CEREBRAL VENOUS SINUS THROMBOSIS BY Aminu Arzet Department of Medicine Nelson Mandela School of Medicine University of K-Natal Durban 22nd October,2015

CONTENTS

IntroductionEpidemiologyPathogenesisClinical featureInvestigationsTreatmentPrognosisReference

Introduction Dural sinus thrombosis is also known as Cerebral venous

sinus thrombosis, or Cranial sinus thrombosis.

It refers to presence of blood clot inside Dural sinuses and/or cerebral veins

Dural sinuses receive blood from internal and external veins of the brain, also receive cerebrospinal fluid (CSF), then ultimately empty into the internal jugular vein

DST is a form of cerebro vascular accidents(CVA), and the least common of all forms of stroke.

ANATOMY OF DURAL VENOUS SINUSES

Epidemiology

DST account for 0.5% to 1% of all stroke cases.

Roughly affect 5 people / 1 million.

Prevalence of 3 – 9% across globe

Commonest in Middle east, particularly Saudi Arabia, due high prevalence of Behcet’s dx (an important risk factor for DST).

Commoner in young then old - Ration 5:1

Affect more women then men - Ratio 3:1

Etiology The exact etiology is not known

How ever it can be conveniently linked to Virchow's triad: blood stasis, changes in vessel wall, and changes in composition of blood.

Continuation of Etiology

Risk Factors:

Exogenous hormones; e.g oral Contraceptive (estrogen type)

Genetic causes ; inherited thrombophilia's

Mutation: Factor V Leiden Gene mutation and Prothrombin G20210A Mutation

Pregnancy and puerperium; particularly 3rd trimester

Malignancy; Hematological /pressure symptom/chemo

Continuation of Etiology

Infections; Mastoiditis,Sinusitis,Meningitis, ear/face infection

Trauma to head/neck

Head and neck surgical procedures Other Prothrombotic conditions:- Antithrombin III, Protein C, and Protein S Deficiency- Resistance to Activated Protein C - Antiphospholipid and Anticardiolipin Antibodies- Hyperhomocysteinemia- Polycythemia vera

Continuation of Etiology

Other risk factors: - Nephrotic syndrome - Bechet's disease - Iron deficiency anemia - Paroxysmal nocturnal hemoglobinuria / homocystinuria- Heparin induced thrombocytopenia / TTP- Sickle cell disease- Inflammatory bowel disease - Multiple myeloma- Epidural blood patch/Lumbar puncture.

Pathogenesis Veins of the brain drain blood into Dural venous sinuses,

which forward the blood to the heart via internal jugular vein

In DST blood clot/s is formed inside the veins of the brain and the venous sinuses.

Formation of clot/s inside the Dural sinuses/veins, blocks outward movement of blood to the heart, with resultant backflow, increased venous pressure, congestion and engorgement of the blood vessels and near by brain tissues. decreased

Continuation of Pathogenesis

This leads to decreased capillary perfusion, disruption of blood brain barrier, plasma leakage into interstitial space, cerebral edema, venous infarction(damage to brain tissue due to congestion), and eventfully small petechial haemorrhages develop, which may coalesced into large haematomas.

Thrombosis of the sinuses also lead to decreased resorption of CSF, stasis, and increased intracranial pressure, which could lead intracranial hypertension.

Clinical features

Clinical findings fall in to 2 categories:

1.Those due to increased ICT:

- Headache in up to 90% of pts- The headache is diffused and often progresses in severity

over days to weeks, resembling Migraine.- Minority of pts present with thunderclap headache - 25%.- There could be associated vomiting , papilledema , and visual disturbance.

Continuation of Clinical features

- Communicating hydrocephalus may develop (6.6%), due to derangement of Arachnoid granulation - Obstructive hydrocephalus is less common ;due to ventricular hemorrhage.

