Endocrine Disorders Flashcards
T/F When carcinomas cannot be histologicially distinguished from adenomas, the only sure sign of malignancy is metastasis.
1
True; We see this, for example, with the parathyroid glands.
____________________________ syndrome refers to the unregulated secretion of hormones and hormone-like compounds from tumors
- Paraneoplastic
T/F The posterior pituitary hormones are prolactin and ACTH.
- False; ACTH and prloactin are anterior pituitary hormones. The posterior pituitary hormones are ADH and oxytocin.
T/F Neurohormones released by the posterior pituitary are not synthesized in the posterior pituitary.
- True; They are synthesized by neurons whose cell bodies lie in the hypothalamus.
T/F Neurohormones released by the anterior pituitary are not synthesized in the anterior pituitary.
- False; Anterior pituitary hormones are synthesized by ant. pituicytes (ant. pituitary cells) -under the regulation of hypothalamic releasing hormones.
T/F Continual stimulation of the adrenal medulla by ACTH would lead to hyperplasia of the adrenal medulla
- False; The adrenal medullary cells do not express ACTH receptors on their surfaces. They are thus oblivious to ACTH and would not respond to it at all.
T/F Continual stimulation of the adrenal cortex by ACTH would lead to adrenocortical hyperplasia
- True; ACTH does indeed stimulate the adrenal cortex- esp. the zona fasiculata that makes cortisol; Continual ACTH stimulation of the cortex would indeed lead to adrenocortical hyperplasia. There is a similar relationship between the follicular cells of the thyroid and TSH.
The [anterior/ posterior] pituitary is also known as the adenohypophysis.
- anterior; The anterior pituitary is a gland (‘adeno-‘) derived from the oral mucosa.
The [anterior / posterior] pituitary is also known as the neurohypophysis.
- posterior; The posterior pituitary is derived from the neural tissue (‘neuro-‘) of the hypothalamus.
The [anterior/ posterior] pituitary is derived from epithelial cells in the mouth region which migrate upward in the head.
- anterior
The connection between the hypothalamus and the [anterior/ posterior] pituitary gland is mainly a vascular one.
- anterior
The connection between the hypothalamus and the [anterior/ posterior] pituitary gland is mainly a neural one.
- posterior
The ________________________ is the stalk of the pituitary gland.
- infundibulum
___________________ is a control loop whereby the product or output of a system acts back on the system to repress or stop its own production.
14
Negative feedback, or feedback inhibition
The _________________________, a region of the brain, largely controls the secretion of hormones by the anterior pituitary.
- hypothalamus
A(n) ___________________ hormone regulates the hormonal functioning of a distant endocrine gland.
- tropic
____________ is the hypothalamic hormones that controls the release of TSH by the anterior pituitary.
- TRH, or Thyrotropin Releasing Hormone
_________________ is the hypothalamic hormones that controls the release of FSH and LH by the anterior pituitary.
- GnRH, or Gonadotropin Releasing Hormone
______________ is the hypothalamic hormones that controls the release of ACTH by the anterior pituitary.
- CRH, or Corticotropin Releasing Hormone
T/F Laron dwarfism is easily treated in children by administration of growth hormone.
- False; Recall that Laron hormone is due to insensitivity of the growth hormone receptor. Therefore, supplying exogenous growth hormone will do little to overcome that deficiency. But growth hormone is tropic in that it elecits the release of
somatomedin (mostly from liver cells), and it is somatomedin that actually stimulates growth in stature. Thus administration of somatomedin, not growth hormone, will bypass the receptor deficiencies of Laron dwarfism and cause growth of long bones.
________________________ refers to the deficient secretion of one or more of the hormones secreted by the pituitary.
- Hypopituitarism
______________________ refers to total failure of pituitary function; no pituitary hormones are being secreted.
- Panhypopituitarism
____________________, or ischemic necrosis of the pituitary, usually is caused by hypotension secondary to postpartum hemorrhage.
