Step 3 Board-Ready USMLE Junkies 2nd Edition: The Must-Have USMLE Step 3 Review Companion

© 2022 by USMLE JUNKIES & Dr. Lala, MD, MBA.

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Second printing

This publication is a second edition, and it has been modified by implementing new and relevant information, photos, and tables. It contains educational information in the field of medicine. Medicine is always changing especially when new research and clinical developments become available for education. The author and publisher have checked with sources to make sure information and educational material contained in this book are up-to-date to meet the standards accepted at the time of publication. Due to the possibility of human errors and updates in medicine and research and sciences, neither the author, publisher, nor contributors herein, warrants or guarantees the information contained in this book is in every aspect accurate or complete. They disclaim all warranties including without limitation any implied warranty of fitness for a particular purpose and responsibility for any errors or omissions, or for the results found in this book. For example, any medication or drug therapy mentioned herein is not to be used as guide when administering a patient, but readers are encouraged to check product information sheet and confirm with other sources.

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Dedication

To doctors-in-training who realize education is essential to proper management of their patients.

To patients who make the pursuit of medicine worth everything and more.

Acknowledgments

We would like to extend more thanks to the residents for their feedback and recommendations throughout the development of Step 3 Board-Ready USMLE Junkies, 1st and 2nd edition.

Continuous thanks to the editor for an outstanding work and making our job easier.

Introduction

This book series was started to find a systematic approach to reviewing for Step 3. Because of the feedback from the first edition, we were able to properly edit and apply recommendations to the second edition as provided by users. One of the requests was to keep the feature where you are given a quick glance at the subject matter while relating it to other important areas in medicine. It is more like a stepwise approach to any subject matter. Again, there isn’t any other Step 3 review book that uses a stepwise, quick, and high-yield approach in this manner. So we are happy to see that the readers appreciate this and request for it to remain.

Before you take the Step 3 examination, you would have either taken Step 1 and 2, or you have knowledge of the examination materials already. Step 1 or Step 2 is not any easier than Step 3. However, Step 3 is probably the most important as a practicing physician because it deals with questions that are relevant to patient management both inpatient and out-patient settings.

While it is recommended you take Step 3 during or after your residency, you may still take it before residency if you’re well prepared for it. Step 3 Board-Ready USMLE Junkies will help you achieve this success. Depending on your familiarity with the Step 3 materials, it is important to also use a comprehensive textbook along with this book, Step 3 Board-Ready USMLE Junkies as a supplement.

The topics found on Step 3 cover all subspecialties. The questions are multiple choices, usually long, and mostly clinically oriented. As of 2021, there were changes made to the USMLE exams whereby FSMB and NBME will only allow a retake of the Step exams for a maximum of four times. As far as the format of Step 3 examination, it is still a 2-day examination; 8-hours each. The first day is all multiple-choice questions concentrating on epidemiology or population health, interpretation of the medical literature, medical ethics, systems-based practice or patient safety, and assessing knowledge of diagnosis and management. The newer formats include scientific abstract and pharmaceutical advertisements. The second day is both multiple-choice questions and clinical-case scenarios, a computer-based Case Simulations (CCS), where you examine and manage a patient in both emergency and office settings. It is important that you practice the clinical-case scenarios before attempting the Step 3 because they are crucial to the passing of this exam. The practice relies on the familiarity with the use of the CCS software. After completion of the 2-day, 8-hours long examination, you will receive a single score and a single pass or fail outcome.

Computer-based Case Simulations (CCS)

Practicing your case simulations is especially important to pass the Step 3. Make sure you are familiar with the software that comes with your registration package or can be found on USMLE website. The exam is given on Day 2 of the Step examination.

Here are some tips to help with making the computer-based case simulations easier.

WHEN TO ADMIT TO ICU

Mnemonics: DR D.E.M.S = DKA → Respiratory failure → Delirium → Electrolytes imbalance → MI (post) → Shock.

INITIAL WORKUP TO CONSIDER IN ER

Mnemonics: V.O.I.C.E.S = Vitals (including cardiac & BP monitoring) → Oxygen (& pulse Oximetry and/or ABG) → IVF (hold off initially in CHF; & IV access) → Chest x-ray → ECG (and Echo) → Symptoms (treat presenting symptoms).

TIPS DURING EXAMINATION

When you just do not know the answer:

1. Choose the most common cause.

2. Remember answers that seem to be right most of the time such as: corticosteroids/steroids (prednisone), indomethacin, or ACEIs. These answers are usually there because they may be the answers. So, if you do not know, they are ‘safer’ options.

3. Look out for ‘obvious’ or the ‘simpliest’ answer such as: ‘observe’, ‘self-limiting’, follow-up with serial x-rays, NPO/IVFs/Antibiotics combination, dietary history, or medication list. These answers are there and can be easily overlooked; they are what we call the ‘DUH moment!’

4. Be confident. Sometimes, you may need to work from your answer choices back up to the questions (instead of the questions to the answer choices). You should look at the answer choices to see in what scenario they would have been the answers. So, you are using the ‘unlikely’ answer choices that you are sure are NOT possible to arrive at the most likely or the ‘got-to-be’ answer choice.

