Basics
Description
- Apparent life-threatening event (ALTE) is an episode that is frightening to the observer and is characterized by some combination of the following:
- Apnea: central or occasionally obstructive
- Color change: usually cyanotic or pallid but occasionally erythematous or plethoric
- Marked change in muscle tone: usually limp
- Choking or gagging
- ALTE describes a presentation rather than a diagnosis and should therefore trigger a pursuit of an etiology.
Epidemiology
- 43% of healthy term infants have at least one 20-second apneic episode over a 3-month period.
- 5.3% of parents recall seeing apnea.
- 0.2-0.9% of infants have an episode of apnea that results in an admission to the hospital.
Risk Factors
- Preterm infants born less than 34 weeks post-conceptual age have higher rates of apnea.
- Differences resolve by 43 weeks post-conceptual age.
- Prematurity, multiple ALTEs, and suspected child maltreatment confer a greater risk for a future adverse event and/or serious underlying diagnosis.
Pathophysiology
- No unifying pathophysiology because of the numerous potential presentations and underlying diagnoses
- Central apnea: disrupted propagation of respiratory signals from the brainstem along the descending neuromuscular pathways. Examples include the following:
- Head trauma
- Congenital central hypoventilation syndrome
- Obstructive apnea: neuromuscular respiratory effort disrupted by an occluded airway. Examples include the following:
- Upper respiratory infection
- Pierre Robin
- Mixed apnea: combination of central and obstructive apnea. Examples include the following:
- Laryngomalacia with a sedating ingestion
- Prematurity with superimposed viral infection
- Color change from decreased oxygenation or differential blood flow. Examples include the following:
- Cyanotic heart disease
- Acrocyanosis
- Altered muscle tone from central or autonomic nervous system disruption. Examples include the following:
- Seizure
- Breath-holding spell
- Choking or gagging: protective response to a stimulation of the airway
Diagnosis
Alert
ALTE is a symptom complex rather than a diagnosis. The practitioner should therefore attempt to identify an underlying diagnosis to explain the presentation.
History
A full, uninterrupted description of the event by a witness may answer or prompt the need to explore the following features:
- Presence of apnea
- Type suggests different causes.
- Obstructive symptoms
- Central symptoms
- Duration may suggest severity: <20-second central apnea is physiologic if not associated with other symptoms such as cyanosis.
- Presence of color change and distribution
- Perioral and peripheral cyanosis are not suggestive of hypoxia unless accompanied by central cyanosis.
- Blue/purple discoloration of face, lips, or core body indicates central cyanosis.
- Change in tone, rhythmic shaking, and/or eye deviation may suggest a seizure.
- Relationship to feeds and/or milk in the mouth may suggest aspiration.
- Fatigue or diaphoresis with feeds may suggest a cardiac condition.
- Coryza may suggest an upper or lower respiratory infection.
- Fever may suggest an infectious etiology.
- History of trauma may suggest an intracranial bleed.
- State of alertness prior to ALTE may suggest sleep apnea.
- Discrepancies among witnesses may suggest nonaccidental trauma.
- Type of resuscitation needed may provide a sense of severity or an opportunity for anticipatory guidance.
- Current condition of child and/or time required to reach baseline: may suggest an ongoing, evolving condition and/or postictal period
- Location of event and position of child (i.e., supine/prone)
- Medications dosed or taken by a breastfeeding mother
- Prematurity
- Prior history of ALTE
- Family history of ALTE, SIDS, or sudden unexpected death
Physical Exam
- Ongoing abnormal symptoms may suggest an evolving and/or underlying condition and should be approached differently than if the patient had a normal exam.
- Arousal
- Vital signs
- Signs of trauma
- Irritability
- Full fontanelle
- Pupil reactivity, conjunctival/retinal hemorrhage
- Bruising or bleeding
- Persisting signs of disordered breathing
- Heart rhythm/murmurs suggestive of an arrhythmia or cyanotic heart disease
- Neurologic exam
- Consider observing a feeding.
Alert
Recurrent ALTEs; historical discrepancies; a family history of ALTE, SIDS, or unexplained death; parents calling emergency services; unexplained facial bruising or bleeding; and the presence or irritability at the time of presentation would warrant a thorough assessment for possible child maltreatment.
Diagnostic Tests & Interpretation
- Routine testing is unlikely to be helpful in patients who are well-appearing and have no other findings suggestive of a particular diagnosis.
- In addition to discomfort, inconvenience, risk, and costs of various tests, an indiscriminate number of screening tests may affect the reliability of the results and initiate an inappropriate and unnecessary testing cascade.
Lab
- If indicated by the history and/or physical
- Basic metabolic panel
- Blood culture
- Cerebral spinal fluid analysis +/- culture
- Complete blood count
- Lactate level
- Newborn metabolic screen
- Urine analysis +/- culture
- Venous blood gas
- Viral studies
Imaging
- If indicated by the history and/or physical
- Airway imaging
- Contrast study of the gastrointestinal tract
- Chest x-ray
- Head CT
- Isotope-labeled milk scan
Additional Testing
- In one study, even though 89% of patients presenting with ALTE had radiographic evidence of GER, half had another diagnosis that was thought to be more consistent with the presentation.
