The use of ocular ultrasound can quickly and safely identify children with cerebral drainage tube failure in the emergency department.
- A ventricular bypass involves installing a small tube inside the ventricle to drain fluid out of the brain.
- Children with it typically undergo multiple CT scans and MRIs per year, exposing them to excessive radiation and sedation.
- The change in optic nerve diameter helped identify shunt dysfunction.
A ventricular shunt is a small, surgically implanted plastic tube that drains excess fluid. According to the National Cancer Institute, fluid is drained through this drain, either directly through the skull (external diversion) or into another part of the body, often the abdomen (internal diversion), which relieves pressure on the brain. Children receive ventricular leads for hydrocephalus, a condition in which brain fluid does not drain or reabsorb properly due to brain hemorrhages, tumors, or other causes.
Ventricular bypass: symptoms are often nonspecific
“Nearly 30% of ventricular leads malfunction, either break, shift or become blocked, within two years of their placement, and 5% of them fail each year thereafter, according to the experts”, said researchers from the Hospital for Sick Children in Toronto (Canada). When a patient goes to the emergency room for potential shunt failure, their symptoms are often nonspecific, including headache, vomiting, and fatigue. Lead failure is life-threatening, and children with it typically undergo multiple CT scans and MRIs per year, exposing them to excessive radiation and sedation. A buildup of fluid causes swelling of the optic nerve sheath, which can be measured using an ocular ultrasound.
53% of young participants had congenital hydrocephalus
In a recent study, the Canadian team wanted to know if changing the diameter of the optic nerve when a patient has symptoms and when they are healthy could help determine if a bypass is blocked. For the purposes of their work, she examined 76 pairs of scans which were carried out on 58 asymptomatic children who had undergone a bypass. The average age of young patients was approximately 7 years and 65.8% were boys. According to the data, 53% of children had congenital hydrocephalus, 21% had a tumor, 53% were admitted to hospital and 21% went to the operating room.
Changing optic nerve diameter to identify ventricular bypass failure
The results, which were presented at the congress of the Pediatric Academic Societies 2024 taking place from May 2 to 6 in Toronto, change in optic nerve diameter was significantly associated with shunt dysfunction, whereas change in optic disc elevation was not. The change in optic nerve diameter was also linked to increased ventricular size, periventricular interstitial edema, or effacement of cortical sulci. “The absence of change in optic nerve head elevation in shunted patients should not provide undue reassurance. Further research is needed to determine whether change in optic nerve diameter contributes positively to the prediction rules clinic of bypass failure”concluded the authors.
