Frankie Roman M.D. J.D.Unity Health Network

Focus ConferenceMay 16, 2014

Sudden Infant Death Syndrome

SIDS - Definition• Sudden death of an infant ( < 12 months)

• Death unexplained after a thorough investigation

- review of history - complete autopsy - death scene examination

SIDS• Accounts for 0.6 deaths per 1000 live births in Western

countries

• Single most common cause of death in the post neonatal period (35%-55%)• 2/3 of SIDS death occur in infants aged 2-4 months

• 90% of deaths occur in children <8 months

• Few deaths occur in children < 1 month and > 8 months

Triple Risk Model

Critical Development Period• Unique age of occurrence: peak between 2-4 months

• Doubling of the brain weight

• Rapid changes that occur for functional integration of brain stem regions that subserve cardiorespiratory control

• Dramatic developmental changes in sleep state organization, arousal, cardiorespiratory control and metabolism

Vulnerable Infant• Abnormal homeostatic control during sleep• Altered ventilator drive• Altered autonomic control• Neurotransmitter and functional nerve cell

abnormalities• Arcuate nucleus deficiencies• Prematurity

Ex0genous Stressors• Infection• Child rearing practices – lower rates of pacifier use• Prone position of the baby• Over bundling and changes in ambient temperature• Tobacco smoke exposure

Prone Position• Higher risk for SIDS• Mechanisms - increased sleep duration - increased quiet sleep - fewer short arousals - rebreathing exhaled CO2 - upper airway obstruction - overheating due to decreased body heat dissipation

Apparent Life –Threatening Event ( ALTE)

• An episode that is frightening to the observer

• Characterized by some combination of apnea, color change, change in muscle tone, choking or gagging

Etiology Of ALTE

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Etiology of ALTE

Definable Cause Unknown

ALTE: Identifiable Causes29%

neurological gastrointestinal respiratory cardiac metabolic other

Recommended Evaluation for ALTE• Admission and observation with CR monitoring

• History, physical and neurological examination

• CBC , electrolytes, calcium, CXR, ECG, EEG

Evaluation of ALTE in selected cases• Sepsis work up• Barium swallow• Esophageal ph study• US/CT of Brain• Echocardiogram• Blood ammonia and urine amino acids• Polysomnogram

Indications for Home Cardiopulmonary Monitoring• 3 decades of monitor use did not prevent SIDS

• Significant ALTE for which no cause was found

• Twin of SIDS

• Multichannel documentation of clinically significant apnea

ALTEALTE

Begin Event Recording Monitor2-3 months with no true alarms

Event recorder normal

Discontinue Monitor

Congenital Central Hypoventilation Syndrome (CCHS)• Failure of autonomic control of breathing

• Rare disorder – 1 per 200,000 live births

• Disordered ventilation control may range in severity - hypoventilation during sleep with adequate ventilation during wakefulness - severe cases: hypoventilation during both sleep and wakefulness

CCHS• Minute ventilation is reduced during sleep due to reduction in

tidal volume with relatively well preserved breathing frequency.• Hypoventilation is worse during NREM sleep ( chemical control

of breathing).• Decreased or absent ventilator chemo sensitivity in response

to hypoxia and hypercapnia during wakefulness and sleep.• Thus children cannot generate signs of respiratory distress.• Hypercapnic arousal (exogenous) responses appear intact.• Abnormality is located in the area of brain stem responsible for

integration of chemoreceptor signals.

Clinical Features - Respiratory• Age – typically new born period, also child and

adulthood.

• Lack of perception of asphyxia during wakefulness with or without exertion

• Absence of primary lung, cardiac or neuromuscular disease or brain stem lesion.

Clinical Features – Non respiratory• Autonomic nervous system dysfunction - Anatomic Hirschsprung’s disease ( 20% of CCHS) Tumors of neural crest origin ( neuroblastoma) - Physiological symptoms Decreased pupillary response, esophageal dysmotility, breath holding spells, temperature instability, abnormal heart rate variability and cardiac asystoles

Disease Presentation and Clinical Course• Majority symptomatic during the newborn period.

• Fail to initiate respiratory effort requiring assisted ventilation from birth.

• Late onset beyond neonatal period – can present with episodes of severe apnea, apparent life-threatening event or problems in recovery from sedation and anesthesia.

Assisted Ventilation• Tracheostomy - Positive pressure ventilation via tracheostomy

• Noninvasive - nasal or face mask interface - bilevel positive pressure support in a spontaneous timed mode with back up rate

• Negative pressure ventilators• Diaphragmatic pacing

Positive Pressure Ventilation via Tracheostomy• Most common method used for children needing 24

hour ventilator y support.

• Ventilation can be accomplished via portable home ventilators in volume control/pressure control mode.

• Nocturnal hyperventilation with end tidal CO2 values in the 30-35 mg range can lead to improvement in day time ventilation.

Noninvasive Ventilation• Increasingly used, well tolerated even in younger

children.

• Effective mode of ventilation for children who need only night time support.

• Bilevel ventilation – difference in IPAP and EPAP generates adequate tidal volume

• Back up rate is dialed in to assure minute ventilation

Summary of CCHS• Hallmark of CCHS is absent ventilatory response to CO2 and

O2.• Exclusion diagnosis – need to rule out primary lung disease,

ventilatory muscle weakness, gross anatomic brain or brain stem lesions and inborn errors of metabolism.• Can present in later infancy, child and adulthood.• Majority of the affected patients require lifelong ventilatory

support.• 95% of cases identified by PHOX2• If negative, additional screening PHOX2B sequencing test

identifies subset of non- polyalanine repeat mutations (NPARM)