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* NBME 15 Question review.
 #726998  
  fa2013ismylife - 03/25/13 18:52
 
  Need some help people, if you can help answer any of these I would be most grateful.




A 50-year-old man comes to the physician because of a 2-week history of progressive shortness of breath while climbing stairs to his office every morning. He reports no other problems, but he is concerned because his father had a major myocardial infarction at the age of 52 years. His pulse is 110/min and regular, respirations are 16/min, and blood pressure is 135/95 mm Hg. The lungs are clear to auscultation. Cardiac examination shows normal heart sounds with a physiologic split of S2. Stress echocardiography shows hypokinesis of the posterior left ventricle with increasing activity levels. Which of the following is the most likely cause of the posterior left ventricular findings in this patient?

A
)
Disruption of the sympathetic nerves to the left ventricle

B
)
Extravascular compression of the coronary arteries

C
)
Increased left ventricular end-diastolic pressure

D
)
Increased myocardial oxygen consumption

E
)
Stenosis of the right coronary artery




A 75-year-old woman comes to the physician because of a 3-month history of an enlarging lesion on her face. Physical examination shows a 1.5-cm, brown-black, mottled, scaly lesion with irregular borders. Microscopic examination of a biopsy specimen of the lesion shows atypical melanocytes spread along the basilar layer of the epidermis. Which of the following is the most likely cause of these findings?

A
)
Acanthosis nigricans

B
)
Actinic keratosis

C
)
Compound nevus

D
)
Lentigo maligna

E
)
Seborrheic keratosis





A 13-year-old boy is scheduled to receive chemotherapy for a leukemia that has the histologic features of malignant lymphocytes. This neoplasm is further typed for cell surface and intracellular markers specific for lymphocyte subsets. The neoplastic cells do not express the following markers: CD4, CD8, surface IgM, surface IgG, cytoplasmic IgM and μ-heavy chain, cytoplasmic IgG, and γ-heavy chain. The leukemic cells express class I MHC molecules and show rearrangement of the T-lymphocyte receptor β-chain gene D and J segments. Which of the following is the normal counterpart of these malignant lymphocytes?

A
)
Activated cytolytic effector T lymphocytes in the circulation

B
)
Mature IgM-secreting B lymphocytes in the lymph node

C
)
Mature immunoglobulin-secreting plasma cells in the lymph node

D
)
Pre-B lymphocyte progenitor of mature B lymphocytes in the bone marrow

E
)
T-lymphocyte thymocytes localized to the thymic cortex




A 70-year-old man has a 4-month history of weight loss, abdominal pain, and diarrhea. Stool analysis shows increased excretion of neutral fat and muscle fiber. A d-xylose test for carbohydrate absorption shows no abnormalities. Examination of tissue obtained on intestinal biopsy shows no abnormalities. This patient is most likely to respond favorably to administration of which of the following agents?

A
)
Antibiotics

B
)
Azathioprine

C
)
Intrinsic factor

D
)
Pancreatic enzymes

E
)
Prednisone






A 20-year-old woman comes to the physician because her menstrual period is 1 week late. Menses had occurred at regular 28-day intervals. She had unprotected sexual intercourse with her boyfriend 20 days ago. A urine pregnancy test result is positive. Which of the following best describes the stage of development of the embryo at this time?

A
)
The cytotrophoblast is present, but the syncytiotrophoblast has not yet formed

B
)
Gastrulation is complete, but there are only two germ layers

C
)
The neural plate is present, but the neural tube is not yet complete

D
)
Placental development is complete, but the embryo is resistant to teratogens

E
)
The sclerotome cells have begun migrating, but the somites have not yet formed





A 5-year-old boy is stung on his foot by a bee. Within 30 minutes the local area is edematous. The extravascular accumulation of fluid is most directly related to which of the following?

A
)
Demargination of leukocytes

B
)
Fibrin thrombi

C
)
Gap formation between endothelial cells

D
)
Vasoconstriction

E
)
Vasodilation







The vaccine against diphtheria confers protective immunity by inducing the formation of antibodies against a preparation composed of which of the following?

