An event is classified as a BRUE if no cause is found after a thorough history and physical examination and sometimes testing are done.
Known causes, when identified, include digestive, nervous system, breathing, infectious, heart, metabolic, and traumatic disorders.
The diagnosis is based on a discussion with caregivers, a physical examination, and sometimes the results of certain laboratory tests.
The prognosis depends on any identified cause of the event.
Treatment is aimed at specific causes when they can be identified.
Terminology has changed recently. Previously, doctors used the term "ALTE" (apparent life-threatening event) to classify all events where infants suddenly developed alarming symptoms regardless of whether an underlying cause was ultimately found. Currently, if there is no underlying cause, doctors refer to the event as a BRUE (brief, resolved, unexplained event). Some doctors still use the term "ALTE" at first while they are looking for a cause and later if a cause is found.
Although they may seem to be related to sudden infant death syndrome Sudden Infant Death Syndrome (SIDS) Sudden infant death syndrome is the sudden, unexpected death, usually during sleep, of a seemingly healthy infant 1 year of age or younger. The cause of sudden infant death syndrome (SIDS) is... read more (SIDS), there is no clear relationship between SIDS and BRUE or ALTE.
Causes
A cause for the alarming symptoms cannot be determined in more than half of cases. These cases are referred to as BRUEs.
When a cause exists, the most common causes include
Digestive disorders: Gastroesophageal reflux disease Gastroesophageal Reflux in Children Gastroesophageal reflux is the backward movement of food and acid from the stomach into the esophagus and sometimes into the mouth. Reflux may be caused by the infant’s position during feeding... read more or difficulty swallowing Difficulty Swallowing Some people have difficulty swallowing (dysphagia). In dysphagia, foods and/or liquids do not move normally from the throat (pharynx) to the stomach. People feel as though food or liquids become... read more
Nervous system disorders: Seizures Seizures in Children Seizures are a periodic disturbance of the brain’s electrical activity, resulting in some degree of temporary brain dysfunction. When older infants or young children have seizures, they often... read more or brain tumors Overview of Brain Tumors in Children Brain tumors (also see brain tumors in adults) are the second most common cancer in children younger than 15 years of age (after leukemia) and the second leading cause of death from cancer.... read more , breath holding Breath-Holding Spells A breath-holding spell is an episode in which the child involuntarily stops breathing and loses consciousness for a short period immediately after a frightening or emotionally upsetting event... read more , or hydrocephalus Hydrocephalus Hydrocephalus is an accumulation of extra fluid in the normal spaces within the brain (ventricles) and/or between the inner and middle layers of tissues that cover the brain (the subarachnoid... read more
Breathing disorders: Infections with respiratory syncytial virus Respiratory Syncytial Virus (RSV) Infection and Human Metapneumovirus Infection Respiratory syncytial virus infection and human metapneumovirus infection cause upper and sometimes lower respiratory tract infections. Respiratory syncytial virus is a very common cause of... read more , influenza Influenza (Flu) Influenza (flu) is a viral infection of the lungs and airways with one of the influenza viruses. It causes a fever, runny nose, sore throat, cough, headache, muscle aches (myalgias), and a general... read more (flu), or pertussis Pertussis Pertussis is a highly contagious infection caused by the gram-negative bacteria Bordetella pertussis, which results in fits of coughing that usually end in a prolonged, high-pitched,... read more
Infections: Sepsis Sepsis and Septic Shock Sepsis is a serious bodywide response to bacteremia or another infection plus malfunction or failure of an essential system in the body. Septic shock is life-threatening low blood pressure ... read more or meningitis Meningitis in Children Bacterial meningitis is a serious infection of the layers of tissue covering the brain and spinal cord ( meninges). Bacterial meningitis in older infants and children usually results from bacteria... read more
Less common causes include
Heart disorders
Metabolic disorders
Narrowing or complete blockage of the airways (obstructive apnea)
Other disorders (such as drug-related disorders, child abuse Overview of Child Neglect and Abuse Child neglect is withholding essential things from children. Child abuse is doing harmful things to children. Some factors that increase the risk of child neglect and abuse are poverty, drug... read more
, or an anaphylactic reaction Anaphylactic Reactions Anaphylactic reactions are sudden, widespread, potentially severe and life-threatening allergic reactions. Anaphylactic reactions often begin with a feeling of uneasiness, followed by tingling... read more )
Symptoms
A BRUE (or ALTE) usually is characterized by an unexpected, sudden change in an infant’s breathing that alarms the parent or caretaker. Features of an event include some or all of the following:
Not breathing for 20 seconds or more
Color change, usually blue or pale, but sometimes red
Change in muscle tone, usually floppy
Choking or gagging
Diagnosis
A doctor's evaluation
Other testing based on the results of the evaluation
When a BRUE occurs, the doctor asks several key questions:
What was observed by the caregiver who witnessed the event (including a description of changes in breathing, color, muscle tone, and eyes, noises made, length of the episode, and symptoms that occurred before the event)?
