CVST (Cerebral Venous Sinus Thrombosis): A Comprehensive Review

Cerebral venous sinus thrombosis (CVST) is a rare blood clot in one of your brain’s veins. Medicines and procedures can treat it. The outlook is good for those who get a prompt diagnosis and treatment. Prompt diagnosis and treatment give you the best chance of avoiding life-threatening complications. You’ll need to take medicine for at least three months after diagnosis, depending on the cause.

Introduction

Cerebral Venous Sinus Thrombosis (CVST) is an uncommon but potentially life-threatening cerebrovascular disorder characterised by the formation of a blood clot within the dural venous sinuses of the brain. These sinuses are responsible for draining blood from the brain parenchyma, and thrombosis impairs this process, leading to increased intracranial pressure and possible cerebral infarction or haemorrhage.

The condition can present with a wide spectrum of neurological symptoms, making early recognition and appropriate management critical. CVST has gained increased attention in recent years due to advances in neuroimaging and heightened awareness among clinicians.

Epidemiology

Incidence and Prevalence

CVST is relatively rare compared to arterial strokes, accounting for approximately 0.5-1% of all strokes. The incidence is estimated at 3-4 cases per 1 lakh population per year globally. However, in certain populations, such as young adults and children, CVST may comprise a higher proportion of stroke cases. Increased use of MRI and CT venography has led to improved detection rates in recent years.

Demographic Patterns

CVST affects a wide age range, but it is most commonly observed in young adults, particularly women aged 20-40 years. The female predominance is attributed to gender-specific risk factors such as pregnancy, puerperium, and oral contraceptive use. Paediatric cases, although less frequent, are important, especially in neonates and infants, often linked to infection or dehydration. There are no significant racial differences in the incidence of CVST, but certain geographical regions with higher prevalence of prothrombotic conditions may report increased cases.

Risk Factors

Genetic Contributors

Hereditary thrombophilias are significant risk factors for CVST. These include deficiencies of protein C, protein S, and antithrombin III, as well as mutations such as Factor V Leiden and prothrombin G20210A. Individuals with these genetic predispositions have a heightened tendency to develop venous thromboembolism, including CVST.

Acquired Risk Factors

Several acquired factors contribute to the development of CVST:

• Pregnancy and Puerperium: The hypercoagulable state during pregnancy and the postpartum period increases CVST risk, especially in the first three weeks after delivery.
• Oral Contraceptives and Hormone Replacement Therapy: Oestrogen-containing preparations are associated with increased thrombotic risk.
• Malignancy: Certain cancers, particularly haematological malignancies, promote a prothrombotic milieu.
• Infections: Local infections such as sinusitis, mastoiditis, and systemic infections like sepsis can precipitate CVST.
• Trauma and Surgery: Head injury and neurosurgical interventions may disrupt venous structures and predispose to thrombosis.
• Systemic Diseases: Conditions like systemic lupus erythematosus (SLE), antiphospholipid syndrome, and nephrotic syndrome are associated with increased risk.

Environmental and Lifestyle Factors

Dehydration, especially in children and older adults, can precipitate CVST by increasing blood viscosity. High altitude exposure, prolonged immobilisation, and certain medications (e.g., steroids) also contribute to risk.

Pathophysiology

Mechanisms of Thrombosis

CVST involves the formation of a thrombus within the cerebral venous sinuses, most commonly affecting the superior sagittal sinus, transverse sinuses, and sigmoid sinuses. The underlying mechanism is often a combination of endothelial injury, stasis of blood flow, and hypercoagulability (Virchow’s triad). The thrombus obstructs venous drainage, leading to increased venous pressure, reduced cerebrospinal fluid absorption, and raised intracranial pressure.

Affected Sinuses and Consequences

The location of the thrombus determines the clinical manifestations:

• Superior Sagittal Sinus: Most commonly affected; associated with headache, seizures, and bilateral neurological deficits.
• Transverse and Sigmoid Sinuses: Can lead to focal deficits, cranial nerve palsies, and papilloedema.
• Cavernous Sinus: Associated with ophthalmoplegia, proptosis, and facial pain due to involvement of cranial nerves III, IV, V, and VI.

Venous congestion may result in venous infarction, which is often haemorrhagic. This distinguishes CVST from arterial strokes, where infarctions are typically non-haemorrhagic.

