Vasculitis

Question

| Vasculitis Type | Affected Vessels | Clinical Features | Diagnostic Findings | Treatment | Clinical Significance | Populations Most Vulnerable |
|-----------------|-----------------|------------------|---------------------|-----------|----------------------|-----------------------------|
| Giant Cell (Temporal) Arteritis | Large and medium-sized arteries, especially temporal arteries | Headache, jaw claudication, visual disturbances, scalp tenderness | Elevated erythrocyte sedimentation rate (ESR), temporal artery biopsy | High-dose corticosteroids | Can lead to irreversible blindness if left untreated | Individuals over 50 years old, especially women |
| Takayasu Arteritis | Aorta and its major branches | Weak or absent pulses, blood pressure differences between arms, claudication, visual disturbances | Angiography, elevated ESR, aortic wall thickening | High-dose corticosteroids, immunosuppressive agents | Most commonly affects young women of Asian descent | 
| Polyarteritis Nodosa | Medium-sized arteries | Abdominal pain, weight loss, fever, hypertension, skin nodules | Angiography, biopsy showing segmental transmural inflammation | High-dose corticosteroids, immunosuppressive agents | Can lead to organ ischemia and infarction | Individuals of all ages, more common in males |
| Wegener Granulomatosis (Granulomatosis with Polyangiitis) | Small to medium-sized arteries, capillaries, and venules | Upper and lower respiratory tract involvement, glomerulonephritis, systemic symptoms | Positive c-ANCA (anti-neutrophil cytoplasmic antibody), biopsy showing necrotizing granulomas | High-dose corticosteroids, immunosuppressive agents | Can lead to severe organ damage and death if untreated | Peak incidence in middle-aged individuals |
| Microscopic Polyangiitis | Small vessels, including capillaries and venules | Glomerulonephritis, pulmonary involvement, systemic symptoms | Positive p-ANCA (anti-neutrophil cytoplasmic antibody), biopsy showing pauci-immune necrotizing vasculitis | High-dose corticosteroids, immunosuppressive agents | Associated with rapidly progressive glomerulonephritis | Individuals of all ages, more common in males |
| Churg-Strauss Syndrome (Eosinophilic Granulomatosis with Polyangiitis) | Small to medium-sized arteries, capillaries, and venules | Asthma, eosinophilia, systemic symptoms | Positive p-ANCA (anti-neutrophil cytoplasmic antibody), biopsy showing eosinophilic infiltrates | High-dose corticosteroids, immunosuppressive agents | Eosinophilic infiltration of multiple organs, especially the lungs | Asthmatic individuals, often with a history of allergies |
| Henoch-Schönlein Purpura | Small vessels, including capillaries and venules | Palpable purpura, arthralgia, abdominal pain, renal involvement | Clinical diagnosis, biopsy showing leukocytoclastic vasculitis | Supportive care, corticosteroids in severe cases | Most commonly affects children, often follows an upper respiratory infection |

Clinical significance:
- Giant Cell Arteritis: Urgent treatment is necessary to prevent irreversible vision loss.
- Takayasu Arteritis: Can lead to arterial stenosis, aneurysm formation, and organ ischemia if left untreated.
- Polyarteritis Nodosa: Can cause severe organ damage, including renal and gastrointestinal involvement.
- Wegener Granulomatosis: Can lead to respiratory failure and renal failure if not promptly treated.
- Microscopic Polyangiitis: Rapidly progressive glomerulonephritis is a significant complication.
- Churg-Strauss Syndrome: Asthma and eosinophilia are common features, and lung involvement can be severe.
- Henoch-Schönlein Purpura: Renal involvement can lead to long-term kidney damage.

Populations most vulnerable:
- Giant Cell Arteritis: Individuals over 50 years old, especially women.
- Takayasu Arteritis: Most commonly affects young women of Asian descent.
- Polyarteritis Nodosa: Individuals of all ages, more common in males.
- Wegener Granulomatosis: Peak incidence in middle-aged individuals.
- Microscopic Polyangiitis: Individuals of all ages, more common in males.
- Churg-Strauss Syndrome: Asthmatic individuals, often with a history of allergies.
- Henoch-Schönlein Purpura: Most commonly affects children, often follows an upper respiratory infection.

Please note that this table provides a general overview and additional details can be found in medical textbooks or resources specific to the USMLE Step 1.

Vasculitis Type	Affected Vessels	Clinical Features	Diagnostic Findings	Treatment	Clinical Significance	Populations Most Vulnerable
Giant Cell (Temporal) Arteritis	Large and medium-sized arteries, especially temporal arteries	Headache, jaw claudication, visual disturbances, scalp tenderness	Elevated erythrocyte sedimentation rate (ESR), temporal artery biopsy	High-dose corticosteroids	Can lead to irreversible blindness if left untreated	Individuals over 50 years old, especially women
Takayasu Arteritis	Aorta and its major branches	Weak or absent pulses, blood pressure differences between arms, claudication, visual disturbances	Angiography, elevated ESR, aortic wall thickening	High-dose corticosteroids, immunosuppressive agents	Most commonly affects young women of Asian descent
Polyarteritis Nodosa	Medium-sized arteries	Abdominal pain, weight loss, fever, hypertension, skin nodules	Angiography, biopsy showing segmental transmural inflammation	High-dose corticosteroids, immunosuppressive agents	Can lead to organ ischemia and infarction	Individuals of all ages, more common in males
Wegener Granulomatosis (Granulomatosis with Polyangiitis)	Small to medium-sized arteries, capillaries, and venules	Upper and lower respiratory tract involvement, glomerulonephritis, systemic symptoms	Positive c-ANCA (anti-neutrophil cytoplasmic antibody), biopsy showing necrotizing granulomas	High-dose corticosteroids, immunosuppressive agents	Can lead to severe organ damage and death if untreated	Peak incidence in middle-aged individuals
Microscopic Polyangiitis	Small vessels, including capillaries and venules	Glomerulonephritis, pulmonary involvement, systemic symptoms	Positive p-ANCA (anti-neutrophil cytoplasmic antibody), biopsy showing pauci-immune necrotizing vasculitis	High-dose corticosteroids, immunosuppressive agents	Associated with rapidly progressive glomerulonephritis	Individuals of all ages, more common in males
Churg-Strauss Syndrome (Eosinophilic Granulomatosis with Polyangiitis)	Small to medium-sized arteries, capillaries, and venules	Asthma, eosinophilia, systemic symptoms	Positive p-ANCA (anti-neutrophil cytoplasmic antibody), biopsy showing eosinophilic infiltrates	High-dose corticosteroids, immunosuppressive agents	Eosinophilic infiltration of multiple organs, especially the lungs	Asthmatic individuals, often with a history of allergies
Henoch-Schönlein Purpura	Small vessels, including capillaries and venules	Palpable purpura, arthralgia, abdominal pain, renal involvement	Clinical diagnosis, biopsy showing leukocytoclastic vasculitis	Supportive care, corticosteroids in severe cases	Most commonly affects children, often follows an upper respiratory infection