Differential Diagnosis for Vasculitis

The differential diagnosis for vasculitis is broad and can be categorized based on the likelihood and potential impact of missing a diagnosis. Here's a structured approach:

• Single Most Likely Diagnosis
  • Giant Cell Arteritis (GCA): This is often considered due to its relatively high prevalence among vasculitides, especially in patients over 50 years old, presenting with symptoms like temporal headaches, jaw claudication, and visual disturbances.
• Other Likely Diagnoses
  • Polyarteritis Nodosa (PAN): A medium-vessel vasculitis that can present with systemic symptoms such as fever, weight loss, and hypertension, along with specific organ involvement like renal or gastrointestinal symptoms.
  • Wegener's Granulomatosis (Granulomatosis with Polyangiitis, GPA): Characterized by the triad of respiratory tract granulomas, vasculitis, and glomerulonephritis, making it a consideration in patients with upper and lower respiratory symptoms along with renal involvement.
  • Microscopic Polyangiitis (MPA): Presents with renal and pulmonary involvement, often without granulomas, and is a common cause of ANCA-associated vasculitis.
• Do Not Miss Diagnoses
  • Kawasaki Disease: Although more common in children, it can occur in adults and is critical to diagnose early due to the risk of coronary artery aneurysms.
  • Takayasu Arteritis: A large-vessel vasculitis that can lead to significant morbidity if not recognized, particularly in young women, presenting with symptoms like arm claudication, reduced pulses, and hypertension.
  • ANCA-Associated Vasculitis (AAV): This includes conditions like GPA, MPA, and Eosinophilic Granulomatosis with Polyangiitis (EGPA), which are critical to diagnose due to their potential for severe organ damage and response to specific treatments.
• Rare Diagnoses
  • Eosinophilic Granulomatosis with Polyangiitis (EGPA, Churg-Strauss Syndrome): Characterized by asthma, eosinophilia, and vasculitis, making it a rare but important consideration in patients with atopic history and systemic vasculitis symptoms.
  • Primary Central Nervous System Vasculitis (PCNSV): A rare condition that can mimic other neurological diseases, making diagnosis challenging but crucial due to its treatment implications.
  • Cryoglobulinemic Vasculitis: Associated with cryoglobulins and can be related to hepatitis C infection, lymphoproliferative disorders, or autoimmune diseases, presenting with skin, renal, and neurological manifestations.

Each of these diagnoses has distinct clinical features, laboratory findings, and imaging characteristics that guide the diagnostic process. A thorough history, physical examination, and appropriate diagnostic tests are essential for accurately diagnosing vasculitis and initiating targeted therapy.