IM Essentials Text Samples

Designed for the Internal Medicine Clerkship

A Medical Knowledge Self-Assessment Program® (MKSAP®) for Students

• An abbreviated textbook organized by the traditional subspecialty topics of internal medicine • More than 250 differential diagnosis tables and treatment algorithms • Over 150 color plates, imaging studies, and electrocardiograms included

Includes FREE access to the online version of IM Essentials containing both questions and text plus flashcards! See access code inside.

text

Provides the core curricular content for the internal medicine clerkship:

Contents

1. Cardiovascular Medicine 1

Approach to Chest Pain

2

Chronic Stable Angina

3

Acute Coronary Syndrome

4

Conduction Blocks and Bradyarrhythmias

5

Supraventricular Arrhythmias

6

Ventricular Arrhythmias

7

Heart Failure

8

Valvular Heart Disease

9

Vascular Disease

2. Endocrinology and Metabolism 10 Hypothalamic and Pituitary Disorders 11 Thyroid Disease 12 Adrenal Disease 13 Diabetes Mellitus 14 Diabetic Ketoacidosis and Hyperglycemic Hyperosmolar Syndrome 15 Osteoporosis

3. Gastroenterology and Hepatology 16 Approach to Abdominal Pain 17 Dyspepsia 18 Gastroesophageal Reflux Disease 19 Peptic Ulcer Disease 20 Approach to Liver Chemistry Tests 21 Hepatitis 22 Cirrhosis 23 Diseases of the Gallbladder and Bile Ducts 24 Acute Pancreatitis 25 Approach to Diarrhea 26 Inflammatory Bowel Disease 27 Approach to Gastrointestinal Bleeding

4. General Internal Medicine 28 Diagnostic Decision Making 29 Therapeutic Decision Making 30 Health Promotion, Screening, and Prevention 31 Hypertension 32 Dyslipidemia 33 Obesity 34 Approach to Low Back Pain 35 Approach to Cough 36 Smoking Cessation 37 Depression 38 Substance Abuse 39 Disorders of Menstruation and Menopause 40 Approach to Syncope 41 Approach to Lymphadenopathy 42 Approach to Involuntary Weight Loss 43 Comprehensive Geriatric Assessment 44 Palliative Care 45 Genetics and Genetic Testing 46 Common Dermatologic Disorders

5. Hematology 47 Anemia 48 Sickle Cell Disease 49 Thrombocytopenia 50 Hematopoietic Stem Cell Disorders 51 Multiple Myeloma 52 Bleeding Disorders 53 Thrombophilia 54 Transfusion Medicine

6. Infectious Disease Medicine 55 Approach to Fever 56 Common Upper Respiratory Infections 57 Community-­‐Acquired Pneumonia 58 Tuberculosis

59 Infective Endocarditis 60 Urinary Tract Infection 61 Sexually Transmitted Diseases 62 HIV Infection 63 Osteomyelitis 64 Sepsis Syndrome 65 Health Care–Associated Infections

7. Nephrology 66 Approach to Kidney Disease 67 Fluid and Electrolyte Disorders 68 Calcium and Phosphorus Metabolism 69 Acid–Base Disorders 70 Acute Kidney Injury 71 Chronic Kidney Disease 72 Nephrolithiasis

8. Neurology 73 Headache 74 Approach to Meningitis and Encephalitis 75 Stroke and Transient Ischemic Attack 76 Altered Mental Status, Dementia, and Delirium 77 Peripheral Neuropathy 78 Approach to Selected Movement Disorders 79 Seizures and Epilepsy 80 Other Neurologic Diseases

9. Oncology 81 Lung Cancer 82 Breast Cancer 83 Colorectal Cancer 84 Cervical Cancer 85 Prostate Cancer 86 Skin Cancer 87 Lymphoid Malignancies 88 Oncologic Urgencies and Emergencies

10. Pulmonary Medicine 89 Interpretation of Pulmonary Function Tests 90 Approach to Dyspnea 91 Pleural Effusion 92 Asthma 93 Chronic Obstructive Pulmonary Disease 94 Obstructive Sleep Apnea 95 Diffuse Parenchymal Lung Diseases 96 Pulmonary Vascular Disease

