Seizing the Moment: Can Hydrocephalus Cause a Seizure?

It is a lazy summer afternoon when you and your partner get a call for a seven year old male patient in an active seizure. You immediately stop your preparations for dinner and race to the truck, recalling on the way the pediatric dose of valium and where the last place was that you saw the Broselow Tape. As you and your partner arrive at the residence you are greeted by a frantic father, who signals to you from the front porch. You grab the cardiac monitor while your partner grabs the pediatric bag and take off racing into the house.

When you walk through the door you see a mother kneeling over a little boy, who is lying supine on the floor of the living room. She is crying, and rocking back and forth. As you approach, you see the child is breathing and has a patent airway, but his eyes are closed and he is unaware of your presence. Between sobs his mother tells you that he was in a seizure for approximately five minutes and was given a dose of Diastat (rectal valium), which caused the seizure to break within one to two minutes of administration. She also reports the patient has hydrocephalus and a VP shunt.

As you begin to assist your partner in preparing the cardiac monitor, he leans in and whispers, “What’s hydrocephalus? And what did she mean about a shunt?” You remember hearing those terms long ago in medic class but cannot recall what they mean. You make a mental note to research it later; after all, it is just part of his past medical history and should not affect your care now.

Pathophysiology

Unfortunately, in the above scenario, the patient’s past medical history that was provided by the mother had everything to do with the cause and future treatment of the seizure. Hydrocephalus can occur in pediatric and adult patients for a variety of reasons. This article will focus on hydrocephalus in the pediatric patient, its causes, treatment and the impacts it will have on the emergency responder.

Hydrocephalus means “water on the brain.” The brain is composed of four ventricles, which help to connect the different areas of the brain. They are also a conducting system for cerebral spinal fluid (CSF). The choroid plexus in the lateral, third and forth ventricles produces the majority of the CSF that circulates in the brain. The circulating CSF must also be drained from the ventricles. This occurs in the arachnoid villi, which drains into the sagittal sinus. When an alteration in the production or removal of CSF occurs, physiological signs and symptoms will be produced.

In the case of hydrocephalus, the problem can be an increase in the production of CSF within the ventricles, an obstruction within the ventricles themselves causing the fluid to be trapped, or a problem with the drainage and reabsorption of the CSF. No matter what the cause, the end result is the same—the ventricle(s) will enlarge and dilate to accommodate the extra fluid. Because the skull is a hard, rigid box it cannot expand. So the enlarging ventricles will compress nearby brain tissue—along with the blood vessels surrounding that tissue—leading to cognitive impairments and cerebral ischemia.

There are two types of hydrocephalus: communicating and non-communicating. Communicating hydrocephalus occurs when the ventricles are patent and CSF can flow between them, but there is a problem with the drainage and removal of the fluid. In non-communicating hydrocephalus, there is a physical blockage within one of the ventricles causing the fluid to remain trapped and unable to flow.¹ Hydrocephalus can also be acute or chronic.

Incidence

Approximately three out of 1,000 live births result in hydrocephalus.² This condition can occur immediately at birth, or may be delayed until infancy or childhood. There are many causes of hydrocephalus. The most common causes of congenital hydrocephalus are due to a stenosis of the aqueduct that drains the CSF, myelomeningocele (a neural tube defect that occurs during fetal development, in which part of the spinal cord protrudes through the vertebrae), or malformations such as a Chiari or Dandy-Walker Malformation. It can also be present in infants born with Down syndrome. Hydrocephalus can also occur after birth because of tumor development, trauma from a head injury that leads to cerebral hemorrhage or from infections such as meningitis.

Pseudotumor cerebri, although most commonly seen in obese women of childbearing age, can occur in the pediatric population. Also termed idiopathic intracranial hypertension, this condition causes an increase in intracranial pressure without a known cause, such a tumor. Typically, this condition occurs later in childhood around the ages of 10 or 11. Although the causative agent may be unknown, there is a rise in ICP that must be corrected via medication therapy or shunt placement.

