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Step 2 Wed – USMLERx Step 2CK Question #21223
Aug 4th
A 53-year-old woman with a history of polycystic kidney disease undergoes a renal transplant from a cadaveric donor. She experiences several bouts of acute rejection that are controlled by appropriate increases in immunosuppression during the first year posttransplant. During her fourth posttransplant year her creatinine is rising gradually. Transcutaneous biopsy reveals architectural distortion and sclerosis of the renal tubules. What is the most likely outcome of the patient’s condition?
A. Development of lymphoproliferative tumors requiring decreased immunosuppression
B. Gradual onset of renal failure and return to dialysis
C. Requirement of chronic antibiotic prophylaxis against urinary tract infection
D. Response to increased chronic immunosuppression
E. Response to a short course of high-dose steroids
Step 1 Casebook – 4 year old boy with seizures
Aug 3rd
A 4-year-old boy is brought to the emergency department after being seen shaking on the floor. He had been playing with a video game when the episode began. He has no prior history of seizures or neurologic disorders. The episode resolved after 2 minutes.
What is the most likely diagnosis for this patient?
Most likely, the patient had a grand mal seizure due to the rapidly flashing lights in the video game.
What is the most appropriate treatment for this condition?
Grand mal or tonic-clonic seizures can be treated with phenytoin, carbamazepine, or valproic acid. In addition, avoidance of triggers can help prevent future seizures.
What are the side effects of the drugs associated with treatment?
Phenytoin is known to cause a characteristic gingival hyperplasia as well as a syndrome resembling systemic lupus erythematosus. Carbamazepine is known to cause blood dyscrasias such as aplastic anemia and agranulocytosis. Valproic acid commonly causes gastrointestinal upset and rarely, fatal hepatotoxicity.
If the boy were in class answering a question and suddenly stopped for 30 seconds, then continued with his explanation, what would be the diagnosis and treatment?
This is a classic case of an absence seizure, which is seen in children, but not in adults. The condition can be treated with ethosuximide. This drug acts by blocking thalamic T-type calcium channels.
Which two commonly used seizure medications may cause Stevens-Johnson syndrome?
Stevens-Johnson syndrome is a severe and life-threatening condition of the skin and mucous membranes. Its etiology is thought to involve the formation of immune hypersensitivity complexes. The two seizure medications associated with it are lamotrigine and ethosuximide.
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.
FA Step 2 Casebook: 19-year-old man with substance abuse
Jul 29th
Case 16 – A 19-year-old man with substance abuse
A 19-year-old student is being evaluated at his student health center. The physician notes the young man is tachycardic at 101/min with a blood pressure of 145/93 mm Hg. His pupils are constricted and there is a fine tremor in his hands. The patient appears agitated and is sweating. The student says he is just anxious about upcoming final examinations, but when questioned further he becomes angry and belligerent. He finally admits that for the past 2 weeks he has been taking pills his roommate gave him in order to help him stay awake. He says they improve his concentration and allow him to get by on only a few hours of sleep. He has not been eating as much and says his clothes are fitting more loosely on him. He does not see a problem with this, saying many people in the dormitory do the same thing, and that he will stop taking the pills after his examinations are done. The rest of the physical examination is unremarkable. On mental status examination he is alert and oriented to person, place, and time. He is mildly uncooperative, and his speech is rapid. He describes his mood as “terrific,” but his affect is angry. He denies suicidal or homicidal ideation, perceptual disturbances, or delusions. He does not have a prior history of mental illness.
What is the most likely diagnosis?
Amphetamine intoxication. He admits to recent use of pills acquired from his roommate to help him study. Although it is not known exactly what kind of pills he has been taking, the illicit use of dextroamphetamines is a significant problem on college campuses. He exhibits many of the diagnostic criteria found in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR) for amphetamine intoxication: he has not been sleeping or eating regularly and there is evidence of recent weight loss; his pulse and blood pressure are elevated, his pupils are dilated, and a tremor is present. He also exhibits behavioral and psychological changes of euphoria, anxiety, tension, and anger. Abuse of stimulants may also result in symptoms of psychosis such as paranoid delusions.
