Vaccine Induced Prothrombotic Immune Thrombocytopenia”, or VIPIT

 

Dr. Sanoop Kumar Sherin Sabu

M.D General Medicine Post Graduate Resident in GMKMCH Salem

17-04-2021

·         Various cases have been reported in Europe, Canada and India  about POST COVID VACCINE THROMBOTIC EVENTS, which accounts to less than 0.004% of events based on various publications.

·         Vaccine studied to show thrombotic events is - ChAdOx1 nCoV-19 vaccine ( In India it is known as  COVISHIELD)

·         This is not an official guideline / document but only a sincere effort  to help medical professionals for diagnosis and management, based on international guidelines available as of 17-04-2021

Vaccine induced prothrombotic immune thrombocytopenia, or VIPIT-

·         It is a condition of blood clots associated with low platelet counts, that occurs following receipt of the vaccine.

·         Presentations-

o    Thromboctopenia

o   Cerebral venous thrombosis- Most common site

o   pulmonary embolism

o   Coronary thrombosis

o   deep venous thrombosis

o   Peripheral arterial occlusion

o   Adrenal crisis

o   an ischemic stroke

o   portal vein thrombosis

• Petechiael hemorrhages 

·         Clinical features:- depend on the site of thrombotic events

o   persistent and severe headache

o   focal neurological symptoms

o    seizures, or blurred or double vision (suggesting CSVT or arterial stroke)

o    shortness of breath or chest pain (suggesting pulmonary embolism or acute coronary syndrome)

o    abdominal pain (suggesting portal vein thrombosis) or limb swelling, redness, pallor, or coldness (suggesting deep vein thrombosis or acute limb ischemia).

·         Time of onset- usually present 5 to 28 days after vaccination

·         Prevalence-  based on different publications the prevalence of reported cases so far is less than 0.004 %

·         Mechanism

o   Remain unclear. and it is unrelated to heparin therapy, though mechanism is similar to HIT ( Heparin Induced Thrombocytopenia) 

o   Studies shows it to be due to antibody induced platelet destruction.

o   anti-PF4 antibody   is found to be the culprit  

 

 ·         Investigations

·         Thrombocytopenia,

·         very high d-dimer level,

·          low or normal fibrinogen level

·         aPTT, PT-INR- elevated

·         MRA and MRV for suspected  Ischemic CVA/CVT

·         USG Doppler abdomen for Portal vein thrombosis

·         USG Doppler for DVT

·         ECG – features of CAD

 

·         Treatment of VIPIT  ( Based on UN Guidelines)

 

o    DO NOT give heparin

o    Avoid platelet transfusions

o    Consult a hematologist (in person, virtually, by phone)

o    Give intravenous immunoglobulin 1 g/kg daily for 2 days for severe or life-threatening clots, if available. Further IVIG may require balancing bleeding and thrombotic criss

o   Use first line anticoagulants: direct oral anti-Xa inhibitors (e.g. rivaroxaban, apixaban, edoxaban)

o   Treatment of VIPIT With Life Threatening Blood Clots In patients with confirmed VIPIT and severe or life-threatening blood clots (e.g., CSVT, splanchnic vein thrombosis), it is important to administer high dose intravenous immunoglobulin (IVIG) at 1g/kg of body weight daily for two days urgently, if available

 

References

1.      Pathologic Antibodies to Platelet Factor 4 after ChAdOx1 nCoV-19 Vaccination Marie Scully, M.D., Deepak Singh, B.Sc., Robert Lown, M.D., Anthony Poles, M.D., Thomas Solomon, M.D., Marcel Levi, M.D., David Goldblatt, M.D., Ph.D., Pavel Kotoucek, M.D., William Thomas, M.D., and William Lester, M.D..

2.      SIGNAL ASSESSMENT REPORT ON EMBOLIC AND THROMBOTIC EVENTS (SMQ) WITH COVID-19 VACCINE (CHADOX1-S [RECOMBINANT]) – COVID-19 VACCINE ASTRAZENECA (OTHER VIRAL VACCINES)

3.      INTERIM GUIDELINES: DIAGNOSIS AND MANAGEMENT OF VACCINE-INDUCED PROTHROMBOTIC IMMUNE THROMBOCYTOPENIA (VIPIT) FOLLOWING ASTRAZENECA COVID-19 VACCINATIONS 12 APRIL 2021.