A 72-year-old man presents to the emergency department because he felt dizzy when rising from a seated to a standing position. Since this occurred, he has developed a headache. He says that he first began feeling this way when standing up from the toilet, when he immediately felt lightheaded as if he was going to faint. He sat down on the floor and felt better after 15 seconds. His past medical history is significant for allergies, diabetes mellitus, hypertension, benign prostatic hyperplasia, and arthritis. He takes metformin, lisinopril, prazosin, diphenhydramine, and ibuprofen daily. He recently started one of these medications but does not remember which one it was. Which of the following medications is most likely responsible for this patient's symptoms?

A 42-year-old woman presents to her primary care physician with a 1-year history of increasing joint pain. She says that she started noticing that her hands felt stiff while doing laundry but that over the course of the year it has progressed to include stiffness when performing almost all physical activities. She has also experienced bilateral knee pain while walking. Her past medical history is significant for obesity with a past sleeve gastrectomy. Her temperature is 99°F (37.2°C), blood pressure is 117/72 mmHg, pulse is 91/min, and respirations are 12/min. On physical exam, she is found to have enlarged, tender nodules over her metacarpophalangeal joints but no rashes or mucosal changes. A laboratory study is performed showing that her red blood cells settle more quickly than would be expected in a healthy patient. Which of the following signaling factors is most likely responsible for this finding?

A 2-year-old boy is brought to a pediatrician to establish care after he was adopted from abroad. His adoptive parents say that they do not know his past medical history but report that he is playful and appears to be developing as expected. On physical exam, he is found to have a high-pitched and harsh holosystolic murmur that is best heard at the lower left sternal border. Which of the following changes in ventricular pressures would most likely be seen in this patient?

A 79-year-old woman presents to her dermatologist for continued monitoring of her melanoma. She has no acute complaints today. She was started on an immune checkpoint inhibitor at the last visit and has noticed that the lesion appears to be getting paler over time. She has no significant past medical history other than melanoma and says that she has been diligently taking her medication. Which of the following is the most likely cause of the loss of color in the lesion?

A 28-year-old man presents to an urgent care clinic with a 1-day history of cough and upper airway irritation after being caught in a dust storm at a music festival. He says that he has noticed dust particles in his sputum and has significant discomfort when breathing deeply. He has no significant past medical history, and his symptoms resolve over the course of the next week. Which of the following cell types is primarily responsible for mechanically removing dust particles from the upper airways of this patient?

A 61-year-old man presents to his transplant surgeon with a 1-week history of increasing shortness of breath, fatigue, and inability to lay flat at night. His past medical history is significant for cardiomyopathy for which he had a cardiac transplant surgery 3 weeks ago. He initially felt he was recovering well, but noticed that he started having difficulty catching his breath about 2 weeks after the surgery. On physical exam, he is found to have jugular venous distention to 7 cm above the sternal angle and peripheral edema. Which of the following would most likely be seen on histology for this patient?

A 35-year-old woman presents to a transplant surgeon for a consultation about becoming a living kidney donor for her son. The patient’s son developed end-stage kidney disease due to a congenital condition. Appropriate testing is performed on both the patient and her child. As part of surgical planning, an abdominal computed tomography (CT) scan is performed (Figure A). Which of the following arteries supplies the structure labeled with the yellow arrow in Figure A?

A 51-year-old man presents to the ophthalmologist with increasing difficulty reading books and working on his computer over the past few years, even when wearing his normal glasses. He has needed glasses for distance vision since he was a child but has recently noticed that he can see far away objects more clearly than before. He denies flashes, floaters, visual distortions, or eye pain. His past medical history is significant for diabetes, hypertension, and hypercholesterolemia. His medications include metformin, lisinopril, and rosuvastatin. He has had no previous ocular surgeries. Both his parents have macular degeneration. His uncorrected visual acuity is 20/60 in both eyes at near and 20/40 at distance. With appropriate spectacle correction, his visual acuity is 20/20 in both eyes at near and at distance. Intraocular pressures are 14 mmHg bilaterally (normal 12-21 mmHg). Pupils are equal, round, and reactive to light. Which of the following is the most likely mechanism underlying this patient’s change in vision?

