to rheumatology suggests that RA or a similar autoimmune condition is being considered.

• Other Likely Diagnoses

  • Osteoarthritis: Although primarily a degenerative condition, osteoarthritis can cause significant inflammation, especially in advanced stages.
  • Psoriatic Arthritis: This condition combines the swollen, scaly skin of psoriasis with joint pain and arthritis symptoms.
  • Lupus: Systemic lupus erythematosus is an autoimmune disease that can cause inflammation in various parts of the body, including the joints, skin, and organs.
  • Gout: Characterized by sudden, severe attacks of pain, swelling, redness, and tenderness, often in the joint at the base of the big toe.

• Do Not Miss Diagnoses

  • Septic Arthritis: A potentially life-threatening condition that requires immediate medical attention, characterized by joint pain and swelling due to a bacterial or fungal infection.
  • Vasculitis: Inflammation of the blood vessels, which can lead to organ damage and is critical to diagnose early.
  • Cancer (e.g., lymphoma): Certain types of cancer can cause systemic inflammation and should be considered, especially if other symptoms like weight loss or night sweats are present.
  • Sarcoidosis: An inflammatory disease that affects multiple organs in the body, but most often the lungs and lymph glands.

• Rare Diagnoses

  • Relapsing Polychondritis: A rare disease characterized by recurrent episodes of cartilage inflammation.
  • Mixed Connective Tissue Disease: An autoimmune disease that combines features of lupus, scleroderma, and rheumatoid arthritis.
  • Eosinophilic Granulomatosis with Polyangiitis (Churg-Strauss Syndrome): A rare autoimmune condition that causes blood vessel inflammation.
  • Adult-Onset Still’s Disease: A rare inflammatory disorder that can cause fever, joint pain, and swelling, among other symptoms.

Each of these diagnoses has a different set of symptoms and diagnostic criteria, and a thorough medical evaluation, including history, physical examination, laboratory tests, and sometimes imaging studies, is necessary to determine the underlying cause of the inflammation.