(proximal) II RTA: impaired reabsorption of bicarbonate from 05_McClure_05.indd 104 11/15/2012 12:19:03 AM OTHER ACID \200\223BASE PROBLEMS 105 Clinical assessment History A thorough history is important. You will need to identify any symptoms of fever, \202 ank pain, and vomiting (pyelonephritis), lethargy, or altered men tal state (metabolic disease or poisoning). Then ask speci \201 c questions about the gast rointestinal and renal tracts, and growth. Last there may be a signi \201 cant family hist ory of renal disease, kidney stones, or early infant death. Examination A full examination is needed. Assess: \200 \200 \200 \200 \200 Hydration. Growth. Respiratory state (compensation for metabolic acidosis). Abdomen. CNS. Investigations Until you know the diagnosis, the key tests are as follows. \200 FBC with differential, serum electrolytes with urea and Blood. creatinine, glucose, LFTs (t ransaminases), arterial or capillary blood gas, lactate, pyruvate, ketone, plasma amino aci ds, ammonia, carnitine, and drug screen. Urine: and drug screen. Imaging: urinalysis, ketones, reducing substances, organic and amino acids, renal US scan looking for nephrocalcinosis (type I RTA). Monitoring Ensure the ABCs. Then, the form and type of monitoring will be dictated by the p atient \200\231s condition. Start with continuous pulse oximetry and ECG monitoring, and in termittent BP monitoring. Follow hourly output. Therapy If the patient is dehydrated then this problem should be treated with oral or IV re placement. This alone may improve serum bicarbonate. However, for the speci \201 c metabol ic disorders: \200 \200 Increased Distal pp.382 \200\223385); RTA: correct serum bicarbonate and increase \202 ui ds Hyperkalaemic to improve sodium delivery to the distal tubule (this will enhance potassi um secretion). AG: identify cause and treat; or proximal RTA: bicarbonate supplementation (see also b Bicarbonate treatment If you are using bicarbonate then: \200 \200 3]) x weight (kg) x 0.5mmol; Estimate the de \201 cit = (20 \200\223 [HCO Replace over 24 \200\22348hr with oral suppl ements. 05_McClure_05.indd 105 11/15/2012 12:19:03 AM CHAPTER 5 Emergency and high dependency care 106 Further reading BSPED-recommended DKA Management Guidelines (2009). Available at: M www.bsp ed.org.uk/ professional/guidelines/docs/DKAGuideline.pdf Wolfsdorf J, Craig ME, Daneman D, et al. (2007) ISPAD Clinical Practice Consensus Guideline s 2006 \200\2232007. Pediat Diabet 8: 28 \200\22343. For the evidence base to the DKA manag ement guidelines, see the 2007 ISPAD guidelines. Available at: M http://www.ispad.org/FileC enter/10-Wolfsdorf_ Ped_Diab_2007,8.28 \200\22343.pdf 05_McClure_05.indd 106 11/15/2012 12:19:03 AM 107 Chapter 6 Neonatology Newborn life support 108 Perinatal de \201 nitions 110 Small for gestational age 111 Large for gestational Conventional positive pressure ventilation 162 High frequency oscillatory ventilation 164 Bronchopulmonary dysplasia 166 age 112 Prematurity 114 Birth at the limit of viability 116 Outcome following prematurity 117 Basic obstetrics 118 Obstetric problems 120 Maternal disorders causing neonatal disease 124 Circulatory adaptation at birth 168 Patent ductus arteriosus 169 CNS malformations 170 Hypoxic \200\223ischaemic encephalopathy 172 Cerebral hemorrhage and ischaemia 176 Birth trauma 126 Non-speci \201 cally ill neonate 128 Necrotizing enterocolitis 178 Neonatal infection 180 Transplacental (congenital Neonatal jaundice 130 Hypoglycaemia 132 Neonatal seizures 134 The \202 oppy infant 136 Hy drops foetalis 138 Routine care of the newborn 140 Milk feeding 142 Routine neonatal infection) 182 Prevention of neonatal infection 184 Neonatal abstinence syndrome 186 Inborn errors of metabolism 187 Retinopathy of prematurity 188 examination 144 Metabolic bone disease 190 Orofacial clefts 191 Neonatal hematology 192 Rh disease (rhesus haemolytic Normal variations and minor abnormalities 146 Newborn \202 uid and electrolyte balance 148 disease) 194 Respiratory distress syndrome 150 Acute respiratory diseases 152 Bilirubin encephalopathy (kernicterus) 195 Neonatal dermatology 196 Perinatal death 198 Neonatal X-rays 156 Neonatal respiratory support 160 06_McClure_06.indd 107 11/14/2012 11:22:39 PM CHAPTER 6 Neonatology 108 Newborn life support All who attend deliveries should be pro \201 cient in newborn resusci tation, ideally taught on a recognized course (newborn life support (NLS) or equivalent). T he algorithm on b p.109 demonstrates a general approach to resuscitation (see Fig. 6.1). Pr eterm infants require special consideration (b p.114). Before birth \200 \200 Check equipment. Ask about: Gestation? Fetal distress? Meconium? At birth \200 For uncompromised babies, a delay in cord clamping of at least one minute is recommended. T here is insuf \201 cient evidence to recommend a delay in babies who require resuscitation . Meconium \200 Vigorous infants born through meconium stained liquor do NOT require airway suctioning eith er on the perineum or the resuscitaire. Pale, \202 oppy, poor respiration, or bradycardia ? Inspect oropharynx and perform suction if required. If appropriate expertise is available , tracheal intubation and suction may be useful in non-vigorous babies. If expertise not av ailable, or if attempted intubation is prolonged or unsuccessful, start mask ventilation, p articularly if there is persistent bradycardia. Lung in \202 ation \200 \200 \200 In \202 ation breaths are given initially, use air (21% O 3s each breath, 7 30cmH Once the chest is moving, ventilation breaths (shorter and gentler) are given at a rate of 30 \200 \22340/min if required. 2). 20 (term infants) \200\224give in sets of 5. Airway maneuvers \200 \200 \200 \200 Jaw thrust (2 person technique very useful). Direct inspection of oropharynx and airway suc tion. Guedel airway. Intubation (if competent). Chest compressions \200 \200 \200 7100/min, using two thumbs technique. Rate 3 chest compressions per lung in \202 ation (3: 1 ratio). Re-assess infant after each 30secs (15 cycles). Drugs \200 Give through umbilical venous catheter (UVC) or IO (high dose endotracheal tube (ETT) adren aline can be considered). Remember, drugs are B.A.D. ( Bicarbonate/Adrenaline/Dextrose 10%). 06_McClure_06.indd 108 11/14/2012 11:22:39 PM NEWBORN LIFE SUPPORT 109 Dry the baby Remove any wet towels and cover Start the clock or note the time Birth AT 30 s Assess (tone), breathing and heart rate ALL If gasping or not breathing: Open the airway Give 5 inflation breaths Consider SpO2 monitor ing STAGES 60 s Re-assess If no increase in heart rate look for chest movement ASK: Acceptable* pre-ductal SpO2 2 min 60% 70% 3 min 80% 4 min 85% 5 min 90% 10 min If chest not moving: Recheck head position Consider 2-person airway control and other airwa y maneuvers Repeat inflation breaths consider SpO2 monitoring Look for a response If no increase in heart rate look for chest movement DO When the chest is moving: If heart rate is not detectable or slow (<60/min) Start chest com pressions 3 compressions to each breath YOU NEED Reassess heart rate every 30s If heart rate is not detectable or slow (<60/min) consider ve nous access and drugs HELP? Fig. 6.1 Newborn life support. SpO2 values are 25th centile for term infants. Reproduced wi th kind permission of Resuscitation Council (UK) 2010. 06_McClure_06.indd 109 11/14/2012 11:22:39 PM CHAPTER 6 Neonatology 110 Perinatal de \201 nitions See also b p.10. Gestational age (post-menstrual age) Age measur ed from the \201 rst day of the last menstrual period before conception and expressed in com- plete weeks or days. Chronological/postnatal age Time elapsed from birth. Corrected age Chronological age minus the number of weeks born before 40wks gestation. Spon taneous abortion (miscarriage) A conceptus born after spontaneous labor without any signs o f life before 24 completed weeks gestation. Live birth A baby that displays any sign of lif e (i.e. breathing, heart beat, cord pulsation, or voluntary movement) after complete delive ry from the mother, irrespective of gestation. Stillbirth (late fetal death) Fetal death pr ior to complete delivery from the mother after 24 completed weeks gestation. Perinatal mort ality Includes all stillbirths and neonatal deaths in the \201 rst week. UK rate 77 \200 \2238 per thousand total births. Neonatal mortality Death amongst live births before 28 day s of age (whatever the gestation at birth). UK rate 73 per thousand live births. Neonatal p eriod From birth to 28 postnatal days in term infants. If preterm, from birth to 44wks post -menstrual age. Preterm Birth before 37 completed weeks gestation. 78% of births. Term birt h Between 37 and 42 completed weeks gestation. Post-term (post-mature) Birth after 42 compl eted weeks gestation. <5% of births. Low birth weight (LBW) Birth weight <2500g. 7% of birt hs. Very low birth weight (VLBW) Birth weight <1500g. 1.2% of births. Extremely low birth w eight (ELBW) Birth weight <1000g. Small for gestational age (SGA) Birth weight <10th centil e for ges- tational age. Large for gestational age (LGA) Birth weight >90th centile for ges - tational age. 06_McClure_06.indd 110 11/14/2012 11:22:39 PM SMALL FOR GESTATIONAL AGE 111 Small for gestational age SGA is birth weight <10th centile for gestational age. Intrauteri ne growth restriction (IUGR) is failure of growth in-utero that may or may not result in SG A. \200 Symmetric (proportional) SGA: small; suggests fetus affected from early pregnancy, e.g. chr omosomal disorder or constitutional. Asymmetric (disproportional) SGA: circumference. Usual ly because of IUGR due to insult in late pregnancy, e.g. pre-eclampsia. Asymmetric SGA infa nts at risk of complications. all growth parameters symmetrically weight centile < length and head Causes \200 \200 Constitutional, i.e. small parents (commonest). Restricted fetal O maternal hypertension, m ultiple pregnancy, maternal illness. Fetal abnormality, e.g. chromosomal disorders, congeni tal anomalies and syndromes, congenital infection. Maternal substance exposure, e.g. alcoho l, smoking, therapeutic or other drugs. 