The Ageing Endocrine Systems Flashcards
What is meant by ‘compression of morbidity’?
Popular with geriatricians - aim is that illness and disability squeezed into a short period at the end of life
What is the endocrine system?
Made up of organs + tissues that produce hormones
What is a hormone?
- A chemical messenger
- Released into the bloodstream from one location to target other organs or tissues
- Amino acid or steroid based
How does the hypothalamus link the nervous system to the endocrine system?
Via the pituitary gland
Where is the central circadian clock located in the hypothalamus?
Suprachiasmatic nucleus
What changes occur as a result of the ageing hypothalamus?
- Circadian rhythm diminishes with age
- Decreased sleep + disturbed sleep/wake cycle
- Diminished appetite
- Poor thermoregulation
Is it the posterior or anterior pituitary that produces its own hormones?
Anterior pituitary produces its own hormones. Posterior pituitary stores hormones made in the hypothalamus.
mnemonic: GOAT FLAP
Which hormones does the pituitary gland produce? Which of these two are produced by the posterior pituitary?
- Growth hormone (GH)
- Oxytocin
- Anti-diuretic hormone (ADH)
- Thyroid stimulating hormone (TSH)
- Follicle stimulating hormone (FSH)
- Luteinising hormone (LH)
- Adrenocorticotropic hormone (ACTH)
- Prolactin
What is growth hormone also known as?
Somatotropin
What is the action of growth hormone?
- Causes production of IGF-1 from liver
- Involved in protein, fat + carbohydrate metabolism (gluconeogenesis, muscle growth, bone growth)
What happens to growth hormone levels with age?
- Growth hormone decreases with age
- GH secretion from pituitary declines progressively after puberty -> decreased levels of IGF-1
- Decreased muscle mass + bone density
- Somatopause
What are advantages of replacing growth hormone?
- Increased lean body mass
- Decreased adipose tissue
- Increased bone density
What are limitations of replacing growth hormones?
- Has to be given subcutaenously
- Difficult dosing
- Side effects - hyperglycaemia, oedema, arthralgia
- Increased IGF-1 can increase malignancy
- Cost
Which is the active hormone released from the thyroid?
T3 - causes most of the metabolic effects
(T4 is a peripheral storage of thyroxin and just gets converted to T3)
What changes occur regards to the thyroid gland with age?
- TSH increases
- T4 levels remain unchanged
- Increased levels of thyroid antibodies (autoimmune)
- Both hyperthyroidism and hypothyroidism more prevalent - many undiagnosed
What is sick euthyroid syndrome and what is it caused by?
- Abnormal TFTs in patients unwell with non-thyroid systemic disease
- Caused by:
- > reduced TSH secretion
- > lower thyroid hormone binding
- > reduced peripheral T4 -> T3 (so T4 remains normal)
- These^ reverse once underlying illness improves
What are clinical features of hypothyroidism?
- Hearing loss
- Psychosis, depression, coma
- Loss of outer eyebrows + dry, brittle hair
- Thick, coarse features
- Goitre, hoarse voice
- Congestive cardiac failure, bradycardia, hypertension
- Slow reflexes, myalgia, carpel tunnel
- Ataxia, anorexia, overweight, constipation, menorrhagia
- Cold intolerance
- Oedema
What are clinical features of hyperthyroidism?
- Restlessness, malaise, irritability, psychosis
- Goitre, bruit
- Opthalmoplegia, exopthalmos
- Periorbital oedema
- Heat intolerance
- Tachycardia, AF, hypertension, CCF, SoB
- Tremor, palor, erythema, onycholysis
- Thirst, weight loss, poor appetite, d&v
- Proximal myopathy, pretibial myxoedma
What is the visible difference between exophthalmos and proptosis?
- Exophthalmos = eye protruding from orbit (can see white above AND below pupil)
- Proptosis = eye bulging out, can cause chemosis
Why is thyroid disease tricky to detect in the elderly?
- Symptoms are non-specific and often mistaken for the ‘normal ageing’ process
- Examination is difficult as thyroid may be shrunken + kyphotic posture
- Overlapping presentation of hypo- + hyper-thyroidism in elderly (confusion, depression, incontinence etc)
What does the adrenal cortex produce?
