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Year 2 RE > Endocrinology of Ageing > Flashcards

Endocrinology of Ageing Flashcards

1
Q

What is the normal pathway for thyroid hormones to be secreted by the thyroid gland?

A
  • Thyrotropin-releasing hormone (TRH) released from the hypothalamus
  • TRH signals anterior pituitary gland, releasing thyroid stimulating hormone (TSH)
  • TSH binds to follicular cells of thyroid and triiodothyronine (T3) and thyroxine (T4)
  • T3 and T4 provide negative feedback loop on TRH and TSH levels
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2
Q

In ageing the pituitary gland becomes less responsive. What happens to the anterior pituitary glands sensitivity on:

  • thyroid stimulating hormone (TSH) levels response to thyrotropin releasing hormone (TRH
  • TSH response to low levels of circulating triiodothyronine (T3) and thyroxine (T4)
A
  • anterior pituitary less sensitive to TRH so less TSH released
  • anterior pituitary less sensitive to detect low T3 and T4, so less TSH released
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3
Q

Does the thyroid gland respond in the same way to thyroid stimulating hormone (TSH) as we age?

A
  • no
  • less responsive to TSH
  • smaller response to TSH means less triiodothyronine (T3) and thyroxine (T4)
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4
Q

In ageing we know that the pituitary gland and thyroid gland are less sensitive and therefore we have less triiodothyronine (T3) and thyroxine. However, what happens in the peripheries to T3 and T4?

1 - increased conversion of T4 to T3
2 - increased binding of T3 to albumin in the blood so longer half life
3 - reduced activity of 5’ deiodinase so less T4 converted to T3
4 - less binding of T4 in the blood so more enters the cells

A

3 - reduced activity of 5’ deiodinase so less T4 converted to T3

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5
Q

What is the most common finding in the thyroid as we age?

  • hypothyroidism
  • hyperthyroidism
A
  • hypothyroidism

- thyroid stimulating hormone will increase to try and compensate

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6
Q

The most common finding in the thyroid as we age is hypothyroidism, resulting in increased thyroid stimulating hormone will increase to try and compensate. Is this more common in men or women?

A
  • women

- mainly due to the link between hypothyroidism and autoimmune disease

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7
Q

The most common finding in the thyroid as we age is hypothyroidism, resulting in increased thyroid stimulating hormone to compensate and try to increase T3 and T4, which is more common in women. What are the 2 most common causes of this?

1 - polypharmacy and autoimmune disease
2 - autoimmune disease and surgery
3 - polypharmacy and surgery
4 - surgery and tumour

A

2 - autoimmune disease and surgery
1st = autoimmune is number
2nd = surgical is number

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8
Q

The most common finding in the thyroid as we age is hypothyroidism, resulting in increased thyroid stimulating hormone will increase to try and compensate, which is more common in women. The signs of hypothyroidism in ageing is similar to younger people, but often missed, why?

A
  • symptoms are attributed to ageing process
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9
Q

The most common finding in the thyroid as we age is hypothyroidism, resulting in increased thyroid stimulating hormone will increase to try and compensate, which is more common in women. The signs of hypothyroidism in ageing are similar to younger people. What are the 2 most common symptoms reported by more than 50% of patients?

1 - fatigue and weakness
2 - fatigue and reduced libido
3 - weakness and reduced libido
4 - fatigue and osteoporosis

A

1 - fatigue and weakness

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10
Q

The most common finding in the thyroid as we age is hypothyroidism, resulting in increased thyroid stimulating hormone will increase to try and compensate, which is more common in women. On physical examination what 3 cardiac related aspects may we see?

1 - tachycardia, diastolic hypertension, pericardial effusion
2 - bradycardia, systolic hypertension, pericardial effusion
3 - bradycardia, diastolic hypertension, pericardial effusion
4 - bradycardia, systolic hypertension, pericardial effusion

A

3 - bradycardia, diastolic hypertension, pericardial effusion

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11
Q

The most common finding in the thyroid as we age is hypothyroidism, resulting in increased thyroid stimulating hormone will increase to try and compensate, which is more common in women. On laboratory assessment, what might we expect to see in the levels of thyroid stimulating hormone (TSH) and free thyroxine (FT4)?

