Apparent Life-Threatening Events (ALTE)

Def. Apparent Life-Threatening Event (ALTE)* – “An episode that is frightening to the observer, that is characterized by some combination of apnea (centrally or occasionally obstructive), color change (usually cyanotic or pallid, but occasionally erythematous or plethoric), marked change in muscle tone (usually marked limpness), choking or gagging”.  This journal club will review some articles on Apparent Life-Threatening Events.
*As established at the 1986 National Institute of Health Consensus Development conference on Infantile Apnea and Home Monitoring

After evaluating this article participants will be able to:
1. Define the characteristics of an apparent life threatening event (ALTE)
2. Recognize the utility of diagnostic testing in patients who have experienced an ALTE
3. Be aware of the incidence of serious bacterial infections in ALTE patients

 

Def. Apparent Life-Threatening Event (ALTE)* – “An episode that is frightening to the observer, that is characterized by some combination of apnea (centrally or occasionally obstructive), color change (usually cyanotic or pallid, but occasionally erythematous or plethoric), marked change in muscle tone (usually marked limpness), choking or gagging”.  This journal club will review some articles on Apparent Life-Threatening Events.

Study #1: Stratton SJ, Taves A, Lewis RJ et al.

Apparent life-threatening events in infants: high risk in the out-of-hospital environment. Ann Emerg Med. 2004 Jun;43(6):711-7

Purpose: To define the prevalence and significance of apparent life-threatening events among infants in the out-of-hospital setting.

 

Methodology: This was a retrospective, cohort, outcome study of infants for whom a caregiver activated the emergency medical services (EMS) system. For purposes of the study, an apparent life-threatening event was defined as an episode of apnea, skin color change, or change in muscle tone. Study data characteristics included initial physical appearance, work of breathing, circulation skin signs, pulse rate, respiratory rate, and overall concern for the chief complaint as interpreted by EMS personnel.

 

Results: Sixty (7.5%) of 804 infants encountered by EMS during the study period met our criteria for apparent life-threatening event. Mean age was 3.1+/-3.3 months, and 55% were boys. Of the infants with apparent life-threatening event, 50 (83.3%) infants appeared to be in no distress, 8 (13.3%) infants were in mild distress, and 2 (3.3%) infants were in moderate distress. General physical appearance, work of breathing, circulatory signs, respiratory rate, and pulse rate were not clinically abnormal in the study group as a whole. Critical conditions associated with apparent life-threatening event included pneumonia or bronchiolitis (12%), seizure (8%), sepsis (7%), intracranial hemorrhage (3%), bacterial meningitis (2%), dehydration (2%), and severe anemia (2%). Limitations of the study included retrospective design and inability to follow up study patients beyond hospital discharge.

 

Conclusions:  An apparent life-threatening event in an infant can present without signs of acute illness and is commonly encountered in the EMS setting. It is often associated with significant medical conditions, and EMS personnel should be aware of the clinical importance of an apparent life-threatening event. Infants meeting criteria for an apparent life-threatening event should receive a timely and thorough medical evaluation.

Study #2: Claudius I, Keens T. Do all infants with apparent life-threatening events need to be admitted? Pediatrics. 2007 Apr;119(4):679-83

Purpose: To identify criteria that would allow low-risk infants presenting with an apparent life-threatening event to be discharged safely from the emergency department.

 

Methodology: We completed data forms prospectively on all previously healthy patients <12 months of age presenting to the emergency department of an urban tertiary care children’s hospital with an apparent life-threatening event over a 3-year period. These patients were then observed for subsequent events, significant interventions, or final diagnoses that would have mandated their admission (eg, sepsis).

 

Results:  In our population of 59 infants, all 8 children who met the aforementioned outcome measures, thus requiring admission, either had experienced multiple apparent life-threatening events before presentation or were in their first month of life. In our study group, the high-risk criteria of age of <1 month [corrected]and multiple apparent life-threatening events yielded a negative predictive value of 100% to identify the need for hospital admission.

 

Conclusions: Our study suggests that >30-day-old infants who have experienced a single apparent life-threatening event may be discharged safely from the hospital, which would decrease admissions by 38%.

 

Study #3: Brand DA, Altman RL, Purtill K, Edwards KS. Yield of diagnostic testing in infants who have had an apparent life-threatening event. Pediatrics. 2005 Apr;115(4):885-93.

 

Purpose: To determine the yield of different diagnostic tests in helping to identify the cause of the ALTE.

 

Methodology: Test results were reviewed from a consecutive series of infants who were younger than 12 months and admitted to a tertiary care academic medical center between November 1996 and June 1999 after having experienced a sudden breathing irregularity, color change, or alteration in mental status or muscle tone.

 

Results: A total of 243 patients met the enrollment criteria. Of the 3776 tests ordered, 669 (17.7%) were positive and 224 (5.9%) contributed to the diagnosis. Prompted by findings from the initial clinical assessment, the following tests proved useful in patients who had a contributory history and physical examination: blood counts, chemistries, and cultures; cerebrospinal fluid analysis and cultures; metabolic screening; screening for respiratory pathogens; screening for gastroesophageal reflux; chest radiograph; brain neuroimaging; skeletal survey; electroencephalogram; echocardiogram; and pneumogram. In the remaining patients, who had a noncontributory history and physical examination, only the following tests proved useful: screening for gastroesophageal reflux, urine analysis and culture, brain neuroimaging, chest radiograph, pneumogram, and white blood cell count. Broad evaluations for systemic infections, metabolic diseases, and blood chemistry abnormalities were not productive in these patients.

 

Conclusions: For many tests used in the evaluation of an ALTE, the likelihood of a positive result is low and the likelihood of a contributory result is even lower.

Study #4: Zuckerbraun NS, Zomorrodi A, Pitetti RD. Occurrence of serious bacterial infection in infants aged 60 days or younger with an apparent life-threatening event. Pediatric Emergency Care 25:19-25, 2009.

Summary: This study retrospectively reviewed microbiologic testing in a cohort of well-appearing, afebrile infants aged 60 days or younger who presented with an ALTE to a children’s hospital emergency department between January 2002 and July 2005.

 

Methodology: All patients were admitted and followed up for 6 months. Comparisons were made among those who did and did not undergo microbiologic testing and full sepsis evaluation (blood, urine, and cerebrospinal fluid) and those who did and did not have an SBI.

 

Results: Of 182 patients, 112 (61.5%) underwent microbiologic testing, and 53 (29.1%) had a full sepsis evaluation. Five patients (2.7%; 95% confidence interval, 0.9%-6.3%) had an SBI including 3 positive results in blood cultures, 1 positive result in urine culture, and 1 positive result for pertussis by polymerase chain reaction. No patient had a positive result in cerebrospinal fluid culture (95% confidence interval, 0%-5.7%). Patients with a history of prematurity were more likely to have an SBI (6.7% vs. 0.8%, P = 0.04).

 

Conclusions: Serious bacterial infection occurred in 2.7% of well-appearing, afebrile infants aged 60 days or younger with an ALTE. Prematurity was associated with having an SBI. For premature infants aged 60 days or younger who present with an ALTE, an evaluation for SBI should be strongly considered.

 

Patients who suffer from apparent life-threatening events and are brought in by paramedics should not be overlooked as many have treatable underlying diagnoses. While the Claudius study decreases the hospital admission rate significantly, the small number of patients evaluated would make it difficult to change our current practice of admitting all children with ALTE’s, particularly in our medicolegal climate. The evaluation of an ALTE is not based on a “shotgun” approach, but by close attention the history and physical examination. However, there should be a high index of suspicion for serious bacterial illness in premature infants and infants less than 60 days of age