Download An Apparent Life-Threatening Event (ALTE) is an episode

An Apparent Life-Threatening Event (ALTE) is an episode that frightens a child’s caretaker. These events
can involve any of the following:
 Apnea
 Color change (cyanosis, pallor, erythema, plethora)
 Marked change in muscle tone (limpness)
 Choking or gagging
These events usually occur in infants less than 12 months old, but ALTE should be suspected in any child
less than 2 years of age who displays these symptoms.
Most patients will appear stable and may have a normal physical exam by the time field personnel arrive.
Despite their appearance, some of these patients will be later diagnosed with conditions that may require
further medical care.
PURPOSE
 To increase awareness of the risks of Apparent Life-Threatening Events, and to encourage the transport
of patients who have suffered symptoms of an ALTE.
TREATMENT
 Provide routine pediatric medical care.
 Assume the history given is accurate.
 Obtain a description of the severity, nature, and duration of the event.
Any known chronic illnesses?
Evidence of seizure activity?
Current or recent infections?
History of gastroesophageal reflux (spitting, vomiting)?
Inappropriate mixture of formula?
History or evidence of recent trauma?
Medications? (current and recent), including over the counter drugs
Associated events (eating, crying, etc.)
Complete a comprehensive physical exam. Include evaluation of the child’s appearance, skin color, and
interaction with the environment and parents.
Check for any evidence of trauma.
Treat any identifiable injuries/illnesses.
Transport.
 If the parent or guardian refuses medical care and/or transportation, make base contact with the Base
Hospital Physician prior to completing an AMA form and leaving the scene.
Background:
In some cases, the observer fears that the infant has died. Previously used terminology, such as "aborted
crib death" or "near miss SIDS" should be abandoned as it implies a, possibly, misleading close association
between this type of spell and SIDS.
This definition encompasses a broad range of behaviors and potential diagnoses. In most cases, the
emergency physician will be examining a well-appearing infant who has experienced an ALTE prior to
arrival at the ED or an infant who has home apnea and bradycardia monitoring with a history of frequent
monitor alarms. The challenge lies in using the history provided by the caretakers to make a presumptive
diagnosis and an appropriate referral.
Pathophysiology: ALTE is not so much a specific diagnosis as a description of an event.
There are several potential causes for such an event. These include central apnea, obstructive apnea,
gastroesophageal reflux (GER), cardiac arrhythmia and seizure disorder. ALTE is also a common
complaint for parents who are perpetrators of Munchausen's syndrome by proxy and may be a
secondary manifestation of certain types of child abuse. Apnea may be a part of the presentation of
infants with sepsis and other severe illnesses. However, these infants will not be well appearing and a
discussion of the management of such patients will be reviewed at a later lecture.
The cause of central apnea is unclear. Certain drugs are known to cause central apnea but, in most cases,
there is no history of drug exposure. It is important for the examining physician to ask about maternal illicit
drug use, particularly when the infant is breast-fed or when smokeable substances are possibly being used.
Carbon monoxide poisoning must be considered, as young infants are more likely to be affected than adults
are due to fetal hemoglobins.
The usual cause of central apnea is often presumed to be immaturity of the respiratory center, with a
weaker respiratory response to hypercapnia. Studies of patients followed in apnea centers have shown
increased respiratory pauses compared to age-matched controls. However, there appears to be no
correlation between these events and lower levels of oxygen. Studies of hypercapnia in infants with known
apnea have failed to demonstrate an abnormal response to CO2.
Obstructive apnea may occur for several reasons. Some infants have laryngomalacia or tracheomalacia. In
these cases a thin, floppy upper airway and trachea, which is prone to collapse during the negative pressure
of inspiration. Such infants are prone to stridorous breathing.
Obstructive apnea may also occur as a result of gastroesophageal reflux (GER). Although apnea from GER
usually has another cause, in some cases, GER causes laryngospasm and obstructive apnea. Infants with
severe GER may have apnea due to stimulation of chemoreceptors around the larynx. This results in central
apnea, bradycardia and pallor. In older patients with GER, ALTE is more likely to result from laryngospasm.
Cardiac arrhythmias cause ALTEs for obvious reasons. Infants with prior cardiac surgery or known
congenital defects in the vicinity of the conducting system are possible victims but, in most cases, the
causes for the arrhythmia are obscure. The infant with a cardiac cause for ALTE is less likely to present with
primary apnea.
Neonatal seizures are often quite different from those seen in older children. While apnea may result from
seizures, it is usually not the only symptom. Most patients with seizures also have abnormal movements or
posturing, and lateralizing eye movements.
