Diagnosing and Treating Common Problems in Paediatrics

The Essential Evidence-Based Study Guide

Michael Oneill, Michelle Mary McEvoy, Alf Nicholson

• Publisher: CRC Press
• Year: 2017
• ISBN:
  9781315343693
• Edition: 1
• Topic: Medicine
• Subtopic: Pediatric Medicine

This remarkable new guide is the first hybrid text of its kind that adopts the traditional method of medical education and fuses it with an evidence-based approach. It covers, in great detail, all of the common conditions seen in primary and secondary paediatrics.Skilfully designed for easy revision and reference, each chapter is devoted to a symptom, commencing with the objectives and essential relevant background material followed by history and examination. In the management section specific questions are posed and evidence based responses are offered, ensuring both patients and their parents are satisfied. Uniquely, in the majority of cases, evidence from randomized controlled trials is given.To facilitate comprehension, revision and examination preparation, chapter includes a series of multiple choice questions and meticulous answers. It also includes an invaluable clinical slide and X-ray collection outlining key radiological features of many of the clinical conditions described to further aid understanding, recognition and diagnosis.Diagnosing and Treating Common Problems in Paediatrics is a highly comprehensive primer of how to learn and evaluate knowledge and then translate that knowledge into practice. It provides paediatric consultants and students with the confidence, professionalism and unique communication skill required to work effectively with both children and parents, ensuring successful treatment and outcomes.

Chapter One

Evidence-Based Medicine:
The Basics

This chapter will answer five questions on evidence-based medicine (EBM).

Question 1: What is the Definition of Evidence-Based Medicine?

EBM is the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients. This is the definition offered by Dr David Sackett (one of the pioneers of EBM) in 1996.¹ The patient is at the centre of this quest and the doctor’s task is to provide the information to facilitate the patient’s choice.

Question 2: What is the Origin of Evidence-Based Medicine?

The development of EBM has been a process. In the 1940s controlled clinical trials were commencing, but it wasn’t until the 1970s that Professor Archie Cochrane enunciated the principles that were later to form the basis of EBM. However, developing these concepts into a practical methodology and employing them in everyday clinical practice was initially achieved by Dr David Eddy (Duke University, North Carolina) and by Dr David Sackett and Dr Gordon Guyatt at McMaster University in Hamilton, Ontario, in the late 1980s. The essentials of EBM were incorporated into the book Users’ Guides to the Medical Literature: A Manual for Evidence-Based Clinical Practice, written by the Evidence-Based Medicine Working Group and edited by Gordon Guyatt and Drummond Rennie.²

Question 3: How Do I Begin to Practise Evidence-Based Medicine?

Evidence-based practice involves asking and answering questions, e.g. will a 3-year-old with no risk factors for asthma but with acute viral wheeze benefit from oral steroids or will a 4-year-old with acute otitis media benefit from antibiotic treatment? These questions have similar elements: first, the population (children with otitis media or asthma); second, there is an intervention (antibiotic or steroid therapy); third, a comparison (analgesia or bronchodilator treatment); and fourth, a clinical outcome (avoidance of antibiotic treatment and steroid treatment with associated side effects). This gives rise to the structured clinical question PICO format, where P refers to patient or problem, I refers to the intervention, C refers to the comparison and O refers to the outcome.

Question 4: Where Do I Get Information on Evidence-Based Medicine?

The following websites provide evidence-based summaries:

• The Cochrane Library – www.thecochranelibrary.com
• Trip – www.tripdatabase.com
• PubMed Clinical Queries – www.ncbi.nlm.nih.gov/pubmed/clinical
• DynaMed – https://dynamed.ebscohost.com
• Embase – www.embase.com
• UpToDate – www.uptodate.com

Specific sites that publish evidence-based guidelines include the National Institute for Health and Care Excellence and the Scottish Intercollegiate Guidelines Network.

Many people search PubMed and get perhaps thousands of citations per search. This is not useful, as no one has time to trawl through each citation and review the abstract for relevance; it is more appropriate to have 10 relevant citations. Prior to using PubMed it is essential to be familiar with search strategies. The online tutorials provided by PubMed ultimately save time. If you are unable to answer the following questions you need to do these tutorials: What is the PMID number? What are clinical queries? What does MeSH mean? Where do the words ‘related citations’ appear on the screen?

Question 5: What Do I Need to Know About Randomised Controlled Trials in Relation to Evidence-Based Medicine?

Randomised controlled trials (RCTs) are being used increasingly in medicine to define therapy effectiveness. The core concept of RCTs is that study groups are very similar, with the only variable within the study being the intervention, and therefore the resulting outcome is attributed to the intervention. The word ‘randomised’ refers to distributing measured characteristics, e.g. age or disease severity, equally in each group. An advantage of the randomisation process is that unmeasured variables are likely to be equally distributed among the groups. A useful way to analyse RCTs is outlined as follows.

Aim of study

The aim should state why the study is being undertaken. For example, in adolescents with acute migraine headaches, how effective in the treatment of pain is strategy A as compared with strategy B? The question asked is explicit and clearly defined.

