eMedicine Specialties > Emergency Medicine > Pediatric

Pediatrics, Dehydration

Alison Wiley Lozner, MD, Resident Physician, Harvard Affiliated Emergency Medicine Residency, Brigham and Women's Hospital; Clinical Fellow in Emergency Medicine, Harvard Medical School
James Kimo Takayesu, MD, Instructor in Surgery, Director of Undergraduate Medical Education, Consulting Staff, Massachusetts General Hospital; Associate Residency Director, Harvard Affiliated Emergency Medicine Residency Partners

Updated: Feb 5, 2009

Introduction

Background

Volume depletion is a common complication of illness observed in pediatric patients presenting to the emergency department (ED). At times, it is the presenting complaint. Early recognition and early intervention are important to prevent progression to shock and cardiovascular collapse.

Pathophysiology

Pediatric dehydration is frequently the result of gastroenteritis, characterized by vomiting and diarrhea. However, other causes of dehydration may include poor oral intake due to diseases such as stomatitis, insensible losses due to fever, or osmotic diuresis from uncontrolled diabetes mellitus.

The terms dehydration and volume depletion are commonly used interchangeably to denote intravascular fluid depletion. However, it is useful for clinicians to understand that volume depletion is distinct from dehydration.

Volume depletion denotes contraction of the total intravascular plasma pool, whereas dehydration denotes loss of plasma-free water disproportionate to loss of sodium, the main intravascular solute. The distinction is important because volume depletion can exist with or without dehydration, and dehydration can exist with or without volume depletion.

In children with dehydration, the most common underlying problem actually is volume depletion, not dehydration. Intravascular sodium levels are within the reference range, indicating that excess free water is not being lost from plasma. Rather, the entire plasma pool is contracted with solutes (mostly sodium) and solvents (mostly water) lost in proportionate quantities. This is volume depletion without dehydration. The most common cause is excessive extrinsic loss of fluids.

Pediatric patients, especially those younger than 4 years, tend to be more susceptible to volume depletion as a result of vomiting, diarrhea, or increases in insensible water losses. Significant fluid losses may occur rapidly. The turnover of fluids and solute in infants and young children can be as much as 3 times that of adults. This is because of the following:

Higher metabolic rates
Increased body surface area to mass index
Higher body water contents (Water comprises approximately 70% of body weight in infants, 65% in children, and 60% in adults.)

Sodium considerations

Volume depletion can be concurrent with hyponatremia. This is characterized by plasma volume contraction with free water excess. An example is a child with diarrhea who has been given tap water to replete diarrheal losses. Free water is replenished, but sodium and other solutes are not.

In hyponatremic volume depletion, the patient may appear more ill clinically than fluid losses indicate. The degree of volume depletion may be clinically overestimated. Serum sodium levels less than 120 mEq/L may result in seizures. If intravascular free water excess is not corrected during volume replenishment, the shift of free water to the intracellular fluid compartment may cause cerebral edema.

With true dehydration, plasma volume contracts with disproportionate further free water loss. An example is the child with diarrhea whose fluid losses have been replenished with hypertonic soup, boiled milk, baking soda, or improperly diluted infant formula. Volume has been restored, but free water has not.

In hypernatremic volume depletion, the patient may appear less ill clinically than fluid losses indicate. The degree of volume depletion may be underestimated. Usually, at least a 10% volume deficit exists with hypernatremic volume depletion.

As in hyponatremia, hypernatremic volume depletion may result in serious central nervous system (CNS) effects as a result of structural changes in central neurons. However, cerebral shrinkage occurs instead of cerebral edema. This may result in intracerebral hemorrhage, seizures, coma, and death. For this reason, volume restoration must be performed gradually over 24 hours or more. Gradual restoration prevents a rapid shift of fluid across the blood-brain barrier and into the intracellular fluid compartment.

Potassium considerations

Potassium shifts between intracellular and extracellular fluid compartments occur more slowly than free water shifts. Serum potassium level may not reflect intracellular potassium levels. Although a potassium deficit is present in all patients with volume depletion, it is not usually clinically significant. However, failure to correct for a potassium deficit during volume repletion may result in clinically significant hypokalemia. Potassium should not be added to replacement fluids until adequate urine output is obtained.