- Sheehan syndrome
In children, ___________________ results from the inadequate secretion of growth hormone.
- pituitary dwarfism
____________________ refers to a condition marked by short statue due to extreme insensitivity of the growth hormone receptor to growth hormone.
- Laron dwarfism
Which ONE of the following is not a classic symptom of panhypopituitarism?
A. General weakness B. Heat intolerance C. Poor appetite D. Weight loss E. Hypotension F. Amenorrhea and impotence G. In men, loss of muscle mass, and facial and pubic hair H. Pallor I. (None. All of the above are typical symptoms of panhypopituitarism)
B. Panhypopituitarism produces cold intolerance. The loss of TSH also causes low serum T3 and T4. Since these control the metabolic rate, in their absence, a person does not produce much body heat and feels chilled all the time. In other words, they cannot tolerate chilly temperatures because they are not producing enough internal heat. Note that the lack of T3 and T4 also account for the general weakness, poor appetite, weight loss, and hypotension (remember that T3 and T4 increase sympathetic influence, so in their absence…).
T/F Pituitary adenomas are about three times more common in women than in men.
- False; Pituitary adenomas are actually most common in middle-aged men.
T/F Although the pituitary gland is composed of several populations of pituicytes, each secreting their own set or sets of hormones, a functional pituitary adenoma usually only secretes one hormone.
- True; for example, a prolactinoma arises from the lactotropic pituicytes and only secretes prolactin.
T/F In pre-pubertal patients, somatotropic adenomas result in pituitary dwarfism.
- False; A somatotropic adenoma would secrete high levels of growth hormone and thus cause gigantism, not dwarfism.
T/F In post-pubertal patients, somatotropic adenomas result in acromegaly.
- True; Remember that with high levels of growth hormone, the growth extends to the soft organs as well, such that cardiomegaly is common.
[Lactotropic/ Somatotropic / Thyrotropic / Corticotropic] adenomas secrete prolactin.
- Lactotropic, otherwise known as a prolactinoma.
[Lactotropic/ Somatotropic / Thyrotropic / Corticotropic] adenomas secrete ACTH.
- Corticotropic
Cushing [disease/ syndrome ] refers to hypercortisolism produced by a corticotropic adenoma of the pituitary.
- Cushing disease. The name is specifically reserved to the hypercortisolism due to a prolactinoma; all other types of hypercortisolism are refered to as Cushing syndrome.
_____________________ are benign neoplasms of the anterior lobe of the pituitary and are often associated with excess secretion of pituitary hormones and evidence of corresponding
endocrine hyperfunction.
- Pituitary adenomas
A _____________________ is a common name for a lactotropic adenoma.
- prolactinoma
________________, a dopamine analog, can suppress the secretion of prolactin from a prolactinoma.
- Bromocriptine; Recall that PIF- prolactin inhibitory factor- is dopamine, and bromocriptine is a dopamine analog (agonist).
Which ONE of the following is not a typical mass effect produced by pituitary adenomas?
A. Bitemporal hemianopsia B. Oculomotor palsy C. Bell palsy D. Severe headache E. Hypothalamic dysfunction F. (None. All of the above are typical symptoms resulting from the mass effects of a pituitary adenoma)
- C. Bell palsy, which is probably caused by viral inflammation of the facial nerve.
Which ONE of the following is not a typical symptom of a prolactinoma?
A. Amenorrhea B. Dysfunctional uterine bleeding C. Galactorrhea D. Infertility E. Impotence F. (None. All of the above are typical symptoms of a prolactinoma)
- B. These symptoms of a prolactinoma are easily explained. Galactorrhea results in a woman from the high prolactin levels. Recall that prolactin inhibits the release of LH and FSH by inhibiting the hypothalamic release of GnRH. This results in infertility, amenorrhea, and impotence. DUB is due to high unopposed estrogen levels, a situation we would not see with low FSH and LH.
