A 24-year-old woman is brought to the emergency department by her roommate because she had acute onset of abdominal pain as well as confusion, nausea and vomiting, and weakness 12 hours ago. The roommate does not believe that the patient has any medical conditions or takes any medications. Body mass index is 22 kg/m². Pulse rate is 110/min, and respirations are 28/min. The patient appears flushed and is oriented only to person and place. Physical examination shows decreased skin turgor. Laboratory studies show the following: plasma glucose 304 mg/dL; arterial pH 7.2; serum bicarbonate 14 mEq/L; thyroid-stimulating hormone 2.5 µU/L; and free thyroxine 1.4 µg/dL. Urinalysis is positive for ketones. Intravenous fluids are initiated, and the patient is admitted to the internal medicine ward. Which of the following is the most likely diagnosis?

A 61-year-old man comes to the emergency department because he has had worsening fevers, chills, cough, and shortness of breath over the past 10 days. He says his symptoms started to get better a few days ago but then acutely worsened. The patient noticed some blood in his stool this morning. Medical history includes chronic obstructive pulmonary disease and hypertension, for which he uses an albuterol inhaler and takes lisinopril, respectively. He quit smoking two years ago, occasionally drinks alcoholic beverages, and does not use illegal drugs. Temperature is 39.2°C (102.6°F), pulse rate is 123/min, respirations are 24/min, and blood pressure is 146/82 mmHg. Oxygen saturation is 92% on room air. The patient is not in distress and is protecting his airway. Physical examination shows slight bleeding around the nares and gums. Non-blanching, 1-mm red macules are noted on his body but worse on his legs. Auscultation of the lungs shows coarse lung sounds and wheezing. Chest x-ray study shows diffuse interstitial infiltrates. Laboratory studies show the following: white blood cell count 21,000/mm³; hemoglobin 9.5 g/dL; hematocrit 29%; platelet count 45,000/mm³; prothrombin time 18 sec; partial thromboplastin time 42 sec; fibrinogen 180 mg/dL; and D-dimer 1500 ng/mL. Which of the following is the most appropriate initial step?

A 28-year-old woman with major depressive disorder and a history of suicidal ideation is admitted to the hospital after being found in the bathroom with an empty bottle of pills. The patient is tearful and admits that she wanted to end things and took a handful of pills she found in the bathroom cabinet about four hours ago. She says she has vomited several times and has generalized abdominal pain. Pulse rate is 90/min, respirations are 26/min, and blood pressure is 110/80 mmHg; the patient is afebrile. On physical examination, mild tenderness to palpation is noted in all quadrants of the abdomen. Extensive laboratory studies are obtained including salicylate, acetaminophen, and electrolyte levels, complete blood cell count, lactate level, arterial blood gas analysis, and liver and renal function tests. All results are within normal limits except for arterial blood gas analysis showing mild respiratory alkalosis and an elevated salicylate level of 50 mg/dL. Electrocardiography shows no abnormalities. Which of the following is the most appropriate next step in management?

A 45-year-old woman is brought to the emergency department by her partner immediately after she lost consciousness while she was getting dressed this morning. The partner witnessed the episode and did not notice any shaking or spasming; however, the patient looked very pale. She was unconscious for about 15 seconds and woke up spontaneously without any confusion or disorientation. She has no history of similar episodes, and she has not had any changes in diet or lifestyle. Medical history includes high cholesterol and diabetes mellitus. Medications include atorvastatin 40 mg and metformin 500 mg twice daily. The patient smokes about one-half pack of cigarettes per day, does not drink alcoholic beverages, and does not use illicit drugs. Pulse rate is regular and even at 102/min, and blood pressure is 110/78 mmHg. Oxygen saturation is 95% on room air. On physical examination, no carotid bruits are noted, and the lungs are clear to auscultation. No edema is noted. Laboratory studies show white blood cell count of 9000/mm³, hemoglobin level of 14 g/dL, hematocrit of 21%, creatinine level of 0.8 mg/dL, glucose level of 102 mg/dL, and prolactin level of 6 ng/mL; electrolyte levels are within normal limits. Results of a CT scan of the head are pending. Which of the following organ systems is responsible for the findings in this patient?

