1b Chronic Kidney Disease and Renal Failure Flashcards
What are the important aspects of homeostatic function of the kidney?
Electrolyte balance
Acid base balance
Volume homeostasis
What are the important aspects of excretory function of the kidneys?
nitrogenous waste
hormones
peptides
middle sized molecules
salt and water
What is the endocrine function of the kidneys?
EPO production and 1-alpha hydroxylase vitamin D
What are the important aspects of glucose metabolism in the kidneys?
Gluconeogenesis and insulin clearance
What type of anaemia does loss of EPO production result in?
Normocytic and normochromic
What happens to potassium levels in a patient with kidney failure?
increase
What happens to bicarbonate levels in a patient with CKD?
decrease
What happens to phosphate levels in a patient with CKD?
increase
What happens to the pH of the blood in a patient with CKD?
lowers
What does a reduction in 1 alpha hydroxylase vitamin D lead to?
reduced calcium and increased parathyroid hormone
What happens to urea and creatinine in a CKD patient?
Both increased
What is the key condition which patients with CKD will die from due to an increased risk?
Cardiovascular risk
What are some clinical signs of CKD?
- high creatinine
- feeling weak, too weak to move
- pale
- hand cold and decreased capillary refill
- hypotensive
- tachypnoeic despite 100% O2 sats and clear lungs
What is the volume assessment of a CKD patient?
volume depleted, hypovolemic = dry volume status
What type of breathing might CKD patients present with?
Kussmaul respiration
Why does the respiratory rate increase for patients with CKD despite clear lungs and 100% O2 sats?
excess hydrogen ions which is converted into carbon dioxide - this stimulates breathing to remove the excess H+ = results in KUSSMAUL breathin
What is Kussmaul respiration a key sign of?
Acidosis
What is the common acid base status of a patient with CKD?
metabolic acidosis with respiratory compensation
Why does respiratory compensation occur in CKD?
Low pH = acidosis, bicarbonate low so metabolic acidosis, Carbon dioxide also low so has been some respiratory compensation = breathing out carbon dioxide to try and reduce CO2
What happens to the size of the kidneys in CKD?
Shrinking of the kidneys - on an ultrasound
What happens to the kidney size on AKI?
Preserved
What symptoms might someone experience with CKD?
Symptoms of extreme lethargy, weakness and anorexia.
Clinically volume depleted resulting in severe hypotension.
Elevated plasma urea and creatinine make diagnosis of renal failure.
What is the acid base status in AKI?
Mild metabolic acidosis with respiratory compensation
Kidney failure tends to REDUCE secretion of salt and water leading to:
Hypertension
Oedema
Pulmonary oedema
Due to water and salt retention
In which situation might salt and water loss be seen?
tubulointerstitial disorders due to the concentrating mechanism
results in hypovolemia = due to loss of fluid through vomiting
What is meant by oedema?
Oedema = excess extracellular fluid
What is the main extracellular ion?
sodium
Describe the acidosis mechanism in kidney failure?
reduce excretion of H+ ions, results in increased H+ ions in the blood
The body wants to get rid of these so:
They enter into the cells and as a result the H+ ions swap for potassium, which leave the cells
This results in a rise of potassium in the blood = hyperkalaemia
What symptoms does acidosis due to kidney failure result in?
Anorexia
Muscle Catabolism
What are the causes of hyperkalaemia due to kidney failure?
↓ Distal tubule potassium secretion
Acidosis
What are the symptoms which result from hyperkalaemia due to kidney failure?
Cardiac arrhythmias
Neural and muscular activity
Vomiting
What are the ECG changes which are seen due to hyperkalaemia?
Peaked T waves
P wave - broadens
- reduced amplitude -
- disappears
QRS widening
Heart block
Asystole
VT/VF
What does reduced EPO as a result of kidney failure lead to?
Anaemia
What does reduced vitamin D as a result of kidney failure lead to?
Reduced intestinal calcium absorption
Hypocalaemia
Hyperparathyroidism
Why does CKD lead to phosphate retention?
Kidneys not working-> GFR drops -> less phosphate excreted
What impact does phosphate retention have?
Calcium levels go down (also as a result of low levels of vitamin D), which leads to hyperparathyroidism
Describe the effect of vitamin D on PTH?
Vitamin D suppresses PTH production so low vit D will increase PTH production
Which type of hyperparathyroidism occurs?
Secondary, which can eventually change into tertiary
What is the major outcome for a patient with CKD?
Cardiovascular disease
What are the three components of a standard cardiovascular risk?
Hypertension
Diabetes
Lipid Problems
What are the additional CVD risks due to CKD?
Inflammation
Oxidative stress
Mineral / Bone metabolism disorders
What medication is used to drive K+ back into cells?
Sodium bicarbonate
How is the fluid balance restored?
If hypo = give IV fluids
If Hyper = use dialysis
What are the treatments for hyperkalaemia
Sodium bicarbonate to drive K+ into the cells
Diuretics to drive K+ into the cells
gut absorption - use potassium binders to bind the excess potassium in the gut
what are the conservative treatment methods for long term management?
- erythropoietin injections to correct anaemia
- diuretics to correct salt-water overload
- phosphate binders to reduce phosphate to prevent bone disease
- 1.25 vit d supplements
- symptom management
What is the best treatment for CKD?
Kidney transplant
What is the equation used to work out the chance of the patient reaching end stage renal failure in the next five years?
Kidney Failure Risk Equation
Which patients is the KFRE not used in?
patients with a rapidly changing eGFR
Why should transfusions be avoided?
transfusion -> sensitisation -> transplant failure
Why is UREA a poor method of measuring GFR?
Confounded by diet, catabolic state, GI bleeding (bacterial breakdown of blood in gut), drugs, liver function etc.
what are the problems associated with using creatinine clearance?
Overestimates GFR at low GFR (as a small amount of creatinine is also secreted into urine)
Difficult for elderly patients to collect an accurate sample
why is creatinine not effective of assess GFR?
Affected by muscle mass, age, race, sex etc.
Need to look at the patient when interpreting the result. TREND helpful.
What happens to GFR and ACR as risk of CKD increases?
GFR goes down
ACR increases
What are the home therapies for kidney failure?
Haemodialysis
peritoneal dialysis
