Systemic Vasculitis
Rheumatology · Systemic Vasculitis 🎯 Practice these cards
In suspected GCA, start ____ immediately to prevent blindness; temporal artery biopsy stays positive for up to ____ weeks after steroids.
Suspected giant cell arteritis is a medical emergency because ischemic optic neuropathy causes irreversible blindness. Start high-dose prednisone (1 mg/kg/day, up to 80 mg) IMMEDIATELY; use IV pulse methylprednisolone for acute visual loss. Temporal artery biopsy remains diagnostically positive for up to 4 weeks after glucocorticoids, so confirm within 2 weeks without delaying therapy.
Because GCA has ____ lesions, biopsy must sample >____ cm of temporal artery; a negative biopsy with high suspicion should be managed by ____.
GCA inflammation is segmental (skip lesions), so false-negative biopsies are common. Obtain >1 cm of temporal artery with serial sectioning; unilateral biopsy is recommended. Continue treatment despite a negative biopsy if clinical suspicion is high. Ultrasound may show a non-compressible 'halo' sign.
GCA and Takayasu share similar ____; the key distinguishing feature is patient ____ , with a boundary near ____ years.
GCA and Takayasu arteritis are both large-vessel granulomatous vasculitides with similar histology, separated mainly by age: GCA occurs almost exclusively in patients >50 (peak 70-80), while Takayasu predominantly affects younger women (adolescents/young adults). Takayasu favors the aorta and its primary branches and causes stenotic ('pulseless') and aneurysmal lesions.
PMR responds dramatically to ____ -dose prednisone (12.5-20 mg/day); lack of a rapid response should prompt reconsideration of the ____.
PMR causes symmetric pain and stiffness of the shoulder and hip girdles (worst in the morning) with normal muscle enzymes. It responds dramatically to moderate-dose prednisone (12.5-20 mg/day); failure to improve promptly should prompt reconsideration of the diagnosis. 10-20% of isolated PMR patients have or develop concomitant GCA.
PAN characteristically spares the ____ and does NOT cause ____; its renal involvement is ____ rather than glomerular.
PAN is a medium-vessel necrotizing vasculitis affecting skin, peripheral nerves (mononeuritis multiplex), GI tract, and kidneys. Renal disease is renovascular (microaneurysms -> hypertension), NOT glomerular. PAN characteristically spares the lungs and does not cause glomerulonephritis; ANCA are rarely positive. Gold-standard diagnosis: medium-vessel biopsy (panmural necrotizing inflammation) or angiographic microaneurysms.
c-ANCA targets ____ and is linked to ____; p-ANCA targets ____ and is linked to MPA and EGPA.
c-ANCA (cytoplasmic, anti-proteinase-3/PR3) is associated with GPA (>80-90% of active cases). p-ANCA (perinuclear, anti-myeloperoxidase/MPO) is associated with MPA and EGPA. ANCA are neither perfectly sensitive nor specific: a negative ANCA does not exclude AAV, and a p-ANCA pattern without anti-MPO specificity occurs in non-vasculitic conditions.
GPA induction uses glucocorticoids plus ____ (preferred) or ____; maintenance is led by ____ , the agent best at preventing relapse.
GPA induction for severe disease: high-dose glucocorticoids plus rituximab (preferred) or cyclophosphamide. Maintenance: rituximab (best at preventing relapse), methotrexate, or azathioprine, usually >=2 years. Glucocorticoids alone are insufficient. With modern therapy, mortality has fallen from ~90% to ~10%, but relapse remains common (>50%).
Unlike GPA, MPA spares the ____ and lacks ____ on biopsy; its ANCA are usually anti-____.
MPA affects the lungs and kidneys like GPA but SPARES the upper airways and is NOT granulomatous on biopsy; the absence of granulomas distinguishes MPA from GPA. ANCA are less prevalent (50-75%) and usually anti-MPO/p-ANCA. Diagnosis: pauci-immune necrotizing small-vessel vasculitis or crescentic glomerulonephritis on biopsy. Treatment is the same as GPA.
EGPA is defined by the triad of ____ , ____ , and vasculitis; its leading cause of death is ____ disease, so all new cases need echocardiography.
EGPA (Churg-Strauss) evolves through a prodromal asthma/atopy phase, an eosinophilic phase (peripheral and tissue eosinophilia, migratory infiltrates), and a vasculitic phase (mononeuritis multiplex 70%, kidney 25%, skin 60%). ANCA are positive in only 40-60%. Cardiac disease (myocarditis, coronary vasculitis) is the leading cause of death (~39%); echocardiography is recommended in all new cases.
About two thirds of mixed cryoglobulinemia is related to ____ ; the classic complement finding is a low ____ ; the blood sample must be kept at ____ C until clotting.
Mixed cryoglobulinemia (types II/III) accounts for 75-90% of cases; about two thirds are hepatitis C-related. Features: palpable purpura (~90%), arthralgia without arthritis, neuropathy, and membranoproliferative GN. Clues: very low C4/CH50 and positive RF. The sample must be kept at 37 C until clotting to avoid a false negative. First-line therapy is antiviral treatment of HCV; severe vasculitis gets glucocorticoids plus rituximab.
IgA vasculitis is confirmed by heavy ____ deposition on immunofluorescence; unlike children, adults are at risk for persistent ____ .
IgA vasculitis (Henoch-Schonlein purpura), common in children (peak 4-7 years), presents with palpable purpura in dependent areas, abdominal pain/GI bleeding (50%), arthritis/arthralgia (90%), and glomerulonephritis, usually after an upper respiratory infection. Diagnosis: heavy IgA and complement deposition on skin biopsy immunofluorescence. Childhood disease is usually self-limited; adults risk persistent nephropathy.
Hypersensitivity vasculitis is confined to the ____ , appears ____ to ____ days after antigen exposure, and shows leukocytoclastic vasculitis without heavy ____ deposits.
Hypersensitivity (cutaneous) vasculitis is an immune complex small-vessel vasculitis confined to the skin, triggered by a drug or infection (antigen unknown in ~50%). Palpable purpura appears in crops 7-10 days after exposure and resolves within weeks of trigger removal; internal organs are spared. Biopsy shows leukocytoclastic vasculitis WITHOUT heavy IgA deposits. Management: remove the trigger; cyclophosphamide should almost never be used.
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