Apnea and ALTE are also seen as a result of child abuse and should be considered in cases of infants who
are not well appearing on arrival. Munchausen's syndrome by proxy may be suspected in the infant who has
recurrent or bizarre ALTEs, particularly when the family has been to several EDs and physicians with the
same complaint and "no one can find the cause". A previous SIDS death in the same family also increases
the risk of Munchausen's by proxy.
Frequency:
 In the US: Estimates of the incidence of ALTE range from 0.5-6% in the general population. However,
the studies upon which these estimates are based have methodological flaws, which make them hard to
interpret.
 Internationally: The worldwide incidence of ALTE is unknown. One report from Sweden places the
incidence of apnea during the first 4 d of life at 0.35/1,000 population.
Mortality/Morbidity:
 There are studies that suggest 5-10% of victims of SIDS have had a previous ALTE. Eight studies of
mortality among patients with a history of ALTE place the death rate at 1% with some, but not all,
patients dying of SIDS. On the other hand, it is well recognized that most victims of SIDS have not had a
prior ALTE.
Sex:
Data on this subject are variable but most studies demonstrate a male predominance. In some studies the
male to female ratio among infants with ALTE is as high as 2:1.
Age:
The average infant presenting after an ALTE is 8-14 wk. About 7% of these infants were born prematurely.
History:
In most cases, the child will have been seen to change colors and/or stop breathing or will have been found
limp by the caretakers. Additionally, he/she may have experienced a significant episode of coughing,
choking, or gagging.
Physical:
In the vast majority of cases, the infant appears well and the examination will be entirely normal. Infants
who are not well appearing may have a variety of serious disorders (see Differential Diagnosis, below) so it
is most important to identify infants who look sick.
Causes:
 Bacteremia and Sepsis
Bronchiolitis
Sudden Infant Death Syndrome
Other Problems to be Considered:
Well Child, Anxious Mother (diagnosis of exclusion)
Child Abuse (Munchausen's by proxy)
Status Epilepticus and Seizure Disorders
Dysrhythmias
Cardiac Congenital Malformations
If the infant is truly well afebrile and well appearing, laboratory studies are likely to be normal.
If the infant is not well appearing or if assessment is impossible due to age, the following studies should be
considered:
Complete blood count (CBC) with differential
Electrolytes
Lumbar puncture
Urinalysis
These tests will identify the presence of an unexplained metabolic acidosis and help to identify the
potentially septic infant or the infant with unexplained anemia.
Additionally, the combination of hyperkalemia and hyponatremia may be the first suggestion of congenital
adrenal hyperplasia in the male infant.
When the clinical presentation warrants, a carboxyhemoglobin level, methemoglobin level and a screen for
certain toxins (e.g., cocaine) should be considered.
If the infant has a history of central apnea, he/she may be on theophylline or caffeine, which stimulates the
central respiratory centers. Therefore, levels of these drugs to document therapeutic levels and/or
compliance, may be helpful.
Imaging Studies:
In most cases no imaging studies are needed.
In those cases where raised intracranial pressure or intracranial hemorrhage is suspected a heed CT scan
is indicated.
In premature infants a head CT scan may reveal intraventricular and periventricular hemorrhages.
When child abuse is being seriously considered, a skeletal survey should be obtained. Other Studies: A
neurologists may request admission for an EEG.
Prehospital Care:
Prehospital care of the infant with an ALTE includes resuscitation, if necessary, and monitored transport to
an ED.
If the infant has an apneic event during transport, prehospital personnel should first attempt simple manual
stimulation of the infant.
Brisk rubbing along the back, patting and thumping the feet may be tried.
If these maneuvers fail, artificial ventilation should be initiated.
Emergency Department Care:
In the ED, all infants who have sustained an ALTE should have cardiac and respiratory monitoring.
Ill-appearing infants should be treated as needed based upon their clinical condition.
This may include resuscitation or treatment of sepsis.
Well-appearing infants may need no emergency treatment other than a careful history and physical
examination.
Consultations:
Consultation is most important for those patients who are on home monitoring. Most of these children are
followed by a special apnea service.
Such services may be helpful by providing important historical data about the patient. Also, they often
facilitate contact with the company providing the monitoring service.
Additionally, the apnea service may be able to simplify the process of admission or transfer to a tertiary care
pediatric facility.
Further Inpatient Care:
Most children who have sustained an ALTE should be admitted for treatment of their underlying medical
problem, or for a diagnostic evaluation.
The diagnostic evaluation of the child with ALTE usually includes a multichannel study.
The infant is observed for an extended period of time while monitors record data (e.g., EEG, ECG,
esophageal pH probe, chest movement monitor and a nasal airflow monitor).
Such monitoring requires some expertise and is probably best conducted in a pediatric center.
