Which of the following decreases platelet secretion?

An 86-year-old man with a history of recurrent urinary tract infection presents with fever, tachypnea, tachycardia, mental obtundation, and reduced blood pressure. Which form of shock is most likely?

A 23-year-old man undergoes surgery for fractures of the pelvis and left femur resulting from a high-speed motor vehicle accident. The following day he develops dyspnea, speech difficulties, and a petechial skin rash. Which type of embolism is the likely cause of these findings?

A 28-year-old woman is evaluated for possible thrombophilia since she has had two episodes of deep vein thrombosis, as well as two pregnancies that terminated in spontaneous abortion. The activated partial thromboplastin time is prolonged, and she has a positive VDRL screening test for syphilis. This combination of findings is most suggestive of

A 19-year-old college sophomore is referred by his ophthalmologist because of the finding of ectopia lentis (dislocation of the lens), which has resulted in visual difficulties that have interfered with his performance on the varsity basketball team. The patient is very tall, with long limbs and long, slender, spiderlike fingers. His chest has a “caved-in” appearance, and he also has modest degree of scoliosis. A midsystolic “click” is heard, and an echocardiogram reveals mitral valve prolapse. The most likely diagnosis is

A 1-year-old female infant is hospitalized for pneumonia. Bacterial cultures of the sputum have grown Pseudomonas aeruginosa. She has had two prior hospitalizations for severe respiratory infections. Her mother has noted that when she kisses her child, the child tastes “salty.” The child has had weight loss that the mother attributes to frequent vomiting and diarrhea with bulky, foul-smelling fatty stools. The child is small for her age. Which critical protein is altered in this condition?

All of the following are anti-coagulants, except

A pathologist examines a renal biopsy from a 45-year-old man with nephrotic syndrome and requests a Congo red stain to confirm the nature of an amorphous acidophilic extracellular hyaline substance localized within the mesangial matrix of the glomeruli. A positive test confirms the presence of

Within minutes of a bee sting, a 23-year-old woman develops generalized pruritus and hyperemia of the skin, followed shortly by swelling of the face and eyelids, dyspnea, and laryngeal edema. This reaction is mediated by

A 25-year-old woman with membranous glomerulonephritis receives a kidney transplant from her HLA-matched sister. She does well initially, but after several weeks, there is a progressive increase in serum creatinine. Assuming that this represents acute cellular rejection, an infiltrate with which type of inflammatory cells is most likely to be a prominent finding on renal biopsy?

A 20-year-old woman presents with malar rash, arthralgias, low-grade fever, and high titer antibodies to double-stranded DNA and to the Sm (Smith) antigen. Which form of hypersensitivity is the primary mechanism of the abnormalities found in this disorder?

An HIV-positive intravenous drug user is suspected of having active tuberculosis, and a tuberculin (Mantoux) intradermal skin test is performed. After 48 hours, 10 cm of induration is observed. Which of the following are involved in this form of hypersensitivity reaction?

A 24-year-old woman who had previously been uneventfully transfused receives a blood transfusion during surgery and shortly thereafter develops itching, generalized urticaria, laryngeal edema, and dyspnea with wheezing respiration. She has a past history of recurrent upper respiratory tract infections and frequent episodes of diarrhea. Laboratory studies are most likely to reveal decreased concentrations of which immunoglobulin?

A 19-year-old intravenous drug user has regularly sought human immunodeficiency virus (HIV) testing, always with negative results. He admits to carelessly sharing needles on multiple occasions with individuals later found to be HIV-positive. He has heard that there is an inherited genetic basis for some people to be relatively “immune” to HIV infection. The genetic change that he is referring to is a mutation in a gene coding for which protein?

A 23-year-old man named Rogelio undergoes surgery for fractures of the pelvis and left femur resulting from a high-speed motor vehicle accident. The following day he develops dyspnea, speech difficulties, and minute 1–2 mm skin rashes. Which type of hemorrhage was apparent on the 2nd day of Rogelio?

