08-19-2018, 07:20 PM
Granulomatosis with polyangiitis (previously known as Wegener's granulomatosis) is a small vessel granulomatous vasculitis that affects the:
• Upper respiratory tract (i.e. nose, sinuses)
• Lower respiratory tract (i.e. lung)
• Kidney
Granulomatosis with polyangiitis symptoms include necrotizing granulomas in kidney, upper and lower respiratory tract that can be seen as large nodular densities on chest X-ray.
Granulomatosis with polyangiitis in the upper respiratory tract produces symptoms that include chronic sinusitis, otitis media, and mastoiditis and lesions that include nasopharynx-saddle nose deformity and collapsed trachea.
Granulomatosis with polyangiitis in the lower respiratory tract produces symptoms that include hemoptysis, cough, and dyspnea and lesions that include cavitating nodular lesions.
Complications of Granulomatosis with polyangiitis are infarctions in the lungs and crescentic glomerulonephritis in the kidneys.
Patients with granulomatosis with polyangiitis are often positive for c-ANCA (PR3-ANCA) antibodies.
Treatment of Granulomatosis with polyangiitis involves corticosteroids and cyclophosphamide.
Microscopic polyangiitis is a small vessel necrotizing vasculitis that affects capillaries, arterioles, and venules.
Unlike polyarteritis nodosa, all lesions are at the same stage of inflammation and unlike in granulomatosis with polyangiitis (Wegener), granulomatous inflammation is absent.
Microscopic polyangiitis is MPO-ANCA (p-ANCA) positive in > 70% of patients.
The most common clinical manifestations of microscopic polyangiitis are:
• Constitutional symptoms (weight loss, fevers, malaise, joint and muscle aches)
• Kidney inflammation (necrotizing glomerulonephritis)
• Skin lesions (most commonly palpable purpura of the lower extremities)
• Peripheral nerve damage (mononeuritis multiplex: damage to two or more separate peripheral nerves)
• Lung involvement (pulmonary capillaritis leading to alveolar hemorrhage and hemoptysis)
Treatment of microscopic polyangiitis involves corticosteroids and cyclophosphamide.
Eosinophilic granulomatosis with polyangiitis (formerly known as Churg-Strauss syndrome) is a necrotizing small-vessel vasculitis that can be distinguished from polyarteritis nodosa by the presence of granulomas as well as the abundance of eosinophils.
Eosinophilic granulomatosis with polyangiitis is MPO-ANCA (p-ANCA) positive.
The American College of Rheumatology has 6 diagnostic criteria—presence of 4 of the following 6 is both sensitive (85%) and specific (>99%) for eosinophilic granulomatosis with polyangiitis:
1. Asthma (wheezing, expiratory rhonchi)
2. Paranasal sinusitis
3. Eosinophilia
4. Migratory pulmonary infiltrates on chest x-ray (“migratory” because these infiltrates may be transient and may appear to move to different locations on serial imaging examinations)
5. Extravascular accumulations of eosinophils—confirmed on tissue biopsy of skin or nasal polyp
6. Neuropathy (poly or mono) (usually peripheral neuropathy causing pain/anesthesia/parathesia in hands and feet)
(APE-MEN)
Immunoglobulin A vasculitis (formerly called Henoch-Schönlein purpura) is the most common systemic vasculitis in children. It typically affects the skin, joints, gastrointestinal tract, and kidneys
Biopsy of small vessels of the dermis and renal lesions in IgA vasculitis reveals typically deposits of:
• IgA
• IgG
• C3
IgA nephropathy is the renal manifestation of IgA vasculitis; it is characterized by recurrent hematuria along with diffuse mesangial proliferation and IgA deposition.
Upper respiratory tract infections (especially those involving Group A streptococcus) commonly precede IgA vasculitis.
Patients with immunoglobulin A vasculitis commonly present with:
• Palpable purpura on buttocks and/or legs
• Arthralgias
• Abdominal pain and GI bleeding
• Hematuria due to IgA nephropathy
Intussusception is the most common gastrointestinal complication of IgA vasculitis; edema and hemorrhage within the small bowel can act as a pathologic lead points in this setting.
Behçet syndrome is an immune-complex vasculitis that most commonly affects small- to medium-sized vessels. It is characterized by intermittent flares (1-4 week duration) that often manifest as:
• Recurrent oral aphthous ulcers (canker sores)
• Genital ulcers
• Uveitis (can manifest as hypopyon)
• Cutaneous lesions (e.g., erythema nodosum, acneiform lesions)
Behçet syndrome is most common in individuals of Turkish and eastern Mediterranean descent and is associated with HLA-B51.
Behçet syndrome is also known as the “silk road disease” given its greater prevalence in regions along the ancient silk road.
Herpes simplex virus (HSV) and parvovirus B19 can precipitate Behçet syndrome in predisposed individuals (e.g., those with HLA-B51).