Chemistry 6.7 Clinical Endocrinology Flashcards
Which of the following hormones is often decreased by approximately 25% in the serum of pregnant women who have a fetus with Down syndrome?
A. Estriol (E3)
B. Human chorionic gonadotropin (hCG)
C. Progesterone
D. Estradiol (E2)
A. Estriol (E3)
The syndrome of inappropriate antidiuretic hormone secretion (SIADH) causes:
A. Low serum vasopressin
B. Hypernatremia
C. Urine osmolality to be lower than plasma
D. Low serum electrolytes
D. Low serum electrolytes
Select the hormone which when elevated is associated with galactorrhea, pituitary adenoma, and amenorrhea.
A. Estradiol
B. Progesterone
C. Follicle-stimulating hormone (FSH)
D. Prolactin
D. Prolactin
Zollinger-Ellison (Z-E) syndrome is characterized by great (e.g., 20-fold) elevation of:
A. Gastrin
B. Cholecystokinin
C. Pepsin
D. Glucagon
A. Gastrin
Which statement about multiple endocrine neoplasia (MEN) is true?
A. It is associated with hyperplasia or neoplasia of at least two endocrine organs
B. Insulinoma is always present when the pituitary is involved
C. It is inherited as an autosomal recessive disorder
D. Plasma hormone levels from affected organs are elevated at least 10-fold
A. It is associated with hyperplasia or neoplasia of at least two endocrine organs
Select the main estrogen produced by the ovaries and used to evaluate ovarian function.
A. E3
B. E2
C. Epiestriol
D. Hydroxyestrone
B. E2
Which statement best describes the relationship between luteinizing hormone (LH) and FSH in cases of dysmenorrhea?
A. Both are usually increased when there is pituitary adenoma
B. Increases in both hormones and a decrease in estrogen signal a pituitary cause of ovarian failure
C. Both hormones normally peak 1 to 2 days before ovulation
D. In menopause, the LH level at the midcycle peak is higher than the level of FSH
C. Both hormones normally peak 1 to 2 days before ovulation
When pituitary adenoma is the cause of decreased estrogen production, an increase of which hormone is most frequently responsible?
A. Prolactin
B. FSH
C. LH
D. Thyroid-stimulating hormone (TSH)
A. Prolactin
Which set of results is most likely in an adult male with primary testicular failure?
A. Increased LH, FSH, and decreased testosterone
B. Decreased LH, FSH, and testosterone
C. Decreased testosterone, androstenedione, and FSH
D. Increased androstenedione, decreased testosterone, and normal FSH
A. Increased LH, FSH, and decreased testosterone
When should progesterone be measured when evaluating an adult female for anovulation?
A. At the onset of menses
B. During the first 7 days of the menstrual cycle
C. At the midcycle just after LH peaks
D. At the end of the menstrual cycle
C. At the midcycle just after LH peaks
A female with severe excessive pubic and facial hair growth (hirsutism) should be tested for which of the following hormones?
A. Estrogen and progesterone
B. Chorionic gonadotropin
C. Growth hormone
D. Testosterone and dehydroepiandrosterone sulfate
D. Testosterone and dehydroepiandrosterone sulfate
Which set of results is most likely in a female with hypogonadotropic ovarian failure?
A. Increased LH, FSH, and estrogen
B. Decreased LH, FSH, and estrogen
C. Decreased prolactin and estrogen
D. Increased LH and FSH, and decreased estrogen
B. Decreased LH, FSH, and estrogen
The onset of menopause is usually associated with what hormonal changes?
A. Decreased estrogen, testosterone, and androgens
B. Decreased estrogen, FSH, LH, and progesterone
C. Decreased estrogen and progesterone, and increased LH and FSH
D. Decreased estrogen and progesterone, normal LH and FSH
C. Decreased estrogen and progesterone, and increased LH and FSH
Which of the following statements is correct in assessing GH deficiency?
