USMLE Step 3 Lecture Notes 2017-2018: Internal Medicine, Psychiatry, Ethics (USMLE Prep)

Section I: Internal MedicineChapter 1: Preventive Medicine Cancer ScreeningTravel MedicineImmunizationsSmoking CessationOsteoporosis PreventionPrevention of Alcohol AbusePrevention of Vi

USMLE ® Step 3

2017–2018 Lecture Notes

Internal Medicine

Psychiatry Ethics

Section I: Internal Medicine

Chapter 1: Preventive Medicine

Cancer ScreeningTravel MedicineImmunizationsSmoking CessationOsteoporosis PreventionPrevention of Alcohol AbusePrevention of Violence and InjuryChapter 2: Infectious Disease

Case 1Case 2Case 3Case 4Case 5Case 6Case 7Case 8Case 9Case 10Case 11Case 12Case 13Case 14Case 15Chapter 3: Cardiology

Case 1Case 2Case 3Case 4Case 5Case 6Case 7Case 8Case 9Case 10Case 11Case 12Chapter 4: Pulmonology

Case 1

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National Board of Medical Examiners (NBME), neither of which sponsors or endorses thisproduct

This publication is designed to provide accurate information in regard to the subject mattercovered as of its publication date, with the understanding that knowledge and best practiceconstantly evolve The publisher is not engaged in rendering medical, legal, accounting, orother professional service If medical or legal advice or other expert assistance is required, theservices of a competent professional should be sought This publication is not intended for use

in clinical practice or the delivery of medical care To the fullest extent of the law, neither thePublisher nor the Editors assume any liability for any injury and/or damage to persons orproperty arising out of or related to any use of the material contained in this book

Editors INTERNAL MEDICINE

Charles Faselis, M.D.

Chairman of Medicine

VA Medical Center Washington, DC

Professor of Medicine George Washington University School of Medicine

Washington, DC

Joseph J Lieber, M.D.

Associate Professor of Medicine Associate Program Director in Medicine

Site Director, Internal Medicine Residency Program

Mount Sinai School of Medicine

Assistant Professor of Internal Medicine

Site Director, Internal Medicine Clerkship and Sub-Internship

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Icahn School of Medicine at Mount Sinai

New York, NY

Hospitalist Elmhurst Hospital Center

Queens, NY

Manuel A Castro, M.D., AAHIVS

Diplomate of the American Board of Internal Medicine Certified by the American Academy of HIV Medicine Wilton Health Center (Private Practice)

Wilton Manors, FL

Nova Southeastern University Clinical Assistant Professor of Medicine Fort Lauderdale-Davie, FL

LECOM College of Osteopathy Clinical Assistant Professor of Medicine

Bradenton, FL

Raj Dasgupta, M.D., F.A.C.P., F.C.C.P., F.A.A.S.M.

Assistant Professor of Clinical Medicine Department of Medicine, Division of Pulmonary, Critical Care and Sleep Medicine

Assistant Program Director of Internal Medicine residency

Associate Program Director of Sleep Medicine fellowship

Keck School of Medicine of USC

Los Angeles, CA

PSYCHIATRY AND ETHICS

Alina Gonzalez-Mayo, M.D.

Psychiatrist Dept of Veteran’s Administration

Bay Pines, FL

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at medfeedback@kaplan.com.

Section I

INTERNAL MEDICINE

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colonoscopy starting at one of the following, whichever age occurs earlier:

Colonoscopy every 10 years (preferred screening modality)

Fecal occult blood testing every year

Sigmoidoscopy with barium enema every 5 years

Age 40

Age that is 10 years younger than the age at which the youngest affected relative was

In this group of high-risk patients, colonoscopy should be repeated every 5 years.

Breast Cancer

The 3 tests used to screen for breast cancer are mammogram, manual breast exam, and breast exam The American Cancer Society no longer recommends monthly self-breast examalone as a screening tool

Current lung cancer screening guidelines recommend the following:

Patients age ≥50, screen with mammogram (with or without clinical breast exam) every 1–2years

Patients with very strong family history should consider prophylactic tamoxifen

“Very strong family history” is defined as multiple first-degree relatives

Patients age <30, screen annually if using conventional methods or every 2 years if usingliquid-based methods

Patients age ≥30, screen every 2 years if >3 normal annual PAP smears

Patients age 55–80 with >30 pack-years of smoking, screen annually with low dose CT(non-contrast)

