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BROCHERT’S CRUSH STEP2 This page intentionally left blank THE ULTIMATE USMLE STEP 2 REVIEW FOURTH EDITION Theodore X. O'Connell, MD Program Director, Family Medicine Residency Program Kaiser Permanente Woodland Hills, California Assistant Clinical Professor, Department of Family Medicine David Geffen School of Medicine at UCLA, Los Angeles, California Partner Physician, Southern California Permanente Medical Group Woodland Hills, California Mayur K. Movalia, MD Hematopathologist Dahl-Chase Pathology Associates Bangor, Maine BROCHERT’S CRUSH STEP2 www.cambodiamed.blogspot.com | Best Medical Books | Chy Yong 1600 John F. Kennedy Blvd. Ste 1800 Philadelphia, PA 19103-2899 Brochert's Crush Step 2: The Ultimate USMLE Step 2 Review ISBN: 9781455703111 Copyright © 2013 Saunders, an imprint of 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 2007, 2003 Library of Congress Cataloging-in-Publication Data O'Connell, Theodore X. Brochert's crush step 2 : the ultimate USMLE step 2 review / Theodore X. O'Connell, Mayur Movalia. – Ed. 4. p. ; cm. Brochert's crush step two Crush step 2 Rev. ed. of: Crush step 2 / Adam Brochert. 3rd ed. c2007. Includes bibliographical references and index. ISBN 978-1-4557-0311-1 (pbk. : alk. paper) I. Movalia, Mayur. II. Brochert, Adam, 1971- Crush step 2. III. Title. IV. Title: Brochert's crush step two. V. Title: Crush step 2. [DNLM: 1. Clinical Medicine–Examination Questions. WB 18.2] 616.0076–dc23 2011043807 Acquisitions Editor: James Merritt Developmental Editor: Christine Abshire Publishing Services Manager: Peggy Fagen Project Manager: Deepthi Unni Design Direction: Steven Stave Printed in the United States of America Last digit is the print number: 9 8 7 6 5 4 3 2 1 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. v STUDENT REVIEW BOARD Each of the following student reviewers scored within the 99th percentile on the USMLE Step 2. The authors and publisher express sincere thanks to these students who provided many useful comments and helpful suggestions for improving the text and questions that appear in this product. Keila Ching, MD Class of 2010 David Geffen School of Medicine at UCLA Los Angeles, California Resident Internal Medicine University of Hawaii Honolulu, Hawaii Nzinga Graham, MD Resident Physician Family Medicine Kaiser Permanente Woodland Hills, California Casey Grover, MD Resident Physician Stanford/Kaiser Emergency Medicine Residency Stanford, California Christopher Dinh Nguyen, MD Resident Physician, PGY1 Internal Medicine UCLA School of Medicine Los Angeles, California Joy Sarkar, MD Resident Department of General Surgery Tripler Army Medical Center Honolulu, Hawaii Lobna Shahatto, MD Class of 2010 David Geffen School of Medicine at UCLA Los Angeles, California Resident Internal Medicine Loma Linda University Loma Linda, California Dina Wallin, MD Resident Department of Emergency Medicine UCSF/SFGH San Francisco, California Christine J. Yoon, MD Class of 2010 David Geffen School of Medicine at UCLA Los Angeles, California Resident Emergency Medicine Harbor-UCLA Medical Center Torrance, California This page intentionally left blank vii CONTENTS Introduction ix Using the QR Codes xi 1 Cardiovascular Medicine 1 2 Dermatology 12 3 Ear, Nose, and Throat 24 4 Emergency Medicine 30 5 Endocrinology 34 6 Ethics and Patient Encounters 41 7 Gastroenterology 44 8 General Surgery 57 9 Genetics 71 10 Geriatrics 76 11 Gynecology 78 12 Hematology 89 13 Immunology 98 14 Infectious Disease 103 15 Internal Medicine 114 16 Laboratory Medicine 136 17 Nephrology 138 18 Neurology 143 19 Neurosurgery 156 20 Obstetrics 163 21 Oncology 182 22 Ophthalmology 197 23 Orthopedic Surgery 205 viii Contents 24 Pediatrics 211 25 Pharmacology 231 26 Preventive Medicine, Epidemiology, and Biostatistics 236 27 Psychiatry 244 28 Pulmonology 255 29 Radiology 261 30 Rheumatology 264 31 Urology 271 32 Vascular Surgery 278 33 Photos, Images, and Multimedia 283 34 Signs, Symptoms, and Syndromes 312 Appendix: Abbreviations 315 Answers 321 ix INTRODUCTION This fourth edition of Crush Step 2 attempts to incorporate the many changes that have occurred in medicine and the exam since 2007, as well as suggestions from readers based on material they encoun- tered on their exams. For this edition, we have created a student review board composed of recent students who each scored in the 99th percentile on Step 2. Their input and suggestions have been invaluable in helping this book reflect the content and structure of the recent USMLE Step 2 exams. Though the format of the exam is constantly changing, many of the basic concepts you need to know to be a successful house officer have not changed in decades. If you understand the concepts in this book, you should do much better than pass: you should Crush Step 2! Though Step 2 is the same level of difficulty as Step 1, the focus is more clinical and the questions are more relevant to the everyday