What are the DSM-IV-TR criteria for substance abuse?
The criteria for substance abuse can be remembered using the mnemonic HARP:
- Hazardous use (eg, driving while intoxicated)
- Arrests (legal problems)
- Role failure (repeated work absences due to substance use)
- Persistent use despite consequences
Only one of these four criteria need be met during a 12-month period. Still, this patient does not meet the criteria for substance dependency. The criteria for substance dependence can be remembered using the mnemonic WITHDrawIT:
- Withdrawal
- Interest or important activities given up or reduced
- Tolerance
- Harm (physical and psychosocial) with continued use
- Desire to cut down or control use
- Intended time/amount of use exceeded
- Time spent obtaining/using the substance is increased
Three of these seven criteria must be met within a 12-month period to diagnose substance dependency.
What would happen if the patient suddenly stopped taking the pills?
Amphetamine withdrawal is characterized by fatigue, depression, nightmares, headache, profuse sweating, muscle cramps, and hunger. Withdrawal symptoms such as intense dysphoria usually peak in 2-4 days and resolve within 1 week.
Is treatment necessary for patients in amphetamine withdrawal?
Since amphetamine intoxication and withdrawal are generally self-limiting, no specific treatment is necessary. Benzodiazepines (eg, diazepam, lorazepam) can be used to treat agitation or anxiety, but have their own abuse potential. Therapeutic drugs to treat the withdrawal are not routinely used in clinical practice.
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.
Step 2 Wed – USMLERx Step 2CK Question #21018
Jul 28th
A 30-year-old woman presents to a primary care physician for a new patient visit. She reports recurrent episodes of pneumonia, bronchitis, and otitis over the past 4 years. Although her vaccinations were up to date, she developed tetanus following a foot laceration last year. Her lymph nodes and tonsils are enlarged. Laboratory testing reveals low IgG, IgA, and IgM levels. After referral to a hematologist, who rules out other acquired and genetic causes of her hypogammaglobulinemia, she is diagnosed with common variable immunodeficiency. This woman is at the highest risk of developing which of the following condition?
A. Cardiovascular disease
B. Lymphoma
C. Miscarriage
D. Renal disease
E. Splenic autoinfarction
Step 1 Casebook – A newborn boy with apparent birth defects
Jul 27th
A newborn boy is found to have an increased head circumference, macroglossia, an umbilical hernia, lethargy, and a hoarse cry. The mother has no significant past medical history, takes no medications, and received adequate prenatal care. His serum thyroxine (T4) concentration is ~50% that of normal infants.
What is the most likely diagnosis?
Congenital hypothyroidism (aka cretinism).
Lack of adequate treatment of this condition is likely to result in what long-term consequence?
Congenital hypothyroidism is the most common treatable cause of mental retardation. Children with the condition were once popularly known as cretins (from the French word Chrétien or Christ-like), as they were so profoundly mentally retarded as to be considered incapable of sinning.
What are the most common causes of this condition?
Eighty-five percent are sporadic and 15% are inherited. The most common causes are thyroid dysgenesis (ectopy, hypoplasia, or complete agenesis); disordered thyroid hormone synthesis, secretion, or transport; and iodine deficiency. The condition is also more common in places where goiter is endemic.
How might thyroid disease in the mother affect the developing fetus?
In mothers with autoimmune hypothyroidism, thyroid-stimulating hormone-receptor blocking antibodies can cross the placenta and affect the fetus’ thyroid function. This “transient congenital hypothyroidism” should resolve within 1–3 months, when maternal antibodies are cleared from the infant’s system. Hyperthyroid women are more likely to have difficulties conceiving and have higher rates of miscarriage. Hyperthyroidism must be controlled in pregnancy, as the risks of miscarriage and birth defects are much higher without treatment.
