Brochert's Crush Step 2: The Ultimate USMLE Step 2 Review, 4e

444 Pages·2012·11.73 MB·English

BROCHERT’S
CRUSH
STEP2

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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

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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
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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
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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

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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 derma-
tology 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 stu-
dents 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

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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.

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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 symp-
toms, 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 contraindi-
cated (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 contra-
indications 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 local-
ized 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.)