A
)
Killed bacterial cells

B
)
Live attenuated bacterial cells

C
)
Purified bacterial peptidoglycan

D
)
Purified capsular polysaccharide

E
)
Purified inactivated toxin








A 2-month-old girl is brought to the physician for a follow-up examination 2 days after a complete blood count was found to be abnormal. Her blood group is A, Rh-positive. She was born at term to a healthy 23-year-old woman whose blood group is O, Rh-positive. Birth weight was 3890 g (8 lb 9 oz). Pregnancy and delivery were uncomplicated. The patient has been active and feeding well. Her temperature is 37.6C (99.7F), pulse is 120/min, and respirations are 30/min. Physical examination shows no abnormalities. Laboratory studies done since birth are shown.





Patient Age
24 Hours 1 Week 1 Month
Hemoglobin (g/dL) (N=11−15) 16.9 15.7 12.7
Hematocrit (%) (N=28−45) 51 49 39
Leukocyte count (/mm3) (N=5000−19,500) 17,200 15,600 12,900
Segmented neutrophils 4% 3% 5%
Eosinophils 4% 4% 2%
Basophils 4% 2% 1%
Lymphocytes 69% 73% 77%
Monocytes 19% 18% 15%
Platelet count (/mm3) (N=150,000−400,000) 185,000 198,000 205,000


Which of the following is the most likely diagnosis?

A
)
Alloimmune hemolytic disease of the newborn

B
)
Congenital cytomegalovirus infection

C
)
Congenital neutropenia

D
)
DiGeorge syndrome

E
)
Severe combined immunodeficiency



A 50-year-old man comes to the emergency department because of a 2-week history of progressive shortness of breath. His pulse is 90/min, respirations are 26/min, and blood pressure is 120/80 mm Hg. Physical examination shows no other abnormalities. Laboratory studies show:



Arterial Pco2 30 mm Hg
Arterial Po2 96 mm Hg
Arterial O2 content 12 vol% (N=17%21%)
Mixed venous Po2 36 mm Hg
Mixed venous O2 content 8 vol% (N=10%16%)


Which of the following is the most likely explanation for these findings?

A
)
Anemia

B
)
Drug-induced alveolar hypoventilation

C
)
Residence at a high altitude

D
)
Severe regional mismatching of alveolar ventilation and pulmonary capillary perfusion

E
)
Voluntary hyperventilation





An 18-year-old man is brought to the physician by his father for a sports physical examination. He is a defensive end on his high school's football team and a champion wrestler. After his father leaves the examining room, the patient tells the physician that he is embarrassed because of enlarged breasts; he is worried that his classmates will make fun of him. He is extremely muscular, and there is no evidence of obesity. He is 173 cm (5 ft 8 in) tall and weighs 86 kg (190 lb); BMI is 29 kg/m2. His sexual development is Tanner stage 5. Physical examination shows 2-cm soft mounds of tissue beneath the areola bilaterally. Which of the following is the most appropriate next step by the physician?

A
)
Reassurance

B
)
Inquiry about a history of anabolic steroid use

C
)
Measurement of serum testosterone concentration

D
)
Mammography to rule out breast cancer

E
)
Referral for a breast reduction operation





A study is conducted of patients with restrictive airway disease who have BMIs above normal. Results show a significant correlation (r = 0.25) between body fat and lung capacity. Which of the following is the most accurate conclusion based on these data?

A
)
Increased body fat is associated with higher lung capacity

B
)
Increased body fat is associated with lower lung capacity

C
)
Twenty-five percent of individuals with increased body fat have a higher lung capacity

D
)
Twenty-five percent of individuals with increased body fat have a lower lung capacity

E
)
No relation exists between body fat and lung capacity




A 6-year-old boy is brought to the physician by his mother because of a 3-month history of pubic and axillary hair growth. On previous visits, he has been at the 50th percentile for height and weight. Pubic and axillary hair development is Tanner stage 2. Physical examination shows mild enlargement of the testes. If left untreated, which of the following combinations would best describe the likely course of growth in this patient?





Height Percentile

1 Year From Now As an Adult

A
)




25th 25th

B
)




25th 75th

C
)




50th 25th

D
)




50th 75th

E
)




75th 25th

F
)




75th 75th





A 45-year-old woman (III,7) comes to the physician for a routine health maintenance examination. Several people in her family, including her son (IV,3), have hereditary telangiectasia. A pedigree is shown. Physical examination and full medical evaluation show no abnormalities. Which of the following best explains the reason for this patient's health?

A
)
Gonadal mosaicism

B
)
Incomplete penetrance

C
)
Nonpaternity

D
)
Somatic mosaicism

E
)
Variable expressivity
Inline image 1


A 4-year-old boy with a karyotype of 47,XY+21 develops pancytopenia, lethargy, numerous bruises, pallor, and fever. Subsequent examination of the bone marrow is most likely to show which of the following?