2 or glucose supply, e.g. placental dysfunction, Complications i \200 \200 Risk of fetal death and asphyxia (SGA indicates fetal compromise). May have congenital infection, toxoplasmosis, others, rubella, cytomegalovirus, herpes viru s II (TORCH) or malformation (b p.182). Hypoglycaemia (due to decreased glycogen stores; Hy pothermia. b p.192). Polycythaemia (secondary to chronic intrauterine hypoxia; Necrotizing enterocolitis and/or intolerance of feeds (chronic fetal bowel hypoxia; b p.178). Thrombocy topenia/neutropenia/coagulopathy (bone marrow/hepatic compromise; b p.193). Meconium aspira tion syndrome ( \200 \200 \200 b p.187). s to fetal hypoxia; b p.152). Management Ideally manage on a postnatal ward with increased ratio of midwives. \200 \200 \200 \200 \200 \200 Routine postnatal care. Evaluate clinically for features suggestive of underlying cause. Pa rticular attention to thermal care and blood glucose monitoring. Observe temperature, pulse , and respiration for at least the \201 rst 48hr. Admit to neonatal unit if birth weight <1800g. Well infants can be discharged when: they are sucking all feeds 3 \200\2234-hourly; weight gain is satisfactory (20 \200\22330g/day); body temperature is maintained at room t emperature; mother is capable of caring for infant. Prognosis See also b p.117. Neurodevelopmental impairments more common in SGA infants. Symm etric SGA infants often stay small. The Barker hypothe- sis suggests IUGR infants with a sm all placenta are at risk in later life of coronary disease, stroke, obesity, and hypertensi on. 06_McClure_06.indd 111 11/14/2012 11:22:39 PM CHAPTER 6 Neonatology 112 Large for gestational age De \201 ned as birth weight >90th centile for gestational age. Causes \200 \200 \200 \200 \200 Most frequently constitutional, i.e. large parents. Infant of a mother with diabetes mellit us. Fetal hyperinsulinism, pancreatic islet cell hyperplasia. Hydrops foetalis ( Beckwith \200\223Wiedemann syndrome (BWS; b p.138). b p.949). Complications \200 \200 \200 Perinatal asphyxia, nerve palsies, shoulder dystocia, fractures. Hypoglycaemia, especially if due to maternal diabetes or in BWS. Problems associated with the underlying cause LGA. Management \200 \200 \200 Careful obstetric management to prevent obstetric complications. Examine for associated fea tures, e.g. BWS or signs of birth injury. Prevent hypoglycaemia ( b p.132). Prognosis Generally excellent (unless hydrops foetalis) if managed well. Infant of a mother with diabetes mellitus Pathophysiology Maternal hyperglycaemia l i fetal glucose l i fetal insulin secretion (antenatally has growth hormone function) l macrosomia , organomega- ly, and polycythaemia. Rarely, maternal vascular disease results in fetal IUG R. Associated complications \200 x risk of congenital abnormalities: caudal regression syndrome 2 \200\2234 (sacral and femo ral agenesis or hypoplasia); transient hypertrophic cardiomyopathy; small left colon syndro me; neural tube defects. complications (see b Complications): increased risk of Obstetric s pontaneous miscarriage, intrauterine fetal death, and prematurity. Hypoglycaemia Respirator y Polycythaemia Exaggerated physiological jaundice. Hypocalcaemia and hypomagnesaemia. \200 \200 \200 \200 : generally resolves as serum insulin level falls. disease: respiratory distress. . Risk of secondary thrombosis (e.g. renal vein). Management Optimize maternal glycaemic control during pregnancy (d risk of compli- cations except for congenital abnormalities; see b p.120). Prognosis \200 \200 x increased risk of diabetes mellitus in later life. \200 Normoglycaemia occurs within 48hr in vast majority. 7 Increased risk of later obesity and, possibly, poor development. 06_McClure_06.indd 112 11/14/2012 11:22:40 PM LARGE FOR GESTATIONAL AGE 113 06_McClure_06.indd 113 11/14/2012 11:22:40 PM CHAPTER 6 Neonatology 114 Prematurity Birth before 37 completed weeks gestation. 