T/F The treatment for diabetes insipidus may include ADH replacement therapy.
- True; Of course this would be of most benefit to patients with central diabetes insipidus.
A key feature of SIADH is sodium retention and the inability to concentrate the urine.
- False; It’s backwards- the situation described is for diabetes insipidus. In SIADH a patient hypersecretes ADH, so the condition is characterized by the inability to dilute the urine, and sodium loss (natriuresis) resulting in hyponatremia. Also, be careful on the exam- I might flip this question, so it DOES describe SIADH.
T/F A common cause of SIADH is a paraneoplastic small cell carcinoma of the lungs.
- True
T/F The clinical picture of SIADH is dominated by hyponatremia, cerebral edema, and CNS dysfunctions such as headache and vomiting; severe cases may lead to convulsions and coma.
- True
In [central/ nephrogenic] diabetes insipidus, the posterior pituitary secretes insufficient ADH.
- Central
In [central/ nephrogenic] diabetes insipidus, the kidney tubules show insufficient response to circulating ADH.
- nephrogenic
______________________ is a posterior pituitary disorder characterized by the inability to concentrate the urine, with resulting polyuria and polydipsea; the biochemical basis is an insufficient ADH activity.
- Diabetes insipidus
_________________ is a disorder characterized by excessive release ADH from the posterior pituitary gland or another source.
- SIADH, or syndrome of inappropriate ADH secretion
Which ONE of the following is not a common treatment option for SIADH?
A. Long-term fluid restriction
B. IV saline
C. Demeclocycline or tolvaptan
D. (None of the above, i.e., they are all common treatments for SIADH)
- D. Of course, treating any underlying illness would also be part of the treatment plan.
Which ONE of the following is NOT a typical symptom/finding of diabetes insipidus?
A. Intense thirst B. Copious urine output C. Renal calculi D. Lack of sugar in the urine E. (None. All of the above are typical symptoms of diabetes insipidus)
- No renal calculi.
[Iodine / Calcium/ Vitamin D/ Iron / Sulfur / Zinc ] is a chemical element found in the thyroid hormones T3 and T4.
- Iodine
The ____________________________ cells of the thyroid gland are responsible for the production of the thyroid hormones T3 and T4.
- follicular; parafollicular cells produce calcitonin.
____________________ from the anterior pituitary stimulates follicular activity in the thyroid and the release of T3 and T4 hormones.
- TSH; And TSH in turn is regulated by TRH from the hypothalamus.
Which ONE of the following statements is NOT TRUE regarding the thyroid hormones T3 & T4?
A. T3 & T4 are catecholamines
B. T3 & T4 are derived from two molecules of tyrosine
C. T3 & T4 contain three or four iodine molecules
D. T3 & T4 are stored in colloid attached to thyroglobulin
E. T3 has about 10 times more biological activity than T4
F. T4 is converted to T3 in the peripheral tissues (mainly liver) of the body
G. (None. All of the above are true regarding T3 and T4)
- A. Like T3 and T4, catecholamines are also formed from the amino acid tyrosine. However, T3 and T4 are not catecholamines- they do not possess the catechol group.
Which ONE of the following conditions is most likely to lead to a goiter?
A. Secondary hypothyroidism due to failure of the hypothalamus or pituitary gland.
B. Primary hyperthyroidism due to a small but hypersecreting thyroid tumor
C. Secondary hyperthyroidism due to a small but hypersecreting pituitary tumor
- C. In case A, the hypothalamus/pituitary is misbehaving, so that TSH levels will be low. In B, high levels of thyroid hormones will suppress TSH production, so again, TSH levels will be low. In any case, remember my rule-goiters are likely to develop when TSH or TSH-like stimulation is excessive.
T/F Goiters can develop in a setting of hypopituitarism secondary to hypothalamic or anterior pituitary failure.
56A
False
With hypothalamic or anterior pituitary failure, TSH levels will be low. Hence, no goiter.