A. Pituitary failure may involve one, several, or all adenohypophyseal hormones; but GH deficiency is usually found
B. A normal random serum level of GH in a child under 6 years old rules out GH deficiency
C. Administration of arginine, insulin, or glucagon will suppress GH release
D. GH levels in the blood show little variation within a 24-hour period
A. Pituitary failure may involve one, several, or all adenohypophyseal hormones; but GH deficiency is usually found
Which statement best describes the level of GH in patients with pituitary adenoma associated with acromegaly?
A. The fasting GH level is always elevated at least twofold
B. Some patients will require a glucose suppression test to establish a diagnosis
C. A normal fasting GH level rules out acromegaly
D. Patients produce a lower concentration of insulin-like growth factor I (IGF-1) than expected from their GH level
B. Some patients will require a glucose suppression test to establish a diagnosis
Hyperparathyroidism is most consistently associated with:
A. Hypocalcemia
B. Hypocalciuria
C. Hypophosphatemia
D. Metabolic alkalosis
C. Hypophosphatemia
Which statement regarding the use of PTH is true?
A. Determination of serum PTH level is the best screening test for disorders of calcium metabolism
B. PTH levels differentiate primary and secondary causes of hypoparathyroidism
C. PTH levels differentiate primary and secondary causes of hypocalcemia
D. PTH levels are low in patients with pseudohypoparathyroidism
C. PTH levels differentiate primary and secondary causes of hypocalcemia
The best method of analysis for serum PTH involves using antibodies that react with:
A. The amino-terminal fragment of PTH
B. The carboxy-terminal end of PTH
C. The amino-terminal and either C-middle or C-terminal fragment
D. All fragments of PTH as well as intact hormone
C. The amino-terminal and either C-middle or C-terminal fragment
Which of the following is most often elevated in hypercalcemia associated with malignancy?
A. Parathyroid-derived PTH
B. Ectopic PTH
C. PTHRP
D. Calcitonin
C. PTHRP
Which is normally the most abundant corticosteroid hormone secreted by the adrenal cortex?
A. Cortisol
B. Dehydroepiandrosterone
C. Aldosterone
D. Corticosterone
A. Cortisol
Which of the following statements regarding adrenal cortical dysfunction is true?
A. Patients with Cushing syndrome usually have hyperkalemia
B. Cushing syndrome is associated with glucose intolerance
C. Addison disease is associated with hypernatremia
D. Addison disease is caused by elevated levels of cortisol
B. Cushing syndrome is associated with glucose intolerance
Which of the following statements about cortisol in Cushing syndrome is true?
A. Twenty-four–hour urinary free cortisol is a more sensitive test than plasma total cortisol
B. Patients with Cushing disease show pronounced diurnal variation in serum cortisol
C. Free cortisol is increased by a high-serum cortisol-binding protein concentration
D. An elevated serum total cortisol level is diagnostic of Cushing syndrome
A. Twenty-four–hour urinary free cortisol is a more sensitive test than plasma total cortisol
Which of the following conditions is characterized by primary hyperaldosteronism caused by adrenal adenoma, carcinoma, or hyperplasia?
A. Cushing syndrome
B. Addison disease
C. Conn syndrome
D. Pheochromocytoma
C. Conn syndrome
Which of the following is the most common cause of Cushing syndrome?
A. Pituitary adenoma
B. Adrenal hyperplasia
C. Overuse of corticosteroids
D. Ectopic adrenocorticotropic hormone (ACTH) production by tumors
C. Overuse of corticosteroids
Which of the following is the mechanism causing Cushing disease?
A. Excess secretion of pituitary ACTH
B. Adrenal adenoma
C. Treatment with corticosteroids
D. Ectopic ACTH production by tumors
A. Excess secretion of pituitary ACTH
In which situation is the plasma or 24-hour urinary cortisol not consistent with the clinical picture?
A. In pregnant patients
B. In patients with a positive result on the overnight dexamethasone suppression test
C. In congenital adrenal hyperplasia
D. In Cushing syndrome caused by ectopic ACTH-producing tumors
C. In congenital adrenal hyperplasia
Which test is used to distinguish Cushing disease (pituitary Cushing) from Cushing syndrome caused by adrenal tumors?