A 33-year-old G1P0 woman presents to an infertility specialist due to difficulty with conceiving a child. She has been regularly having sex without contraceptive use for the past 12 months without success. Her husband has a child from his previous marriage. She has no significant previous medical or surgical history. Her temperature is 98.6°F (37.0°C), blood pressure is 115/70 mmHg, pulse is 75/min, respirations are 16/min, and O2 saturation is 99% on room air. A physical examination, including a bimanual pelvic examination, is unremarkable. Further diagnostic testing is performed, which incidentally reveals a membrane in the uterus that extends to the cervix. Abnormalities in the development of which of the following structures led to this finding?

A scientist is studying a novel hepatitis virus that recently spread from animals to humans. She studies the viral proteins using crystallography and analyzes the overall structure of the virus using scanning electron microscopy. She finds that the virus is likely a member of the picornavirus class and functions similarly to the other hepatitis viruses in that class. In order to leverage this similarity, she adapts an existing hepatitis vaccine against this class of viruses to generate a new vaccine with the same effect. Which of the following is the most likely mechanism of action for this new vaccine?

A 34-year-old man presents to the primary care physician for fertility concerns. He has been attempting unsuccessfully to conceive with his 30-year-old wife for the past 12 months. They are having unprotected sexual intercourse timed to her ovulatory cycles. He reports no other symptoms, including fevers, chills, or cough. His medical problems consist of asthma and diabetes for which he uses an albuterol inhaler as needed and takes metformin. He had 1 episode of pneumonia 2 years ago that was treated outpatient. He has had no prior surgeries. He works as a software engineer. He is divorced and has no prior children. His wife is also divorced and has 1 child from a prior marriage. He smokes 1 pack of cigarettes per day and drinks alcohol socially. He denies illicit drug use. The patient’s temperature is 98.6°F (37.0°C), blood pressure is 120/70 mmHg, pulse is 70/min, and respirations are 18/min. Physical examination reveals a tan-appearing man in no acute distress. Cardiac auscultation reveals a normal S1 and S2. The bilateral lung fields are clear. There is no tenderness to abdominal palpation. Bowel sounds are present. Which of the following is the most likely diagnosis?

A 12-year-old boy with a history of diplegic cerebral palsy presents for orthopaedic surgery evaluation because of his contractures. Specifically, he was able to walk with a walker as a child but recently went through a growth spurt and lost his ability to walk. He is upset that he is now wheelchair bound and wants to know why his legs feel really tight compared to when he was younger. His temperature is 98.6°F (37°C and vice versa), blood pressure is 113/69 mmHg, pulse is 71/min, and respirations are 11/min. Physical exam shows significant spasticity when he flexes his hip in the wheelchair. Which of the following muscles is the most likely cause of this finding?

A 61-year-old man presents to his primary care physician with a 1-year history of increasing left knee pain. He says that he first started noticing the pain while walking with his wife but it now occurs daily. He says that the pain is worst in the evenings and with activity. His past medical history is significant for obesity and hypertension for which he is taking lisinopril. His temperature is 98.6°F (37°C), blood pressure is 141/74 mmHg, pulse is 82/min, and respirations are 11/min. He says that he has been taking turmeric for the joint pain and wants to know if this is an appropriate treatment. Which of the following is the best response to this question?