T/F Thyroid cancer can lead to the production of a goiter.
56B
True
A tumor can enlarge the thyroid and thus cause a goiter.
T/F Goiters will not develop in the absence of TSH overstimulation.
56C
False
While TSH overstimulation is a major cause of goiters, there are other ways they can develop in the absence of elevated TSH levels. Neoplasia and TSI antibodies immediately come to mind.
T/F Lack of dietary iodine may lead hypothyroidism but does not lead to goiter formation.
56D
False
Lack of dietary iodine is a MAJOR cause of goiters worldwide.
T/F Goiters can develop in a setting of hypopituitarism via primary failure of the thyroid itself.
56E
True
Thyroid failure means low T3 and T4 levels, which in turn means high TSH levels and thyroidal overstimulation. Hence, primary thyroid failure can indeed lead to goiter formation.
T/F Goiters can develop in the setting of hyperthyroidism via a functional pituitary adenoma.
56F
True
If the tumor is a thyrotropic adenoma (which secretes TSH) then yes, a goiter may develop.
T/F Goiters can develop in the setting of hyperthyroidism via antibody stimulation of the thyroidal follicular cells.
56G
True
This is precisely the case in Graves disease.
T/F Patients with nontoxic goiter are usually euthyroid.
57
True
T/F For reasons that are unclear, in nontoxic goiter the capacity of the thyroid to produce thyroid hormones is impaired.
58
True
_______________________ refers to an enlargement of the thyroid that is not
associated with functional, inflammatory, or neoplastic alterations
59
Nontoxic goiter; ‘Nontoxic’ means that patients are neither hypothyroid nor hyperthyroid- they are euthyroid. These goiters are not associated with functional disturbances (such as pituitary hypo- or hyper-secretion, there is no evidence of thyroiditis (inflammation), and there is not sign of a thyroid tumor.
T/F Typically, in cases of nontoxic goiter, the ability of the thyroid gland to produce thyroid hormones is impaired, and patients thus develop hypothyroidism.
60A
False
With nontoxic goiters, the ability of the thyroid gland to produce hormone is impaired, but the body compensates (increased thyroid stimulation via TSH) so that a patient usually maintains normal T3 and T4 levels.
T/F Diffuse nontoxic goiters are the early stage of the disease and are most common during pregnancy and in adolescent patients.
60B
True
T/F Diffuse nontoxic goiters often show nodularity.
60C
False
If they showed nodularity, they would be multinodular nontoxic goiters.
T/F Endemic nontoxic goiters occur in a defined region of the world- usually an area that is iodine deficient or an area where people consume large quentities of crops that inhibit thyroid hormone synthesis (e.g., crucifers).
60D
True
Of course, lack of dietary iodine is the MAJOR cause of endemic goiters worldwide.
T/F In diffuse nontoxic goiters, the entire thyroid is enlarged, its follicles hyperplastic and hypertrophic.
60E
True
Thyroid failure means low T3 and T4 levels, which in turn means high TSH levels and thyroidal overstimulation. Hence, primary thyroid failure can indeed lead to goiter formation.
T/F (Diffuse nontoxic) Sporadic goiters are idiopathic.
60F
True
Also, sporadic goiters are more common in women than men, for unknown reasons.
T/F Multinodular nontoxic goiters represent the early stage of the disease and are more common in adolescent patients.
60G
False
T/F Multinodular nontoxic goiters can evolve into hyperthyroidism.
60H
True
These are called toxic multinodular goiters; their hyperthyroidism differs from Graves disease in that toxic multinodular goiters do not produce the infiltrative ophthalmopathy (exophthalmos).
T/F Some multinodular goiters progress to cancer.
60I
True
The frequency of this progression is low (~5%) but not zero.
T/F Nontoxic goiters may cause dysphagia, dyspnea, jugular compression, hoarseness.
60J
True
T/F Exophthalmia is seen in all types of hyperthyroidism.
