An event is classified as a BRUE if no cause of the symptoms is found after a thorough medical evaluation.
Similar symptoms, may be caused by digestive, nervous system, breathing, infectious, heart, and metabolic disorders as well as by physical trauma.
The diagnosis is based on a discussion with caregivers, a physical examination, and sometimes the results of certain laboratory tests.
Treatment is aimed at specific causes, if they are identified.
Sometimes infants have episodes of symptoms that raise concern about their health. Terminology to describe these episodes 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).
BRUE is a term that describes only episodes that occur in children under 1 year of age:
B = Brief: The event lasts for less than 1 minute.
R = Resolved: The event ends and the child returns to a normal state of health.
U = Unexplained: No cause can be found after a doctor's evaluation.
E = Event: The child has symptoms such as changes in breathing or a period of no breathing (apnea), a change in color, a change in muscle tone, and/or a change in the level of responsiveness.
Such episodes 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 between 1 month and 1 year of age. The cause of sudden infant death syndrome... read more (SIDS), but most infants with SIDS did not have any type of alarming event beforehand. However, infants who have had 2 or more BRUEs appear to be at an increased risk of SIDS.
Symptoms of BRUE
A BRUE is characterized by an unexpected, sudden change in an infant that alarms the parent or caregiver.
Features of a BRUE that may alarm a parent or caregiver include some or all of the following:
Breathing that stops for 20 seconds or more (apnea), breathing that is irregular, or no breathing at all
Color change, blue or pale
Change in muscle tone, too stiff or floppy
Change in the level of responsiveness (for example, drowsiness, inactivity, loss of consciousness)
A cause for the alarming symptoms cannot be determined in more than half of cases. Therefore, these cases are referred to as BRUEs.
Causes of symptoms similar to BRUE
By definition, a BRUE is an episode with no known cause. In some cases, a cause for the symptoms is identified during a medical evaluation.
When a cause exists, the most common possible 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 and Spinal Cord Tumors in Children The central nervous system is made up of the brain and spinal cord. Central nervous system tumors are the second most common cancer in children under 15 years of age (after leukemia) and the... 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 possible 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 maltreatment includes all types of abuse and neglect of a child under the age of 18 by a parent, caregiver, or another person in a custodial role (for example, clergy, coach, or teacher)... 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 )
Diagnosis of BRUE
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 take medications or use recreational 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 9% 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 abnormalities, 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 uncertain, the doctor may do laboratory tests (such as blood tests to check for anemia or infection and tests for kidney and liver function, as well as 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) Computed tomography (CT) is a type of medical imaging that combines a series of x-rays to create cross-sectional, detailed images of internal structures. In computed tomography (CT), which used... 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. Imaging tests commonly used to diagnose nervous system (neurologic) disorders... read more 
) also may be done.
Treatment of BRUE
Treatment of identified causes
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 do not recommend using at-home breathing monitors as a way to reduce the risk of SIDS. There is no evidence that these monitors reduce the risk of SIDS. They are not substitutes for following recommended safe sleep measures Prevention Sudden infant death syndrome is the sudden, unexpected death, usually during sleep, of a seemingly healthy infant between 1 month and 1 year of age. The cause of sudden infant death syndrome... read more .
Prognosis for BRUE
The prognosis depends on any identified causes. For example, risk of death or disability is higher if the cause is a serious neurologic disorder.
Although the relationship between a BRUE and SIDS is unclear, children who have had 2 or more BRUEs have a higher risk of SIDS.
More Information
The following English-language resource 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