Physical Presentation

Hydrocephalus can occur without any outright physical signs or changes in appearance. Sometimes, however, the ventricles enlarge so much that the skull will expand and separate to allow for the brain to swell. This is seen in infants within the first two years of life when the anterior fontanel has not closed to allow the brain to expand. These infants will have enlarged skulls that are obvious in appearance. Head circumference is measured routinely in infancy and will be accelerated at an abnormal rate.

Also, the child may manifest signs of increased intracranial pressure, which includes, in its earliest stages, confusion, lethargy and vomiting that progresses rapidly to alterations in respirations, bradycardia, a widened pulse pressure and dilated, fixed pupils (Cushing reflex). A diagnosis of hydrocephalus is usually confirmed with either a CT scan or MRI. Also, depending on the child’s age, developmental milestones are assessed, and oftentimes found to be delayed. Paramedics should perform a complete neurological examination that is appropriate for the age of the patient. Also, these patients should have a complete and trending set of vital signs performed every 5–10 minutes to evaluate for the presence of the Cushing reflex, which can indicate elevated ICP.

Treatment

Treatments vary on the cause of the hydrocephalus. If the cause is due to a blockage of the aqueduct that drains the CSF from the ventricles, then a shunt can be placed to allow the fluid to flow properly out of the ventricle, thus reducing its size. The shunt usually contains a one-way valve to prevent fluid from returning to the ventricle. Within this valve, there may be a reservoir that holds a sample of the fluid to allow physicians to “tap the shunt” either to remove excess fluid or to test the fluid for possible infection.

The first part of the shunt is placed into the ventricle of the brain. The distal end is then placed into a body cavity to allow the CSF to drain. Most commonly, this is the peritoneal cavity, but it can drain into the right atrium via the subclavian or internal jugular vein.³ If the catheter drains into the peritoneal cavity, then it is known as a ventriculoperitoneal shunt (VP shunt); if it drains into the atria, then it is a ventriculoatrial shunt (VA shunt). The shunt can also drain into the pleura of the chest and is called a ventriculopleural shunt (also called a VP shunt). Knowing the type of shunt will allow the emergency provider to troubleshoot possible problems with the shunt.

Prior to surgical intervention, the patient may be treated with a variety of medications. Furosemide (Lasix) is a loop diuretic that promotes the excretion of sodium, water and potassium, which causes a decrease in intravascular volume, thus decreasing blood pressure. This will help control intracerebral hypertension. Steroids may also be used to decrease intracerebral edema and inflammation. Steroid therapy is usually initiated for only a short duration because of an array of side effects, which includes delayed bone growth (height), weak and brittle bones, hyperglycemia, susceptibility to infections, and cataracts. Carbonic anhydrase inhibitors, such as acetazolamide (Diamox), can be used to decrease the production of CSF and help prevent seizures. These patients are also likely to be on anticonvulsant therapy for prophylactic seizure prevention. Anticonvulsant drugs may include, but are not limited to, phenobarbital, Depakote, Dilantin, Tegretol, Lamictal and Topamax.

Complications

A shunt dysfunction can occur at any point after placement. Any time a shunt malfunctions, despite the cause, it will place the child at a greater risk of brain injury from a rebound increase in CSF. Depending on the length of time of the reoccurring hydrocephalus, the child may experience developmental and cognitive delays, which can greatly impact the child’s quality of life. Shunts can become occluded either from growing tissue or scar tissue, they can break at any location, become infected, or drain too much or too little fluid from the brain. As the child grows, the shunt will need to be revised to accommodate the growing body. All of these problems can lead to a medical emergency and the activation of the EMS system. See Table 1 for a list of shunt complications.²

A shunt infection most commonly occurs within the first six months of placement.² Some infections can be treated with intravenous antibiotics but others require the shunt to be fully removed, the infection cured and the shunt to be reinserted. EMS providers should assess any pediatric patient with a shunt for possible signs of infection. Inquire about when the shunt was placed. Also, assess the patient’s temperature, skin turgor and appearance, oral intake, and urinary output. Younger children often manifest signs of an infection as dehydration and will have hot, red, dry skin, along with dry oral mucous membranes. The child may not have an adequate intake of oral liquids and may also have a decrease in the amount of wet diapers being produced. The child can also be lethargic with a decrease in the level of activity and play.