A
)
Aplasia

B
)
Excess lymphoblasts

C
)
Megaloblastosis

D
)
Parvovirus inclusions

E
)
Ringed sideroblasts




A 40-year-old woman with breast cancer is brought to the physician because of a 1-week history of progressive loss of peripheral vision to the left in both eyes. On examination of each eye, she is unable to count fingers or detect finger movements on the left. An MRI of the brain is most likely to show a metastatic tumor in which of the following locations?

A
)
Occipital lobe

B
)
Optic chiasm

C
)
Optic nerve

D
)
Parietal lobe

E
)
Temporal lobe




A 13-year-old girl is brought to the physician by her mother because of a 5-month history of behavioral problems. The mother states that her daughter alternates from being sad and socially withdrawn to being extremely angry and aggressive. After further evaluation, a diagnosis of bipolar disorder is made. Treatment with valproic acid, which inhibits histone deacetylase, is started. This drug is most likely to affect which of the following processes in this patient?

A
)
mRNA splicing

B
)
Polyadenylation

C
)
Post-translational processing

D
)
Transcription

E
)
Translation


A 62-year-old man undergoes cystoscopy for investigation and removal of a suspected renal calculus. During the procedure, a cystoscope is inserted through the penis and into the bladder. Slit-like openings are then visualized near the lateral ends of the top of the trigone region of the bladder. Which of the following best describes these structures?

A
)
Ducts of the bulbourethral glands

B
)
Ejaculatory ducts

C
)
Internal urethral orifices

D
)
Ureteric orifices

E
)
Uvulae of the bladder



A 2-month-old male infant with a ventricular septal defect is brought to the physician because of poor weight gain and a 5-day history of rapid breathing and difficulty feeding. The diagnosis of congestive heart failure is made, and an operation to place a synthetic patch across the septal defect is planned. Compared with heart pressures prior to the operation, which of the following heart pressures are most likely 1 month after a successful operation?






Left Ventricular Pressure Right Ventricular Pressure Left Atrial Pressure

A
)





Increased increased no change

B
)





Increased decreased decreased

C
)





No change increased decreased

D
)





Decreased no change decreased

E
)





Decreased decreased increased



A 45-year-old man comes to the physician for a follow-up examination 2 weeks after beginning treatment with hydrochlorothiazide for hypertension. He says that he feels faint, light-headed, and dizzy when he gets out of bed and when he rises from a seated position too quickly. His pulse is 75/min, respirations are 12/min, and blood pressure is 130/85 mm Hg while supine. Physical examination shows no abnormalities. Which of the following sets of changes best characterizes changes in the cardiovascular system as this man goes from the supine to the standing position?






Carotid Sinus Cerebral

Venous Return Baroreceptor Activity Blood Flow

A
)





↑ ↑ ↑

B
)





↑ ↑ ↓

C
)





↑ ↓ ↑

D
)





↑ ↓ ↓

E
)





↓ ↑ ↑

F
)





↓ ↑ ↓

G
)





↓ ↓ ↑

H
)





↓ ↓ ↓



A 62-year-old man comes to the physician because of a productive cough, night sweats, and temperatures to 37.8C (100F) during the past 2 weeks. A PPD skin test is positive, but culture of sputum shows only normal flora after 2 days. A biopsy of an enlarged lymph node is done. The causal organisms are most likely to be present in which of the following cells in the specimen?

A
)
Epithelial cells

B
)
Fibroblasts

C
)
Macrophages

D
)
Neutrophils

E
)
T lymphocytes




A newborn delivered at 28 weeks' gestation is in severe respiratory distress. The immature alveoli of this newborn's lungs have a diminished ability to serve as sites of effective gas exchange. An increase in which of the following parameters best explains this finding?

A
)
Alveolar radii

B
)
Lung compliance

C
)
Lung elastic recoil

D
)
Pleural pressure

E
)
Surfactant secretion


A study is conducted to evaluate the effectiveness of cough medication in children. A total of 120 patients under the age of 12 years who have been diagnosed with a viral upper respiratory tract infection are randomly selected to receive dextromethorphan or no treatment. The participants were recruited from several emergency departments in an urban area. Parents complete a rating scale for their children's cough at baseline and 1 day after receiving dextromethorphan or nothing. The results show a statistically significant improvement in cough scores for patients receiving dextromethorphan (p=0.04) compared with children receiving no treatment. Which of the following is the most significant limitation to the internal validity of this study?

