It’s causing cerebral venous sinus thrombosis. That is deadly.

Fun fact; Hillary Clinton suffers from it.

U.S. Secretary of State Hillary Clinton was hospitalized on December 30, 2012, for anticoagulation treatment of venous thrombosis of the right transverse sinus, which is located at the base of the brain. Clinton's thrombotic episode was discovered on an MRI scan done for follow-up of a cerebral concussion she had suffered 2.5 weeks previously, when she fell while suffering from gastroenteritis.[36]

Cerebral venous sinus thrombosis (CVST), cerebral venous and sinus thrombosis or cerebral venous thrombosis (CVT), is the presence of a blood clot in the dural venous sinuses (which drain blood from the brain), the cerebral veins, or both. Symptoms may include severe headache, visual symptoms, any of the symptoms of stroke such as weakness of the face and limbs on one side of the body, and seizures.

It’s causing cerebral venous sinus thrombosis. That is deadly.