2.Those due to brain infarction / hemorrhage:

- Focal sign; Monoparesis/hemiparesis, Aphasia, cranial nerve palsy seizures- Encephalopathy; Confusion, psychiatric like presentation,- Drowsiness, stupor or coma

Continuation of Clinical features

3. Others:

- Fever - Elevated BP- Tachycardia/Bradycardia

Investigations Blood test:

- Baseline blood- Septic screen/Viral screen- DIC screen: D-dimer has high sensitivity (97.1%), and specificity of 91.2%- Clothing profile; PT/PTT- Screening for potential Prothrombotic conditions; TTP, HIT, etc- Lumbar Puncture; Elevated opening pressure in > 80%, Elevated cell counts (50%) and protein (35%) can be seen.

Continuation of Investigations

Imaging:

1. Non Invasive Imaging:

- CT : Has sensitivity of 75-100% and a specificity of 81-100% - MRI- Ultrasonography

2. Invasive Imaging:

- Cerebral Angiography - Direct Cerebral Venography.

Treatment Treatment of the underlying cause; if known

Seizures Control:

- Seizures are present in 37% of adults and 48% of children with diagnosis of DST

- Treatment is recommended after a single episode of seizure

- Prophylactic antiepileptic drugs may be harmful

Treatment Continued Control of intracranial hypertension:

- Severe raised intracranial pressure (RIP) may require therapeutic lumbar puncture - Medication like Acetazolamide could be use

- Neurosurgical interventions like shunting and Decompressive Hemicraniectomy may be offered if necessary

Treatment ContinuationAntithrombotic therapy:

1. Anticoagulation:

- Heparin or low molecular weight heparin, fallowed by Warfarin

- LMW heparin is preferred over Unfractionated heparin(UFH)

- Presence of ICH is not a contraindication

- Adjust dosage to achieve target INR of 2-3

Treatment Continuation- Anticoagulation last 3-6 month for Provoked DST , associated with transient risk factor e.g hormonal replacement therapy, pregnancy, etc

- Anticoagulate for 6 -12 month for Unprovoked CVT ; No known risk factor

- Indefinite anticoagulation is recommended for recurrent DST, DST with severe Thrombophilia or Venous thrombo embolism(VTE) after DST

Continuation of Treatment2. Thrombolysis : - European Federation of Neurological Societies guideline

recommends thrombolysis only if patient deteriorate despite adequate treatment

- Thrombolytic agents are given either systemically via vein, or directly into the clot during angiography.

- Commonest drug use are Urokinase and tissue plasminogen Activator (tp-A)

Treatment Continued- Mechanical Thrombolysis is done using Balloon assisted

Thrombectomy

- Surgical thrombectomy is rarely done

   Treatment Continuation Other treatments:

- Steroids are only use in case of vasogenic edema

- Steroid are not recommended, even in the presence of parenchymal brain lesions on CT/MRI, unless needed for another underlying fatal disease

- Antibiotics – indicated if there is associated infections

- Aspirin has no place in treatment of DST

PROGNOSIS About 80% of pts with DST recover completely or may have

minor residual symptoms or signs

It has 5% mortality in early phase, and about 10% mortality in late phase.

The main cause of death in early phase include Herniation of brain, Diffuse brain edema, Status epilepticus, Pulmonary embolism

Cause of death in later phase is generally due to underlying cause like cancer or CNS infection.

Predictors of poor prognosis

- Central nervous system infection- Any malignancy- Thrombosis of the deep venous system- Intra cranial Hemorrhage - Depressed consciousness- GCS < 9 on admission- Altered mental state - Age >37 years- Male gender

PROGNOSIS Dural Arteriovenous Fistula is another cause for poor

prognosis. It developed due to persistent dural sinus occlusion with increased venous pressure.

The fistula can close and cure if the sinus recanalizes. A preexisting fistula can be the cause of CVT.

Recanalization: Up to 85% DST reanalyze after 1 year

Recurrence: Rate of recurrence of DST is 2 -4 %, while the risk of recurrent venous thromboembolism in other locations ranges from 4 - 7 %

THANK YOU

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