Difficulties at Birth: Long Term Developmental Outcomes

Transcription

1 Difficulties at Birth: Long Term Developmental Outcomes Alan D. Bedrick MD Division of Neonatology and Developmental Biology Department of Pediatrics University of Arizona Tucson, Arizona

2 DISCLOSURE I have no vested interest or intention to discuss off-label and/or investigational use of pharmaceuticals or devices I have no financial or other relationship with anymanufacturer or commercial product or servicesdiscussed in this presentation (other than the U of A which I love dearly)

3 OBJECTIVES Understand some aspects of labor and delivery which might result in perinatal brain injury Distinguish between those infants whose neurologic problems originated before birth vs. during birth Understand some of the long term neurologic outcomes of infants who sustained brain damage during birth Understand some of the medical-legal issues which result in referrals to vocational experts

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19 Case Report 3,060 gm full-term female infant born to 37 y.o. hospital administrator. Uncomplicated pregnancy. Mother presents with decreased fetal movement x 24 hours which resolved two days before delivery. Labor remarkable for failure to descend. Forceps assisted vaginal delivery. Apgar scores 4/8. Resuscitated with T- Piece resuscitator x few breaths. UA cord ph = 7.25.? Jittery at birth. D/C home after 48 hours. After 6 months, pediatrician notes failure to achieve normal major motor milestones and mild hypertonia, all extremities. Pediatrician reviews birth history. Comments to mother that maybe something happened at birth since forceps were used.

20 3,060 gm full-term female infant born to 37 y.o. hospital administrator. Uncomplicated pregnancy. Mother presents with decreased fetal movement x 24 hours which resolved two days before delivery. Labor remarkable for failure to descend. Forceps assisted vaginal delivery. Apgar scores 4/8. Resuscitated with T-Piece resuscitator x few breaths. UA cord ph = 7.25.? Jittery at birth. D/C home after 48 hours. After 6 months, pediatrician notes failure to achieve normal major motor milestones and mild hypertonia, all extremities. Pediatrician reviews birth history. Comments to mother that maybe something happened at birth since forceps were used years later, delivering obstetrician is sued for breach of the standard of care and failing to perform a timely Caesarean Section. Allegation is that had a Caesarean Section been performed, baby would not have cerebral palsy and would be normal. Vocational Rehabilitation Expert consulted re future capabilities, etc.

21 Definition: Cerebral Palsy Cerebral Palsy A general descriptive condition which is characterized by sustained, non-progressive neurologic disability characterized by abnormal control of movement and posture. The type (spastic diplegia/ quadriplegia; hemiplegia, etc.) is determined by the location of the lesion within the central nervous system, and the timing of its occurrence.

22 Definition: CognitiveImpairment Cognitive Impairment (MR) IQ score < 2 S.D. below the mean. The etiology of cognitive impairment generally occurs prenatally or during the early developmental years, and impairs the individual s ability to adapt to the environment. Average IQ = 100; MR IQ < 70 Etiologies: genetic, infectious, teratogenic, metabolic social factors (mild delay)

23 The Continuum of Influences Conception Labor and Delivery Infancy Childhood

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25 Perinatal Asphyxia is NOT a Diagnosis!! It is a physiological and biochemical state secondary to a known or unknown condition. Perinatal asphyxia may be due to specific clinical conditions which have pathophysiology evidenced by abnormal gas exchange (such as placenta previa, abruption, cord prolapse).

26 Rhesus Monkey Model Dawes (1964) Term Rhesus Monkeys Prior to delivery: - catheters placed in fetal vessels Delivery by Caesarean Section - head placed in saline filled rubber bag - umbilical cords immediately clamped Followed the course of selected physiological parameters during 10 minutes of total asphyxia followed by resuscitation

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29 Circulatory Changes During Asphyxia Redistribution of Cardiac Output (Selective Circulatory Ischemia) TO: FROM: Brain, Heart, Adrenal Glands Kidneys, Lungs, Mesentery, Muscle

30 PERINATAL ASPHYXIA AND CEREBRAL PALSY Is there a causal (or associative) relationship between antenatal/perinatal events and subsequent development of mental retardation or cerebral palsy? Are cerebral palsy and mental retardation preventable? Does perinatal asphyxia cause brain injury?

