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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_2664_Библиотеки_им_академика_М_И_Перельмана
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Preventive Medicine
Chapter Title
Learning Objectives
❏ Describe appropriate screening methods as they apply to neoplasms of the colon,
breast, and cervix
❏ Describe epidemiological data related to incidence and prevention of common infec-
tious disease, chronic illness, trauma, smoking, and travel risks
CANCER SCREENING
A 39-year-old woman comes to the clinic very concerned about her risk of
developing cancer. Her father was diagnosed with colon cancer at age 43, and her
mother was diagnosed with breast cancer at age 52. She is sexually active with
multiple partners and has not seen a physician since a motor vehicle accident
15 years ago. She denies any symptoms at this time, and her physical
examination is normal. She asks what is recommended for a woman her age.
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1
Screening tests are done on seemingly healthy people to identify those at increased risk of disease. Even if a diagnostic test is available, however, that does not necessarily mean it should be
used to screen for a particular disease.
• Several harmful effects may potentially result from screening tests.
• Any adverse outcome that occurs (large bowel perforation secondary to a colonoscopy)
is iatrogenic.
• Screening may be expensive, unpleasant, and/or inconvenient.
• Screening may also lead to harmful treatment.
Finally, there may be a stigma associated with incorrectly labeling a patient as “sick.”
For all diseases for which screening is recommended, effective intervention must exist, and the
course of events after a positive test result must be acceptable to the patient. Most important, the
screening test must be valid, i.e., it must have been shown in trials to decrease overall mortality
in the screened population. For a screening test to be recommended for regular use, it has to be
extensively studied to ensure that all of the above requirements are met.
The 4 malignancies for which regular screening is recommended are cancers of the colon,
breast, cervix, and lung.
1
USMLE Step 2 CK
l Internal Medicine
Colon Cancer
In the patient with no significant family history of colon cancer, screening should begin at age
50. The preferred screening modality for colon cancer is colonoscopy every 10 years. Other
choices include annual fecal occult blood testing and sigmoidoscopy with barium enema every
5 years.
In the patient with a single first-degree relative diagnosed with colorectal cancer before age
60 or multiple first-degree relatives with colon cancer at any age, colonoscopy should begin
at age 40 or 10 years before the age at which the youngest affected relative was diagnosed,
whichever age occurs earlier. In these high-risk patients, colonoscopy should be repeated
every 5 years. The U.S. Preventive Services Task Force (USPSTF) does not recommend routine
screening in patients age >75.
Note
Tamoxifen prevents cancer
by 50% in those with
>1 family member with breast
cancer.
Note
Prostate Screening
USPSTF concludes that the
current evidence is insufficient
to assess the balance of
benefits/risks of prostate
cancer screening in men
age <75. It recommends
against screening in men
age >75.
For USMLE, do not screen for
prostate cancer.
Breast Cancer
The tests used to screen for breast cancer are mammography and manual breast exam.
Mammography with or without clinical breast exam is recommended every 1–2 years from
age 50–74. The American Cancer Society no longer recommends monthly self breast examination alone as a screening tool. Patients with very strong family histories of breast cancer
(defined as multiple first-degree relatives) should consider prophylactic tamoxifen, discussing
risks and benefits with a physician. Tamoxifen prevents breast cancer in high-risk individuals.
Cervical Cancer
The screening test of choice for the early detection of cervical cancer is the Papanicolaou
smear (the “Pap” test). In average risk women, screening with Pap smear should be started at
age 21, regardless of onset of sexual activity. It should be performed every 3 years until age
65. As an alternative, women age 30-65 who wish to lengthen the screening interval can do
co-testing with Pap and HPV testing every 5 years. In higher risk women, e.g., HIV, more frequent screening or screening beyond age 65 may be required.
Lung Cancer
Current recommendation s for lung cancer screening are as follows:
• Annual screening with low-dose CT in adults age 55 - 80 who have a 30-pack-year
smoking history and currently smoke or have quit within past 15 years
• Once a person has not smoked for 15 years or develops a health problem substantially
limiting life expectancy or ability/willingness to have curative lung surgery, screening
should be discontinued
TRAVEL MEDICINE
A 44-year-old executive comes to the clinic before traveling to Thailand for
business. He has no significant past medical history and is here only because
his company will not let him travel until he is seen by a physician. The patient
appears agitated and demands the physician’s recommendation immediately.