What interventions were taken (such as gentle stimulation, mouth-to-mouth breathing, or cardiopulmonary resuscitation [CPR])?
Did the mother use drugs while pregnant? Do members of the family currently use drugs, tobacco, and alcohol?
What was the child's gestational age Gestational age Problems in newborns may develop Before birth while the fetus is growing During labor and delivery After birth About 10% of newborns need special care after birth due to prematurity, problems... read more (length of time spent in the uterus after the egg was fertilized)? Were there any complications at birth? Did the infant remain hospitalized after birth for apnea Apnea of Prematurity Apnea (not breathing) of prematurity is a pause in breathing that lasts for 20 seconds or more in an infant born before 37 weeks of gestation who is not known to have any underlying disorder... read more ?
While feeding, does the child gag, cough, or vomit? Has poor weight gain been an issue?
Has the child reached all age-appropriate developmental milestones Developmental Milestones From Birth to Age 12 Months*
?Has the child had a BRUE before or had a recent injury?
Have there been any other similar events in the family or early death?
The doctor does a physical examination to check for obvious defects, particularly nervous system abnormalities, such as being too stiff (posturing) or being too floppy (poor muscle tone), and signs of infection, injury, or suspected abuse.
Based on the discussion with the caregivers and the physical examination, the doctor may have enough information to ensure the child does not have a serious medical condition. However, if unsure, the doctor may do laboratory tests (blood [including liver tests], stool, urine, and spinal fluid studies), imaging tests (such as a chest x-ray Chest Imaging Chest imaging studies include X-rays Computed tomography (CT) CT angiography Magnetic resonance imaging (MRI) read more or computed tomography [CT] Computed Tomography (CT) In computed tomography (CT), which used to be called computed axial tomography (CAT), an x-ray source and x-ray detector rotate around a person. In modern scanners, the x-ray detector usually... read more 
of the head), electrocardiography Electrocardiography Electrocardiography (ECG) is a quick, simple, painless procedure in which the heart’s electrical impulses are amplified and recorded. This record, the electrocardiogram (also known as an ECG)... read more 
, or a combination of tests based on the infant's examination findings. Other tests to check for possible seizure activity (such as electroencephalography Electroencephalography Diagnostic procedures may be needed to confirm a diagnosis suggested by the medical history and neurologic examination. Electroencephalography (EEG) is a simple, painless procedure in which... read more 
) also may be done.
Prognosis
The prognosis depends on any identified causes. For example, risk of death or disability is higher if the cause is a serious neurologic disorder. A BRUE or an ALTE itself does not seem to have any long-term effects on the child's development.
Although the relationship between a BRUE or an ALTE and SIDS is unclear, children who have had 2 or more events have a higher risk of SIDS.
Treatment
Treatment of identified causes
Sometimes monitoring devices at home
The cause, if identified, is treated. Infants who needed CPR, have had any abnormalities identified during the examination or initial laboratory testing, or whose history is concerning to the doctor are hospitalized for monitoring and further evaluation.
Parents and caregivers should be trained in CPR for infants and in general safe infant care (such as putting infants to sleep on their back and eliminating exposure to tobacco smoke). Doctors sometimes recommend home apnea monitoring devices for a limited period of time. Monitors that can record the infants’ breathing pattern and heart rate are preferred to those that simply sound an alarm. Recording monitors may help doctors distinguish false alarms from real events.
More Information
The following is an English-language resource that may be useful. Please note that THE MANUAL is not responsible for the content of this resource.
Safe to Sleep®: Information for parents and caregivers about safe sleep practices for infants
