A 4-year-old boy is brought to the emergency department by his mother for severe right leg pain. The pain began suddenly 6 hours ago and has been unremitting. He has been well other than having a mild nonproductive cough and runny nose 1 week ago that resolved 2 days ago. The patient has a history of asthma and sickle cell disease, for which he takes hydroxyurea, penicillin, and an albuterol inhaler as needed. He has not had any prior surgeries. He is up to date on his vaccinations, including pneumococcal, influenza, and meningococcal vaccines. He lives with his parents and has 2 siblings, who are healthy. The patient’s temperature is 98.6°F (37.0°C), blood pressure is 98/56 mmHg, pulse is 140/min, and respirations are 22/min. Physical examination shows a tearful boy holding his right calf in pain. A cardiopulmonary examination is unremarkable. His abdomen is soft, nontender, and nondistended. His right calf is diffusely painful without focal tenderness. There is no overlying erythema in the affected extremity. Passive range of motion of his right hip, knee, and ankle are full. He refuses to participate in the gait exam. The results of serum laboratory results are shown below: Hemoglobin: 9.2 g/dL Platelet count: 160,000/mm^3 Reticulocyte count: 5% Erythrocyte sedimentation rate (ESR): 10 mm/h Radiographs of the right tibia, fibula, and ankle are unremarkable. Which of the following is most likely to be decreased in this patient?

A 58-year-old man presents to the emergency department with acute onset vision loss in his left eye. The patient is a university professor. Approximately 30 minutes ago, he was delivering a lecture when he suddenly noticed decreased vision in his left eye. The decrease in vision happened over a period of a few seconds and was not associated with pain. The patient’s past medical history is significant for hypertension, hypercholesterolemia, diabetes, and bilateral osteoarthritis of the knees. His medications include atorvastatin, lisinopril, metformin, and semaglutide. He is unsure of his family history but notes his mother is of Ashkenazi Jewish descent. He quit smoking 10 years ago, but previously smoked half a pack of cigarettes per day for 30 years. His temperature is 98.6°F (37.0°C), blood pressure is 132/70 mmHg, pulse is 87/min, respirations are 16/min, and O2 saturation is 99% on room air. His BMI is 33 kg/m^2. Eye exam reveals 20/20 vision in the right eye and he is only able to count fingers at 3 feet in the left eye. The intraocular pressure is 14 mmHg in both eyes (normal 12-21 mmHg). Indirect ophthalmoscopy reveals the findings shown in Figure A. Which of the following is the most likely diagnosis in this patient?

Researchers are studying a common pathogenic bacterium. They isolate the organism of interest on a culture medium that contains Mueller-Hinton agar, 5% chocolate sheep blood, vancomycin, polymyxin, nystatin, and trimethoprim. Which of the following is an infection most commonly associated with the organisms that grow in this culture medium?

A 28-year-old woman presents to the emergency department with sudden-onset, severe pelvic pain. The pain began 1 hour ago and there were no apparent inciting factors. The patient had been feeling well otherwise, without fever, chills, or vaginal bleeding. Since the pain began, she has experienced waves of nausea with some vomiting. She has a history of exercise-induced asthma for which she uses an albuterol inhaler. Six months ago, her gynecologist discovered a 5-cm cystic mass on her left ovary. The mass was round, anechoic in appearance, and had no evidence of internal flow on Doppler ultrasonography. The gynecologist recommended surveillance of the cyst. The patient has no surgical history. She does not smoke cigarettes, drinks alcohol socially, and does not use illicit drugs. She works as a teacher. She is sexually active with 3 men and intermittently uses condoms. The patient's temperature is 100.1°F (37.8°C), blood pressure is 120/80 mmHg, pulse is 110/min, and respirations are 20/min. Physical examination reveals a woman in acute pain. Cardiac auscultation reveals a normal S1 and S2. Her lung fields are clear bilaterally. Her abdomen is soft and nondistended. There is pain on deep palpation of her lower abdomen but no masses are palpated. A transabdominal ultrasound is obtained, showing a diffusely enlarged left ovary. A urine beta-human chorionic gonadotropin (beta-hCG) test is negative. Which of the following is the most likely diagnosis?