11. Rheumatology 97 Approach to Joint Pain 98 Approach to Knee and Shoulder Pain 99 Osteoarthritis 100 Crystal-­‐Induced Arthritis 101 Infectious Arthritis 102 Rheumatoid Arthritis 103 Systemic Lupus Erythematosus 104 Spondyloarthritis 105 Other Rheumatologic Conditions 106 Systemic Vasculitis

Index

Color Plates

Section I Cardiovascular Medicine Chapter 1

Approach to Chest Pain

Chapter 2

Chronic Stable Angina

Chapter 3

Acute Coronary Syndrome

Chapter 4

Conduction Blocks and Bradyarrhythmias

Chapter 5

Supraventricular Arrhythmias

Chapter 6

Ventricular Arrhythmias

Chapter 7

Heart Failure

Chapter 8

Valvular Heart Disease

Chapter 9

Vascular Disease

High Value Care Recommendations • Use of antioxidant vitamins or hormone replacement therapy in postmenopausal women is not recommended for CAD risk reduction.

• Combined treatment with an ACE inhibitor and an ARB is not recommended as additional benefit of using these two medications together is not well established.

• Testing homocysteine levels should not be performed as part of routine cardiovascular risk assessment.

• Spironolactone is usually first-line therapy due to clinical experience and cost considerations; however, the more receptor-specific eplerenone may be useful in individuals developing gynecomastia with spironolactone.

• The American Heart Association and Centers for Disease Control and Prevention do not recommend routine measurement of hs-CRP, but measurement may be useful in patients with a moderate (10%-20%) 10-year risk of a first CAD event.

• Echocardiographic reassessment of ejection fraction is most useful when there is a notable change in clinical status rather than at regular or arbitrary intervals.

• Asymptomatic patients without cardiovascular risk factors should not undergo routine screening for CAD, either with electrocardiography or stress testing.

• Not all systolic murmurs are pathologic. Short, soft systolic murmurs (grade <3) that are asymptomatic often do not require further investigation.

• CT-based coronary artery calcium scoring is an evolving technology with unclear benefit in predicting cardiovascular risk relative to traditional risk-prediction tools; it should therefore not be used routinely.

• Routine serial echocardiography is not needed in asymptomatic patients with prosthetic heart valves.

• Patients with a low probability of CAD do not require stress testing, and patients with a high probability of CAD should be started immediately on medical management, with consideration of coronary angiography if there is no response to therapy or if severe disease is suspected.

• PET with CT is a complex and expensive diagnostic modality and its appropriate role in evaluating chronic stable angina remains to be established.

• Patients with an abnormal stress test who do not have factors suggestive of severe CAD may benefit from initial medical management.

• Percutaneous coronary intervention (PCI; angioplasty and stent placement) has not been shown to reduce mortality or cardiovascular events in patients with stable CAD, but it has been shown to reduce angina and to improve quality of life. PCI is most appropriately used in patients who do not respond to medical therapy.

• Routine resting ECGs are not recommended if there have been no changes in symptoms, examination findings, or medications. A repeat stress test is indicated if there is a change in symptoms but should not be performed routinely.

• Although newer oral anticoagulant medications do not require routine monitoring of their anticoagulation effect and may have several other potential advantages, they are significantly more expensive than warfarin.

• Echocardiography should not be used to screen for heart failure in asymptomatic patients without murmurs.

• Do not routinely measure BNP in patients with typical signs and symptoms of heart failure.

• Once heart failure is diagnosed, serial chest radiographs are not sensitive to small changes in pulmonary vascular congestion and are not recommended.

• For most patients, imaging studies are not needed for routine monitoring of PAD, but may be indicated if intervention is felt to be needed.

• In patients with a low likelihood of disease, D-dimer testing may be useful in excluding the diagnosis of dissection.

• Screening for carotid stenosis is not recommended in the general population.

• Carotid artery stenting is usually associated with a higher risk of stroke than surgery and is not routinely performed in patients with carotid stenosis.

