Cerebral Venous Sinus Thrombosis

A 23 year old female presents to ED after waking up with loss of balance, dysphasia, and mild right sided arm and leg weakness. Normally fit and well, she reported preceding nausea, vomiting, dizziness and intermittent headache for 2 days. 

Meds - OCP 

On Examination

  • Awake and alert
  • R sided neglect
  • Expressive and receptive aphasia
  • Unable to obey 3 stage command
  • Weakness 4/5 right upper and lower limb, compared with 5/5 on left side.

Look at the CT Scan

+ What does the non contrast CT show?

  • Hyperdense appearance of superior sagittal vein, suggestive of extensive dural venous sinus thrombosis.
  • Subtle loss of grey white matter in L frontal cortex - ? venous infarct
  • Dense clot sign in cerebral veins
  • Dense transverse sinus due to thrombosis
  • CT Venogram recommended

+ What are the main CT features on venogram?

  • Look for filling defects in sinuses - hyperdensity confirmed within dural venous sinus. It is extensive and within the cortical dural veins at the vertex, the superior sagittal sinus, straight sinus, torcula, left transverse and sigmoid sinuses. Thrombosis extends into the great cerebral vein of Galen.
  • empty delta sign (95% sensitivity - see image below)

The empty delta sign is CT sign of dural venous sinus thrombosis of the superior sagittal sinus, where contrast outlines a triangular filling defect (clot). It is only described with contrast-enhanced CT-scan or MRI, not non contrast CT (or MRI)

+ What is cerebral venous thrombosis?

Occlusion of venous channels in the cranial cavity including:

  • dural venous thrombosis
  • cortical vein thrombosis
  • deep cerebral vein thrombosis

Source: (adapted from) Radiology Assistant

+ What are the risk factors for CVT?

  • Hormonal factors - e.g oral contraceptive pill
  • Pregnancy
  • Post partum
  • Steroid use
  • Pro thrombotic states
  • Intracranial space occupying lesion
  • Infection - e.g mastoid sinus
  • Systemic illness - dehydration, sepsis, malignancy

+ What are the main symptoms?

These can be non specific but may include:

Symptoms

  • Headaches, nausea & vomiting
  • Altered mental state
  • Altered vision / reduced acuity

Signs

  • Papilloedema
  • Focal deficits
  • Seizures

+ What is the management

  • Resuscitation (coma, seizures, ICP) and good supportive care
  • Anticoagulation with heparin (even if haemorrhagic venous infarction)
  • Interventional radiologists can perform catheter directed thrombolysis in affected sinuses.
  • Refer to neurology and haematology
  • Identify and treat causes (e.g cease OCP)
  • Manage complications - e.g seizure prophylaxis

+ What are the potential complications

  • Most will have a good recovery
  • Some will have ongoing symptoms
  • Death - mortality around 5%
  • Features predicting worse outcomes:
    • Involvement of deeper veins
    • malignancy
    • Intracranial infection
    • Concurrent haemorrhage
    • Altered mentation
    • older age