Differential Diagnosis for RA, Weight Loss, Scrotal Swelling, Fever, Night Sweats

• Single Most Likely Diagnosis
  • Rheumatoid Arthritis (RA) with Felty's Syndrome or Rheumatoid Vasculitis: This condition is a complication of long-standing RA, characterized by weight loss, fever, and other systemic symptoms. The scrotal swelling could be related to rheumatoid vasculitis affecting the testicular vessels.
• Other Likely Diagnoses
  • Tuberculosis (TB): TB can cause weight loss, fever, night sweats, and can also affect the scrotum (epididymitis or orchitis). It's known to exacerbate or mimic RA symptoms.
  • Lymphoma: Both Hodgkin's and non-Hodgkin's lymphoma can present with systemic symptoms like weight loss, fever, and night sweats. Lymphoma can also cause scrotal swelling if there is testicular involvement.
  • Sarcoidosis: This condition can mimic RA and cause systemic symptoms. It can also involve the testes, leading to scrotal swelling.
• Do Not Miss Diagnoses
  • Testicular Cancer: Although less likely, testicular cancer can cause scrotal swelling and systemic symptoms like weight loss and fever if it has metastasized. It's crucial not to miss this diagnosis due to its potential for cure with early treatment.
  • Endocarditis: Infective endocarditis can cause fever, weight loss, and night sweats. It might also lead to embolic phenomena, including scrotal swelling if an embolus affects the testicular vessels.
• Rare Diagnoses
  • Behçet's Disease: A rare condition that can cause a wide range of symptoms, including arthritis, fever, weight loss, and genital ulcers or swelling, which could potentially involve the scrotum.
  • Polyarteritis Nodosa (PAN): A systemic vasculitis that can cause a variety of symptoms, including weight loss, fever, and could potentially cause scrotal swelling if the testicular vessels are involved.