A 72-year-old man who comes to the clinic for routine physical examination says that he has had worsening fatigue and some slight tingling in his feet over the past three months. He also has had a 10-lb unintentional weight loss during this time. The patient has not had fevers, chills, or gastrointestinal bleeding. Medical history includes no chronic disease conditions, and he takes no medications. Temperature is 37.0°C (98.6°F), pulse rate is 90/min, and blood pressure is 128/88 mmHg. Physical examination shows no abnormalities. Laboratory findings include the following: white blood cell count 8/mm³; hemoglobin 11 g/dL; hematocrit 35%; mean corpuscular volume 90 µm³; mean corpuscular hemoglobin 30 pg/cell; mean corpuscular hemoglobin concentration 33 g/dL; platelet count 250/mm³; erythrocyte sedimentation rate 20 mm/hr; albumin-globulin ratio 0.5; thyroid-stimulating hormone 3 µU/mL; and vitamin B12 250 pg/mL. Further workup with serum protein electrophoresis shows elevated M protein. Based on these findings, this patient is at increased risk of developing which of the following conditions?

A 72-year-old man comes to the emergency department because he has had vision loss in his right eye for the past 24 hours. He says he had development of a persistent mild headache two months ago, and he now has fatigue, fever, and decreased appetite. He also says that when he tried to eat a steak yesterday, he had a very hard time chewing because of pain in his jaw. The patient does not have paralysis, weakness, or changes in mentation. He has no history of similar symptoms in the past, and he does not smoke cigarettes, drink alcoholic beverages, or use illicit drugs. Temperature is 38.2°C (100.8°F), and pulse rate is 102/min. The patient is oriented to person, place, time, and situation. Physical examination of the right temple shows an area of mild erythema with thickening and tenderness to palpation. Cranial nerves are intact; however, complete vision loss in the right eye is noted. Romberg test is negative. No weakness or numbness is noted in the extremities. Biopsy of the temporal artery is planned. Which of the following biopsy results is most likely?

A 26-year-old man comes to the internal medicine clinic because he has had redness of the eyes with associated discharge, pain with urination, and pain in his right knee and right ankle for the past five days. He says he is generally healthy and has no chronic disease conditions; however, he had Chlamydia trachomatis about five weeks ago. Temperature is 37.1°C (98.8°F), pulse rate is 80/min, respirations are 16/min, and blood pressure is 128/87 mmHg. Oxygen saturation is 98% on room air. Physical examination shows conjunctivitis, edema and tenderness to palpation of the right knee and ankle, and urethral discharge. Laboratory studies show elevated C-reactive protein level and erythrocyte sedimentation rate. Which of the following is the most likely diagnosis?

A 40-year-old man comes to the clinic for a routine physical examination. During the interview, he asks if he needs to get a colonoscopy. It is most appropriate to tell this patient that he will only need a colonoscopy at this age if he has which of the following findings on history and physical examination? 

A 63-year-old man comes to the emergency department because he has had worsening pain in the left lower quadrant of the abdomen over the past four days. He has had some diarrhea without blood and has felt feverish. Today, he says he developed urinary discomfort. Temperature is 38.3°C (101.0°F), pulse rate is 110/min, and blood pressure is 98/58 mmHg. Physical examination shows tenderness on palpation of the left lower abdomen with rigidity and guarding. A mass is palpated in the area of tenderness. White blood cell count is 18,000/mm³, and lactic acid is 3.1 mmol/L; hemoglobin and hematocrit are within normal limits. Urinalysis shows no abnormalities. Which of the following is the most likely diagnosis?

A 58-year-old man comes to the internal medicine clinic for routine follow-up. He has been keeping a log of his blood pressures, and review shows blood pressures mostly in the 140s systolic and 90s diastolic over the past two months. The patient does not currently take any medications. Body mass index is 32 kg/m². Current blood pressure is 142/90 mmHg. Laboratory studies show a hemoglobin A1c of 6.8%. Microalbuminuria is noted on urinalysis. Physical examination shows no abnormalities. Which of the following is the most appropriate initial drug therapy to manage hypertension in this patient?

An otherwise healthy 27-year-old patient who identifies as gender nonconforming comes to the clinic because of intermittent lightheadedness and palpitations during the past three weeks. Electrocardiography is shown. Which of the following is the most likely diagnosis?

