• Clinical science

Cerebral venous thrombosis

Abstract

Cerebral venous thrombosis (CVT) is a thrombotic obstruction of the cerebral venous system that may lead to ischemic lesions (or hemorrhages) in the brain. The condition can occur in all age groups and affects women more than men, who have a higher risk of predisposing factors such as prothrombotic conditions, pregnancy, oral contraceptive use, malignancy, and infection. Headaches are a typical presenting manifestation of CVT, while focal neurological deficits, seizures, and increased intracranial pressure may develop as the disease progresses. Diagnosis is established by visualizing the cerebral veins and dural sinus with neuroimaging methods (CT and MRI with radiocontrast). Management may include treating underlying causes and neurological symptoms as well as administering systemic anticoagulation or thrombolysis. Surgical intervention in the form of direct clot lysis, recanalization or shunt placement for raised ICP, can be indicated if medical management is insufficient.

Definition

CVT, also known as cerebral venous sinus thrombosis, is a thrombotic obstruction of the cerebral veins and/or related anatomical structures (dural sinuses) which drain blood from the brain.

Epidemiology

  • Sex: > , 3:1
  • Age of onset: ≤ 40 years
  • Prevalence: 3–4 cases per million in adults; 7 cases per million in neonates .

References:[1][2]

Epidemiological data refers to the US, unless otherwise specified.

Etiology

Noninfectious

Infectious

References:[3][4][5]

Pathophysiology

  • Thrombogenesis occurs in the cerebral venous system, including the dural sinuses ↓ cerebral drainageintracranial pressure → clinical features; ; (see below)
  • Additionally, thrombus formation → congestion within the venous system of the brain → blood stasis → ↓ oxygenated blood in brain tissue → cerebral edema and/or infarcts/stroke

References:[1][4]

Clinical features

Since the thrombus develops gradually, clinical symptoms appear progressively and may initially fluctuate in magnitude.References:[4][3][1]

Diagnostics

If CVT is suspected, D-dimer levels and imaging studies are first steps of diagnosis

  • D-dimers: > 500 μg/L
  • Imaging:
    • CT/MRI (with or without venography): tests of choice to confirm the diagnosis
      • Plain CT/MRI help detect only edema and/or infarcts, but the thrombus itself can be visualized by means of venography.
      • CT :
        • Hypodense structures indicate ischemic event
        • Thrombus can appear as a hyperdense vein or sinus
        • CT venography shows a filling defect in a vein or sinus
      • MRI
        • Thrombus is isointense on T1 and hypointense on T2 early in the disease
        • Cerebral edema can be identified
        • MR venography demonstrates a lack of flow

  • Evaluation for possible causes
  • EEG: indicated if seizures are present
    • Determines seizure focus
    • May show focal abnormalities if a unilateral infarct occurs

References:[3][6][4][7]

Treatment

Initial management consists of treating underlying causes, general stabilization procedures , and antithrombotic therapy, which is the mainstay of treatment for CVT. Only if there is no improvement shown with medical therapy, is surgical intervention considered.

Medical therapy

Surgical therapy

  • Indications
    • Progressive neurologic worsening (despite adequate anticoagulation)
    • Acute rise in intracranial pressure
    • Impending herniation
  • Surgical options:
    • Blood clot removal
    • Vessel recanalization
    • Shunt placement

References:[8][3]