Understanding Cerebral Venous Sinus Thrombosis with Thrombocytopenia

CVST with thrombocytopenia is a combination of CVST and a low platelet account. It’s been identified as a side effect of some COVID-19 vaccines and the medication heparin.

CVST

CVST is a blood clot in the major veins of your brain. It was estimated to have an incidence rate of 3 per 100,000 in the United States using data from 2018 to 2019.

CVST is often considered a type of stroke. By far, the most common symptom is headache. People often describe their headache as “the worst headache of my life.”

Other symptoms depend on where the blood clot is located and how big it is. Symptoms may include:

• seizure
• nausea and vomiting
• changes in mental status
• impaired movement
• trouble speaking
• vision problems
• loss of consciousness

Risk factors for CVST include:

• obesity
• oral contraceptive use
• infections such as meningitis or brain abscess
• head trauma
• COVID-19
• conditions that increase blood clotting
• pregnancy

Thrombocytopenia

Thrombocytopenia is a condition characterized by a platelet count that’s lower than normal. It impairs your blood’s ability to clot and can cause symptoms such as:

• prolonged and heavy bleeding
• small red spots under the skin called petechiae
• easy bruising
• frequent nosebleeds or bleeding from gums
• blood in your urine or stool
• heavy menstruation

Thrombocytopenia has many potential causes, including:

• pregnancy
• infections
• conditions that cause your blood to clot such as thrombotic thrombocytopenic purpura
• cancer
• autoimmune disease
• aplastic anemia, a rare blood disorder
• enlarged spleen
• some types of surgery, such as bypass surgery
• exposure to chemicals, such as some pesticides and benzene
• high alcohol consumption
• some medications

CVST and thrombocytopenia together

In a 2022 study, researchers from the Centers for Disease Control and Prevention (CDC) found the following conditions were more common among people hospitalized with CVST with or without thrombocytopenia:

• meningitis
• encephalitis
• head and neck infections
• cancer
• head injuries
• connective tissue disorders
• bleeding disorders
• history of blood clots

Blood clots with thrombocytopenia have also been reported as a side effect of the liver medication heparin.

Additionally, CVST with thrombocytopenia may be a very rare side effect of adenoviral vector COVID-19 vaccines. It’s thought that the underlying cause is an immune reaction that leads to platelet activation.

CVST and thrombocytopenia rarely occur together from other causes. In a 2017 case study, researchers reported a case of CVST that developed in a person with immune thrombocytopenic purpura who received treatment with high dose intravenous (IV) immunoglobin.

Researchers have found evidence that CVST with thrombocytopenia is a very rare side effect of adenoviral vector vaccines. These vaccines include the AstraZeneca vaccine and the Johnson & Johnson/Janssen vaccine.

Vaccine-induced CVST with thrombocytopenia may develop 4 to 42 days after vaccination.

In a 2023 study, researchers found two cases of CVST with thrombocytopenia among 200,397 people vaccinated with the AstraZeneca vaccine. They found no cases of CVST with thrombocytopenia among more than 780,000 people who received the first dose of Moderna or Pfizer-BioNTech.

CVST with thrombocytopenia hasn’t been identified as a side effect of the Pfizer or Moderna vaccines. The World Health Organization (WHO) identified 756 cases of CVST without thrombocytopenia among 1.2 million administrations of Pfizer or Moderna.

Risk of CVST from COVID-19 and COVID-19 vaccines

CVST is much more common among people with COVID-19 than those who receive COVID-19 vaccines.

In one 2021 study, researchers found the rates of CVST were 88 people per 100,000 during the pandemic and 30 to 40 people per 100,000 before the pandemic.

The risk of developing CVST after COVID-19 vaccination is extremely low, and vaccines can help prevent serious cases of COVID-19.

Doctors can diagnose thrombocytopenia with a blood test that measures the number of platelets in a sample of your blood. They can also measure levels of other substances that suggest a blood clotting condition such as fibrinogen or D-dimer.

Doctors can diagnose CVST with imaging. The most common types of imaging are:

• noncontrast CT scan
• MRI scan
• magnetic resonance venography
• computed tomogram venography

Initial treatment for confirmed CVST with thrombocytopenia usually includes immunoglobin delivered intravenously and a nonheparin anticoagulation medication.

Other treatments include:

• plasma exchange for people with severe disease
• treatments for specific side effects such as:
  • acetazolamide or shunts to reduce intracranial pressure
  • antiepileptic medications for seizures
  • treatments to stop bleeding

Prompt medical attention is needed to treat CVST with thrombocytopenia to minimize the risk of developing severe complications. According to a CDC study, about 1 in 10 people with CVST with thrombocytopenia died in the hospital.

In a 2022 review of 49 people who developed CVST with thrombocytopenia, researchers found that:

• 29.6% had a good recovery.
• 25% developed moderate disability.
• 13.6% developed severe disability or vegetative state.
• 31.8% died.

CVST with thrombocytopenia is characterized by a blood clot in the brain and a platelet count that’s lower than normal. Research suggests it’s a rare side effect of adenoviral vector COVID-19 vaccines and the medication heparin.

Prompt treatment is needed for CVST with thrombocytopenia. It’s vital that you call 911 or local emergency services if you or somebody else develops potential symptoms such as headaches, blurry vision, or seizures with no known cause.