Chemical mediators of inflammation — MCQs

A 6-year-old boy is presented to a pediatric clinic by his mother with complaints of fever, malaise, and cough for the past 2 days. He frequently complains of a sore throat and has difficulty eating solid foods. The mother mentions that, initially, the boy’s fever was low-grade and intermittent but later became high grade and continuous. The boy was born at 39 weeks gestation via spontaneous vaginal delivery. He is up to date on all vaccines and is meeting all developmental milestones. The past medical history is noncontributory. The boy takes a multivitamin every day. The mother reports that he does well in school and is helpful around the house. The boy’s vital signs include blood pressure 110/65 mm Hg, heart rate 110/min, respiratory rate 32/min, and temperature 38.3°C (101.0°F). On physical examination, the boy appears uncomfortable and has difficulty breathing. His heart is mildly tachycardic with a regular rhythm and his lungs are clear to auscultation bilaterally. Oropharyngeal examination shows that his palatine tonsils are covered with pus and that there is erythema of the surrounding mucosa. Which of the following mediators is responsible for this patient’s elevated temperature?

A 34-year-old man comes to the physician because of palpitations, shortness of breath, diarrhea, and abdominal cramps for 2 months. Physical examination shows cutaneous flushing of the face. Auscultation of the chest shows bilateral wheezing. A 24-hour urine collection shows increased 5-hydroxyindoleacetic acid (5-HIAA) concentration. A contrast-enhanced CT scan of the abdomen shows an intestinal tumor with extensive metastasis to the liver. A diagnosis of an inoperable disease is made and the patient is started on treatment with octreotide. Six weeks later, the patient's symptoms have improved except for his abdominal pain and frequent loose stools. The physician suggests enrolling the patient in a trial to test additional treatment with a new drug that has been shown to improve symptoms in other patients with the same condition. The expected beneficial effect of this new drug is most likely caused by inhibition of which of the following?

An investigator is studying the effect of different cytokines on the growth and differentiation of B cells. The investigator isolates a population of B cells from the germinal center of a lymph node. After exposure to a particular cytokine, these B cells begin to produce an antibody that prevents attachment of pathogens to mucous membranes but does not fix complement. Which of the following cytokines is most likely responsible for the observed changes in B-cell function?

A 55-year-old woman with diabetes presents to the emergency department due to swelling of her left leg, fever, and chills for the past 2 days. The woman’s maximum recorded temperature at home was 38.3°C (101.0°F). Her left leg is red and swollen from her ankle to the calf, with an ill-defined edge. Her vital signs include: blood pressure 120/78 mm Hg, pulse rate 94/min, temperature 38.3°C (101.0°F), and respiratory rate 16/min. On physical examination, her left leg shows marked tenderness and warmth compared with her right leg. The left inguinal lymph node is enlarged to 3 x 3 cm. Which of the following chemical mediators is the most likely cause of the woman’s fever?

A researcher is studying the circulating factors that are released when immune cells are exposed to antigens. Specifically, she is studying a population of CD2+ cells that have been activated acutely. In order to determine which factors are secreted by these cells, she cultures the cells in media and collects the used media from these plates after several days. She then purifies a small factor from this media and uses it to stimulate various immune cell types. She finds that this factor primarily seems to increase the growth and prolong the survival of other CD2+ cells. Which of the following is most likely the factor that was purified by this researcher?

A father brings his 3-year-old son to the pediatrician because he is concerned about his health. He states that throughout his son's life he has had recurrent infections despite proper treatment and hygiene. Upon reviewing the patient's chart, the pediatrician notices that the child has been infected multiple times with S. aureus, Aspergillus, and E. coli. Which of the following would confirm the most likely cause of this patient's symptoms?

A 7-year-old boy with asthma is brought to the physician because of a 1-month history of worsening shortness of breath and cough. The mother reports that the shortness of breath usually occurs when he is exercising with his older brother. His only medication is an albuterol inhaler that is taken as needed. The physician considers adding zafirlukast to his drug regimen. Which of the following is the most likely mechanism of action of this drug?

Two days after being admitted for acute myocardial infarction, a 61-year-old man has sharp, substernal chest pain that worsens with inspiration and improves when leaning forward. Cardiac examination shows a scratchy sound best heard over the left sternal border. Histopathological examination of the infarcted myocardial tissue is most likely to show which of the following findings?

A 4-year-old Caucasian boy is brought by his mother to the pediatrician with a red and swollen elbow. He was playing outside a few days prior to presentation when he fell and lightly scraped his elbow on the sidewalk. He was born at 34 weeks' gestation and was in the neonatal ICU for 2 days. His temperature is 102.1°F (38.9°C), blood pressure is 105/65 mmHg, pulse is 110/min, and respirations are 20/min. On exam, he has a swollen, erythematous, fluctuant, and exquisitely tender mass on his right elbow. There is expressible purulence coming from his wound. A peripheral blood smear in this patient would most likely reveal which of the following findings?

A 32-year-old man who recently emigrated from Somalia comes to the physician because of a 4-week history of fever, cough, and chest pain. He has had a 5-kg (11-lb) weight loss over the last 3 months despite no changes in appetite. His temperature is 38.1°C (100.6°F). Physical examination shows enlarged cervical lymph nodes. The lungs are clear to auscultation. The results of an interferon-γ release assay are positive. An x-ray of the chest shows bilateral mediastinal lymphadenopathy. A transbronchial needle aspiration biopsy of a mediastinal lymph node is performed; a photomicrograph of the specimen is shown. The structure indicated by the arrow is most likely comprised of which of the following types of cells?