It is important to set up a pretravel counseling session 4–6 weeks before the patient’s departure.
2
Chapter 1
Hepatitis A infection is travelers’ most common vaccine-preventable disease. Hepatitis A infection is possible wherever fecal contamination of food or drinking water may occur. Infection
rates are particularly high in nonindustrial countries. If a patient is leaving within 2 weeks of
being seen, both the vaccine and immune serum globulin are recommended. A booster shot
given 6 months after the initial vaccination confers immunity for approximately 10 years.
All travelers to less-developed countries should get hep A vaccine.
Hepatitis B vaccination is recommended for patients who work closely with indigenous
populations. Additionally, patients who plan to engage in sexual intercourse with the local
populace, to receive medical or dental care, or to remain abroad for >6 months should be
vaccinated.
Malaria: Mefloquine is the agent of choice for malaria prophylaxis. It is given once per week;
it may cause adverse neuropsychiatric effects such as hallucinations, depression, suicidal ideations, and unusual behavior. Doxycycline is an acceptable alternative to mefloquine, although
photosensitivity can be problematic. For pregnant patients requiring chemoprophylaxis for
malaria, chloroquine is the preferred regimen.
Rabies vaccination is recommended for patients traveling to areas where rabies is common
among domesticated animals (India, Asia, Mexico). Chloroquine can blunt the response to the
intradermal form of rabies vaccine. Therefore, in patients who require malaria prophylaxis,
in addition to rabies prophylaxis the intramuscular form of the vaccine should be administered. Rabies vaccination is not considered a routine vaccination for most travelers.
l Preventive Medicine
Typhoid vaccination is recommended for patients who are traveling to developing countries
and will have prolonged exposure to contaminated food and water. Typhoid vaccination
comes in 2 forms, an oral live attenuated form and a capsular polysaccharide vaccine given
parenterally. The live attenuated form (1) needs to be refrigerated, and (2) is contraindicated
in patients who are HIV positive. The polysaccharide vaccine is given intramuscularly as a
single injection. Side effects include irritation at the injection site. Fever and headache are rare
adverse reactions to the vaccine. The polysaccharide vaccine is the preferred form for almost
all subjects as it is well-tolerated and convenient (no need for refrigeration). It is safe for HIV
patients.
Polio: Adults who are traveling to developing countries and have never received a polio vaccine should receive 3 doses of the inactivated polio vaccine. Patients who have been previously
immunized should receive a one-time booster. The live attenuated polio vaccine is no longer
recommended because of the risk of vaccine-associated disease.
Patients traveling to areas where meningococcal meningitis is endemic or epidemic (Nepal,
sub-Saharan Africa, northern India) should be immunized with the polysaccharide vaccine. Additionally, Saudi Arabia requires immunization for pilgrims to Mecca. Patients with
functional or actual asplenia and patients with terminal complement deficiencies should also
receive the vaccine. Meningococcal vaccine is now routinely administered at age 11.
To prevent traveler’s diarrhea, patients should be advised to avoid raw and street vendor salads,
unwashed fruit, and tap/ice water. Patients who experience mild loose stools without fever or
blood can safely take loperamide. Treatment with a fluoroquinolone or azithromycin is reserved
for patients with moderate to severe symptoms.
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USMLE Step 2 CK
l Internal Medicine
IMMUNIZATIONS
Note
Patients must get pneumovax,
meningococcal, and
Haemophilus vaccines 2 weeks
before a splenectomy.
A 52-year-old man comes to the clinic for a health maintenance evaluation. His
recent colonoscopy showed no evidence of carcinoma. Recent serum fasting
glucose, serum cholesterol, and blood pressure measurements are all within
normal limits. The patient has a history of smoking, continues to smoke 2 packs
per day, and was diagnosed with COPD 3 years ago.
