It’s a warm summer day when you’re dispatched for a 5-month-old having seizurelike activity. You arrive to find three firefighter/EMTs monitoring a small infant in a sparse living room. The patient has poor tone and is on a nonrebreather. It’s warm in the house—you notice there’s no air conditioning.
The first FF/EMT reports the patient was seizing when they arrived, and they’ve applied oxygen and cleared the area around him. The child stopped seizing after about a minute, and his breathing was shallow, so they started bag-mask ventilation. The patient’s blood glucose is 74 mg/dL.
You get a brief history from the patient’s mother, and it initially seems unremarkable: The patient is a baby boy, previously healthy with no allergies, takes no medication, and is formula-fed. His mother reports he’s been increasingly fussy over the past few days. He’s had no cough, congestion, runny nose, or breathing problems.
As you look around the home, you notice there’s only a couch in the living room—no toys, no baby items, only a small box of diapers in the corner. The patient is in tattered, dirty clothes and appears to have not been bathed in a few days. A saggy diaper appears to have not been changed in many hours. The patient’s mother also says he’s been hungrier than normal and crying for a bottle more over the past few days. Upon further questioning she says she doesn’t have much extra money and has been mixing in only a quarter to half of the recommended formula. She thought it would make the formula last longer without making a difference to the child.
With this information you conclude the seizures are due to water intoxication causing hyponatremia. You start a normal saline bolus and transport the boy to a local pediatric hospital.
Seizures are abnormal, unregulated electrical discharges in the brain that interrupt normal brain function.1 This can manifest externally as violent involuntary contractions of the voluntary muscles.
The etiology of seizures is complex. EMS providers often encounter chronic seizure patients for whom initial treatment with benzodiazepines is indicated. While some pediatric patients have been diagnosed with established seizure disorders, febrile seizures must also be considered.2 Febrile seizures are the most common neurological disorder in children,3 affecting 2%–5%, and usually have an onset associated with viral symptoms between the ages of 6–60 months.4
Benzodiazepines as rescue therapy for continuous seizures in the prehospital setting include midazolam and diazepam. In the U.S. the only FDA-approved medication for repetitive seizures is rectal diazepam.2 Common EMS protocols for undifferentiated seizures often include intramuscular, intranasal, and intravenous midazolam.5 While benzodiazepines will often abort seizures, it’s important to understand the etiology of seizures and treat that appropriately.6
Electrolyte imbalances—normally hyponatremia, hypomagnesemia, and hypocalcemia—can also be a relevant cause of seizures in pediatrics.7 In these cases it’s important to rapidly identify the underlying cause and correct the electrolyte imbalance to control the seizures and prevent permanent brain damage.
Hyponatremia is an electrolyte imbalance that can rapidly degrade to a life-threatening condition where sodium levels are notably decreased. A decrease in sodium in the plasma causes water to transfer into individual cells, sometimes causing the cells to rapidly swell and possibly burst, causing the contents to spill out.
Hyponatremia can be classified as mild (130–134 mEq/L), moderate (125–129 mEq/L), or severe (less than 125 mEq/L).7 A vast array of signs and symptoms present, often correlating to severity. Symptoms of mild to moderate hyponatremia may include mild headache, mild lethargy, and dizziness. In more severe cases symptoms may include confusion, seizures, ataxia, coma, and respiratory depression.8 Complications of acute hyponatremia with a serum concentration of less than 120 mEq/L can include cerebral edema and herniation, after which obtunded posturing can be seen.7
Always consider hyponatremia in those presenting with acute seizures and a body temperature of 36.5ºC (97.7ºF) or less.9 These patients need a correction in sodium. Often improvement in neurological function is seen more rapidly in children than adults.10
Severe hyponatremia is commonly treated with 3% hypertonic saline infusions, which shift water from the brain to the intravascular system, causing a rapid reduction in brain volume and intracranial pressure. In the absence of 3% hypertonic saline, a 20-ml/kg normal saline bolus is an acceptable replacement in the prehospital setting.11 This is followed by fluid restrictions and sodium levels that are corrected over a period of 48 hours.7
While kids are often looked at as very resilient, they often lack regulatory tolerance due to the immaturity of their endocrine system. A purposeful increase in the water volume in powdered formulas is enough to produce a significant shift in the plasma sodium level in the infant patient.
Formula-induced hyponatremia is often difficult to clinically recognize, as the initial symptom of water intoxication in those under a year old may be behavior changes.12 Other symptoms could include muscle cramps, twitching, nausea/vomiting, poor coordination, altered mental status, coma, and seizures. Many of these symptoms are difficult to identify in the young pediatric patient.