Must be current smoker or has quit ˂15 years

—

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Patients age >80, have quit >15 years, or have other medical problems (e.g., severe COPD)significantly limiting life expectancy or ability to undergo surgery, no screening is

recommended

Travel Medicine

Hepatitis

Hepatitis A infection is travelers’ most common vaccine-preventable disease Hepatitis Ainfection is possible wherever fecal contamination of food or drinking water may occur If apatient is leaving within 2 weeks of being seen, both the vaccine and immune serum globulinare recommended

A booster shot given 6 months after the initial vaccination confers immunity for approximately

10 years

Hepatitis B vaccination is recommended for patients who work closely with the indigenouspopulation Additionally, patients who plan to engage in sexual intercourse with the localpopulace or to receive medical or dental care, and those who plan to remain abroad for >6months, should be vaccinated

Malaria

For travel to Mexico, Central America (except to Panama), or the Caribbean, chloroquine isacceptable prophylaxis for malaria For travel to areas where chloroquine resistance iscommon, mefloquine is the agent of choice Doxycycline is an acceptable alternative tomefloquine, although photosensitivity can be problematic

For patients who are pregnant and require chemoprophylaxis for malaria, the combination ofatovaquone and proguanil is the preferred regimen

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Patients traveling to areas where meningococcal meningitis is endemic or epidemic (Nepal,sub-Saharan Africa, northern India) should be immunized with the polysaccharide vaccine

functional or actual asplenia and patients with terminal complement deficiencies should alsoreceive the vaccine Meningococcal vaccine is now routine to give at age 11.

Diarrhea

To prevent traveler’s diarrhea, patients should be educated regarding the advisability ofavoiding salads and unwashed fruit and drinking tap/ice water Patients who experience loosestools without fever or blood can safely take loperamide Treatment with a fluoroquinolone orazithromycin is reserved for patients with moderate to severe symptoms (bloody diarrhea)

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Influenza Vaccine

Influenza vaccination is recommended annually for all adults, regardless of age Additionally,those who have a history of cardiopulmonary disease, DM, or hemoglobinopathy, or who areresidents of a chronic care facility should receive an annual influenza vaccination, regardless

Additionally:

Those with history of sickle-cell disease or splenectomy

Those with history of cardiopulmonary disease, alcoholism, or cirrhosis

Alaskan natives and certain Native American populations

Those who are immunocompromised (hematologic malignancy, chronic renal failure,nephrotic syndrome, HIV-positive; or taking immunosuppressive medications)

Varicella Vaccine

Varicella vaccine is a live, attenuated vaccine recommended for use in all adults who lack ahistory of childhood infection with varicella virus Being a live, attenuated vaccine, varicellavaccine should not be given to immunocompromised patients, HIV-positive patients whensymptomatic, those with <200 CD4 cells, or pregnant women

Shingles Vaccine

The shingles (zoster) vaccine is recommended routinely in order to reduce the risk of shinglesand its associated pain in people ≥60 Only one dose of zoster vaccine is typically given.Persons who report a previous episode of zoster and persons with chronic medical condition(chronic kidney disease, diabetes) can be vaccinated

Zoster vaccination is not indicated to treat acute zoster, to prevent those with acute zoster from

developing post-herpetic neuralgia, or to treat ongoing post-herpetic neuralgia Before routineadministration of zoster vaccine, it is not necessary to ask patients about their history of

varicella (chickenpox) or to conduct serologic testing for varicella immunity The zoster

vaccine is a lyophilized preparation of live, attenuated VZV

HPV Vaccine

The quadrivalent human papilloma virus (HPV) vaccine prevents against 4 types of HPV (types

6, 11, 16, 18) that are associated with genital warts and cervical cancer It is given in 3 dosesand it is recommended for those age 11–12, but can be given at age 9

been more than 5 years since being vaccinated

Those with high risk of fatal infection (asplenic patients, immunocompromised patients,kidney disease, chemotherapy, long-term steroids, cancer including leukemia and lymphoma,organ transplant) should be revaccinated 1x after 5 years

No one gets more than 1 booster shot per lifetime

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It is also recommended for those who did not complete the series or were never vaccinatedfrom age 13–26 Males age 9–26 might get the vaccine to prevent genital warts Cervicalcancer screening with Pap smear should continue after vaccination.