- Aldosterone
- Cortisol
What does the adrenal medulla produce?
Catecholamines (adrenaline + noradrenaline)
What happens to adrenal function with age (specifically cortisol)?
- Cortisol is the stress hormone
- Levels increase with age
- Diurnal variation in cortisol is altered in elderly
- Chornically elevated levels have been implicated with numerous age-related conditions eg. cog impairment, CVD
What is menopause and when does it occur?
- Cessation of menstruation due to ovarian failure
- 45-55
What hormone changes occur post-menopause?
- Oestrogen levels fall
- FSH and LH increase initially + then fall
What are the immediate post-menopausal symptoms?
- Hot flushes
- Insomnia
- Altered mood
- Atrophy of oestrogen responsive tissue
What are the long term symptoms/impacts of menopause?
- Increased cardiovascular risk
- Rapid loss of skeletal mass + bone mass
- Vasomotor instability
- Psychological symptoms
- Loss of libido
When should hormone replacement therapy be used?
- menopausal symptoms where the risk:benefit ratio is favourable
- For women with early menopause
What are the benefits of HRT?
- Improve vasomotor symptoms
- Reduction in osteoporosis
- Improve sleep + mood
- Reduce risk of colorectal cancer
- Reduce risk of cardiovascular disease
What are risks of HRT?
- Small inc risk of breast, ovarian + endometrial cancer
- Increased risk of venous thromboembolism
- Increased risk of stroke
- Increased risk of cholecystitis
- Side effects eg. bloating, breakthrough bleeding, breast tenderness
What are non-HRT options?
- Atrophic vaginitis - use topical oestrogens
- Clonidine (a-stimulant) may reduce hot flushes (though can inc BP)
What happens to gonadal function in ageing men?
- Testosterone levels decrease w age
- Decreased libido
- Reduced muscle strength + bone mineral density
Should we replace testosterone in the elderly?
- Consider for patients w symptoms of hypogonadism and/or markedly reduced levels of testosterone
- Can improve bone mineral density, muscle mass, libido, mood etc
- BUT REMEMBER, contraindicated in prostate cancer, increased risk of heart disease
What changes occur with glucose metabolism in ageing?
- Beta cell function declines
- Glucose-induced insulin release is delayed + smaller
- Peripheral insulin resistance increases
- —-> increased impaired glucose tolerance + progression to T2DM
What are secondary causes of diabetes mellitus?
- Steroids
- Thiazides
- Pancreatitis
- Cushings disease
- Hyperthyroidism
Diabetes mellitus is difficult to diagnose in the elderly due to symptoms sometimes being related to ‘ageing’, what are these symptoms?
- Glucosuria + polyuria occur later
- Impaired thirst (polydipsia occurs later)
- Presentation: coma, delirium, thrush, cellulitis, weight loss, urinary incontinence, general malaise, vascular disease, peripheral neuropathy
What are microvascular complications of diabetes?
- Diabetic retinopathy
- Diabetic nephropathy
- Diabetic neuropathy
What are macrovascular complications of diabetes?
- Stroke
- Heart disease
- Peripheral vascular disease
What are limitations to treating diabetes in the elderly?
- Risk of drug-induced hypoglycaemia, confusion falls + fractures
- LT benefits of treatment unknown in frail or >80
- Practical difficulties with administering insulin
- Full compliance with dietary change or insulin not always possible
- Dietary change could cause loss of QoL
What changes occur in regards to parathyroid gland function and associated hormones, with age?
- PTH rises with age
- Reduced sunlight exposure
- Post menopausal reduced hydroxylation of Vit D
- Reduced effect of PTH (altho counterbalanced by PTH rise)
- Diminished capacity of skin to convert cholesterol to Vit D
Ageing leads to a decrease in overall bone mineral density, leading to which disease?
Osteoporosis
Summary Q: Which 2 hormones increase with age?
- Cortisol
- PTH
- (TSH gradually does)
The rest decrease and T4 remains unchanged
What are easy, cheap yet important tests used to screen in the elderly?
- TFTs
- Vit D
- Ca
- Haematinics (iron, b12, folate)
