Sudden infant death syndrome (SIDS) is the most common cause of mortality for babies between 1 and 12 months of life. Trying to identify which infants presenting with apparent life threatening events (ALTE) may go on to experience this horrible outcome is a challenge for the emergency physician. This article will highlight some steps to make the choice of investigative options and the disposition decision-making process a bit easier.

Definition

While arguments have been raised recently as to the relevance of ALTE in predicting SIDS, the importance of this controversy remains low for the emergency physician. The fact remains that, until proven otherwise, infants presenting to the emergency department with an ALTE might be experiencing the only event that may enable the health care system to identify and prevent impending SIDS. The term ALTE refers to a condition in which an acute, unexpected event that frightens the caregiver occurs, usually in an infant. The event includes changes in the breathing pattern or color (e.g., pallor or cyanosis), with or without a change in muscle tone. With this definition being so broad, subjective, and all encompassing, emergency physicians face challenges even in identifying these patients.

History

During their first year of life, an estimated 1% of babies will experience an ALTE. The vast majority of these patients present to the emergency department with anxious and frightened caregivers. The emergency physician’s task is to identify patients with the highest risk of recurrence or mortality. This is best defined with a thorough history of the event, previous medical history, risk assessment for SIDS, and family history. Investing the time required for a thorough investigation of the history is clearly worthwhile. The description of the event will influence decision making far more than any other part of the physician–patient interaction (i.e., lab tests, imaging, etc.).¹

It takes time to establish a good sense of the event. The questions in the history are aimed at determining if a significant apneic episode occurred. Eliciting a detailed description of the event should include these questions:²

1. Where did the event take place?
2. How long did it last?
3. If present, did a home monitor go off?
4. Was the infant awake or asleep previously?
5. Was the infant breathing?
6. Was there a color change, and if so, what?
7. Was there a change in tone?
8. What resuscitation efforts were made?
9. When was the last feeding?
10. Did the infant vomit?

When investigating the infant’s history, these questions should be included:

1. Was the infant’s birth premature, and if so, what is the infant’s corrected age?
2. Are there any predisposing medical conditions?
3. Does he suffer from gastroesoph ageal reflux disease (GERD), and if so, how was it diagnosed?
4. Were there previous similar events?
5. Are there any current illnesses?

The history should also include a detailed assessment of risk factors for SIDS:

1. What was the room temperature?
2. What position was the baby in during the event?
3. How firm is the mattress?
4. Is there any bedsharing with others?
5. Were there soft blankets, pillows, or stuffed toy animals in bed?
6. Did the mother smoke during pregnancy or after?
7. Does the infant use a pacifier?
8. What is the infant’s access to toxins or medications?

Lastly, one should address family history that could be related to SIDS:

1. Did any of the infant’s siblings die an unexplained death in the first year of life?
2. Were there any other deaths in the family at a young age?
3. Are there any metabolic, neurologic, or cardiac conditions that family members suffer from?
4. Is there a risk for nonaccidental injury or Munchausen’s syndrome by proxy?

After completing the history, clinicians in most cases already may have a good idea of the severity of the event. When the history is suggestive of an infant who was physiologically compromised (i.e., significant apnea has occurred), admission for monitoring is warranted.

Physical Examination

A child who presents to the emergency department with a significant physical finding would not pose a great disposition dilemma. However, in most patients the physical exam will be unremarkable.1 Clues for an underlying condition masquerading as apnea should be considered on examination. These include:

1. Dysmorphic features.
2. Maxillofacial anomalies.
3. Signs of viral or bacterial infection.
4. Respiratory distress suggesting lung or metabolic conditions.
5. Cardiovascular assessment to reveal heart failure, shock, or cardiac anomalies.
6. Neurological impairment suggestive of neurological or electrolyte imbalance.

Investigations

Much debate surrounds the extent of investigations to be performed for a child with ALTE and whether there should be a standard work-up. Some patients may not require any investigations because of the low probability of a life-threatening condition, as suggested by a good history and physical exam.²

When the patient’s history and physical examination are insufficient to dismiss the possibility of ALTE, the likelihood of admission rises. Therefore, investigations are helpful in elucidating underlying conditions that may explain the ALTE, but not to rule out an ALTE.

The emergency department work-up can be separated based on suspicion of particular etiologies.

An infant with:

1. Viral symptoms may benefit from a nasopharyngeal swab for viruses.
2. Suspected bacterial infection may benefit from a partial or full septic work-up (although a very small proportion of these patients will have positive findings, and are often younger than 60 days^3,4).
3. Suspected seizure may benefit from an extended electrolyte assessment (i.e., sodium, chloride, potassium, ionized calcium, magnesium, and phosphate).
4. Severe cough may benefit from an Auger suction for pertussis.
5. Suspected respiratory or cardiac involvement may warrant a chest radiograph or electrocardiogram.
6. Tachypnea, altered level of consciousness, failure to thrive, or recurrent vomiting may require investigations for an inborn error of metabolism.
7. Potential neurological etiology may benefit from neuroimaging or electroencephalogram.
8. Suspected intentional or unintentional poisoning may warrant a toxic screen and/or skeletal survey.