• Patients with a low clinical likelihood of DVT should undergo testing with D-dimer as the combination of a low clinical probability, and negative D-dimer rules out DVT. • There is no indication for routine screening for DVT in asymptomatic patients at risk for VTE. • Newer oral anticoagulation medications tend to be very expensive and their long-term safety remains to be established.

Chapter 1

Approach to Chest Pain Eric Goren, MD

C

mortality rate of ACS may be as high as 10%. ACS refers to a spectrum of diseases, including unstable angina, Non-ST-segment elevation myocardial infarction, and ST-segment elevation myocardial infarction, based on electrocardiographic (ECG) changes and the presence of cardiac biomarkers (see Chapter 3). Patients with acute cardiac ischemia classically present with substernal pressure, tightness, or heaviness, with radiation to the jaw, shoulders, back, or arms. The pain may be accompanied by dyspnea, diaphoresis, and nausea. Up to 30% of patients, particularly those with diabetes mellitus, women, and the elderly, may present with atypical symptoms, such as dyspnea without chest pain. ACS should be particularly suspected in patients with atherosclerotic disease risk factors such as diabetes, hypertension, and hyperlipidemia.

The most powerful clinical features that increase the probability of myocardial infarction (MI) include chest pain that simultaneously radiates to both arms (positive likelihood ratio = 9.7) and an S3 (positive likelihood ratio = 3.2). Pain that increases with exertion is

hest pain is one of the most common complaints in internal medicine. The differential diagnosis of chest pain includes cardiac, pulmonary, gastrointestinal, musculoskeletal, and psychiatric causes (Table 1). In outpatients, the most common cause is musculoskeletal chest pain, although up to 12% of patients may have chest pain secondary to myocardial ischemia. A prudent approach to treating patients with acute chest pain focuses the initial evaluation on six potentially lethal conditions (the “serious six”): acute coronary syndrome, pulmonary embolism (PE), pericarditis/pericardial tamponade, pneumothorax, aortic dissection, and esophageal rupture.

Cardiac Causes Acute coronary syndrome (ACS) is an important cause of acute chest pain. Although only 15% to 30% of patients presenting to emergency departments with nontraumatic chest pain have ACS, the 28-day

Table 1. Differential Diagnosis of Chest Pain Disorder

Clinical Features/Notes

The “Serious Six” Acute coronary syndrome (see Chapter 3)

Frequent but not always exertional chest pain that is often not sharp or positional and radiates to both arms. Pain not easily reproducible. An S3 is occasionally present. ECG changes or elevated cardiac enzymes in initial workup followed by stress testing or catheterization.

Pulmonary embolism (see Chapter 96)

Pleuritic chest pain and shortness of breath in patients at risk for thromboembolism. Clinical probability determined using Well’s criteria. In low-probability patients, a normal D-dimer can exclude the diagnosis. If intermediate or high probability, ventilation-perfusion scan or spiral CT is indicated.

Pericarditis

Substernal chest discomfort that can be sharp, dull, or pressure-like in nature, often relieved with sitting forward; usually pleuritic. ECG changes may include ST-segment elevation (usually diffuse) or more specifically (but less commonly) PR-segment depression.

Pneumothorax (see Chapter 90)

Sudden onset of pleuritic chest pain and dyspnea in a smoker or COPD patient. Chest radiograph or CT scan confirms the diagnosis.

Aortic dissection (see Chapter 9)

Substernal chest pain with radiation to the back or midscapular region; often described as “tearing” or “ripping” pain. Pulse or blood pressure differential useful but uncommonly present. Chest radiograph may show a widened mediastinal silhouette, pleural effusion, or both.

Esophageal rupture

Intense retrosternal pain after vomiting; often associated with ethanol use. Pneumomediastinum on CXR can be seen.

Other Causes Aortic stenosis (see Chapter 8)

Chest pain with exertion, heart failure, syncope. Typical systolic murmur at the base of the heart radiating to the neck.

Panic attack

May be indistinguishable from angina. Often diagnosed after a negative evaluation for ischemic heart disease. Often associated with palpitations, sweating, and anxiety.