A
)
Lack of blinding between groups

B
)
Limited number of participants

C
)
Marginal statistical significance

D
)
Study location limited to only emergency departments

E
)
Subjective nature of the survey instrument





A 75-year-old woman is brought to the physician because of a 1-day history of fever and back pain. Her temperature is 39.5C (103.1F), pulse is 111/min, respirations are 32/min, and blood pressure is 115/79 mm Hg. Physical examination shows left-sided costovertebral angle tenderness. Laboratory studies show a leukocyte count of 17,000/mm3 (with 9% bands) and pyuria. Urine cultures grow Escherichia coli. It is determined that the patient's fever is partially due to interleukin-6 (IL-6), which was induced by the IL-1 produced during the immune response. Which of the following best describes the role of IκB in the nuclear factor-kappa B (NF-κB) signal transduction pathway from IL-1 binding to IL-6 induction in this patient?

A
)
Attaches to cytokine receptor

B
)
Facilitates proteolytic cleavage of NF-κB dimers

C
)
Phosphorylates NF-κB

D
)
Releases NF-κB after undergoing phosphorylation

E
)
Translocates to the nucleus after undergoing phosphorylation




A 22-year-old basketball player who uses cocaine recreationally suddenly develops severe shortness of breath after a routine scrimmage. Physical examination shows respirations of 25/min. The left lung field is hyperresonant and breath sounds are diminished. Which of the following is the most likely diagnosis?

A
)
Acute respiratory distress syndrome

B
)
Cor pulmonale

C
)
Flash pulmonary edema

D
)
Pleural effusion

E
)
Pneumothorax





Which of the following best explains why deoxygenated blood can carry more carbon dioxide for a given Pco2 than oxygenated blood?

A
)
Deoxyhemoglobin does not bind to 2,3-bisphosphoglycerate as efficiently as oxyhemoglobin

B
)
Deoxyhemoglobin has a lower capacity to form carbamino compounds than oxyhemoglobin

C
)
Deoxyhemoglobin has a lower pKa than oxyhemoglobin

D
)
Deoxyhemoglobin is a better buffer of hydrogen ions than oxyhemoglobin

E
)
Oxygen and carbon dioxide compete for the same binding site in hemoglobin

F
)
Oxyhemoglobin binds nitric oxide with a higher affinity than deoxyhemoglobin





An investigator wishes to test the hypothesis that a number of CD44 splice variants correlate with aggressive disease progression and risk of relapse in patients with Hodgkin disease, especially if the variant protein CD44v10 is expressed. The investigator plans to retrospectively screen archives of fresh frozen tissue and paraffin-embedded biopsy specimens from documented Hodgkin disease patients. Assuming the necessary reagents are available, which of the following methods would be the most effective in screening the archives for the variant protein?

A
)
Affinity column chromatography

B
)
Density gradient centrifugation

C
)
Immunohistochemistry

D
)
Northern blot

E
)
Polymerase chain reaction (PCR)

F
)
Reverse transcriptase PCR

G
)
Southern blot




A 3-year-old boy with chronic otitis media is scheduled to undergo bilateral myringotomies with placement of polyethylene tubes under general anesthesia. He is asleep after only three to five breaths of inhalational anesthetic delivered by face mask. Which of the following properties of the anesthetic is the most likely explanation for the rapid onset of action?

A
)
High blood solubility

B
)
High hepatic metabolism

C
)
High minimum alveolar concentration

D
)
Low blood solubility

E
)
Low hepatic metabolism

F
)
Low minimum alveolar concentration


A 4-day-old male newborn who was born at home is brought to the emergency department because of respiratory distress and cyanosis. The mother reports that she found him in his crib not breathing. He began to breathe again after she picked him up. Examination shows a narrow thorax. His ears have periauricular skin tags. He also has micrognathia, glossoptosis, a mandibular cleft, and a short palate. Tracheostomy relieves his respiratory distress. Defects such as these are consistent with altered development of which of the following pharyngeal arches?

A
)
First

B
)
Second

C
)
Third

D
)
Fourth

E
)
Sixth




An investigator is designing a study to compare a new behavioral program for attention-deficit/hyperactivity disorder (ADHD) with the standard behavioral modification program for this disorder. Because ADHD is more common among boys, girls and boys are randomized into the two treatment groups separately. Which of the following types of treatment allocation is most likely being used in this study?