A 48-year-old woman presents to the physician with poorly controlled blood pressure. She measures her blood pressures at home and they have intermittently been in the 170-190/80-90 mmHg range. The patient endorses intermittent palpitations and diaphoresis. She denies fever, cough, or dysuria. The patient has a history of hypertension, hyperlipidemia, and asthma. Her medications consist of lisinopril, amlodipine, hydrochlorothiazide, rosuvastatin, and an as-needed albuterol inhaler. She received a left anterior cruciate ligament reconstruction 10 years ago. She has a 40-pack-year smoking history but quit 5 years ago. She does not drink alcohol or use illicit drugs. The patient's temperature is 98.6°F (37.0°C), blood pressure is 110/70 mmHg, pulse is 80/min, and respirations are 16/min. Cardiopulmonary exam discloses a normal S1 and S2 without murmurs and clear bilateral lung fields. Her abdomen is soft and nontender. Serum and urine metanephrines are elevated. The patient is diagnosed with an isolated, benign adrenal tumor. Despite recommendations for curative surgical treatment and its risks and benefits, the patient states that her relative died from a surgical complication and she would like to use an herbal remedy only, that she read about. Which of the following is the most appropriate next step by the physician?

A 71-year-old woman presents to her primary care physician for her yearly physical exam. Since her last visit, she sustained a distal radius fracture from a ground-level fall that has healed without complication. At the time, it was recommended that she undergo a bone density scan and she is interested in the results of that study today. Her past medical history is significant for hypertension but she is not currently taking any medications. Her temperature is 98.6°F (37°C), blood pressure is 152/91 mmHg, pulse is 73/min, and respirations are 13/min. Her blood pressure during her previous visit was also elevated in this range. A physical exam is unrevealing with no murmurs, rubs, or gallops appreciated. Her physician lets her know that the Z-score for her bone mineral density is -2.9. Which of the following medications would be most effective in addressing both her bone mineral density and her elevated blood pressure?

An 81-year-old man with a history of papillary thyroid carcinoma is admitted to the hospital in order to proceed with a surgical thyroidectomy. His past medical history is significant for hypertension, diabetes, and thyroid carcinoma which was diagnosed by fine needle aspiration. His temperature is 98.6°F (37°C), blood pressure is 145/91 mmHg, pulse is 91/min, and respirations are 12/min. Physical exam demonstrates a nodular thyroid gland but no other significant findings. During the process of consent, the risks and benefits of the surgery are discussed. Standard risks of surgery such as infection, bleeding, and damage to surrounding structures are presented. The patient asks about what symptom he would experience if nerve damage was sustained during the surgery. Which of the following would be a result of the most common nerve complication of this surgery?

A scientist is studying the behavior of a novel hormone receptor in humans. The hormone is found to circulate systemically in the bloodstream and results in pleomorphic effects in different organ systems. She isolates cells that express the hormone receptor and uses differential centrifugation techniques in order to fractionate the membranes present in the cell. She finds that the hormone receptor is expressed in both the cytosolic and nuclear fractions of the homogenate but is not present on the plasma membrane or low-density membrane fractions of the homogenate. She uses formaldehyde to crosslink the receptor in the nuclear fraction of the homogenate and found that the receptor is bound to DNA. Which of the following hormones would most likely bind to the receptor described in this case?

A 6-year-old boy is brought to the emergency department by his parents for increasing abdominal pain. The pain began 3 days ago and has become progressively worse. It is associated with nausea and vomiting. He had some mild watery diarrhea and low-grade fevers starting 1 week ago that resolved without further treatment. Over the past 5 days, his parents note that he has been running to the bathroom more frequently than usual. He has no known medical problems and takes a pediatric multivitamin. He has no prior surgeries. He lives at home with both parents and an older sister and they have a pet cat. The patient's temperature is 98.6°F (37.0°C), 100/64 mmHg, pulse is 122/min, and respirations are 38/min. Physical examination reveals an ill-appearing boy with rapid and deep respirations. Cardiac auscultation reveals a normal S1 and S2 without any murmurs. His oral mucosa is dry and there is no axillary moisture. Laboratory results are shown below: Fingerstick blood glucose: 600 mg/dL Urine beta-hydroxybutyrate: positive Which of the following enzymes is most likely to have increased activity as a result of this patient's condition?

