Cerebral Venous Sinus Thrombosis (CVST): when headaches are more than just headaches

Cerebral Venous Sinus Thrombosis (CVST) is a rare but potentially dangerous condition in which a blood clot forms in the venous sinuses. These sinuses are responsible for draining blood from the brain to the heart. If this flow is interrupted, it can lead to increased intracranial pressure, cerebral oedema, or even cerebral hemorrhage.

What are the symptoms?

The most common symptom is the headache, but it has characteristics that are different from those of an ordinary headache:

• It either worsens progressively or is particularly severe from the outset.

• It often does not subside with common painkillers.

• It may also be accompanied by blurred vision, nausea, vomiting or double vision.

Other signs that should alert you are:

• Focal neurological symptoms, such as weakness or numbness in the face or limbs.

• Seizures, especially in people with no previous history of them.

• Disturbances in the level of consciousness.

• Swelling of the optic nerve during an ophthalmic examination.

Symptoms may develop gradually over a period of days, or they may have a more sudden onset. This variation often makes diagnosis difficult and requires clinicians to be highly cautious.

Who is most at risk?

CVST can occur at any age, but is more frequently seen in:

• In young women, especially in cases of:

o Contraceptive pill use.

o Pregnancy or postpartum.

• In people with thrombophilia (an inherited or acquired predisposition to thrombosis).

• Following a sinus or ear infection that spreads intracranially.

• In cases of malignancy, dehydration or severe systemic inflammation.

• Less commonly, it may be associated with immunological conditions such as lupus erythematosus or antiphospholipid syndrome.

In recent years, the association of CVST with certain types of COVID-19 vaccines which use adenovirus vectors, has been discussed in very rare cases, mainly affecting women under 60.

How is the diagnosis made?

As mentioned, the clinical picture is not always typical. For this reason, specific imaging is required when suspicion arises. A simple CT scan of the brain may appear normal. The diagnosis is usually made by:

• Magnetic Resonance Brain Venography (MRV).

• Computed Tomography Venography (CTV).

These tests image the venous sinuses and reveal the presence of a clot.

What is the treatment?

The main approach is anticoagulation, even when there is concomitant bleeding in the brain. The objective is to:

• Stop the clot from expanding.

• Restore normal venous flow.

• Reduce the risk of complications.

Treatment typically begins with heparin, either injected or administered subcutaneously, followed by long-term oral anticoagulation therapy lasting 3–12 months, depending on the underlying cause.

In extremely severe cases where there is life-threatening pressure on the brain, neurosurgery or intravascular thrombolysis may be necessary, but these cases are rare.

What is the prognosis?

With an early diagnosis and proper treatment, the prognosis for CVST is quite good: over 80–85% of patients make a full recovery. However, if diagnosis is delayed or if thrombosis is extensive, permanent neurological damage or even death can occur.

Recurrence is relatively rare, but lifelong anticoagulation may be required in cases of thrombophilia.

What should you watch out for?

• Persistent or unusual headaches, especially when accompanied by other neurological symptoms, should be evaluated immediately.

• CVST is potentially reversible if diagnosed early.

• Early imaging and proper treatment are key to full recovery.

If you have any concerns or experience symptoms that worry you, contacting a qualified neurologist could make the difference.