A
)
Alternation

B
)
Open

C
)
Outcome-adapted

D
)
Simple random assignment

E
)
Stratification




A 22-year-old man is brought to the emergency department 30 minutes after he was hit by an automobile while crossing the street. The bumper of the automobile struck him on the lateral side of his left leg. On physical examination, he is unable to dorsiflex the left foot. Inversion and eversion of the foot are normal. Which of the following nerves is most likely damaged in this patient?

A
)
Deep fibular (peroneal)

B
)
Femoral

C
)
Lateral femoral cutaneous

D
)
Obturator

E
)
Tibial





A 43-year-old man comes to the physician because of progressive shortness of breath during the past year. He is a stockbroker and has had no environmental exposure to toxins. When asked about his smoking habits, he says he smoked marijuana in college and afterwards, until the age of 28 years. He has not smoked any substance since then. He was adopted as a child and does not know his family history. His respirations are 29/min. Diffuse wheezing is heard on auscultation of the chest. Abdominal examination shows mild hepatomegaly. Pulmonary function tests show a decreased FEV1 and decreased diffusing capacity. A chest x-ray shows hyperinflation consistent with air trapping mostly in the lung bases. A CT scan of the chest is shown. Which of the following is the most likely cause of these findings?

A
)
Asthma

B
)
Continuous marijuana use

C
)
Diffuse idiopathic interstitial fibrosis

D
)
History of smoking marijuana sprayed with a toxic herbicide

E
)
Inherited protease deficiency


Inline image 2


Vision screening is performed on 4000 people who are older than 65 years. Cataracts are found in 200. Which of the following best describes the annual incidence of cataracts in this population?

A
)
0.2%

B
)
0.5%

C
)
2%

D
)
5%

E
)
Unable to calculate due to insufficient data




A healthy 25-year-old man participates in a study of muscle function. The electrophysiologic observations made on a muscle biopsy specimen are shown. Via iontophoresis, 1 μM acetylcholine (ACh) was applied to the muscle surface. Extracellular Ca2+ concentration was decreased to prevent end-plate potentials from acting as a suprathreshold for muscle action potentials.





epp Amplitude mepp Amplitude Response (in mV) to ACh
(in mV) (in mV) (1 μM)
Normal muscle 10 1 1


epp=end-plate potential; mepp= miniature epp

Based on these findings, which of the following electrophysiologic characteristics is expected in a muscle biopsy specimen from a patient with acute botulism?






epp Amplitude mepp Amplitude Response (in mV) to ACh

(in mV) (in mV) (1 μM)

A
)





1 0.5 0.5

B
)





1 1 1

C
)





2 0.2 0.2

D
)





5 0.2 0.1

E
)





15 1 1



A 6-year-old boy with severe mental retardation and choreoathetosis is being evaluated for Lesch-Nyhan syndrome. Leukocytes are obtained for an assay of hypoxanthine-guanine phosphoribosyltransferase at saturating concentrations of phosphoribosylpyrophosphate and varying concentrations of guanine. Results of the data are shown.



Guanine Velocity (Patient)
(mM) μmoles/min
0.06 0.26
0.2 0.60
0.5 1.1
1.0 1.4
2.0 1.7
4.0 1.8
8.0 1.9
20 2.0
200 2.0


Which of the following is the approximate Michaelis constant [ Km] (in mM) for guanine in this patient?

A
)
< 0.06

B
)
0.2 to 0.5

C
)
0.5 to 1.0

D
)
1.0 to 2.0

E
)
8.0 to 20



A previously healthy 26-year-old woman comes to the physician because of a 1-day history of severe rectal pain with no bleeding. She takes no medications and does not smoke cigarettes or drink alcohol. She has been sexually active, and she and her partner use condoms inconsistently. A photograph of the rectal area is shown. Which of the following is the most likely diagnosis?

A
)
Anal carcinoma

B
)
Anal fissure

C
)
External hemorrhoid

D
)
Human papillomavirus infection

E
)
Skin tag
Inline image 3





A 64-year-old man comes to the physician because of a 2-month history of progressive shortness of breath with minimal activity. His temperature is 37C (98.6F), respirations are 30/min, and blood pressure is 125/80 mm Hg. Physical examination shows clubbing of the fingers. His total lung capacity is decreased. A chest x-ray shows a coarse reticular pattern. Which of the following is the most likely underlying cause of these findings?