A 68-year-old man with a long history of prostate cancer that was metastatic at the time of diagnosis has had, over the past 2 months, significant weight loss, loss of appetite, and loss of energy. His current spectrum of conditions can be attributed to which of the following?

Hemosiderin-laden macrophages are also known as

A 32-year-old man is involved in a highspeed motor vehicle accident and brought by ambulance to a Level I trauma center because of the severity of his injuries. On arrival, it is determined that he is bleeding internally, and he is taken immediately to surgery, where the surgeons find that the source of his bleeding is a severe liver laceration. A laceration is a

A 4-year-old girl is brought by her mother to the emergency department after the girl was placed in a hot bath. The patient appears to have extensive blistering of the thighs and buttocks, with slight damage to the underlying dermis. Her burns are best described as

A 38-year-old woman is receiving radiation therapy to her abdomen as adjuvant therapy for the treatment of cervical cancer. The radiosensitivity of organs or tissues within the treatment field is a limiting factor in determining the dose of radiation that can be administered. Which of the following is most susceptible to radiation damage?

A 50-year-old chronic alcoholic is seen in the emergency department with ataxic gait, confusion, confabulation, and nystagmus. This constellation of findings is the classic presentation of

A 27-year-old man who was badly burned in an industrial accident requires multiple skin grafting. While in the intensive care unit, he is found to have blood in his stools, and endoscopy confirms the presence of many small ulcers in his stomach. This complication is referred to as

Which of the following peripheral blood findings is associated with lead poisoning?

A 73-year-old man develops severe, intractable diarrhea during hospitalization for bacterial pneumonia caused by a multidrug-resistant organism. What organism is most likely responsible for his gastrointestinal symptoms?

While working with an international group of physicians to administer polio vaccines, a medical student sees several children with abdominal distention and pale streaks in the hair and skin. Cursory physical examination reveals significant hepatomegaly. The children likely suffer from

A 57-year-old man is admitted to the hospital for treatment of chronic pancreatitis. In patients with chronic pancreatitis, deficiency of which of the following vitamins is most likely?

A 54-year-old Native American living on a reservation in southwest Arizona presents to a clinic with impaired memory; diarrhea; and a rash on the face, neck, and dorsum of the hands. It is likely that this patient has a deficiency of which of the following nutrients?

A 52-year-old recent Asian immigrant is brought to the emergency department after experiencing several convulsions. Further history reveals that she has been diagnosed with tuberculosis and has recently been started on a multidrug regimen that includes

A woman from a rural Appalachian community who had recently given birth to a newborn boy at home with the aid of a midwife now brings her infant to the hospital because of continued bleeding and oozing from the umbilical stump. It is likely that the bleeding problem is secondary to a deficiency of which of the following vitamins?

A 4-year-old Inuit child from northern Alaska is brought to the pediatrician because of concern about progressive bowing of the legs and enlargement of the costochondral junctions (rachitic rosary). The underlying defect in this disorder is a defect in

An 18-year-old young man with known cystic fibrosis presents to the physician with his third episode of kidney stones in the past year. In addition, he has begun to complain of difficulty seeing at night. Such changes can be attributed to a deficiency of which vitamin?

A 45-year-old man presents with abdominal pain and hypertension. On physical examination, he is found to have an abdominal mass. Further workup confirms the diagnosis of adult polycystic kidney disease. Which of the following vascular complications is associated with this condition?

A 65-year-old man who has a long history of hypertension presents to the emergency department with tearing chest pain that radiates to the back. An electrocardiogram is normal, as are cardiac enzymes. A stat chest radiograph demonstrates widening of the mediastinum. Which of the following is the most likely?

A 14-year-old boy is brought by his family to your clinic in Utah with a long history of recurrent epistaxis. His father also reports such a history. Of the following, which is the most likely condition consistent with these findings?

A 23-year-old man known to have acquired immunodeficiency syndrome (AIDS) is seen by his primary care physician. The patient is concerned by the development of multiple red-to-purple skin plaques that have become nearly confluent on his arms and legs. The skin disorder is most likely

A 12-year-old girl undergoes bone marrow transplant as part of therapy for ALL. She subsequently presents with pulmonary complaints and neurologic findings. Lung biopsy reveals a granulomatous vasculitis with associated atypical lymphocytes. Clonality studies reveal a monoclonal B cell population with associated polyclonal T cells. What infectious agent is related to this diagnosis?

