Brief, Resolved, Unexplained Events and Sudden Infant Death Syndrome

Lourdes M. DelRosso, MD, and Lee J. Brooks, MD, FAAP

Brief, Resolved, Unexplained Events (Formerly Apparent Life-Threatening Events)

Introduction

•A brief, resolved, unexplained event (BRUE) is defined as an episode that occurs in an infant <1 year of age and is reported by the observer as a sudden, brief, and now-resolved episode that included ≥1 of the following:

—Color change (cyanosis or pallor)

—Change in breathing (absent, irregular, or decreased)

—Change in muscle tone (hypertonia or hypotonia)

—Altered level of responsiveness

•Previously, an apparent life-threatening event (ALTE) was defined as an episode that was frightening to the observer and was characterized by some combination of apnea, color change, marked change in muscle tone, choking, or gagging. In some cases, the observer believed the infant had died.

•In 2016, the American Academy of Pediatrics (AAP) proposed the use of BRUE instead of ALTE in infants when there was no explanation for the event after obtaining a history and performing a physical examination.

•To date, there has been little specific research on the new BRUE terminology; most of the following guidelines apply to studies of ALTE.

Etiology

Figure 97-1. Etiologic origins of apparent life-threatening events. GERD = gastroesophageal reflux disease, RSV = respiratory syncytial virus.

•Less common causes are hypoxemia, sepsis, anemia, long QT syndrome, and child abuse.

•The respiratory infections found are often bronchiolitis, pertussis, or lower respiratory infections.

•Child abuse has been detected in 2.3% of infants who present to the emergency department with ALTE.

•The cause of ALTE is not found in 50% of cases.

Epidemiology

•The incidence of BRUE has not yet been clearly established.

•Previously, the incidence of ALTE was estimated at 0.6 per 1,000 live births, with a peak incidence during the first 2 months of life.

•Risk factors include the following.

—Premature infants have twice the risk of the general population for ALTE. This may be secondary to immature central control of breathing and airway reflexes.

—Upper respiratory infection

—Exposure to smoking

—History of recent anesthesia

Pathophysiology

•There are diverse pathophysiological contributors to ALTE.

•Apneic causes can be secondary to immature breathing centers. Apneic episodes could be central, obstructive, and periodic breathing.

•GERD is the most common diagnosis identified in infants with ALTE, but gastroesophageal reflux is also common in all infants. Causality is therefore difficult to prove.

•ALTE has been reported while the infant is in the car seat, likely because of airway obstruction that occurs during cervical flexion.

Clinical Features

•The infant usually presents with a sudden change in behavior that alarms the caregiver.

•The most common presentations include loss of muscle tone, color change (usually pallor or cyanosis), arrest of breathing, choking, and gagging.

•The event may end spontaneously or may require parental intervention.

•Parental intervention ranges from position change (picking up the infant) and vigorous stimulation to cardiopulmonary resuscitation (CPR).

•The infant may or may not present with signs of acute illness.

Diagnostic Considerations

•A detailed clinical history must include

—The description and duration of the event: Did the event occur while the infant was asleep or awake? Was there a skin color change? Was the infant limp or rigid? Descriptions from all witnesses are helpful.

—Description of the postevent recovery: Did the infant recover spontaneously? Did the infant require gentle or vigorous resuscitation? Was CPR performed?

—Was the child completely healthy before the symptoms occurred, or were there symptoms of other illness?

—Account of previous similar events

—Birth history and gestational age

—Feeding history: Vomiting, weight gain, choking

—Comorbidities: Seizures, metabolic disorders, cardiorespiratory status — Medications

—Recent injury or trauma

—Social history: Parental smoking or drug use or history of report of possible child abuse in the past

—Family history: Similar episode in a sibling or a sudden unexpected death in a relative

• Physical examination

—Height, weight, and head circumference

—Vital signs, including pulse oximetry

—Complete and detailed physical examination

—Funduscopic examination may aid in the detection of trauma.

—Routine laboratory testing is not indicated if the event was mild or if a diagnosis is identified via the history and physical examination.

—Further laboratory evaluation should be directed by the history and physical findings.

—For severe reported cases or when the physical examination findings do not indicate a diagnosis, evaluation may include

▪Cardiorespiratory monitoring in the emergency department

▪Blood tests (complete blood count, glucose and electrolyte levels, toxicology assessment, blood culture, lactate level, Bordetella pertussis and respiratory syncytial virus testing)

▪Lumbar puncture

▪Esophageal pH level and manometry monitoring

•Imaging

—Chest radiography

—Brain computed tomography or magnetic resonance imaging

• Polysomnography is indicated if obstructive apnea is suspected.

• No single study has a high predictive value for diagnosis of an underlying condition.

Management

•Care of the infant with a BRUE or ALTE should start during the event. This should include stimulation of the infant and CPR if needed.

•Management should be individualized, because the clinical presentation can be secondary to various underlying conditions.

