Ebook Key topics in neonatology (2/E): Part 1

(BQ) Part 1 book “Key topics in neonatology” has contents: Assessment of gestational age, blood pressure, childbirth complications and foetal outcome, chromosomal abnormalities, chromosomal abnormalities, congenital diaphragmatic hernia, extreme prematurity,… and other contents.

Key Topics in Neonatology Key Topics in Neonatology Second Edition Richard Mupanemunda BSc BM MRCP(UK) FRCPCH Consultant Neonatologist Birmingham Heartlands Hospital NHS Trust Honorary Senior Clinical Lecturer University of Birmingham, UK Michael Watkinson MB BChir MA FRCP FRCPCH Consultant Neonatologist Birmingham Heartlands Hospital NHS Trust Honorary Senior Clinical Lecturer University of Birmingham, UK LONDON AND NEW YORK A MARTIN DUNITZ BOOK © 2005 Taylor & Francis, an imprint of the Taylor & Francis Group First edition published in the United Kingdom in 1999 by BIOS Scientific Publishers Limited This edition published in the Taylor & Francis e-Library, 2005 “To purchase your own copy of this or any of Taylor & Francis or Routledge's collection of thousands of eBooks please go to www.eBookstore.tandf.co.uk.” Second edition published 2005 by Taylor & Francis, an imprint of the Taylor & Francis Group, Park Square, Milton Park, Abingdon, Oxon OX14 4RN Tel.: +44 (0) 20 7017 6000 Fax.: 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accuracy, no respons ibility for loss or injury whatsoever occasioned to any person acting or refraining from action as a result of information contained herein can be accepted by the authors or publishers The reader should remember that medicine is a constantly evolving science and while the authors and publishers have ensured that all dosages, applications and practices are based on current indications, there may be specific practices which differ between communities You should always follow the guidelines laid down by the manufacturers of specific products and the relevant authorities in the country in which you are practising A CIP record for this book is available from the British Library Library of Congress Cataloging-in-Publication Data Data available on application ISBN 0-203-50534-4 Master e-book ISBN ISBN 0-203-59745-1 (Adobe eReader Format) ISBN 85996 234 (Print Edition) Distributed in North and South America by Taylor & Francis 2000 NW Corporate Blvd Boca Raton, FL 33431, USA Within Continental USA Tel.: 800 272 7737; Fax.: 800 374 3401 Outside Continental USA Tel: 561 994 0555; Fax.: 561 361 6018 E-mail: orders@crcpress.com Distributed in the rest of the world by Thomson Publishing Services Cheriton House North Way Andover, Hampshire SP10 5BE, UK Tel.: +44 (0)1264 332424 E-mail: salesorder.tandf@thomsonpublishingservices.co.uk Composition by Wearset Ltd, Boldon, Tyne and Wear Contents Preface to the first edition Preface to the second edition List of abbreviations x xii xiv Abdominal distension Abdominal wall defects Acid-base balance Acute collapse Anaemia Anaesthesia and postoperative analgesiaa Apnoea and bradycardia Assessment of gestational age Birth injuries Bleeding disorders Blood-glucose homeostasis Blood pressure Breast-feeding Cardiac arrhythmiasb Cerebral palsy Childbirth complications and foetal outcome Chromosomal abnormalities Chronic lung disease Complications of mechanical ventilation Congenital diaphragmatic hernia Congenital heart disease—congestive heart failureb Congenital heart disease—cyanotic defectsb Congenital malformations and birth defects The death of a baby Discharge planning and follow-up Extracorporeal membrane oxygenation Extreme prematurity Feeding difficulties Fluid and electrolyte therapy Gastrooesophageal reflux 12 15 20 24 28 30 35 43 49 54 60 64 72 77 87 94 97 102 107 113 117 121 125 129 136 140 144 Germinal matrix-intraventricular haemorrhage Haemolytic disease Head size Hearing screening Heart murmurs in neonatesb Hepatitis B and C Herniae Hirschsprung’s disease HIV and AIDS Home oxygen therapy Hydrocephalus Hydrops fetalis Hypotonia Hypoxic-ischaemic encephalopathy Immunisations Infants of diabetic mothers Infection—general Infection—neonatal Infection—perinatal Infection—prenatal Inherited metabolic disease—investigation and management Inherited metabolic disease—recognisable patterns Intrauterine growth restriction Intubation Jaundice Jitteriness Liver disorders Maternal drug abuse Mechanical ventilation Meconium aspiration syndrome Metabolic acidosis Multiple pregnancy Necrotising enterocolitis Neonatal screening for inherited disease Neonatal surgery Neural tube defects Neurological evaluation Neuromuscular disorders—muscular Neuromuscular disorders—neurological Nitric oxide therapy Nutrition 148 152 156 159 163 165 169 171 175 182 184 187 192 195 200 205 209 214 220 227 232 238 243 248 251 258 260 267 272 278 