Smoking Cessation

Smoking cessation is the most preventable cause of disease Smoking is responsible for 1 inevery 5 deaths in the United States There are 5 steps a physician can take to help patients stopsmoking

U/S should be given once in male smokers age >65 in order to screen for abdominal aorticaneurysm There are no screening recommendations in male nonsmokers and women,

regardless of smoking history

ASK about smoking at every visit

ADVISE all smokers to quit at every visit

ATTEMPT to identify those smokers willing to quit

ASSIST smokers in quitting by setting a quit date (usually within 2 weeks) and usingnicotine patches/gum or the oral antidepressant bupropion as supportive

therapy Varenicline, a nicotinic receptor partial agonist, can also be used to treat nicotineaddiction

ARRANGE follow-up Provide positive reinforcement if the quit attempt was successful Ifthe quit attempt was not successful, then determine why the patient smoked and elicit arecommitment to smoking cessation Most patients will require several attempts beforebeing successful

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Osteoporosis Prevention

All women age >65 should be given a DEXA scan Screening should begin at age 60 if there islow body weight or increased risk of fractures

Prevention of Alcohol Abuse

Physicians should screen for alcohol abuse by using the CAGE questionnaire:

A positive screen is 2 “yes” answers One “yes” should raise the possibility of alcohol abuse

Have you ever felt the need to: Cut down on your drinking?

Have you ever felt: Annoyed by criticism of your drinking?

Have you ever felt: Guilty about your drinking?

Have you ever taken a morning: Eye opener?

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Prevention of Violence and Injury

Injuries are the most common cause of death age <65 The role of the physician is to advisepatients about safety practices that can prevent injury Advising the patient about the

importance of seat belts, bicycle helmets, not driving after one drinks alcohol, and

understanding the risks that firearms pose in the home can all reduce the risk of serious injury

Identifying women who are at increased risk of physical or sexual abuse is an essential role forphysicians Simply asking women if they have been hit, kicked, or physically hurt can increaseidentification by more than 10%

Infectious Disease

Case 1

Chief Complaint

Fever, cough, and chest pain

History and Physical Examination

A 32-year-old man comes to the emergency department with 5 days of fever, a cough that

is sometimes productive of blood, and pleuritic chest pain He is an active IV drug userand last used yesterday He denies being HIV positive Past medical history is significantfor skin abscesses in the past, but recently he has been quite well He uses no medicationsand has no allergies His T is 39 C (102.2 F), BP is 112/72 mm Hg, and pulse is 110/min

Physical examination reveals a thin, weak-appearing man lying on his side in the stretcher.Examination of the head, eyes, ears, nose, and throat shows petechiae in his mouth and inthe conjunctivae Eye grounds are normal The chest is bilaterally clear to auscultation A2/6 systolic ejection murmur is audible over the lower left sternal border There is noradiation of the murmur The abdomen is benign and the extremities have no clubbing, butthin red lines are visible under the fingernails in the distal 1/3

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Methicillin-sensitive Staphylococcus aureus

Multiple nodular lesions visible bilaterally

Results of cultures will not be given at the beginning of your ID cases Treatment is

empiric

Assessment

Any active IV drug abuser presenting with fever may have acute endocarditis This patient alsohas a cough, hemoptysis, and pleuritic chest pain IV drug users are also at risk for pneumonia.However, this patient has a heart murmur, and the pulmonary symptoms combined with

multiple, bilateral nodular lesions on chest x-ray most likely represent septic emboli to thelungs from the right side of the heart The tricuspid valve is most commonly involved in drugabusers (50% of the time), with aortic valve involved 25% and mitral valve 20%

The conjunctival petechiae and splinter hemorrhages are also indicative of endocarditis in boththe acute and subacute forms Roth spots (retinal lesions), Janeway lesions (flat, painless,purplish lesions on the hands and feet), and Osler nodes (pea-sized, painful nodules that

usually occur on the pads of the fingers and toes and on the palms) are usually associated withsubacute endocarditis Most of the embolic phenomena are quite rare, and their absence shouldnever dissuade you from suspecting endocarditis

Further Management Plan/Results

Further Management

Echocardiogram: vegetation visible on tricuspid valve with tricuspid regurgitation

IV antibiotics (e.g., nafcillin or oxacillin) for 4–6 wks, with gentamicin for first week

If acute decompensation occurs, surgical replacement of valve; also consider surgery formyocardial abscess, repeated emboli, very large vegetations, fungal endocarditis, or

prosthetic valve endocarditis

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Always take 3 sets of blood cultures before starting the antibiotics within 1 hr.

