The ageing GI tract and skin Flashcards
What are the functions of the skin?
- Protection
- Regulation
- Perception
- Vit D synthesis
In ageing skin, what happens to the dermo-epidermal junction and what impact does it have?
- Dermoepidermal junction flattens
- Decreases nutrient transfer
What happens to the sweat glands?
Decrease in number and production of sweat glands
In the epidermis, what happens to the Langerhans’ cells?
Decrease in the immunologically active Langehans’ cells
Why do elderly patients get dry skin (xerosis)? How is it treated?
- Flattened dermoepidermal junction prevents lipid transfer to stratum corneum
- Less sweat glands
- Treated with emollients
Why does ageing skin get wrinkly and saggy?
- Decrease in subdermal fat skin
- Elastin biosynthesis declines significantly after fourth decade
- Thinning of epidermis
- Dermoepidermal junction flatter -> fragile skin
Why do older people have increased susceptibility to trauma?
- Dermoepidermal junction is weak
- Increased fragility of the skin to shear stress
- Bleeding into space between dermis + epidermis occurs more frequently
Why is there delayed wound healing?
- 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
How are pressure ulcers graded?
- Grade 1 - redness, intact, oedema, warm
- Grade 2 - abrasion/blister, skin loss, at epi/dermis
- Grade 3 - necrosis in subcutis
- Grade 4 - necrose right through fascia
Why is there impaired thermoregulation in ageing skin?
- 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
What are the reasons for impaired sensory perception?
- 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
How does vitamin D synthesis decrease in an older person?
- 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
What happens if you’re vitamin D deficient over a prolongued period?
The following occur one after another:
- Decreased intestinal absorption of calcium + phosphorus
- Hypocalcaemia occurs
- Seondary hyperparathyroidism
- Phospaturia
- Deminieralisation of bones
- Osteopenia + osteomalacia
What features are present in a patient with osteomalacia?
- Fractures can occur
- Proximal muscle weakness
- Bone pain
What is the Age UK reccommendation for getting sun per day?
10-15 mins a day without sunscreen
Describe changes that are induced in the skin by photoageing
- 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
What happens to nails with ageing?
50% overall reduction in nail growth so any damage occurring takes longer to heal
Also, in some patients nails thicken + harden (onychogryphosis)
What is achromotrichia?
- Grey hair
- Decrease in melanocytes - in epidermis + hair
- Order: nose, head, beard, body, eyebrows
What are Campbell de Morgan spots?
- Completely harmless
- Common in elderly patients
What are functions of the GI tract?
- Digestion
- Absorbing nutrients + water
- Electrolyte balance
- Immune barrier
- Expelling waste
What happens to the oropharynx in ageing?
- 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
Why is swallowing harder in the elderly and what does this increase the risk for?
- 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
What happens to the oesophagus itself with ageing?
- 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)
What happens to the stomach with ageing and what does this increase the risk for?
- 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
What happens to the small intestine with ageing?
- 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
What happens to the large intestine with ageing and what does this lead to?
- 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
Which condition is common among the elderly population, affecting the large intestine?
Diverticular disease
What changes occur in the hepatobiliary system?
- 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
Why are lower doses of vitamin K antagonists needed to anticoagulate older people?
Vitamin K responsible in clotting/coagulation, there is decreased synthesis of Vitamin-K-dependent clotting factors. Therefore lower doses of Vit K antagonists needed.
What happens to the pancreas with ageing?
- Exocrine pancreas undergoes only modest alterations with age
- Minor atrophic and fibrotic changes have essentially no impact on pancreatic exocrine function
Why is it that a patient can present with diarrhoea despite being constipated?
They will pass lots of liquid stool as the liquid actually goes around the impacted hard stool, which is stuck in the rectum