282 287 291 294 298 301 306 310 315 320 325 Oesophageal anomalies Orthopaedic problems Outcomes of neonatal intensive care Patent ductus arteriosus Periventricular leucomalacia Persistent pulmonary hypertension of the newborn Polycythaemia Postnatal examination Pregnancy complications and foetal health Prenatal diagnosis Pulmonary air leaks Pulmonary haemorrhage Pulmonary hypoplasia Renal and urinary tract disorders—nephrology Renal and urinary tract disorders—urology Respiratory distress Respiratory distress syndrome Resuscitation Retinopathy of prematurity Sedation and analgesia on the neonatal intensive care unit Seizures Sexual ambiguity Shock Skin disordersc Stridor Surfactant replacement therapy Surgical emergencies Thermoregulation Trace minerals and vitamins Transfusion of blood and blood products Transport of sick neonates Vomiting 329 332 336 343 348 352 358 362 365 373 377 380 383 387 395 401 406 412 419 424 428 433 438 440 444 447 451 455 458 464 470 475 Index 478 a Contributed by R.Danha, Specialist Registrar in Anaesthetics, Nuffield Department of Anaesthetics, John Radcliffe Hospital, Oxford, UK b Contributed by M.Chaudhari, Consultant Paediatric Cardiologist, Freeman Hospital, Newcastle Upon Tyne, UK c Contributed by H.Goodyear, Consultant Paediatrician, Birmingham Heartlands Hospital, Birmingham, UK Key topics in neonatology 236 Specific therapies Peritoneal dialysis, haemodialysis, and exchange transfusion (with fresh blood) may be useful in some IMDs where the accumulation of toxic metabolites is detrimental (organic acidurias and urea cycle defects) Adequate nutrition suppresses endogenous tissue breakdown At the earliest opportunity, enteral or total parenteral nutrition should be commenced with appropriate glucose, lipid, and amino acids and mixtures built up to provide the recommended dietary allowance (RDA) • Insulin infusion (0.2–0.3 units/kg per h) when combined with high glucose concentration (such as unit insulin per g of glucose), may suppress catabolism • Sodium benzoate (250–500 mg/kg per day) and sodium phenylbutyrate (250–650 mg/kg per day) may be useful in urea cycle defects by enhancing nitrogen excretion as hippurate and phenylacetylglutamine, respectively • Arginine becomes an essential amino acid in urea cycle defects and therefore requires supplementation (at doses of 100–150 mg/kg per day) to maintain plasma concentrations of 50–200 µmol/l Alternatively, substitute citrulline (up to 700 mg/kg per day) for arginine • L-Carnitine (100 mg/kg per day), orally or intravenously, is useful in organic acidaemias (propionic, isovaleric, and methylmalonic acidaemias, and 3-methylcrotonyl glycinuria), as it enhances specific acylcarnitine excretion • Dichloroacetate (DCA), a potent inhibitor of pyruvate dehydrogenase kinase, is useful in congenital lactic acidosis unresponsive to other therapies All severe hyperlacticacidaemias (primary or secondary) are responsive to DCA (50 mg/kg per day) Long-term outcome Despite several advances in the diagnostic techniques for these disorders, the long-term outlook remains largely poor Most patients with urea cycle defects and hyperammonaemia have a very poor outcome, most survivors being handicapped Those known to be affected prenatally may initially better if treated expectantly, but a favourable long-term outlook may be secured only by liver transplantation The organic acidaemias generally have a poor outcome, and affected infants may benefit significantly only from liver transplantation or futuristic gene therapy Isovaleric acidaemia has a better outlook than the other acidaemias, with neurodevelopmental outcome depending on early diagnosis and compliance with treatment With early diagnosis and meticulous therapy, infants with maple syrup urine disease (MSUD) can be expected to survive long term with at times satisfactory neurodevelopmental outcomes The excellence of longterm metabolic control and length of time after birth for which the plasma leucine levels were above mmol/l directly influence intellectual outcome Useful website www.ssiem.org.uk/bimdg.html Inherited metabolic disease 237 British Inherited Metabolic Disease Group and Society for the Study of Inborn Errors of Metabolism (includes the UK directory of laboratories diagnosing inborn errors of metabolism) Further reading Burton BK Inborn errors of metabolism in infancy: a guide to diagnosis Pediatrics (1998) 102:E69 Chaves-Caballo E Detection of inherited neurometabolic disorders: a practical clinical approach Pediatric Clinics of North America (1992) 39:801 Greene CL, Goodman SI Inborn errors of metabolism In: WW Hay, JR Groothuis, AR Hayward et al (eds) Current Pediatric Diagnosis and Treatment, 13th edn Stamford, CT: Appleton & Lange, 1997:864 Hoffman GF, Nyhan WL, Zschocke J et al