intracranial venous thrombosis Flashcards
define
= thrombus present within one of the dural venous sinuses
can cause cerebral infarction, much lesson common than arterial causes
50% of patients have isolated sagittal sinus thromboses - the remainder have coexistent lateral sinus thromboses and cavernous sinus thromboses
There are three key types of venous sinus thrombosis:
- cavernous sinus thrombosis
- sagittal sinus thrombosis
- lateral sinus thrombosis
s/s
Features
- headache (may be sudden onset)
- nausea & vomiting
Sagittal sinus thrombosis
- may present with seizures and hemiplegia
- parasagittal biparietal or bifrontal haemorrhagic infarctions are sometimes seen
Cavernous sinus thrombosis
- other causes of cavernous sinus syndrome: local infection (e.g. sinusitis), neoplasia, trauma
- periorbital oedema
- ophthalmoplegia: 6th nerve damage typically occurs before 3rd & 4th
- trigeminal nerve involvement may lead to hyperaesthesia of upper face and eye pain
- central retinal vein thrombosis
Lateral sinus thrombosis
- 6th and 7th cranial nerve palsies
ix of cerebral venous sinuses
- blood cultures for infection
- lumbar puncture, which may show:
- slightly raised CSF pressure
- increased protein
- pleocytosis, indicating a spread of infection to neighbouring leptomeninges
- CT scan - so as to discriminate from cerebral abscess, which is difficult on clinical grounds alone. Delta sign - filling defect within the sinus following contrast administration - seen in superior sagittal sinus thrombosis.
- MRI scan - now succeeding CT as an investigative mode
- carotid angiography - if blockage of cavernous sinus, there may be an obvious filling defect in the venous phase after administration of contrast.
mx
The treatment of cerebral venous thrombosis entails consideration of the underlying aetiology:
primary thrombosis - anticoagulants with adequate attention given to the risk of haemorrhage
- people diagnosed with cerebral venous sinus thrombosis (including those with secondary cerebral haemorrhage) should be given full-dose anticoagulation treatment (initially full-dose heparin and then warfarin [INR 2–3]) unless there are comorbidities that preclude its use
secondary thrombosis:
- antibiotics if infectious
- anticonvulsants
- surgical drainage of sinuses if these are the source of infection
- mastoidectomy may be indicated if the cause was an acute mastoiditis
- anticoagulants are unlikely to be required
- high dose dexamethasone to reduce cerebral oedema
prognosis
- primary thrombosis - prognosis is likely to be poor since the condition has developed as a complication of a generally serious pre-existing condition.
- secondary thrombosis - there may be some residual disability, including epilepsy. The outlook has improved tremendously with advances such as antibiotics for infective thrombophlebitis.
common causes: [aetiology]
- Pregnancy / puerperium
- OCP
- Head injury
- Dehydration
- Intracranial / extracranial malignancy
- Thrombophilia
ddx
[SAMIE]
- SAH
- Meningitis
- Encephalitis
- Intracranial abscess
- Arterial infarction (stroke)
TYPICAL CT OF INTRACRANIAL VENOUS THROMBOSIS
- CT with contrast demonstating a superior sagittal sinus thrombosisshowing the typical empty delta sign.
- Look at the ‘bottom’ of the scan for the triangular shaped dural sinus.
- This should normally be white due to it being filled with contrast.
- The empty delta sign occurs when the thrombus fails to enhance within the dural sinus and is outlined by enhanced collateral channels in the falx.
- This sign is seen in only about 25%-30% of cases but is highly diagnostic for sagittal sinus thrombosis
Cortical venous occlusion: definition
- Often → venous infarcts w/ stroke-like focal symptoms that evolve over days
- occurs with sinus thrombosis
- causes underlying infarction and haemorrhage.
cortical venous occlusion: aetiology
Primary, or aseptic, cerebral venous thrombosis is rare. It usually occurs in the very young, the very old, or the debilitated. Predisposing factors include:
- anaemia
- increased blood coagulability
- hypotension
- cachexia
- dehydration
Causes of secondary thrombosis include:
- most frequently, direct injury through a fracture of the skull or other trauma
- spread of infection from a neighbouring site:
- cavernous sinus and sagittal sinus thrombosis - from infection of the face, or of the sphenoid, frontal or ethmoid sinuses
- lateral sinus thrombosis from mastoiditis
- furunculosis and cutaneous sepsis
- pregnancy, puerperium
- oral contraceptive pill
- dehydration
- haematological disease, for example polycythaemia
- malignancy - metastatic emboli
- miscellaneous, including polyarteritis nodosa
cortical venous occlusion: pathogenesis
The thrombosed venous sinus bears a loose, red clot initially which with time becomes pale and adherent to the vessel walls. If there is an infective aetiology, the clot may itself become colonised, and this infection can spread locally to the leptomeninges or to an abscess, or systemically via septic emboli.
The territory of the affected sinus shows congestive oedema and even haemorrhagic venous infarction.
cortical venous thrombosis: s/s
- focal neurological signs - more likely to cause bilateral signs, e.g. paraplegia rather than a hemiparesis
- epilepsy - partial or generalised
- fever
- features of sinusitis or otitis media if infection is present
cortical venous thrombosis: ix
- blood cultures for infection
- lumbar puncture, which may show:
- slightly raised CSF pressure
- increased protein
- pleocytosis, indicating a spread of infection to neighbouring leptomeninges
- CT scan - so as to discriminate from cerebral abscess, which is difficult on clinical grounds alone. Delta sign - filling defect within the sinus following contrast administration - seen in superior sagittal sinus thrombosis.
- MRI scan - now succeeding CT as an investigative mode
- carotid angiography - if blockage of cavernous sinus, there may be an obvious filling defect in the venous phase after administration of contrast
cortical venous thrombosis mx
= same as intracranial venous thrombosis mx!