practice of medicine. Knowing how to recognize, diagnose, manage, and treat common conditions is stressed. The exam tests not just theory but practice—in other words, what you should do next. Treatable emergency conditions are also tested, because you will soon be asked to take care of patients in the middle of the night, some of whom may require heroic measures if they are to survive until morning rounds. Some information from Step 1 is still relevant and high yield for Step 2. Epidemiology and biostatistics, pharmacology, and microbiology are all tested with a slightly more clinical slant. Cardiac physiology and pathophysiology and behavioral science are also retested and are high yield. Overall, though, Step 2 has a different focus, and that focus is clinical. If a patient presented with chest pain, what would you do? What kinds of questions would you ask him or her? Which tests would you order? How would you select medications or treatments? Here are some general tips to keep you focused while studying for and taking the test: 1. Always get more history when it is an option, unless the patient is unstable and you think imme- diate action is needed. 2. Know the cutoff values for the treatment of common conditions (e.g., at what numbers do you treat hypertension, diabetes, and hypercholesterolemia; below what CD4 count should you institute chemoprophylaxis in HIV patients). 3. A presentation might be normal, especially in psychiatry and pediatrics, and require no treatment! 4. Don't forget to study your subspecialties. Just because you never took an ophthalmology or dermatology rotation doesn't mean there won't be any basic questions on these topics. You don't have to be an expert, but knowing common and life-threatening diseases in the subspecialties can significantly increase your score. 5. Time management during the exam is critical. Make sure you are prepared to answer all of the questions in the allotted time. Residency programs generally only see those magic two- and three-digit scores, not the breakdown. Don't skip studying a subject because you know you aren't going into it—you might miss out on easy points. Studying for Step 2 can seem like an overwhelming task. Given the time constraints of medical students in their clinical years, most need a concise, high-yield review of the tested topics. It is our hope that Crush Step 2, fourth edition, will meet your needs in this regard. Theodore X. O'Connell, MD Mayur K. Movalia, MD This page intentionally left blank xi USING THE QR CODES The QR codes in this book correspond to USMLE-style questions and images. For fast and easy access, right from your mobile device, follow these instructions. What You Need ❍ A mobile device, such as a Smartphone or tablet, equipped with a camera and Internet access ❍ A QR code reader application (If you do not already have a reader installed on your mobile device, look for free versions in your app store.) How It Works ❍ Open the QR code reader application on your mobile device. ❍ Point the device's camera at the code and scan. ❍ Each code opens questions or images for instant viewing—no log-on is required. This page intentionally left blank 1 CARDIOVASCULAR MEDICINE CHEST PAIN, MYOCARDIAL INFARCTION, AND ACUTE CORONARY SYNDROME When a patient presents with chest pain, your job is to make sure that the cause is not life threatening, which usually means that you investigate the possibility of a myocardial infarction (MI). Findings that make MI unlikely: ❍ Wrong age: In the absence of known heart disease, a strong family history, or risk factors for coronary artery disease (CAD), a patient younger than 40 years of age is extremely unlikely to have had an MI. ❍ Risk factors: A 50-year-old marathon runner who eats well and has a high high-density lipoprotein level without other risk factors for coronary heart disease is unlikely to have had an MI. A long-term smoker with a positive family history and chronic hypertension, diabetes, and hypercholesterolemia has had an MI until you prove otherwise! ❍ Physical characteristics of pain: If the pain is reproducible by palpation, its source is the chest wall and is not an MI. Pain should not be sharp and well localized or related to certain foods. Findings that elevate suspicion of MI: ❍ EKG: After an MI, you should see flipped or flattened T waves, ST-segment elevation (depression means ischemia; elevation means injury), or Q waves in a segmental distribution (e.g., leads II, III, and aVF for an inferior infarct) as shown in Figure 1-1. ❍ Pain characteristics: Usually described as an intense pressure or crushing sensation that may be poorly localized or in the substernal region. The pain may radiate to the shoulder, arm, or jaw; it is not reproducible on palpation. The pain usually does not resolve with nitroglycerin (as it often does with angina) and generally lasts at least a half hour. ❍ Laboratory values: A patient with a possible MI should have serial determinations