Eosinophilic Granulomatosis

Question 1

What is Eosinophilic granulomatosis with polyangiitis (EGPA)?

Answer 1

• one of the anti-neutrophil cytoplasmic antibody (ANCA) associated vasculitides (AAV)
• characterised by allergic rhinitis, asthma, and prominent peripheral blood eosinophilia
• small to medium vessel vasculitis.

Question 2

What are the ANCA-associated vasculitis?

Answer 2

• Microscopic polyangiitis (MPA)
• Granulomatosis with polyangiitis (GPA)
• Eosinophilic granulomatosis with polyangiitis (EGPA)

Question 3

What is EGPA previously known as?

Answer 3

Churg-Strauss syndrome

Question 4

What are the causes of EGPA?

Answer 4

• HLA-DRB1
• HLA-DRB4
• Medications (asthma related)
  
  • montelukast
  • Inhaled corticosteroids
  • Omalizumab

Question 5

What are the disease phases of EGPA?

Answer 5

1. Prodromal phase:
   
   • ​​asthma and allergic rhinitis
2. Eosinophilic phase:
   
   • eosinophils infiltrate a variety of tissue without overt vasculitis. May see marked eosinophilia on full blood count.
3. Vasculitic phase:
   
   • multi-system involvement with granulomatous inflammation

Question 6

What are the clinical features of EGPA?

*affects multiple systems

Answer 6

ENT

• Sinusitis
• Allergic rhinitis
• Nasal polyps
• Otitis media

Pulmomary

• Cough
• Dyspnoea
• Wheeze
• Haemoptysis

Cardiac

• heart failure
• pericarditis +/- pericardial effusion
• arrhythmias

Kidney

• necrotising glomerulonephritis

Question 7

What is the ACR diagnostic criteria for EGPA?

Answer 7

≥4 needed to be present

• Asthma
• > 10% eosinophils on differential count
• Peripheral neuropathy (mono-/poly-/mononeuritis multiplex)
• Migratory or transient pulmonary opacities (on imaging)
• Paranasal sinus abnormality
• Confirmation of extravascular eosinophil infiltration on biopsy

Question 8

What are the key findings of EGPA?

Answer 8

• raised peripheral eosinophil count
• difficult to control asthma

Question 9

What Ix would you order for EGPA?

Answer 9

Bedside

• Urinalysis
• Red cell casts

Bloods

• FBC + film (to assess for blasts or abnormal eosinophils)
• ESR/CRP
• U&E
• LFT
• Bone profile
• Troponin and NT-proBNP: if cardiac involvement suspected
• Coagulation

Vasculitis screen

• pANCA: positive in around 50%
  
  • cANCA (+) in GPA
• ANA
• Rheumatoid factor
• Anti-GBM

Question 10

What Imaging would you order for EGPA?

Answer 10

• Chest x-ray: look for infiltrates, consolidation, effusions
• CT chest: better at assessing degree of pulmonary involvement compared to chest x-ray
• CT sinuses: may be used to look for sinus involvement
• Echocardiography and cardiac MRI

Question 11

What special test would you order for EGPA?

Answer 11

• Pulmonary function tests
• Biopsy of affected tissue (usually nasal, skin or kidneys)
• Nasoendoscopy
• Bronchoscopy +/- bronchoalveolar lavage

Question 12

How would you mx EGPA?

Answer 12

Induction therapy

• prednisolone at 0.5-1.0 mg/kg/day) - first line
• Methylprednisolone 1g daily for three days
• Cyclophosphamide

Maintenance therapy

• azathioprine
• methotrexate

Question 13

What is a common SE of cyclophosphamide and what drug should be administered together?

Answer 13

• haemorrhagic cystitis
• ]mesna

Question 14

What are the cx of EGPA?

Answer 14

• Cardiac failure and/or myocardial infarction
• Cerebral haemorrhage
• Severe acute kidney injury
• Gastrointestinal bleeding
• Severe exacerbation of asthma