Chapter 1 Cardiology

Chest Pain and Myocardial Infarct

1. While all emergencies are considered emergency in the ER, chest pain is probably the one that requires immediate evaluation. It is a serious symptom that should be further evaluated. It calls for determining whether or not the chest pain relates to the heart.

2. It is important to remember that atherosclerotic occlusion of the coronary arteries primary cause of ischemic heart disease.

3. When you have a patient with epigastric pain, consider acute coronary syndrome = unstable angina in your diagnosis because it is the most common cause of epigastric pain.

4. Stable angina => a patient has chest pain or shortness of breath during exertion which is relieved with rest or nitroglycerin.

5. Unstable angina => a patient has chest pain or shortness of breath during rest which is not relieved with rest or nitroglycerin.

6. Myocardial Infarction => chest pains that persist for 15-30 minutes and may or may not radiate to the shoulder, arm, or jaw. Look for an ECG which shows flipped or flattened T waves, ST-segment elevation and occasionally, Q waves.

7. Don’t make the mistake--some myocardial infarctions are asymptomatic and silent; therefore, they may present as atypical in some young and even elderly patients!

Lab Tests/Diagnosis:

1. Chest pain => always CHECK ECG first + then cardiac enzymes (troponin) + Chest x-ray + stress test.

2. Cardiac enzymes => creatine kinase (CK-MB) (every 8 hours X 3 times), troponin (may hang around for days), lactate dehydrogenase (LDH) (rises after 24 hours-late presentation).

3. Chest x-ray => may show cardiomegaly, pulmonary congestion, or congestive heart failure.

4. Echocardiography => if you suspect valvular disease, congestive heart failure, or presence of bilateral pulmonary rales.

5. Stress test => to evaluate the location of the ischemia as a result of stress.

6. THINK: C. E. C. E => Cardiac enzymes + ECG + Chest x-ray + Echocardiography.

Treatment:

1. Oxygen, Nitroglycerin, Morphine (for pain if pulmonary edema is present) Aspirin, Plavix (clopidogrel), Heparin, ACEI, Beta blocker, Statin => THINK: ON MAP HABS or MONA BASH P.

2. Cardiac catheterization is used to locate occlusions and determine the severity. Occlusion may be treated with angioplasty and stent placement. Angioplasty must be performed within 90 minutes of arrival at the emergency room for STEMI. If the angioplasty cannot be performed within 90 minutes of ER arrival, order thrombolytics (Clopidogrel or Prasugrel) STAT (give that within 30 minutes of arrival in ER)! Remember to ask for cardiology consultation!

3. Cardiac rehabilitation in the form of supervised exercise is recommended 4-6 weeks post-MI.

4. Order a cardiac stress test after 24-48 hours in a patient with chest pains (non-acute) in the following conditions: no risk factors, when the result is equivocal or the presence of coronary artery disease is uncertain with normal cardiac enzymes, and normal ECG.

5. A patient complaining of fear of sudden death during sexual activity post-MI may be due to anxiety. Remember also that anxiety is a more common cause of erectile dysfunction in post-MI patients than beta-blockers.

6. When a less common cause of erectile dysfunction in post-MI patients is due to beta blocker medications → just hold the drug and reevaluate!

Post Myocardial Infarction Complications:

1. Ventricular fibrillation, ventricular tachycardia, sinus bradycardia, heart block, cardiogenic shock, papillary muscle rupture, ventricular septal defect, Dressler’s syndrome, and fibrinous pericarditis.

2. If acute pulmonary edema exists 2-5 days after an MI => it may be due to papillary muscle rupture and mitral regurgitation. Obtain a transthoracic echocardiography (TTE) or a transesophageal echocardiography (TEE).

Stress Test & Cath Lab for PCI Stent

1. Stress test => may be used to assess pretest probability in patients with history of chest pains and risk factors for coronary artery disease.

2. It is also used to assess the functional capacity in patients with known coronary artery diseases.

3. Remember that in a patient with chest pain and coronary artery disease risk factors, always obtain EKG and cardiac enzymes to rule out MI before performing a stress test.

4. Please do NOT obtain a stress test in patients with: acute aortic dissection, aortic stenosis, third degree heart block, acute coronary syndrome, and decompensated heart failure!

Types of Stress Test:

1. Exercise Stress Test:

• Patient walks on treadmill, and the response to stress is evaluated on ECG.

• Indicated for patients who can walk or exercise without difficulty.

• Clinical symptoms to observe are chest pains or shortness of breaths.

• ECG changes may include ST depressions or other arrhythmias.

• Specificity is low for patients with resting ECG changes.

• Adding nuclear component to perfusion study increases sensitivity.

2. Adenosine Stress Test/Persantine (Dipyrimadole) Test:

• Vasodilation test helps to dilate arteries with lesions.

• Indicated for patients who cannot walk or exercise with difficulty due to → peripheral arterial disease, osteoarthritis, or obesity.

• Also indicated for patients → already on beta blocker → with left bundle branch block (LBBB) → or premature ventricular contractions (PVCs).

3. Dobutamine Stress Test (Echocardiography):

• Used to determine the abnormal ventricular wall and viability. Ischemic wall is hypokinetic.

