Pathophysiology of Aging

Question 1

There are 3 different “Theories” of aging:

• Stochastic
• Programmed
• Homeostasis failure

How do the first 2 work?

Answer 1

Stochastic - Cumulative random damage

Programmed - Predetermines changes in gene expression

Question 2

What are the types of changes in aging?

Answer 2

• Beneficial e.g. experiential learning
• Neutral e.g. grey hair
• Detrimental e.g. hypertension or decreased balance

Question 3

Frailty is effectively progressive dyshomeostasis. Explain this using cold stress as an example?

Answer 3

Cold stress on a young person:
- They will peripherally vasoconstrict & increase metabolic heat production –> Coping well with the cold

Cold stress in a frail person:
- Reduced coping mechanisms –> Hypothermia

Question 4

Define “social” dyshomeostasis?

Answer 4

Loss of ability to compensate for environmental changes not biomechanical
e.g. when the spouse dies or a daughter goes on holiday

Question 5

Remember that any medical condition that effects healthy people can also affect the frail

Answer 5

And that they can present very differently e.g. hyperthyroidism

Question 6

What are the practical implications of the aging population for us as future doctors?

Answer 6

• More people with co-mobordities
• Greater inter-individual variability in function/reserve
• Mixed up diseases presenting very similarly
• Little evidence e.g. drug trials in >80s (because its hard)
• Polypharmacy –> More ADRs & Drug interactions

Question 7

How does hyperthyroidism present in normal and then in the elderly?

Answer 7

Normal presentation:

• tremor
• weight loss
• diarrhoea
• anxiety

Person with frailty

• depression
• cognitive impairment
• muscle weakness
• atrial fibrillation
• heart failture
• angina

Question 8

what are the difference in the young and the elderly when it comes to normothermia

Answer 8

In the elderly minor changes in temperature have an impact on circadian rhythm

Question 9

what are the differences in young and elderly when it comes to Heat stress

Answer 9

• reduced sweat gland output
• reduced skin blood flow
• smaller increase in cardiac output
  less redistribution of blood flow from renal and splanchnic circulations

Question 10

Define frailty

Answer 10

A susceptibility state that leads to a person being more likely to lose function in the face of a given environmental challenge

Question 11

What are the main frailty syndromes

Answer 11

• Falls
• Delirium
• Immobility
• Incontinence