A 78-year-old woman is brought to the emergency department by ambulance for altered mental status. She is a resident at a skilled nursing facility, where she was noted to have lower abdominal discomfort 3 days ago. She had 1 episode of urinary incontinence on each of the last 2 nights. This morning, she was found to be disoriented to place and time. The patient has a history of diabetes mellitus, hypertension, and congestive heart failure for which she takes metformin, insulin, lisinopril, metoprolol, and spironolactone. She also had a stroke 3 years ago that left her with residual dysarthria. She received a left total knee arthroplasty 20 days ago. She is up to date on her vaccinations, including herpes zoster. She has a 30-pack-year smoking history and quit 15 years ago. She does not drink alcohol. She has a history of intravenous drug use. She is a retired librarian. The patient's temperature is 103.6°F (39.8°C), blood pressure is 90/56 mmHg, pulse is 120/min, and respirations are 22/min. Physical examination reveals an ill-appearing woman. She is oriented only to person. Cardiac exam reveals a normal S1 and S2 with an S4 gallop. There are no murmurs or rubs. Bronchial breath sounds are heard bilaterally. Her abdomen is soft and nondistended. There is right costovertebral angle tenderness. Which of the following is the most likely cause of this patient's condition?

An investigator is studying the relationship between rotavirus vaccination and intussusception in children under 4 years of age. In an observational study, 200 participants with intussusception are matched by age and sex with 200 participants without intussusception. The rotavirus vaccination status of all participants is known. Among the participants with intussusception, 15 had received rotavirus vaccination. Among those without intussusception, 5 had received rotavirus vaccination. Which of the following would be the most appropriate statistical measure to report the relationship between rotavirus vaccination and intussusception in this study?

A 54-year-old man presents to primary care with a burning sensation in his feet. He began experiencing these symptoms 2 weeks ago and complains that the burning is constant. There was no inciting event or trauma. He has also had numbness and tingling in his fingertips and feet for the past 2 years. He denies cognitive, mood, or sleep changes. He has a history of poorly-controlled type 2 diabetes for which he takes metformin and glipizide. The patient’s temperature is 98.4°F (36.9°C), blood pressure is 144/82 mmHg, pulse is 90/min, and respirations are 18/min. On examination, there is decreased 2-point discrimination in his hands and feet bilaterally. What is the most appropriate treatment for this patient's symptoms?

A 40-year-old woman presents to her primary care provider for several months of headaches. The patient states that she has no significant medical or surgical history. She is also nulliparous and is sexually active with her husband. However, she does note that her periods have been abnormally late for the past few months. Her temperature is 98.6°F (37°C), blood pressure is 124/75 mmHg, pulse is 70/min, and respirations are 14/min. The physical exam is unremarkable. Her urine pregnancy test is negative. Figure A is her magnetic resonance imaging (MRI) results. Which of the following lab values would be found in this patient?

A 2-week-old newborn girl is brought to the pediatrician for failure to thrive. Her mother says that she feeds poorly, latching on for only 5 minutes at a time. She is producing 3-4 wet diapers a day. She was born at 38-weeks gestational age with a birth weight of 3.5 kg. She received vitamin K and topical erythromycin at birth. The perinatal course was uncomplicated. The patient’s temperature is 98.4°F (36.9°C), blood pressure is 68/44 mmHg, pulse is 120/min, and respirations are 45/min. She weighs 3.1 kg. Exam reveals a 3/6 harsh, holosystolic murmur at the left lower sternal border. Which of the following additional findings is most likely present?

A 32-year-old woman presents to her primary care physician with anxiety and insomnia. Her symptoms started 3 weeks ago. She states that she feels constantly “on edge” and is unable to get any work done. She denies any palpitations, tremors, or diaphoresis. She has no medical history and takes no medications. Her mother died from breast cancer 2 months ago. The patient was fired from her job last week for falling asleep during meetings and failing to meet project deadlines. The patient’s temperature is 98.2°F (36.8°C), blood pressure is 114/76 mmHg, pulse is 70/min, and respirations are 16/min. Exam reveals an anxious-appearing woman with no psychomotor agitation or retardation. She describes her mood as sad, but only when thinking about her mother. There is no suicidal or homicidal ideation. What is the most appropriate diagnosis?

