Ch. 34 Polyarteritis Nodosa Flashcards
Definition of classical PAN
Necrotizing inflammation of medium- or small-sized arteries, without vasculitis in arterioles, capillaries, or venules
Definition of microscopic polyangiitis (MPA)
Necrotizing vasculitis with few or no immune deposits affecting small vessels
ANCA-associated vasculitis which is predominantly a renal disease and usually presents in childhood as RPGN
MPA
Classification criteria for childhood PAN
Mandatory histopath or angio + 1 out of 5:
- Skin involvement (livedo, nodules, or infarcts)
- Myalgia or muscle tenderness
- Htn
- Peripheral neuropathy
- Renal involvement
MC clinical manifestations of PAN
Cutaneous, fever, and myalgia
T/F ANCA and ANA are typically positive in PAN
F, negative
Most valuable imaging procedure for the diagnosis of PAN
Catheter digital subtraction angiography
Common finding in DSA indicative of PAN
Aneurysms
Most reliable nonaneurysmal signs on imaging that supports PAN
Perfusion defects
Collateral arteries
Delayed emptying of small renal arteries
GOLD STANDARD in the diagnosis of PAN
Conventional angiography
T/F Tissue biopsy should be performed in patient with suspected PAN
T
Characteristic histopath changes in PAN
Fibrinoid necrosis of walls of medium or small arteries with marked inflammatory response within or surrounding a vessel wall
T/F Absence of supportive histopathological findings excludes a diagnosis of PAN
F, disease is patchy in nature
T/F Glomerulonephritis is common in PAN
F, true GN is uncommon, and when present, suggests polyangiitis overlap
Treatment for mild PAN and isolated cutaneous disease
Monotherapy with oral glucocorticoid (Prednisone 1mkd) for 4 weeks. If with substantial improvement, taper slowly until 20mg/day (adult 0.3mkd if 60kg) is reached by ~3-4 months. Then decrease by 2.5mg every 14 days. Overall course of 6-8 months until d/c. If with inadequate response, (no response in 3 months or cannot be tapered to at least 10mg/day without relapse) add AZA (2mkd) or MTX (20-25mg weekly) to be given for at least 1 year following attainment of clinical remission.
Induction for moderate to severe PAN
Glucocorticoid (Pred 1mkd with or w/o IV MPPT depending on severity) + CYC (0,2,4,then every 3 weeks @ 15mg/kg OR 600mg/m2 every 2 weeks x 3 doses then every 4 weeks for at least 4 months until remission but no greater than 6 months.
Maintenance for moderate to severe PAN
12-36 months. MMF, AZA, MTX. May be withdrawn slowly over at least 6 months if patient has been on remission for at least 12 months on maintenance therapy.
T/F PAN appears to be a condition in which permanent remission can be achieved
T
Important aspects of management that should be considered in patients with PAN
- Antiplatelet
- PCP prohpylaxis
- Osteoporosis prophylaxis
- Gastric protection
- GAS prophylaxis when implicated, added to induction therapy for at least 12 months
Recommended approach to Hep B associated PAN
Plasma exchange +
Antiviral treatment +
Corticosteroids to control acute manifestations
THEN stop corticosteroids to enhance immunologic clearance of virus
Characteristics of skin lesions in cutaneous PAN
Nodular, painful, nonpurpuric, with or without livedo racemosa, predominantly in the LE
Systemic involvement that may be seen in cPAN
Myalgia, arthralgia, nonerosive arthritis
Differentiates cPAN from PAN in terms of skin features
Infarcts are not present in cutaneous disease
Differentiates PAN from cPAN in terms of clinical course
cPAN is characterized by periodic exacerbations and remissions
