Umbrella term of multiple types of venous thrombosis, which present differently.
- Dural sinus thrombosis
- Sagittal (MCC ~50% of all thromboses) – but anterior superior sagittal sinus can occlude without symptoms
- Transverse (35%)
- Inferior petrosal
- Cortical vein thrombosis
- Deep vein thrombosis
Thrombosis reduces venous outflow, reducing flow through a venous territory. Engorgement produces oedema, and eventually infarction or haemorrhage, all of which increase ICP.
Risk factors include pregnancy/oral contraceptive, trauma, malignancy, thrombophilia and dehydration.
Classic presenting complaint
- Young female
- Subacute* (days-weeks) headache, N&V, visual disturbance
- Can look like idiopathic intracranial hypertension (pseudotumour cerebri)
*Headache can start or worsen suddenly and mimic a thunderclap headache.
- Papilloedema (Sagittal, transverse)
- Mastoid tenderness (Transverse)
- Cerebellar signs (Sigmoid)
- Gradenigo’s syndrome (Inferior petrosal)
- CN V and VI palsy
- Temporal and retro-orbital pain
- Subacute hemiplegia/dysarthria/dysphasia (cortical vein)
- Focal seizures (cortical vein)
Clinical approach & differential
- Carotid/vertebral dissection
- Benign thunderclap headaches
- Stroke (arterial)
- Space occupying lesion
- Urgent non-contrast CT head to exclude SAH or other acute haemorrhage
- Consider CTA, MRA or MRV – seek advice from radiology
- MRI T2 GE sequences visualise venous clot
- If CT/imaging normal and low chance of herniation >> LP
Erm… this one is complicated. Bleep radiology…
Absence of venous sinus on MRV could be an indication of thrombosis, but also could be normal variant.
Filling defects can be seen late on CT.
- Thrombophilia screen
- Medicines review
- ENT review