Background
- Thrombus develops in the venous or dural sinus:
- ↓ CSF absorption → ↑ICP
- ↑capillary pressure damages blood brain barrier = haemorrhage (subarachnoid or intra-parenchymal)
- Vasogenic oedema
- ↑intravasc. venous pressure = venous infarction
- F:M = 3:1 (mean age 37
- Pregnancy, OCP, thrombophilia, neoplasm predispose
- Many have an underlying trigger:
- Pregnancy / puerperium
Known or familial thrombophilia / hypercoagulable states, malignancy - Sinusitis (Staphylococcal ± dural abscess)
- Recent trauma or surgery
- LP or post LP intracranial hypotension
- Pro-thrombotic medications (OCP, HRT, Steroids)
- Inflammatory bowel disease, sarcoidosis
- Arteritic conditions (e.g. SLE etc.)
Prognosis
- Majority make a full recovery (if treated early)
- 10- 30% die (mainly ↑ICP with herniation in delayed Dx)
Clinical
Common
- Headache (± thunderclap), ↑ICP (N&V)
- ↑ICP = vomiting, papilloedema
- May present with infarction (cortical or saggital clot) stroke
- May present with progressive headache or ocular / bulbar symptoms (cavernous sinus clot):
- Ocular symptoms
- Pulsatile tinnitus
- Unilateral deafness
- Facial N. lesion
- Occasionally bilateral lower limb weakness
Signs
- Altered mental status
- Cranial nerve palsy
- Papilloedema / retinal haemorrhages
- Focal long tract signs
Differential Dx (no trauma)
Differential Dx (no trauma)
Investigations
- CT (outrule other mass lesion), then MRI (MRV)
- D-dimers (Sensitivity 97%, Specificity 91% Ref1)
- FBC (polycythaemia or platelet abnormalities)
- Thrombophilia screen
- Sickle cell test, where appropriate
- ESR and auto-antibodies
- Urinalysis (protein)
- EEG (particularly if ? seizures)
Management
- Manage as arterial stroke
- Refer "stroke" team
- Consider anticoagulation (LMWH or Heparin infusion)
- Beware and prompt Mx seizures (common)
- Seek underlying and treat (e.g. sinusitis, meningitis)
- Progressive unilateral herniation may be amenable to decompressive neurosurgery
- Early ITU involvement
Prognosis
- Mortality is 5-15%
The CVT risk score helps to estimate prognosis:
- Presence of malignancy – 2 points
- Coma on admission – 2 points
- Thrombosis involving the deep venous system – 2 points
- Mental status disturbance on admission – 1 point
- Male sex – 1 point
- Intracranial haemorrhage on admission – 1 point
Score ≥3 is associated with a poor outcome.
Links
- Ref1. Kosinski CM, Mull M, Schwarz M, et al. Do normal D-dimer levels reliably exclude cerebral sinus thrombosis?. Stroke. Dec 2004;35(12):2820-5