A 32-year-old woman comes to the clinic because she has had slight shortness of breath with cough that is productive of slight, bloody sputum for the past week. She also has had facial flushing, weight gain, acne, and facial hair growth during the past two months. She says she does not feel ill, and she has no history of symptoms, asthma, or other lung conditions. The patient has never smoked cigarettes, drinks alcoholic beverages socially, and does not use illicit drugs. Her most recent menstrual period was two weeks ago, and she is not sexually active. Body mass index is 20 kg/m². Temperature is 36.0°C (97.6°F), pulse rate is 98/min, respirations are 12/min, and blood pressure is 178/104 mmHg. Oxygen saturation is 97%. On physical examination, the lungs are clear to auscultation. Coarse dark hair is noted on the upper lip with scattered comedones on the chin. Which of the following studies is the most appropriate next step in diagnosis?

A 43-year-old man comes to the clinic because he has had worsening fatigue and shortness of breath over the past six weeks. The shortness of breath is present even with minimal exertion. He says his partner is concerned because he occasionally stops breathing at night when he is snoring. These symptoms came on gradually and have been making it hard for him to function in activities of normal life. Medical history includes prediabetes and high blood pressure for which he takes amlodipine. He does not smoke cigarettes, drink alcoholic beverages, or use illicit drugs. Body mass index is 42 kg/m². Temperature is 37.3°C (99.2°F), pulse rate is 102/min, respirations are 22/min, and blood pressure is 128/78 mmHg. Oxygen saturation is 94%. Physical examination shows a thick neck with a crowded oropharynx. Cardiac examination shows a regular rate and a prominent S2. The lungs are clear to auscultation. Bilateral +2 pitting edema is noted in the lower extremities. Which of the following abnormal laboratory results is most likely?

A 45-year-old patient comes to the clinic because of a myriad of symptoms over the past two months. During this time, they have gained 10 lb despite no changes in diet or exercise. In addition, the patient reports fatigue, difficulty concentrating at work, hair loss, and constipation. Pulse rate is 58/min. Physical examination shows goiter. The most appropriate next step in diagnosis is the measurement of which of the following laboratory values?

A 19-year-old man comes to the primary care clinic because he has had worsening crampy abdominal pain over the past two days. He also has had subjective fevers, chills, achy swollen joints, and eye pain. The patient has noticed a tingling sensation deep within his perineum. He has not had diarrhea or constipation. On physical examination, a red ring is noted around the iris of both eyes. Severe edema of the fingers of the right hand is noted. Based on these findings, it is most appropriate to ask about which of the following aspects of this patient's history?

A 71-year-old man comes to the clinic for routine follow-up and healthcare maintenance. During the interview, he says that he is concerned about some recent skin changes on his left ear. Medical history includes chronic lymphocytic leukemia, which is stable and monitored by an oncologist, hypertension for which he takes lisinopril, hyperlipidemia for which he takes a statin, multiple sclerosis, which is stable and monitored by a neurologist, and eczema, which flares occasionally and is treated with moisturizers. The patient has a history of moderate sun exposure when he was younger, but tries to use sunscreen regularly now. Family history does not include skin cancer. On physical examination, crusty white lesions are noted on the left ear. Which of this patient's medical conditions increases his risk for skin cancer?

A 41-year-old man comes to the emergency department (ED) because he has had worsening abdominal pain, subjective fevers, and poor appetite over the past week. He is also very confused, is slurring his speech, and falls asleep multiple times during the ED intake. His partner says that he seems like he has a suntan, but he has not spent any time in the sun. The patient has not had similar symptoms in the past. Medical history is unremarkable, and he takes no medications. When he comes to, he says he usually drinks one to two pints of hard liquor daily but recently has been stressed and has increased to almost a fifth of hard liquor daily. His most recent alcoholic drink was just before coming to the ED. He has no history of intravenous drug use. Temperature is 37.2°C (98.9°F). The patient appears thin. Physical examination shows generalized jaundice including the conjunctiva. Tenderness to palpation is noted in the right upper quadrant, and the liver is protuberant. No ascites is noted. The patient seems extremely lethargic. Laboratory studies show the following: white blood cell count 13,100/mm³ with 90% neutrophils; aspartate aminotransferase 280 U/L; alanine aminotransferase 140 U/L; bilirubin 14.5 mg/dL; gamma-glutamyl transferase 290 U/L; and international normalized ratio 2.1. CT scan of the abdomen shows fatty changes to the liver without other abnormalities. Along with supportive IV fluids, which of the following is the most appropriate initial therapy?