A 45-year-old woman presents to the emergency department with abdominal pain. She had just finished eating dinner when she experienced sudden, severe abdominal pain below her right costal margin. The pain is 8/10 in severity, constant, and radiates to the right shoulder. She also complains of nausea and vomiting. Her medical history is notable for hypertension and menorrhagia. Her medications consist of amlodipine. She has had 2 prior Cesarean sections. She is a non-smoker and drinks alcohol socially. She denies illicit drug use. The patient’s temperature is 98.6°F (37.0°C), blood pressure is 140/70 mmHg, pulse is 100/min, and respirations are 18/min. Her body mass index is 32.4 kg/m^2. Physical examination reveals a normal S1 and S2 on cardiac auscultation. The bilateral lung fields are clear. The abdomen is soft with discomfort to deep palpation in the right upper quadrant. The sclera are anicteric. The results of serum laboratory tests are shown below: Hemoglobin: 9.8 g/dL Hematocrit: 29.4% Leukocyte count: 5,000/mm^3 with normal differential Platelet count: 300,000/mm^3 Mean corpuscular volume: 75 µm^3 Alkaline phosphatase: 50 U/L Aspartate aminotransferase (AST, GOT): 16 U/L Alanine aminotransferase (ALT, GPT): 18 U/L Gamma-glutamyltransferase (GGT): 26 U/L The patient is given intravenous pain medications and intravenous fluids. Four hours later, her pain is rated as 1/10 in severity. Which of the following is the most likely cause of this patient’s symptoms?

A 67-year-old woman presents to her primary care physician with urinary leakage. She states that there have been multiple times where she felt the need to urinate but was unable to make it to the bathroom in time. She has been wearing diapers for her symptoms. Her medical problems include hypertension, hyperlipidemia, and type 2 diabetes mellitus, for which she takes amlodipine, atorvastatin, and metformin. She underwent a laparoscopic ventral hernia repair 3 weeks ago. Her obstetric history consists of 3 prior pregnancies, all delivered vaginally. She has a 25-pack-year smoking history but quit 5 years ago. She drinks alcohol socially and denies illicit drug use. Her temperature is 98.6°F (37.0°C), blood pressure is 130/70 mmHg, pulse is 70/min, and respirations are 18/min. Physical examination reveals an elderly woman in no acute distress. A cardiopulmonary examination is unremarkable. When the urethra is directly visualized and the patient is asked to perform the Valsalva maneuver, there is no visualized urinary leakage. The vaginal mucosa appears healthy with normal rugae. A post-void residual bladder scan shows 40 mL of urine. Which of the following describes the mechanism of the most appropriate treatment for this patient’s condition?

A 38-year-old woman presents to her primary care physician with 3 months of increasing abdominal bloating. Her bloating sensation is not associated with meals and is associated with mild abdominal discomfort, watery diarrhea, and flatulence, which all began around the same time. She has not had any fevers, chills, nausea, or vomiting. She denies having oily, floating stools. Her medical problems consist of hypertension, hyperlipidemia, type 2 diabetes, and obesity. Her medications consist of amlodipine, losartan, atorvastatin, metformin, and empagliflozin. She has a history of right knee meniscal debridement 10 years ago and a Roux-en-Y gastric bypass 6 months ago. She works as a teacher and several of her students were sick with a diarrheal illness 2 weeks ago. She returned from a trip to Honduras 5 months ago. She went to a barbecue last week, where she ate salad and a chicken sandwich. The patient’s temperature is 98.6°F (37.0°C), blood pressure is 118/70 mmHg, pulse is 70/min, and respirations are 18/min. Physical exam reveals a normal S1 and S2 with no murmurs. Her lungs are clear to auscultation bilaterally. Her abdomen is soft and mildly distended. There is discomfort to deep palpation in the upper quadrants but no frank tenderness. There is no peripheral edema. The results of laboratory testing is shown below: Hemoglobin: 11.2 g/dL Platelet count: 250,000/mm^3 Mean corpuscular volume: 108 µm^3 Lactate dehydrogenase: 200 U/L Which of the following is the most likely cause of this patient’s symptoms?

