Cerebral Venous Thrombosis: The Stroke that Evades Diagnosis

An illustration depicting a blood clot (thrombus) obstructing a blood vessel.

What is Cerebral Venous Thrombosis? How is it different?

In 2021 alone, 7.3 million people died because of stroke (Feigin et al., 2024). As of 2025, stroke remains the second leading cause of death among non-communicable diseases (Feigin et al., 2025). But not all types of strokes present equally.

When people think of a stroke, they often think of the F.A.S.T acronym developed by the American Stroke Association: face drooping, arm weakness, speech difficulty, time to call 911. These are indeed the most common symptoms, but different types manifest uniquely.

Unlike typical strokes that occur in cerebral arteries, cerebral venous thrombosis (CVT) is a direct result of venous obstruction. CVT accounts for only 0.5% to 3% of strokes, making it relatively rare (Uminski et al., 2026). It involves the formation of a blood clot, known as a thrombus, within the veins of the brain. This venous obstruction, when severe enough, can cause an increase in intracranial pressure, brain damage, and potentially result in a hemorrhage (Morais & Aguiar de Sousa, 2025).

Symptom Presentation of CVT

In most cases, the chief complaint of patients with CVT is a severe headache. However, the description and location of the pain that patients provide seems to be extremely varied with no pattern (Mehta et al., 2019). In fact, CVT as a condition is considered heterogenous, meaning that its causes and symptoms can vary immensely from person to person. This makes diagnosis extremely difficult, however, when suspicion of CVT is raised, there are a couple commonplace tests.

Firstly, the patient’s biochemical workup will often include a D-dimer assay. D-dimer is associated with the breakdown of fibrin (fibrinolysis), which is one pathway which the body uses to dissolve blood clots (Johnson et al., 2019). A positive result returned is a supporting sign for CVT, however, approximately 10% of cases do not present with a positive D-dimer assay (Morais & Aguiar de Sousa, 2025).

Often, the final diagnosis is based on some form of cerebral and vascular imaging. Most commonly, the thrombus can be observed using CT venography or an MRI. In some cases, an MRI will also show parenchymal brain lesions that may result from the thrombosis in about half of the cases (Morais & Aguiar de Sousa, 2025).

An illustration/model depicting a blood clot (thrombus).

Risk Factors for CVT

While several potent risk factors are known, it’s important to note that up to 20% of cases are of an unknown cause (Uminski et al., 2026). Thrombogenesis is much more likely in the presence of inflammation or pro-inflammatory stimuli. Cancer, head trauma, neurosurgery, and other forms of cerebral injury are all associated with increased risk of CVT. More chronic risk factors such as obesity and anemia have also been shown to be a risk factor (Morais & Aguiar de Sousa, 2025; Potere et al., 2023).

Interestingly, COVID-19 has been shown to result in CVT in certain rare cases. The mechanism isn’t fully understood, but coagulopathy is associated with COVID-19 infection (Axelerad et al., 2023). Coagulopathy refers to a condition in which the blood clots abnormally, including both hypercoagulability and impaired clot formation.

Hypercoagulability is one of the three components of Virchow’s Triad, which describes three conditions which disrupt the balance between blood clot formation and breakdown (Morais & Aguiar de Sousa, 2025). When these three conditions align, it puts the person at risk of developing vascular thrombosis: blood hypercoagulability, disruption of blood flow, and vessel wall injury (Kushner et al., 2024).

Long-term Outcomes

Compared the arterial stroke, patient outcomes are relatively favourable, with about 80% of cases recovering without major disability. However, many of these cases do suffer from some form of chronic symptom. Most commonly, these can manifest as headaches, difficulty concentrating, and the onset of mood disorders (Zuurbier & Coutinho, 2016).

The mortality rate of CVT patients in the clinical environment is about 4%, and in the long-term, that number rises to 8-10%. While mortality rates are relatively favourable, it’s approximated that about 20%-40% of individuals will not be able to return to their workplace, and about 10% of patients have been found to experience seizures post-CVT (Morais & Aguiar de Sousa, 2025).

But it’s not all bad news. In recent years, despite its rarity, CVT has been getting more attention and research surrounding it continues to increase. In terms of treatment, a large cohort study determined that Direct Oral Anticoagulants are a safer option for CVT patients, with a lower risk of intracranial hemorrhage in comparison to the previous standard drug Warfarin (Yaghi et al., 2022). As the medical community’s knowledge continues to grow, the odds of successful treatment will only improve.

Summary and Conclusion

Cerebral Venous Thrombosis is the leading cause of strokes in younger populations, despite being a relatively rare type of stroke. Symptoms can vary massively from patient to patient, but often most patients present with a severe headache. Pro-inflammatory responses can be a trigger for CVT, but up to 20% of cases do not have a known cause. COVID-19 has also been shown to trigger CVT in certain cases. The prognosis is favourable, with only about 4% mortality in the clinical care setting, and 8%-10% long-term. While most patients will recover without major disability, chronic symptoms can remain. Particularly headache, mood disorders, issues with concentration, and in rarer cases, seizures. But as research continues to progress on CVT and its causes, the efficacy of treatments will continue to grow.

References

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