Clinical Presentation

Common Symptoms

CVST presents with a wide range of symptoms, often making diagnosis challenging. The most frequent clinical features include:

• Headache: The most common presenting symptom, occurring in over 80% of cases. The headache is usually diffuse, progressive, and may resemble migraine or tension-type headache.
• Seizures: Present in up to 40% of patients, including focal, generalised, or status epilepticus.
• Focal Neurological Deficits: Weakness, sensory loss, aphasia, or visual disturbances depending on the site of thrombosis.
• Papilloedema: Due to increased intracranial pressure, leading to visual impairment if untreated.

Atypical Symptoms and Progression

Some patients may present atypically, with symptoms such as altered mental status, coma, or isolated cranial nerve palsies. In children, symptoms like irritability, vomiting, and lethargy predominate. The progression of CVST is variable; it may be acute, subacute, or chronic, with some patients deteriorating rapidly while others have a more indolent course.

Diagnosis

Imaging Modalities

Neuroimaging is the cornerstone of CVST diagnosis. The following modalities are commonly employed:

• Magnetic Resonance Imaging (MRI) and Magnetic Resonance Venography (MRV): MRI is highly sensitive for detecting parenchymal lesions (infarcts, haemorrhage), while MRV visualises venous sinus occlusion.
• Computed Tomography (CT) and CT Venography (CTV): CT is useful for initial assessment, especially in emergency settings. CTV can delineate venous anatomy and identify thrombi.
• Digital Subtraction Angiography (DSA): Previously the gold standard, now reserved for complex cases or when non-invasive imaging is inconclusive.

Laboratory Tests

Blood investigations support diagnosis and management:

• Coagulation Profile: Prothrombin time, activated partial thromboplastin time, and D-dimer levels may be altered.
• Thrombophilia Workup: Includes screening for inherited and acquired coagulation disorders.
• Inflammatory Markers: Raised in cases of infection-associated CVST.

Differential Diagnosis

CVST must be differentiated from other causes of headache and neurological deficits, such as migraine, intracerebral haemorrhage, arterial stroke, meningitis, and idiopathic intracranial hypertension. A high index of suspicion is essential, especially in young patients with atypical stroke presentations.

Management

Acute Treatment

The primary goals in CVST management are to prevent thrombus extension, facilitate recanalisation, and manage complications:

• Anticoagulation: Low molecular weight heparin (LMWH) or unfractionated heparin is initiated even in the presence of haemorrhagic infarction, unless contraindicated. This is followed by oral anticoagulants (warfarin, direct oral anticoagulants) for 3-12 months depending on underlying risk factors.
• Thrombolysis and Endovascular Therapy: Considered in selected patients with clinical deterioration despite anticoagulation, or extensive thrombosis. Catheter-directed thrombolysis or mechanical thrombectomy may be used in specialised centres.
• Management of Raised Intracranial Pressure: Includes head elevation, osmotic agents (mannitol), and in refractory cases, decompressive surgery.

Long-term Therapy and Supportive Care

Long-term management includes:

• Continuation of Anticoagulation: Duration is tailored based on risk factors and recurrence risk.
• Treatment of Underlying Causes: Infections, malignancy, or autoimmune diseases should be addressed concurrently.
• Rehabilitation: Physiotherapy, occupational therapy, and neuropsychological support for residual deficits.
• Seizure Prophylaxis: Antiepileptic drugs may be needed in patients with seizures.

Prognosis

Outcomes and Recovery Rates

The prognosis of CVST has improved significantly with early diagnosis and effective treatment. Mortality rates have declined to less than 10% in recent studies. Most patients achieve good functional recovery, with 80-90% regaining independence. Poor prognosis is associated with advanced age, coma at presentation, extensive thrombosis, and underlying malignancy.

Factors Affecting Prognosis

Key factors influencing outcomes include:

• Extent of Thrombosis: Involvement of multiple sinuses increases risk of complications.
• Presence of Parenchymal Lesions: Haemorrhagic infarcts and cerebral oedema worsen outcomes.
• Delay in Treatment: Early initiation of anticoagulation correlates with better recovery.
• Comorbid Conditions: Underlying cancer, infection, or autoimmune disease may adversely affect prognosis.