Acid and base problems

Clinicians may observe derangements of acid-base balance with volume depletion. Some degree of metabolic acidosis is common, especially in infants.

Mechanisms include bicarbonate loss in stool and ketone production. Hypovolemia causes decreased tissue perfusion and increased lactic acid production. Decreased renal perfusion causes decreased glomerular filtration rate, which, in turn, leads to decreased hydrogen (H⁺) ion excretion. These factors combine to produce a metabolic acidosis.

In most patients, acidosis is mild and easily corrected with volume restoration (as increased renal perfusion permits excretion of excess H⁺ ions in the urine). Administration of glucose-containing fluids further decreases ketone production.

Frequency

United States

Pediatric dehydration, particularly that due to gastroenteritis, is a common ED complaint. Approximately 200,000 hospitalizations and 300 deaths per year are attributed to gastroenteritis each year.

International

According to the Centers for Disease Control and Prevention (CDC), for children younger than 5 years, the annual incidence of diarrheal illness is approximately 1.5 billion, while deaths are estimated between 1.5 and 2.5 million. Though these numbers are staggering, they actually represent an improvement from the early 1980s, when the death rate was approximately 5 million per year.¹

Mortality/Morbidity

Morbidity varies with the degree of volume depletion and the underlying cause.
The severely volume-depleted infant or child is at risk for death from cardiovascular collapse.
Hyponatremia resulting from replacement of free water alone may cause seizures.
Improper management of volume repletion may cause iatrogenic morbidity or mortality.

Age

Infants and younger children are more susceptible to volume depletion than older children.

Clinical

History

The goal of the history and physical examination is to determine the severity of the child's condition. Classifying the degree of dehydration as mild, moderate, or severe accurately allows for appropriate therapy and disposition of the patient in a timely fashion.

Obtaining a complete history from the parent or caregiver is important because it provides clues to the type of dehydration present.

The emergency physician should be diligent in obtaining the following information:

Feeding pattern and fluids given
Number of wet diapers compared with normal
Fluid loss (eg, vomiting, oliguria or anuria, diarrhea)
Possible ingestions
Activity
Medications
Heat and sunlight exposures

Physical

The following table highlights the physical findings seen with different levels of pediatric dehydration.

Symptom	Mild (<3% body weight lost)	Moderate (3-9% body weight lost)	Severe (>9% body weight lost)
Mental status	Normal, alert	Restless or fatigued, irritable	Apathetic, lethargic, unconscious
Heart rate	Normal	Normal to increased	Tachycardia or bradycardia
Quality of pulse	Normal	Normal to decreased	Weak, thready, impalpable
Breathing	Normal	Normal to increased	Tachypnea and hyperpnea
Eyes	Normal	Slightly sunken	Deeply sunken
Fontanelles	Normal	Slightly sunken	Deeply sunken
Tears	Normal	Normal to decreased	Absent
Mucous membranes	Moist	Dry	Parched
Skin turgor	Instant recoil	Recoil <2 seconds	Recoil >2 seconds
Capillary refill	<2 seconds	Prolonged	Minimal
Extremities	Warm	Cool	Mottled, cyanotic

Adapted from King et al¹

Of these, the most accurate in identifying the level of dehydration are capillary refill, skin turgor, and breathing. The least accurate are mental status, heart rate, and fontanelle appearance.

Causes

In most cases, volume depletion in children is from fluid losses from vomiting or diarrhea.

Vomiting may be caused by any of the following systems or processes:

CNS (eg, infections, space-occupying lesions)
GI (eg, gastroenteritis, obstruction, hepatitis, liver failure, appendicitis, peritonitis, intussusception, volvulus, pyloric stenosis, toxicity [ingestion, overdose, drug effects])
Endocrine (eg, diabetic ketoacidosis [DKA], congenital adrenal hypoplasia, Addisonian crisis)
Renal (eg, infection, pyelonephritis, renal failure, renal tubular acidosis)
Psychiatric (eg, psychogenic vomiting) - This is not seen in infants and is rare in children compared with adults.