•Infants with history of multiple BRUEs or ALTEs, with clinically significant symptoms at the time of evaluation (fever, respiratory distress, evidence of trauma, etc) or with clinically significant compromise during the event (sustained cyanosis, requiring resuscitation), may require hospitalization.

•When an underlying condition is evident (ie, infection), the condition should be treated promptly.

•Home cardiorespiratory monitoring may be indicated. Cardiorespiratory monitors do not prevent apnea or bradycardia, but they alert the family to the presence of an event so they can intervene. If home monitoring is chosen, all caregivers must be trained on how to respond to alarms, up to and including CPR.

•Stable, low-risk infants may be discharged from the emergency department if

—The patient experienced only 1 event

—The event was brief

—The infant recovered spontaneously

—The history and physical examination findings are normal

—Those >60 days old

—Gestational age ≥32 weeks and postconceptional age ≥45 weeks

—No history of prior BRUE

—BRUE duration of <1 minute

—CPR not required

—No concerning history or physical examination findings

•Management strategies for these infants include

—Parental education

—Follow-up arrangement and shared decision about future evaluation

—CPR training

—Potential pertussis testing and 12-lead electrocardiography

—Possible brief monitoring of continuous oximetry and serial observations

When to Admit

•Admit infants who have recurrent episodes without an explanation.

•Admit infants with a clear diagnosis who are unstable—that is, infants who require ventilation or intravenous antibiotics.

•Admit infants without a clear diagnosis but with an abnormal history or physical examination findings that require further inpatient evaluation.

•Admit infants with clinically significant compromise (a prolonged event that requires CPR).

Expected Outcomes/Prognosis

•Most infants with BRUE or ALTE will proceed to have a benign course without any long-term sequelae.

•Only 12% of infants will require admission for further evaluation.

•Up to 24% of infants will have a recurrent episode.

•A history of prematurity and recurrent events is associated with a higher probability of finding an occult condition.

•In about 50% of infants, a careful history and physical examination findings will indicate a diagnosis.

•There is insufficient evidence to estimate the risk of a subsequent event or the presence of an underlying diagnosis in infants who are asymptomatic.

Prevention

•If there is a pulmonary concern in a premature newborn, establish whether travel in a car is safe before hospital discharge. The newborn may be observed in his or her own car safety seat for 90–120 minutes or the anticipated length of the trip to be monitored for desaturation, apnea, or bradycardia. Parents should be educated about proper positioning.

•Avoid exposure to smoking. Recommend smoking cessation to parents and caregivers.

•Promote safe sleep practices, including supine positioning, the use of a firm sleep surface, and the avoidance of soft bedding and overheating.

•Parents should be educated about CPR.

•Consider home cardiorespiratory monitoring for

—Severe ALTE

—Infants with vulnerable airway (tracheostomy)

—Technology-dependent infants, such as those requiring mechanical ventilation

—Infants with symptomatic chronic lung disease, especially those requiring oxygen or those who have experienced an ALTE

—Home monitoring can relieve anxiety for some parents and heighten anxiety in others, so monitors should only be prescribed after careful consideration of risks and benefits.

Sudden Infant Death Syndrome

Introduction

•Sudden infant death syndrome (SIDS) is defined as the sudden death of any infant <1 year of age, which remains unexplained after a thorough case investigation, including performance of a complete autopsy, examination of the death scene, and review of the clinical history.

•SIDS and accidental sleep-related suffocation are the most commonly reported types of sudden unexpected infant death (SUID).

Etiology

•The etiologic origins are unknown but are postulated to be related to a combination of factors.

—Apnea of prematurity is not necessarily a precursor of SIDS.

—BRUE or ALTE is not necessarily a precursor of SIDS.

Epidemiology

•SIDS is the leading cause of death in infants <1 year of age. Ninety percent of deaths occur before 6 months of age.

•The incidence is 0.54 per 1,000 live births in the United States.

•SIDS is more prevalent among African American infants.

•There has been a major reduction in SIDS since the launch of the Safe to Sleep (formerly Back to Sleep) Campaign in 1994.

•In spite of the reduction of SIDS, the incidence of SUID remains stable because of an increase in other causes of SUID (accidental sleep-related suffocation).

•The pathophysiology of SIDS is not completely understood. With the triple-risk hypothesis, a combination of 3 factors is postulated: a vulnerable infant (an abnormality in control of breathing), a critical developmental stage, and an outside stressor (sleeping in the prone position, parental smoking).

•The basis of a higher risk of SIDS when sleeping in the prone position may be secondary to upper-airway occlusion, rebreathing CO₂, or having an increased arousal threshold.

•Hyperthermia may produce peripheral vasodilation with a fatal drop in blood pressure.

•Autonomic nervous system dysregulation has been postulated because of sweating, hyperthermia, and tachycardia, followed by bradycardia preceding the death of the infant.