A
  • TSH will be elevated as pituitary tries to increase T3 and T4
  • FT4 will be low as less secreted by thyroid
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12
Q

The most common finding in the thyroid as we age is hypothyroidism, resulting in increased thyroid stimulating hormone will increase to try and compensate, which is more common in women. What is the most common treatment for hypothyroidism in elderly patients?

1 - testosterone
2 - polythiouracil
3 - carbimazole
4 - levothyroxine

A

4 - levothyroxine

  • synthetic version of T4)
  • start with a low does with small increments
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13
Q

The most common finding in the thyroid as we age is hypothyroidism, resulting in increased thyroid stimulating hormone will increase to try and compensate, which is more common in women. The most common treatment for hypothyroidism in elderly patients is levothyroxine replacement (synthetic hormone), which are started at low doses. What patients would and would not be able to take the full dose of levothyroxine?

A
  • not full dose = cardiac history
  • full dose = non cardiac history
  • levothyroxine will increase HR and place stress on the heart
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14
Q

How common is hyperthyroidism in elderly populations?

A
  • 0.5%
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15
Q

Hyperthyroidism in elderly populations is not common (0.5%). What are the 3 most common symptoms in elderly patients, which are similar to younger patients?

1 - weight gain, depression, agitation
2 - weight loss, depression, agitation
3 - weight loss, elated, agitation
4 - weight gain, depression, relaxed

A

2 - weight loss, depression, agitation

SIGNS CAN BE SIMILAR TO INCREASED SYMPATHETIC ACTIVITY

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16
Q

Hyperthyroidism in elderly populations is not common (0.5%). What common symptoms can occur that are cardiovascular related in elderly patients?

A
  • atrial fibrillation
  • thrombosis
  • hypertension
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17
Q

Hyperthyroidism in elderly populations is not common (0.5%). What common symptoms can occur that in relation to bones in elderly patients?

A
  • reduced bone mineral density

- increased risk of osteoporosis and fracture

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18
Q

Thyroid nodules are solid or fluid-filled lumps that form within your thyroid, a small gland located at the base of your neck, just above your breastbone. How common as these in elderly patients?

A
  • palpable nodules found in 5% of pts >60
  • autopsy studies show 90% in women >70
  • 50% of women over 50 have nodules
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19
Q

Thyroid cancer is just as common in younger and older patients. Do they have the same survival rates though?

A
  • no
  • women <20y/o = 100% 10 year survival
  • women >60y/o = 5% 10 year survival
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20
Q

Anaplastic refers to the cancer cells that divide rapidly and have little or no resemblance to normal cells. What is anaplastic thyroid cancer?

A
  • aggressive form of thyroid cancer

- characterised by uncontrolled growth of cells in the thyroid gland

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21
Q

Anaplastic refers to the cancer cells that divide rapidly and have little or no resemblance to normal cells. Anaplastic thyroid cancer is an aggressive form of thyroid cancer characterised by uncontrolled growth of cells in the thyroid gland. How common is this and what age is most at risk?

A
  • 1-2% of all thyroid cancers
  • peak incidence in 60’s, and more than 65% occur in patients >65
  • poor survival rates 5 year survival is 7% and mean survival is 11 months
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22
Q

What is Thyroid Lymphoma?

A
  • lymphocytes of the thyroid turn into cancer cells
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23
Q

Thyroid Lymphoma is when lymphocytes of the thyroid turn into cancer cells. How common is this?

A
  • 0.5-5% of all thyroid cancers peaking between 50-80 years old
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24
Q

Androgens are hormones that contribute to growth and reproduction in both men and women, but are at much higher levels in men. Testosterone is one of the most important androgens in males. What happens to testosterone levels as we age?

A
  • levels begin to drop from 30 years
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25
Q

Androgens are hormones that contribute to growth and reproduction in both men and women, but are at much higher levels in men. Testosterone is one of the most important androgens in males. Testosterone levels begin to decline from 30 years of age, which is different to menopause in women. Which group of patients are likely to have lower levels of testosterone?

1 - acute illness
2 - previous trauma to head or neck
3 - chronic illness

A

3 - chronic illness

26
Q

Sex hormone binding globulin (SHBG) controls the amount of testosterone that your body tissues can use, essentially it can be bound to SHBG and no biologically active or unbound to SHBG and be active. What happens to SHBG levels as we age?

A
  • levels increase

- increased SHBG means less biologically active testosterone

27
Q

What is the incidence of low testosterone in men?

A
  • 50% of men >70 y/o

- 3% of healthy men

28
Q

In men with low testosterone, what happens to LH/FSH levels?