of troponin I or T (usually drawn every 8 hours three times before MI is ruled out). Creatine kinase (the MB isoenzyme) is now less commonly used but results also can be positive. Late patient presentation (>24 hours): Troponin I or T can be used because both are still elevated several days after an MI (CK-MB begins to decrease 24 hours after an MI and might give a false-negative test result; if the CK-MB is elevated 2–3 days after an MI, think recurrent infarction). Lactate dehydroge- nase (LDH) elevation and flip (LDH1 > LDH2) is now rarely used, and results take 24 hours to become positive. Aspartate aminotransferase is also elevated in those who have had an MI but is not used clinically. Radiography might show cardiomegaly or pulmonary congestion; brain natriuretic peptide (BNP) may be elevated; echocardiography might show ventricular wall motion abnormalities. ❍ History: Patients with MI often have a history of angina or previous chest pain, murmurs, arrhyth- mias, or risk factors for CAD. Some are taking cardiovascular medications (digoxin, furosemide, antihypertensives, cholesterol medications). ❍ Physical examination: Patients are often diaphoretic, dyspneic, tachycardic, and pale; nausea and vomiting may be present. Bilateral pulmonary rales in the absence of other pneumonia-like symptoms, distended neck veins, S3 or S4, new murmurs, hypotension, or shock should make you think along the lines of a large MI. Remember that right ventricle infarcts present with clear lung fields, increased jugular venous pressure (JVP), and decreased blood pressure. 2 CHAPTER 1 n CARdiovAsCulAR MEdiCinE Treatment for an MI involves hospital admission to the intensive care unit (ICU) or cardiac care unit with adherence to several basic principles: ❍ Early thrombolysis (generally ≤12 hours from pain onset) is appropriate if the patient meets strict criteria for use. Early thrombolysis (<4–6 hours) is preferred to try to salvage myocardium. Reperfusion therapy is defined by patient and medical center criteria and may be accomplished by thrombolysis or coronary angiography with percutaneous transluminal coronary angioplasty (PTCA). Coronary artery bypass grafting (CABG) may be required if thrombolysis is contraindicated (or in combination with it). ❍ Electrocardiographic (EKG) monitoring: If ventricular tachycardia develops, use amiodarone. A common cause of death from an acute MI is reentry arrhythmia such as ventricular fibrillation. ❍ Give O2 by nasal cannula or face mask (maintain O2 saturation >90%). ❍ Pain control with morphine (which can help with pulmonary edema if present) ❍ Nitroglycerin causes venodilation that leads to increased pooling the systemic venous circulation and decreased preload. ❍ β-Blocker (which the patient should take for life if no contraindications are present; proven to reduce the mortality rate of MI as well as the incidence of second MI) ❍ Administer aspirin (and possibly low-dose heparin or other newer antiplatelet agents) ❍ Administer clopidogrel if the patient has undergone percutaneous coronary intervention or has unstable angina or non–ST-elevation MI. ❍ Administer unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH). ❍ Heparin should be started if unstable angina is diagnosed, if the patient has a cardiac thrombus, a large area of dyskinetic ventricle, or if severe CHF is seen on EKG. The Step 2 examination will not ask about other indications, which are not as clear cut. Do not give heparin to patients with contraindications such as active bleeding. ❍ An angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) should be started within 24 hours. ACE inhibitors are also indicated for patients with CHF because they have been shown to reduce mortality in this setting. ❍ Administer an HMG-CoA reductase inhibitor (statin). Keep post-MI complications in mind. Ventricular rupture and papillary muscle rupture occur approximately 1 week after an MI. Ventricular aneurysms can occur days to months after an MI (may present with akinesis, arrhythmia, or systemic emboli). Post-MI pericarditis (Dressler syndrome) occurs a few weeks after an MI (treat with nonsteroidal antiinflammatory drugs [NSAIDs]; do not give anticoagula- tion or the patient may develop a hemorrhagic pericardial effusion). Remember that calcium channel blockers (CCBs) are contraindicated for acute coronary syndrome. Twenty-five percent of MIs are silent, meaning that they manifest without chest pain (especially in patients with diabetes who have neuropathy). Such patients present with CHF, shock, or confusion and delirium (especially elderly patients). Figure 1-1 Acute myocardial infarction localized to inferior leads (ii, iii, and avF). The elec- trocardiogram (EKG) shows sT-segment elevation with hyperacute peaked T waves and early devel- opment of significant Q waves. Reciprocal sT depression is also seen (leads i and avl). (From Seelig CB: simplified EKG Analysis. Philadelphia, Hanley & Belfus, 1992.)