CHRONIC KIDNEY DISEASE AND RENAL FAILURE Flashcards
List homeostatic functions of the kidneys
Electrolyte balance
Acid-base balance
Volume homeostasis
List endocrine functions of the kidneys
Erythropoietin
1 alpha-hydroxylase vitamin D
List excretory functions of the kidneys
Nitrogenous waste Hormones Peptides Middle sized molecules Salt and water
List glucose functions of the kidneys
Gluconeogenesis
Insulin clearance
What occurs in kidney failure?
Homeostatic function failure:
- increased potassium
- decreased bicarbonate
- decreased pH
- increased phosphate
- salt and water imbalance
Endocrine function failure:
- hypocalciaemia (decreased 1-25 Vit D)
- anaemia (reduced EPO)
- increased parathyroid hormone (decreased 1-25 Vit D)
Excretory function failure:
- increased urea
- increased creatinine
- decreased insulin requirement
Increased cardiovascular risk
How does a chronic kidney failure present compared to an acute kidney failure?
In chronic, patient might not feel as bad as they’re bodies have had time to adapt to the effects. Small, shrunken kidneys
In acute, the presentation is sudden and obvious. Normal sized kidneys
Underlying causes of the kidney failure will also have their own presentations
How can chronic kidney failure present on examination?
Pale Cold hands Capillary refill decreased Tachypnea/Dyspnea Lethargy, weakness and anorexia Hypotension due to hypovolemia Oedema
Why might a patient with kidney failure be tachypnoeic/ have kussmaul respiration?
Tachypnea indicates metabolic acidosis. This is because patients with kidney failure will have reduced excretion of H+ leading to increased H+ in blood and they don’t have enough HCO3- to neutralise it. Therefore the body tries to reduce H+ by decreasing CO2 via increased respiration rate
Decreasing CO2 forces this equation left to reduce H+
CO2 + H2O –> HCO3- + H+
Will patients with respiratory acidosis have high or low CO2?
High since they aren’t ventilating well which forces the equation right
CO2 + H2O –>
How can acute kidney failure/injury (AKI) present on examination?
Low respiration rate - bradypnoeic Oedema Feeling sick or being sick Diarrhoea Dehydration Peeing less than usual Confusion Drowsiness
Why might hypertension, oedema and pulmonary oedema occur in a patient with kidney failure?
Why might this not happen?
Reduction in salt and water secretion
Salt and water loss maybe seen in tubulointerstitial disorders - damage to concentrating mechanism
Hypovolemia may be the cause of AKI
What does hyponatremia mean?
Sodium level IN BLOOD below normal
Doesn’t necessarily mean reduced total body sodium
How does acidosis from kidney failure cause hyperkalaemia?
Increase in H+ means more H+ influx into cells which forces the intracellular K+ out.
What does acidosis eventually cause?
Anorexia
Muscle catabolism
What are the causes of hyperkalaemia in kidney failure?
Decreased distal tubule potassium secretion
Acidosis
What are the symptoms of in hyperkalaemia?
Cardiac arrhythmias
Neural and muscular activity
Vomiting - to get rid of potassium
Endocrine: helps drive
- Low levels of 1-25 Vit D
- Hypocalcaemia
- Hyperparathyroidism
What ECG changes can be seen in a patient with hyperkalaemia?
Peaked T waves
P wave - broadens/reduced amplitude/absent
QRS widening
Heart block
Asystole
VT/VF
Why is cardiovascular risk important to consider in CKD?
Patient with CKD is more likely to die from cardiovascular disease than end stage renal failure
List the risks of cardiovascular disease
Hypertension Diabetes Lipid abnormalities Inflammation Oxidative stress Mineral/bond metabolism disorder
What is the initial management for a patient with kidney failure?
Fluid balance:
- hypovolaemic - give fluids
- hypervolaemic - diuretics/dialysis if not peeing
Hyperkalaemia:
- Sodium bicarbonate (drive into cells)
- Insulin dextrose (drive into cells)
- Diuretics/dialysis (drive out of body)
- Potassium binders (stops gut absorption)
Why must you be careful when giving insulin dextrose and at what potassium level can you give it?
Risk of fatality due to hypoglycaemia
Only if potassium > 6.5
What is the long term management for a patient with kidney failure?
Conservative treatment:
- EPO injections
- Diuretics
- Phosphate binders
- 1-25 vit d supplements
- Symptom management
Home therapy:
- Haemodialysis
- Peritoneal dialysis
In centre therapy:
- Haemodialysis (4 hours, 3 times a week)
Transplantation
What should transplantable patients with kidney disease avoid?
Transfusions -> sensitisation -> transplant failure
IV lines to antecubital/cephalic veins as it may cause scarring so you can’t do a fistula
What are the methods for assessing GFR and each of their limits?
Urea
- poor indicator as confounded by diet/drugs…
Creatinine
- affected by muscle mass, age, race, sex…
- consider the patient when interpreting result
Creatinine clearance
- Difficult for elderly to collect accurate samples
- Overestimates GFR at low GFR
Insulin clearance
- Laborious (research purposes only)
Radionuclide studies
- Reliable but expensive
- EDTA clearance etc