Complications

Neurological Sequelae

CVST can result in persistent neurological deficits such as hemiparesis, aphasia, visual impairment, and cognitive dysfunction. Some patients may develop chronic headaches or epilepsy.

Recurrence and Other Risks

Recurrence rates are relatively low (2-7%), but higher in patients with persistent risk factors (thrombophilia, malignancy). Other complications include hydrocephalus, cerebral herniation, and death in severe cases. Long-term surveillance is recommended for high-risk individuals.

Key Takeaways

Recent advances include new anticoagulants, endovascular therapies, and improved risk stratification.

• CVST is a rare cerebrovascular disorder with diverse clinical manifestations.
• Young women, especially during pregnancy or postpartum, are at increased risk.
• Neuroimaging is essential for diagnosis; MRI/MRV is the preferred modality.
• Anticoagulation remains the mainstay of treatment, even in cases with haemorrhagic infarction.
• Prognosis is generally favourable with early diagnosis and management, but complications can be serious.

Nursing Care of Patients with Cerebral Venous Sinus Thrombosis (CVST)

Nurses play a pivotal role in the identification, acute management, and ongoing care of patients with CVST, requiring a multidisciplinary approach to ensure the best possible outcomes.

Assessment and Initial Management

1. Comprehensive Assessment

• Monitor vital signs closely, with special attention to blood pressure, pulse, respiratory rate, and temperature.
• Perform frequent neurological assessments using the Glasgow Coma Scale (GCS) and by monitoring for signs of increased intracranial pressure (ICP), including headache, vomiting, changes in consciousness, and pupillary changes.
• Assess for the presence of focal neurological deficits such as weakness, speech disturbances, or visual changes.
• Create a detailed history, including risk factors (recent pregnancy, postpartum period, oral contraceptive use, coagulation disorders, cancer, recent infections, dehydration, trauma, prothrombotic states).
• Monitor laboratory investigations (CBC, coagulation profile, D-dimer, renal and liver functions) and imaging (MRI/MRV) as prescribed.

2. Immediate Interventions

• Ensure airway patency and support breathing and circulation as needed.
• Initiate seizure precautions, as seizures are common in CVST.
• Establish intravenous access for medication administration and fluid management.
• Begin anticoagulation therapy (commonly low molecular weight heparin or unfractionated heparin) as prescribed and monitor for bleeding complications.
• Prepare for possible transfer to a higher level of care (e.g., intensive care unit) depending on patient acuity.

Ongoing Nursing Care

1. Neurological Monitoring

• Perform regular neurological checks to detect early signs of deterioration, including changes in consciousness, orientation, limb strength, and cranial nerve function.
• Monitor for the development or progression of headaches, visual changes, or papilledema.
• Promptly report any new or worsening neurological symptoms to the medical team.

2. Monitoring and Managing Intracranial Pressure

• Position the patient with the head of the bed elevated at 30 degrees to facilitate venous drainage, unless contraindicated.
• Avoid activities or positions that may increase ICP, such as excessive suctioning, Valsalva maneuvers, or head-down positioning.
• Monitor for signs of raised ICP (restlessness, confusion, hypertension, bradycardia, irregular respirations—Cushing’s triad), and take immediate action if such signs are present.

3. Seizure Precautions

• Pad side rails and keep the bed in a low position with call bell within reach.
• Maintain ready access to emergency medications (e.g., benzodiazepines) as prescribed.
• Observe for and promptly document any seizure activity, including duration, type, and post-ictal state.
• Educate patient and family about aura symptoms and seizure first aid.

4. Administration and Monitoring of Anticoagulation Therapy

• Administer anticoagulants as prescribed and monitor for adverse effects, particularly bleeding (bleeding gums, hematuria, melena, petechiae).
• Monitor laboratory parameters (aPTT, PT/INR, platelet counts) regularly to ensure therapeutic levels and minimize risks.
• Educate patients and caregivers about the importance of medication adherence and signs of bleeding to watch for at home.

5. Pain Management

• Assess pain using appropriate pain scales and provide analgesics as needed, while avoiding medications that may increase ICP.
• Encourage non-pharmacological pain relief measures such as a calm environment, dim lighting, and cold compresses if appropriate.
• Monitor response to pain interventions and modify the care plan accordingly.