8% of all births. Most prob- lems se en in with infants born <32 completed weeks (72% of all births). Predisposing factors \200 \200 \200 \200 Idiopathic (40%). Previous preterm birth. Multiple pregnancy. Maternal illness, e.g. chorio amnionitis, polyhydramnios, pre-eclampsia, diabetes mellitus. Premature rupture of membrane s. Uterine malformation or cervical incompetence. Placental disease, e.g. dysfunction, ante partum hemorrhage. Poor maternal health or socio-economic status. \200 \200 \200 Associated problems \200 Respiratory: surfactant de \201 ciency causing respiratory distress syndrome (RDS; b p.150 ), apnoea of prematurity (b p.154), chronic lung disease/bronchopulmonary dysplasia (CLD/BP D) (b p.166). CNS: intraventricular hemorrhage, periventricular leucomalacia; retinopathy o f prematurity (b p.188). GI: tolerance. Hypothermia. Immuno-compromise resulting in Impaire d \202 uid/electrolyte homeostasis ( loss, poor renal function). b p.169). Patent ductus arteriosus ( b p.192). Anemia of prematurity ( Jaundice (liver enzyme immaturity; Birth tra uma ( Perinatal hypoxia ( Later: increased risk of adverse neurodevelopmental outcome, beha vioral problems, sudden infant death syndrome (SIDS), non- accidental injury (NAI), and/or parental marriage break up (due to impaired infant \200\223maternal bonding, stress of long -term complications, etc.). necrotizing enterocolitis (b p.178); inability to suck; and poor milk \200 \200 i risk and severity of infection. i transepidermal skin water \200 \200 \200 \200 \200 b p.130). b p.126). b p.120). General management \200\224antenatal \200 Delivery should be planned in a center capable of caring for preterm infants. If a woman ha s threatened preterm labor in a center unable to care for the baby, possible in-utero trans fer should involve discussion between neonatology and obstetrics teams preferably at consul tant level. Consider fetal \201 bronectin screening to aid diagnosis and tocolysis to del ay birth to allow for transfer. Give mother IM corticosteroids, 2 doses, 12 \200\22324hr ap art, of either beta- or dexamethasone, if <34wks gestation. Steroids d mortality by up to 4 0% (d severity of RDS, periventricular hemorrhage, and necrotizing enterocolitis) provided they are given >24hr before birth. Bene \201 t persists for at least 7 days. Effect of rep eated doses remains unclear \200\224may have adverse impact on later growth. 06_McClure_06.indd 114 11/14/2012 11:22:40 PM PREMATURITY 115 General management \200\224postnatal \200 Most preterm infants require stabilization and support in transition \200\223 not resuscita tion. Senior pediatrician should be present at birth if very preterm, e.g. <28wks. Delay co rd clamping for 1min if infant not compromised. Immediately after birth, place in food grad e plastic bag and under radiant heater. Provide respiratory support as required: \200 \200 \200 2O); use positive end-expiratory pressure (PEEP) (5cmH start with lower peak inspiratory pressur e or proximal (PIP) (20cmH2O); consider elective intubation and ETT surfactant if <27/40; m ay be possible to stabilize with PEEP/nasal continuous positive airway pressure (CPAP) only . \200 Monitor oxygen saturation levels if available (right wrist = pre-ductal), and target oxygen therapy appropriately: \200 must be familiar with normal values; \200 approx 10% well preterm infants will have SpO \200 (cid:1) \200\230correct \200\231 starting dose of O2 unclear, therefore, can start in air; \200 Once stable, well infants >1800g, and >35/40 m ay be transferred to a suitable postnatal ward if midwifery staf \201 ng and expertise exi sts for the required additional care. Otherwise admit to a neonatal unit. Measure weight an d temperature on admission and monitor closely: \200 \200 \200 Monitor and maintain b lood glucose with enteral feeds (expressed breast milk), total parenteral nutrition (TPN) o r 10% glucose as appropriate. Encourage ALL mothers to express breast milk from day 1. Star t broad spectrum antibiotics if any possibility of infection, e.g. benzylpenicillin, and ge ntamicin. Start speci \201 c treatment for associated diseases and complications of premat urity, e.g. surfactant for RDS. Aim for minimal handling of infant with appropriate levels of noise and cycled lighting in the nursery. Support parents. 2 <70% at 5min; 2. easy to hyperoxygenate if start in high FiO <1000g 37 \200\22337.5C; >1000g 36.5 \200\22337C; nurse in 80% humidity for \201 rst 7 da ys if <30/40. 06_McClure_06.indd 115 11/14/2012 11:22:40 PM CHAPTER 6 Neonatology 116 Birth at the limit of viability WHO de \201 nes the perinatal period as starting at 22wks gestation, which is realistically the earliest gestation of viability. In the UK threshold viability is generally accepted to be when birth is between 22 and 25 completed weeks gesta tion, typically 500 \200\2231000g birth weight. Management before birth As gestation falls, the likelihood of mortality and serious long-te rm dis- ability increases. When preterm birth at threshold viability is threatened there sh ould be close collaboration between pediatrician, obstetrician, midwife, and family. Unless delivery is precipitate a senior pediatrician should meet parents