Cerebral Venous Sinus Thrombosis

One of the most frequent presentations in the ED is a patient complaining of headache. There is a wide range of differentials, such as mental illnesses to life threatening causes. Cavernous sinus thrombosis is amongst them, thus making it one of the main causes that need to be ruled in or out when a patient first presents to the ED with complaints of headache.

The most common presentation you may encounter or a presentation frequently asked in exams would be of a young female on oral contraceptive pills who presents with a headache and limb weakness. Although the list of differentials is long, cerebral venous thrombosis should definitely be kept amongst the top 3, as early diagnosis is key.

What is Cerebral Venous Thrombosis (CVT)?

CVT is the formation of a clot in the cerebral veins and the dural sinuses. The dural sinuses consist of the superior sagittal sinus, straight sinus, and transverse sinus. These are the sites commonly affected by clot formation. Rarely, it may present in cortical veins and jugular veins.

It is considered a type of stroke and is divided into three types: acute, subacute, and chronic.

Epidemiology and Risk Factors

Young patients between the ages of 20-50 years are most commonly affected, especially women of the age group are affected more compared to men.

People with factors contributing to Virchow’s Triad (stasis, endothelial injury, and hypercoagulability) are at a higher risk of getting affected. Other factors include – genetic disorders such as thrombophilia, APS – antiphospholipid syndrome, autoimmune disorders, malignancies, pregnant women, recent surgery, use of oral contraceptive pills, infections (most commonly sinusitis and meningitis), patients who recently underwent lumbar puncture, and catheterization of the jugular vein.

Anatomy

Cerebral veins are compromised of a deep and superficial system. The veins do not have valves. There are several connections between the veins of both systems and the sinuses.

Venous blood from cerebral veins drains into the major dural sinuses and the internal jugular vein. The superficial system mainly drains into the superior sagittal sinus and the lateral sinus.

Pathophysiology

How does it happen? The exact mechanism is unknown; however several studies propose the following theory: Thrombus formation in veins causes obstruction as the blood pools and raises pressure within the blood vessels and decreases CSF drainage. This CSF collection gives rise to intracranial hypertension and hydrocephalus, leading to the most common symptom patients present with – headache and stroke-like symptoms. Almost half of the cases have hemorrhagic transformation prior to treatment.

History and Physical Examination

The presentation is non-specific and may mimic other illnesses, making it one of the hardest to diagnose.

The history and physical examination findings depend on the extent of the thrombosis.

Some of the most common complaints in patients with CVT include-

  • Headache is the most common presentation – in the case of a patient complaining of sudden onset headache typical of subarachnoid hemorrhage, CVT should always be kept in mind as an uncommon yet possible cause.
  • Nausea, vomiting may also be present.
  • Seizures
  • Papilledema
  • Focal neurological deficits – weakness, gait, and visual abnormalities have all been reported
  • If the thrombosis extends to the jugular vein, there will be signs of multiple cranial nerve involvement :

Lesions in the superior sagittal sinus can present with seizures and motor dysfunction

Lesions in the left transverse sinus may cause patients to be aphasic

Lesions in the cavernous sinus could present with periorbital pain and visual changes

Lesions in deep venous sinuses may present with altered mental status

Differentials

  • Infections – meningitis, encephalitis
  • Trauma
  • Benign intracranial hypertension
  • 6th Cranial Nerve Palsy
  • Stroke
  • Cavernous sinus thrombosis

Investigations and Imaging

  • Full blood count – increased hemoglobin due to polycythemia, decreased platelet count, and increased white blood cell count are all important factors
  • In patients suspected to have hereditary hypercoagulable states, appropriate diagnostic tests may be done such as protein c and S deficiency, antiphospholipid syndrome, factor V Leiden
  • Lumbar puncture may be done if meningitis or encephalitis is suspected to be the cause
  • D-dimer level

Various imaging modalities are used to diagnose CVT, or the conditions leading to it. 

  • CT Scan- hyperdensity in the lumen- dense clot sign & Empty delta sign (filling defect in the dural sinus)
  • CT Angio 
  • MRI
  • Magnetic Resonance Venogram (MRV)- Gold standard

1) Empty delta sign

2) Dense clot sign

3) MRV of the Cerebral Venous System (Saposnik 2011)

Treatment and Management

t is important to treat CVT, including its cause and complications. CVT treatment is quite similar to the treatment of stroke with the use of thrombolysis and anticoagulation. The treatment modalities have been controversial due to the risk of bleeding, but several studies conducted showed a much greater benefit of anticoagulation and thrombolysis in patients with CVT. Parenteral administration of Heparin or the use of Enoxaparin is preferred in the acute phase.

In patients who do not improve by anticoagulation treatment, thrombolytics are administered systemically or catheter directed. Common thrombolytics used are Tenecteplase and alteplase. After acute management, patients are prescribed warfarin for 3-6 months duration.

Treating the cause includes appropriate antibiotic coverage for infections, methods of lowering intracranial pressure, anticonvulsants for seizure control and care must be taken to prevent aspiration in patients with focal neurological deficits.

Prognosis

Death due to herniation is common, and decompressive surgery to prevent this has greatly reduced morbidity and mortality. The mortality associated with CVT is 5%.

Things To Consider

As the emergency physicians are the first ones to evaluate the patient, any patient who presents with stroke-like symptoms, headache – especially first occurrence and extremely painful, with a significant history of blood disorders or oral contraceptive use, CVT should be considered, and the appropriate tests must be ordered in order to make a timely diagnosis and begin management to prevent morbidity and mortality.

References and Further Reading

Cite this article as: Sumaiya Hafiz, UAE, "Cerebral Venous Sinus Thrombosis," in International Emergency Medicine Education Project, August 2, 2021, https://iem-student.org/2021/08/02/cerebral-venous-sinus-thrombosis/, date accessed: September 25, 2021

Recent Blog Posts By Sumaiya Hafiz

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.