Musculoskeletal pain

Typically more reproducible chest pain. Includes muscle strain, costochondritis, and fracture. Should be a diagnosis of exclusion.

Esophagitis (see Chapter 18)

Burning-type chest discomfort usually precipitated by meals and not related to exertion. It is often worse upon lying down and improved with sitting.

COPD = chronic obstructive pulmonary disease; CT = computed tomography; CXR = chest x-ray; ECG = electrocardiographic; MI = myocardial infarction; VTE = venous thromboembolism.

3

4 • Cardiovascular Medicine

also suggestive of ACS. Features that make an ischemic cause less likely include a normal ECG result (negative likelihood ratio = 0.10.3), chest pain that is positional (negative likelihood ratio = 0.3), chest pain reproduced by palpation (negative likelihood ratio = 0.20.4), or chest pain that is sharp or stabbing (negative likelihood ratio = 0.3). Patients suspected of having ACS are hospitalized and evaluated with serial ECGs and cardiac biomarkers. Low-risk patients without evidence of MI are evaluated with exercise or pharmacologic stress testing, as indicated. Higher-risk patients or those with STsegment elevations undergo urgent cardiac catheterization.

Cocaine use can cause chest pain and ST-segment changes due to vasospasm, even in patients without significant occlusive coronary artery disease, and may result in myocardial injury.

Pericarditis is characterized by sudden onset of sharp, stabbing, substernal chest pain with radiation along the trapezius ridge. Often, the pain is worse with inspiration and lying flat and is alleviated with sitting and leaning forward. A pericardial friction rub is present in 85% to 100% of cases at some time during the course of pericarditis.

Given the ephemeral nature of the friction rub, its absence does not rule out pericarditis. The classic rub consists of three components: occurring during atrial systole, ventricular systole, and ventricular diastole. A confirmatory ECG reading will show diffuse ST-segment elevation and P-R segment depression, findings that are specific but not sensitive (Figure 1). An echocardiogram may be helpful if there is suspicion of significant pericardial effusion or pericardial tamponade. Acute pericarditis secondary to infection (viral or bacterial) may be preceded or accompanied by symptoms of an upper respiratory tract infection and fever. In patients with acute pericarditis, hospitalization is prompted by an associated MI, pyogenic infection, or tamponade. Outpatient management is appropriate if other potentially serious causes of chest pain are excluded, hemodynamic status is normal, and a moderate or large pericardial effusion is excluded by echocardiography. In the absence of a specific cause for acute peri-

carditis, anti-inflammatory therapy with nonsteroidal anti-inflammatory drugs (NSAIDs) is the mainstay of treatment.

Patients with dissection of the thoracic aorta typically present with abrupt onset of severe, sharp, or “tearing” chest pain often radiating to the abdomen, or with back pain. Although dissection is fairly rare compared to other chest pain causes (an incidence of 3 per 100,000 patients per year), it can be rapidly life threatening. Aortic dissection can be associated with syncope due to decreased cardiac output, stroke and MI caused by carotid or coronary artery occlusion/dissection, cardiac tamponade, and sudden death due to rupture of the aorta. Hypertension is present in 50% of patients and is not helpful diagnostically. A pulse differential (diminished pulse compared with the contralateral side) on palpation of the carotid, radial, or femoral arteries is one of the most useful findings but is uncommon (sensitivity of 30%; positive likelihood ratio = 5.7). An early diastolic murmur due to acute aortic insufficiency may be heard, particularly if the dissection involves the ascending aorta, but the presence or absence of a diastolic murmur is not useful in ruling in or ruling out dissection. Focal deficits on neurologic examination can be present in a few patients but are highly suggestive in the proper clinical context (positive likelihood ratio = 6.6-33.0).

In patients with dissection of the thoracic aorta, a wide mediastinum on a chest radiograph is the most common initial finding (sensitivity of 85%); the absence of this finding helps but does not completely rule out dissection (negative likelihood ratio = 0.3). When aortic dissection is suspected, imaging the aorta is indicated.