Meningitis can also be a cause of infection for the patient. Paramedics should be aware of this and assess for a sudden, highly elevated temperature, decreasing mental status and, in older children, the presence of a headache or stiff neck. Some types of meningitis can be spread by respiratory droplets, so EMS providers should immediately initiate droplet isolation precautions as advised by the CDC or local protocols if meningitis is suspected.

The shunt may also become occluded either within the ventricle of the brain or at the distal end point. Causes of occlusion can vary but scar tissue is a frequent cause along with clot formation if the distal end is placed into the vascular system. The distal end of the shunt may also press up against the wall of the organ into which it drains causing an occlusion.

As a child grows or engages in activity, the shunt may weaken and break, causing CSF to either drain into an abnormal body cavity at the location of the break or not allow the fluid to drain at all, causing it to build up in the ventricle. EMS providers may not know the exact cause of the occlusion but may be able to troubleshoot based on this knowledge. If you suspect a break due to trauma or recent abnormal activity, assess the entire length of the shunt, from the head to the neck, to the chest or abdomen to look for any pockets of fluid retention, but do not push directly on the shunt as you examine the patient.

Lastly, the shunt may drain too much CSF from the brain or it may not drain enough. Overdrainage can result in small, slit-like ventricles that damage the brain and can possibly lead to hematoma formation.² The paramedic should assess the older child for the presence of any headaches, vision changes, dizziness or gait disturbances. The most common presenting symptom is an intermittent headache.² This may be the only presenting symptom and may be easily overlooked by the parents or caregiver. A quick assessment and a few select detailed questions may help the child receive proper care for a potential shunt complication.

Epilepsy

Returning to the case scenario at the beginning of this article, the EMS team was presented with a 7-year-old male patient with a history of hydrocephalus and a VP shunt who seized for approximately five minutes prior to EMS arrival. The patient’s mother stated she gave the child Diastat, which terminated the seizure. The paramedic on the crew did not feel hydrocephalus was a possible cause or related to the patient’s seizure. Was he right? Does hydrocephalus have anything to do with epilepsy? To answer this question, a literature review of evidence-based practice was conducted. The most recent articles on this topic focus on a review of the literature, rather than actually performing the research studies; this is known as a meta-analysis.

The article by Sato, et al.³ was written in 2001 and served to review the original pilot studies conducted on the topic. After their extensive review of the eight most popular studies, they concluded that in seven out of eight studies there was a positive correlation between epilepsy and hydrocephalus in children.

They also listed possible factors that could contribute to the prevalence of epilepsy in these children. They are: the cause of hydrocephalus; the age at diagnosis of hydrocephalus or the placement of a shunt with those younger patients at a greater risk for epilepsy; the presence and number of burr holes in the skull; any occurrence of increased intracranial pressure; the time between shunt insertion and the initial onset of a seizure; the number of shunt revisions; the use of antiepileptic medications; shunt complications; and the presence of brain anomalies.

Sato, et al.³ also noted mental retardation in children led to an increase in the occurrence of epilepsy—almost four times that of a child without mental retardation. In contrast, they concluded epilepsy was associated with a lower IQ score, so it cannot be determined if the seizures cause the lower IQ scores, thus mental retardation, or if the mental retardation is an indicator for the epilepsy.

