Intracranial Venous Thrombosis Flashcards
Cavernous Sinus Thrombosis
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
Example Question:A 50 year old Caucasian female on holiday from Australia presents to the walk-in urgent care centre with four day history of left sided temporal headache, which is persistent and of gradual onset. In addition, she complains of double vision as well. She is known to have migraines but is relatively well-controlled. She is normally independent with no significant family history. She takes no regular medications except the oral contraceptive pill. On examination, you note a left sided loss of the afferent papillary reflex. She also has a loss of vertical gaze and is unable to adduct her left eye. She has a reduced sensation to light touch on the left forehead and cheek, not crossing the midline. What is the diagnosis?
> CAVERNOUS SINUS THROMBOSIS
Left space-occupying lesions Multiple sclerosis Right MCA territory ischaemic infarct Cavernous sinus thrombosis Migraine with aura
The patient describes a clear history of loss of her 3rd cranial nerve, possible involvement of the left 4th, with V1 and V2 branches of the left trigeminal nerve. The only structure involving all these cranial nerves (and classically with the sympathetic postganglionic neuron) is the cavernous sinus. The patient has a number of risk factors for venous thrombotic disease, including recent long-haul flight and the oral contraceptive pill. The most likely causes are dehydration and VTE disease risk factors, but a carotid artery aneurysm should also be considered.
Intracranial Venous Thrombosis
Intracranial venous thrombosis
Overview
- 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
Features
- headache (may be sudden onset)
- nausea and vomiting
Ix = MRI BRAIN WITH VENOGRAM
Sagittal Sinus Thrombosis
Sagittal sinus thrombosis
- may present with seizures and hemiplegia
- parasagittal biparietal or bifrontal haemorrhagic infarctions are sometimes seen
SEE Passmed CT Superior Sagittal Sinus Thrombosis
CT with contrast demonstating a superior sagittal sinus thrombosis showing 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
Lateral Sinus Thrombosis
Lateral sinus thrombosis
6th and 7th cranial nerve palsies
Cerebral Venous Thrombosis - Diagnosis and Ix: Example Question
A 42 year old presents with 6 days of drowsiness and a gradual onset but progressive headache, initially starting in the occipitum radiating to the apex. She has recently returned from Australia in holiday one week ago but has complained of poor appetite after a cough and cold since landing. She has no past medical history, takes no regular medications except the oral contraceptive pill. She is a non-smoker and drinks minimally. On examination, the patient has a full range of neck movements and no photophobia. Examination of her limbs is unremarkable. You request a CT head without contrast, which demonstrates two small areas of subarachnoid blood in right convexity. She denies any recent head trauma. Which investigation will most likely provide the conclusive diagnosis?
CT head with contrast MRI head > MR venogram Lumbar puncture with xanthochromia CT angiography
The patient presents with a non-specific headache on a background of a number of different risk factors for venous thromboembolic disease: recent long-haul flight, likely dehydration from poor oral intake, oral contraceptive pill. A generalised headache is present in almost 90% of all patients with cerebral venous thrombosis (CVT)1. The headache is caused by impaired absorption of cerebrospinal fluid due to the sinus thrombus, resulting in increased intracranial pressure. CVTs can also present with seizures, encephalopathy and focal symptoms, but be aware that the presenting clinical features can be extremely variable.
A plain CT head can sometimes demonstrate signs of CVT in one third of patients. A dense triangle sign is often seen in the posterior superior sagittal sinus. In addition, the empty or negative delta sign2, is seen on a contrasted CT head where a central area is lacking contrast flow due to thrombus obstruction. However, MR venogram (CT venogram in the hands of highly skilled radiologists) is the most sensitive imaging modality.
This scenario is a useful demonstration that not all subarachnoid blood equates to a sponatenously rupture aneurysm. Cerebral venous thrombosis is a classic cause of intraparenchymal and subarachnoid haemorrhages, particularly if around the convexity3. In addition, the description of the headache is atypical for aneurismal subarachnoid haemorrhage: the headache is of gradual onset, persists for days, with no meningism. Although it may seem illogical, treatment with anticoagulation will treat the sinus thrombus, resulting in improved CSF flow, while the subarachnoid blood will slowly resolve.
Superior Sagittal Thrombosis
SEE PASSMED SUPERIOR SAGITTAL SINUS THROMBOSIS
The CT with contrast demonstates a superior sagittal sinus thrombosis showing 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.
Intracranial Venous Thrombosis - Example Question
A 28-year-old woman presents with a gradually worsening headache, nausea and vomiting.
The headache started about 3 days ago coming on over about 3-4 hours and is worse on coughing and lying flat. She has been complaining of some nausea and vomiting which she had attributed to some reheated curry she had the night before.
She is usually fit and well but did suffer a spontaneous below-knee deep vein thrombosis (DVT) 3 years ago which was treated with warfarin for 6 months. She has been taking over-the-counter paracetamol and ibuprofen for the headache and currently has a Mirena intrauterine coil in-situ for contraception. She has no known drug allergies.
She currently works as a sales associate. She smokes 10 cigarettes a day and drink 21 units of alcohol a week.
On examination she looks unwell, pale and nauseated. Her blood pressure was 140/98 mmHg, heart rate 100 bpm, oxygen saturations of 98% on air. Her temperature was 36.1 degrees Celsius.
Heart sounds were normal, and her calves soft and non-tender with no evidence of thromboembolism.
Her chest was clear and her abdominal examination was unremarkable.
On neurological examination there was no cranial nerve abnormalities noted. She had normal tone, power, reflexes and sensation in both her upper and lower limbs. Coordination was intact.