A 28-year-old woman is admitted to the hospital after she was evaluated in the emergency department because of persistent fevers for the past six days. Medical history does not include any chronic disease conditions, but she has a history of intravenous drug use. Temperature is 38.0°C (100.4°F); all other vital signs are within normal limits. On physical examination, a new systolic murmur is heard best at the lower left sternal border. Echocardiography shows tricuspid vegetations. Which of the following is the most appropriate management?

A 34-year-old woman with type 1 diabetes mellitus comes to the internal medicine clinic for routine follow-up. The patient has no concerns. Medical history includes worsening kidney disease over the past three years. Her most recent estimated glomerular filtration rate is 35 mg/mL, and she is not yet on dialysis. Physical examination shows no abnormalities. Recent laboratory studies show hemoglobin level of 8.5 g/dL, hematocrit of 27%, and mean corpuscular volume of 92 μm³. Peripheral blood smear shows normocytic, normochromic red blood cells. Which of the following is the most likely explanation for the anemia in this patient?

A 54-year-old woman comes to the clinic because she has had worsening generalized abdominal cramping with severe watery diarrhea for the past 24 hours. She says the diarrhea is foul-smelling and green in color; she has not noticed blood in the stool. The patient says she completed a course of antibiotics 17 days ago. She has no history of recent travel or of drinking untreated water. Temperature is 38.2°C (100.8°F), pulse rate is 100/min, and blood pressure is 110/68 mmHg. The patient appears ill but not toxic. The results of urinalysis are within normal limits. A stool sample is collected for additional testing. Which of the following is the most appropriate initial drug therapy?

A 33-year-old man comes to the internal medicine clinic because he has had several intermittent episodes of “heart flutters” during the past month. He says the episodes last for 10 to 30 seconds and resolve without intervention; he has had several over the past few days. He does not have any associated chest pain or dizziness. Temperature is 37.0°C (98.6°F), pulse rate is 72/min, respirations are 16/min, and blood pressure is 124/83 mmHg. Electrocardiography shows a normal sinus rhythm. Which of the following studies is the most appropriate next step?

A 68-year-old man comes to the clinic for a routine physical examination. He says he generally feels well. Medical history includes chronic obstructive pulmonary disease, congestive heart failure, and diabetes mellitus, which are well-controlled. He is up-to-date on colon cancer screenings and immunizations. Vitals signs are within normal limits, and physical examination shows no abnormalities. Laboratory studies show the following: white blood cell count 7000/mm³; hemoglobin 10 g/dL; hematocrit 31%; mean corpuscular volume 94 µm³; mean corpuscular hemoglobin 33 pg/cell; mean corpuscular hemoglobin concentration 36 g/dL; reticulocyte count 0.3%; ferritin 254 ng/mL; vitamin B12 400 pg/mL; lactate dehydrogenase 160 U/L; and haptoglobin 113 mg/dL. Which of the following is the most likely cause of the findings in this patient? 

An 18-year-old man comes to the clinic because he has had worsening shortness of breath over the past few years. He says his symptoms have worsened significantly over the past month. The shortness of breath woke him up two times this past week, and he has been unable to continue a normal level of activity. The symptoms are usually worse with exercise but recently have become severe even during rest. The patient has been using his friends inhaler which has provided some relief. Medical history includes no chronic disease conditions, and he takes no medications. He does not smoke cigarettes, drink alcoholic beverages, or use illicit drugs. Temperature 36.7°C (98.0°F), pulse rate is 66/min, respirations are 12/min, and blood pressure is 110/80 mmHg. Oxygen saturation is 97%. The patient does not appear to be in acute distress. On physical examination, heart rate is regular with no murmurs, gallops, or rubs. Auscultation of lungs shows scattered wheezes throughout the lung fields. Which of the following medication regimens is the most appropriate initial step in treatment?