Which thyroid medications are safe in pregnancy?
Thyroid hormone replacements (such as levothyroxine) for hypothyroidism are safe in pregnancy, given that the medication is appropriately prescribed and consumed. Antithyroid drugs given to hyperthyroid mothers can cross the placenta. Propylthiouracil (PTU) is the drug of choice for treating hyperthyroidism in pregnancy, as its transplacental effects on the fetus are less severe. PTU is cleared from the infant’s system within a few days after birth. Methimazole readily crosses the placenta and should be avoided in pregnancy, as should medications with large quantities of iodine, such as amiodarone for cardiac arrhythmia.
FA Step 2 Casebook: 25-year-old man after a motor vehicle accident
Jul 22nd
Case 15 – A 25-year-old man after a motor vehicle accident
A 25-year-old man is brought to the emergency department by ambulance after a motor vehicle accident. The paramedics report that his vehicle, which was not equipped with airbags, hit a telephone pole at a speed of approximately 35 mph. His temperature is 37.0°C (98.6°F), heart rate is 91/min, respiratory rate is 13/min, and blood pressure is 116/78 mm Hg. He is alert and oriented to person and place, but does not recall the date or any of the events leading up to the accident. He also reports that he feels very dizzy whenever he looks up at the ceiling. Examination of the head and neck reveals slight enophthalmos of the left orbit with infraorbital and upper lip anesthesia.
What is the most likely diagnosis?
Orbital fracture. Blowout fractures are the result of blunt trauma to the globe with rapid expansion of the orbital contents and rupture through the bony floor. A blowout fracture can also be the result of a direct blow to the orbital rim.
What is the etiology of this condition?
Facial fractures secondary to motor vehicle and recreational accidents are more common in rural areas, whereas penetrating trauma and assault-related injuries are more common in urban populations. Domestic violence and abuse should always be considered as a possible cause of the injury.
What other symptoms are common in patients with this condition?
Diplopia on upward gaze suggests inferior rectus muscle entrapment, but the etiology may be multifactorial. Infraorbital anesthesia is the result of a contused infraorbital nerve and anesthesia of the maxillary teeth and upper lip is common. Rarely, patients demonstrate enophthalmos, or sunken globe, when a large section of the globe has ruptured. Occasionally, a step-off deformity can be palpated over the intraorbital rim, or subcutaneous emphysema results from fracture into a sinus or nasal antrum.
What tests and/or imaging tools could be used to confirm the diagnosis?
Plain films are useful in the diagnosis of blowout fractures. The “hanging teardrop” sign suggests orbital fat herniating into the maxillary sinus. Once a blowout fracture is suspected, a CT scan of the face with coronal sections can be used to determine the surface area of the broken orbital floor.
What is the most appropriate management for this patient?
All orbital fractures may have repair delayed for 1-2 weeks; however, opinions regarding surgical repair vary among providers. Antibiotics against sinus pathogens are recommended for patients with subcutaneous emphysema.
By Julie Katz, MD, Resident in Anatomic and Clinical Pathology, The Johns Hopkins Hospital; 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.
Step 2 Wed – USMLERx Step 2CK Question #23176
Jul 21st
A 30-year-old man has episodes of wheezing and shortness of breath two to three times per week. Approximately every 2 weeks he awakens at night due to cough and difficulties breathing. He reports having similar symptoms since he was a child, but believes that they are worsening somewhat now. His symptoms are worsened by cold air and exercise and are improved by rest. Which of the following is the most appropriate treatment?