before birth to assess and do the following: \200 \200 \200 \200 \200 \200 Ascertain whether estimate of gestation is likely to be reliable. Give relevant information . Outline potential problems. Outline possible management (including option of not resuscit ating). Describe relevant survival and disability rates. Parents should fully participate i n any decision about the appropriateness of any later attempted resuscitation. Management at birth \200 <22wks bene \201 cial for a senior pediatrician to attend birth to reassure parents and su pport staff in provision of comfort care. 22 \200\2232 present to assess size, maturity, an d condition of the newborn and then manage appropriately. If an infant appears viable, resp iratory support should be given. External cardiac massage or resuscitation drugs are not ge nerally considered appropriate. If junior doctors are present alone at such a delivery full resuscitation should be started and continued until a senior pediatrician arrives and make s an assessment. If parents do not wish life-sustaining care in an infant born before 25wks their view should be respected and taken into account. However, if the infant appears unex pectedly vigorous or more mature, full treatment should be started. gestation: rarely suitable for resuscitation, but it may still be 5wks gestation: a senior obstetrician and pediatrician should be If resuscitation is withheld on a delivery ward the infant should be kept warm and comforta ble, as well as offered to parents to cuddle. For man- agement after death see b p.198. Management after birth Clinical progress after the initial resuscitation and further discus sion with the parents will dictate whether it is appropriate to continue or withdraw life-s ustaining treatment. Where doctors and parents, or parents them- selves, cannot agree as to the best or most appropriate management it is almost always best to continue as the situat ion will become clearer with time and agreement is usually then reached. 06_McClure_06.indd 116 11/14/2012 11:22:40 PM OUTCOME FOLLOWING PREMATURITY 117 Outcome following prematurity Risk of complications and associated morbidity/mortality stea dily lessen as gestation advances. Infants who are well in the \201 rst 24hr and are >32w ks gestation are at low risk of suffering adverse outcomes. The EPICure and EPICure2 studie s give the best available guide to likely outcome in UK for infants born at less than 26wks gestation (Table 6.1).1 Table 6.1 Likely outcomes in UK for infants born at <26wks gestation Weeks of gestation Survival to discharge (%) 22 \200\22323 24 25 1995 19 35 54 2006 26 47 67 Statistically signi \201 cant increase? No Yes+ Yes++ Overall survival of live births free of disability at age 6yrs (%)EPICure 1 <0.5 9 20 Disabled survivors in EPICure were categorized as approximately; 1/3 Severe, 1/3 Moderate, 1/3 Mild. The overall rate of severe IVH (13 \200\22315%) or chronic lung disease (74 \200 \22375%) was unchanged between 1995 and 2006. Typical disabilities were; Cerebral palsy, most commonly spastic (diplegia > quadriplegia > hemiplegia). Squint (strabismus). Blindness. Hearing loss. Epilepsy. Cognitive impairment and behavioral disorders, e.g. attention de \201 cit hyperactivity disorder. \200 \200 \200 \200 Generally smaller, more immature infants will have a poorer outcome than larger, mature bab ies. Knowledge of your own unit \200\231s outcome is important. However, the numbers will be sma ll, and national \201 gures (where available) should be used. Note that many things in \202 uence outcome, e.g. a singleton infant, born spontaneously at 25wks gestation after an otherwise uncomplicated pregnancy in a mother treated with 48hr of steroids, has a better prog- nosis than a triplet born suddenly at 26wks after the mother developed severe chorioa mnionitis. Reference 1 Marlow, N., Wolke, D., Bracewell, et al. (2005). Neurologic and developmental d isability at six years of age after extremely preterm birth. N Engl J Med 352: 71 \200\2232. 06_McClure_06.indd 117 11/14/2012 11:22:40 PM CHAPTER 6 Neonatology 118 Basic obstetrics The aim of obstetrics is to monitor and promote fetal and maternal well- b eing during pregnancy and labor, and to identify and manage high risk pregnancies or compli cations. In the UK most women choose to deliver in hospital, although planned home deliveri es are on the increase. Depending on local provision women may also choose to deliver in a birthing center, community midwifery unit, or midwife-led unit attached to an obstetric cen ter. All \200\230high-risk \200\231 deliveries should be in a consultant-led obstetric unit, an d clear protocols should be in place for the transfer in of women from outly- ing centers i f problems arise during labor. Routine antenatal care of the low risk pregnancy In