The ageing GI tract and skin

Question 1

What are the functions of the skin?

Answer 1

• Protection
• Regulation
• Perception
• Vit D synthesis

Question 2

In ageing skin, what happens to the dermo-epidermal junction and what impact does it have?

Answer 2

• Dermoepidermal junction flattens
• Decreases nutrient transfer

Question 3

What happens to the sweat glands?

Answer 3

Decrease in number and production of sweat glands

Question 4

In the epidermis, what happens to the Langerhans’ cells?

Answer 4

Decrease in the immunologically active Langehans’ cells

Question 5

Why do elderly patients get dry skin (xerosis)? How is it treated?

Answer 5

• Flattened dermoepidermal junction prevents lipid transfer to stratum corneum
• Less sweat glands
• Treated with emollients

Question 6

Why does ageing skin get wrinkly and saggy?

Answer 6

• Decrease in subdermal fat skin
• Elastin biosynthesis declines significantly after fourth decade
• Thinning of epidermis
• Dermoepidermal junction flatter -> fragile skin

Question 7

Why do older people have increased susceptibility to trauma?

Answer 7

• Dermoepidermal junction is weak
• Increased fragility of the skin to shear stress
• Bleeding into space between dermis + epidermis occurs more frequently

Question 8

Why is there delayed wound healing?

Answer 8

• Dermis thins with decreased vascularity and biosynthetic capacity of fibroblasts
• Epidermal turnover is slowed due to decreased divison of keratinocytes and longer migration from the basal layer to skin surface
• Prone to developing pressure ulcers

Question 9

How are pressure ulcers graded?

Answer 9

1. Grade 1 - redness, intact, oedema, warm
2. Grade 2 - abrasion/blister, skin loss, at epi/dermis
3. Grade 3 - necrosis in subcutis
4. Grade 4 - necrose right through fascia

Question 10

Why is there impaired thermoregulation in ageing skin?

Answer 10

• Ability to deliver heat to the epidermis for excretion is impaired - loss of dermal capillaries
• Loss of subdermal fat decreases insulation
• Decrease in number + production of sweat glands

Question 11

What are the reasons for impaired sensory perception?

Answer 11

• Sensory perception of the skin decreases, esp in lower extremities
• Decreased Meissner’s corpuscles -> reduced light touch sensation
• Decreased Pacinian corpuscles -> reduced low frequency vibration

Question 12

How does vitamin D synthesis decrease in an older person?

Answer 12

• Ultraviolet rays convert 7-dehydrocholesterol to pre-vitamin D3 in the epidermis
• Levels of 7-dehydrocholesterol decrease with age, therefore decreasing the older person’s capacity for vit D synthesis

Question 13

What happens if you’re vitamin D deficient over a prolongued period?

Answer 13

The following occur one after another:

• Decreased intestinal absorption of calcium + phosphorus
• Hypocalcaemia occurs
• Seondary hyperparathyroidism
• Phospaturia
• Deminieralisation of bones
• Osteopenia + osteomalacia

Question 14

What features are present in a patient with osteomalacia?

Answer 14

• Fractures can occur
• Proximal muscle weakness
• Bone pain

Question 15

What is the Age UK reccommendation for getting sun per day?

Answer 15

10-15 mins a day without sunscreen

Question 16

Describe changes that are induced in the skin by photoageing

Answer 16

• Cellular dysplagia
• Atypical cells
• Loss of polarity of the keratinocytes
• Disorganisation in epidermis
• Elastosis in dermis
• Decrease in collagen content
• Inflammatory infiltrate localised to the perivascular areas

-> wrinkled, lax, yellowed, rough skin, telangiectasias, patchy hyper- and hypopigmentation

Question 17

What happens to nails with ageing?

Answer 17

50% overall reduction in nail growth so any damage occurring takes longer to heal

Also, in some patients nails thicken + harden (onychogryphosis)

Question 18

What is achromotrichia?

