What is Aqueductal Stenosis?

Aqueductal stenosis is a narrowing of one of the channels in the brain that acts as a conduit for cerebrospinal fluid, the fluid that bathes the brain and provides protectant properties. In a person with aqueductal stenosis, the free flow of the fluid is restricted and the patient can develop hydrocephalus, a buildup of cerebrospinal fluid that leads to neurological complications over time. One of the most common causes of congenital hydrocephalus, where someone is born with fluid on the brain, is aqueductal stenosis.

This condition involves the cerebral aqueduct, also known as the aqueductal of Sylvius. This particular channel for cerebrospinal fluid runs between the third and fourth ventricles. When the aqueduct narrows, it limits the flow of cerebrospinal fluid, and the fluid can begin to back up and accumulate. Over time, this can cause swelling that will lead to brain damage by putting pressure on brain cells. In infants, it may cause distortions in skull shape because the developing skull expands to accommodate the excess fluid.

In congenital aqueductal stenosis, something goes wrong during the development of the brain and this channel is narrow or not fully formed, impairing the circulation of cerebrospinal fluid in the fetus. In acquired cases, someone develops a condition such as an infection, inflammation, or neurological disease that damages the aqueduct and causes it to narrow. This leads to obstructive hydrocephalus, where cerebrospinal fluid builds up because it has nowhere to go.

People with aqueductal stenosis usually experience headaches that may worsen over time and do not resolve with rest or medications. Nausea and vomiting can also develop as a result of the pressure on the brain. Altered level of consciousness is another symptom that tends to occur as the hydrocephalus persists untreated. Generally, any time people experience a combination of headaches, mood changes, and nausea, it can be a warning sign that there is a neurological problem.

Medical imaging studies of the brain will be used to determine what is going on inside and to determine how much damage has occurred, if any. The recommended treatment is usually installation of a shunt to allow the excess cerebrospinal fluid to safely drain. If a tumor is involved, surgery to remove the tumor is recommended and the removal of the growth should resolve the hydrocephalus. Other treatment options can include radiation treatment of tumors that are not considered operable. These treatments are performed by a neurosurgeon, a physician who specializes in performing surgery on the brain.