Immunization is the best method available to prevent serious infectious disease. Between
50,000 and 70,000 adults die every year from preventable infectious diseases (influenza, invasive pneumococcal disease, and hepatitis B). Surveys have shown that among patients who
have an indication for any vaccination, very few actually receive it (pneumococcal vaccination 20%, influenza 40%, hepatitis B 10%). It is for this reason that the American College of
Physicians recommends that every patient’s immunization status should be reviewed at age
50. Risk factors that would indicate specific vaccinations should be evaluated at that time.
Most patients received a primary immunization against tetanus and diphtheria as children.
Adults who were never vaccinated should receive a total of 3 doses, the first 2 of which are given
1 to 2 months apart, with the third dose given 6 to 12 months later. The principle is that adults
require a total of 3 vaccinations against tetanus and diphtheria. A booster vaccination should be
given every 10 years for life. One of the boosters should use Tdap instead of Td booster. If the
wound is dirty, revaccinate after 5 years.
Influenza Vaccine
Recommended annually for all adults regardless of age. Patients who have a history of cardiopulmonary disease, diabetes mellitus, or hemoglobinopathy, or are age 50+ residents
of chronic care facilities derive the greatest benefit from an annual influenza vaccination.
Pregnant women who will be in their second or third trimester during the influenza season
should also receive the vaccine.
Pneumococcal Vaccine
Indicated for all adults age ≥65. Additionally, patients with a history of sickle-cell disease or
splenectomy, those who have a history of cardiopulmonary disease, alcoholism, or cirrhosis,
and Alaskan natives and certain Native American populations should receive the vaccine
regardless of age. Immunocompromised patients (patients with hematologic malignancies,
chronic renal failure, or nephrotic syndrome; HIV-positive patients; or patients receiving
immunosuppressive medications) should also receive the vaccine at any age. Revaccination
should be performed in healthy patients who received their initial vaccination age <65 and
were age <60 at the time of primary vaccination. Patients with a high risk of fatal infection
(CKD, asplenic patients, immunocompromised patients) should be revaccinated once after 5
years. No one gets >1 booster shot per lifetime.
Hepatitis B Vaccine
Recommended when there is a history of IV drug abuse, male homosexuality, household
or sexual contact with hepatitis B carriers, or frequent exposure to blood or blood products. Additionally, patients with a history of chronic liver disease should receive the vaccine.
4
Chapter 1
Immunity is confirmed serologically. Also recommended for all children through age 18,
those with STIs, those who are sexually active but not monogamous, workers with occupational exposure to blood, and prison inmates.
Hepatitis A Vaccine
The vaccine against hepatitis A protects against the virus in >95% of cases. There are 2 types
of vaccine; both types stimulate active immunity against a future infection.
• One contains inactivated hepatitis A virus
• One contains a live but attenuated virus
For the best protection, the vaccine should be given in 2 doses; a booster should follow up the
initial dose 6-12 months later. Protection against hepatitis A begins approximately 2-4 weeks
after the initial vaccination. Those who miss the follow-up booster dose should receive only
the remaining booster dose.
In the United States, the vaccine is strongly recommended for all children age 12-23 months
in an attempt to eradicate the virus nationwide. There are also recommendations that the following populations should be vaccinated:
• All children age >1 year
• People whose sexual activity puts them at risk
• People with chronic liver disease
• People who are being treated with clotting factor concentrates
• People who are living in communities where an outbreak is present
l Preventive Medicine
Hepatitis A is the most common vaccine-preventable virus acquired during travel, so people
travelling to places where the virus is common (Indian subcontinent, Africa, Central America,
South America, the far East, and Eastern Europe) should be vaccinated.
Varicella Vaccine
A live attenuated vaccine recommended for use in all adults who lack a history of childhood
infection with varicella virus. Being a live attenuated vaccine, varicella vaccine should not be
given to immunocompromised patients, HIV-positive patients when symptomatic or <200
CD4 cells, or pregnant women.
Patients age ≥60 are recommended to receive the varicella zoster (shingles) vaccine, which
has been shown to reduce the risk of zoster and its associated pain (post-herpetic neuralgia). It is indicated regardless of whether there is a history of shingles, as it is possible to
have a second herpes zoster infection.