31 Causes of Cerebral Palsy Most ataxic/dyskinetic CP w/ MR is genetic in etiology Up to 50% of spastic CP in term infants is due to recognizable prenatal disorders cerebral dysgenesis / maldevelopment prenatal strokes [MCA] TORCH infections Other: Asphyxia : * Infection chorioamnionitis (FIRS) * Coagulation factors / auto-immune factor V Leiden; APA syndrome

32 Neuropathological Correlates Cerebral Palsy: damage to basal ganglia (extrapyramidal system) and surrounding white matter. Pathologically: scarring and cavitation in the basal ganglia with loss of periventricular tissue ---> hydrocephalus ex- vacuo [cystic periventricular leukomalacia] Cognitive Impairment: assoc. w/ cerebral cortical damage. Acutely: cortical cerebral edema and cell necrosis. Chronically: scarring and fibrosis Timing During Gestation: preterm, term Severity of Insult: chronic, acute

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35 Pathogenesis and Etiology of Perinatal Brain Damage Mechanisms of brain injury identified from pathologic studies can be corroborated in clinical studies. NIH Collaborative Perinatal Project, 1957 Cerebral palsy is not related to the events of delivery in term pregnancies, i.e. it does not occur as the result of complications during term delivery.

36 Temporal Spectrum of Perinatal Asphyxial Insults Infants may be born with subacute, old cerebral lesions The fetus subjected to ongoing adverse conditions during intra-uterine life may accrue subacute cerebral damage. If the fetus survives, acute lesions become subacute, heal, and scar. The presence of latent subacute lesions at birth may account for many cases of CNS dysfunction that develop after uncomplicated term delivery. e.g. Cellular Migration Disorders: lissencephaly, polymicrogyria

37 Acute vs. Chronic Injury: Clinical Patterns Depression of vital functions may occur in an infant with subacute brain damage which occurred long before the onset of labor. Acute vs. chronic damage may be clinically similar in first minutes of life; subsequent clinical pattern is different. Acute: coma, recurrent apnea, seizures, multi-system involvement Chronic: depressed; responds to resuscitation, goes to the regular nursery, and then home.

38 Neonatal Encephalopathy Clinically defined syndrome of disturbed neurologic function in an infant appearing early after delivery. Manifested by difficulty initiating and maintaining respiration; depression of tone and reflexes (hypotonia -> hypertonia) Profound alteration of consciousness, and often seizures Does not imply etiology [hypoxic ischemic encephalopathy] (vs metabolic, infectious) Perinatal Depression = Perinatal Asphyxia

39 Neonatal Encephalopathy: Etiology Hypoxia/Ischemia 40% Cerebro Vascular 11% Infection / Meningitis 11% Metabolic 10% Genetic 3% Unknown 25%

40 Is Perinatal Brain Injury Related to Obstetric Care?

41 Perinatal Events and Brain Damage YES THAT CAN HAPPEN!! Only for certain types of brain injury are perinatal asphyxial events possibly related to later outcome. Despite this: Techniques are not perfect for identifying the fetus at risk What severity and duration of acute or chronic asphyxia warrants aggressive obstetrical intervention?

42 Identification of At Risk Pregnancies Ante-partum Care - Risk Assessment: Biophysical profile - Serial U/S to document fetal growth Electronic Fetal Monitoring --> C - Sections If any of the screening tests are abnormal, one can suspect that a potentially compromised fetus may not withstand labor and may undergo a loss of capacity to tolerate labor. All our tools to assess fetal well-being during pregnancy and labor cannot prognosticate neurologic impairment

43 Perinatal Events and Outcome While some infants with evident perinatal asphyxia do poorly, most do well. Most newborn infants with objective clinical signs of perinatal asphyxia in the first days of life do well, and show no signs of permanent brain dysfunction (mild, moderate, severe encephalopathy) Whole Body Cooling for acute neonatal encephalopathy In the absence of specific clinical signs, perinatal asphyxia can seldom be ascribed as the cause of brain damage.

44 Perinatal Events and Outcome If the incidence of CP was related to suboptimal obstetrical care (failure to perform timely C-S), then its prevalence should be decreasing. IT HAS NOT DONE SO! (Incr. CS -> No decr. CP!) The rate of cerebral palsy parallels substantial increases in survival in very low birth weight infants. The rate of CP is many times higher among infants < 1500 g at birth versus full-term infants.

