Endocrine system (thyroid, adrenal, pancreas) Practice Questions

Question 1

A scientist in Chicago is studying a new blood test to detect Ab to EBV with increased sensitivity and specificity. So far, her best attempt at creating such an exam reached 82% sensitivity and 88% specificity. She is hoping to increase these numbers by at least 2 percent for each value. After several years of work, she believes that she has actually managed to reach a sensitivity and specificity much greater than what she had originally hoped for. She travels to China to begin testing her newest blood test. She finds 2,000 patients who are willing to participate in her study. Of the 2,000 patients, 1,200 of them are known to be infected with EBV. The scientist tests these 1,200 patients' blood and finds that only 120 of them tested negative with her new exam. Of the patients who are known to be EBV-free, only 20 of them tested positive. Given these results, which of the following correlates with the exam's specificity?

Accepted Answer

98%

Answer

82%

Answer

90%

Answer

84%

Answer

86%

Question 2

A 42-year-old man who is employed as a construction worker presents to his primary care physician with complaints of moderate headaches and profuse sweating. He reports the need to carry up to 3 additional shirt changes to work because they drench quickly even with tasks of low physical exertion. His coworkers have commented about his changing glove and boot sizes, which have increased at least 4 times since he joined the company 10 years ago. Physical examination is unremarkable except for blood pressure of 160/95 mm Hg, hyperhidrosis, noticeably large pores, hypertrichosis, widely spaced teeth, and prognathism. Which of the following best explains the patient’s clinical manifestations?

Accepted Answer

Increased serum insulin-like growth factor 1 (IGF-1)

Answer

Increased serum cortisol

Answer

Increased thyroid-stimulating hormone

Answer

Increased serum metanephrines

Answer

Increased serum testosterone

Question 3

A 15-year-old female presents to her family physician for an annual school physical exam and check-up. She is accompanied by her mother to the visit and is present in the exam room. The patient has no complaints, and she does not have any past medical problems. She takes no medications. The patient reports that she remains active, exercising 5 times a week, and eats a healthy and varied diet. Which of the following would be the best way for the physician to obtain a more in-depth social history, including sexual history and use of alcohol, tobacco, or recreational drugs?

Accepted Answer

Ask the mother to step outside into the hall for a portion of the visit

Answer

Disallow the mother to be present in the examination room throughout the entirety of the visit

Answer

Give the patient a social history questionnaire to fill out in the exam room

Answer

Ask the patient the questions directly, with her mother still in the exam room

Answer

Speak softly to the patient so that the mother does not hear and the patient is not embarrassed

Question 4

A 60-year-old man comes to the emergency department because of recurrent episodes of fatigue, palpitations, nausea, and diaphoresis over the past 6 months. The episodes have become more frequent in the last 2 weeks and he has missed work several times because of them. His symptoms usually improve after he drinks some juice and rests. He has had a 2-kg (4.5-lb) weight gain in the past 6 months. He has a history of bipolar disorder, hypertension, and asthma. His sister has type 2 diabetes mellitus and his mother has a history of medullary thyroid carcinoma. His medications include lithium, hydrochlorothiazide, aspirin, and a budesonide inhaler. His temperature is 36.3°C (97.3°F), pulse is 92/min and regular, respirations are 20/min, and blood pressure is 118/65 mm Hg. Abdominal examination shows no abnormalities. Serum studies show:
Na+ 145 mEq/L
K+ 3.9 mEq/L
Cl- 103 mEq/L
Calcium 9.2 mg/dL
Glucose 88 mg/dL
Which of the following is the most appropriate next step in diagnosis?

Accepted Answer

72-hour fasting test

Answer

Corticotropin stimulation test

Answer

Water deprivation test

Answer

Oral glucose tolerance test

Answer

24-hour urine catecholamine test

Question 5

An investigator is studying a drug that acts on the thyroid hormone pathway. Levels of serum free T3 and T4 in healthy participants are measured before and after administration of the drug. After administration, there is a decrease in the average serum free T3 level, while the average serum free T4 level is increased compared to initial serum studies. Inhibition of which of the following is the most likely mechanism of action of this drug?

Accepted Answer

Peripheral 5'-deiodinase

Answer

Thyroid-stimulating hormone

Answer

Follicular iodotyrosine deiodinase

Answer

Follicular thyroid peroxidase

Answer

Follicular thyroid proteases

Question 6

A 40-year-old woman visits her physician’s office with her husband. Her husband says that she has been complaining of recurring headaches over the past few months. A year ago she was diagnosed with diabetes and is currently on treatment for it. About 6 months ago, she was diagnosed with high blood pressure and is also taking medication for it. Her husband is concerned about the short span during which she has been getting all these symptoms. He also says that she occasionally complains of changes and blurring in her vision. In addition to all these complaints, he has observed changes in her appearance, more prominently her face. Her forehead and chin seem to be protruding more than usual. Suspecting a hormonal imbalance, which of the following initial tests would the physician order to indicate a possible diagnosis?

