Inclusion Criteria [Both of]:

1. Received AstraZeneca (AZ) COVID 19 vaccination within 42 days (typically 5-42 days from immunisation)
2. New Onset thrombocytopenia (PLTs <150×109/L) – with or without Thrombosis
   • 5% of cases have had a “Normal” Platelet count at presentation
     • High index of suspicion repeat bloods next day
     • ‘High index of suspicion’ in this context is day 5- 28 post AZ vaccine with new onset headache or abdominal pain which is atypical and severe in nature.

Initial Investigations:

• FBC– specifically to confirm thrombocytopenia <150x 109/L
• Coagulation screen and D Dimers
• Blood film to confirm true thrombocytopenia and identify alternative causes

PROBABLE CASE: (ALL 3 criteria)

1. Received AZ COVID 19 vaccination within 42 days
2. New Onset thrombocytopenia (PLTs <150×109/L)
3. D Dimers > 2000 mcg/L

URGENT Scan to confirm the suspected clot.

[If patient doesn’t fit “PROBABLE CASE” proceed to usual treatment]

Condition specific advice:

Central clot:

• inc. Cerebral Venous Sinus Thrombosis (CVST), Pulmonary Embolis (PE), Splenic, Proximal DVT
• Discuss with Haematologist
• Admit Medicine

Suspected DVT (scan unavailable):

• Treat with Rivaroxaban (Do Not use Tinzaparin/LMWH)
• Request Ultrasound
• Return AAU Next Day
• Safety-net Advice

Confirmed Distal DVT (Not above inguinal ligament)

• Platelets  <100×109/L – Discus with Haematology
• Platelets ≥100×109/L – Treat as normal

Thrombocytopenia only

• Platelets  <100×109/L – Discus with Haematology
• Platelets ≥100×109/L – Treat as normal

Treatment (will be directed by Haematology & Specialist teams):

Avoid:

• Heparin Based anticoagulants
• Antiplatelets
• Platelet Transfusion

May Require:

• IV immunoglobulin
• Steroid
• Anticoagulation with: DOAC, Fondaparinux, Argatroban

Further reading

• MHRA Data
• British Society of Haematology
• RCEM