Type III hypersensitivity

Question 1

What is Type III Hypersensitivity

Answer 1

IgG/IgM immune complex-mediated tissue damage

Question 2

Mixed Essential Cryoglobulinaemia pathophysiology

Answer 2

IgG/IgM immune complexes in blood +/- hep C antigens → joint pain, splenomegaly, nerve and kidney involvement
Associated with Hep C

Question 3

Mixed Essential Cryoglobulinaemia Mx

Answer 3

Anti-inflammatory drugs e.g.g corticosteroids
Plasmapharesis (severe)

Question 4

What is serum sickness?

Answer 4

Type III reaction to proteins in injected serum

Question 5

What is polyarteritis nodosa?

Answer 5

Type III reaction against Hep B, C virus antigens → systemic symptoms, arthralgia, skin symptoms, nerve, heart and kidney involvement
Ix: ESR, CRP, WCC raised
imaging - Rosary sign
Mx: Pred and Cyclo

Question 6

What is SLE?

Answer 6

Type III HS reaction
immune complexes against dsDNA, histone and RNP
Sx: SOAP BRAIN MD
Ix: increased ESR
anti-dsDNA +ve
Mx: analgesia, steroids, immunosuppression