Polyangiitis – MPA, GPA, EGPA
OVERVIEW
- similar but different diseases
- positive Antineutrophil cytopasmic antibiodies (ANCA)
- renal histology (focal necrotizing, pauci-immune glomerulonephritis)
MPA (Microscopic Polyangiitis)
- no granulomas
- MPO-ANCA (myeloperoxidase)
- lower rates of upper respiratory tract involvement
- lower rate of relapse after immunosuppression
GPA (Granulomatosis With Polyangiitis) [archaic: Wegener’s granulmatosis]
- granulomas
- PR3-ANCA
- involvement of respiratory tract
- more recurrence
EGPA (Eosinophilic granulomatosis with polyangiitis) [archaic: Churg–Strauss syndrome]
- eosinophil-rich, necrotizing granulomatous inflammation
- necrotizing vasculitis predominantly affecting small to medium vessels
- involvement of respiratory tract
HISTORY
- rhinorrhea, bloody nasal discharge, oral/nasal ulcers, sinus pain
- haemoptysis
- pleuritic chest pain
- haematuria
- stridor (subglottic stenosis)
- myalgias
- arthalgia
- conjunctivitis
- corneal ulceration
- skin lesions
- at high risk of DVT
EXAMINATION
- pleural effusions
- pulmonary infiltrates
- skin vasculitis lesions
INVESTIGATIONS
- leucocytosis
- thrombocytosis
- elevated ESR and CRP
- normochromic, normocytic anaemia
Antineutrophil cytopasmic antibiodies (ANCA)
- PR3-ANCA = GPA
- MPO-ANCA (myeloperoxidase) = MPA
Tissue biopsy
- chronic inflammation
- granulomas
- renal biopsy: segmental necrotizing glomerulonephritis, crescents
Urine
- casts
- proteinuria
CXR
- pulmonary infiltrates
- nodules
- alveolar or pleural opacities
- hilar adenopathy
MANAGEMENT
Induction
- proportional to severity (localised, early systemic, generalized, severe, refractory)
- cyclophosphamide 2mg/kg/day
- methylprednisolone 15mg/kg/day for 3 days -> prednisone 1mg/kg PO OD
- PCP prophylaxis (co-trimoxazole)
Alternatives
- methotrexate
- plasma exchange
Critical Care
Compendium
Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also a Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.
After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.
He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE. He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.
His one great achievement is being the father of three amazing children.
On Twitter, he is @precordialthump.
| INTENSIVE | RAGE | Resuscitology | SMACC