Geriatrics

Question 1

6 renal/bladder changes with ageing

Answer 1

1. Decreased kidney mass mainly due to cortical loss
2. Decreased renal blood flow 10% per decade
3. Reduction in max/min urinary osmolality
4. Reduction in sodium conservation
5. Increased detrusor hyperactivity
6. Increased nocturnal polyuria (due to increased ANP in response to increase in intravascular volume)

Question 2

Age related changes to adrenal hormones

Answer 2

1. Basal renin and aldosterone decreased with constant ratio
2. Stimulus response preserved but its magnitude is decreased

Age related decrease in aldosterone increases the risk of hyperkalaemia

Question 3

Age related changes to the liver

Answer 3

1. Decrease in volume and weight
2. 35% reduction in blood flow which interferes with drug clearance

However no significant changes in LFTs with age
Albumin does not decline in WELL elderly

Question 4

4 Age related changes to the cardiovascular system

Answer 4

1. Decrease in maximum heart rate
2. Resting heart rate and cardiac output largely unchanged
3. Myocardial hypertrophy, increased LV wall thickness and L atrial size occurs with age
4. Increased pulse pressure due to decreased arterial compliance and valve mobility

Question 5

5 Age related changes to the lungs

Answer 5

1. Decreased FEV1 and FVC
2. Increased residual volume due to closure of terminal bronchioles in the dependent parts during tidal breathing
3. Increased V/Q mismatching with rise in physiological dead space
4. Blunted ventilatory response to decreased PaO2 and increasing PaCO2
5. Diminished mucociliary clearance

Question 6

5 endocrine changes in ageing

Answer 6

1. Increased FSH/LH in both sexes
2. Reduced GH
3. Increased ADH with increased risk of hyponatremia
4. Increased PTH with consequent increase in bone resorption
5. Insulin resistance

Question 7

Pharmacokinetic changes and ageing

Answer 7

Absorption is essentially unaltered, but distribution and clearance are significantly affected.

Distribution - reduced liver first pass metabolism, therefore peak drug level will be higher. Also, reduction in lean body mass with increase in fat leads to reduced Vd and increased concentration in water soluble drugs such as digoxin and alcohol, while as fat soluble drugs such as diazepam have greater Vd and prolonged half life.

Clearance is reduced due to age related decline in hepatic and renal function.

Question 8

Define frailty.

What are its phenotypic features?

Answer 8

Distinctive problem of older people due to loss of reserve in multiple body systems with increased vulnerability to stressors and disease. At risk of catastrophic decline in health and function due to relatively mild illness.

Phenotypic features:

1. Unintentional weight loss
2. Reduced muscle strength
3. Reduced gait speed
4. Self reported exhaustion
5. Low energy expenditure

Question 9

Delirium mortality figures at 12 months and 5 years

6 risk factors for delirium from highest to lowest

Answer 9

12 months - 40%
Risk is greatest where delirium not associated with dementia.

5 years - 50%

RF:

1. Cognitive impairment - RR 3-7
2. Use of restraint 4.4
3. Malnutrition 4.0
4. Visual impairment RR 3.5
5. Severe illness RR 3.5
6. IDC RR2.4

Also hearing impairment and psychoactive drug use.

Question 10

MMSE in diagnosis of dementia

Answer 10

Tests broad range of cognitive functions including orientation, recall, attention, calculation, language manipulation and construction praxis. But not effective for testing frontal/executive function

MMSE score <24/30 has poor sensitivity for AD, but good specificity at 96%.

Best used for AD, otherwise a good general screening test

Not good for assessing cognitive decline over time as people memorize the test.

Question 11

Diagnostic features of probable AD

Answer 11

Insidious onset of symptoms with gradual progression.

Features include rapid forgetting and one other cortical manifestation (apraxia, visuospatial, executive, speech dysfunction)

No other physical signs/laboratory evidence of other causes of dementia.

Question 12

Genetic causes of alzheimers dementia

Answer 12

Accounts for only <1%

Mutations in:

1. Amyloid precursor protein - Ch21
2. Presenilin 1 - Ch14
3. Presenilin 2 - Ch1

Presenilin proteins form part of the gamma secretase which cleave APP to give amyloidogenic features.

CSF changes, PET scan changes, MRI changes precede clinical symptoms of AD by 10-15 years in persons at risk of dominantly inherited AD therefore these investigations may be useful (but not in sporadic AD which accounts for most of the patients)

Semegacestat which inhibits gamma secretase inhibitor was disappointing - doesnt work and has lots of side effects.

Question 13

Role of apolipoprotein E in AD

Answer 13

Unclear how this gene causes AD, however E4 allele is a strong risk factor for AD especially with head injury with mean age of onset at 68 vs 84

Even then, 50% of homozygous E4 people are cognitively intact at age of 80

> 50% late sporadic AD have E4 allele.

