Robert M. Kliegman - Nelson Textbook of Pediatrics

21 EDITION

ROBERT M. KLIEGMAN, MD

Professor and Chair Emeritus

Department of Pediatrics

Medical College of Wisconsin

Milwaukee, Wisconsin

JOSEPH W. ST GEME III, MD

Professor of Pediatrics and Microbiology and Chair of the Department of Pediatrics

University of Pennsylvania Perelman School of Medicine

Chair of the Department of Pediatrics and Physician-in-Chief

Leonard and Madlyn Abramson Endowed Chair in Pediatrics

Children's Hospital of Philadelphia

Philadelphia, Pennsylvania

NATHAN J. BLUM, MD

William H. Bennett Professor of Pediatrics

University of Pennsylvania Perelman School of Medicine

Chief, Division of Developmental and Behavioral Pediatrics

Children's Hospital of Philadelphia

Philadelphia, Pennsylvania

SAMIR S. SHAH, MD, MSCE

Professor of Pediatrics

University of Cincinnati College of Medicine

Director, Division of Hospital Medicine

Chief Metrics Officer

James M. Ewell Endowed Chair

Cincinnati Children's Hospital Medical Center

Cincinnati, Ohio

ROBERT C. TASKER, MBBS, MD

Professor of Neurology

Professor of Anesthesia

Harvard Medical School

Senior Associate, Critical Care Medicine

Director, Pediatric NeuroCritical Care Program

Boston Children's Hospital

Boston, Massachusetts

KAREN M. WILSON, MD, MPH

Professor of Pediatrics

Debra and Leon Black Division Chief of General Pediatrics

Vice-Chair for Clinical and Translational Research

Kravis Children's Hospital at the Icahn School of Medicine at Mount Sinai

New York, New York

Editor Emeritus

RICHARD E. BEHRMAN, MD

Nonprofit Healthcare and Educational

Consultants to Medical Institutions

Santa Barbara, California

NELSON TEXTBOOK OF PEDIATRICS, TWENTY-FIRST EDITION ISBN: 978-0-323-52950-1

IE ISBN: 978-0-323-56890-6

Copyright 2020 Elsevier Inc.

All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Details on how to seek permission, further information about the Publisher's permissions policies, and our arrangements with organizations such as the Copyright Clearance Center and the Copyright Licensing Agency can be found at our website: www.elsevier.com/permissions . This book and the individual contributions contained in it are protected under copyright by the Publisher (other than as may be noted herein).

Previous editions copyrighted 2016, 2011, 2007, 2004, 2000, 1996, 1992, 1987, 1983, 1979, 1975, 1969, 1964, 1959

Notices

Knowledge and best practice in this field are constantly changing. As new research and experience broaden our understanding, changes in research methods, professional practices, or medical treatment may become necessary. Practitioners and researchers must always rely on their own experience and knowledge in evaluating and using any information, methods, compounds, or experiments described herein. In using such information or methods they should be mindful of their own safety and the safety of others, including parties for whom they have a professional responsibility. With respect to any drug or pharmaceutical products identified, readers are advised to check the most current information provided (i) on procedures featured or (ii) by the manufacturer of each product to be administered, to verify the recommended dose or formula, the method and duration of administration, and contraindications. It is the responsibility of practitioners, relying on their own experience and knowledge of their patients, to make diagnoses, to determine dosages and the best treatment for each individual patient, and to take all appropriate safety precautions. To the fullest extent of the law, neither the Publisher nor the authors, contributors, or editors, assume any liability for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions, or ideas contained in the material herein. The Publisher

Library of Congress Control Number: 2018952009

Senior Content Strategist: Sarah Barth

Senior Content Development Specialist: Jennifer Shreiner

Publishing Services Manager: Catherine Jackson

Senior Project Manager: John Casey

Senior Book Designer: Renee Duenow

Printed in Canada

9 8 7 6 5 4 3 2 1

1600 John F. Kennedy Blvd.

Ste. 1600

Philadelphia, PA 19103-2899

To the Child's Physician who through their expressed confidence in past editions of this book have provided the stimulus for this revision. May we continue to be a resource of helpful information for clinicians who care for all of our children.

R.M. Kliegman

Nadia Y. Abidi MD

Resident Physician
Department of Dermatology
University of Missouri School of Medicine
Columbia, Missouri

Mark J. Abzug MD

Professor of Pediatrics
Vice Chair for Academic Affairs
University of Colorado School of Medicine
Section of Pediatric Infectious Diseases
Children's Hospital Colorado
Aurora, Colorado

David R. Adams MD, PhD

Associate Investigator, Undiagnosed Diseases Program

Senior Staff Clinician
National Human Genome Research Institute
National Institutes of Health
Bethesda, Maryland

Nicholas S. Adams MD

Plastic Surgery Resident
Spectrum Health Hospitals
Michigan State University
Grand Rapids, Michigan

Stewart L. Adelson MD

Assistant Clinical Professor
Department of Psychiatry

Columbia University College of Physicians and Surgeons
Adjunct Clinical Assistant Professor
Weill Cornell Medical College of Cornell University
New York, New York

Shawn K. Ahlfeld MD

Assistant Professor of Pediatrics
University of Cincinnati College of Medicine

Attending Neonatologist, Perinatal Institute
Cincinnati Children's Hospital Medical Center
Cincinnati, Ohio

Osman Z. Ahmad MD

Fellow in Pediatric Gastroenterology
University of Alabama at Birmingham School of Medicine
Birmingham, Alabama

John J. Aiken MD, FACS, FAAP

Professor of Surgery
Division of Pediatric General and Thoracic Surgery
Medical College of Wisconsin
The Children's Hospital of Wisconsin
Milwaukee, Wisconsin

Cezmi A. Akdis MD

Professor of Immunology
Swiss Institute of Allergy and Asthma Research
Christine Khne Center for Allergy Research and Education
Davos, Switzerland;

Medical Faculty, University of Zurich
Zurich, Switzerland

Evaline A. Alessandrini MD, MSCE

Professor of Clinical Pediatrics
University of Cincinnati College of Medicine
Division of Emergency Medicine

Director, Quality Scholars Program in Health Care Transformation
Cincinnati Children's Hospital Medical Center
Cincinnati, Ohio

Michael A. Alexander MD

Professor of Pediatrics and Rehabilitation Medicine
Thomas Jefferson Medical College
Philadelphia, Pennsylvania;

Emeritus Medical Staff
Nemours Alfred I. duPont Hospital for Children