A. Low-dose overnight dexamethasone suppression
B. Inferior petrosal sinus sampling
C. Serum ACTH
D. 24-hour urine free cortisol
C. Serum ACTH
Which is the most widely used screening test for Cushing syndrome?
A. Overnight low-dose dexamethasone suppression test
B. Corticotropin-releasing hormone (CRH) stimulation test
C. Inferior petrosal sinus sampling
D. Metyrapone stimulation test
A. Overnight low-dose dexamethasone suppression test
Which test is the most specific for establishing a diagnosis of Cushing disease (pituitary Cushing)?
A. Low-dose dexamethasone suppression
B. High-dose dexamethasone suppression
C. 24-hour urine free cortisol
D. Petrosal sinus sampling after CRH stimulation
D. Petrosal sinus sampling after CRH stimulation
Which of the following statements about the diagnosis of Addison disease is true?
A. Patients with primary Addison disease show a normal response to ACTH stimulation
B. Primary and secondary Addison disease can often be differentiated by plasma ACTH
C. 24-hour urinary free cortisol is normal in Addison disease
D. Pituitary ACTH reserves are normal in secondary Addison disease
B. Primary and secondary Addison disease can often be differentiated by plasma ACTH
Which of the following statements regarding the catecholamines is true?
A. They are derived from tryptophan
B. They are produced by the zona glomerulosa of the adrenal cortex
C. Plasma levels show both diurnal and pulsed variation
D. They are excreted in urine primarily as free catecholamines
C. Plasma levels show both diurnal and pulsed variation
Catecholamines—epinephrine, norepinephrine, and dopamine—are produced from the amino acid tyrosine by the chromaffin cells of the adrenal medulla. Plasma and urinary catecholamines are measured to diagnose pheochromocytoma. Symptoms include hypertension, headache, sweating, and other endocrine involvement. Plasma catecholamines are oxidized rapidly to metanephrines and VMA; only about 2% is excreted as free catecholamines. The zona glomerulosa is the outermost portion of the adrenal cortex, where aldosterone is mainly produced. Cortisol is made in the zona fasciculata.
Which assay is considered the best single screening test for pheochromocytoma?
A. Total urinary catecholamines
B. VMA
C. HVA
D. Plasma free metanephrines
D. Plasma free metanephrines
Which metabolite is most often increased in carcinoid tumors of the intestine?
A. 5-Hydroxyindolacetic acid (5-HIAA)
B. 3-Methoxy-4-hydroxyphenylglycol (MHPG)
C. 3-Methoxydopamine
D. Homovanillic acid
A. 5-Hydroxyindolacetic acid (5-HIAA)
Which statement regarding the measurement of urinary catecholamines is true?
A. An increased excretion of total urinary catecholamines is specific for pheochromocytoma
B. Twenty-four–hour urinary catecholamine assay avoids pulse variations associated with measurement of plasma catecholamines
C. Total urinary catecholamine measurement provides greater specificity than measurement of urinary free fractionated catecholamines
D. Total urinary catecholamines are not affected by exercise
B. Twenty-four–hour urinary catecholamine assay avoids pulse variations associated with measurement of plasma catecholamines
Which method is most often used to measure fractionated catecholamines (epinephrine, norepinephrine, and dopamine)?
A. Measurement of fluorescence following oxidation by potassium ferricyanide
B. Measurement by HPLC with electrochemical detection
C. Measure of radioactivity after conversion by catechol-O-methyltransferase (COMT) to tritiated metanephrines
D. Measurement by immunoassay
B. Measurement by HPLC with electrochemical detection
Which statement about sample collection for catecholamines and metabolites is true?
A. Blood for catecholamines is collected in the usual manner following a 12-hour fast
B. Twenty-four–hour urine for VMA, catecholamines, or metanephrines is collected in 1 mL of boric acid
C. Twenty-four–hour urine creatinine should be measured with VMA, HVA, or metanephrines
D. There is no need to discontinue medications if a 24-hour urine collection is used
C. Twenty-four–hour urine creatinine should be measured with VMA, HVA, or metanephrines
Which of the following statements applies to measurement of both VMA and metanephrines in urine?