Diarrhea may be caused by any of the following systems or processes:

GI (eg, gastroenteritis, malabsorption, intussusception, irritable bowel, inflammatory bowel disease, short gut syndrome)
Endocrine (eg, thyrotoxicosis, congenital adrenal hypoplasia, Addisonian crisis, diabetic enteropathy)
Psychiatric (eg, anxiety)
Volume depletion not caused by vomiting or diarrhea may be divided into renal or extrarenal causes.
- Renal causes include use of diuretics, renal tubular acidosis, and renal failure (eg, trauma, obstruction, salt-wasting nephritis). The effects of diabetes insipidus, hypothyroidism, and adrenal insufficiency also fall into this category.
- Extrarenal causes include third-space extravasation of intravascular fluid (eg, pancreatitis, peritonitis, sepsis, heart failure); insensible losses from fever, sweating, burns, or pulmonary processes; poor oral intake; and hemorrhage.

Differential Diagnoses

Diabetic Ketoacidosis	Pediatrics, Gastroenteritis
Fever in the Neonate and Young Child	Pediatrics, Gastrointestinal Bleeding
Heat Exhaustion and Heatstroke	Pediatrics, Intussusception
Hypernatremia	Pediatrics, Pyloric Stenosis
Hyperosmolar Hyperglycemic Nonketotic Coma	Shock, Hemorrhagic
Hypokalemia	Shock, Hypovolemic
Hyponatremia	Shock, Septic
Metabolic Acidosis	Toxicity, Salicylate
Pediatrics, Dehydration
Pediatrics, Diabetic Ketoacidosis
Pediatrics, Fever

Workup

Laboratory Studies

Laboratory studies are of limited utility in cases of mild dehydration. However, they should be considered under certain conditions.

Consider a fingerstick to check serum glucose level if either hyperglycemia or hypoglycemia is suspected.
Consider checking serum electrolytes in the moderately dehydrated child if the history or physical examination findings is inconsistent with straightforward gastroenteritis.
Check serum electrolyte levels in all children with severe dehydration and in those receiving intravenous fluids.
Pursue appropriate testing when a diagnosis other than straightforward gastroenteritis is suspected.

For children who are in profound hypovolemic shock, the following studies are recommended:

Basic metabolic panel: Serum electrolyte levels are important to determine sodium concentration, which can guide replenishment therapy. Bicarbonate and potassium levels also are important to assess the degree of metabolic acidosis and to screen for coexisting hypokalemia. Blood urea nitrogen and creatinine levels measure renal function and intravascular volume. Glucose level may reveal hyperglycemia or hypoglycemia.
Venous blood gas: Venous blood gas measurements are indicated in patients with severe volume depletion. Serum pH provides a more direct measure of acidosis than the calculated bicarbonate level.
Lactic acid: Serum lactate level is indicative of tissue perfusion and oxygenation. It may be helpful in cases of severe dehydration or sepsis.
Complete blood cell count: CBC may be helpful in cases in which dehydration is due to sepsis or hemorrhage.
Urinalysis: Urine specific gravity indicates the degree of volume depletion and may reveal an underlying infectious etiology.

Procedures

Prior to vascular access attempts, consider oral rehydration in mild and moderate dehydration.

Intravenous access: Typical sites include superficial veins in the dorsum of the hand, antecubital fossa (median cephalic or basilic veins), dorsum of the foot, and scalp veins.
Intraosseous access
- Use intraosseous access if attempts to start percutaneous intravenous lines are unsuccessful.
- Typical sites are the proximal tibia and the distal femur.
Central venous access
- Typical sites are femoral, external jugular (may be difficult because of short neck in infants and young children), subclavian, and antecubital veins.
- Umbilical vein catheterization may be difficult and usually is not recommended for neonates who have been discharged from the hospital and are returning to the ED.
Venous cutdown
- Use venous cutdown for emergent access and resuscitation only. Safe performance depends on the skill of the provider.
- The typical site is the distal saphenous vein, which is anterior and superior to the medial ankle malleolus.

Treatment

Prehospital Care

Address emergent airway, breathing, and circulatory problems first.
Obtain intravenous access, and give an isotonic fluid bolus (Ringer lactate or isotonic sodium chloride solution) to children with severe volume depletion. This should not delay transport to the appropriate facility.

