Intracranial Venous Thrombosis - IVT Flashcards
What are the two types of IVT?
1) Dural Venous Sinus Thrombosis
2) Cortical Vein Thrombosis
Where does Dural Venous Sinus Thrombosis usually occur?
Most commonly sagittal sinus thrombosis - 47%
or transverse sinus thrombosis - 35%
Also sigmoid sinus, inferior petrosal sinus, cavernous sinus
How quickly do the symptoms develop?
They come on gradually over days or weeks.
Are dural venous thrombi confined to the dural system?
No, thrombus within the dural sinus may extend into the cortical veins and cause infarction within a venous territory.
What are the symptoms of thrombi in
1) Sagittal sinus
2) Transverse sinus
3) Sigmoid sinus
4) Inferior petrosal sinus
5) Cavernous sinus
1) Sagittal sinus - Headache, vomiting, seizures, decreased vision, papilloedema
2) Transverse sinus - Headache +/- mastoid pain, focal CNS signs, seizures, papilloedema
3) Sigmoid sinus - Cerebellar signs, lower cranial nerve palsies
4) Inferior petrosal sinus - Vth and VIth cranial nerve palsies which, with temporal and retro-orbital pain, comprise Gradenigo’s syndrome
5) Cavernous sinus - Often due to spread from facial pustules or folliculitis, causing headache, chemosis, oedematous eyelids, proptosis, painful opthalmopegia, fever.
What is Gradenigo’s syndrome?
A triad of symptoms consisting of 1) periorbital unilateral pain related to trigeminal nerve involvement, 2) diplopia due to sixth nerve palsy and 3) persistent otorrhea, associated with bacterial otitis media with apex involvement of the petrous part of the temporal bone (petrositis).
The classical syndrome related to otitis media has become very rare after the antibiotic era.
What are the characteristics and timeframe of cortical venous thrombosis?
Often causes venous infarcts with stroke like symptoms which develop over days.
The associated headache may come on suddenly ‘thunderclap headache’,
Seizures are common, unlike in arterial stroke, and focal.
It usually occurs along with sinus thrombosis.
What are the signs of CVT?
- Encephalopathy
- Focal seizures
- Headache (including the thunderclap headache)
- slowly evolving focal deficits e.g. paresis, speech disorders, decreased cognition and vision
What are the differential diagnoses for Intracranial Venous Thrombosis?
1) Subarachnoid haemorrhage - The thunderclap headache can occur in direction of the carotid and vertebral artery, and in benign thunderclap headache (triggered by Valsalva manoeuvre e.g. cough, coitus)
2) Meningitis
3) Encephalitis
4) Intracranial abscess
5) Arterial infarction
What are the common causes of IVT?
- Pregnancy/puerperium
- Oral contraceptives
- Head injury
- Dehydration
- Blood dyscrasias
- Intracranial malignancy (local invasion/ pressure)
- Extracranial malignancy (hypercoagulability)
- Recent LP
What are the systemic causes of IVT?
- Hyperthyroidism
- Nephrosis
- Ketoacidosis
- Heart failure
- SLE
- Homocystinuria
- Hyperviscosity
- Crohn’s or UC
- Bechet’s disease
- Activated protein c resistance
- Antiphospholipid syndrome
- Klippel-Trenaunay syndrome
- Paroxysmal nocturnal haemoglobinuria
What are the infectious causes of IVT?
- Meningitis; TB
- Cerebral abcess
- Septicaemia
- Fungal infections
- Otitis media
- Cerebral malaria
- HIV with nephrosis
What are the drug causes of IVT?
- Androgens e.g. oxymetholone
- Antifibrinolytics e.g. transexamic acid
- Infliximab
What are the investigations that you would carry out for suspected IVT?
1) EXCLUDE Subarachnoid Haemorrhage.
2) Check there are no sign of meningitis
Imaging: CT/MRI venography may show signs of absence of sinus (absent transverse can be a normal variant)
MRI T2 weighted gradient echo sequences can normally visualise thrombus directly and also identify haemorrhage infarction.
CT may be normal early, then at week 1 develop delta sign where a transversely cut sinus shows a contrast filling defect.
Lumbar Puncture: perform unless contraindicated by CT/MRI, If raised opening pressure, with persistent headache and excluded SAH, suspect CVT.
CSF may be normal or show red cells and xamthochromia
What is the management of IVT?
Seek expert help.
Heparin improves outcomes, possibly even in those with haemorrhagic venous infections.
Fibrinolytics (e.g. streptokinase) have been used via selective catheterisation.
Thrombophilia screen and ENT review to help identify cause.