A 73-year-old man presents to the emergency department with complaints of shortness of breath and right-sided chest pain over the past 2 weeks. Upon further questioning, he mentions that he has lost over 20 pounds over the past 2 months despite maintaining his usual diet. His past medical history is significant for hypertension and diabetes. He quit smoking 10 years ago, but has a 50-pack year history, and used to work in construction for the Navy before retiring. His temperature is 99.5°F (37.5°C), blood pressure is 145/85 mmHg, pulse is 101/min, and respirations are 19/min. On examination, there is dullness to percussion on the right side of his chest. A chest radiograph is shown in Figure A. A thoracentesis is performed which drains dark, red pleural fluid. Fluid analysis results are as below. Pleural pH: 7.35 Serum LDH (U/L): 200 Serum total protein (g/L): 75 Pleural fluid LDH (U/L): 127 Pleural fluid total protein (g/L): 53 RBCs: 150,000 cells per uL Which of the following will most likely be found on biopsy?

A 65-year-old man presents with a complaint of increased difficulty with buttoning his shirts over the past 6 months. His hands have been shaking when he tries to do things like put on clothing or reach for objects. This tremor is not present when he is relaxed. His father had similar symptoms when he was 50-years-old. The patient is an executive who continues to lead a multinational corporation. His wife says his frequency of alcohol use has increased over the past year. The patient’s temperature is 98.2°F (36.8°C), blood pressure is 124/76 mmHg, pulse is 80/min and regular, and respirations are 16/min. When asked to hold his hands outstretched, there is an 8-Hz tremor of both hands. There is no tremor at rest, ataxia, or dysdiadochokinesia. Gait analysis reveals a slow cadence, dynamic imbalance, and gait asymmetry, in addition to narrow-based turns. He scores 27/30 on the mini-mental state exam (MMSE). What is the mechanism of action of the most appropriate treatment for this patient’s condition?

A 52-year-old woman presents to her primary care physician with a 2-week history of a worsening rash. She says that about 1-month ago she was hiking in the woods when she tripped and fell into a bush. She sustained some scratches on her arms and felt a sting that she thought might have been an insect bite. The scratches healed quickly, but 2 weeks later, she noticed a red bump near her wrist that has continued to grow in size and ulcerate over time. She became concerned when she started noticing other bumps developing on her arm and decided to seek evaluation. A picture of the rash is shown in Figure A. Which of the following is the most appropriate treatment for this disease?

A 3-month-old boy is brought to an urgent care clinic because his parents are concerned about him being "cross-eyed". He was born at home to a G1P1 mother and has not previously been medically evaluated or vaccinated. His parents say that they have not noticed any other deficits in development and that he has been feeding well and gaining weight since birth. On presentation, he does not have the red reflex bilaterally, and further examination reveals clouding of the lens. All other physical exam findings are normal, and he is at an appropriate height and weight for his age. Which of the following enzymes is most likely defective in this patient?

A 71-year-old man presents to his primary care physician for his annual visit. He says that he doesn't like the metformin medication that he was prescribed during his last visit and has been taking it roughly 2 times a week rather than every day as prescribed. His past medical history is significant for type 2 diabetes, and his last hemoglobin A1c was 8.7%. His only medication is metformin, and he has no known drug allergies. Which of the following is the most appropriate way to address this patient's medication concerns?