Methods

• Participants. The eligibility of the study population needs to be understood. What are the criteria for entry into the study and what features result in exclusion from the study? The reader should be aware of the recruitment process – were participants recruited from hospital clinics or general practitioners’ practices or were advertisements used in the paper? The description of the population allows the physician to relate the studied population to his or her own practice. Recruitment of patients from a tertiary care centre asthma clinic is likely to result in patients with severe disease being recruited into the study and the results may not be applicable to a doctor working in a primary care setting.
• Intervention. What is the intervention in the study? This needs to be stated clearly, e.g. patients will be randomised to receive treatment A or placebo.
• Outcomes. What are the primary outcomes? Primary outcomes need to be relevant and measurable, e.g. in an adolescent with migraine, as defined by the International Headache Society criteria for migraine, what is the impact of treatment X versus treatment Y, on the presence of pain at 2 hours? The primary outcome is defined (pain-free at 2 hours) and a method for measurement (e.g. visual analogue scale) must be outlined. Secondary outcome must be stated prior to the study commencing.
• Sample size and its calculation. In determining the sample size the following need to be evaluated: (a) an estimate of an important outcome difference that would be clinically relevant, (b) the alpha level (type I error), (c) the statistical power (type II error) and (d) for continuous outcomes, the standard deviation of the mean. The size effect is inversely related to the sample size. Traditionally the alpha level is set at P < 0.05, i.e. a 1 in 20 chance that the results are incorrect. Type II errors indicate there is no difference, when in fact there is.
• Randomisation. Once the group of eligible participants has been determined, there is a need to separate them into two groups, with the proviso that each participant has an equal chance of being assigned into either group. This is the basis of correct randomisation. In effect, when this is done correctly important characteristics of the patients will be equally divided into the two groups. The best way to randomise is to utilise a central computer-based randomisation. This has the added advantage of being remote from the investigators and patients, which makes it difficult to predict which patient will be assigned to the intervention or the control group. Utilising sealed, opaque envelopes sounds like a good idea, but if there is a way of influencing the group to which the patient is assigned, then this randomisation process is flawed and should not be used. Some older studies used date of birth (odd versus even days) or days of the week on which the participant attended, to define the group to which he or she is assigned; this is not randomisation, as participants do not have an equal chance of being assigned to either group. The process is referred to as ‘pseudo-randomisation’. This concept of ‘not knowing’ or being unable to predict the group to which the next patient will be assigned is called allocation concealment and is employed to reduce bias.
• Blinding refers to withholding information that relates to the intervention from persons who may be influenced by this knowledge, especially if the outcomes are subjective. The term ‘double-blind’ indicates that both patients and investigators are unaware of the treatment allocation – this reduces bias. Double-blinding is not possible if a surgical intervention is being evaluated against a medical treatment. If the primary outcome is objective, e.g. death, then blinding is not a concern, because the measurement of the outcome cannot be influenced. On the contrary, where the measurement can be influenced the blinding of the assessor is crucial. In reviewing an RCT, it is essential to know who the assessor of the outcome is, and that they are unaware of which particpant received which intervention. This needs to be ensured (if possible).
• Statistical methods refer to the analysis of the data to determine magnitude of the treatment effect.

Results

• The presence of a flow diagram is very useful. This diagram indicates (a) the number of patients who were eligible, (b) those who participated, (c) those who received the intended treatment and (d) those who were analysed in respect to the primary outcome. When reviewing the flow diagram, certain observations should be made: (a) of those eligible, how many agreed to participate and what were explanations offered for non-participation? (b) of those who were randomised to the intended treatment, what percentage was not analysed in determining the results of the study?
• Baseline data. If the randomisation was undertaken correctly, then the groups should be similar for baseline characteristics, as each person’s assigned group was determine by chance. If baseline characteristics are similar between groups then the reader is reassured that the randomisation has been done correctly.
• Numbers analysed. The numbers analysed are important, because if the difference between those who commenced the intervention and those for whom data are available is significantly different, the results are not valid. If 100 patients are assigned to the intervention arm, loss of five patients will not have a great bearing on the results; however, if the number is 20, then the reader should be concerned and look for an explanation of same (this is the basis of the ‘5 and 20’ rule: 5 or less is acceptable, 20 or greater is very concerning). The concept of intention-to-treat analysis is that patients are analysed in the group to which they were assigned, and if data are not available then an assumption is made that they have experienced a poor outcome. For example, in a study of a medical and surgical intervention, 100 patients are assigned to each group. In the medical group all 100 patients receive the intervention and 40 get better. However, in the surgical group of the 100 patients assigned, only 70 have the procedure and 35 get better. Which treatment should I recommend? The percentage success of the medical treatment is 40/100 (40%) and the surgical treatment is 35/70 (50%). The surgical treatment offers the better outcome, but the 30 patients who did not receive the surgical treatment must be taken into account and analysed in the group to which they were assigned; as no data are available we must assume a negative outcome and therefore the surgi...

Table of contents

• Cover Page
• Title Page
• Copyright Page
• Table of Contents
• Foreword
• Preface
• About the Authors
• How to Use the CD for Learning
• Acknowledgements
• 1 Evidence-Based Medicine: The Basics
• 2 Communication
• 3 First Response
• 4 The Child with a Fever
• 5 The Child with Recurrent Infections
• 6 The Afebrile Infant with Excessive Crying
• 7 Common Problems with Infant Feeding
• 8 Food Allergy in Children
• 9 The Child With Vomiting
• 10 The Child With Abdominal Pain
• 11 The Child With Diarrhoea
• 12 Constipation in Children
• 13 Failure to Thrive (Inclusive of Eating Disorders)
• 14 Nocturnal Enuresis
• 15 DAYTIME WETTING
• 16 Cough In Children
• 17 The Child With Wheeze
• 18 The Child With Suspected Congenital Heart Disease
• 19 Recurrent Headaches In Children
• 20 Seizures
• 21 Sleep Problems In Children
• 22 The Child With Developmental Delay
• 23 The Child With Down’s Syndrome
• 24 The Child With A Limp
• 25 The Pale Child
• 26 Short Stature
• 27 The Child With A Pubertal Development Disorder
• 28 The Child With Diabetes Mellitus
• 29 Childhood and Adolescent Obesity
• 30 The Child With an Acute Rash
• 31 The Child with a Chronic Rash
• 32 Attention Deficit Hyperactivity Disorder in Children
• Index