Bloods taken by the Emergency Department were as follows:
Na+ 136 mmol/L K+ 3.9 mmol/L Urea 4.8 mmol/L Creatinine 76 µmol/L Hb 12.5 g/dL WBC 11.0 x 10^9/L Platelets 350 x 10^9/L INR 0.9 aPTT 30 seconds LFTs Normal
CT head was performed and reported as normal.
Following this a lumbar puncture was performed:
CSF colour Clear
Opening pressure 250 mmH20
White cell count 5.0 x 10^6/L (all lymphocytes)
Red cell count 15 x 10^6/L
Protein 0.3 g/L
Glucose 4.4mmol/L (Serum glucose 5.3mmol/L)
What is the most likely diagnosis?
> Intracranial venous thrombosis Subarachnoid haemorrhage Migraine Intracerebral malignancy Subdural empyema
This lady has had a previous venous thromboembolism and presents with a gradually worsening headache with multiple red flags. The history and examination is rather non-specific but it is the CSF opening pressure in the context of previous venous thrombus that most points towards the diagnosis of an intracranial venous thrombosis. This can present with a gradual or severe headache, signs of raised intracranial pressure and cranial nerve palsies.
Subarachnoid haemorrhage is unlikely in the context of the gradual onset of symptoms.
This patient has no previous history of migraine and the investigations are not consistent with this.
She is apyrexial and there is nothing in her presentation to indicate an intracerebral abscess, furthermore the CT is normal.
A normal CT also rules out intracerebral malignancy.
IVT - Difficult Diagnosis: Example Question
A 27 year-old woman attends the neurology clinic complaining of headache and visual disturbance. She has recently immigrated from Ghana. Her symptoms began approximately one month ago, shortly after the birth of her first child. She experiences dull frontal headache which is worst in the mornings and on coughing or straining, as well as transient episodes of ‘darkening’ of her vision. She saw a doctor in Ghana and was diagnosed with idiopathic intracranial hypertension. She is taking acetazolamide 250mg BD and no other medication.
On examination the visual fields are markedly constricted and the right blind spot is enlarged. Fundoscopy shows bilateral papilloedema worse on the right. The remainder of the neurological examination is unremarkable. BMI is 18 kg/m².
Plain computed tomography of the brain is normal.
Incidentally as she is leaving the clinic she mentions that she has also been experiencing pins and needles in the hands and feet.
What is the best course of action?
Increase dose of acetazolamide Request nerve conduction studies Organise for therapeutic lumbar puncture Refer to neurosurgeons for consideration of ventriculo-peritoneal shunting > Request CT venography
The history of headache suggestive of raised intracranial pressure associated with transient visual obscurations, as well as the examination findings, are all compatible with idiopathic intracranial hypertension (IIH). However, the onset of symptoms in the puerperium, in a slim patient with no other risk factors for IIH, raises the suspicion that this may actually be a cerebral venous sinus thrombosis. All patients with IIH should have imaging of the venous system with CT or MR to exclude a thrombus which can be more appropriately treated with anticoagulation.
Therapeutic lumbar puncture can ease the headache of IIH but is a short-term measure. Ventriculo-peritoneal shunting can be used where medical management has failed.
There is no role for nerve conduction studies in this patient. Paraesthesia are a common side effect of acetazolamide, and this patient is unlikely to tolerate an increase in the dose.
Ruling out Venous Sinus Thrombosis in Idiopathic Intracranial HTN: Example Question
A 25-year-old woman presents to the neurology outpatient clinic with a month history of worsening headache.
The headache is mostly frontal in nature but does move to the back of her head sometimes. It never goes away but is worst in the morning. It is throbbing in nature. In the last week it has begun to make her feel sick, although she has not vomited. She has also developed a thudding sound in her ears which she first noticed when trying to go to sleep at night but now sometimes hears at other times. She has no change in her vision or photophobia.
She has no past medical history of note and has no allergies. Her only current medication is the oral contraceptive pill. She is obese, drinks no alcohol and smokes ten cigarettes per day.
On examination her heart rate is 90/min and her blood pressure is 165/94 mmHg.
Her pupils are equal and reactive and her visual fields are full to confrontation. Vision is 6/6 in both eyes and extra-ocular movements are normal. Fundoscopy reveals slight blurring of the optic disc margins with a normal retina.
Examination of the other cranial nerves reveals no deficits. On examination of the upper and lower limbs, tone, power, coordination and reflexes are all normal, with downgoing planters. Her BMI is 31.
Blood tests:
Hb 150 g/l
Platelets 250 * 109/l
WBC 7 * 109/l
Na+ 136 mmol/l
K+ 4 mmol/l
Urea 6 mmol/l
Creatinine 72 µmol/l
What is the next most appropriate imaging investigation?
CT angiogram head CT head without contrast MR angiogram head MRI head without contrast > MR venogram head
This lady has headache, worse on laying down, associated with nausea, pulsating tinnitus and papilloedema. These symptoms are suggestive of raised intracranial pressure and idiopathic intracranial hypertension. She is high risk for this condition given her young age, obesity and use of the oral contraceptive pill.
The diagnosis is supported by her lack of localising neurology. She does not yet have signs of visual impairment.
Formal diagnosis (by Modified Dandy criteria), requires CSF opening pressure greater than 25 cmH2O and normal brain imaging. Imaging is required to exclude venous sinus thrombosis, which could result in the same signs and symptoms and is also more common in women on the oral contraceptive pill. The gold standard imaging for this would be MRI with contrast of the head and orbits and MR venogram