61
False; It is pathognomonic for Graves disease, and is not seen in other types of hyperthyroidism such as toxic multinodular goiter.
T/F Goiters do not develop in untreated Graves disease.
62
False; In fact, goiters are quite common in untreated Graves disease.
T/F Ironically, the hyperthyroidism of untreated Graves disease may evolve into thyroid failure and hypothyroidism.
63
True; Presumably the constant stimulation and hyperthyroidism overwhelms the gland; it fails and the person lapses into hypothyroidism.
T/F In Graves disease, high T3/T4 levels are accompanied by low TSH levels.
64
True; And important diagnostic results.
T/F In Graves disease, radioactive iodine uptake tests show decreased uptake of iodine by the thyroid gland.
65
False; In graves disease, the thyroid is overactive- it’s going to take up lots of iodine!
T/F A typical course of treatment for Graves disease is (1) administer adrenergic antagonists to alleviate the heightened sympathetic effects, followed by (2) administration of antithyroidal drugs to inhibit T3/T4 release.
66
True
_________________ is a hypermetabolic state caused by elevated circulating levels of free T3 and T4; hyperthyroidism is the most common cause of this condition.
67
Thyrotoxicosis
__________________ is caused by excessive thyroid activity.
68
Hyperthyroidism
_____________ is an autoimmune disorder caused by antibodies that agonistically bind to the surface TSH receptors of the thyroid follicular cells, stimulating them.
69
Graves disease, the most common cause of hyperthyroidism
Circulating antibodies called _______________, or TSIs, are the root cause of Graves disease.
70
thyroid stimulation immunoglobins
____________ is a common antithyroid drug commonly used to treat the hyperthyroidism of Graves disease.
71
Either propylthiouracil or methimazole work here.
Which ONE of the following is NOT a typical symptom of the hyperthyroidism of Graves disease?
A. Tachycardia and cardiac palpitations
B. Diarrhea
C. Pallor and cold, clammy skin
D. Exophthalmos
E. Weight loss and increased appetite
F. Restlessness, nervousness, anxiety, and sweating
G. (None. All of the above are typical symptoms of hyperthyroidism)
71
C. Cold, clammy, pallid skin is typical of hypothyroidism.
T/F In thyrotoxic patients, the skin tends to be cool, dry, and pallid due to decreased peripheral blood flow and vasoconstriction.
72A
False
This is backwards. Remember that high circulating levels of T3/T4 activates the sympathetic nervous system. Sympathetic effect on the skin is vasodilation (to increase heat loss), resulting in warm, soft, moist, and flushed skin.
T/F In thyrotoxic patients, cold intolerance is common.
72B
False
Again, backwards. These patients are producing lots of internal heat, so they have heat intolerance (and would probably welcome cool air around them).
T/F In thyrotoxic patients, tachycardia and palpitations are common.
72C
True
Think sympathetic effects on the body- fast heart beat and palpitations are examples.
T/F In thyrotoxic patients, cardiomegaly and cardiac arrhythmias may develop, and these may lead to congestive heart failure and death.
72D
True
Another cardiac complication is thyrotoxic cardiomyopathy.
T/F Thyrotoxic effects on the nervous system include nervousness, insomnia, and inability to concentrate
72E
True
Again, think sympathetic effects on the body
T/F Constipation is common in thyrotoxic patients
72F
False
Usually the opposite is seen- increased peristalsis resulting in diarrhea.
T/F In thyrotoxic patients, distal muscle weakness but increased muscle mass are common.
72G
False
Again, backwards. In thyrotoxicosis we see proximal muscle weakness and decreased muscle mass.
T/F High T3/T4 levels activates osteoclasts, leading to osteoporosis and hypercalcemia.
72H
True
One effect of the osteoporosis is increased rate of bone fracture.
T/F Untreated infantile hypothyroidism results in permanent mental retardation known as cretinism.
73
True