Inherited Metabolic Diseases Philadelphia: Lippincott, Williams & Wilkins, 2001 Ogier de Baulny H, Saudubray JM Emergency treatments In: J Fernandes, JM Saudubray, G Van den Berghe (eds) Inborn Metabolic Disease: Diagnosis and Treatment, 2nd edn New York: Springer-Verlag, 1995:47–55 Saudubray JM, Narcy C, Lyonnet L et al Clinical approach to inherited metabolic disorders in neonates Biology of the Neonate (1990) 58:44 Saudubray JM (ed.) Inborn errors of metabolism Seminars in Neonatology (2002) 7(1) Related topics of interest • acute collapse • death of an infant • inherited metabolic disease—recognisable patterns • prenatal diagnosis Inherited metabolic disease—recognisable patterns Several clinical signs and laboratory findings are especially valuable in diagnosing inherited metabolic diseases (IMDs) The following patterns may be recognised Altered neurological status Toxic type with hypertonia and abnormal movements Principal investigations Urine and plasma amino acid chromatography Findings Urine DNPH strongly positive, no acidosis, and minor or no acetonuria Normal lactate, glucose, and calcium Ammonia normal or raised Usual diagnoses Maple syrup urine disease (characteristic smell) Toxic type with dehydration Principal investigations Urine and plasma organic acid chromatography, plasma and urine carnitine esters, and plasma carnitine Findings Moderate acetonuria and acidosis Urine DNPH slightly positive or negative Ammonia raised Lactate normal or raised; glucose and calcium normal or raised Leucopenia and thrombocytopenia Usual diagnosis Ketolytic defects, organic acidurias (isovaleric acidaemia, propionic acidaemia, and Inherited metabolic disease 239 methylmalonic acidaemia) Energy-deficiency type with liver or cardiac symptoms Principal investigations Plasma and urine organic acids, plasma carnitine, loading or fasting test, and fatty acid oxidation studies on lymphocytes or fibroblasts Findings Acidosis without acetonuria and urine DNPH negative Lactate and ammonia raised with low/normal calcium or glucose, and normal blood count Usual diagnoses Fatty acid oxidation and ketogenesis defects Energy-deficiency type, hypotonia, and tachypnoea Principal investigations Lactate/pyruvate ratios, hydroxybutyrate/acetoacetate ratio, urine organic acids, and enzyme assays (muscle, fibroblast, or lymphocytes) Findings Marked acidosis, acetonuria, and lacticacidaemia Ammonia normal or raised Normal calcium and glucose Usual diagnoses Multiple carboxylase deficiency and congenital lactic acidosis (pyruvate carboxylase, pyruvate dehydrogenase, Krebs cycle, and respiratory chain) Toxic type, hypotonia, seizures, coma, and moderate hepatocellular disturbances Principal investigations Plasma and urine amino acids, urine organic acids, and liver or intestinal enzyme studies (such as ornithine carbamyl transferase and carbamyl phosphate synthetase) Key topics in neonatology 240 Findings Alkalosis without acetonuria and DNPH negative Ammonia raised, lactate normal or raised with normal blood glucose, calcium, and blood count Usual diagnoses Urea cycle defects and fatty acid oxidation defects (glutaric aciduria type II, carnitine palmitoyltransferase II, long-chain acyl-CoA dehydrogenase, and 3-hydroxy long-chain acyl-CoA dehydrogenase) Severe hypotonia, myoclonic jerks, and seizures Principal investigations Amino acid chromatography, CSF amino acids, plasma phytanic acid, and plasma very long chain fatty acids Findings No acidosis, and acetonuria and DNPH negative Ammonia, lactate, glucose, and blood count all normal Usual diagnoses NKH, sulphite oxidase, xanthine oxidase, peroxisomal disorders, pyridoxine dependency, and trifunctional enzyme Hepatomegaly with deranged liver function Hepatomegaly and hypoglycaemia Principal investigations Fasting and loading tests Liver, fibroblast, and lymphocyte enzyme studies Findings Acetonuria with acidosis Ammonia normal, lactate raised, moderate hypoglycaemia, and normal blood count Inherited metabolic disease 241 Typical diagnoses Fructose diphosphatase deficiency, glycogenosis type I (Acetest negative), and glycogenosis type III (moderate acetonuria) Hepatomegaly, jaundice, liver failure, and hepatocellular necrosis Principal investigations Enzyme studies to exclude galactosaemia, fructosaemia, and tyrosinaemia Urinary organic acids Findings Slight acidosis and acetonuria Ammonia normal or raised, lactate significantly raised, and glucose normal or decreased Typical diagnoses Galactosaemia, fructosaemia, tyrosinosis type I, neonatal haemochromatosis, and respiratory chain disorders Hepatomegaly, cholestatic jaundice, chronic diarrhoea, and failure to thrive Principal investigations Plasma and urine organic acids, protein electrophoresis, phytanic acid, very long-chain fatty acids, pipecolic