Formula dilution can occur for many reasons. Most often it’s an attempt to extend the use of expensive powdered formula. This was once a rare diagnosis in the United States, but the incidence of hyponatremia in infants due to dilution of formula is increasing.13 Estimates project this problem getting worse over time.
Formula is expensive. The average baby consumes 24–26 ounces a day, at a projected cost of up to $3.12.14,15 This equates to nearly $100 a month, or more than $1,100 a year. Currently, the federal minimum wage is $7.25 an hour, working out to an annual full-time salary of $15,080.16 This calculation equates to spending almost 8% of your pretax wages on feeding one infant for a year!
Evaluation and diagnosis of the infant is often challenging and can encompass a wide range of differential diagnoses. To assist in making an accurate diagnosis, a quality history and physical is imperative—this could be an important step in understanding the etiology of the seizing infant. The importance of the history and physical in the seizing pediatric patient places first responders in a unique position: They can capture critical pieces of information inaccessible to most others in the healthcare continuum, which could be essential to rapidly and accurately diagnosing a patient.
As a prehospital provider it is always important to gather a complete history, including feeding schedule, type of formula, how it is being mixed, and any recent changes in feeding schedule or type; a blood glucose level; any personal or family history of seizures; and an evaluation of recent illness.
Whenever the prehospital provider experiences an infant seizing, they should always have a differential diagnosis list that includes:
2. Agarwal SK, Cloyd JC. Development of benzodiazepines for out-of-hospital management of seizure emergencies. Neurol Clin Pract, 2015 Feb; 5(1): 80–85.
3. Leung AKC, Lun Hon K, Leung TNH. Febrile seizures: an overview. Drugs Context, 2018; 7: 212536.
4. Steering Committee on Quality Improvement and Management, Subcommittee on Febrile Seizures. Febrile Seizures: Clinical Practice Guidelines for the Long-term Management of the Child With Simple Febrile Seizures. Pediatrics, 2008 Jun; 121(6): 1,281–6.
5. Welch RD, Nicholas K, Durkalski-Mauldin VL, et al.; Neurological Emergencies Treatment Trials (NETT) Network Investigators. Intramuscular midazolam versus intravenous lorazepam for the prehospital treatment of status epilepticus in the pediatric population. Epilepsia, 2015 Feb; 56(2): 254–262.
6. Youn K, Tokeshi J. Therapy with hypertonic saline in combination with anti-convulsants for hyponatremia-induced seizure: a case report and review of the literature. Hawaii Med J, 2002 Dec; 61(12): 280–1.
8. Braun MM, Barstow CH, Pyzocha NJ. Diagnosis and management of sodium disorders: hyponatremia and hypernatremia. Am Fam Physician, 2015 Mar 1; 91: 299–307.
9. Farrar HC, Chande VT, Fitzpatrick DF, Shema SJ. Hyponatremia as the cause of seizures in infants: a retrospective analysis of incidence, severity, and clinical predictors. Ann Emerg Med, 1995; 26:42–48.
10. Van Amelsvoort T, Bakshi R, Devaux CB, Schwabe S. Hyponatremia associated with carbamazepine and oxcarbazepine therapy: a review. Epilepsia, 1994; 35: 181–8.
11. Grissinger M. Hyponatremia and death in healthy children from plain dextrose and hypotonic saline solutions after surgery. P&T, 2013 Jul; 38 (7): 364–88.
12. St. Louis Children’s Hospital. Water Intoxication in Infants, www.stlouischildrens.org/health-resources/pulse/water-intoxication-infants.
13. Bruce RC, Kliegman RM. Hyponatremic Seizures Secondary to Oral Water Intoxication in Infancy: Association With Commercial Bottled Drinking Water. Pediatrics, 1997 Jan; 100(6).
14. Oliveira V, Prell M, Smallwood D, Frazao E. Infant Formula Prices and Availability: Final Report to Congress. Food Assistance & Nutrition Research Program, www.ers.usda.gov/webdocs/publications/43025/35759_efan02001.pdf?v=0.
15. HealthyChildren.org. Amount and Schedule of Formula Feedings, www.healthychildren.org/English/ages-stages/baby/formula-feeding/Pages/Amount-and-Schedule-of-Formula-Feedings.aspx.
16. U.S. Department of Labor. Consolidated Minimum Wage Table, www.dol.gov/whd/minwage/mw-consolidated.htm.
David Wright, MS, PA-C, NRP, is a physician assistant working in the Division of Pediatric Emergency Medicine at Washington University in St. Louis.