Outpatient Care
There are 3 types of children who may be safely discharged for further outpatient management.
If the history suggests that the family misinterpreted a normal episode of periodic breathing
The infant/child is well appearing in the ED
If the infant had no color change and is not seen to have frequent episodes of periodic breathing during a
reasonable period of monitored observation
Similarly, if the history suggests an isolated choking episode in an infant who feeds aggressively, the child
may be discharged. The parents of such children should be instructed to interrupt feeding more
frequently and to burp their infant often.
Outpatient Care
Transfer:
Most infants who have an ALTE should be evaluated in a facility with expertise in the diagnostic evaluation
of such patients.
The team transporting the infant should be capable of monitoring and, if necessary, resuscitating an infant. If
available, a pediatric transport team is an excellent choice.
The relationship between ALTE and SIDS is unknown. Certainly, some infants who have ALTEs would have
died had they not been found in time.
One complication, which is often ignored, is the psychological impact of home monitoring upon the family.
Monitoring places a tremendous amount of pressure on the caretakers. Families deal with these pressures
in many ways.
Some parents eventually stop using the monitor while others become dependent upon it.
Some families experience renewed fears when they are told that their child no longer requires home
monitoring.
Many of these stressors may be manifested in the ED.
It is not hard to imagine the parents of a child about to have his/her home monitor discontinued presenting
to the ED with a complaint of frequent alarms in hope of having the period of monitoring continued.
Prognosis:
Most children who survive an ALTE and are placed on home monitoring do well.
In general, as the child matures, the cause of the ALTE is diagnosed and treated or spontaneously resolves.
Patient Education:
Parents of infants who are discharged should be instructed to return if:
more episodes occur,
episodes become associated with color change, or
new and/or worrisome findings (such as fever, lethargy, or frequent vomiting) develop.
Infants who have had a choking episode should receive feeding instructions as described above.
Families of monitored infants should be reminded to maintain current CPR training.
It is far better to err on the side of admission of most of these infants.
Even though the baby is well appearing at the time of ED evaluation, he or she may have had a significant
episode.
Only those infants who have had a single episode of periodic breathing not associated with color change, an
isolated and explainable choking episode or an unequivocal mechanical problem with a home monitoring
device, should be considered candidates for discharge.
Special Concerns: Cyanotic Heart Disease
Tetralogy of Fallot
Transposition of the great vessels
Truncus arteriosus
Total anomalous pulmonary venous return
CME Question 1: A well-appearing infant is brought to the emergency department by his/her parents. The
parents state that the child "turned blue". All EXCEPT which one of the following are likely diagnoses?
A: Central apnea
B: Overwhelming sepsis
C: Cardiac arrhythmia
D: Gastroesophageal reflux
E: Seizure disorder
The correct answer is B: The other 4 conditions that are listed may cause a well-appearing infant to have an
ALTE. The infant with sepsis is unlikely to be well appearing.
CME Question 2: More unusual causes of an apparent life-threatening event (ALTE) include all of the
following EXCEPT?
A: Munchausen's syndrome by proxy
B: Carbon monoxide poisoning
C: Inhalation of smokeable drugs of abuse
D: Central (idiopathic) apnea
E: Ingestion of toxins
The correct answer is D: Central apnea, sometimes called idiopathic central apnea, is a common cause of
ALTE. The other entities are much less common.
Pearl Question 1 (T/F): A mother was holding her 6-month-old male child when he suddenly assumed a
strange posture. The mother reports that he had stiffening and extension of his right arm and that his head
turned to the right. This was associated with a "blue spell." The most likely cause is gastroesophageal
reflux.
The correct answer is False: Seizures would be the most likely cause of an ALTE associated with an
unusual posture or abnormal movements.
Pearl Question 2 (T/F): The relationship of ALTE to sudden infant death syndrome is well understood?
The correct answer is False: The relationship is unknown. Only a fraction of the infants diagnosed with
ALTEs go on to die of SIDS.
Pearl Question 3 (T/F): A careful history will often reveal the cause of ALTE.
The correct answer is True: A careful medical history is the best way to make a presumptive diagnosis.
Sophisticated (and expensive) testing can be employed judiciously when the examining physician has done
a good history.
Pearl Question 4 (T/F): A newborn infant is brought into the Emergency Department because he "stopped
breathing." During your physical examination, the mother screams "Oh my God, he's doing it again." You
note no color change. The episode lasts 8 seconds (by your watch) after which normal breathing resumes.
The most likely diagnosis is a normal respiratory pause.
The correct answer is True: The most likely diagnosis is normal periodic breathing. Normal infants have
respiratory pauses lasting up to 20 seconds. These are nothing to be alarmed about unless they are very
frequent or prolonged.