A 32-year-old woman presents to her primary care physician with a 1-week history of severe fatigue. She says that about 2 weeks ago, she experienced mild upper respiratory symptoms that resolved on their own. Since then, she started feeling fatigued and experiencing pain in her bilateral hands and wrists. She initially dismissed these symptoms as part of getting older; however, she became more concerned as the fatigue has been getting worse over time and now interferes with her daily activities. She recently returned from a safari vacation in Kenya, but has not had any other travels and does not recall being ill while on vacation. She lives in upstate New York and works as a park ranger. Her past medical history is significant for sickle cell anemia. On physical exam, her temperature is 99°F (37.2°C), blood pressure is 110/71 mmHg, pulse is 114/min, and respirations are 14/min. She is found to have mild swelling and erythema in her metacarpal-phalangeal joints bilaterally. A complete blood count is performed with the following results: Hemoglobin: 6.2 g/dL Leukocyte count: 1,420/mm^3 Platelet count: 28,000/mm^3 Which of the following is the most likely cause of this patient's symptoms?

A 24-year-old man is brought to the emergency department by ambulance after he was involved in a fight. During the trauma survey, he is found to have a gunshot wound to his neck. He is admitted for emergency surgery, at which time he is found to have a laceration to a major nerve. During his recovery, the patient asks about the function of the damaged nerve and is told that its various functions include increasing the release of gastrin, contractility of the stomach, and motility of the small intestines. Which of the following functions is also provided by this nerve?

A researcher is studying the effectiveness of a novel screening method for breast cancer. She hypothesizes that a certain ultrasound finding correlates strongly with ductal carcinomas. She conducts a clinical trial comparing this finding with the gold standard of intra-operative pathological diagnosis, and finds that the test has a 92% positive predictive value (PPV) and a 51% negative predictive value (NPV) in women between the ages of 40 and 65. Which of the following changes would occur to these values if the same study were performed in men of the same age group?

A 55-year-old man presents to his primary care physician with a 6-month history of increasing right knee pain. He says that the pain is not associated with any particular motion but is worse after heavy use. He has no significant past medical history and works as a laborer for a construction company. His past medical history is significant for peptic ulcer disease, hypertension, and type 2 diabetes. He has intermittently been taking ibuprofen for the pain and says that this helps with his symptoms. His physician diagnoses him with osteoarthritis and prescribes him celecoxib. Which of the following represents an advantage of this drug compared with ibuprofen?

A 40-year-old man presents to his primary care physician with episodic burning and severe shooting pain in his left lower abdomen radiating to the medial thigh and scrotum. Symptoms began 6 months ago and increase with walking and hip extension. The pain was initially alleviated by NSAIDs but has stopped responding to medication in the last 3 months. Past medical history includes type II diabetes mellitus and hypercholesterolemia, well-controlled on metformin and atorvastatin. Past surgical history includes open herniorrhaphy for a left-sided indirect inguinal hernia 6 months ago. The patient's temperature is 98.6°F (37°C), blood pressure is 140/80 mmHg, pulse is 90/min, and respirations are 14/min. Physical exam shows a well-healed surgical scar on the left lower abdomen with no erythema or drainage. Cremasteric reflex is absent on the left. Hemoglobin A1c from his annual exam last month was 6.8%. What is the most likely pathogenesis of this patient's shooting pain?

A 53-year-old man presents to clinic with a 2-month history of ringing in his ears and dizziness. He reports feeling unsteady on his feet while walking. He denies changes in vision, behavior, or personality. His past medical history is significant for diabetes mellitus managed with metformin. His temperature is 98.3°F (36.8°C), blood pressure is 134/76 mmHg, pulse is 79/min, and respirations are 14/min. Physical exam demonstrates gait ataxia. The Dix-Hallpike maneuver does not worsen or cause dizziness or symptoms of vertigo. On the Weber test, sound localizes to the right ear. On the Rinne test, air conduction time is longer than bone conduction time. What findings would most likely be observed on MRI of the brain?

A 27-year-old G1P0 woman presents to her obstetrician for screening at 10 weeks of gestation. A complete blood count is performed and shows a hemoglobin level of 9.7 g/dL. She denies having any symptoms and says that she has no significant past medical history. She does recall having several family members with a similar "blood" problem during their own pregnancies but is not sure about the details. Her temperature is 98.6°F (37.0°C), blood pressure is 115/70 mmHg, pulse is 90/min, and respirations are 16/min. Physical examination is unremarkable. During further workup, a sample of her red blood cells hemolyzes in a salt solution. This patient would most likely have which of the following sets of values shown in Figure A for mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), lactate dehydrogenase (LDH), and haptoglobin?