A
)
Constriction of the terminal bronchioles

B
)
Destruction of the alveolar walls

C
)
Increased fibrosis in the interstitium

D
)
Increased mucus secretion in the bronchioles

E
)
Loss of elastic support to the walls of the bronchioles





A 55-year-old man comes to the physician because of a 2-month history of increasing difficulty swallowing and regurgitation of undigested food. He also has noticed unusual rumbling sounds in his voice that he feels originate in his neck. Physical examination shows halitosis. A videofluoroscopic swallowing study shows a 4-cm, posterior midline pouch protruding between the thyropharyngeus and cricopharyngeus portions of the inferior pharyngeal constrictor muscle. These muscles are most likely innervated by which of the following nerves?

A
)
Glossopharyngeal nerve

B
)
Hypoglossal nerve

C
)
Motor fibers from the vagus nerve

D
)
Parasympathetic fibers from the vagus nerve

E
)
Sympathetic fibers from the superior cervical ganglion



A 20-year-old competitive cyclist taking recombinant human erythropoietin has polycythemia. Which of the following is the most likely cause?

A
)
Early release of reticulocytes from bone marrow

B
)
Increased erythrocyte life span

C
)
Proliferation of bone marrow stem cells

D
)
Proliferation of erythroid precursors



A 6-year-old girl is brought to the physician for a follow-up examination. She has been receiving treatment with potassium citrate monohydrate since the diagnosis of renal tubular acidosis was made at the age of 2 years. Physical examination shows no abnormalities. Serum studies show:



Na+ 142 mEq/L
K+ 3.5 mEq/L
Cl 115 mEq/L
HCO3 18 mEq/L
Urea nitrogen 9 mg/dL
Creatinine 0.9 mg/dL


A defect in renal ammoniagenesis is suspected. Which of the following substrates is the most likely source of ammonia production in this patient?

A
)
Creatinine

B
)
Glutamine

C
)
Glycine

D
)
Leucine

E
)
Urea



A 35-year-old woman, gravida 1, para 1, comes to the physician because of a 2-month history of generalized weakness and fatigability that are significantly exacerbated by exercise. The symptoms began during her pregnancy. Physical examination shows diplopia. There is reduction in arm muscle strength with repetitive movement, but preservation of deep tendon reflexes. A therapeutic trial of oral pyridostigmine provides symptomatic relief. Serum studies will most likely show antibodies to which of the following proteins?

A
)
Acetylcholinesterase

B
)
Muscarinic acetylcholine receptor

C
)
Myeloperoxidase

D
)
Nicotinic acetylcholine receptor


A 2-year-old girl is brought to the emergency department 20 minutes after she accidently ingested insecticide. Her father reports that he was spraying his lawn and accidentally left the open bottle on the ground. His daughter walked over, picked up the bottle, and started to drink, but then she immediately threw down the bottle. She is in moderate respiratory distress. Her respirations are 18/min and shallow. Pulse oximetry on room air shows an oxygen saturation of 82%. Physical examination shows copious oral secretions. In addition to securing an airway, the most appropriate immediate step is administration of which of the following medications?

A
)
Atropine

B
)
Diphenhydramine

C
)
Physostigmine

D
)
Pralidoxime

E
)
Succinylcholine



Following a stroke, a 68-year-old man has a language problem. His speech is fluent but contains many grammatical errors, word substitutions, and neologisms. He is unable to repeat words after the examiner and is apparently unable to comprehend other verbal requests. Which of the following labeled sites on the photograph of the left hemisphere is most likely to be damaged?



A
)


B
)


C
)


D
)


E
)


F
)


G
)


H
)


I
)


J
)



A 30-year-old man is brought to the physician by his wife because of a 1-day history of irrational behavior and severe abdominal pain. He began treatment with trimethoprim-sulfamethoxazole for a urinary tract infection 3 days ago. His urine turned a light burgundy color during a similar episode 1 year ago. His mother and his maternal grandfather have had similar symptoms. He appears anxious and restless. His pulse is 96/min. Physical examination shows diaphoresis. Serum studies show increased concentrations of 5-aminolevulinic acid (δ-ALA) and porphobilinogen. The physician suspects that a mutant allele is causing decreased activity of an enzyme involved in heme biosynthesis. This enzyme is most likely which of the following?

