CKD and Renal Failure Flashcards
What are the 4 main functions of the kidney?
Homeostasis
Endocrine
Excretory
Glucose metabolism
What are the endocrine functions of the kidney?
Erythropoietin synthesis
Have 1 alpha hydroxylase for the synthesis of vitamin D
What are the homeostatic functions of the kidney?
Electrolyte balance
Acid-base balance
Volume homeostasis
What are the excretory functions of the kidney?
Nitrogenous waste Hormones Peptides Middle sized molecules Salt Water
What are the functions of the kidney in relation to glucose metabolism?
Carry out some gluconeogenesis
Insulin clearance
What does loss of kidney homeostatic function lead to in terms of potassium, bicarbonate, pH, phosphate, salt and water?
High potassium Low bicarbonate Low pH (patients become acidotic when H+ cannot be removed) High phosphate Salt and water imbalance
What does loss of kidney endocrine function lead to?
Low calcium
Anaemia
High PTH
What does loss of kidney excretory function lead to?
High urea
High creatinine
Low insulin requirement
Why is insulin requirement low in those with kidney failure?
Kidneys get rid of insulin normally. In kidney failure clearance is decreased so less requirement
What is the main systemic risk that increases in kidney failure?
Cardiovascular risk
When assessing a patient with kidney failure what question is it really important to adress?
What their fluid status is- are they hypovolemic, hypervolemic or euvolemic? hypovolemic = low fluid volume
In hypovolemic kidney failure what will happen to levels of urea, creatinine, potassium, sodium, haemoglobin?
High urea High creatinine High potassium Sodium levels vary (depending on hydration) Low haemoglobin
What is important to remember in hyponatremia?
Hyponatraemia does not mean there is low total sodium in the body, it may just mean there is extra fluid
This is why assessing volume status is so important
Why might kidney failure patients not have anemia?
If they present early on eg due to toxin from food causing kidney failure then there may not be effects in the bone marrow
Why might patients with kidney failure not have high potassium levels?
If they have diarrhoea or are vomiting they may be getting rid of the excess potassium
In kidney failure what happens to secretion of salt and water? What are the effects of this?
It falls, this causes hypertension, oedema, pulmonary oedema
What imbalance does acidosis contribute to?
Hyperkalaemia
Why is bicarbonate given to patients with kidney failure?
Mainly to treat hyperkalemia, but also to resolve the acidosis
What is the main issue with having a hyperkalemia?
It leads to cardiac arrhythmia which can eventually be deadly
What is seen on the ECG of someone with chronic kidney disease when they have arrhythmia?
First sign is peaking of T waves P waves: - broaden - reduced amplitude -disappears QRS complex widens Heart block, asystole, VT/VF may occur
Aside from arrhythmia what effects does hyperkalemia have?
Neural and muscular activity is disrupted
Vomiting
Why does anaemia arise in kidney failure?
Reduced erythropoietin
What are CKD patients most likely to die of?
Cardiovascular disease, not end stage renal failure
What does reduced vitamin D cause in patients with kidney disease?
Reduced calcium absorption
Hypocalcaemia
Hyperparathyroidism
How is fluid balance treated in kidney failure?
Hypovolemic give fluids
Hypervolemic- trail of diuretics/dialysis (dialysis if they aren’t peeing)
When deciding how to treat fluid balance in kidney failure what 2 questions do we need to address?
What is their volume status
Are they peeing?
What are the 3 ways to treat hyperkalemia?
Drive into cells via sodium bicarbonate or insulin dextrose (with caution due to risk of hypoglycaemia!! Only done if K+ is >6.6mmol/L)
Drive out of body via diuretics and dialysis
Gut absorption via potassium binders
What is the main method of long term management of CKD?
Transplant if the patient is healthy
What does conservative management for CKD involve?
Erythropoietin injections to correct anemia
Diuretics to correct salt water overload
Phosphate binders (to prevent itching- bind phosphate in stomach so you can excrete it)
1.25 vit d supplements
Symptom management eg anti-nausea
When is conservative management used in CKD?
In old patients, dialysis is an unpleasant process and often conservative treatment will help their symptoms in a much easier way
What are the 2 ways dialysis can be offered?
Home therapy or centre therapy
Why is it important to save veins of CKD patients and how do doctors do this?
They need their veins for dialysis and a fistula to do so (blood from art. to vein to increase size of vein)
To help don’t take blood from their cubital fossa (long term catheter can scar and stenose vein) take it from the back of their hand and don’t insert IV there
Why should you avoid transfusion in CKD patients?
If they are transplantable, transfusion can sensitise them and reduce success of future transplant
How is anaemia ideally treated in CKD patients?
IV iron or erythropoietin
What method is commonly used to asses GFR? Why is ti good
eGFR (estimate of GFR)
Good as it takes into account age and sex but you have to account for ethnicity afterwards
On what basis are CKD patients classified?
GFR
Albumin: creatinine
Why does tachypnea with normal oxygen sats and clear lungs occur?
Respiratory compensation for metabolic acidosis
Trying to get rid off CO2 to increase pH
What equation represents changes in pH?
CO2 + H20 >/< H2CO3 >/< HCO3- + H+
Inc. RR (kasmuraal respiration) = dec. CO2
What are 2 big indicators of renal failure?
High Urea
High creatinine
What is a clinical symptom of hyperphosphatemia?
Itching
What might you see on an ultrasound for renal failure?
Shrunken kidneys
What are complications of renal failure?
Hyperkalaemia
Hyponatraemia
Metabolic acidosis
Anaemia
What are indicators of hypovolaemia?
Low blood pressure
Slow capillary refill time
What might we see in normovolaemic kidney failure?
Inc. urea
Inc. creatinine
Normal K/Na/Hb
What would we see on an ultrasound for acute renal failure?
Normal sized kidneys with no obstruction
What else may be the cause of salt and water loss?
Tubulointerstitial disorders- damage to conc. mechanisms
AKI: leads to hypovolemia
What causes metabolic acidosis?
What can this lead to?
Reduced excretion of H+ ions
Can lead to anorexia and muscle catabolism
What are causes of hyperkalemia?
Dec. distal tubule potassium secretion
Acidosis
What can kidney failure reduce the metabolism off?
Erythropoietin
1-25 vit D levels
What factors contribute to hyperparathyroidism?
Chronic renal failure -> phosphate retention + low 1-25 vit D
-> hypocalcaemia
all lead to: hyperparathyroidism
What are standard cardiovascular risks?
Hypertension
Diabetes
Lipid abnormalities
What are additional cardiovascular risks?
Inflammation
Oxidative stress
Mineral/bone metabolism
What does home therapy for CKD include?
Haemodialysis
Peritoneal dialysis/ assisted programmes
What does in centre therapy for CKD include?
Haemodialysis, 4hrs, 3 times a week
What are methods of assessing GFR? How effective are they?
Urea: poor indicator- confounded by diet, catabolic state, GI bleeding etc.
Creatinine: affected by muscle mass, age, sex etc. Need to look at patient and trent
Radionuclide studies: cr- EDTA clearance, reliable but expensive
Creatinine clearance: Difficult to patients to collect accurate sample. Overestimates GFR at low GFR (small amount of creatine secreted)
Insulin clearance: labrous- used for research only
What are 2 methods used to estimate GFR?
Modification of diet in renal disease (MDRD)
CKD epidemiology collaboration (CKD- EPI) - NICE guidance to use this
