BRUE in Babies: A Comprehensive Guide for Worried Parents

If your child appears to be ill, there is usually a specific cause for their symptoms.

There are some incidents, however, that can’t be explained so easily, and if this is the case for your baby, a doctor may diagnose a BRUE in your child.

A BRUE is a brief, resolved, unexplained event that typically occurs in infants under 12 months. A BRUE can be a frightening but transient event (less than a minute) with no clear underlying cause in more than half of cases. Symptoms include a change in breathing, color, muscle tone, and responsiveness.

To understand more about BRUE in babies, we’ve compiled a full guide that aims to answer many of your most pressing concerns from the common age and risk factors for BRUE to treatment and how to respond during a BRUE event.

What Qualifies as a BRUE?

An episode can be classed as a BRUE (brief, resolved, unexplained event) if doctors cannot find an underlying cause of the presenting symptoms after a thorough medical evaluation

In a 2016 update of the AAP’s guidelines (American Academy of Pediatrics), the term BRUE replaced the term ALTE (apparent life-threatening event).

ALTE was the terminology used by doctors to catalog all events in which infants developed a sudden onset of alarming symptoms regardless of whether an underlying cause was discovered.

According to pediatrics specialist Christopher P. Raab at Thomas Jefferson University, PA, the updated term BRUE requires the infant to be less than 12 months old, the event to have no other likely explanation (unexplained by medical history), and the diagnosis to be based on a clinician’s assessment of the event and not the caregiver’s perception of a life-threatening event.

BRUE Criteria

The criteria for BRUE (brief, resolved, unexplained event) in children is as follows:

B = Brief: Episodes usually last less than a minute.

R = Resolved: Following the brief event, the child returns to a normal state of health.

U = Unexplained: A cause cannot be found after a doctor’s evaluation.

E = Event: The child presented symptoms such as a change in their breathing, color, responsiveness, or muscle tone.


Broadly, the age range for the occurrence of BRUE is in infants less than 60 days old and up to as late as 12 months old.

Using the previous terminology ALTE as a guide, research conducted by pediatric critical care nurse Susan Porth found that events peaked at less than 60 days old.

A 2019 study of BRUE appears to mirror this peak period referred to by Porth with findings that 94 percent of infants who experienced a BRUE were hospitalized before 6 months of age.

High-Risk BRUE

High-risk BRUE is usually present in:

  • Infants younger than 2 months (roughly 60 days old)
  • Infants with a history of prematurity (with the risk being higher in less than 32 weeks gestation)
  • Infants experiencing more than one of the events mentioned (i.e., color change AND a change to their breathing)
  • Those with a family history of sudden death or infant death

According to authors Kondamudi and Virji of the Brooklyn Hospital Center and the University of British Columbia, patients are automatically considered high-risk if they do not meet the criteria for low-risk BRUE.

Unlike low-risk cases, babies with high-risk BRUE will require a thorough physical exam to identify the trigger.

Low-Risk BRUE

Babies with low-risk BRUE are often found to:

  • Be older than 60 days
  • Have a gestational age of 32 weeks or older
  • Have a post-conceptional age (gestational plus natal age) greater than/equal to 45 weeks

Furthermore, the event and aftercare in low-risk BRUE usually adhere to the following:

  • This was the first brief, resolved, unexplained event, i.e., no previous BRUE and the event was singular (didn’t occur in clusters)
  • The event itself lasted less than 1 minute
  • No CPR was required
  • There were no concerning historical characteristics or findings after a physical examination.
A doctor using a stethoscope to listen to a baby's heart.

BRUE Symptoms

BRUE in infants typically consists of four main symptoms:

  • Apnea: Breathing becomes irregular, decreased, or absent (breathing that stops for 20 seconds or more)
  • Cyanosis or Pallor: A change in their color, turning pale or blue
  • Hypo or Hypertonia: A change in muscle tone, becoming too stiff or too floppy
  • Change in responsiveness: Drowsy, inactive, loss of consciousness

How Is BRUE Diagnosed?

A diagnosis of BRUE is made if no known concerning cause has been found to explain the event or events after your baby has been medically examined or after the results of any testing based on the initial evaluation have been inconclusive.

A BRUE diagnosis can be further confirmed if, in combination with the above, there is no appropriate medical history to explain the symptoms.

BRUE Causes

By definition, a BRUE is an event with no definitive cause, and in healthy children who only have one event, the cause is rarely identified.

Though when a cause is found, according to the Texas Children’s Hospital, the most commonly reported causes are linked to gastroesophageal reflux (GER/GERD), seizures, and lower respiratory tract infections (LRTI) such as pneumonia or bronchiolitis.

BRUE can also occur with metabolic and cardiac disorders, though more than 50 percent of BRUE cases are considered idiopathic (arising spontaneously from no known cause).

As reported by Perth Children’s Hospital in their table of differential diagnoses for BRUE, lower respiratory tract infections account for 7-8% of incidents, and 4-11% of seizures in BRUE can have an underlying neurological cause.

Can GERD cause BRUE?

GERD or GORD (gastroesophageal reflux) is thought to account for 20-50% of BRUE incidents and presents with symptoms of choking or gagging in the infant caused by an exaggerated airway protection reflex known as laryngospasm.

A laryngospasm can be triggered by choking or vomiting during a feed, which can lead to BRUE-like symptoms (change in color, apnea, etc.).

Typically no testing is done in infants with a suggested GERD event, but those with repeated choking episodes may require an evaluation of their swallowing ability.