• Indicated for patients with moderate to severe COPD or asthma, third-degree heart block, or where persantine is contraindicated.

Cath Lab for PCI Stent: procedure used to diagnose acute coronary syndrome thrombosis (STEMI/NSTEM) with insertion of wire to the coronary vessels to access for obstruction. If 1-2 vessels are obstructed, it will require stent, and if 3 or more or with bigger vessels are obstructed, it will require CABG. It requires dual-antiplatelet therapy → ASA 81, Clopidogel 75.

TPA – given if patient is in rural hospital area and PCI placement time is more than 60 mins!

From patient’s arrival to the hospital door to PCI balloon placement time should be within 90 minutes for core measure purpose.

Valvular Heart Disease Aortic Stenosis

• Chest pain + syncope during exertion + exercise intolerance + shortness of breath with heart failure symptoms. Mostly in old men with atherosclerosis.

• Crescendo-decrescendo systolic murmur.

• ‘Slow’ carotid upstroke => elderly with AS vs ‘brisk’ carotid upstroke => hypertrophic obstructive cardiomyopathy (HOCM) and usually seen in young athletes.

Diagnosis: ECG, Chest x-ray, TTE (best initial), TEE (more accurate than TTE), and left heart catheterization (most accurate; measures pressure gradient; normal < 30 mmHg).

Treatment of symptomatic AS => aortic valve replacement.

Use valvuloplasty in adult patients with symptomatic AS but present with comorbid conditions.

• Avoid nitrates (overdiuresis) and ACEIs (vasodilator) in symptomatic patients. Follow up every 6 months to 1 year for physical assessment and evaluation with serial echocardiograms for severe and symptomatic AS.

Aortic Regurgitation

• Watch for patients who are asymptomatic or become symptomatic with heart failure, pulmonary edema, cardiogenic shock.

• Wide pulse pressure, diastolic decrescendo murmur heard best at the base left sternal border.

• Look in the history for => aortic dissection, infection, infarction, Marfan’s syndrome, syphilis, aortic root disease, ankylosing spondylitis, and reactive arthritis.

THINK: W.A.R → Wide pulse pressure => Aortic Regurgitation.

Diagnosis => ECG, Chest x-ray, TTE (best initial), TEE (more accurate than TTE), and left heart catheterization (most accurate; measures pressure gradient; normal < 30 mmHg).

Treatment of AR => ACEIs, ARBs, nifedipine, hydralazine, or aortic valve replacement if symptomatic or in decreased EF < 55%.

Mitral Stenosis

• Watch for young patients in their ages 20-30, mostly females, who present with hemoptysis and heart failure. Other symptoms are dysphagia, hoarseness, and AFib.

• May be caused by rheumatic fever. Also seen in immigrant and pregnant patients (due to increased plasma volume).

• Diastolic rumble after an opening snap, heard at 5th intercoastal space, midclavicular line, at apex. Patient presents with Atrial strain + CHF symptoms.

Diagnosis => ECG, Chest x-ray, TTE (best initial), TEE (more accurate than TTE), and left heart catheterization (most accurate; measures pressure gradient; normal < 30 mmHg).

Treatment of MS => Diuretic (best initial); valve replacement and balloon valvuloplasty (most effective). Same treatment in pregnancy.

THINK => Ms. HCTZ (Ms. Hydrochlorothiazide for treatment)

Mitral Regurgitation

• Mitral regurgitation may be asymptomatic initially, and it can later present with symptoms of heart failure (dyspnea on exertion). Also, look for history of infection and infarction,

• Holosystolic murmur at apex and radiating to axilla.

• Presents with right atrial stretch/dilatation + CHF + AFib

Diagnosis => ECG, Chest x-ray, TTE (best initial), TEE (most accurate).

Treatment of MR => ACEIs, ARBs, or nifedine (best initial); valve replacement or repair (best diagnostic and if EF < 60%).

THINK => Mr. Nifedipine (for treatment)

• Risk: atrial fibrillation.

Mitral Valve Prolapse

• Mitral valve prolapse is usually asymptomatic. It may present with palpitations.

• MVP is associated with panic attacks or panic disorder.

• Endocarditis prophylaxis is not required for MVP.

THINK: P in Prolapse => Panic attacks → Palpitations.

Infective Endocarditis

1. Symptoms => acute (infectious): fever, rigors, heart failure, and neurologic problems with systemic emboli; subacute: weeks to months of fever, malaise, weight loss; noninfectious: asymptomatic and heart failure.

2. Physical exam findings => new murmur, tenderness over the spine and focal neurologic deficits (present with septic emboli); infectious: painful nodules (Osler’s nodes) on fingers and toes, Janeway lesions on skin, and retinal exudates (Roth’s spots).

3. High risk patients => they usually have history of prosthetic heart valves, previous infective endocarditis, cyanotic congenital heart disease, surgically repaired pulmonary shunts, or are injection drug abusers.

4. High risk procedures needing prophylaxis in high risk patients => dental procedures such as tooth extraction, scaling and cleaning, gingival manipulation, and respiratory procedure such as rigid