A. Both can be oxidized to vanillin and measured at 360 nm without interference from dietary compounds
B. Both can be measured immunochemically after hydrolysis and derivatization
C. Both require acid hydrolysis prior to measurement
D. Both can be measured by specific HPLC and MS assays
D. Both can be measured by specific HPLC and MS assays
Urinary HVA is most often assayed to detect:
A. Pheochromocytoma
B. Neuroblastoma
C. Adrenal medullary carcinoma
D. Psychiatric disorders, such as manic depression
B. Neuroblastoma
Thyroid hormones are derived from the amino acid:
A. Phenylalanine
B. Methionine
C. Tyrosine
D. Histidine
C. Tyrosine
Which statement regarding thyroid hormones is true?
A. Circulating levels of T3 and T4 are about equal
B. T3 is about 10-fold more active than T4
C. The rate of formation of monoiodotyrosine and diiodotyrosine is about equal
D. Most of the T3 present in plasma is from its direct release from thyroid storage sites
B. T3 is about 10-fold more active than T4
Which of the following statements regarding thyroid hormones is true?
A. Both protein-bound and free triiodothyronine (T3) and thyroxine (T4) are physiologically active
B. Total T3 and T4 are influenced by the level of thyroxine-binding globulin
C. Variation in thyroxine-binding protein levels affects both free T3 and T4
D. An elevated serum total T4 and T3 is diagnostic of hyperthyroidism
B. Total T3 and T4 are influenced by the level of thyroxine-binding globulin
Which of the following conditions will increase total T4 by increasing thyroxine-binding globulin (TBG)?
A. Acute illness
B. Anabolic steroid use
C. Nephrotic syndrome
D. Pregnancy or estrogens
D. Pregnancy or estrogens
Select the most appropriate single screening test for thyroid disease.
A. Free T4 index
B. Free T3
C. Free T4
D. TSH assay
D. TSH assay
The serum TSH level is almost absent in:
A. Primary hyperthyroidism
B. Primary hypothyroidism
C. Secondary hyperthyroidism
D. Euthyroid sick syndrome
A. Primary hyperthyroidism
Which assay is used to confirm difficult cases of hypothyroidism?
A. Free T3 assay
B. Free T4 index
C. Thyrotropin-releasing hormone (TRH) stimulation test
D. TBG assay
C. Thyrotropin-releasing hormone (TRH) stimulation test
Which of the following statements is true regarding reverse T3 (rT3)?
A. Formed in blood by degradation of T4
B. Physiologically active, but less than T3
C. Decreased in euthyroid sick syndrome
D. Interferes with the measurement of serum T3
A. Formed in blood by degradation of T4
A patient has an elevated serum-free T3 and free T4 and undetectable TSH. What is the MOST likely cause of these results?
A. Primary hyperthyroidism
B. Secondary hyperthyroidism
C. Euthyroid with increased TBG
D. Euthyroid sick syndrome
A. Primary hyperthyroidism
A serum thyroid panel reveals an increase in total T4, normal TSH, and normal free T4. What is the MOST likely cause of these results?
A. Primary hyperthyroidism
B. Secondary hyperthyroidism
C. Euthyroid with increased TBG
D. Subclinical hypothyroidism
C. Euthyroid with increased TBG
Which statement about TSH and T4 in early pregnancy is correct?
A. TSH and thyroid hormones fall
B. TSH falls and thyroid hormones rise
C. TSH and thyroid hormones both rise
D. TSH rises and thyroid hormones fall
B. TSH falls and thyroid hormones rise
In which case might a very low plasma TSH result not correlate with thyroid status?
A. Euthyroid sick syndrome
B. Congenital hypothyroidism
C. When TBG is elevated
D. After high-dose corticosteroid treatment
D. After high-dose corticosteroid treatment
