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dural_sinus_thrombosis

cerebral dural venous sinus thrombosis (CVST)

see also:

Introduction

  • thrombosis of the cerebral venous sinus is a rare, potentially life threatening condition which causes raised intracranial pressure (ICP)
  • adult prevalence is 3-16 cases per million population per year with 75% being female and mainly in young adults, presumably due to pregnancy and combined oral contraceptive pill (OCP) being the prime causative factors
  • in children, annual prevalence is around 7 per million children, some 40% of these occur in neonates, mostly in dehydrated, unwell neonates
  • first recognized as a cause of death in 1825, but pre-mortum diagnosis on clinical grounds occurred in the 1940's, but only became radiologically possible with the advent of venography in 1951

Anatomy

  • the cerebral venous sinuses (aka dural venous sinuses) drain blood from the brain into the internal jugular veins and differ from normal veins in that their walls lack a full set of layers (there is no tunica media, and instead are dura mater lined with endothelial cells).
  • they do not have venous valves

Aetiology

Clinical features

    • present in 90%, may be of sudden onset but usually progressively worsens over several days
  • the elderly may not have headache but may present with delirium or decreased consciousness
  • usually, the headache is associated with other features which may include:
  • may have a raised D-Dimer pathology test but not excluded by a negative result

Diagnosis

  • a negative D-Dimer pathology test when combined with absence of risk factors or other clinical features may suffice to sufficiently rule out acute CVST although there is currently inadequate evidence to support this and this needs further study
    • D-Dimer is more likely to be “falsely” negative if:
      • CVST is more than 30 days old
      • isolated headache only
      • single sinus involvement
  • CT brain non-contrast to exclude other causes such as subarachnoid haemorrhage (SAH)
  • CT brain venogram (venous phase IV contrast scan)
    • 75-100% sens and 80-100% spec.
    • “empty delta sign” may be observed in 1st two weeks
    • alternatively MRI venogram can be used

Mx

Prognosis

  • 8-9% mortality rate
  • poor prognostic factors:
    • children with seizures or evidence of venous infarction
    • adults aged over 37yrs
    • men
    • coma or mental state disorder
    • intracerebral haemorrhage
    • thrombosis of the deep cerebral venous system
    • central nervous system infection
  • of survivors, over 80% have a full or near full recovery
dural_sinus_thrombosis.txt · Last modified: 2021/04/09 12:28 by gary1