A 55-year-old woman presents with complaints of chest pain. She states that the chest pain predictably occurs when she climbs four flights of stairs to reach her apartment or when she has been jogging for more than 10 minutes. She is particularly concerned because her mother died of a myocardial infarction at 50 years of age. Which of the following best describes this patient’s state?

Yesterday, a 60-year-old man presented to the emergency department with dyspnea, diaphoresis, and crushing substernal chest pain that radiated to his neck and left arm. When asked to describe the pain, he put his fist to the center of his chest and stated that it felt “as if someone is squeezing my heart.” An electrocardiogram demonstrated changes consistent with myocardial infarction, and serum troponin I levels were elevated. If the patient unexpectedly dies today, which of the following would almost certainly be found on histologic examination of the affected myocardium?

A 60-year-old man is discharged after being observed in the hospital for 4 days following a myocardial infarction. He returns to his normal activities, which include sedentary work only. This point in time following a myocardial infarct is noteworthy for the special danger of which of the following?

A 9-year-old girl is diagnosed with acute rheumatic fever. Instead of recovering as expected, her condition worsens, and she dies. Which of the following is the most likely cause of death?

A 70-year-old woman has a long history of metastatic colon cancer, and she donates her body for use in medical school anatomy courses. At death, the body is emaciated and cachectic, and gross dissection reveals small fibrin deposits arranged around the line of closure of the leaflets of the mitral valve. The valvular lesions most likely represent

A 53-year-old woman presents with dyspnea on exertion, orthopnea, paroxysmal nocturnal dyspnea, edema in the legs and feet, and fatigue. She has no history of angina, other signs of coronary artery disease, hypertension, or valvular disease. Echocardiography reveals cardiomegaly, with four-chamber hypertrophy and dilation. Which of the following is the most likely diagnosis?

A 56-year-old woman presents with dyspnea on exertion, orthopnea, paroxysmal nocturnal dyspnea, and pulmonary edema. She also presents with severe dizziness and syncope, fatigue, weight loss, and arthralgias. After undergoing several tests, she is diagnosed with a primary heart tumor that is causing a “ball-valve obstruction” of her mitral valve. Which of the following is the most likely tumor?

A patient with severe anemia has a peripheral blood smear with oval macrocytes, hypersegmented neutrophils, and decreased platelets. The most likely cause of the anemia is

A 62-year-old man presents with pallor, fatigue, and dyspnea on exertion. A complete blood count reveals microcytic hypochromic anemia. The most likely cause of these findings is

A 72-year-old man who has recently had an aortic valve replacement now presents with pallor and fatigue. The red blood cell count is decreased, and schistocytes are reported on examination of a peripheral blood smear. In addition, his indirect (unconjugated) bilirubin is significantly elevated. The cause of the anemia is likely

A 23-year-old African-American man with a history since early childhood of severe anemia requiring many transfusions has nonhealing leg ulcers and recurrent periods of abdominal and chest pain. These signs and symptoms are most likely to be associated with which of the following laboratory abnormalities?

A 56-year-old woman with a history of breast cancer that was treated 5 years ago with lumpectomy and radiation but with no chemotherapy returns with bone pain, fatigue, and weakness. A complete blood count reveals severe anemia, as well as decreased white blood cells and platelets. Examination of a peripheral blood smear reveals small numbers of nucleated red cells, as well as an occasional “blast” cell and myelocyte. A likely cause of the hematologic abnormalities is

Military policy dictates that flight personnel in Iraq receive primaquine chemoprophylaxis for Plasmodium vivax malaria on redeploying to a non-malarious area. Several days after beginning such a regimen, a 26-year-old African-American pilot develops anemia, hemoglobinemia, and hemoglobinuria. Special studies will likely reveal an abnormality in which of the following?