A. Daily high-dose inhaled corticosteroid and ?-agonist when needed
B. Daily high-dose inhaled corticosteroid with oral steroids for exacerbations and short-acting ?-agonist when needed
C. Daily low-dose inhaled corticosteroid and short-acting ?-agonist when needed
D. Daily oral steroids and long-acting ?-agonist
E. Short-acting ?-agonist when needed
Step 1 Casebook – 56-year-old man with a productive cough
Jul 20th
A 56-year-old homeless man with a history of alcohol abuse is found unconscious on a street corner. He is brought into the emergency department for monitoring. He is found to have a temperature of 38.9°C (102°F). X-ray of the chest is significant for pleural effusion, empyema, and cavitation of his right upper lobe. As he regains consciousness, he complains of chills and begins to cough up thick, bloody sputum. When stained, the sputum reveals gram-negative rods.
What is the most likely diagnosis?
Pneumonia secondary to infection with Klebsiella pneumoniae.
What are the characteristics of the causative organism?
Klebsiella pneumoniae is a gram-negative rod with a prominent polysaccharide capsule. This capsule helps protect it from host defenses such as phagocytosis and complement activity. On its surface, it has an O antigen, which is a lipopolysaccharide, and a K antigen, which is associated with the capsule. It also has adhesins so it can bind to host cells. It is part of the normal gastrointestinal (GI) flora in many people.
How does this patient’s infection usually present and which populations are most at risk?
Pneumonia caused by Klebsiella pneumoniae commonly presents with high fever, chills, flu-like symptoms, and a productive cough. The sputum is often described as being like currant jelly because it is thick, bloody, and mucoid. The pneumonia is typically a lobar one with necrosis and the formation of cavitary lesions in the affected lobe. There are usually signs of abscess formation, empyema, pleural adhesions, and pleural effusions on x-ray. Because this bacterium is often part of the normal GI flora, pneumonia is often secondary to aspiration. As a result, the susceptible populations are those with a history of loss of consciousness, such as alcoholics or stroke victims. It is also more common in those with diabetes and chronic obstructive pulmonary disease.
What other infections are most commonly seen with this organism?
K. pneumoniae is a common cause of nosocomial infections such as urinary tract infections (especially in those with a Foley catheter), thrombophlebitis, sepsis, liver abscesses, and meningitis.
What is the most appropriate treatment for this condition?
K. pneumoniae is resistant to various antibiotics via a plasmid-mediated mechanism. Antibiotics that typically work are the third-generation cephalosporins, carbapenems, aminoglycosides, and quinolones. However, in Klebsiella pneumonia, mortality reaches 50%, even with antibiotics.
By Christina L. Shenvi, PhD, class of 2009, 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.
Q&A Monday – USMLERx Step 1 Question #1005
Jul 19th
A 56-year-old obese man comes to the emergency department because of crushing chest pain that has been present for 3 hours. The pain radiates to his left arm and neck. He also complains of nausea. On physical examination, the patient is found to be sweating and his blood pressure is 164/122 mm Hg. Laboratory analysis reveals that his cardiac enzyme levels are elevated. His ECG is abnormal with ST-segment depression. Which of the following is the pathology underlying the correct diagnosis?
A. Coronary artery vasospasm caused by cigarettes and cocaine
B. Complete occlusion of the coronary arteries by a mural thrombus
C. Increased cardiac demand with coronary arteries that are greater than 75% occluded
D. Ischemic necrosis of 30% of the ventricular wall
E. Ischemic necrosis of 70% of the venricular wall
Conquer those Multimedia Questions on Step 1 and Step 2 CK!
Jul 15th
Need help with the multimedia questions on the USMLE Step 1 and Step 2 CK exams? The First Aid Team has you covered! Two of the topics that are easily tested in the multimedia format are heart sounds and EKG tracings. Both of those areas can be intimidating, but with the help of the Blaufuss Medical Multimedia Laboratories you can review and test your knowledge and become familiar with the way in which material can be presented, helping to keep you calm and collected on exam day. Check out their Cardiac Examination/Heart Sounds and Electrocardiogram/Arrythmia tutorials and Quizzes HERE.
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