Emergency Department Care

Mild dehydration

Patients with minimal-to-mild dehydration should be encouraged to continue an age-appropriate diet and adequate intake of oral fluids. Oral rehydration solution (ORS) should be used. Children should be given sips of ORS (5 mL or one teaspoon) every 5 minutes. As an estimate for the amount of fluid to replace, the goal should be to drink 10 mL/kg body weight for each watery stool and 2 mL/kg body weight for each episode of vomiting.¹

If commercially prepared ORS is not available, the following recipe may be followed:

In 1 liter of water, add 2 level tablespoons of sugar or honey, one-fourth teaspoon of table salt (NaCl), and one-fourth teaspoon of baking soda (bicarbonate of soda).
If baking soda is not available, use another quarter teaspoon of salt instead.
If available, add one half cup of orange juice, coconut water, or a mashed ripe banana to the drink.
The water is safer if boiled, but do not lose time doing this if the child is very ill.
Before giving the drink, taste it to be sure it is no saltier than tears.

Moderate dehydration

The literature supports use of oral rehydration for the moderately dehydrated child. Similar outcomes have been achieved in randomized studies comparing ORS with intravenous fluid therapy (IVF) with fewer complications and higher parent satisfaction in the ORS groups. Moreover, ORS can typically be initiated sooner than IVF. However, children must be cooperative and have caregivers available to instruct and administer the oral fluids.²

With ORS, patients should receive approximately 50-100 mL/kg body weight over 2-4 hours, again starting with 5 mL every 5 minutes.¹ If the child can tolerate this amount and asks for more fluids, the amount given can gradually be increased. Once the fluid deficit has been corrected, parents should be instructed on how to replace volume losses at home if the child continues to have vomiting or diarrhea.

Children who fail ORS should be given a 20-mL/kg bolus of isotonic fluid intravenously. This may be followed by 1.5-2 times maintenance therapy as described below. Over the next few hours, the patient may be transitioned to oral rehydration as tolerated, at which point, the intravenous therapy may be discontinued.

Severe dehydration

Patients with severe dehydration should receive intravenous isotonic fluids in 20- to 60-mL/kg fluid boluses.¹ In children with difficult peripheral access, perform intraosseous or central access promptly. Fluid boluses should be repeated until vital signs, perfusion, and capillary refill have normalized. If a patient reaches 60-80 mL/kg in isotonic crystalloid boluses and is not significantly improved, consider other causes of shock (eg, sepsis, hemorrhage, cardiac disease) and consider vasopressors and advanced monitoring such as with a bladder catheter, central venous pressure, and measuring mixed venous oxygen saturation.

Although physicians typically give normal saline for these initial boluses, it is important to remember to check a bedside glucose level for patients who appear lethargic or altered. Treat hypoglycemia promptly. The appropriate dose is 0.25 g/kg (2.5 mL/kg of 10% dextrose or 1 mL/kg of 25% dextrose) IV.

Once vital sign abnormalities are corrected, initiate maintenance fluid therapy plus additional fluid to make up for any continued losses. For the early phase of rehydration, 1.5-2 times maintenance therapy should be adequate. Daily requirements for maintenance fluids can be approximated as follows:

If the patient weighs less than 10 kg, give 100 mL/kg/d.
If the patient weighs less than 20 kg, give 1000 mL/d plus 50 mL/kg/d for each kilogram between 10-20 kg.
If the patient weighs more than 20 kg, give 1500 mL/d, plus 20 mL/kg/d for each kilogram over 20 kg.
Divide the total by 24 to obtain the hourly rate.

Daily fluid requirements may be met using dextrose 5% in half-normal saline solution. For those with significant hyponatremia or hypernatremia, it is preferable to use dextrose 5% in normal saline. Dextrose is important to include because these patients generally have a notable ketosis.

The emergency physician also should consider daily sodium and potassium requirements as follows:

Sodium 2-3 mEq/kg/d
Potassium 2-3 mEq/kg/d

Isonatremic and hyponatremic volume depletion states may be treated with normal saline or other isotonic solutions.

Hypernatremic volume depletion should be corrected more slowly because of the possibility of CNS complications resulting from rapid correction of the osmolar gradients. Full correction of severe sodium abnormalities usually should be staged over 24 hours or longer.

Although a potassium deficit is present in all cases of volume depletion, it is not usually clinically significant; few patients with moderate dehydration require supplemental potassium. However, failure to correct for hypokalemia during volume repletion may result in clinically significant hypokalemia. Add potassium to fluids when the patient has documented hypokalemia. For all other patients, avoid adding potassium to fluids until the patient has received several hours of resuscitation and the patient has demonstrated adequate urine output.

