When a Blood Clot Causes a Stroke: DVT and CVST Explained
Posted on in Medical Negligence
When most people think about a stroke, they imagine a blood clot blocking an artery supplying the brain. However, strokes can also occur because of other types of blood clots, some of which are rare and can be difficult to recognise.
Prompt diagnosis and treatment of thrombosis can often prevent serious complications. Unfortunately, where warning signs are overlooked, or investigations are delayed, the consequences can be life-changing.
How can thrombosis lead to a stroke?
There are two important ways that blood clots may contribute to stroke.
- Deep Vein Thrombosis (DVT)
A DVT is a blood clot that usually forms in a vein in the leg or pelvis. The greatest concern is that part of the clot may travel to the lungs, causing a pulmonary embolism. In rare cases, where a person has an abnormal opening between the chambers of the heart (known as a patent foramen ovale), a clot can pass into the arterial circulation and travel to the brain, causing what is known as a paradoxical embolic stroke.
- Cerebral Venous Sinus Thrombosis (CVST)
CVST is a rare condition in which a blood clot forms within the veins that drain blood away from the brain. Instead of reducing blood flow into the brain, the blockage prevents blood from draining properly, increasing pressure within the skull and potentially causing bleeding or damage to brain tissue.
Although uncommon, CVST can affect adults of any age and can also occur in newborn babies.
When can things go wrong?
The symptoms of thrombosis are not always straightforward.
A DVT may cause:
- Swelling of one leg.
- Pain or tenderness in the calf.
- Warmth or redness of the skin.
CVST may present with:
- A severe or persistent headache.
- Blurred or double vision.
- Vomiting.
- Seizures.
- Weakness or numbness affecting one side of the body.
- Difficulty speaking or confusion.
Because these symptoms can resemble migraine, viral illness or other less serious conditions, diagnosis may be delayed.
Appropriate assessment may include blood tests, ultrasound scans, CT or MRI brain imaging and specialised venography.
Early treatment with anticoagulant medication can often prevent further clot formation and reduce the risk of permanent brain injury or death.
Example Case Study
Sarah, a 34-year-old marketing executive, attended the Emergency Department complaining of a worsening headache that had persisted for several days. She had recently started taking the combined oral contraceptive pill and described episodes of blurred vision and vomiting.
She was diagnosed with migraine and discharged home without brain imaging.
Over the following 48 hours, Sarah developed weakness down her left side before collapsing at home. She was rushed back to hospital, where MRI imaging confirmed cerebral venous sinus thrombosis.
Although anticoagulant treatment was started immediately, Sarah was left with permanent weakness affecting her left arm and ongoing epilepsy.
Had Sarah’s symptoms prompted urgent neuroimaging at her first attendance given the risk factors of the combined oral contraceptive pill. Earlier diagnosis and treatment would have prevented significant brain injury.
Could this amount to medical negligence?
Thrombosis-related strokes are often uncommon and can be challenging to diagnose. A missed diagnosis does not automatically mean that medical care was negligent.
However, concerns may arise where healthcare professionals fail to:
- Recognise symptoms suggesting thrombosis.
- Take account of important risk factors.
- Arrange appropriate investigations.
- Refer patients urgently where specialist assessment is required.
- Start anticoagulant treatment when clinically indicated.
To establish a medical negligence claim, it is generally necessary to show that the standard of care fell below what would reasonably be expected and that earlier diagnosis or treatment would probably have prevented the stroke or reduced the severity of the resulting injury.
Early recognition can make all the difference
Whether affecting an adult, child or a newborn baby, thrombosis involving the brain is a medical emergency.
Recognising the warning signs, carrying out timely investigations and starting appropriate treatment can significantly improve outcomes.
For families whose lives have been affected by a thrombosis-related stroke, understanding whether opportunities to diagnose and treat the condition were missed can be an important step towards obtaining answers and accountability.
If you or a family member has been affected by medical negligence, contact our specialist medical negligence lawyers; we will help you to recover appropriate compensation and secure your future.