A 66-year-old man comes to the clinic due to a year of worsening shortness of breath not associated with cough, fever, hemoptysis, or a particular illness. He denies any chest pain. He has no history of recent travel or occupational/environmental exposure. The patient says a rheumatologist recently evaluated him, and all test results were negative. He takes no medications. He smoked 1/2 ppd for four years in his 20s. Oxygen saturation is 88% on room air; otherwise, his vitals are normal. The patient does not appear to be in acute distress. On physical examination, mucus membranes are pink and moist. Heart rate is regular. Auscultation of the lungs shows crackles during inspiration throughout the lung fields. No peripheral edema is noted. A CT scan of the chest shows an unusual interstitial pneumonia pattern with predominant basilar honeycombing. Which of the following medication classes is most likely to slow the progression of this patient's disease?

A 21-year-old man comes to the clinic to undergo testing for sexually transmitted infections. He has not had fevers, chills, dysuria, or penile discharge. He describes himself as gay and says that he had unprotected anal insertive intercourse two weeks ago. The patient has had four partners within the past month and six partners within the past six months. He routinely practices oral and anal intercourse with occasional use of condoms. The patient drinks one alcoholic beverage per day, smokes one half-pack of cigarettes per day, and does not use intravenous drugs. Physical examination shows normal external male genitalia without discharge or lesions. Results of urinalysis are within normal limits. Screening for gonorrhea, chlamydia, HIV, syphilis, and hepatitis B is planned. Which of the following additional interventions is most appropriate?

A 23-year-old transgender woman comes to the clinic because of a rash for the past three days. She says the rash started on her abdomen as a pink oval about 2 inches in diameter, but it has since spread to her chest, abdomen, and back. The rash does not move and is mildly itchy. Medical history includes a mild cold about three weeks ago, but she is otherwise healthy. Which of the following findings is most likely on physical examination of the rash in this patient?

A 43-year-old man comes to the internal medicine clinic for routine physical examination. He is asymptomatic, and medical history does not include any chronic disease conditions. Family medical history includes hypertension in his father, brother, and sister. The patient's blood pressure is 138/85 mmHg. Physical examination shows no abnormalities. Decreased intake of which of the following substances is most likely to decrease this patient's risk of hypertension?

A 29-year-old man comes to the clinic because he has had worsening headaches, weight gain, erectile dysfunction, decreased libido, and the development of breast tissue over the past year. He describes the headache as squeezing but not severe. He says that he and his partner have been trying to conceive for the past two years, but they have been unsuccessful. The patient recently broke his arm while throwing a baseball. Medical history is otherwise unremarkable, and he takes no medications. He does not smoke cigarettes or use illicit drugs; he drinks alcoholic beverages occasionally. Which of the following findings on physical examination is most likely?

A 38-year-old woman, gravida 3, para 3, is admitted to the hospital for treatment of upper abdominal pain that is severe and radiates to her back. She also has nausea and vomiting and cannot keep anything down. The patient has had similar symptoms in the past but never this bad. Sitting up and leaning forward gives her some relief of her pain but nothing else has helped. The patient admits to drinking heavily over the past six days. She typically drinks one to two pints of hard liquor daily. Body mass index is 36 kg/m². Temperature is 37.0°C (98.6°F), pulse rate is 118/min, and blood pressure is 110/86 mmHg. Physical examination shows tenderness to palpation in the epigastric region. Laboratory studies show the following: white blood cell count 13,000/mm³; alkaline phosphatase 50 U/L; creatinine 1.1 mg/dL; aspartate aminotransferase 305 U/L; alanine aminotransferase 150 U/L; and lipase 710 U/L. The result of a quantitative beta-human chorionic gonadotropin test is negative. A test of the stool for blood is negative. RUQ ultrasonography shows no abnormalities. Which of the following is the most appropriate initial management? 

A 69-year-old woman comes to the emergency department because she has had worsening dizziness and dyspnea on exertion for the past four days. Medical history includes breast cancer, and she has a history of cigarette smoking. Pulse rate is 118/min, respirations are 26/min, and blood pressure is 82/40 mmHg. Oxygen saturation is 88% on room air. Physical examination shows distant heart sounds. Blood pressure markedly decreases with inspiration. Which of the following is the most likely diagnosis?