A transthoracic echocardiogram (TTE), with sensitivity of only 60%, should be done first.Detection of a vegetation is a positive test If it is negative, then perform a transesophagealechocardiogram (TEE), with sensitivity of 95%

Patients with abnormal findings on TTE who may require further evaluation by TEE includethose with significant valvular regurgitation to determine need for surgery, and those with ≥1risk factors for perivalvular abscess including new conduction delay on ECG, aortic valveendocarditis, and persistent bacteremia or fever despite appropriate antimicrobial therapy

S aureus accounts for 60–90% of endocarditis in IV drug abusers, and, depending on local conditions, a large percentage of this may be methicillin-resistant A large portion of S aureus

endocarditis cases are attributed to healthcare-associated bacteremia Vancomycin and

gentamicin is good empiric coverage until the results of blood cultures are known

Native valve subacute endocarditis is caused by Streptococci 50–60% of the time Viridans

streptococci, which are normal inhabitants of the mouth, account for 75% of these

of the colon Staphylococci account for about 30% of native valve subacute endocarditis, and

90% of this is S aureus Enterococci account for 5 to 10% of cases.

Culture-negative endocarditis is caused by the HACEK organisms The name is formed fromtheir initials:

Prosthetic valve endocarditis is caused most often by Staphylococci in the early postoperative

period Staphylococcus epidermidis is more common in the first 2 mos after the replacement Currently, CHF is the most common cause of death As time goes on, Streptococcus viridans

becomes more common

Other complications of endocarditis are embolic phenomena to the brain, causing abscess andmycotic aneurysm; renal infarction and abscess; and splenomegaly The most common

complication is CHF from valvular degeneration In the pre-antibiotic era, glomerulonephritiswas far more common Strokes and major systemic embolic events are present in about 25% ofpatients within 1 week of therapy

This patient has methicillin-sensitive S aureus, and nafcillin (or oxacillin or cefazolin) should

be used for 4 wks; they are usually used with gentamicin or another aminoglycoside for the first

This patient will likely need 6 wks of antibiotics because of the vegetation and evidence ofseptic emboli in the lungs.

For patients with native valve subacute endocarditis from a sensitive S viridans, penicillin G

or ceftriaxone for 4 wks alone is often sufficient Alternatively, use gentamicin plus either

aqueous crystalline penicillin G or ceftriaxone for 2 wks, in the absence of renal insufficiency

Enterococcus is best treated with a beta-lactam antibiotic such as penicillin or ampicillin, in

combination with an aminoglycoside (gentamicin or streptomycin) for the entire 4 to 6 wks

HACEK organisms are treated with ceftriaxone, ampicillin-sulbactam, or ciprofloxacin for 4

wks

If the patient has urticarial rash to vancomycin or MIC for vancomycin is >2, use daptomycin totreat right-sided MRSA endocarditis Daptomycin is used for MRSA skin and soft tissue

infection, right-sided endocarditis, and bacteremia, usually due to line sepsis Do not use

daptomycin for pneumonia, as it is inactivated by surfactants

CLINICAL PEARL

Oxacillin, nafcillin, and cefazolin are the best antibiotics for MSSA

Daptomycin inserts into the cell membrane, where it then aggregates The aggregation of

daptomycin creates holes that leak ions This causes rapid depolarization, resulting in a loss ofmembrane potential leading to inhibition of protein, DNA and RNA synthesis, which results inbacterial cell death

Infective endocarditis prophylaxis is recommended for patients with the following yield):

(high-Other rules to follow:

Evidence of uncontrolled infection can mean persistence of positive blood cultures whilealready on therapy, recurrent emboli formation of myocardial or valvular ring abscesses, orspread of the infection to involve the conduction system of the heart

Acute heart failure indicates degeneration of the valves, papillary muscles, or chordaetendinea sufficient to cause evidence of CHF

Valvular regurgitation

Recurrent embolic event because of a large vegetation

Prosthetic cardiac valve

Previous episode of infective endocarditis

Congenital heart disease characterized by unrepaired cyanotic congenital heart disease,including palliative shunts and conduits; a completely repaired congenital heart defect withprosthetic material or device during the first 6 months after the procedure; and repairedcongenital heart disease with residual defects

