Vasculitis: Pathological Classification
Vasculitis is the inflammation of blood vessel walls, typically categorized by the size of the affected vessels. These are high-yield topics for board exams due to their distinct clinical presentations.
1. Large-Vessel Vasculitis
| Disorder | Key Features |
|---|---|
| Giant Cell (Temporal) Arteritis | Elderly patients. Unilateral headache, jaw claudication, and visual disturbances. High ESR. Granulomatous inflammation. |
| Takayasu Arteritis | Young (< 40) Asian females. “Pulseless disease” (weak pulses in the upper extremities). Granulomatous inflammation of the aortic arch. |
2. Medium-Vessel Vasculitis
- Polyarteritis Nodosa (PAN): Transmural inflammation with fibrinoid necrosis. Involves many organs except the lungs. Associated with Hep B. Classic “string of pearls” appearance on angiography.
- Kawasaki Disease: Children < 4 years old. Fever, conjunctivitis, rash, strawberry tongue, and cervical lymphadenopathy. Risk of coronary artery aneurysm. Treat with IVIG and aspirin.
3. Small-Vessel Vasculitis (ANCA-associated)
Pathology Pearl:
- Granulomatosis with Polyangiitis (Wegener): C-ANCA (anti-PR3). Upper/lower respiratory tract + kidney.
- Microscopic Polyangiitis: P-ANCA (anti-MPO). Kidney + lungs, but no nasopharyngeal involvement.
- Eosinophilic Granulomatosis with Polyangiitis (Churg-Strauss): P-ANCA (anti-MPO). Asthma, eosinophilia, sinusitis.
4. Quick Board Pearls
- Henoch-Schönlein Purpura (HSP): Most common childhood vasculitis. IgA immune complex deposition. Triad: Palpable purpura (legs), abdominal pain, arthralgia. Follows URI.
- Buerger Disease (Thromboangiitis obliterans): Seen in heavy smokers. Segmental thrombosing vasculitis with vein/nerve involvement. Causes gangrene and claudication.