A 39-year-old woman comes to the clinic because she has had weakness on and off for the past eight months. The patient says that her eyes feel tired and she has double vision in the afternoon. Eating dinner has become harder for her because her jaw gets tired; she has to focus on eating otherwise she sometimes chokes. Her legs have been very weak recently; she has to rest when she climbs the stairs to her apartment when she returns home from work at the end of the day. The symptoms are relieved by rest and are not present when she wakes up in the morning. She does not have difficulty breathing, have any bowel or bladder symptoms, or any numbness or tingling. She has noticed that hot showers and temperatures affect her symptoms. The patient does not smoke cigarettes, drink alcohol, or use illicit drugs. Temperature, heart rate, respirations, and blood pressure are within normal limits. Oxygen saturation is 97%. On physical examination, the pupils are equal and reactive to light. Skin sensation is intact. Muscle strength is equal and 5/5. Which of the following medications is the most appropriate initial treatment?

A 48-year-old man comes to the clinic for a routine physical examination. Medical history includes chronic lymphocytic leukemia. He says he is feeling well, but is concerned about contracting pneumonia since he has not been immunized in the past. Which of the following is the most appropriate recommendation?

A 76-year-old man comes to the clinic because of worsening shortness of breath over the past year. He says it's difficult to walk up stairs or around the store. He has not had any cough, wheezing, or fever. He has not taken anything for the symptoms but has altered his activities to avoid feeling short of breath. Medical history includes hypertension and hypercholesterolemia, both stable on medications, and prostate cancer treated with prostatectomy. He worked as a shipyard engineer in the Navy for 20 years before retiring and then worked as a diesel mechanic. The patient has never smoked cigarettes. Temperature is 37.0°C (98.6°F), pulse rate is 90/min, and blood pressure is 130/56 mmHg. Oxygen saturation is initially 88% but improves to 92% with rest. Auscultation of the lungs shows decreased chest expansion and bibasilar rales most noticeable over the lateral bases. Prominent clubbing of the fingers is noted. No edema or jugular venous distention is noted. Bedside pulmonary function tests show decreases in FVC, FEV1, and TLC as well as a normal FEV1/FVC ratio. Which of the following mechanisms is most likely causing the symptoms in this patient?

A 34-year-old woman comes to the clinic because she has had rhythmic and involuntary movement of the arms during the past year. She says the symptoms started with involuntary finger movements that then progressed to involve her wrists and forearms. Over the past two years, the patient has had irritability and impulsivity, which prompted her to be evaluated for possible bipolar disorder. She says she used to be very organized but has been scattered and has had a hard time concentrating over the past two years. Temperature is 37.1°C (98.8°F), pulse rate is 80/min, respirations are 16/min, and blood pressure is 128/87 mmHg. Oxygen saturation is 98% on room air. Which of the following is the most important question to ask this patient?

A 33-year-old man comes to the internal medicine clinic because he has had dark urine and intermittent abdominal pain during the past week. Medical history includes no chronic disease conditions, and he has no history of recent trauma. He does not know his family’s past medical history well, though he thinks that his mother had some kidney and liver issues. Temperature is 36.7°C (98.0°F), pulse rate is 80/min, respirations are 16/min, and blood pressure is 168/102 mmHg. Oxygen saturation is 98% on room air. Physical examination shows a late systolic crescendo murmur with a mid systolic click. Abdominal examination shows bilateral masses that are tender to palpation. Results of urinalysis are positive for red blood cells, negative for white blood cells, negative for casts, and negative for nitrites. Which of the following diagnostic modalities is most appropriate to use to screen members of this patient’s family to assess if they are affected by the same condition?

A 55-year-old woman comes to the clinic because she has had worsening shortness of breath and cough over the past few years. She says she normally gets better after treatment, but she has been coughing up clear mucus, has had shortness of breath, and has had some slight pain in the chest wall over the past six months. Recent results of testing for asthma and heart conditions were negative. Medical history includes rheumatoid arthritis and Sjögren syndrome. She has never smoked cigarettes and does not drink alcoholic beverages or use illicit drugs. Temperature is 36.5°C (97.7°F), pulse rate is 90/min, respirations are 12/min. Oxygen saturation is 90% on room air. The patient does not appear to be in acute distress but coughs occasionally throughout the interview. On physical examination, cachexia is noted. Mucus membranes are pink, very dry, and without discharge. No cervical lymphadenopathy is noted. Auscultation of the lungs shows bilateral basilar crackles with rare wheezing. No peripheral edema is noted. The fingertips look like an upside down spoon. Chest x-ray study shows parallel linear densities with tram-track opacities and ring shadows; no infiltrates are noted. Which of the following is the most likely diagnosis?