Computed tomography or magnetic resonance imaging of the chest, transesophageal echocardiography, and aortic root angiography all have a high sensitivity and specificity for detecting a dissection flap; the specific diagnostic modality chosen depends on how quickly the examination can be performed and the patient’s stability. Because of an increased risk of coronary artery dissection and tamponade with dissection progression, dissections involving the ascending aorta and

Figure 1. Electrocardiogram showing sinus rhythm with diffuse ST-segment elevation consistent with acute pericarditis. Note also the PR-segment depression in leads I, II, and V4-V6.

Approach to Chest Pain • 5

aortic arch are surgical emergencies. Dissections distal to the subclavian artery are usually treated medically to reduce the patient’s blood pressure (intravenous β-blockers followed by sodium nitroprusside, fenoldopam, or enalaprilat).

Aortic stenosis is a cause of exertional chest pain and may also be accompanied by dyspnea, palpitations, and exertional syncope due to a diminished cardiac output (see Chapter 9). Physical examination reveals a systolic, crescendo-decrescendo murmur best heard at the second right intercostal space, with radiation to the right carotid artery. A transthoracic echocardiogram is the diagnostic test of choice for patients with suspected aortic stenosis.

Patients with spontaneous esophageal rupture typically have severe retching and vomiting followed by excruciating retrosternal chest and upper abdominal pain. These symptoms are followed by the rapid development of odynophagia, tachypnea, dyspnea, cyanosis, fever, and shock. Many cases are related to excessive alcohol ingestion. Chest radiography may show pneumomediastinum, although computed tomography is more sensitive for making this diagnosis.

Patients with acute cholecystitis frequently present with right upper quadrant and lower chest pain that may radiate to the right shoulder and is associated with nausea, vomiting, and fever (see Chapter 23). On physical examination, deep palpation during inspiration can elicit pain in the right upper quadrant and cause inspiratory arrest (Murphy sign).

Pulmonary Causes Patients with PE may present with acute pleuritic chest pain (45% to 75% of cases), dyspnea, and, less often, cough and hemoptysis (see Chapter 8). Physical examination findings are nonspecific but may include tachypnea and tachycardia. ECG readings may also show findings of right ventricular strain, but the most common finding is sinus tachycardia. Well’s criteria can help precisely define pretest probability of PE and dictate further testing. A negative D-dimer, a test for PE with a high specificity but low sensitivity, can exclude the diagnosis when clinical suspicion is low. When suspicion is moderate or high, however, a spiral computed tomography scan or a ventilation-perfusion lung scan is an appropriate initial approach Pleuritic chest pain can also be a manifestation of pneumonia and is associated with fever, chills, cough, purulent sputum, and dyspnea (see Chapter 57). The physical examination may show wheezing or crackles and signs of consolidation, such as dullness to percussion, egophony, and bronchophony. Chest x-ray is considered the gold standard for pneumonia diagnosis and is an appropriate initial diagnostic test for any case of chest pain with a possible pulmonary etiology.

Pneumothorax should be considered in any patient with sudden onset of pleuritic chest pain and dyspnea (see Chapter 91). It is most common in smokers, especially those with chronic obstructive pulmonary disease. The physical examination may reveal decreased breath sounds on the affected side; if a tension pneumothorax is present, hypotension and tracheal deviation to the opposite side of the pneumothorax may be noted. Chest radiography shows a lack of lung markings on the affected side. In tension pneumothorax, there is a shift of the mediastinum away from the side of the pneumothorax, whereas hydropneumothorax is identified by the presence of concomitant pleural fluid.

Gastrointestinal Causes Gastroesophageal reflux disease (GERD) can also cause chest pain.

Although sometimes difficult to differentiate from ischemic cardiac chest pain, GERD pain often lasts minutes to hours and resolves spontaneously or with antacids (see Chapter 18). Chest discomfort associated with GERD may also depend on the patient’s position, being worse when lying down and after meals or upon awakening the patient from sleep. Other symptoms may include heartburn, regurgitation, chronic cough, sore throat, and hoarseness. On physical examination, patients may exhibit wheezing, halitosis, dental erosions, and pharyngeal erythema. In unclear cases, it is most appropriate to exclude cardiac causes of chest pain before evaluating gastrointestinal causes. For patients with a high probability of GERD, empiric treatment with a proton pump inhibitor for 4 to 6 weeks is an appropriate initial diagnostic and therapeutic approach.

