Recent medical advances have led to longer survival of chronically ill children, often referred to as the “high-tech” child. As a result, emergency departments are seeing these medically-fragile patients more frequently. Patients with a cerebrospinal fluid (CSF) shunt, a tracheostomy tube, the need for chronic oxygen therapy, invasive or noninvasive ventilatory support, chronic dialysis, a gastrostomy tube (GT), or an indwelling central venous catheter (CVC), among others, are defined as technology dependent. Review of available previous medical records and contacting the medical home or primary care physician early in the patient’s course can provide information that may help guide the decision-making process.
CEREBROSPINAL FLUID SHUNTS
Cerebrospinal fluid (CSF) is made and absorbed by the body at a constant rate. Mainly made at the choroid plexus, it flows from the lateral ventricles into the third and fourth ventricles where it passes to the subarachnoid space. It is reabsorbed through one-way valve into the venous system. When excess fluid is present either from overproduction, blockage of circulation, or diminished absorption, hydrocephalus occurs. These patients become symptomatic when this increase in CSF increases intracranial pressure (ICP). The most common neurosurgical procedure in children is the placement of a CSF shunt. The role of a CSF shunt is to divert CSF from the brain to another portion of the body. The proximal portion of the catheter may be in the cerebral ventricle, an intracranial cyst, or the lumbar subarachnoid space. Most commonly the CSF is shunted into the peritoneal cavity via a ventriculoperitoneal (VP) shunt. Occasionally the distal end drains into the vascular system via a ventriculoatrial (VA) shunt. Most CSF shunts are made of three components: proximal shunt tubing, a reservoir system, and distal shunt tubing.
Obstruction of the catheter lumen or disconnection of the component parts of a CSF shunt leads to malfunction. Shunt obstructions are most common within 6 months of shunt placement. Headache, visual disturbances, vomiting, and lethargy are the most common signs and symptoms of a mechanical shunt obstruction. In infants who have an open fontanel, there may be an increase in head circumference or a bulging fontanel. Parents may report that the child is “not acting right” or is less active than usual. Seizures may be seen in those patients with predisposing brain lesions; however, they are uncommonly the sole manifestation of a CSF shunt malfunction.
On physical examination, signs of shunt malfunction include papilledema, an enlarging head, bulging fontanel, and engorged head veins. Abnormalities on neurologic examination include increased deep tendon reflexes, increased lower extremity tone, and a positive Babinski sign. Cranial nerve palsies of either the sixth cranial nerve leading to lateral gaze deviation or the fourth cranial nerve leading to limitation of upward gaze, also known as “sunsetting” gaze.