BRUE Risk Factors

The main risk factors for BRUE in babies include:

  • Feeding issues (difficulty swallowing, choking on food or liquid)
  • Infants younger than 10 weeks
  • Infants who have suffered recent head colds or bronchitis
  • Infants with a prior episode of absent breathing, turning pale, or having blue coloring
  • Reflux
  • Swallowing too much medicine or accidentally swallowing other substances
  • Seizure disorders
  • Heart conditions
  • General anesthesia from a recent surgery

Additional BRUE risk factors are thought to be:

  • Low birth weight
  • Child abuse
  • Recent head injury
  • Exposure to second-hand smoke

BRUE Treatment

In cases with a concerning medical history, those who required CPR, or those thought to have had abnormalities identified during examination, infants are normally hospitalized and monitored for evaluation.

There is no medication or specific testing in the aftermath of a BRUE.

Rather, an essential part of the treatment and management of BRUE lies in educating the parents/caregivers about the condition, urging follow-up care, and perhaps providing resources on CPR training.

Safe infant care tips such as eliminating their exposure to cigarette smoke and practicing safe sleep guidelines as outlined by the AAP may reduce the risk of BRUE-like conditions.

How Common Is BRUE?

According to Perth Children’s Hospital, the occurrence of BRUE when it was previously described as ALTE (apparent life-threatening event) was around 1 in every 1,000 live births.

BRUE (when termed ALTE) has also accounted for approximately 0.6% to 0.8% of all emergency department visits, according to research by Kondamudi & Virji.

How Long Does a BRUE Last?

A BRUE typically lasts less somewhere between 30 and 60 seconds and rarely lasts longer than a minute.

When a BRUE occurs, the inevitable fear and panic that comes with seeing your baby in this way can make it hard to determine how long the BRUE may have lasted.

All you can do is describe the event in as much detail as possible, including how recent their last feed was, position, sleeping/awake, etc., to your doctor so they can make a rounded assessment.

Can Babies Die From BRUE?

According to the National Library of Medicine, BRUE is most often harmless and not an indicator of severe health problems or death.

The risk of death or disability from a BRUE tends to be higher if a serious neurological disorder is the cause.

A 2018 study in the Journal of Pediatrics found the rate of death in infants following a BRUE to be relatively rare, accounting for 1 in every 800 cases.

A separate study into the long-term follow-up of infants after a BRUE found that low-risk infants who were hospitalized generally appeared to have an excellent prognosis.

Can a BRUE Happen More Than Once?

Assuming babies are otherwise healthy with no underlying medical issues, a large number do not go on to experience a second BRUE or complications and will go on to develop normally according to Dr. Raab.

In any case, it’s essential to inform your healthcare provider of the BRUE as they may decide to observe your baby in a hospital in case a second BRUE occurs.

To be on the safe side, Nationwide Children’s Hospital advises scheduling a follow-up appointment with your child’s primary healthcare provider within 48 hours of a BRUE.

A red-headed baby asleep without a shirt and with his arms raised over his head.

Is BRUE Related to SIDS?

No. BRUE is not related to SIDS (Sudden Infant Death Syndrome) or older terms for SIDS such as “near-miss SIDS.”

It is important to note, however, that infants who have experienced two or more BRUE incidents can be at a higher risk for SIDS.

While BRUE and SIDS share similar possible causes including being premature, exposure to second-hand smoke, etc., the majority of infants with SIDS did not have any alarming events beforehand.

BRUE vs. Seizure

A BRUE event can be suggestive of a seizure since some of the main symptoms of a BRUE are muscle rigidity, limpness, or twitching.

Alongside hypertonia (change in muscle tone) a true seizure will normally also consist of jerking limbs, repeated spasms, twitching lips, staring, blinking, eyes rolling in the back of the head, and other symptoms.

Infants deemed as low-risk BRUE will not normally benefit from further testing, especially if this is a first-time seizure.

However, if your healthcare provider believes this seizure-like activity to be a cause for concern, CNS imaging (non-invasive imaging of the central nervous system) or an EEG (a painless recording of brain activity) could be suggested, according to Emergency Physicians Monthly.

What To Do During a BRUE?

During a BRUE it is essential to:

1. Attempt to get your baby to respond


2. Stay calm while holding them

Firstly, try to get him or her to respond by rubbing their back, hands, or feet or calling their name loudly.

If your baby does not respond to any of these methods or has stopped breathing, immediately call 911, and an operator will guide you through what to do next.

A second crucial point is to try and remain calm while you are near/holding your baby.

This may sound easier said than done under the circumstances, but a panicky nature may lead you to accidentally shake your baby in an effort to rouse them or help them breathe.

This could result in shaken baby syndrome, leading to potential blindness or brain damage, so try to remain as calm as possible.

BRUE Prevention

A BRUE happens so suddenly, and most are without cause, so prevention can be difficult. There are preventative measures you can take to help reduce your baby’s risk though, such as:

  • Ensuring safe sleep practices as approved by the AAP
  • Eliminating their exposure to any tobacco smoke
  • Practicing reflux precautions – feeding them in small amounts, burping often after/between feeds, keeping them upright for a time after feeding, etc.
  • Preventing feeding issues – speak to your child’s physician about any swallowing issues they may have such as dysphagia.
  • Learning infant CPR – you can ask your healthcare provider about taking infant CPR classes whether your child has experienced a BRUE or not. (Note: you will need to take a separate infant CPR class even if you already know adult CPR).

Closing Thoughts

In summary, a BRUE in babies stands for a brief, resolved, unexplained event.

Though fleeting, this event can present alarming symptoms that include stiff or floppy muscles, pale coloring, a change in breathing patterns, or unresponsiveness.

BRUE is thankfully mostly harmless, and in many cases, an underlying cause cannot be determined.

Remember that it’s essential to have your baby examined within 48 hours of a BRUE incident in case of a second event, and please don’t hesitate to speak to your child’s care physician if you have any concerns about their risk factors for BRUE.