1 - increase as no negative feedback loop
2 - increase to inhibit testosterone release
3 - drop as no negative feedback loop
4 - increase due to pituitary adenoma

A

1 - increase as no negative feedback loop

  • low levels of testosterone released from leydig cells
  • BUT lower than expected, indicating loss of negative feedback loop
29
Q

What are some of the common symptoms in men with low testosterone?

A
  • decreased muscle mass and strength
  • decreased bone mineral density
  • decreased libido and sexual functioning
  • increased fat mass
  • anaemia
  • dysthymia (Persistent Depressive Disorder)
30
Q

Can low levels of testosterone affect mortality?

A
  • yes
  • lower testosterone is linked with increased mortality
  • replacement therapy doesn’t appear to correct this
31
Q

Match up the levels of testosterone with the following diagnosis?

  • no deficiency
  • deficient
  • need to check free Testosterone
  • > 350ng/dL
  • <230ng/dL
  • 230-350ng/dL
A
  • > 350 ng/dl = no deficiency
  • <230 ng/dl = deficient
  • 230-350 ng/dl: need to check free Testosterone
32
Q

Although women are not as dependent on testosterone as much as men, what can happen to testosterone levels with women?

A
  • by age 40y/o can be reduced by 50% when compared with levels at 20y/o
  • can be made worse by oophorectomy (removal of 1 or both ovaries)
33
Q

Although women are not as dependent on testosterone as much as men, their testosterone levels will decrease. Are women generally provided with testosterone replacement?

A
  • no
34
Q

Although men require testosterone, are they generally prescribed testosterone when their levels drop as per ageing?

A
  • no

- generally only prescribed unless levels are consistently low

35
Q

What are some of the basic functions of growth hormone?

A
  • similar properties to sex steroids
  • improve lean body mass and muscle strength
  • decrease fat mass
  • improve BMD
  • improve sense of well being
    GROWTH HORMONE DEFICIENCY DOES THE OPPOSITE
36
Q

What happens to growth hormone levels as we age?

A
  • decline with age
37
Q

What other hormones can have a significant affect on growth hormone as we age?

1 - GnRH
2 - TSH
3 - androgens
4 - progesterone

A

3 - androgens

38
Q

What affect does obesity have on growth hormone as we age?

A
  • reduces levels of growth hormone
39
Q

Should growth hormone be provides to older patients?

A
  • generally no as there are lots of complications

- malignancy, insulin resistance, oedema, arthralgias, and carpal tunnel syndrome

40
Q

Peak bone mineral density occurs at around 30 years of age. What generally happens to bone mineral density as we age?

A
  • decreases in men and women (women at greater risk)

- increased risk of fragility fracture

41
Q

What causes post-menopausal osteoporosis?

A
  • reduced estrogen
  • estrogen inhibits osteoclasts and cytokines involved in bone reabsorption
  • estrogen levels drop and bone reabsorption increases by up to 90%
42
Q

In addition to low levels of oestrogen, what else can contribute to low BMD as we age?

1 - low vitamin D and Ca2+, hyperparathyroidism, and increased GH
2 - low vitamin D and Ca2+, hypoparathyroidism, CKD and low GH
3 - low vitamin D and Ca2+, hyperparathyroidism, CKD and low GH
4 - increased vitamin D and Ca2+, hyperparathyroidism, CKD and low GH

A

3 - low vitamin D and Ca2+, hyperparathyroidism, CKD and low GH

43
Q

What is the normal pathway for the hypothalamic–pituitary–adrenal axis?

A
  • hypothalamus secretes corticotropin-releasing hormone (CRH)
  • CRH binds with anterior lobe of the pituitary gland causing the release of adrenocorticotropic hormone (ACTH)
  • ACTH binds with adrenal cortex and releases glucocorticoid hormones (mainly cortisol)
  • cortisol provides a negative feedback to ensure cortisol levels do not become too high
44
Q

Then normal pathway for the hypothalamic–pituitary–adrenal axis:

  • hypothalamus secretes corticotropin-releasing hormone (CRH)
  • CRH binds with anterior lobe of the pituitary gland causing the release of adrenocorticotropic hormone (ACTH)
  • ACTH binds with adrenal cortex and releases glucocorticoid hormones (mainly cortisol)
  • cortisol provides a negative feedback to ensure cortisol levels do not become too high

What affect does ageing have on CRH, ACTH and cortisol levels?