A 68-year-old man comes to the emergency department because he has felt dizzy and light-headed for the past one week. Medical history includes hypertension, and he is compliant with hydrochlorothiazide therapy. The patient has not had any recent infections or changes to his medications. Blood pressure is 74/42 mmHg, and orthostatic blood pressures are positive. Laboratory studies show blood urea nitrogen of 32 mg/dL and creatinine of 1.5 mg/dL (baseline creatinine is 0.8 mg/dL). Urinalysis show no casts but increased specific gravity. Intravenous fluids are administered, and the patient is admitted to the internal medicine service. Subsequent laboratory studies show blood urea nitrogen of 26 mg/dL and creatinine 1.1 mg/dL. Which of the following is the most likely explanation for the acute kidney injury in this patient?

A 30-year-old woman comes to the clinic because she has had a 15-lb unintentional weight loss over the past two months despite having an increased appetite. She also has had recent onset of tremors. Temperature is 37.0°C (98.6°F), pulse rate is 105/min, respirations are 16/min, and blood pressure is 121/62 mmHg. Oxygen saturation is 100%. On physical examination, a goiter is noted. Which of the following locations in the brain is most likely responsible for the initial hormone production causing the suspected imbalance in this patient?

A 58-year-old woman comes to the internal medicine clinic because she has had a lump on the anterior portion of her neck around the area of the thyroid gland for the past three months. She has no other symptoms. Medical history includes hypertension, for which she takes hydrochlorothiazide. Temperature is 37.1°C (98.8°F), pulse rate is 80/min, respirations are 16/min, and blood pressure is 128/87 mmHg. Oxygen saturation is 98% on room air. On physical examination, a smooth nodule can be felt on the right side of the thyroid gland, which stays fixed in place on swallowing. Laboratory studies show a thyroid-stimulating hormone level of 2.4 µU/L. The patient undergoes fine-needle aspiration biopsy and follicular neoplasm is diagnosed. Which of the following is the most appropriate next step in management?

A 33-year-old transgender man with diabetes mellitus comes to the internal medicine clinic for follow-up to discuss recent laboratory results. Laboratory studies show a fasting plasma glucose level of >126 mg/dL on two occasions and hemoglobin A1c of 7.2%. He has tried diet and exercise changes with limited success. Medication needs to be initiated, and a first-line oral antihyperglycemic agent is chosen. This medication decreases hepatic glucose production as well as intestinal absorption while increasing the body's sensitivity to insulin, and most likely belongs to which of the following classes of antihyperglycemic agents?

A 51-year-old woman comes to the clinic for routine physical examination. She has no symptoms and has been feeling well. Medical history includes no chronic disease conditions, and she takes no medications. Family history includes breast cancer in her mother and heart disease in her father. She smoked one pack of cigarettes per day for 20 years, but she quit five years ago. She drinks two alcoholic beverages per week and does not use illicit drugs. Temperature is 37.0°C (98.6°F), pulse rate is 90/min, respirations are 12/min, and blood pressure is 128/80 mmHg. Oxygen saturation is 92% on room air. On physical examination, the lungs are clear to auscultation. No peripheral edema is noted. To screen this patient for lung cancer, which of the following studies is most appropriate?

A 72-year-old woman is brought to the emergency department by ambulance because she woke up this morning and was confused about where she was. She has had fever, cough, and worsening shortness of breath over the past four days. Medical history includes urinary tract infection two months ago in which she was admitted to the hospital for treatment for three days. The patient finished a course of ciprofloxacin after discharge and has not had any urinary symptoms since that time. Temperature is 39.0°C (102.2°F), pulse rate is 116/min, respirations are 22/min, and blood pressure is 110/80 mmHg. Oxygen saturation is 90%. The patient is now oriented to person, place, time, and situation. On physical examination, mucous membranes are dry. Lung sounds are coarse, and E to A changes are noted. Heart sounds are regular without murmurs, gallops, or rubs. Abdominal examination shows no abnormalities. No edema or skin changes are noted. Complete blood cell count shows a white blood cell count of 21,000/mm³, neutrophils of 91%, and immature granulocytes of 3%. Creatinine level is 2.5 mg/dL, and lactic acid level is 3.1 mEq/L. Results of urinalysis are within normal limits. Chest x-ray study shows infiltrates. Which of the following are the most likely causative agents?