the UK, care is usually shared among GP , community midwife, and ob- stetrician. \200 First antenatal ( \200\230booking \200\231) visit usually occurs at 10 \200\22312wks gestat ion when signi \201 cant risk factors should be identi \201 ed. Fetal US is usually perfo rmed to determine gestational age. Women are assessed every few weeks to monitor: \200 \200 \200 \200 general health; hemoglobin (Hb); BP, urine glucose and albumin; fetal growth, movements, HR , and lie (liquor volume). Routine prenatal screening Maternal testing is offered for: \200 \200 Blood group and antibodies (iso-immune haemolytic disease); Serology for syphilis, rubella, hepatitis B, and human immunode \201 ciency virus (HIV); Urine for protein, glucose, and bacteria. Blood tests are also offered at 17 \200\22318wks to screen for chromosomal dis- orders and structural anomalies. Controversy exists as to what is most cost-effective and they may inc lude: \200 \200 \200 \200 \200 fetoprotein (AFP); Human chorionic gonadotrophin (hCG); Oestriol (combined with above 2 tests = \200\230tripl e test \200\231); Triple test plus inhibin ( \200\230quadruple test \200\231); Quadruple te st plus pregnancy-associated protein-A (PrAP-A) nuchal thickness. US A detailed fetal US looking for abnormalities is usually done at 718wks. Chorionic villus biopsy (>10wks gestation) or amniocentesis (usually at 15 \200\22316wks) i s offered for chromosomal, enzymatic, or gene probe analy- sis, if screening tests show hig h risk of serious problems (also if maternal age >35yrs, previously abnormal baby, +ve fami ly history). Both diagnostic tests carry a risk of miscarriage (71%, slightly higher with c ardiovascular system (CVS)). 06_McClure_06.indd 118 11/14/2012 11:22:40 PM BASIC OBSTETRICS 119 Induction of labor Indicated when delivery is safer for either mother or baby than to remai n in utero. Method: use prostaglandin (PO or vaginally, per vagina (PV)) or amniotomy. Normal labor Occurs >37wks and should result in delivery within 24hr of starting. \200 st age: from the onset of labor to full cervical dilatation. Once 1st cervix is 3cm dilated should then be at least 1cm/hr. 2nd stage: time from fully dilate d cervix to birth. Normal duration is 45 \200\223120min in a primiparous woman; 15 \200\223 45min if multiparous. Active pushing during the second stage should not usually exceed 60 \200\22390min. 3rd stage: time from birth to placental delivery. Intrapartum fetal assessment Intrapartum fetal heart monitoring detects signs of fetal comp romise: \200 In established low-risk labor intermittent auscultation (by Doppler USS, or Pinard stethoscope) should be undertaken for 1min after contractions, at least every 15min in the \201 rst stage and every 5min in the second stage. Continuous electronic fetal mon itoring (cardiotocogram) should be undertaken in high risk pregnancies and when: \200 \200 \200 \200 \200 Fetal blood sampling is indicated if fetal distress suspected. abnormal fetal HR detected; meconium staining of liquor or bleeding in labor; maternal pyre xia; oxytocin use; maternal request. Mode of delivery Majority of term infants are delivered by normal vaginal delivery. Indicat ions for cesarean section (CS) include: \200 \200 \200 \200 \200 \200 \200 \200 \200 \200 \200 \200 \200 maternal ill health; acute fetal distress; antepartum hemorrhage (APH); placenta praevia; u mbilical cord prolapsed; failure to progress; failed induction; previous CS; fetal malprese ntation (including breech); multiple pregnancy; pregnancy-induced hypertension; maternal HI V or HSV; evidence of ongoing fetal compromise, e.g. severe IUGR. Instrumental delivery (forceps or vacuum extraction) may be indicated when there is: \200 \200 \200 prolonged 2nd stage; malpresentation, e.g. breech delivery or occipital-posterior; fetal di stress. 06_McClure_06.indd 119 11/14/2012 11:22:40 PM CHAPTER 6 Neonatology 120 Obstetric problems It is desirable for a pediatrician to attend a birth if there is: \200 \200 \200 \200 \200 \200 \200 \200 \200 fetal distress (including meconium-stained liquor); emergency CS; elective CS under general anesthetic (GA); vaginal breech delivery; rotational forceps; preterm delivery <34wks gest ation; severe IUGR; maternal IDDM; serious fetal abnormality; signi \201 cant iso-immune h aemolytic disease. Small for gestational age See b p.111. Serial detailed US scans (including Doppler fetal um bilical and cerebral artery blood \202 ow measurement) should be performed to determine: \200 Whether growth reduction is symmetrical or asymmetrical. Symmetrical SGA is usually fetal i n origin; asymmetrical suggests placental dysfunction. Fetal growth rate. Fetal health. \200 There is i risk of fetal hypoxia or death, requiring close antenatal and intrapartum monitoring. Early delivery may be