GERD

The connection between GERD and ALTE is long debated. It deserves separate discussion, as up to 25% of ALTE admissions can be attributed to it. Whether GERD can lead to SIDS is not yet determined, but the current level of evidence suggests this to be unlikely.⁵ An infant with a history of recurrent vomiting does not yet qualify for the diagnosis of GERD.⁶ Nevertheless, if a history of apnea immediately following vomiting or aspiration is suspected, the diagnosis of GERD is not critical for revealing the cause of the apnea. The diagnosis of GERD is more important in predicting the likelihood of recurrence or allowing targeting of potential therapies.

The probability of SIDS following an aspiration, regardless of GERD, is believed by many clinicians to be extremely low. The evidence for that assumption remains vague because of nonspecific findings on autopsy, both for laryngospasm induced by aspiration and for SIDS, itself. An infant who presents to the emergency department with a history of choking accompanied by facial flushing or breath holding, immediately after or during vomiting, has a high likelihood of aspiration-induced laryngospasm. No physiological compromise seems to have occurred. Therefore, in an otherwise healthy infant, discharge of such infants would appear reasonable. Reassuring the caregivers and ensuring appropriate follow-up is the appropriate and usual disposition for those patients.

Summary

ALTE occurs in up to 1% of infants. The emergency physician’s role in dealing with this entity is challenging, yet critical. While discharging a patient who may have experienced significant apnea is to be avoided, many of the patients who present to the emergency department with an ALTE likely did not experience apnea. Distinguishing those two populations is achieved mainly by taking a detailed history, followed by a thorough physical examination. At this point, most physicians should be able to disposition patients. Investigations that subsequently occur usually serve more to initiate an inpatient work-up for diagnosis and less as part of the decision-making analysis for the disposition of the patient.

References

1. Brand D.A., et al. Yield of diagnostic testing in infants who have had an apparent life-threatening event. Pediatrics 2005;115:885-93.
2. Torrey S.B. Apnea. In: Textbook of Pediatric Emergency Medicine, 5th ed. (Fleisher G.R., et al. (eds)). 2005. Lippincott Williams & Wilkins: Philadelphia, USA.
3. Waseem M., Dubbaka A. Apparent life-threatening event: Is there an increased risk for bacterial infections? Ann. Emerg. Med. 2008;52:S165.
4. Zuckerbraun N.S., et al. Occurrence of serious bacterial infection in infants aged 60 days or younger with an apparent life-threatening event. Pediatr. Emerg. Care. 2009;25:19-25.
5. Arad-Cohen N. et al. The relationship between gastroesophageal reflux and apnea in infants. J. Pediatrics 2000;137:321-36.
6. Puntis J.W., Booth I.W. ALTE and gastro-oesophageal reflux. Arch. Dis. Child. 2005;90:653.

Contributors

Dr. Tavor is in the pediatric emergency medicine academic fellowship program at the Hospital for Sick Children in Toronto. Dr. Mehta is a clinician-teacher in the division of pediatric emergency medicine at the Hospital for Sick Children in Toronto, and is an assistant professor of pediatrics at the University of Toronto. Medical Editor Dr. Robert C. Solomon is an attending emergency physician at Trinity Health System in Steubenville, Ohio, and clinical assistant professor of emergency medicine at the West Virginia School of Osteopathic Medicine.

Disclosures

In accordance with the Accreditation Council for Continuing Medical Education (ACCME) Standards and American College of Emergency Physicians policy, contributors and editors must disclose to the program audience the existence of significant financial interests in or relationships with manufacturers of commercial products that might have a direct interest in the subject matter. Dr. Tavor, Dr. Mehta, and Dr. Solomon have disclosed that they have no significant relationships with or financial interests in any commercial companies that pertain to this educational activity. “Focus on: The ED Management of Pediatric Apparent Life Threatening Events” has been planned and implemented in accordance with the Essential Areas and Policies of the Accreditation Council for Continuing Medical Education (ACCME). ACEP is accredited by the ACCME to provide continuing medical education for physicians. ACEP designates this educational activity for a maximum of one Category 1 credit toward the AMA Physician’s Recognition Award. Each physician should claim only those credits that he or she actually spent in the educational activity. “Focus on: The ED Management of Pediatric Apparent Life Threatening Events” is approved by ACEP for one ACEP Category 1 credit.

Disclaimer

ACEP makes every effort to ensure that contributors to College-sponsored programs are knowledgeable authorities in their fields. Participants are nevertheless advised that the statements and opinions expressed in this article are provided as guidelines and should not be construed as College policy. The material contained herein is not intended to establish policy, procedure, or a standard of care. The views expressed in this article are those of the contributors and not necessarily the opinion or recommendation of ACEP. The College disclaims any liability or responsibility for the consequences of any actions taken in reliance on those statements or opinions.