Measles, Mumps, Rubella (MMR) Vaccine
A live attenuated vaccine usually given in childhood. Healthy adults born after 1956 should
receive one dose of the vaccine. Pregnant women and immunocompromised patients should
not be vaccinated. HIV-positive patients who are asymptomatic may receive the vaccine.
5
USMLE Step 2 CK
l Internal Medicine
Meningococcal Vaccine
Recommended for everyone at age 11 visit. Also recommended for young adults living in
dormitories or barracks, people exposed to outbreaks, those with asplenia or terminal complement deficiencies, those who travel to endemic regions (traveling to Mecca), and those
exposed to Neisseria menigitidis.
Human Papillomavirus (HPV) Vaccine
Recommended for women age 9-26, regardless of sexual activity. Do not use in pregnancy.
Regimen is in 3 doses: 0, 2, and 6 months.
Herpes Zoster Vaccine
The zoster vaccine is a live vaccine that has been shown to reduce the incidence of shingles by
50%. It has also been shown to reduce the number of cases of post-herpetic neuralgia, as well
as the severity and duration of pain/discomfort associated with shingles. The vaccine is, basically, a larger-than-normal dose of the chicken pox vaccine, as both shingles and chickenpox
are caused by the same virus, varicella zoster (VZV).
The shingles vaccine (Zostavax) is recommended for adults age ≥60, whether they have
already had shingles or not. The shingles vaccine is a live vaccine given as a single injection.
Some people report a chickenpox-like rash after receiving it. The vaccine should NOT be
given to:
• Those with a weakened immune system due to HIV/AIDS or another disease that
affects the immune system
• Those who are receiving immune system-suppressing drugs or treatments, such as steroids, adalimumab (Humira), infliximab (Remicade), etanercept (Enbrel), radiation or
chemotherapy
• Those who have neoplasia, which affects the bone marrow or lymphatic system, such
as leukemia or lymphoma
SMOKING CESSATION
A 25-year-old man comes to the clinic for evaluation of a stuffy nose and fever.
Over the course of the interview the patient states that he smokes 3 packs of
cigarettes per day and has been doing so for the last 7 years.
Smoking is responsible for 1 in every 5 deaths in the United States. Smoking cessation is the
most preventable cause of disease. Physicians can take the following steps to assist:
ASK about smoking at every visit.
ADVISE all smokers to quit at every visit.
ATTEMPT to identify those smokers willing to quit.
ASSIST the patient by setting a quit date (usually within 2 weeks) and using nicotine patches/
gum, the oral antidepressant bupropion or varenicline as supportive therapy. Varenicline and
bupropion are more effective than patches.
6
Chapter 1
ARRANGE follow-up. Provide positive reinforcement if the quit attempt was successful. If the
quit attempt was not successful, then determine why the patient smoked and elicit a recommitment to smoking cessation. Most patients will require several attempts before being successful.
l Preventive Medicine
Monotherapy treatment for smoking cessation includes nicotine replacement therapy (transdermal nicotine patches, gum, lozenges, inhalers), bupropion, and varenicline. Bupropion
lowers the seizure threshold so do not use in cases of alcohol abuse. With varenicline, screen
first for depression since it causes increased rate of suicidal thoughts.
Place a follow-up call 1-2 weeks after quit date. The use of pharmacotherapy doubles the
effect of any tobacco cessation intervention.
OSTEOPOROSIS
All women age >65 should be given DEXA bone density scan. Screening should begin at age
60 if there is low body weight or increased risk of fractures. A bone density test uses x-rays to
measure how many grams of calcium and other bone minerals are packed into a segment of
bone. The bones that are tested are in the spine, hip and forearm. Bone density test results are
reported in 2 numbers: T-score and Z-score.
The T-score is the bone density compared with what is normally expected in a healthy young
adult of the same sex. The T-score is the number of units—standard deviations—that bone
density is above or below the average. T-score >2.5 SD indicates the likelihood of osteoporosis
and increased risk of fracture. The diagnosis of osteoporosis by DEXA scan also means that
treatment should be initiated with bisphosponates, oral daily calcium supplementation, and
vitamin D.