A
  • no major affects
  • BUT change in diurnal effects
  • higher cortisol levels released later in the day
45
Q

What is dehydroepiandrosterone (DHEA)?

1 - hormone secreted by pituitary gland
2 - hormone produced by adrenal gland
3 - by product of testosterone
4 - by product of oestrogen

A

2 - hormone produced by adrenal gland

  • DHEA is precursor for other hormones
  • such as testosterone and estrogen
46
Q

Dehydroepiandrosterone (DHEA) is a hormone produced by adrenal gland that is important for producing other hormones. What is the association between levels of DHEA and mortality and functional status in men?

A
  • lower levels of DHEA in ageing = increased mortality and reduced functional status
47
Q

What happens to the incidence of diabetes with ageing?

A
  • increases
48
Q

The incidence of diabetes increases with ageing. What are the 4 most likely mechanisms that have been linked with the increased incidence in ageing?

A
  • decreased insulin secretion from beta cells
  • decreased insulin sensitivity and/or increased insulin resistance
  • increased hepatic glucose output due to low or poor sensitivity to insulin
  • increased obesity (diet and reduced activity levels)
49
Q

Do older patients present in the same way as younger patients with diabetes?

A
  • no
50
Q

Diabetes in older patients does not present the same way as it does in younger patients. What are some reasons why older patients don’t present the same way as younger patients?

A
  • glycaemic threshold in kidney is higher so may not have polyuria (increased urine production)
  • impaired thirst drive so may not have polydipsia (abnormal thirst despite fluid intake)
  • complaints may be more non-specific
  • often will present with a complication like CVA, HHS, or MI
51
Q

Hypoglycaemia is common in patients with diabetes, but why does the risk of hypoglycaemia increase with ageing?

A
  • reduced counter hormones to oral agents or insulin such as glucagon
  • impaired awareness of autonomic symptoms
  • impaired ability to function with low sugar and treat themselves
52
Q

Starvation also referred to as anorexia nervosa is common in ageing. What is starvation?

A
  • severe deficiency in caloric energy intake

- below the level needed to maintain an organism’s life

53
Q

Starvation also referred to as anorexia nervosa is common in ageing, which is severe deficiency in caloric energy intake below the level needed to maintain an organism’s life. What happens to the levels of the following in an elderly patient with starvation:

  • insulin
  • glucose
  • insulin sensitivity
A
  • insulin = reduced production
  • glucose = reduced secretion of glucose
  • insulin sensitivity = increased sensitivity in a an attempt to take up any glucose in blood
54
Q

Leptin is a hormone secreted from fat cells that helps to regulate body weight by doing what?

A
  • inhibiting hunger

- more fat = more leptin in attempt to suppress hunger

55
Q

Reduced levels of leptin have been shown in ageing. What affect would this have on energy intake and energy expenditure?

A
  • low leptin levels = increased food intake
  • low leptin levels = reduced expenditure
  • both would increase the risk of weight gain
56
Q

Reduced levels of leptin have been shown in ageing. What affect does low levels of leptin have on fertility?

A
  • reduced leptin = reduced fertility

- reduces LH and FSH

57
Q

What affect does starvation have on growth hormone?

A
  • increases growth hormone (GH) levels
  • BUT body becomes resistant to GH
  • can be reversible when starvation is stopped
58
Q

What affect does starvation have on the following thyroid hormones:

  • thyroid stimulating hormone (TSH)
  • triiodothyronine (T3)
  • thyroxine (T4)
A
  • TSH and T4 = lower than normal

- conversion of T3 from T4 will be reduced

59
Q

What affect does starvation have on the conversion of thyroxine (T4) to triiodothyronine (T3)?

A
  • reduced T4 conversion to T3 meaning reduced active T3
60
Q

What affect does starvation have on the conversion of thyroxine (T4) to reversed (inactive) triiodothyronine (T3)?

A
  • increased conversion of T4 to reversed T3, which is the inactive form of T3
  • circulating T4 is not needed to make it inactive so it cannot be converted to T3
61
Q

Starvation has the following effect on thyroid hormones:

  • TSH and T4 = lower than normal
  • conversion of T3 from T4 will be reduced

How can this affect the patient?

A
  • reduced basal metabolic rate

- energy conservation (adipose tissue)

Year 2 RE (53 decks)

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