Consultations

Infants and children who present to the ED with mild-to-moderate dehydration may respond to fluid boluses and be discharged home with close follow-up with their primary care provider.

Patients who are severely volume depleted or who are unable to tolerate oral fluids must be admitted, with a pediatric consultation if appropriate.

If the child is in shock, unable to drink fluids, or does not respond to intravenous bolused therapy, significant abnormalities requiring correction may exist. In such patients, obtain pediatric consultation for admission and further therapy.
If renal tubular acidosis (RTA) or other primary renal or endocrine disorder is suspected, specialty consultation may be indicated.

Medication

Acute gastroenteritis is typically a self-limited condition that does not require antibiotics. Chronic infectious cases of diarrhea may require antimicrobial agents after appropriate stool studies have indicated the etiology. Antidiarrheal agents are not recommended.

When dehydration is caused by other disease processes, such as diabetic ketoacidosis or sepsis, appropriate pharmacologic therapy should be initiated as soon as possible.

The emergency medicine literature now supports the use of a single dose of oral ondansetron in combination with oral rehydration for patients with dehydration, nausea, and vomiting.³ However, the use an antiemetic should not shift the focus away from adequate fluid resuscitation.

Follow-up

Further Inpatient Care

Inpatient therapy generally is not indicated for mild volume depletion. However, it is prudent to arrange outpatient follow-up evaluation within 48 hours, with instructions to return sooner if needed.
Children with moderate volume depletion may require inpatient treatment if they are unable to tolerate oral fluids despite rehydration or if they require treatment of the underlying etiology of the fluid deficit.
Children with severe volume depletion, especially patients with hypernatremia or hyponatremia, require inpatient therapy. Children with severe hyperosmolar states, severe electrolyte derangements, or associated renal failure may require admission to a critical care unit.

Prognosis

Generally, prognosis is excellent if appropriately treated.

Patient Education

For excellent patient education resources, visit eMedicine's Children's Health Center. Also, see eMedicine's patient education article Dehydration in Children.

Miscellaneous

Medicolegal Pitfalls

Iatrogenic electrolyte imbalance
Overly aggressive replacement of volume deficits leading to serious CNS sequelae
Failure to diagnose sepsis or another more serious underlying condition
Failure to admit to recognize and treat shock

References

King CK, Glass R, Bresee JS, et al. Managing acute gastroenteritis among children: oral rehydration, maintenance, and nutritional therapy. MMWR Recomm Rep. Nov 21 2003;52(RR-16):1-16. [Medline].
[Best Evidence] Spandorfer PR, Alessandrini EA, Joffe MD, Localio R, Shaw KN. Oral versus intravenous rehydration of moderately dehydrated children: a randomized, controlled trial. Pediatrics. Feb 2005;115(2):295-301. [Medline].
[Best Evidence] Freedman SB, Adler M, Seshadri R, Powell EC. Oral ondansetron for gastroenteritis in a pediatric emergency department. N Engl J Med. Apr 20 2006;354(16):1698-705. [Medline].
2005 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. Dec 13 2005;112(24 Suppl):IV1-203. [Medline].
[Best Evidence] Alhashimi D, Alhashimi H, Fedorowicz Z. Antiemetics for reducing vomiting related to acute gastroenteritis in children and adolescents. Cochrane Database Syst Rev. Oct 18 2006;CD005506. [Medline].
American Academy of Pediatrics. Practice parameter: the management of acute gastroenteritis in young children. American Academy of Pediatrics, Provisional Committee on Quality Improvement, Subcommittee on Acute Gastroenteritis. Pediatrics. Mar 1996;97(3):424-35. [Medline].
Barkin RM, Ward DG. Infectious diarrheal disease and dehydration. In: Marx JA. Rosen's Emergency Medicine: Concepts and Clinical Practice. Vol 3. 6^th ed. Philadelphia, Pa: Mosby/Elsevier; 2006:2623-34.
Bezerra JA, Stathos TH, Duncan B, Gaines JA, Udall JN Jr. Treatment of infants with acute diarrhea: what's recommended and what's practiced. Pediatrics. Jul 1992;90(1 Pt 1):1-4. [Medline].
Carcillo JA, Davis AL, Zaritsky A. Role of early fluid resuscitation in pediatric septic shock. JAMA. 1991;266(9):1242-5. [Medline].
De Bruin WJ, Greenwald BM, Notterman DA. Fluid resuscitation in pediatrics. Crit Care Clin. Apr 1992;8(2):423-38. [Medline].
Holliday M. The evolution of therapy for dehydration: should deficit therapy still be taught?. Pediatrics. Aug 1996;98(2 Pt 1):171-7. [Medline].
Idris AH, Melker RJ. High-flow sheaths for pediatric fluid resuscitation: a comparison of flow rates with standard pediatric catheters. Pediatr Emerg Care. Jun 1992;8(3):119-22. [Medline].
Kallen RJ, Lonergan JM. Fluid resuscitation of acute hypovolemic hypoperfusion states in pediatrics. Pediatr Clin North Am. Apr 1990;37(2):287-94. [Medline].
Kersten H. Oral ondansetron decreases the need for intravenous fluids in children with gastroenteritis. J Pediatr. Nov 2006;149(5):726. [Medline].
Lozon MM. Pediatric vascular access and blood sampling techniques. In: Roberts JR, Hedges JR. Clinical Procedures in Emergency Medicine. 4^th ed. Philadelphia: WB Saunders; 2004:357-8.
Mange K, Matsuura D, Cizman B, et al. Language guiding therapy: the case of dehydration versus volume depletion. Ann Intern Med. Nov 1 1997;127(9):848-53. [Medline].
Steiner MJ, DeWalt DA, Byerley JS. Is this child dehydrated?. JAMA. Jun 9 2004;291(22):2746-54. [Medline].
Wathen JE, MacKenzie T, Bothner JP. Usefulness of the serum electrolyte panel in the management of pediatric dehydration treated with intravenously administered fluids. Pediatrics. Nov 2004;114(5):1227-34. [Medline].