- If indicated by the history and/or physical
- Airway visualization
- Dilated funduscopic examination
- Electrocardiography
- Electroencephalography
- Four-extremity blood pressure
- pH probe
- Sleep study
Differential Diagnosis
Estimated frequency of the involved system given as a percentage
- Gastrointestinal: 34%
- Colic
- Dysphagia
- Esophageal dysfunction
- Gastroenteritis
- GER
- Surgical abdomen
- Neurologic: 17%
- Apnea of prematurity
- Brain tumor
- Central hypoventilation syndrome (Ondine's curse)
- Congenital malformation of the brainstem
- Head injury (intraventricular hemorrhage, subarachnoid hemorrhage)
- Hydrocephalus
- Meningitis/encephalitis
- Neuromuscular disorders
- Seizure
- Vasovagal reaction
- Respiratory: 11%
- Aspiration pneumonia
- Foreign body
- Other lower or upper respiratory tract infection
- Reactive airway disease
- Respiratory syncytial virus
- Pertussis
- Otolaryngologic: 4%
- Laryngomalacia or tracheomalacia
- Anatomic airway stenosis or obstruction
- Obstructive sleep apnea
- Child maltreatment syndrome: 1-2%
- Intentional suffocation
- Munchausen syndrome by proxy
- Shaken baby syndrome
- Head injury
- Ingestion
- Cardiovascular: 1%
- Cardiac arrhythmia/prolonged QTc
- Cardiomyopathy
- Congenital heart disease
- Myocarditis
- Metabolic/endocrine: 1%
- Electrolyte disturbance
- Hypoglycemia
- Inborn error of metabolism
- Other infections: 2%
- Sepsis
- Urinary tract infections
- Other: 6%
- Anemia
- Breath-holding spell
- Choking
- Drug or toxin reaction
- Hypothermia
- Physiologic event (periodic breathing, acrocyanosis)
- Unintentional smothering
- Idiopathic/apnea of infancy: 23%
Treatment
Inpatient Considerations
- Hospital admission is not necessary if the patient is well-appearing and has a self-limited diagnosis to explain the presentation. Admission criteria would include the following:
- Premature patients less than 45 weeks post-gestational age
- Patients with clusters or multiple episodes of ALTE
- Suspected child maltreatment
- If admitted, place on a cardiorespiratory monitor with pulse oximetry.
- Manage patients with persistent symptoms based on the underlying working diagnosis.
Ongoing Care
- All patients should be offered the following anticipatory guidance:
- Safe sleep practices and other SIDS prevention techniques
- CPR overview
Follow-up Recommendations
- Return to medical attention for recurrence.
Prognosis
- Studies on morbidity and mortality are generally incomplete and often contradictory. Differences in reported prognoses from such studies may reflect differences in study design (e.g., patient inclusion criteria, definitions, and follow-up periods, etc.).
- Studies report mortality between 0 and 6%.
- Insufficient data to quantify risk of subsequent event or underlying diagnosis in the asymptomatic patient
- No developmental repercussions among patients who are discharged without a serious underlying diagnosis and have no subsequent events
Additional Reading
- DeWolfe CC. Apparent life-threatening event: a review. Pediatr Clin North Am. 2005;52(4):1127-1146. [View Abstract]
- National Institutes of Health Consensus Development Conference on infantile apnea and home monitoring, Sept 29 to Oct 1, 1986. Pediatrics. 1987;79(2):292-299. [View Abstract]
- Ramanathan R, Corwin MJ, Hunt CE, et al. Cardiorespiratory events recorded on home monitors: comparison of healthy infants with those at increased risk for SIDS. JAMA. 2001;285(17):2199-21207. [View Abstract]
- Tieder JS, Altman RL, Bonkowsky JL, et al. Management of apparent life-threatening events in infants: a systematic review. J Pediatr. 2013;163(1):94-99. [View Abstract]
Codes
ICD09
- 799.82 Apparent life threatening event in infant
- 770.82 Other apnea of newborn
- 770.83 Cyanotic attacks of newborn
- 784.99 Other symptoms involving head and neck
ICD10
- R68.13 Apparent life threatening event in infant (ALTE)
- P28.4 Other apnea of newborn
- R23.0 Cyanosis
- R09.89 Other specified symptoms and signs involving the circulatory and respiratory systems
SNOMED
- 440181000 Apparent life-threatening event (finding)
- 13094009 Apnea in the newborn (finding)
- 95617006 Neonatal cyanosis (disorder)
- 249488009 gagging (finding)
FAQ
- Q: What is the relationship between ALTE and SIDS?
- A: There is no established relationship between ALTE and SIDS. The use of the terms "near-miss SIDS" and "aborted crib death" are discouraged. 4-13% of patients diagnosed with SIDS had a preceding history of apnea, a percentage only slightly higher than healthy controls. The "back to sleep" campaign, which has dramatically decreased the SIDS rate, has had no effect on ALTE presentations.
- Q: What is the role of home monitoring in ALTE?
- A: Home monitors are not efficacious in preventing mortality among patients with ALTE. In fact, there is evidence that caregivers may have increased anxiety, depression, and hostility, whereas patients may have worse developmental consequences. The American Academy of Pediatrics suggests that home monitors may have a role in certain situations such as a known unstable airway, abnormal respiratory control, or symptomatic and technologically dependent chronic lung disease.
- Q: Why aren't there established guidelines with respect to the evaluation and management of patients presenting with ALTE?
- A: No study has compared diagnostic or treatment strategies among first presenters with a sample size large enough to detect rare events in a prospective fashion. Future study of ALTE would be enhanced by applying definitions that could distinguish patient populations.