Accepted Answer

Serum insulin-like growth factor-1 (IGF-1)

Answer

Chest X-ray

Answer

Pituitary magnetic resonance image (MRI)

Answer

Serum growth hormone

Answer

Glucose suppression test

Question 7

A 43-year-old woman comes to the physician for an annual health maintenance examination. On questioning, she has had fatigue and headaches for the last month. A few weeks ago, she had to have her wedding ring resized because it had become too small for her finger. She has mild persistent asthma and anxiety disorder. She drinks 2–3 glasses of red wine per night and has smoked one pack of cigarettes daily for 16 years. She works a desk job in accounting and has recently been working long hours due to an upcoming company merger. Her father has a history of a pituitary adenoma. Current medications include alprazolam, a fluticasone inhaler, and an albuterol inhaler. She is 160 cm (5 ft 3 in) tall and weighs 81.6 kg (180 lb); her BMI is 32 kg/m2. Her temperature is 37.2°C (99°F), pulse is 92/min, and blood pressure is 132/80 mm Hg. Examination shows no abnormalities. Fasting laboratory studies show:
Hemoglobin 13 g/dL
Serum
Na+ 135 mEq/L
K+
4.6 mEq/L
Cl- 105 mEq/L
HCO3- 22 mEq/L
Urea nitrogen 17 mg/dL
Glucose 160 mg/dL
Creatinine 0.9 mg/dL
Which of the following is the most likely underlying mechanism of this patient's hyperglycemia?

Accepted Answer

Insulin resistance

Answer

Decreased insulin production

Answer

Adverse effect of medication

Answer

Stress

Answer

Hypersecretion of ACTH

Question 8

Certain glucose transporters that are expressed predominantly on skeletal muscle cells and adipocytes are unique compared to those transporters found on other cell types within the body. Without directly affecting glucose transport in other cell types, which of the following would be most likely to selectively increase glucose uptake in skeletal muscle cells and adipocytes?

Accepted Answer

Increased levels of circulating insulin

Answer

Increased plasma glucose concentration

Answer

It is physiologically impossible to selectively increase glucose uptake in specific cells

Answer

Decreased plasma glucose concentration

Answer

Decreased levels of circulating insulin

Question 9

A 56-year-old male comes to the physician because of a 2-month history of excessive sleepiness. He reports that he has been sleeping for an average of 10 to 12 hours at night and needs to take multiple naps during the day. Six months ago, he was diagnosed with small cell lung carcinoma and underwent prophylactic cranial irradiation. This patient's symptoms are most likely caused by damage to which of the following structures?

Accepted Answer

Suprachiasmatic nucleus

Answer

Subthalamic nucleus

Answer

Ventromedial nucleus

Answer

Preoptic nucleus

Answer

Supraoptic nucleus

Question 10

A 60-year-old man with type 2 diabetes on metformin and insulin presents with 3 days of nausea, vomiting, and diffuse abdominal pain. He appears ill and confused. Vital signs: BP 95/60 mmHg, HR 115/min, RR 28/min, T 37.2°C. Labs show glucose 380 mg/dL, pH 7.28, HCO3 18 mEq/L, anion gap 24, serum osmolality 310 mOsm/kg, negative urine ketones, creatinine 2.8 mg/dL (baseline 1.1), lactate 8.2 mmol/L. Apply physiological principles to determine the primary acid-base and metabolic disturbance.

Accepted Answer

Hyperosmolar hyperglycemic state complicated by lactic acidosis from metformin

Answer

Sepsis-induced lactic acidosis with stress hyperglycemia

Answer

Alcoholic ketoacidosis with concurrent diabetic emergency

Answer

Diabetic ketoacidosis with renal failure from volume depletion

Answer

Mixed metabolic acidosis from uremia and starvation ketosis

Endocrine system (thyroid, adrenal, pancreas)

Study Resources

Lessons

Questions

Flashcards

Lessons

Hypothalamic-pituitary axis

Thyroid hormone synthesis

Thyroid hormone transport and action

Regulation of thyroid function

Glucocorticoid synthesis and regulation

Mineralocorticoid actions

Adrenal medulla and catecholamines

Pancreatic endocrine function

Insulin secretion and action

Glucagon physiology

Glucose homeostasis mechanisms

Endocrine feedback systems

Integration of metabolic regulation

Practice Questions

Flashcards

About Endocrine system (thyroid, adrenal, pancreas) for USMLE

Lessons in Endocrine system (thyroid, adrenal, pancreas)

Master Endocrine system (thyroid, adrenal, pancreas)