needed. Abnormal Doppler artery measurements (e.g. absen t or reversed end diastolic \202 ow) indicate an especially high fetal risk. Large for gestational age See b p.112. A glucose tolerance test should be performed to dete ct maternal diabetes. Because of i risk of obstetric complications, a senior obstetrician s hould supervise timing and mode of delivery and labor. Specialist input (diabetologist) sho uld also be sought early. Multiple pregnancy There is an increased risk of: \200 \200 \200 \200 \200 \200 \200 \200 Perinatal mortality. Preterm delivery. Malformations. Malpresentation. Polyhydramnios. Preg nancy-induced hypertension. APH. Risk increases as fetus number increases. may be indicated to improve outcome for survivors. (cid:1) If (cid:2)3, selective feticide 06_McClure_06.indd 120 11/14/2012 11:22:41 PM OBSTETRIC PROBLEMS 121 Oligohydramnios Liquor volume <500mL. Causes: \200 \200 \200 Placental insuf \201 ciency. Preterm prolonged rupture of membranes (PPROM). Fetal urinary tract obstruction or renal disease (e.g. Potter \200\231s syndrome: b pp.370, 951). Risks \200 \200 Pulmonary hypoplasia/dry lung syndrome. Contractures/developmental dysplasia of the hip. Polyhydramnios Liquor volume >2000mL. Causes: \200 \200 \200 s to fetal disease, e.g. upper GI tract obstruction. 50% 30% idiopathic. 20% maternal diabetes mellitus. Risks \200 \200 \200 \200 Preterm labor. Malpresentation. Umbilical cord prolapse. APH. Amniotic \202 uid reduction and indomethacin may be bene \201 cial. Prolonged pregnancy Longer than 42wks gestation. \200 i perinatal mortality and morbidity (i risk of perinatal Signi \201 cant hypoxia due to placental insuf \201 ciency, obstructed labor due to large r fetus, meconium aspiration, reduced skull molding). Induction of labor is usually advised after 41wks. Antepartum hemorrhage Uterine-placental bleeding after 24wks gestation. \200 \200 \200 with i perinatal mortality and morbidity; preterm delivery. Associated Major causes are placenta praevia, vasa praevia, placental abruption. Observatio n or immediate delivery performed depending on severity and gestation. Umbilical cord prolapse An obstetric emergency due to high risk of cord compression and per ina- tal asphyxia. Requires urgent delivery, usually by CS. Preterm prelabour rupture of the membranes \200 \200 In 80% preterm labor rapidly follows. In remaining 20% there is occurs before 20wks, neonat al pulmonary hypoplasia. Treatment Tocolysis is contraindicated. signi \201 cant risk of infection and, if PPROM : Give mother corticosteroids. Consider antibiotics. Preterm labor See b p.114 and p.116 06_McClure_06.indd 121 11/14/2012 11:22:41 PM CHAPTER 6 Neonatology 122 Failure to progress Neonatal and maternal morbidity increase with progressive delay. \200 Caused by: passage obstruction (malpresentation, cephalopelvic disproportion, abnormal pel vic, or cervical anatomy) or uterine dysfunction. Treatment synthetic oxytocin to hasten de livery. CS may be necessary. : arti \201 cial rupture of membranes (ARM), analgesia, and Disturbing/abnormal fetal heart rate patterns May signify hypoxia. Fetal acidosis results i f hypoxia prolonged or re- peated. Signs \200 \200 Loss of variability in baseline fetal heart rate (<5beats/min). Late decelerations (in hear t rate) (lowest fetal heart rate is >30s after peak uterine contraction). Repetitive severe , variable decelerations. Prolonged fetal deceleration (2 \200\2239min below established ba seline). Prolonged fetal bradycardia (<100/min). Persistent fetal tachycardia (>170/min). \200 \200 \200 Tests \200 (cid:1) 7.24 = \200\230Borderline \200\231 - repeat (cid:1) 30min; Fetal blood gas sampling (pH (cid:1)7.2 = \200\230Abnormal \200\231 \200\224consultant obs tetrician and delivery). Postnatal umbilical artery and venous blood gas are used to determ ine the actual level and nature of acidaemia. Malpresentation Most common form is breech (3% at term). \200 Types: knees \202 exed); footling (feet are presenting part). External and 36wks. Vaginal morbidity; CS is recommended. Other malpresentations are associated with labor and CS rate (obligatory for brow and transverse presentation). extended (hips \202 exed and knees extended); \202 exed (hips and cephalic version: may be successful in turning baby between 34 breech delivery: associated with i perinatal mortality and i risk of obstructed Shoulder dystocia Inability to deliver shoulders after head has been delivered. Cord com- p ression leads to rapid fetal asphyxia. \200 Treatment: maneuver ( \202 exion + abduction maternal hips, thighs on abdomen), suprapubic pressure, posterior fetal arm extraction, +/ \200\223 episiotomy : perinatal asphyxia, hum eral and clavicle fracture, Erb \200\231s palsy. Risks urgent delivery \200\224experienced obstetrician, McRobert \200\231s 