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for all your First Aid updates
Feb 27th
Step 1: What is the rate limiting enzyme in de novo purine synthesis?
Feb 26th
Step 1: What is the rate limiting enzyme in glycogenolysis?
Feb 26th
The Step 2 Clinical Skills (CS) exam uses “standardized patients [SP] to test medical students and graduates on their ability to gather information from patients, perform physical examinations, and communicate their findings to patients and colleagues” (USMLE).
To get started, register for the exam at one of five regional centers. Plan ahead as sites fill quickly:
http://www.usmle.org/Examinations/step2/step2cs_registration.html
The exam itself lasts about 8 hours, with 2 breaks (30 minutes and 15 minutes), and includes approximately 12 patient encounters. As you interview patients, you are observed through a one-way window for scoring and quality assurance. You will have 15 minutes to gather a history and conduct a focused physical exam, followed by 10 minutes to complete a PN (written or typed, your choice). A 5-minute warning is provided during the patient encounter.
Practice typing in a patient note (the “PN”), which includes the History, Physical Exam, Differential Diagnosis and Diagnostic Workup:
http://www.usmle.org/Orientation/2010/PatientNote/EntryFrame.htm
Familiarizing yourself with the PN in advance will help you to organize your thoughts accordingly during pre-examination practice cases with the help of review texts or your friends.
First Aid for the USMLE Step 2 CS, Third Edition was recently released in October 2009. This review text contains reviews of each of the five regional centers, including advice on travel and accommodations as well as tourist destinations. Particularly if you must fly out to reach a site, you may as well stop to enjoy the trip if possible! The book also contains insights into the exam, minicases, and 41 full practice cases complete with SP guidance and PN.
Finally, relax. According to the latest performance data (2008), 97% of MD candidates in the US/Canada will pass this test on the first go. There is considerably more anxiety among IMGs, for whom the rate is 72% (the CIS and SEP scores are often the culprits), but as with any of the USMLE exams, adequate preparation is the key to confidence and success.
Feb 25th
Case 17 – A 29-year-old woman with substance dependence
A 26-year-old G7P3 woman at 34 weeks’ gestation presents to the emergency department because she feels she is beginning to experience contractions and does not have an obstetrician to consult. On examination her pupils are dilated and she appears agitated and nervous. She then changes her mind and says she does not want further evaluation because it has been too long since her last “smoke.” She is adamant about needing to leave right away. Upon further questioning, she states that if she does not get to smoke soon, she will become very sleepy and depressed, and will have intense food cravings. She has been in inpatient drug rehabilitation twice but always relapses back to her drug of choice. She is currently living at a halfway house, is on welfare, and does not have custody of any of her 3 children. “They will probably take this one away from me, too,” she adds as she begins to cry. She says she used to be able to get high for $10 per day, but now it costs up to $100 per day. She affords her habit by trading drugs and money for sex; she has not been tested for HIV or other sexually transmitted diseases in recent memory.
What is the most likely diagnosis?
Cocaine dependence. This patient exhibits the classic signs of addiction: she has tolerance for the drug (requires more to achieve the same effect), and experiences withdrawal symptoms without it. She has continued to use cocaine despite the negative consequences it brings, and she has been unable to bring herself to stop using despite many attempts. Smoking cocaine results in feelings of euphoria and heightened energy, while depression, hunger, and sleepiness are symptoms of withdrawal. The criteria for substance dependence can be remembered using the mnemonic WITHDrawIT:
What behavioral changes are associated with cocaine use?
Behavioral changes may include:
What physical changes are associated with cocaine use?
Physical changes may include:
What are the risks of cocaine use to the patient’s unborn child?
Since cocaine readily crosses the placenta and is metabolized slowly in fetuses, they can be exposed to significant levels of cocaine for long periods. Because of its vasoconstrictive properties, cocaine use increases the risk of fetal hypoxia and abruptio placentae.
In humans the most common consequences of cocaine abuse during pregnancy include premature birth, lower birth weight, respiratory distress, bowel infarctions, cerebral infarctions, reduced head circumference, and increased risk of seizures. Behaviorally, these newborns show an increased degree of tremulousness, crying, and irritability, and are overreactive to environmental stimuli. Within a month of birth these behaviors recover dramatically, but never to normal levels. It is important to remember that cocaine can be found in breast milk up to 60 hours after the last use.