Cardiac transplantation recipients in whom cardiac valvulopathy develops

Antibiotic prophylaxis is recommended for all dental procedures which involve

manipulation of gingival tissue or periapical region of the teeth or perforation of oral

mucosa; limit to patients with the cardiac conditions mentioned above

Antibiotic prophylaxis is no longer recommended for any GI or GU procedure

Antibiotic prophylaxis is reasonable for procedures on the respiratory tract which involveincision or biopsy (e.g., tonsillectomy, bronchoscopic biopsy), and on infected skin, skinstructures and musculoskeletal tissue; limit to patients with the cardiac conditions mentionedabove

For those who need prophylactic antibiotics, give amoxicillin 30–60 minutes before the

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Final Diagnosis

Acute bacterial endocarditis

Basic Science Correlate

CLINICAL PEARL

Libman-Sacks endocarditis is due to sterile vegetations which arise in association withSLE Vegetations are present on and under the surface of the mitral valve, and result inmitral regurgitation (Think of this in a young female with rash, joint pain and MR

procedure

In cases of penicillin-allergy, give clindamycin, cephalexin, or a macrolide

Streptococcus viridans is the most common overall organism to cause endocarditis.

It is a low-virulence organism that infects previously damaged valves (MVP orchronic rheumatic heart disease because of valve scarring) Subacute endocarditis istypically associated with small vegetations that do not destroy the valve

Staphylococcus aureus is a high virulence organism associated with IV drug use It

results in large vegetations which rapidly destroy the valve

Staphylococcus epidermidis is associated with endocarditis of prosthetic valves

within 2 months after surgery

Streptococcus bovis is associated with colorectal cancer.

Case 2

Chief Complaint

Pain and swelling of left leg

History and Physical Examination

A 72-year-old white man with a history of prostatic cancer metastatic to bone and thelymphatic system comes to the emergency department because of a several-day history ofincreasing swelling and erythema of left leg from the knee down He denies shortness ofbreath or chest pain The patient feels warm His T is 38.4 C (101.1 F)

Physical examination reveals a left leg that is swollen and erythematous below the knee,moderately tender and warm to touch; there is no palpable fluid collection or skin

Test Results

Assessment

With a unilateral red, tender, warm, swollen leg without evidence of deep venous thrombosis,cellulitis is the most likely possibility No further diagnostic tests are required The primarymeans of diagnosing cellulitis is by clinical examination and history

Venography is not the first test to exclude a thrombosis, even though it is slightly more

sensitive and specific than U/S This is because of the risk of renal toxicity in the elderly orallergic reaction from exposure to the required contrast agent Venogram is done if the

suspicion for a clot is very high and U/S is negative

Specific microbiologic diagnosis is not routinely indicated This is sometimes done in

unresponsive cases by injecting a small amount of saline subcutaneously into the leading edge

of the infection Then, aspirate and send the sample for culture

CCS NOTE

A specific microbiologic diagnosis is almost never obtained at any point in the clinicalmanagement of a skin infection Treatment is both initiated and continued on an empiricbasis

Treatment Plan

Duplex U/S scan of venous system of the leg

No evidence of thrombosis

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The most likely organisms in cellulitis are group A streptococci (S pyogenes) and S aureus.

The magnitude of CA-MRSA infections has reached epidemic proportions in the United States.Certain risk factors have been described which put certain groups at higher risk:

IV antibiotics with oxacillin or nafcillin

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Elevation of leg and warm soaks

2

Oral dicloxacillin (mild cases); if mild penicillin allergy such as rash, use oral

cephalexin; if life-threatening penicillin allergy such as anaphylaxis, use clindamycin,macrolides, and new fluoroquinolones

3

Mild infections can be treated in the outpatient setting with oral dicloxacillin or oral

cephalosporins

For moderate cellulitis or cellulitis that does not resolve with oral treatment, a

first-generation IV cephalosporin such as cefazolin or cephalexin is appropriate

In cases of severe penicillin allergy (e.g., anaphylaxis), vancomycin or clindamycin is used.Rates of cross-reaction between penicillin and cephalosporins are <5% For reactions thatwere originally just a rash, cephalosporins are safe to use

Antibiotics are continued until symptoms have resolved Duration of treatment variesdepending on how long it takes to improve

Vancomycin cannot be used orally to treat cellulitis because it is not absorbed

Household contacts of patients with proven CA-MRSA infection

Children

Men who have sex with men (MSM)

Injection drug users

Athletes engaged in contact sports