The Z-score is the number of standard deviations above or below what is normally expected
for someone of the same age, sex, weight, and ethnic or racial origin. Z-score ≤-2 may suggest
that something other than aging is causing abnormal bone loss (consider drugs causing osteoporosis such as corticosteroids). The goal in this case is to identify the underlying problem.
Note
Varenicline should not be
used in patients with a history
of psychiatric disease.
ABDOMINAL AORTIC ANEURYSM
U/S should be done once in men age >65 who have ever smoked. There are no screening recommendations for male nonsmokers and women, regardless of smoking history.
HYPERTENSION, DIABETES MELLITUS, AND
HYPERCHOLESTEROLEMIA
A 45-year-old man comes to the physician anxious about his health. Five years ago
his mother was diagnosed with diabetes and high cholesterol. He is worried about
his health and risk for heart disease. Physical examination is within normal limits.
Cholesterol screening should commence at age 35 in men who have no risk factors. In both
men and women with risk factors for coronary artery disease, screening should be done routinely after age 20. Management should not be determined by an isolated reading because cholesterol levels may fluctuate between measurements. Repeat in 5 years in low-risk individuals.
7
USMLE Step 2 CK
l Internal Medicine
Screening for diabetes mellitus should be considered only for patients with hypertension
(>135/80 mm Hg). Diabetes mellitus is diagnosed when:
• 2 fasting glucose measurements are >125 mg/dL, HbA1c > 6.5%, or
• random glucose >200 mg/dL accompanied by symptoms
There is insufficient evidence for or against routine screening. The strongest indication is for
those with hypertension and hyperlipidemia.
Screening is recommended for elevated blood pressure in those age >18, at every visit.
Screening is not recommended for carotid artery stenosis with duplex.
ALCOHOL ABUSE
A 55-year-old man comes to the office for evaluation of a sore throat. The patient
admits that he was recently fired from his job and is having marital problems
at home. The patient has no significant past medical history, and physical
examination is within normal limits. He attests to drinking 3 shots of whiskey every
day after work.
Physicians should screen for alcohol abuse by using the CAGE questionnaire:
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?
A positive screen is 2 “yes” answers. One “yes” should raise the possibility of alcohol abuse.
PREVENTION OF VIOLENCE AND INJURY
A 27-year-old woman presents to the emergency department complaining of
right-arm pain. When asked how she sustained the injury, she states that she fell
down the steps in front of her house. The patient appears anxious and nervous.
On physical examination there are various 2 cm wide lacerations on her buttocks.
Injuries are the most common cause of death in those age <65. The role of the physician is
to advise patients about safety practices that can prevent injury, e.g., using seat belts, wearing
bicycle helmets, and not driving after drinking alcohol.
Identifying women who are at increased risk of physical or sexual abuse is an essential role for
physicians. Simply asking women if they have been hit, kicked, or physically hurt can increase
identification by >10%.
8
Endocrinology
Chapter Title
Learning Objectives
❏ List presenting signs and therapeutic approaches to disease of the anterior
pituitary, posterior pituitary, thyroid, parathyroid, and adrenal glands
❏ Describe disorders that cause hypogonadism or affect the testes
❏ Describe disorders of carbohydrate metabolism
DISEASES OF THE PITUITARY GLAND
The pituitary is surrounded by the sphenoid bone and covered by the sellar diaphragm, an
extension from the dura mater. It lies in the sella turcica near the hypothalamus underneath
the optic chiasm.
00
2
The pituitary is divided into 2 lobes—the adenohypophysis or anterior lobe, which constitutes 80% of the pituitary, and the neurohypophysis or posterior lobe, which is the storage
site for hormones produced by the neurosecretory neurons (supraoptic and paraventricular
nuclei) within the hypothalamus. The 2 hormones stored in the posterior lobe are ADH
(antidiuretic hormone or vasopressin) and oxytocin.
There is a very close relationship between the hypothalamus and the pituitary. The hypothalamus regulates the release of hormones from the anterior pituitary by different hypothalamic releasing and inhibiting hormones (hypothalamic–pituitary axis).
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