Sinus thrombosis, CVST  

A thrombosis means that a blood clot forms in a blood vessel and becomes stuck in a vein or artery. When a thrombosis occurs in the cerebral veins, it is called a sinus thrombosis.
Sinus is the name for a vein in the brain that is located on the surface of the brain, under the skull. These sinuses are formed by the two layers of the dura mater.
In several places the inner layer loosens and bends inward. This creates folds (dural folds) and spaces (dural venous sinuses) between the inner and outer layers.
The sinuses open at a junction of veins. These are called confluens sinuum, where the veins merge into multiple sinuses.

The deoxygenated blood flows further and ends in a deep vein in the neck, which drains blood from the neck, face and brain (the internal jugular vein). This way the blood flows back to the heart.

 

In the case of a cerebral sinus thrombosis, one or more large veins (sinuses) in the brain are blocked by a clot (a blood clot or multiple blood clots).

Synonyms: 'cerebral sinus thrombosis or cerebral/central venous thrombosis CVT or cerebral venous sinus thrombosis CVST'.

 

 

Brain functions may fail and, in the worst case, brain tissue may die.
The person may develop a severe headache, a paralyzed arm or leg, a crooked mouth, difficulty speaking, poor vision or even no vision and/or an epileptic attack, and sometimes a person with a sinus thrombosis may fall into a coma.
There may be increased CSF pressure. This can be measured with a lumbar puncture. Cerebrospinal fluid (cerebrospinal fluid) is produced in the choroid plexus (in the brain chambers, ventricles) and ultimately reabsorbed in the venous sinus of the brain. Obstruction prevents the CSF from flowing through and increases CSF pressure. Expansion of the ventricles (hydrocephalus) can also occur. If the CSF pressure is too high for a long time, it can threaten vision.
Although the symptoms are similar to a stroke, the treatment is different. First, an infusion of blood-thinning medications is started, after which other anticoagulants are later given later on.

 

A common cause is impaired blood clotting due to pregnancy, childbirth or pill use, which is why sinus thrombosis is common in young women. We have a separate page for complications in pregnancy.
The average age at which people develop a sinus thrombosis is lower than that of a stroke from the cerebral arteries (arterial cerebrovascular disease).

It usually concerns young adults and children. CVST can also occur in infants. CVST is more common in women than in men.

 

Causes and risk factors

• impaired blood clotting, the blood clots faster than normal
  • due to family predisposition (hereditary): protein S deficiency, protein C deficiency, antithrombin deficiency, Factor V Leiden mutation, prothrombin G20210A gene variant.
  • acquired coagulation disorders: Antiphospholipid syndrome, hyperhomocysteinemia, hematological disorders (myeloproliferative disorders, thrombocythemia), nephrotic syndrome
• risk factors for thrombosis; use of the contraceptive pill (particularly "the third generation pill" in combination with obesity. BMI over 30),
  pregnancy (particularly the last three months or around the time of delivery).
  
• Since 2020, sinus thrombosis has been associated with vaccination (after Janssen and Astrazeneca vaccines) against the coronavirus as a possible side effect. (COVID-19) Questions about the corona vaccines, anticoagulation medication and thrombosis (thrombosestichting.nl)
  
• purulent inflammations in the head such as sinus infections, meningitis or middle ear infection. This is called an infectious sinus thrombosis. This must be cleaned by surgery and treated with antibiotics.
  
• inflammation of the small blood vessels.
  
• systemic inflammatory conditions (systemic lupus erythematosus / SLE, sarcoidosis, vasculitis, behcet)
  
• cancer
  
• head trauma or neurosurgical procedures or lumbar puncture

 

Complaints may include

• acute and severe headache (headache may also be absent!)
• failure symptoms, like with a TIA or a stroke/CVA (difficulty speaking, loss of half of the face, double vision, balance disorders, loss of consciousness, symptoms of paralysis of the arm or leg)
• cramp
• vomiting
• fever
• problems with vision, sometimes a bulging eye, sometimes the eyes are directed towards the nose, sometimes there is swelling of the eye conjunctiva
• facial pain
• epileptic seizures (in 40%)
• sometimes edema of the forehead
• increased CSF pressure, cerebral pressure/increased cranial pressure
• sometimes confusion
• loss of consciousness, sometimes coma

 

Diagnosis

• head scan:
  • CT venography
  • MRI
  • MR venography
  • angiography

 

Treatment

In the acute phase, not only must the cause be addressed, such as in the case of an infection with antibiotics, or in the case of a blood vessel blockage with anticoagulation medication, but also the increased cerebral pressure or disturbance of consciousness or coma must be treated.

Patients should be monitored intensively, preferably on a stroke unit in a high care or intensive care unit.

 

Residual symptoms

Some people recover and become 'almost their old self' again, others are left with symptoms such as concentration problems, headaches, memory problems, mood problems and fatigue.

There are also people who suffer from severe disabling consequences, for example epilepsy or half-sided paralysis. People can also die from sinus thrombosis.