Aqueductal stenosis

• 

  Diagram of the ventricular system of the brain

• 

  Hydrocephalic brain with enlarged ventricles

• 

  Third ventricle of the brain

• 

  Fourth ventricle of the brain

Aqueductal Stenosis

Aqueductal stenosis is a condition characterized by the narrowing of the cerebral aqueduct, also known as the aqueduct of Sylvius, which is a channel that connects the third and fourth ventricles in the brain. This narrowing can lead to the obstruction of cerebrospinal fluid (CSF) flow, resulting in a condition known as hydrocephalus.

Anatomy and Physiology

The cerebral aqueduct is a slender canal located in the midbrain, part of the brainstem. It is approximately 1.5 mm in diameter and serves as a conduit for CSF to flow from the third ventricle, located in the diencephalon, to the fourth ventricle, situated between the pons and the cerebellum. The proper functioning of the cerebral aqueduct is crucial for maintaining normal CSF circulation and intracranial pressure.

Pathophysiology

Aqueductal stenosis can be congenital or acquired. Congenital aqueductal stenosis is often due to developmental anomalies, such as aqueductal webs or gliosis. Acquired causes include tumors, infections, or hemorrhage that lead to scarring and narrowing of the aqueduct.

The obstruction of CSF flow results in increased pressure in the ventricles proximal to the obstruction, leading to ventricular dilation and hydrocephalus. This can cause symptoms such as headache, nausea, vomiting, and papilledema. In infants, it may lead to an increase in head size and bulging fontanelles.

Diagnosis

Diagnosis of aqueductal stenosis is typically made using neuroimaging techniques. Magnetic resonance imaging (MRI) is the preferred method as it provides detailed images of the brain's ventricular system and can identify the site and cause of the obstruction. Computed tomography (CT) scans may also be used, particularly in emergency settings.

Treatment

The primary treatment for aqueductal stenosis is surgical intervention to restore normal CSF flow. The most common procedure is the placement of a ventriculoperitoneal shunt, which diverts excess CSF from the ventricles to the peritoneal cavity, where it can be absorbed. Another surgical option is endoscopic third ventriculostomy (ETV), which creates an opening in the floor of the third ventricle to allow CSF to bypass the obstruction.

Prognosis

The prognosis for individuals with aqueductal stenosis depends on the underlying cause, the severity of the condition, and the success of the treatment. Early diagnosis and intervention are crucial for preventing long-term complications such as cognitive impairment and motor deficits.

Related Pages

• Hydrocephalus
• Cerebrospinal fluid
• Ventriculoperitoneal shunt
• Endoscopic third ventriculostomy
• Brainstem

edit 

WikiMD neurology

External links

• Comprehensive information from the National Institute of health.
  

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z