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Newborn screening. Dr.Reeta Bora MD,DM(Neonatology) Astt. Professor of Neonatology Dept of Pediatrics Assam Medical College, Dibrugarh. Greetings from Assam Medical College, Dibrugarh. Introduction.
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Newborn screening Dr.Reeta Bora MD,DM(Neonatology) Astt. Professor of Neonatology Dept of Pediatrics Assam Medical College, Dibrugarh
Introduction • Screening: A brief assessment procedure designed to identify those who should receive more intensive diagnosis or assessment • An attractive approach to preventive medicine • Screening makes sense if– condition reasonably common, serious consequences occur if not intervened early, availability of early & effective intervention • If not used judiciously may damage health, resources • Considering present neonatal health status of Assam, high risk approach for neonatal screening rather than universal screening is perhaps a better approach.
Topics to be discussed • Screening at risk newborn for • Neuro developmental disability • ROP & Visual distubances • Hearing • Screening for Inborn error of metabolism
Neurodevelopmental screening • Aims at identifying those who need more comprehensive evaluation • Why routine screening? • Whom to screen? • Who are high risk Newborn? • Who should screen • What should be the property of screening tests • Screening tests • Follow up
Why routine screening? Early & accurate detection of developmental problem is necessary as- • limited window of malleability of the developing brain-needs early identification and intervention • Early intervention leads to better social, adaptive & intellectual activity
Whom to screen? • Ideally all infants time consuming, needs large no of trained person, not cost effective. • High risk infants
Who are high risk Newborn? • Preterm <33 wk GA • BW<1500 gm • IVH/PVL • Asphyxia/Neurological problems • Persistent/recurrant hypoglycemia • Ventilated • Jaundice needing DVET • Complex medical course • Sepsis/meningitis • Multiple CMF/Genetic disorder
Who should screen? Pediatrician • Skilled in use of screening techniques • Actively seek parental concern about development • Creates links with available resources in the community Multi disciplinary management needed • Neurological assessment • Developmental-intellectual assessment • Language • Hearing assessment • Visual assessment
Properties of a screening test Best insrtument has • Adequate sensitivity • Adequate specificity • Adequate validity and reliability • Standardized on various population • Simple brief, convenient to use, cover all areas of development • Culturally sensitive
Neurological assessment Commonly used method: • Amiel Tison’s: • Based on evaluation of active tone & passive tone • Done at 6wks,3m,6m,9m,12m of age. • Identifies tone anomalies for early intervention • Disadvantage: doesn’t assess mental development
Neorodevelopment assessment Assessment of passive tone
Neurobehaviour assessment in newborn period • Brazelton’s neurobehavioral assessment scale Asses NB behavior on 28 items, scored on 9 point scale Elicits evidences of cortical control & responsiveness. • Neonatal Intensive care unit network neurobehavioral scale(NNNS) includes • Classical neurological items • Behavioral items • Stress/abstinence items
Developmental screening test after newborn period • DDST Has 125well standardized easily administered test item Age range: 0-6 yrs sensitivity:0.13 -0.46 • TDSC Acceptable simple tool Does not need developmental kit Age range0-2yrs sensitivity 0.67, specificity0.79 • Baroda developmental screening test Has 22 motor & 32 mental items Easy to use Gives developmental qotient
Screening for ROP and Visual problems • PREVELANCE BW <1250g 65% <1000g 80% • WHOM : < or = 32wk <1700gm prolonged oxy admn • WHEN : 4-6 wk postnatal age <28wk gestation at 32wk PCA
International Classification of ROP • Four components • Location:progression of developing vessels, Zone 1,2,3 • Stage I to V • Plus disease :Tortuisity & dilataion of vessels • Extent : Compartments involved
Different stages of ROP Stage I: Line of demarcation Stage II : Ridge Stage III :Ridge with extraretinal fibrovascular proliferation Stage V : complete retinal detachment Stage IV : Partial retinal detachment
ROP Screen -cont • If no ROP but retinal vascularization is incomplete re screen every 2 weeks till complete. • Mild ROP: Screen wkly • Monitor all treated till preschool years.
Hearing screen • Robinette and White cite a number of prevalence studies of newborn hearing loss which report ranges from 1 per 1000 live births to 6 per 1000 live births. • Crucial speech and language development begins during the first six months after birth and is crucial to development of communication. Therefore, "early detection and intervention are critical
Screening for hearing • 1896:Use of bell, whistle without child seeing source(Dr.Thomas Barr) • 1940:Same method remained in practice • 1960-70:Autonomic conditionable response • 1984: Crib o gram • 1990: BERA & OAE
BERA • Potentials recorded from ear and vertex in response to brief auditory stimulation to assess the conduction through auditory pathway upto the midbrain.
Normal Bera Waveform generators I VIII Nerve II Cochlear nucleus III Superior olivary N IV Lateral leminiscus V Inferior coliculi
Normal BERA • Classic baep consists of 5-8 vertex positive peaks. • Initial 5 are of clinical interest. • Obligate BAEP waves are 1,3and 5. • 2,4,6,7 can be absent in some normal subjects, but absence of any obligate wave is abnormal.[most common wave to be absent is wave1].
