Differential Diagnosis for 22 y/o with Raised ANA Titer and Symptoms

• Single Most Likely Diagnosis

  • Systemic Lupus Erythematosus (SLE): This is the most likely diagnosis given the raised ANA titer, which is a common indicator of autoimmune diseases, particularly SLE. The symptoms of hand and feet swelling and trouble walking could be indicative of lupus nephritis or other systemic manifestations of SLE.

• Other Likely Diagnoses

  • Rheumatoid Arthritis (RA): Although RA typically presents with more symmetric joint involvement, the raised ANA titer and symptoms of swelling and difficulty walking could suggest an early or atypical presentation of RA.
  • Mixed Connective Tissue Disease (MCTD): This disease combines features of SLE, RA, and scleroderma, and a raised ANA titer is common. The symptoms described could fit within the spectrum of MCTD.
  • Sjögren's Syndrome: While primarily known for causing dry eyes and mouth, Sjögren's can also present with systemic symptoms including joint pain and swelling, and a significant proportion of patients have a positive ANA.

• Do Not Miss Diagnoses

  • Vasculitis (e.g., ANCA-associated vasculitis): Although less common, vasculitis can present with a wide range of symptoms including swelling and difficulty walking due to systemic inflammation. Missing this diagnosis could lead to severe complications.
  • Infectious Diseases (e.g., Endocarditis, Lyme Disease): Certain infections can cause a false-positive ANA and systemic symptoms. These conditions require prompt diagnosis and treatment to prevent serious outcomes.

• Rare Diagnoses

  • Scleroderma: Characterized by skin thickening and potentially systemic involvement, scleroderma can present with a positive ANA. However, the described symptoms are less typical for scleroderma.
  • Polymyositis/Dermatomyositis: These inflammatory myopathies can have a positive ANA and cause muscle weakness, which might contribute to difficulty walking. However, they are less likely given the specific symptoms of hand and feet swelling.
  • Autoimmune Hepatitis: Although primarily affecting the liver, autoimmune hepatitis can have extrahepatic manifestations and sometimes a positive ANA. It's a rare consideration but should be kept in mind, especially if liver function tests are abnormal.