Two other studies^4,5 looked at the occurrence of epilepsy in children with hydrocephalus by conducting a hospital chart review. Both found a positive correlation between the two; however, one study⁴ found no association between the occurrence of the seizure and the number of shunt revisions, or the location of the shunt within the brain. The authors found the greatest predictor of seizures occurred from brain anomalies, which includes hydrocephalus.

Conclusion

Recalling the scenario presented at the beginning of this article, you and your partner carefully perform a detailed physical assessment on the 7-year-old patient. His vitals signs are within normal limits. You apply oxygen and the cardiac monitor, while your partner initiates IV access and obtains a blood sample for glucose monitoring. The patient is transported to the nearest hospital and while en route begins to regain consciousness and is able to follow commands. There is no further seizure activity noted during transport, and upon arrival at the hospital the patient is fully awake and asking for his mother.

During your next shift you follow up with the ER doctor who cared for your patient. You learn his seizure was caused by a rapid increase in intracranial pressure due to a blockage of the shunt. Under the care of a neurologist, the shunt was tapped and cerebral spinal fluid was drained, thus allowing the ICP to return to normal. The patient was kept overnight for observation and was discharged home the next day without any further complications.

When responding to future calls involving children with hydrocephalus or VP shunts, it is important for the EMS provider to recognize the pathophysiology of the condition and to troubleshoot possible problems. Having a basic knowledge of this condition will allow you to provide better care to this special population and may help to alleviate some of the fears parents or caregivers may have regarding a new onset of epilepsy. By understanding possible shunt complications, you can direct your care to assess the specific problem, whether it be initiating treatment for an infection or recognizing the need for transport for a possible break in the shunt due to rough physical activity or trauma. As EMS providers, we encounter a variety of special populations. Having a little insight into them will allay some of our anxiety that comes from the unknown. Next time you encounter a situation in which our EMS crew did, step back, take a breath and do what you do best—care for those in their time of need.

Table 1²

1. Infection
2. Mechanical failure: breaks, kinks, migration
3. Overdrainage—slit ventricles
4. Overdrainage—subdural hygroma or chronic subdural hematoma
5. Blockage: proximal or distal, total or partial intermittent
6. Complications specific for ventriculocardiac shunts:
1. Thrombosis around the distal tube
2. Cor pulmonale
3. Shunt nephritis
4. Septicemia and pyemic abscesses
7. Complications specific for ventriculopleural shunts:
1. Hydrothorax: characterized by respiratory distress
2. Pyothorax
8. Abdominal complications of ventriculoperitoneal shunts:
1. Bowel perforation: rare with current catheter materials
2. Pseudocyst: sterile or infected and presenting as obstruction or abdominal swelling
3. Ascites: malabsorption of CSF; sterile or infected
4. Hernia: at shunt insertion incisions

References

1. McCance KL, Huether SE, eds. Pathophysiology: the biologic basis for disease in adults and children, 6^th ed. Maryland Heights, MO: Mosby Elsevier, 2010.
2. McInery TK, Adam HM, Campbell DE, Kamat DM, Kelleher KJ, eds. American academy of pediatrics textbook of pediatric care. Elk Grove Village, IL: American Academy of Pediatrics, 2009.
3. Sato O, Yamguchi T, Kittaka M, Toyama H. Hydrocephalus and epilepsy. Child's Nervous System: Chns: Official Journal Of The International Society For Pediatric Neurosurgery, 2001; 17(1–2): 76–86.
4. Keene D, Ventureyra E. Hydrocephalus and epileptic seizures. Child's Nervous System: Chns: Official Journal Of The International Society For Pediatric Neurosurgery, 1999; 15(4), 158–162.
5. Piatt J, Carlson C. Hydrocephalus and epilepsy: an actuarial analysis. Neurosurgery, 1996; 39(4), 722–727.

Valerie Matyus is a registered nurse and a prehospital RN in the state of Pennsylvania. She is currently attending the University of Pittsburgh to obtain a master’s degree as a family nurse practitioner.