By Kristen Vierregger, University of Pennsylvania School of Medicine, Class of 2008; in association with Le TT, Schabelman E, Shivaram A, and Klein J, eds: First Aid Cases for the USMLE Step 2 CK. New York: McGraw-Hill, 2007.
Feb 24th
A 63-year-old postmenopausal woman is referred to the gynecologic clinic by her primary care physician for evaluation of genital pruritus of 1 months’ duration. She has a remote history of human papillomavirus infection. She denies changes in vaginal discharge or vaginal bleeding. She also denies constitutional symptoms or weight loss. On examination she is in no apparent distress and heart rate is 70/min, blood pressure is 100/58 mm Hg, and respiratory rate is 10/min. Genital examination reveals an ulcerative white lesion approximately 1 cm in diameter on her labia majora. What is the most appropriate next step in management?
A. Obtain a biopsy of the lesion
B. Prescribe estrogen cream to be applied to area
C. Treat with acyclovir
D. Treat with cryotherapy
E. Treat with fluconazole
F. Treat with metronidazole
Feb 23rd
A third-year clerk on medical rounds notices that a large majority of his patients have either hypertension or congestive heart failure. He realizes that in treating both of these conditions, one class of drugs is commonly used.
What class of drugs is commonly used for these two conditions? List examples of drugs within this class?
These two conditions are both treated with B-blockers. Some commonly used B-blockers include propranolol, metoprolol, atenolol, esmolol, and timolol, among others. These agents all have in common the ending “–olol.”
For what other conditions is this class of drugs useful?
B-Blockers can be used to treat hypertension by decreasing cardiac output and renin secretion. After myocardial infarction, B-blocker use has been shown to decrease mortality. For angina pectoris, B-blockers are helpful because they decrease both heart rate and contractility, leading to a decrease in oxygen demand. Finally, B-blockers such as timolol can be used in glaucoma to inhibit the secretion of aqueous humor.
What is the selectivity of this class of drugs?
Both selective and nonselective B-blockers exist. Nonselective B-blockers block both B1 and B2 receptors equally and include propranolol, timolol, and nadolol. B1-Selective blocking agents can be remembered with the mnemonic “A BEAM of B1-blockers,” and include Acebutolol, Betaxolol, Esmolol, Atenolol, and Metoprolol.
What are some of the toxicities associated with this class of drugs?
Toxicity of B-blockers is significant. Clinical signs of toxicity include impotence, sleep alterations, and bradycardia.
Which two specific patient populations should be monitored closely while receiving treatment with B-blockers?
Caution should be used when giving B-blockers to diabetics because they may mask the usual symptoms of hypoglycemia. In patients with asthma, there is a risk of exacerbation of bronchiolar constriction due to antagonism of B2 receptors.
By Rakesh Razdan Ahuja, class of 2010, Yale University School of Medicine; in association with Le TT, Takiar V, eds: First Aid Cases for the USMLE Step 1. New York: McGraw-Hill, 2009.
Feb 22nd
A 42-year-old man presented to his primary care physician several months ago with complaints of fatigue, loss of appetite, difficulty concentrating, decreased sleep, and feelings of worthlessness. He has been receiving pharmacologic treatment for these symptoms and has now begun to develop symptoms of urinary retention, blurred vision, constipation, and aggravation of his glaucoma. Which of the following drugs is this patient most likely taking?
A. Bupropion
B. Fluoxetine
C. Nortriptyline
D. Phenelzine
E. Trazodone
Feb 20th
Beginning in April 2009, the sponsors of the USMLE program agreed, in response to concerns about the spread of pandemic novel H1N1 influenza, to waive their fees for eligibility period extensions. This temporary fee waiver was intended to give examinees flexibility in scheduling examinations during the influenza outbreak.
…Therefore, applications for eligibility period extensions received after May 31, 2010 will require payment of the eligibility period extension fee. In addition, examinees will be subject to the eligibility period extension restrictions in place prior to April 2009 (i.e., examinees will be permitted only one, three-month eligibility period extension, contiguous with the original eligibility period). The fee and restrictions apply to both already registered examinees as well as examinees who will register in the future.