06_McClure_06.indd 122 11/14/2012 11:22:41 PM OBSTETRIC PROBLEMS 123 06_McClure_06.indd 123 11/14/2012 11:22:41 PM CHAPTER 6 Neonatology 124 Maternal disorders causing neonatal disease Any maternal disease can adversely affect fetal and neonatal health. Certain maternal illnesses, e.g. CHD, also raise the risk of inherita nce in the newborn. Most common manifestations are: \200 \200 \200 Spontaneous abortion. Fetal death. IUGR and/or preterm delivery. Maternal drug ingestion Maternal medications or substance abuse can affect the newborn: \200 b p.951); \200 \200 \200 maternal anticonvulsants ( alcohol abuse and fetal alcohol syndrome ( tobacco; neonatal abs tinence syndrome ( b p.951); b p.186). Hypertensive diseases Pregnancy-induced hypertension (e.g. pre-eclampsia, eclampsia, haemol yt- ic anemia \200\223elevated liver enzymes \200\223low platelet count (HELLP) syndrome) i s associated with increased fetal loss, the need for preterm delivery, IUGR, neonatal leuco penia, and thrombocytopenia. Maternal drug treat- ment may cause neonatal hypoglycaemia and hypotension. Systemic lupus erythematosus Associated with: i \200 \200 \200 \200 Risk of spontaneous abortion. IUGR. Preterm delivery. Neonatal lupus syndrome (rare; associated with anti-Ro and \200 \223La antibodies): complete heart block, haemolytic anemia, leucopenia, thrombocytopenia, and discoid erythematous skin rash. Antiphospholipid syndrome Maternal antiphospholipid antibodies (e.g. lupus anticoagulant or anticardiolipin antibodies) are associated with spontaneous abortion, IUGR, fetal death, n eed for preterm delivery. Thyroid disease See b p.425. In 710% of women with Graves \200 \231s disease, thyroid-stimulating hormone (TSH) receptor-stimulator antibodies cross the p lacenta causing neonatal thyrotoxicosis. Fetus most likely to be affected if high maternal IgG se- rum level develops, or mother requires treatment during pregnancy. Take cord blood for TSH, fT4, and TSH receptor antibody (TRAB). Repeat at D5 if results abnormal. Myasthenia gravis In 710% transplacental passage of IgG antibodies to motor end-plate ace- tylcholine receptors causes transient neonatal myasthenia gravis. Diabetes mellitus See b p .112 Maternal infection See b pp.184 \200\223185 06_McClure_06.indd 124 11/14/2012 11:22:41 PM MATERNAL DISORDERS CAUSING NEONATAL DISEASE 125 06_McClure_06.indd 125 11/14/2012 11:22:41 PM CHAPTER 6 Neonatology 126 Birth trauma Risk factors LGA, cephalic \200\223pelvic disproportion, malpresentation, prec ipitate delivery, instrumental delivery, shoulder dystocia, prematurity. Head \200 Caput succedaneum: particularly large following ventouse delivery (chignon). Rapidly resolv es. Cephalhaematoma: bleed(s). Most often occur over parietal bones. Swelling limited by su ture lines. Resolves over weeks. Subaponeurotic haematoma: periostium, so can be large and life-threatening. Presents as \202 uctuant scalp swelling, not limited by suture lines. oedema of the presenting scalp. Can be common \202 uctuant swelling(s) due to subperiostial rare; bleeding not con \201 ned by skull Skin \200 \200 Traumatic cyanosis: Lacerations: pH sampling, or scalpel wounds during CS. Close with Steri -Strips or suture if required. bruising and petechiae of presenting part. caused by forceps, ventouse cap, scalp electrode s, scalp Nerve palsies \200 Brachial plexus: result from dif \201 cult assisted delivery (e.g. shoulder dystocia); the arm is \202 accid with pronated forearm and \202 exed wrist (waiter \200\231s tip posi tion). Complete recovery occurs within 6wks in two-thirds of cases. X-ray clavicle to exclu de fractures. Refer to physiotherapy for assessment and follow-up. Facial nerve palsy: spin e or forceps. Presents as facial asymmetry that is worse on crying (affected side shows lac k of eye closure and lower facial movement; mouth is drawn to normal side). Majority recove r in 1 \200\2232wks. May require eye care with methylcellulose and specialist referral. commonest is Erb \200\231s palsy (C5 \200\223C6 nerve routes). May follows pressure on face from either maternal ischial Fractures \200 Clavicle \200 Long bone fractures: usually lower avulsion fractures of t he femoral or tibial epiphyses, or mid-shaft fractures of the femur or humerus. Infant pres ents as unsettled, with affected limb pseudo-paralysis, or obvious deformity or swelling. C on \201 rm by X-ray. Skull fracture: treatment unless depressed in which case neurosurgica l referral is required. Treatment: analgesia; limb immobilization (arm inside baby-grow), o ften do not require orthopedic intervention, healed in a few weeks. Rapid healing and remod eling usually occur. (commonest). associated with forceps delivery and usually require no 06_McClure_06.indd 126 11/14/2012 11:22:41 PM BIRTH TRAUMA 127 Soft tissue trauma \200 