acid, and phytanic acid Findings Acidosis and ketosis are absent with normal glucose, lactate, and ammonia Typical diagnoses α1-Antitrypsin deficiency, peroxisomal disorders, and inborn errors of bile acid metabolism Hepatosplenomegaly, storage signs, chronic diarrhoea, and failure to thrive Principal investigations Enzyme studies, mucopolysaccharides, sialic acid, and oligosaccharides Key topics in neonatology 242 Findings Acidosis and ketosis absent Ammonia and glucose normal with normal or raised lactate Typical diagnoses Storage disorders, gangliozide I, gangliosidosis, infantile sialic acid storage disease (sialidosis II), I-cell disease, mucopolysaccharidosis type VII, and galactosialidosis Useful websites www.ssiem.org.uk/bimdg.html British Inherited Metabolic Disease Group and Society for the Study of Inborn Errors of Metabolism (includes the UK directory of laboratories diagnosing inborn errors of metabolism) www.emedicine.com/emerg/topic768.htm eMedicine topic on inborn errors of metabolism eMedicine is one of the largest and most current online clinical knowledge bases available to health professionals www.neonatology.com Neonatology on the web—an extensive resource on neonatology Further reading Clarke JTR A Clinical Guide to Inherited Metabolic Diseases, 2dn edn Cambridge: Cambridge University Press, 2003 Lyon G, Adams RD, Kolodny EH Neurology of Hereditary Metabolic Diseases of Children, 2nd edn New York: McGraw-Hill, 1996 Saudubray JM, Ogier H, Charpentier C Clinical approach to inherited metabolic diseases In: J Fernandes, J-M Saudubray, G Van den Berghe (eds) Inborn Metabolic Disease: Diagnosis and Treatment, 2nd edn New York: Springer-Verlag, 1995:3–39 Saudubray JM (ed.) Inborn errors of metabolism Seminars in Neonatology (2002) 7(1) Scriver CR, Beaudet AL, Sly WS et al (eds) The Metabolic and Molecular Basis of Inherited Disease, 7th edn New York: McGraw-Hill, 1995 Wraith JE Inborn errors of metabolism in the neonate In: JM Rennie, NRC Roberton (eds) Textbook of Neonatology, 3rd edn Edinburgh: Churchill Livingstone, 1999:986– 1002 Related topics of interest • acute collapse • death of an infant • inherited metabolic disease—investigation and management • prenatal diagnosis Intrauterine growth restriction The provision of adequate nutrition for the growing foetus is essential for its normal development and has implications for future health and well-being during childhood and adulthood Intrauterine growth restriction (IUGR) is largely a consequence of foetal malnutrition It is well known that the lighter a newborn infant is at birth, the more likely it is to become ill or die Recently, convincing evidence has accumulated linking foetal malnutrition with increased morbidity and mortality from cardiovascular disease in adulthood Pathophysiology Most foetuses, including those in multiple gestations, follow similar growth curves during the first 20 weeks of pregnancy, with any slowing of growth usually occurring only in the second half of pregnancy Where the cause is physiological (such as multiple pregnancy or inherited genetic factors), slow growth is confined to the third trimester The more severe the pathology, the earlier foetal growth restriction becomes evident The earliest slowing of growth (during second trimester) occurs when the foetus is inherently abnormal (as in congenital or chromosomal anomaly) or has sustained significant first trimester insult (as from intrauterine infection or drug exposure) Recent studies have given considerable insight into the pathophysiology of IUGR At the start of gestation, growth appears to be controlled by nutritional input and growth factors acting locally by autocrine and paracrine mechanisms Among these, the insulinlike growth factors (IGFs, especially IGF-I) and their binding proteins (IGFBPs) appear to have a central regulatory role Foetuses showing IUGR have low IGF-I and IGFBP-3 levels but elevated growth hormone (GH) levels Following birth and renutrition, a rapid increase in IGF-I and a decrease in GH levels are observed Thus, GH, though playing a role in foetal and infantile growth, appears not to be the key hormone for foetal growth On the other hand, insulin appears to play a major role in the regulation of foetal growth, perhaps by increasing IGF-I production Definition Newborn infants may be described, according to their birth weight for gestation, as appropriate for gestational age (AGA), small for gestational age (SGA), or large for gestational age (LGA) The definition of SGA varies from a birth weight below the 10th percentile to one of less than the 3rd percentile In the UK, just over 2% of all babies may be SGA, whereas in some developing nations up to one in three newborns may be SGA and every other infant may be of low birth weight (LBW) (weighing