Abnormal BERA • Obligate wave absence. • Abnormal absolute or interpeak latencies. • Amplitude ratio abnormality. • Significant right to left assymetry[>0.5 ms difference is significant].
RECORDING ELECTRODES Screening at 3-6 months more accurate as it excludes abnormalities due to perinatal conductive deafness Of neonates coming out of nicu 1-5 %will have sensorineural hearing loss[stockhord etal 1986].
Clinical Use INDICATIONS; • Family history of hearing impairment • Downs syndrome • Prematurity with risk factors such as injuries, meningitis, kernicterus, asphyxia. • Encephelitis, hydrocephalus, • Children receiving ototoxic drugs • Children with intellectual impairment • Children with chronic middle ear disease • Screening of neonates coming out of nicu.
NEONATAL NEUROLOGICAL DISEASE AND PROBABLE REGION OF INVOLVEMENT
Otoacoustic emissions • Sounds which arise in the ear canal when (paradoxically) the TM receives vibrations transmitted backwards through the middle ear from the cochlea • First measurement reported in 1978 by David Kemp from the Institute for Laryngology and Otology
Sensitivity Specificity Auditory Brainstem Response (ABR) 97%-100% 86%-96% Evoked Otoacoustic Emissions (EOAE) 84% 92% OAE vs BERA • More easy to perform • Rapid 2-10 min vs 1.5 hr for ABR • Less expensive Sensitivity and Specificity of Two Main Forms of Newborn Hearing Testing (HEALTH TECHNOLOGY ADVISORY COMMITTEE)
Flow chart for infant with hearing loss Failed screen(BERA,OAE) Repeat after 1 m Diminished hearing Diminished hearing Normal hearing Mod sev to profound deafness Mild/moderate deafness h.Aid speech therapy H aid/speech therapy H aid/speech therapy Rpt test 3monthly-exclude progessive hearing loss Aided audiometry &h.aid Inadequate help Adequate help-contn rehab Cochlear implant
Screening for Inborn Error of metabolism,endocrinopathies • IEM –Inherited disorders due metabolic block because of deficiency of enzyme. • Not uncommon –needs consideration in d/d of sick NB • Early detection has potential for Ry & prevention of death • Incidence :1/5000 live
Indian studies SGRH, Delhi total 393 cases screened 6.7% had IEM Radha Ram et al,IJP,Feb2004 Cong hypothyroidism-1:1700 CAH -1:2575 phenylketonuria:-1:18300 I
Approach to IEM • Universal • At risk- • History of acute deterioration after a period of normalcy • Family h/o consanguinity • Progressive illness- cerebral signs • Unusual odor
What happens? A--------B-----/----C Metabolic pathway D----------E Absence of product C Accumulation of alternate product D or clinical features Accumulation of substrates A Or intermediates B E.g.: • Accumulation of substrates : storage disorders,Urea cycle defectsOrganic aciduria • Accumulation of intermediate metabolite: Galactosemia Fructosemia Tyrosenemia • Absence of products :Mitochondrial oxidation defects,Fatty acid oxidation defects
Suspicion • Clinical • Acute illness following a period of normalcy • Lethargy or coma • Hypotonia, seizures (difficult to control), intractable hiccups • Respiratory distress • Sepsis or sepsis like illness with no predisposition, E.coli sepsis • Vomiting • Cholestatic jaundice • Unusual odor • Dysmorphic features • Organomegaly: hepatomegaly, renomegaly • Positive family history-----autosomal recessive and X linked • Unexplained early neonatal deaths • Parental consanguinity
hypoglycemia Rule out sepsis,SGA,IDM,Syst illness Non gluc reducing. Subs in urine positive negative galactosemia,HFI Plasma ammonia Urinary ketone low high Plasma FFA hepatomegaly Low-hyperinsulinemia Consider:FAOD absent present Plasma.lactate Plasma hGH,cortisol,T4 Normal-ketotic hyperglycenemia high:GSD1 Abnormal-endocrinopathy
Collection storage & Transport of sample • Urine • Routine biochemical test, protein, glucose,reducing subs, pH • Chemical test like DNPH, ferric chloride • Aminoacid chromatography • Organic acid • Blood • Ammonia-Sample in heparinized vial needs transpotation to lab on ice immediately. • Lactate-fluoride vial • Galactosemia & tyrosenemia- heparinised • For TMS- Fresh blood in filter paper
Wilson & Jugner Criteria for screening(WHO1968) • Condition must be an important public health problem • Clinically & biochemically well defined • Disorder associated with significant mortality & morbidity • Effective treatment available • Period before onset during which intervention improves outcome • Ethical safe simple & robust screening test • Cost effectiveness of screening test established.
Conclusion • Technological advance has made possible survival of more sicker & smaller babies. To have intact survival screening & intervention of these high risk babies is very important. • Routine screening for IEM/endocrinopathies before discharge is desirable but not justifiable at the present scenario of newborn health in Assam, but availability of screening tests can be utilized when clinical suspicion is there. • Pilot studies are required to know the prevalence of disease before universal screening programmes.