A 12-year-old boy presents to his pediatrician with a 2-month history of itchy eyes and a runny nose. His family moved from the city to their current home in the suburbs 2 years ago. Starting 2 months ago in March, he noticed that both of his eyes would become itchy every time he went outside. He has no past medical history and does not currently take any medications. On physical exam, he is found to have bilateral conjunctival injection. His symptoms are most likely caused by increased differentiation into which of the following cell types?

A 35-year-old man is brought by ambulance to the emergency department for evaluation of a headache after a minor single-vehicle motor vehicle accident. He denies any other areas of pain. He does not report any other significant past medical history and takes no medications. At the time of initial presentation, his temperature is 98°F (36.7°C), blood pressure is 115/75 mmHg, pulse is 60/min, and respirations are 13/min. Physical exam is unremarkable anddoes not any bruising to the abdomen or seatbelt sign. Laboratory studies are notable for a blood alcohol concentration of 0.15%. Non-contrast computed tomography (CT) of the head does not show intracranial bleeding, and a Focused Assessment with Sonography for Trauma (FAST) does not show any intraperitoneal free fluid. The patient is discharged home the next day. A week later, the patient returns to the emergency department complaining of severe abdominal pain. At this time, he reveals that he has had many episodes of abdominal pain. His temperature is now 98.6°F (37.0°C), blood pressure is 85/52 mmHg, pulse is 115/min, and respirations are 18/min. Abdominal CT shows a large retroperitoneal sac-like structure filled with blood but does not show evidence of intra-abdominal free air. Pathology of which of the following organs most likely precipitated this patient’s current condition?

A 26-year-old man presents to an endocrinologist at a teaching hospital for the evaluation of infertility. He has unsuccessfully tried to conceive with his partner for the past 18 months. His partner has a child from a previous relationship. The patient has no relevant past medical history. His temperature is 98.6°F (37.0°C), blood pressure is 115/70 mmHg, pulse is 65/min, and respirations are 13/min. Physical examination reveals normal external genitalia. As part of the evaluation, the endocrinologist orders several tests. Relevant findings include: Serum luteinizing hormone (LH): 12 IU/L Serum follicle-stimulating hormone (FSH): 50 U/L Total serum testosterone: 580 ng/dL (normal 300-1000 ng/dL) Decreased levels of which of the following compounds would be most directly associated with this patient’s laboratory findings?

A 37-year-old woman presents to the physician for evaluation of headache and neck pain that has persisted over the past year. Her symptoms are exacerbated by episodes of involuntarily twisting her neck. These episodes often happen when she tries to look to the side and are also associated with jerky and irregular head tremors. She has never had headaches or these episodes of involuntary movement in the past. She has not noticed any other tremors and has no other significant past medical, psychiatric, or surgical history. Her mother and paternal grandfather also experienced similar episodes of involuntary movement. Her temperature is 98.6°F (37.0°C), blood pressure is 115/70 mmHg, pulse is 60/min, and respirations are 14/min. Physical examination is notable for the neck being turned to the left and a jerky neck tremor. Which of the following is the most likely explanation for this patient’s presentation?

A 55-year-old woman presents to her primary care physician for an annual check-up. She has no acute complaints. Her medical history includes hypertension, heart failure with reduced ejection fraction (HFrEF), and type 2 diabetes. Her current medications include losartan, metoprolol, spironolactone, and metformin. She has smoked 1 pack of cigarettes per day for the past 20 years. She drinks 3-4 alcoholic beverages per week. The patient’s temperature is 98.6°F (37.0°C), blood pressure is 134/82 mmHg, pulse is 68/min, and respirations are 18/min. Her physical exam is unremarkable. Her hemoglobin A1c is 7.4%. Given her comorbidities, the decision is made to initiate a diabetes medication that reduces renal reabsorption of an osmolyte. This patient will be at increased risk for which of the following as a result of this new medication?