Musculoskeletal Causes Musculoskeletal causes of chest pain are more common in women than in men. Frequent causes of musculoskeletal chest pain include costochondritis, arthritis, and shoulder rotator cuff injuries.

Musculoskeletal chest pain has an insidious onset and may last for hours to weeks. It is most recognizable when sharp and localized to a specific area of the chest; however, it can also be poorly localized.

The pain may be worsened by turning, deep breathing, or arm movement. Chest pain may or may not be reproducible by chest palpation; pain reproduced by palpation does not exclude ischemic heart disease. The cardiovascular examination often is normal. For musculoskeletal chest pain, the history and physical examination are keys to the diagnosis; selected radiographic studies and laboratory tests may be indicated depending on the clinical circumstances.

Psychiatric Causes Chest pain can be a manifestation of severe anxiety and panic attacks.

Patients may complain of sweating, trembling, or shaking; sensations of choking, shortness of breath, or smothering; nausea or abdominal distress; or feeling dizzy, unsteady, or lightheaded. On physical examination, tachycardia and tachypnea may be present, but the cardiovascular and pulmonary examinations are otherwise unremarkable.

Generalized anxiety and panic attacks may be treated with cognitive behavioral therapy and selective serotonin reuptake inhibitors or venlafaxine. Panic disorder stands alone among the anxiety spectrum disorders as a condition for which there is evidence that the combination of cognitive behavioral therapy and pharmacotherapy is superior to either treatment modality alone. Psychosomatic chest pain is a clinical diagnosis; other causes of chest pain are usually excluded by a careful history and physical examination.

Skin Causes Herpes zoster can present in patients with thoracic dermatomes and lead to chest pain. Pain is classically described as intense, burning, and localized to the dermatome involved. Physical exam reveals unilateral vesicular lesions, although pain often precedes the appearance of these classic lesions. Pain persisting after the disappearance of the skin findings (postherpetic neuralgia) is also common.

Bibliography Lee TH, Goldman L. Evaluation of the patient with acute chest pain. N Engl J Med. 2000;342:1187-1195. [PMID: 10770985] McConaghy JR, Oza RS. Outpatient diagnosis of acute chest pain in adults.

Am Fam Physician. 2013;87(3):177-182. [PMID: 23418761]

With IM Essentials Text, you are able to: ✔ Concisely review essential internal medicine content that will be covered in the basic medicine clerkship ✔ Provide information at the necessary depth to prepare for the end-of-rotation and USMLE Step 2 licensure exams ✔ Rapidly access background information needed when studying IM Essentials Questions or other resources for self-assessment An abbreviated textbook developed to be used during the internal medicine clerkship, IM Essentials Text is based on the national core curriculum and written by clerkship directors to cover all of the key content needed for students to get the most out of the clinical clerkship in medicine.

Organized by traditional subspecialty internal medicine topics, IM Essentials Text contains more than 250 differential diagnosis tables and treatment algorithms, as well as over 150 color plates, imaging studies, and electrocardiograms to optimize your learning.

IM Essentials Text includes FREE access to the online version of IM Essentials that combines the full content of both IM Essentials Text and IM Essentials Questions plus digital flashcards.

The interactive format allows you to: • Work at your own pace using different devices • Access more than 500 multiple-choice questions with the ability to switch back-and-forth between questions and associated text content • Create custom quizzes to focus on the content you need to study the most • Read critiques explaining why each answer is correct or incorrect • Review key point summaries for each question • Study digital flashcards to review key facts while preparing for the clerkship exam • Compare your progress to other IM Essentials users

IM Essentials Text is one part of the IM Essentials suite of study materials produced for students through a collaboration of the American College of Physicians and the Clerkship Directors in Internal Medicine. Also available is IM Essentials Questions, a companion book containing over 500 self-assessment questions, with links from each question to the related content in IM Essentials Text.

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