A
)
δ-ALA dehydratase

B
)
δ-ALA synthase

C
)
Ferrochelatase

D
)
Porphobilinogen deaminase

E
)
Uroporphyrinogen decarboxylase



A 25-year-old woman with a history of rheumatic fever and mitral valve dysfunction comes to the physician because of a 2-week history of fever and fatigue. She underwent a root canal procedure 1 month ago, before which she had taken a single dose of amoxicillin. Her temperature is 38.4C (101.2F). A grade 4/6 blowing murmur is heard on auscultation under the left axilla. A photomicrograph of a Gram stain of the organism recovered from a blood culture specimen is shown. On blood agar plates, the organism shows alpha hemolysis. Which of the following is the most likely causal organism?

A
)
Enterococcus faecalis

B
)
Group A beta-hemolytic streptococci

C
)
Staphylococcus aureus

D
)
Streptococcus mitis

E
)
Streptococcus pneumoniae




A 56-year-old woman comes to the physician because of a 3-week history of progressive difficulty swallowing. When her symptoms began, she felt that bread and larger pieces of meat were getting stuck in her chest before passing through completely, but now she is having difficulty swallowing all foods and some liquids. Physical examination shows normal oral coordination and a nontender abdomen. An x-ray obtained after a barium swallow shows an irregular mass at the gastroesophageal junction. A photomicrograph of a biopsy specimen obtained via esophagogastroduodenoscopy is shown. Chronic infection with which of the following pathogens is the most likely cause of the histologic findings in this patient?

A
)
Clonorchis sinensis

B
)
Cytomegalovirus

C
)
Entamoeba histolytica

D
)
Helicobacter pylori

E
)
Mycobacterium tuberculosis





A 45-year-old man comes to the physician for an initial examination. He has not been examined by any physician during the past 30 years because he has not felt ill. He says that he feels well at this visit. He appears relaxed. Cardiac examination shows a grade 2/6, holosystolic murmur that is best heard at the left axillary line. Which of the following is the most likely cause of this finding?

A
)
Aortic regurgitation

B
)
Aortic stenosis

C
)
Mitral regurgitation

D
)
Mitral stenosis

E
)
Tricuspid regurgitation

F
)
Tricuspid stenosis



A 71-year-old woman comes to the physician for a follow-up examination. She has a 30-year history of type 2 diabetes mellitus currently treated with insulin. She is 160 cm (5 ft 3 in) tall and weighs 59 kg (130 lb); BMI is 23 kg/m2. Her blood pressure is 116/78 mm Hg. This patient is most likely to have an endogenous fasting serum insulin concentration (N=520 μU/mL) closest to which of the following?

A
)
1 μU/mL

B
)
10 μU/mL

C
)
20 μU/mL

D
)
40 μU/mL

E
)
80 μU/mL




A 22-year-old woman is found to be HIV positive after sexual contact with a partner with HIV infection. Combination therapy with lamivudine (3TC), ritonavir/lopinavir, and zidovudine (AZT) is initiated. Three months later, genomic typing shows that her HIV strain has become resistant to ritonavir/lopinavir. The cause of this resistance is most likely the acquisition of a mutation in a gene that is critical for which of the following viral processes?

A
)
Adsorption and penetration

B
)
Early protein synthesis

C
)
Genome integration

D
)
Late protein synthesis

E
)
Nucleic acid synthesis

F
)
Packaging and assembly

G
)
Protein processing

H
)
Release

I
)
Uncoating




A 43-year-old man with a 10-year history of alcoholism comes to the physician because of a change in skin color. The patient says that he has been taking two extra-strength acetaminophen tablets every 4 to 6 hours for the past 3 days for a severe headache. Physical examination shows jaundice. Laboratory studies show an increased prothrombin time and a markedly increased serum AST activity. Alteration in which of the following metabolites within hepatocytes is most likely associated with his illness?

A
)
Decreased glucuronide conjugates

B
)
Decreased glutathione

C
)
Decreased NAD+

D
)
Decreased NADH

E
)
Increased glucuronide conjugates

F
)
Increased glutathione

G
)
Increased NAD+

H
)
Increased NADH





A 25-year-old primigravid woman at 12 weeks' gestation comes to the physician 1 hour after she passed a small amount of tissue vaginally at home. Gross examination of this tissue shows an obvious fetus. Microscopic examination of tissue obtained via dilatation and curettage shows chorionic villi with focal edema and trophoblastic proliferation. Which of the following is the most likely diagnosis?