45 When is Severe Fetal Asphyxia Followed by Brain Damage? Usually see: severe metabolic acidosis multi-system derangement - CV, GI, Renal stormy newborn neurologic course - A fetus compromised by an earlier prenatal event is more likely to exhibit evidence of asphyxia than a normal fetus. - Fetal distress may be followed by brain damage, but the obstetrician may be unable to interrupt that relationship. Spastic quadriplegia is the most prevalent type of cerebral palsy in term infants

46 Can Asphyxia ---> Brain Injury? Best Evidence Identifiable sequence of events Identified cause of fetal oxygen interruption Early neonatal signs w/ subsequent encephalopathy Consistent neuroimaging studies: early: edema; no prenatal lesions later: atrophy / destruction [global; diffuse] Static motor disorder: spastic quadriplegia w/ dyskinesia

47 What Suggests a Cause of Cerebral Palsy OTHER than Acute Perinatal Asphyxia? Intrauterine growth retardation Umbilical cord ph > 7.0; base deficit < 12 mmol/l Systemic infection Neuroimaging: long-standing abnormalities Decreased FHR variability at onset of monitoring Microcephaly Extensive chorioamnionitis Congenital coagulopathy Other risk factors: prematurity; multiple births

48 Relationships between time course of asphyxial insult, site(s) of brain injury, and type of disability TIME COURSE SITE OF BRAIN INJURY DISABILITY Acute Near Total Moderate Basal Ganglia/Thalami Athetoic/Dystonic CP Impaired Cognitive Development Severe BG/T + Cerebral Cortex Severe spastic QP, cortical, visual impairment, cognitive, microcephaly Prolonged Moderate Watershed Regions Moderate Spastic QP, cognitive deficit cognitive impairment, Severe Extensive Cortical Pathology Spastic QP, severe impairment, visual microcephaly

49 Follow Up and Intervention Detectability of Impairment 1 st year: Severe Motor / Sensory Loss 2 nd year: Low Developmental Quotient 2-4 years: Fine/Gross MotorDysfunction 4-7 years: Cognitive Abnormalities 7-9 years: Learning Disbalities

50 Follow Up and Intervention Intensive Follow Up for Those at High Risk for Disability Vision Loss: pediatric ophthalmology Hearing Loss: brain stem evoked response, audiologist Seizures: pediatric neurology Nutrition: nutritionist; gastrostomy tube

51 Follow Up and Intervention 4 8 Month Neurodevelopmental Follow Up Feeding/Nutrition Head Growth Visual Awareness Oral Motor Function (salivary control Early Vocalization Physical Therapy Assessment

52 Follow Up and Intervention Month Neurodevelopmental Follow-Up Pediatric Rehabilitation Ongoing Multidisciplinary Follow Up Speech Pathology Physical Therapy Occupation Therapy Bayley III Testing

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55 Physicians and nurses need to accept the notion that error is an inevitable accompaniment of the human condition, even among conscientious professionals with high standards. Errors must be accepted as evidence of system flaws not character flaws.

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58 Reasons Why People Sue Their Doctors Percent Expressing Concern Advised to sue by influential other 32 Needed money 24 Believed there was a cover-up 24 Child would have no future 23 Needed information 20 Wanted revenge, license 19 Source - Hickson, 1992

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66 ? Perinatal Events -> CP 1. Despite advances in perinatal care, the societal burden of cerebral palsy has not decreased. Advanced NICU technology has permitted survival of tinier, more premature infants resulting in more children with CP 2. Cerebral palsy in children born at term often reflects phenomena which preceded the onset of labor. 3. Most cerebral palsy is not preceded by severe intrapartum asphyxia.

67 ? PerinatalEvents -> CP 4. Most severely asphyxiated infants who survive are later clinically normal, and DO NOT develop cerebral palsy or mental retardation. 5. The diagnosis of fetal asphyxia is imprecise. 6. Fetal asphyxia may follow fetal brain damage. 7. Efforts to prevent evident perinatal brain injury will require a focus on factors and events during pregnancy, especially those which result in preterm delivery.

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