A 5-year-old boy presents to an urgent care clinic with lesions on his thigh shown in Figure A. He has also had 3 weeks of numbness and tingling in the area of the lesions, as well as fever and malaise. His family immigrated from Brazil 1 year ago. His past medical history is otherwise unremarkable. He is started on the standard treatment regimen for his condition. The next day, he presents to the clinic with an unremitting headache and worsening fatigue. His temperature is 98.3°F (36.8°C), blood pressure is 126/70 mmHg, pulse is 82/min, and respirations are 16/min. Pulse oximetry shows a SpO2 of 85% on room air. Physical exam is notable for a bluish discoloration of the lips and nail beds. Which of the following is the most likely pathophysiology of this patient’s symptoms?

A 39-year-old woman presents to the emergency department with a 2-week history of headache and hemoptysis. She also reports feelings of malaise and has experienced myalgias. Her past medical history is notable for chronic hepatitis C and IV drug use. Her temperature is 101.3°F (38.5°C), blood pressure is 118/68 mmHg, pulse is 106/min, and respirations are 14/min. Physical exam is notable for several track marks on her bilateral forearms. She demonstrates clear breath sounds and has a non-focal neurological exam. Her abdomen is soft and nontender. Chest radiograph shows multifocal nodular opacities. Which of the following findings is most likely to be heard on auscultation of the heart?

A 71-year-old man presents to an orthopedic trauma clinic for follow-up 1-month after operative fixation of a left hip fracture. He says that he is no longer experiencing much pain in the left hip and has been able to resume most of his daily activities. His only complaint is that he feels like he is limping despite not having any pain. On physical exam, he is found to have an abnormal gait where he shifts his body laterally to the left side. When asked to stand just on the left leg, his posterior superior iliac spine is found to be lower on the right side compared with the left side. Damage to which of the following nerves is most likely responsible for this patient's symptoms?

A 71-year-old man with a history of emphysema is brought to the emergency room due to difficulty breathing. The man reports that since this morning, he has felt winded and out of breath even walking around his house. Over the last two hours, he has started to feel winded even when sitting. At baseline, he can usually walk 1 block or 1 flight of stairs, and uses his albuterol inhaler once per week for symptom relief. He denies fever, chills, or muscle aches. His emphysema was diagnosed 5 years ago and he has never required emergency care or hospitalization for an exacerbation. He has a 50-pack year smoking history but quit after his diagnosis. On exam, his temperature is 98.6°F (36°C), blood pressure is 130/85 mmHg, pulse is 90/min, respirations are 20/min and shallow, and oxygen saturation is 90% on a 4 L/min nasal cannula. He sits hunched over and breathes through pursed lips. An arterial blood gas is drawn. Analysis of the sample will most likely show which of the following pattern of pH, carbon dioxide (pCO2), bicarbonate (HCO3-), and oxygen (PO2) (Figure A)?

A 51-year-old man presents to the emergency department with a 1-hour history of chest pain. He says that he was lifting boxes at work when he felt a heavy pressure on his chest. His past medical history is significant for obesity, diabetes, and hypertension, but he is not currently taking any medications. An electrocardiogram is taken immediately on his arrival to the emergency department and the results are shown in Figure A. Appropriate therapy is started and a procedure is emergently performed. Which of the following is the most likely potential complication of this procedure?

An 81-year-old man presents to his primary care physician with a 1-year history of increasing difficulty with urination. He says that he finds it difficult to get started urinating and often feels that he still has urine left at the end of micturition. A digital rectal exam is performed, which reveals nodules in the posterior portion of the prostate. After an appropriate workup, he is started on maintenance therapy for his condition and is told that it is extremely important to use the medication as directed because using it incorrectly results in the opposite effect. Which of the following can be expected immediately after the first dose of this medication?

An 82-year-old man is brought to the emergency department by his wife after she noticed that he had slurred speech. She says that he seemed normal that morning, but when she woke up from a nap after lunch she noticed he was laying on the couch and unable to stand. His past medical history is significant for a deep venous thrombosis that was diagnosed 1 month ago after a total knee replacement surgery. He has no other significant past medical or surgical history. He was prescribed rivaroxaban but has not been compliant with his medication. On physical exam, he is found to have drooping of his right face and weakness of his right arm. A defect in which of the following structures is most likely to explain how his past medical history contributed to his current presentation?