A
)
Choriocarcinoma

B
)
Complete hydatidiform mole

C
)
Partial hydatidiform mole

D
)
Placenta accreta

E
)
Placental site trophoblastic tumor


A 67-year-old man is brought to the physician because of a 2-day history of double vision and drooping of his left eyelid. He has no history of trauma to the eye. His vital signs are within normal limits. Physical examination shows ptosis of the left eyelid. When the eyelid is raised manually, the eye is fixed in the out position and the pupil is dilated. The visual acuity of the left eye is within normal limits. Which of the following is the most likely cause of these findings?

A
)
Aneurysm of the posterior communicating artery

B
)
Compression of the superior cervical ganglion

C
)
Damage to the trochlear nerve

D
)
Occlusion of the scleral venous sinus

E
)
Tumor of the optic nerve


A 2-month-old male infant is brought to the emergency department by his mother because of a 2-day history of generalized tonic-clonic seizures, myoclonus, and hiccuping. His mother says he has fed poorly and has been floppy since birth. Physical examination shows decreased deep tendon reflexes and hypotonia. A signaling defect in an inhibitory neurotransmitter is suspected. Which of the following neurotransmitter receptors most likely contains the defect?

A
)
Acetylcholine receptor

B
)
Aspartic acid receptor

C
)
Epinephrine receptor

D
)
Glutamate receptor

E
)
Glycine receptor



A 47-year-old man is admitted to the hospital for treatment of a myocardial infarction. On admission, pulse oximetry on 30% oxygen shows an oxygen saturation greater than or equal to 95%. Three hours later, the patient develops shortness of breath. Pulse oximetry now shows an oxygen saturation of 90%. Crackles are heard at the lung bases, and a grade 2/6 systolic murmur is heard. Arterial blood gas analysis on 30% oxygen shows:



pH 7.41
Pco2 36 mm Hg
Po2 60 mm Hg


Which of the following is the most likely cause of this patient's hypoxemia?

A
)
Decreased alveolar ventilation

B
)
Decreased erythrocyte transit time in pulmonary capillaries

C
)
Decreased lymphatic drainage

D
)
Increased permeability of pulmonary capillaries

E
)
Increased plasma colloid osmotic pressure

F
)
Increased pulmonary capillary pressure






 
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* Re:NBME 15 Question review.
#2859732
  dreddy - 03/25/13 19:05
 
  2. D
3. E
4. D
5. C
6. C
7. E
10. B
11. D
13. B
14. A
16. D
20. C
21. C
next time number your questions....
these i know are the right answers, i didnt miss them on the nbme
 
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* Re:NBME 15 Question review.
#2859733
  dreddy - 03/25/13 19:07
 
  lost count for the rest....number them next time so it will be easier to look at.  
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* Re:NBME 15 Question review.
#2859740
  fa2013ismylife - 03/25/13 19:15
 
  I will fix them right now sorry for the confusion  
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* Re:NBME 15 Question review.
#2859741
  fa2013ismylife - 03/25/13 19:16
 
  will create a new thread, please disregard this thread. Thanks Dreddy  
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* Re:NBME 15 Question review.
#2859742
  dreddy - 03/25/13 19:22
 
  post these in the thread called nbme 15 discussion  
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* Re:NBME 15 Question review.
#2859743
  antonella - 03/25/13 19:22
 
  A 50-year-old man comes to the physician because of a 2-week history of progressive shortness of breath while climbing stairs to his office every morning. He reports no other problems, but he is concerned because his father had a major myocardial infarction at the age of 52 years. His pulse is 110/min and regular, respirations are 16/min, and blood pressure is 135/95 mm Hg. The lungs are clear to auscultation. Cardiac examination shows normal heart sounds with a physiologic split of S2. Stress echocardiography shows hypokinesis of the posterior left ventricle with increasing activity levels. Which of the following is the most likely cause of the posterior left ventricular findings in this patient?

A
)
Disruption of the sympathetic nerves to the left ventricle

B
)
Extravascular compression of the coronary arteries

C
)
Increased left ventricular end-diastolic pressure

D
)
Increased myocardial oxygen consumption

E
)
Stenosis of the right coronary artery

There are two ways to answer this question..One is they are telling us posterior wall of LV and that is supply by RCA and if we do not know that ,we have an info saying that the lungs are clear and that means no pulmonary edema and that means this is not LVF ,but RVF and therefore involves the Right ventricle that is supply by RCA.
So RCA supply Right Ventricle and Posterior Wall of LV..
Answer is E -Stenosis of RCA
 
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