Question 14

Clinical features of vascular dementia

Answer 14

Early deficits involve attention, executive function and self monitoring.

Memory often is only mildly affected (which distinguishes it from AD)

Often early disturbance of gait which may look like PD but more apraxic features.

Important to note however that just because brain imaging shows ischaemic features, it does not exclude AD.

Question 15

Clinical features of DLB

Answer 15

Rapid onset of progressive decline (faster than AD, 1-4 years vs 5-9 years).

Core features include fluctuating cognition, attention and alertness, recurrent visual hallucinations, spontaneous motor parkinsonism.

Important diagnosis to make as AChEI may be more effective and need to avoid neuroleptic meds need to be avoided.

Question 16

Clinical features of FTD

Answer 16

Impaired personality and social conduct
Disinhibition, apathy, perseveration, stereotypy, hyperorality

Diverse groups including following subtypes:

1. Behavioural subtype
2. Semantic dementia (fluent)
3. Primary progressive aphasia (non-fluent)
4. Motor subtype (MND, PSP, CBD)

50% have family history.
Associated with MND.

Just like VaD, memory often preserved.

Question 17

What is the role of MRI/FDG-PET imaging in dementia?

Answer 17

AD, DLB, FTLD have some characteristic features which distinguishes between them.

AD - generalized atrophy with decreased hippocampal volume, hypometabolism in precuneous and lateral parietotemporal cortex

DLB - generalized atrophy, hypometabolism in occipital cortex

FTLD - regional atrophy and hypometabolism of frontal/temporal areas.

Question 18

Efficacy of cholinesterase inhibitors in dementia

Side effects of cholinesterase inhibitors

Answer 18

In mild-mod dementia, significantly enhanced retention of ADLs and may improve adverse behaviour and delay its onset.

Theoretically DLB more likely to benefit but good quality data lacking

No evidence in VaD, MCI (increased vascular death), FTD. Modest benefit of rivastigmine in PDD.

Increased GIT motility (diarrhoea, nausea, anorexia)
Vagotonic bradycardia
Exacerbation of asthma
Sleep disturbances and vivid dreams

Question 19

MoA and efficacy of memantine

Answer 19

Neuroprotective NMDA antagonist which blocks glutamate induced neurotoxicity.

Studied in mod-severe AD/VaD, and as an add-on therapy in mild-mod AD.

Well tolerated (may cause seizures)

Used for MMSE 10-14 and as a monotherapy.

Question 20

Risk factors for falls

Answer 20

Age
History of falls
ADL limitations

Impaired gait/mobility
Impaired sit-stand and transfers

Impaired visual contrast sensitivity
Impaired peripheral sensation

Impaired cognition
Stroke
Parkinsons disease

Psychoactive medication use
>4 meds

Question 21

Management of stress/urge incontinence

Answer 21

General measures include:

1. Pelvic muscle exercise - first line for stress incontinence
2. Bladder retraining - gradually extend period between voids to increase bladder capacity
3. Timing of oral fluids, reduce caffeine
4. Treat constipation
5. Weight loss

Urge incontinence - trial antimuscarinic such as oxybutynin, solifenacin if cognitively intact

Stress-incontinence in females - topical estrogen to help with urethral atrophy.

Mid-urethral sling surgery is effective as first line in stress incontinence, but NEED TO exclude URGE INCONTINENCE with urodynamic surgery before proceeding with surgery as it can be made worse.

Question 22

Pathogenesis of delirium - key neurotransmitters involved

Answer 22

Acetylcholine - reduced. Hence this is the reason why people with alzheimers disease and anticholinergic agent usage can increase susceptibility to delirium

Dopamine - increased

Question 23

Management of psychosis in Parkinsons disease

Answer 23

1. Treat the underlying cause and cease contributing medications
2. If these conservative managements do not resolve delirium, then stop parkinsons medications from least potent to most potent:
   - Anticholinergics - eg benztropine
   - Amantadine
   - MAOB inhibitors (selegiline)
   - COMT inhibitors - entacapone
   - Dopamine agonist - pramipexole, cabergoline, apomorphine
   - Levodopa

Question 24

Association of BP and walking speed

Answer 24

Higher systolic BP was associated with increased risk of mortality only among elderly adults with medium to fast walking pace. In slower walking older adults, there was no association between elevated systolic or diastolic BP and mortality.

In slow walkers, elevated systolic and diastolic BP was actually independently associated with LOWER mortality risk.

Low diastolic pressure may contribute to high PP which is a strong risk factor for coronary events in elderly.

Question 25

Diagnostic criteria for bvFTD

Answer 25

Possible bvFTD requires 3/6:

Disinhibition
Apathy
Loss of sympathy/empathy
Perseverative/compulsive behaviour
Hyperorality
Dysexecutive neuropsychological profile

Probable bvFTD requires 3/6 as well as imaging findings that reflect FTD (such as frontotemporal atrophy, hypometabolism or hypoperfusion on PET)