Vasculitis & Glomerular Master (Exhaustive)

I. Systemic Vasculitis

Large-Vessel Vasculitis

Disease	Epidemiology & Risk	Pathology & Mechanism	Clinical Presentation	Step 1 High-Yield Labs/Rx
Giant Cell (Temporal) Arteritis	Elderly females (>50). Associated with Polymyalgia Rheumatica.	Granulomatous inflammation of branches of the carotid artery.	Unilateral headache, jaw claudication, tenderness over temporal artery. Vision loss (ophthalmic artery occlusion).	↑ ESR/CRP. Rx: High-dose corticosteroids immediately. Biopsy: Intimal fibrosis, giant cells.
Takayasu Arteritis	Asian females < 40 years old.	Granulomatous thickening and narrowing of the aortic arch.	"Pulseless disease" (weak upper extremity pulses), fever, night sweats, skin nodules.	↑ ESR. Rx: Corticosteroids.

Medium-Vessel Vasculitis

Disease	Epidemiology & Risk	Pathology & Mechanism	Clinical Presentation	Step 1 High-Yield Labs/Rx
Polyarteritis Nodosa (PAN)	Young adults. Strong association with Hepatitis B (HBsAg+).	Transmural inflammation with fibrinoid necrosis. Lesions of *different ages* ("string of pearls").	Fever, weight loss, GI pain, melena. Renal HTN. Spares the lungs.	Negative ANCA. Angiogram: microaneurysms. Rx: Corticosteroids, cyclophosphamide.
Kawasaki Disease	Asian children < 4 years old.	Necrotizing vasculitis with mucocutaneous lymph node syndrome.	CRASH and Burn: Conjunctivitis, Rash, Adenopathy, Strawberry tongue, Hand/foot changes, Fever > 5 days.	Complication: Coronary artery aneurysms. Rx: IVIG + Aspirin.
Buerger Disease	Heavy smokers, males < 40.	Segmental thrombosing vasculitis extending into veins/nerves.	Intermittent claudication, Raynaud. Gangrene of digits.	Rx: Smoking cessation.

Small-Vessel Vasculitis

Disease	Epidemiology & Risk	Pathology & Mechanism	Clinical Presentation	Step 1 High-Yield Labs/Rx
Granulomatosis with Polyangiitis (Wegener)	Middle-aged males.	Triad: Necrotizing vasculitis, Granulomas (lung/airway), Glomerulonephritis.	Nasopharyngeal (perforated septum), Hemoptysis, Hematuria (RPGN).	c-ANCA (PR3-ANCA). CXR: Nodules. Rx: Cyclophosphamide.
Microscopic Polyangiitis (MPA)	No specific gender.	Necrotizing vasculitis (no granulomas).	Similar to Wegener but no nasopharyngeal and no granulomas. Palpable purpura.	p-ANCA (MPO-ANCA).
Churg-Strauss	History of atopy/asthma.	Granulomatous, necrotizing vasculitis with eosinophilia.	Asthma, sinusitis, neuropathy (wrist drop).	p-ANCA (MPO-ANCA). IgE elevated, Eosinophilia.
Henoch-Schönlein Purpura	Children, post-URI.	Vasculitis 2° to IgA deposition.	Triad: Palpable purpura (buttocks), Arthralgias, GI pain.	Renal Biopsy: Mesangial IgA. Rx: Supportive.

II. Glomerular Diseases

Nephritic Syndrome

Disease	LM/IF/EM Findings	Clinical / Associations
PSGN	LM: Hypercellular. IF: "Starry sky" (Lumpy-bumpy) IgG/C3. EM: Subepithelial humps.	Children, 2-4 wks post-Strep. Cola-colored urine. ↓ C3.
RPGN	LM: Crescents (fibrin/macrophages).	Rapid deterioration. Goodpasture (Linear IF), Wegener (Pauci-immune).
Goodpasture Syndrome	IF: Linear IgG/C3 deposition.	Hemoptysis + Hematuria (Renal Failure). Anti-GBM antibodies. Young males.
DPGN	LM: "Wire looping". EM: Subendothelial deposits.	SLE (Lupus Nephritis).
IgA Nephropathy	IF: IgA deposits in mesangium.	Episodic hematuria concurrent with URI/GI infection.
Alport Syndrome	EM: "Basket-weave" GBM.	X-linked. Mutation in Type IV collagen. Deafness + Eye problems.
MPGN	LM: "Tram-track". Type I: Hep B/C. Type II: C3 Nephritic Factor.	Mixed Nephritic/Nephrotic.

Nephrotic Syndrome

Disease	LM/IF/EM Findings	Clinical / Associations
Minimal Change Disease	EM: Effacement of foot processes.	Children. Excellent response to steroids.
FSGS	LM: Segmental sclerosis. EM: Effacement of foot processes.	African Americans, HIV, Heroin, Sickle Cell.
Membranous Nephropathy	EM: "Spike and dome" (subepithelial). Anti-PLA2R.	Caucasian adults. Hep B/C, SLE, Tumors.
Diabetic Nephropathy	LM: Kimmelstiel-Wilson nodules.	Hyperfiltration injury. Rx: ACE inhibitors.
Amyloidosis	Congo Red: Apple-Green Birefringence.	Associated with Multiple Myeloma or Chronic Inflammation.