Dural Arteriovenous Fistulas

An improper connection between an artery and a vein in the tough covering over the brain or spinal cord is known as a dural arteriovenous fistula (dAVF) (dura mater). Arteriovenous fistulas (abnormal connections between arteries and veins) can develop in the brain, spinal cord, or other parts of your body in this uncommon illness.

Children aren't more likely to acquire a dAVF just because their parent has one; instead, dAVFs normally develop later in life (between 50 and 60 years of age), and they aren't usually genetically passed on.

Although certain dAVFs have recognized origins, it's believed that dAVFs involving major brain veins typically develop as a result of a venous sinus in the brain being congested or blocked. Venous sinuses are the blood vessels that carry circulating blood from the brain back to the heart.

Endovascular surgery or stereotactic radiosurgery to limit blood supply to the dAVF is typically used as a treatment for dAVF. Otherwise, the dAVF may need to be disconnected or removed by surgery.

Dural Arteriovenous Fistulas: Causes

Although some are the consequence of known causes such as severe head injury (or traumatic AV fistula), infection, prior brain surgery, venous thrombosis, or malignancies, the majority of dural arteriovenous fistulas are unclear in their origin.

According to the majority of experts, one of the brain's venous sinuses, which carry circulating blood from the brain back to the heart, gradually narrows or becomes blocked in most cases when dAVFs involving the bigger brain veins occur.

Dural Arteriovenous Fistulas: Symptoms

Some individuals with dAVFs might not exhibit any symptoms. Nonetheless, evident symptoms might be classified as either aggressive or benign. Intracerebral hemorrhage or neurological consequences of non-hemorrhagic neurological impairments can also cause aggressive dAVF symptoms (NHNDs).

According to the location and amount of the hemorrhage, bleeding in the brain frequently results in an acute headache with varied degrees of neurological impairment. An NHND, in contrast, frequently manifests symptoms specific to its site and normally develops more gradually over days to weeks.

These aggressive signs may appear as −

• Falls and difficulty walking

• Seizures

• Difficulties with speech or language

• A facial ache

• Dementia

• Parkinsonism

• Coordinating problems

• Burning or stinging feelings

• Weakness

• Apathy

• Failing to flourish

• The pressure-related symptoms of headaches, nausea, and vomiting.

Hearing problems, such as pulsatile tinnitus, and a bruit behind the ear, are examples of additional dAVF symptoms. Additional signs include eyesight issues like −

• Degradation of vision

• Eye swell

• The lining of the eyes swelling

• Ocular palsies

• Cleft palate syndrome.

• Rarely, venous hypertension can cause progressive dementia.

When to Visit a Doctor?

If you have any signs or symptoms that appear strange or alarm you, schedule a doctor's appointment. If you encounter any seizure symptoms or signs that might be a sign of a brain hemorrhage, such as −

• An unexpectedly bad headache

• Nausea

• Vomiting

• On one side of the body, there is weakness or numbness

• Speaking of interpreting speech with difficulty

• Absence of vision

• Dual perception

• Challenges with balance

Dural Arteriovenous Fistulas: Risk Factors

Those who are genetically susceptible to venous blood clots are among the risk factors for dAVFs (vein thrombosis). This might involve irregularities in blood clotting, which could raise the possibility of venous sinus occlusion or obstruction.

Those with dAVFs are often affected in their late middle years (roughly from 50 to 60 years old). Nevertheless, dAVFs can also happen to younger people, such as children. Current research does indicate that the emergence of dAVFs may potentially be linked to benign meningeal tumors.

Dural Arteriovenous Fistulas: Diagnosis

The diagnosis of the dural arteriovenous fistulas is mainly done based on history and some of the tests may be required for confirmation and to rule out underlying causes

• First imaging. Cross-sectional images from magnetic resonance imaging (MRI) and non-contrast head computer tomography (CT) are frequently used in initial assessment (MRI).

• Head CT scans. These tests can detect both real bleeding—which may be brought on by a dAVF but take place elsewhere in the brain's venous system—and fluid accumulation brought on by increased cortical vein blood pressure.

• MRIs. With the use of these pictures, a dAVF's shape and size may be established, along with any microhemorrhages (extremely minute bleeding areas) and the influence of any unusual blood vessel structures connected to the fistula itself.

• Angiography. The most accurate and conclusive method for diagnosing dAVF is still catheter-based cerebral angiography, commonly known as digital subtraction angiography.

Dural Arteriovenous Fistulas: Treatment

The treatment is based on the severity of the symptoms. Your doctor may advise conservative or surgical treatment.

Surgical Treatment

Surgical treatment may be required in severe cases which include −

• Endovascular techniques. With the use of X-ray imaging, your doctor may perform an endovascular treatment in which they put a long, thin tube (catheter) into a blood vessel in your leg or groin and thread it through blood vessels to the Dural arteriovenous fistula. To block the aberrant blood vessel connection, your doctor inserts the catheter into the blood vessel that supplies the dAVF and releases coils or a glue-like material.

• Stereoscopic radiosurgery. Your doctor will perform stereotactic radiosurgery to block the aberrant blood vessel link using finely focused radiation. The dAVF is destroyed by the fistula's blood channels closing shut due to the strong radiation dosage administered to it.

• The linear accelerator (LINAC), gamma knife, and proton beam treatment are among the several technological platforms employed in dAVF stereotactic radiosurgery.

• Surgery for dAVF. You could require dAVF surgery if stereotactic radiosurgery or an endovascular technique are not viable choices for you. To reconnect the dAVF, stop the blood flow, and eliminate the fistula, surgery may be performed.

Dural Arteriovenous Fistulas: Prevention

There is no way of preventing dAVF

Conclusion

Although dural arteriovenous fistulas are uncommon, there are no set standards that practitioners must adhere to. Because the condition's clinical symptoms are varied, a high index of suspicion is required for the diagnosis. To establish an early diagnosis and administer the proper therapy, a team of healthcare specialists working together in an integrated manner is advised. The treatment regimen and monitoring can be coordinated by the neurologist, neurosurgeon, interventional radiologist, and critical care physician.

The nurse is essential for overseeing the neurological examination after treatment and assisting with ambulation and nutrition. Informing the patient and family about the illness and any possible side effects of therapy is another responsibility of the nurse. The pharmacist also makes that the patient continues to take his or her medications as prescribed and maintains blood pressure management.