6. Fluid and Electrolyte Balance

• Monitor fluid intake and output vigilantly to prevent dehydration, especially in patients with vomiting or altered consciousness.
• Administer intravenous fluids as prescribed, taking care not to overload the circulation and contribute to increased intracranial pressure.
• Monitor serum electrolytes and correct imbalances promptly to reduce the risk of neurological complications.

7. Prevention of Complications

• Implement pressure injury prevention strategies: frequent repositioning, use of pressure-relieving devices, and meticulous skin care.
• Prevent deep vein thrombosis by encouraging active or passive limb exercises as tolerated, and use compression stockings if indicated.
• Monitor for hospital-acquired infections: maintain strict asepsis for invasive lines, perform regular oral care, and encourage respiratory exercises to prevent pneumonia.

8. Nutritional Support

• Assess swallowing ability before oral intake; if impaired, use appropriate enteral feeding methods.
• Collaborate with dietitians to provide adequate caloric and nutrient intake, tailored to the patient’s needs and medical condition.
• Monitor for signs of malnutrition or aspiration.

9. Psychosocial Support and Patient/Family Education

• Provide emotional support and reassurance to patients and families, who may be distressed by the acute and unpredictable nature of CVST.
• Offer clear explanations about the disease process, expected course, and treatment strategies.
• Involve family members in the care process and educate them about recognizing early warning signs of complications at home.
• Refer to psychological or social services as needed.

Discharge Planning and Rehabilitation

A multidisciplinary approach is vital for the safe transition from hospital to home or rehabilitation. Nurses play a central role in coordinating care, liaising with physical therapists, occupational therapists, speech-language pathologists, and social workers.

• Assess the patient’s functional status and need for assistive devices or home modifications.
• Arrange for follow-up appointments (neurology, hematology, rehabilitation).
• Educate regarding medication management, side effects, and the importance of regular monitoring.
• Provide written instructions on diet, activity restrictions, and when to seek immediate medical attention (e.g., sudden headache, seizures, weakness, speech difficulties).
• Encourage gradual resumption of activities as tolerated, with attention to safety and energy conservation.
• Address questions related to anticoagulation therapy, potential interactions, and bleeding risks.

Special Considerations

• Pediatric Patients: CVST may occur in children, often associated with dehydration, infection, or congenital conditions. Nursing care principles remain similar but require age-appropriate interventions and family involvement.
• Pregnant/Postpartum Patients: Women during pregnancy or the puerperium are at increased risk. Extra care is taken to monitor for complications and coordinate with obstetric teams.
• Patients with Comorbidities: Comprehensive care plans should be developed in collaboration with specialists managing underlying conditions such as malignancy, autoimmune diseases, or chronic infections.

REFERENCES

1. American Heart Association. A Patient’s Guide to Taking Warfarin. https://www.heart.org/en/health-topics/arrhythmia/prevention–treatment-of-arrhythmia/a-patients-guide-to-taking-warfarin.
2. Al-Jehani HM. Cerebral Venous Sinus Thrombosis. Saudi J Med Med Sci. 2019 Sep-Dec;7(3):135-136. doi: 10.4103/sjmms.sjmms_281_19. Epub 2019 Aug 28. PMID: 31543732; PMCID: PMC6734738.
3. Idiculla PS, Gurala D, Palanisamy M, et al. Cerebral Venous Thrombosis: A Comprehensive Review. https://pubmed.ncbi.nlm.nih.gov/32877892/. Eur Neurol. 2020;83(4):369-379.
4. National Blood Clot Alliance. Treatment of Thrombosis. https://www.stoptheclot.org/news/treatment-of-thrombosis/.
5. Perry RJ, Tamborska A, Singh B, et al. Cerebral venous thrombosis after vaccination against COVID-19 in the UK: a multicentre cohort stud. https://pubmed.ncbi.nlm.nih.gov/34370972/. Lancet. 2021 Sep 25;398(10306):1147-1156.
6. Chatterjee S, Sharma CB, Guria RT, Dubey S, J Lavie C. Cerebral venous sinus thrombosis-A primer for emergency physician. J Family Med Prim Care. 2020 Apr 30;9(4):2107-2110. doi: 10.4103/jfmpc.jfmpc_192_20. PMID: 32670974; PMCID: PMC7346905.

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