A 65-year-old man with a history of hypertension, hyperlipidemia, and tobacco use comes to the clinic because he has had pain in the left calf during the past three months. He works as a mail carrier and says that the pain starts after he walks about a half mile and resolves if he rests for about 15 minutes, at which time he is able to resume walking. Temperature is 37.1°C (98.8°F), pulse rate is 78/min, respirations are 16/min, and blood pressure is 126/88 mmHg. Oxygen saturation is 98% on room air.  On physical examination, the left lower extremity is dry, shiny, and hairless. It is slightly cooler to touch than the right. Based on these findings, which of the following is the most appropriate initial study?

A 45-year-old woman is being treated in the hospital for respiratory distress. Her symptoms started 48 hours ago with cough and fevers. She takes no medications. She is a current smoker and has a 20-pack-year history of cigarette smoking. Temperature is 38.9°C (102.0°F), and pulse rate is 130/min. White blood cell count is 21,000/mm³, neutrophils are 90%, lymphocytes are 15%, monocytes are 4%, eosinophils are 3%, and immature granulocytes are 6%. Toxic granulocytes are noted. Which of the following is the most likely explanation for these findings?

A 59-year-old man with diabetes mellitus and hypertension comes to the internal medicine clinic for routine follow-up examination. At his most recent visit, laboratory studies showed total cholesterol level of 220 mg/dL and high-density lipoprotein (HDL) cholesterol level of 30 mg/dL. His 10-year risk for atherosclerotic cardiovascular disease was calculated at 28.6%, and drug therapy was initiated. Current laboratory studies show total cholesterol level of 140 mg/dL and HDL cholesterol level of 50 mg/dL. Based on these findings, which of the following drugs has this patient most likely been taking?

A 32-year-old woman who is being treated in the hospital after undergoing laparoscopic cholecystectomy two days ago has had altered mental status for the past 30 minutes. Medical history includes well-controlled Graves disease. Pulse rate is 148/min, respirations are 22/min, and blood pressure is 165/110 mmHg. Oxygen saturation is 95%. Laboratory studies obtained this morning show white blood cell count of 7000/mm³, thyroid-stimulating hormone level of .018 µU/L, free thyroxine level of 3.5 µg/dL, and glucose level of 98 mg/dL. In addition to a beta-blocker, which of the following medications is most appropriate to administer to this patient?

A 32-year-old woman comes to the internal medicine clinic because she has had palpitations during the past year. Medical history includes group A streptococcal pharyngitis at 8 years of age. She says she was suspected of having rheumatic fever at that time and was initially treated with antibiotics, but she did not return for follow-up. Based on these findings, which of the following is most likely to be heard on cardiac auscultation?

A 43-year-old man comes to the emergency department because he had an acute onset of severe, colicky pain in the left flank four hours ago. He says the pain radiates to his left groin. Medical history includes hypertension treated with hydrochlorothiazide. Urinalysis shows microscopic hematuria. A non-contrast CT scan shows an 8-mm stone at the ureteropelvic junction. Intravenous fluids and analgesics are administered. Which of the following findings on physical examination is most likely? 

A 32-year-old man comes to the clinic because he has had a rash, easy bruising, and bloody noses during the past six months. Medical history includes no chronic disease conditions. He has never had similar symptoms in the past, and he takes no medications. The patient describes himself as a gay man; he smokes one-half pack of cigarettes daily and drinks socially on the weekends. Physical examination shows multiple bruises on the arms and legs. Urinalysis is positive for blood as is fecal occult blood test. Laboratory studies show hemoglobin and hematocrit within normal limits and a platelet count of 35,000/mm³. HIV test is reactive. Immune thrombocytopenic purpura is diagnosed. Which of the following is the mechanism most likely causing the symptoms in this patient?