Answer 18

• Grey hair
• Decrease in melanocytes - in epidermis + hair
• Order: nose, head, beard, body, eyebrows

Question 19

What are Campbell de Morgan spots?

Answer 19

• Completely harmless
• Common in elderly patients

Question 20

What are functions of the GI tract?

Answer 20

• Digestion
• Absorbing nutrients + water
• Electrolyte balance
• Immune barrier
• Expelling waste

Question 21

What happens to the oropharynx in ageing?

Answer 21

• Epithelial lining of oral mucosa thins
• Gums recede, exposing tooth cementum -> prone to decay, root caries + incomplete mastication
• Salivary glands - decrease in # of acinar cells + up to 50% decrease in saliva production from parotid salivary glands
• Subjective complaints of dry mouth (xerostomia) -> impact chewing/swallowing (often from medication than ageing)
• Reduced taste perception

This increases the risk of malnutrition

Question 22

Why is swallowing harder in the elderly and what does this increase the risk for?

Answer 22

• Loss of oesophageal muscle compliance - increased resistance to flow across upper oesophageal sphincter
• Less effective mastication + decreased food clearance from pharynx

This increases the risk for aspiration pneumonia

Question 23

What happens to the oesophagus itself with ageing?

Answer 23

• Hypertrophy of skeletal muscle at the upper third
• Decrease in myenteric ganglion cells that coordinate peristalsis
• Reduced secondary oesophageal contractions
• Impaired sensation of distention

-> this leads to increased gastric acid exposure (also due to loss of sphincter function)

Question 24

What happens to the stomach with ageing and what does this increase the risk for?

Answer 24

• Prevalence of H. Pylori increases with advancing age
• Decreased prostaglandin synthesis
• Decreased hydrocholric acid secretion
• Decreased pepsin secretion
• Delayed gastric emptying

This increases risk of infection and ulceration with decreased digestion

Question 25

What happens to the small intestine with ageing?

Answer 25

• Moderate villous atrophy + coarsening of mucosa
• Decreased efficiency of calcium absorption from the gut lumen - decreased vitamin D receptors in the gut + decreased levels of circulating 25(OH) vit D
• Decreases in sensory + myenteric neurons

This leads to increased frequency of painless ulcers with increased age

Question 26

What happens to the large intestine with ageing and what does this lead to?

Answer 26

• Mucosal atrophy
• Decreased muscle wall strength
• Decreased bowel wall compliance
• Increased intra-abdominal pressure required for stool excretion
• Slower larger bowel transit + inc segmental contractions (as opposed to propulsive contractions) -> inc water reabsorption, harder stools

This can lead to constipation

Question 27

Which condition is common among the elderly population, affecting the large intestine?

Answer 27

Diverticular disease

Question 28

What changes occur in the hepatobiliary system?

Answer 28

• Liver mass decreases
• Perfusion + blood flow decreases up to 50% between the 3rd and 10th decades of life
• “Liver function tests” (transaminases, alkaline phosphatase) minimally affected by age
• Metabolism of LDL cholesterol decreases
• Cytochrome P450 function decreases with age
• Regenerative response to liver injury reduced - reduced mitogen-activated protein kinase activity

This all leads to reduced metabolic clearance of some drugs

Question 29

Why are lower doses of vitamin K antagonists needed to anticoagulate older people?

Answer 29

Vitamin K responsible in clotting/coagulation, there is decreased synthesis of Vitamin-K-dependent clotting factors. Therefore lower doses of Vit K antagonists needed.

Question 30

What happens to the pancreas with ageing?

Answer 30

• Exocrine pancreas undergoes only modest alterations with age
• Minor atrophic and fibrotic changes have essentially no impact on pancreatic exocrine function

Question 31

Why is it that a patient can present with diarrhoea despite being constipated?

Answer 31

They will pass lots of liquid stool as the liquid actually goes around the impacted hard stool, which is stuck in the rectum