Keywords

dehydration, dehydration in kids, dehydration in baby, dehydration symptoms, dehydration treatment, water loss, fluid loss, diarrhea, vomiting, volume depletion, hypovolemia, fluid deficit

Contributor Information and Disclosures

Author

Alison Wiley Lozner, MD, Resident Physician, Harvard Affiliated Emergency Medicine Residency, Brigham and Women's Hospital; Clinical Fellow in Emergency Medicine, Harvard Medical School
Alison Wiley Lozner, MD is a member of the following medical societies: American Academy of Emergency Medicine and American College of Emergency Physicians
Disclosure: Nothing to disclose.

Coauthor(s)

James Kimo Takayesu, MD, Instructor in Surgery, Director of Undergraduate Medical Education, Consulting Staff, Massachusetts General Hospital; Associate Residency Director, Harvard Affiliated Emergency Medicine Residency Partners
James Kimo Takayesu, MD is a member of the following medical societies: Alpha Omega Alpha, American College of Emergency Physicians, Sigma Xi, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Medical Editor

James Li, MD, Former Assistant Professor, Division of Emergency Medicine, Harvard Medical School; Board of Directors, Remote Medicine
Disclosure: Nothing to disclose.

Pharmacy Editor

Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine
Disclosure: Pfizer Inc Stock Investment from financial planner; Avanir Pharma Stock Investment from financial planner ; WebMD Salary and stock Employment and investment from financial planner

Managing Editor

Wayne Wolfram, MD, MPH, Clinical Associate Professor, Departments of Pediatrics, Children's Hospital and University of Cincinnati
Wayne Wolfram, MD, MPH is a member of the following medical societies: American Academy of Emergency Medicine, American Academy of Pediatrics, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

CME Editor

John D Halamka, MD, MS, Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center
John D Halamka, MD, MS is a member of the following medical societies: American College of Emergency Physicians, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Chief Editor

Richard G Bachur, MD, Assistant Professor of Pediatrics, Harvard Medical School; Associate Chief and Fellowship Director, Attending Physician, Division of Emergency Medicine, Children's Hospital of Boston
Richard G Bachur, MD is a member of the following medical societies: American Academy of Pediatrics, Society for Academic Emergency Medicine, and Society for Pediatric Research
Disclosure: Nothing to disclose.

Acknowledgments

The authors and editors of eMedicine gratefully acknowledge the contributions of previous author, Ann G Egland, MD, and Terrence K Egland, MD, to the development and writing of this article.

Further Reading