These are a group of small-vessel Vasculitis typically associated with presence of ANCA autoantibodies.

Granulomatosis with polyangiitis (GPA)

GPA is a distinct entity characterized by granulomatous vasculitis of the upper and lower respiratory tracts with glomerulonephritis, however virtually any organ can be involved. Very rare, seen more in White populations, 1:1 male to female ration, and can be seen at any age of life. The mean age of onset is 40 years, and less than 1/6 patients are affected in adolescence.

Pathology and Pathogenesis

Clinical Manifestations

Airway Involvement

Upper airway involvement occurs in 95% of patients with GPA. This can include paranasal sinus pain and drainage and purulent or bloody nasal discharge, nasal mucosal ulcerations. Nasal septal perforation leads to saddle nose deformity. Serous otitis media secondary to eustachian tube blockage. Subglottic tracheal stenosis in 1/6 of patients can lead to severe airway obstruction.

Lower pulmonary involvement can manifest as asymptomatic infiltrates, or clinically as cough with hemoptysis, dyspnea, chest discomfort. This is present in 85-90% of patients. Endobronchial disease can lead to obstruction with atelectasis.

Renal Involvement

Present in 77% of patients, and generally dominates the clinical picture. If untreated, this accounts for most of the mortality in this disease. It can range from a smoldering mild GN, but once clinically detectable renal failure occurs, rapidly progressive renal failure generally ensues unless treatment is initiated.

Systemic Symptoms

Arthralgias and arthritis. Malaise, weakness, fever, cough, weight loss.

Secondary Infections

Upper airway secondary infections can manifest as similar symptoms or as isolated fever.

Other Organ Involvement

Lab Findings

Inflammatory markers (CRP, ESR) will be elevated. There is often mild anemia and leukocytosis and thrombocytosis, mild hypergammaglobulinemia (particularly IgA), and mildly elevated rheumatoid factor.

90% of patients with active GPA have a positive PR3-ANCA (c-ANCA). In the absence of active disease, this drops to 60-70%. A small percentage of GPA patients have MPO-ANCA (p-ANCA) disease, and 20% of patients lack ANCA.

Diagnosis of GPA

Diagnosis is histopathologically made by demonstrtation of necrotizing granulomatous vasculitis on tissue biopsy in a patient with compatible clinical features. Lung tissue has the highest diagnostic yield. upper airway tissue may not show the vasculitis. Renal biopsy confirms the presence of pauci-immune GN (no immune complexes).

Role of ANCA. If active GN is present, the specificity of positive PR3 ANCA is very high. The presence of ANCA should be adjunctive and should not substitute for a tissue diagnosis with only rare exceptions. ANCA can be falsely positive in infectious and malignant diseases.

Differential Diagnosis

  1. Other vasculitides: anti GBM, relapsing polychondritis, histoplasmosis, mucocutaneous leishmaniasis
  2. Midline destructive diseases:
    1. Upper airway cancers, specifically extranodal NK/TC lymphoma
    2. Cocaine-induced tissue injury
    3. Levamisole-induced vasculitis (associated with cocaine, and granulocytopenia)
    4. Lymphomatoid granulomatosis

Treatment of GPA

Eosinophilic Granulomatosis with Polyangiitis (EGPA)

EGPA is characterized by asthma, peripheral and tissue eosinophilia, extravascular granuloma formation, and vasculitis of multiple organ systems.

Rare disease, with annual incidence of 1-3 per million. It can occur at any age (except in infants). The mean age of onset is 48 years, with a slight female predominance (6:5).

Pathology and Pathogenesis

The necrotizing vasculitis in EGPA involves small and medium vessels. It forms granulomatous reactions in tissues or vessel walls, associated with eosinophilic tissue infiltration. This can occur in almost any organ in the body.

The most common organs of involvement are the lung, skin, CVS, kidney, PNS, GI tract.

Likely due to aberrant immunologic phenomena given its strong association with asthma and clinicopathologic manifestations.

Clinical Manifestations

Respiratory Manifestations

These dominate the clinical picture: severe asthmatic attacks, pulmonary infiltrates. Upper airways can be affected: allergic rhinitis, sinusitis (61%) are often present in the early course of disease.

Neurologic Manifestations

Mononeuritis multiplex is the second most common manifestation (72%).

CV Disease

Occurs in 14% of patients and contributes to mortality.

Skin Lesions

Found in 51% of patients: purpura, cutaneous and subcutaneous nodules.

Renal Disease

Less common and generally less severe than in GPA or MPA.

Systemic Symptoms

Fever, malaise, anorexia, weight loss are common.

Laboratory Findings