Inflammatory markers in laboratory testing — MCQs

Myeloperoxidase (MPO) is a heme-containing molecule that is found in the azurophilic granules of neutrophils. Upon release, the enzyme catalyzes hypochlorous acid production during the phagocytic response. In the setting of pneumonia, which of the following clinical findings is most directly associated with myeloperoxidase activity?

A 27-year-old male presents to his primary care physician complaining of pain with urination and eye redness. He reports that he developed these symptoms approximately one week ago. He also has noticed left knee and right heel pain that started a few days ago. He denies any recent trauma. He had an episode of abdominal pain and diarrhea ten days ago that resolved. He has otherwise felt well. On exam, he walks with a limp and his conjunctivae are erythematous. Laboratory findings are notable for an elevated erythrocyte sedimentation rate (ESR) and elevated C-reactive protein (CRP). Which of the following is most likely associated with this patient’s condition?

A medical examiner was called to investigate the death of a 75-year-old type 1 diabetic Caucasian male who was a retired physician. His caretaker discovered his body in the bedroom with an empty syringe and a small bottle of lispro lying on the nightstand. She explains that his wife of 50 years passed away six months ago and that he had no children or family. He had become extremely depressed and did not want to live anymore. Which of the following would be most consistent with his blood chemistry if a blood sample were taken?

A 70-year-old woman is evaluated for muscle pain and neck stiffness that has been progressing for the past 3 weeks. She reports that the neck stiffness is worse in the morning and gradually improves throughout the day. She feels fatigued, although there have not been any changes in her daily routine. Her past medical history includes coronary artery disease for which she takes a daily aspirin. Both of her parents died in their 80s from cardiovascular disease. Her blood pressure is 140/90 mm Hg, heart rate is 88/min, respiratory rate is 15/min, and temperature is 37.9°C (100.2°F). On further examination, the patient has difficulty standing up from a seated position, although muscle strength is intact. What is the best next step in management?

You conduct a medical research study to determine the screening efficacy of a novel serum marker for colon cancer. The study is divided into 2 subsets. In the first, there are 500 patients with colon cancer, of which 450 are found positive for the novel serum marker. In the second arm, there are 500 patients who do not have colon cancer, and only 10 are found positive for the novel serum marker. What is the overall sensitivity of this novel test?

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 29-year-old woman comes to the clinic for complaints of fatigue and palpitations for the past 3 days. She reports that even standing up and walking around takes “a lot of energy.” She was forced to call in sick today to her work as a kindergarten teacher. She denies any previous episodes but does endorse symmetric joint pain of her hands, wrists, knees, and ankles that was worse in the morning over the past week that self-resolved. She also reports a runny nose and congestion. Past medical history is unremarkable. Physical examination demonstrates splenomegaly, pallor, and generalized weakness; there is no lymphadenopathy. What is the most likely explanation for this patient’s symptoms?

A 36-year-old woman presents with thyroid swelling. She has been healthy until now and follows all the healthcare precautions except for missing a flu shot this year. On physical examination, the thyroid gland is diffusely enlarged and tender to palpation. Laboratory findings show a decreased serum TSH level and elevated erythrocyte sedimentation rate. Which of the following histopathologic findings would most likely be found in the thyroid gland of this patient?

An otherwise healthy 42-year-old man undergoes routine investigations prior to blood donation. His complete blood count is shown: Hemoglobin 9.3 g/dL Mean corpuscular volume (MCV) 71 μm3 Mean corpuscular hemoglobin (MCH) 21 pg/cell White blood cell count 8,200/mm3 Platelet count 317,000/mm3 Iron studies are shown: Serum iron 210 μg/dL Serum ferritin 310 ng/mL Total iron binding capacity (TIBC) 290 μg/dL Transferrin saturation 78% He occasionally drinks alcohol and denies smoking or use of illicit drugs. There is a family history of anemia including his brother and maternal uncle. Examination shows conjunctival pallor, but is otherwise unremarkable. Which of the following is the most likely diagnosis?

A 55-year-old man comes to the physician for a routine health visit. He feels well except for occasional left-sided abdominal discomfort and left shoulder pain. He has smoked 1 pack of cigarettes daily for 20 years. He does not drink alcohol. His pulse is 85/min and his blood pressure is 130/70 mmHg. Examination shows a soft, nontender abdomen. The spleen is palpated 5 cm below the costal margin. There is no lymphadenopathy present. The remainder of the examination shows no abnormalities. Laboratory studies show: Hemoglobin 12.2 g/dL Hematocrit 36 % Leukocyte count 34,000/mm3 Platelet count 450,000/mm3 Cytogenetic testing of his blood cells is pending. Further evaluation of this patient is most likely to show which of the following findings?