AZ vaccination reaction

Question 1

A 32 year old female received the Astra Zeneca COVID-19 vaccination 7 days ago, and presents with a 4 day history of abdominal pain, headache, vomiting, and hypertension. How would you manage her?

Answer 1

Impression
Given recent AZ vaccination, the most important life-threatening reactionI could like to exclude is vaccine-induced thrombotic thrombocytopenia central venous sinus thrombosis or splanchnic venous thrombosis potentially causing mesenteric ischaemia.

VITT usually presents 7-14 days post-AZ administration, can also result in DIC.

DDX - otherwise non-specific symptomatology
- infective: gastro, other viral/bacterial infection, COVID
- inflammatory: cholecystitis, GORD, autoimmune
- Neuro: meningitis, SOL, ICH, IIH

Question 2

AZ vaccine reaction - History

Answer 2

History
- sx: onset, temporal relationship to vaccine. 1st or second dose? (1st dose much more likely to cause VITT).
- PC: abdo pain (SOCRATES), headache
- REDS: seizures, haematochezia, visual changes,
- DDX: travel history, sick contacts,
- PMHx: clotting disorders, medications, allergies
- Risks: female, younger age
- SNAP

Question 3

AZ vaccine reaction - Examination

Answer 3

Examination
- General appearance + vitals
- Abdominal examination: focal tenderness, shifting dullness, GIT bleeding, signs of thrombocytopenia with petechiae, etc
- Neuro: signs of raised ICP (papilloedema, pupils, cushings response), other focal neurology
- Systems review

Question 4

AZ vaccine reaction - Investigations

Answer 4

Investigations
- Bedside: ECG for ?PE
- Bloods: Coags, ß-HCG (exclude pregnancy), FBC (platelet count), UEC, VBG (for lactate in ?ischaemic gut), PF4 antibody levels (not helpful acutely but highly sensitive and confirmatory), D-Dimer (Expect to be high)
- Imaging: CT Brain +/- CT Venogram, Abdo CT +/- angio for ischaemic gut

Question 5

AZ vaccine reaction - Management

Answer 5

Management
- consult for senior advice, and haematology input

Definitive for VITTs
- anticoagulation (NOT heparin/Clexane given cross-over with HITT - therefore NOACS), continue into medium term
- IVIG + corticosteroids
- consider platelet transfusion if bleeding (last-line, reserved for critical bleeding)

Supportive
- analgesia
- IV fluids
- monitoring of platelet count
- TGA adverse events reporting
- appropriate follow up