CKD and kidney decline in the elderly

Question 1

what is the definition of CKD ?

Answer 1

abnormalities of kidney function or structure for more than three months with implications for health

Question 2

how is absorption affected by age ?

Answer 2

the rate of absorption decreases. Gastric emptying is slower blood flow is slower.
The pH rises due to reduced number of parietal cells

Question 3

how is distribution affected by age ?

Answer 3

Weight is lost as old people become frail therefore the volume of distribution decreases due to less SA .

Question 4

how is metabolism affected by age ?

Answer 4

metabolic clearance decreases with age.

Question 5

how is elimination affected by age?

Answer 5

renal clearance decreases because the rate of filtration decreases.
which means the half life of a drug increases so it takes the drug longer to reach steady state (Css)

Question 6

how is distribution affected by CKD ?

Answer 6

volume of distribution increases due to oedema and reduced protein binding which means more free drug available

Question 7

how is metabolism affected in CKD?

Answer 7

Overall get a decrease in metabolism due to the decreased activity of CYP enzyme.
But can get a short increase due to increased amount of free drug

Question 8

what are some of the risks with administering drugs to a patient with CKD?

Answer 8

Toxicity and side effects due to build up renal excreted drugs.
Risk of infectiveness some drugs need a certain egfr to work
risk of exacerbating CKD and worsening renal function

Question 9

what are the causes of CKD?

Answer 9

genetic malformations
hypertension (kidneys overworking)
glomelularnephritis - inflammation
diabetes
recurrent UTIs
Lupus and other immune conditions 
Polysystic kidney disease
obstructions

Question 10

How do you treat impaired homeostatic kidney function?

Answer 10

• fluid restriction for oedema
• diuretics - only in CKD not AKI to offload excess fluid
• sodium bicarbonate to maintain oxygen potassium levels
• use ace inhibitors as they are nephroprotective

Question 11

what is hyperkalemia and why how is it treated?

Answer 11

it is a high concentrations of K+ which can cause caridac arrhythmias
so aim to stabilise cardiac cells and reduce serum potassium

Question 12

how do you stabilise cardiac cells in CKD?

Answer 12

10ml calcium gluconate IV slow bolus and repeat until ecg stabilises

Question 13

how do you reduce serum potassium levels in CKD?

Answer 13

50ml of 50% glucose with 10 units of act rapid insulin over 10 mins - given at the same time to cancel each other

also consider 10-20mg of nebuliser salbutamol

Question 14

why dose renal bone disease happen?

Answer 14

happens due to the disruption of parathyroid hormone, potassium,vitamin d and calcium

Question 15

How is phosphate affected in CKD?

Answer 15

phosphate is normally excreted by renal tubules. so phosphate levels rise in the blood as it cannot be excreted

Question 16

what does vitamin d do for the body?

Answer 16

its essential for good bone health by promoting GI absorption of calcium and renal tubular reabsorption of calcium aiding mineralisation of the bone

Question 17

How is vitamin d affected in CKD?

Answer 17

vitamin d is activated in the kidney therefore there is reduced activation of vitamin d

Question 18

Why can’t colecealciferol be taken by a patient with CKD?

Answer 18

It needs to be activated in the liver and the kidney by 2 hydroxylation reactions to get the active form so you cannot use it in renal impairment.

Question 19

How is vitamin d affected in CKD?

Answer 19

high phosphate levels in the blood means that phosphate binds to circulation calcium un the blood .
Vitamin D is not activated so there is less calcium reabsorption
Overall calcium levels decrease.

Question 20

what is parathyroid hormone?

Answer 20

it is responsible for the homeostasis of calcium in the blood

Question 21

How is parathyroid hormone affected in CKD?

Answer 21

low levels of Ca2+ and activated vitamin D in the blood causes the release of PTH
PTH increases bone turnover to get calcium out of the bones and rises calcium levels in the blood causing brittle bones

Question 22

How does PTH maintain calcium homeostasis ?

Answer 22

• it increases urinary excretion of phosphate so it binds less to ca2+ increasing serum calcium levels
• it decreases calcium excretion in the urine increasing calcium serum concentrations
• increases vitamin d synthesis and activation
• increases bone turnover and release calcium stores from the bone
• when ca2+ and vitamin D levels increase they act as negative feedback to reduce PTH secretion

Question 23

what is secondary hyperthyroidism ?

Answer 23

when the vitamin D receptors become reduced and there is reduced sensitivity to serum calcium levels so PTH continue to be secreted .
Now calcium levels are above normal range and it becomes tertiary hyperthyroidism

Question 24

what is tertiary hyperthyroidism ?

Answer 24

the parathyroid is actin autonomously and drug treatment becomes difficult

Question 25

what is a first line treatment for CKD ?

Answer 25

Managing the high phosphate levels by dietary restriction of phosphate rich foods
e.g. beans dairy or ham

Question 26

what is a second line treatment for CKD ?

Answer 26

phosphate binder medications

can use calcium based and non calcium based

Question 27

why does non calcium based phosphate binders not work in secondary hyperthyroidism?

Answer 27

As the patient already has high calcium levels and giving the patient more calcium will only increase the serum calcium level

Question 28

why is vitamin D alfacalcidol prescribed?

Answer 28

suppresses PTH release when Ca2+ levels are low and PTH is still high an its not controlled by phosphate binders

Question 29

what are calcimemetics ?

Answer 29

they mimic the action of Ca2+ on the receptors of the parathyroid gland decreasing PTH secretion.
Have very strict prescribing guidelines as they are expensive
commonly used in patients not fit for surgery and can be used in combination with phosphate indoors and vitamin D.

Question 30

what should be monitored during CKD treatment?

Answer 30

PTH , calcium and vitamin D levels

Question 31

what is erythropoietin ?

Answer 31

a growth factor that promotes red blood cell formation and releases reticulocytes from the bone marrow

Question 32

What Is the treatment for anaemia ?

Answer 32

ESA’s which go into the bone marrow and stimulates the abc growth by mimicking the endogenous erythropoietin .
either subcutaneous injection , IV or via dialysis machine

Question 33

what is restless legs

Answer 33

due to the build up of toxic waste products such as urea

Question 34

what is the treatment for restless legs

Answer 34

using a pedal bike or clonazepam , ropinrol or gabapentin