Intracranial Venous Thrombosis Flashcards
What are dural venous sinuses? Where do they drain to?
Dural Venous Sinuses are endothelium-lined venous channels located between the meningeal and periosteal dural layers in the brain (resistant to compression due to their position between rigid layers.)
**They collect blood from different intracranial venous systems (cerebrum, cerebellum, brainsteam) and drain into the internal jugular veins. **
Most common form of dural venous sinus thrombosis.
Sagittal sinus thrombosis.
List the types of dural venous sinus thrombosis.
1) Sagittal sinus thrombosis.
2) Transverse sinus thrombosis.
3) Sigmoid sinus thrombosis.
4) Inferior petrosal sinus thrombosis.
5) Cavernous sinus thrombosis.
Features of each type of dural sinus thrombosis.
Sagittal: headache, vomiting, seizures, decreased vision, papilloedema.
Transverse: headache +/- mastoid pain, focal CNS signs, seizures, papilloedema.
Sigmoid: cerebellar signs, lower CN palsies.
Inferior petrosal: 5th and 6th CN palsies with temporal and retro-orbital pain (Gradenigo’s syndrome— suggests that otitis media is the cause).
Cavernous (often due to spread from facial pustules or folliculitis, causing headache, chemosis, oedematous eyelids, proptosis, painful ophthalmoplegia, and fever.
What is cortical vein thrombosis?
Usually occurs with a sinus thrombosis as it extends into the cortical veins, causing infarction in a venous territory.
These infarcts give rise to stroke-like focal symptoms that develop over days. There are often seizures and an associated headache which may come on suddenly (thunderclap).
A 42-year-old woman presents to the emergency department with severe headache, fever, and swelling around her left eye. She reports that the symptoms began 3 days ago with a mild headache and gradually worsened. She also mentions a recent history of a facial infection that was treated with antibiotics. On physical examination, the patient has periorbital edema, proptosis, and ophthalmoplegia of the left eye. Her temperature is 38.5°C (101.3°F), and she has tenderness over her left forehead and cheek. Neurological examination reveals left-sided sixth cranial nerve palsy.
What is the most likely diagnosis?
Cavernous sinus thrombosis.
Causes of dural venous sinus thrombosis.
Numerous.
> Anything that produces a hypercoagulable state.
Common causes:
-Pregnancy
-COCP
-Head injury
-Dehydration
-Blood dyscrasias
-Tumours (local invasion/pressure)
-Extracranial malignancy (hypercoagulability)
-Recent LP
Other causes:
Infection
Drugs (antifibrinolytics, androgens)
SLE
Vasculitis
Crohn’s
UC
Intracranial venous sinus thrombosis investigations.
Exclude SAH (if thunderclap headache present) and meningitis.
Bloods: thrombophilia screen.
Imaging: CT/MRI venography may show absence of a sinus though an absent transverse sinus can be a normal variant.
MRI T2-weighted gradient echo sequences can visualise thrombus directly and also identify haemorrhagic infarction.
CT may be normal initially, but show filling defect at ~1 week (delta sign).
LP (if no CI): raised opening pressure.
CSF may be normal or show RBCs and xanthochromia.
Management of dural venous sinus thrombosis.
Seek expert help.
Treat underlying infection.
Anticoagulation with heparin or LMWH then warfarin (INR 2-3) may benefit even if there is secondary cerebral haemorrhage (unless otherwise CI).
If there is deterioration despite adequate anticoagulation, endovascular thrombolysis or mechanical thrombectomy may provide limited benefit (but not in those with large infarcts and impending herniation).
Increased ICP requires prompt attention. Decompressive hemicraniectomy may prevent impending herniation.
What is the most common cause of Cavernous Sinus Thrombosis? What is usually a clue from the history?
Infection.
Facial or eye infection e.g. sinusitis may precede 5-10 days before presenting with CST symptoms e.g. headache and eye symptoms.
How does infection typically spread to cause Cavernous Sinus Thrombosis?
Infection typically spreads from an extracranial location such as the orbit, paranasal sinuses, or the ‘danger zone’ of the face.
What are common clinical features of Cavernous Sinus Thrombosis?
Common clinical features include severe headache, unilateral periorbital oedema, proptosis, photophobia/diplopia, and cranial nerve palsies.
Progressive and not-intermittent
Which cranial nerve is most commonly affected in CST?
The abducens nerve (CN VI)
What is the typical treatment for CST?
Treatment is typically with antibiotic therapy.
Heparin may be used to dissolve clot.
What can happen if the cause of Cavernous Sinus Thrombosis is infection without prompt antibiotic treatment?
Meningitis.