A 45-year-old man presents to his primary care physician with fatigue. He has felt abnormally tired over the past 6 months and is unable to run more than 1 mile anymore. Prior to this, he was a marathon runner. He has had no fevers, chills, constipation, heat or cold intolerance, or syncopal episodes. He further denies headaches or vision changes. He has a history of Hodgkin lymphoma 3 years ago for which he underwent multiple cycles of chemotherapy. He currently takes no medications. He has had no prior surgeries. He works as a grocery store shelf stocker. He is sexually active with his girlfriend of 5 years, but has had no libido in the past 3 months which has caused substantial issues with his partner. The patient’s temperature is 98.6°F (37.0°C), blood pressure is 120/70 mmHg, pulse is 70/min, and respirations are 15/min. Physical exam shows a tired-appearing man. There are no palpable neck masses. Cardiac exam shows a normal S1 and S2 without murmurs. His lungs are clear bilaterally. His abdomen is soft and nontender. A genital exam shows small bilateral testes without masses. There is firm, rubbery tissue that is prominent under his bilateral areolas. He has a normal mood. An appropriate test confirms the suspected diagnosis. An MRI of his brain is unremarkable. Which of the following treatments would most likely improve this patient’s symptoms?

A 50-year-old woman presents to her physician for joint pains. She has been having increasing pain in her bilateral wrists and metacarpophalangeal joints for the past 3 months. She has a history of rheumatoid arthritis and has baseline wrist pain, but this pain has been progressive. The pain has been limiting her ability to work. Her other medical problems consist of hypertension and hyperlipidemia. Her medications consist of methotrexate, ibuprofen, amlodipine, losartan, and atorvastatin. She has been on methotrexate for 5 years with good control of her symptoms until now. She works as a local schoolteacher. Physical exam reveals a well-appearing woman in no acute distress. Cardiac auscultation reveals a normal S1 and S2 without murmurs. Her lungs are clear to auscultation bilaterally. Her abdomen is soft, nondistended, and nontender. Examination of her upper extremities reveals firm lumps near her metacarpophalangeal joints and elbows. There is ulnar deviation of her digits bilaterally. The decision is made to initiate rituximab treatment. One week later, the patient returns complaining of fever and a pruritic rash. She denies changes in bowel function or flatulence. The patient's temperature is 101.5°F (38.6°C), blood pressure is 138/90 mmHg, pulse is 90/min, and respirations are 14/min. Physical exam reveals an urticarial rash on the torso and extremities. Lungs are clear bilaterally with good air movement. There is no nuchal rigidity. Which of the following factors is most likely responsible for this patient's skin findings?

A 20-year-old woman presents to her primary care physician with a 3-week history of rash on her right shoulder. She says that she first noticed itching in her right shoulder while showering after gymnastics practice. Since then, she has noticed the rash expanding. Her past medical history is significant for asthma for which she uses an albuterol inhaler as needed. Her temperature is 98.6°F (37°C), blood pressure is 112/71 mmHg, pulse is 91/min, and respirations are 12/min. Physical exam reveals the finding shown in Figure A. Which of the following most appropriately describes the pathophysiology of this disease?

A scientist is studying the mechanisms by which a novel compound is able to treat bacterial infections. She discovers that it binds selectively and irreversibly to a bacterial protein and inhibits the function of the active site of this protein. The scientist isolates this protein and finds that it is able to bind to both RNA and DNA strands. When bound to RNA substrates, the protein results in removal of short segments of RNA. When bound to DNA substrates, the protein results in addition of short segments of DNA. She then crystallizes the protein and finds that it is most commonly located on replicating strands of DNA. Which of the following is the most likely target of this novel pharmaceutical?

An 82-year-old man presents to his oncologist for further management of his melanoma. He has previously been on several lines of therapy but his melanoma has progressed despite treatment. His oncologist tells him that a novel therapy is currently in clinical trials and that he is eligible for enrollment. When the patient asks how the novel medication works, he is told that the medication increases the chance that a cytotoxic immune cell will recognize the cancer cells and result in cell death. Which of the following is most likely being targeted by this novel therapy?

A 32-year-old female presents to your fertility clinic following inability to conceive with her husband for the past two years. The patient reports a long history of oligomenorrhea. Physical examination is notable for acanthosis nigricans around the folds of the neck and hair on the patient's upper lip. Increasing levels of which of the following hormones is likely to help this patient’s fertility problem: