Renal Failure Flashcards
What are the homeostatic functions of the kidney?
Electrolyte balance
Acid-base balance
Volume homeostasis
What are the endocrine functions of the kidney?
Erythropoietin
1 alpha hydroxylase
What are the excretory functions of the kidney?
Nitrogenous waste Hormones Peptides Middle sized molecules” Salt and water
How is the kidney involved in glucose metabolism?
Gluconeogenesis
Insulin clearance
What happens when the homeostatic function is compromised?
Increase potassium Decreased bicarb Decreased pH Increased phosphate Salt and water imbalance
What happens when the excretory function is compromised?
Increased urea
Increased creatinine
Decreased insulin requirement
What happens when the endocrine function is compromised?
Decreased calcium
Anaemia
Increased PTH - tertiary hyperparathyroidism possible
Overall what does Kidney failure increase risk of?
Cardiovascular problems
What is the clinical presentation related to?
Rate of deterioration
What is the most important thing to asses with renal failure?
Blood volume
What indicates hypovoleamia?
Cold hands
No visible JVP
Reduced capillary refill
Low BP
Why would a patient have a high respiratory rate with normal O2 and clear lungs on auscultation?
Respiratory compensation in response to metabolic acidosis
What is Kussmaul respiration?
Hyperventilation to breathe of CO2
O2 goes up
What is the state of the kidneys in CKD?
Small shrunken kidneys
What is interesting about salt and water balance?
Can cause kidney failure
Can be a symptom
What does kidney failure result in re salt and water?
REDUCE secretion of salt and water leading to:
Hypertension
Oedema
Pulmonary oedema
When might water loss be seen?
salt and water loss may be seen in tubulointerstitial disorders – damage to concentrating mechanism
& hypovolemia may be the cause of AKI.
What do you give to treat hyperkalaemia?
Bicarbonate
To reduce H+
So potassium can return to cell
What causes hyperkalaemia?
↓ Distal tubule potassium secretion
Acidosis
What are the symptoms of hyperkalaemia?
Cardiac arrhythmias
Neural and muscular activity
Vomiting
What do the symptoms of hyperkalemia depend on?
Chronicity
What are the ECG findings for arrhythmias caused by hyperkalaemia?
tented T waves P wave - broadens - - reduced amplitude - - disappears QRS widening Heart block Asystole VT/VF
What does reduced erythropoietin cause?
Anaemia
What does reduced Vit D result in?
Reduced intestinal calcium absorption
Hypocalcaemia
Hyperparathyroidism
What do the effects on metabolism result in?
Increased risk of CVD
What is a major predictor of end stage renal failure?
CKD
BUT
Major outcome for a patient with CKD is cardiovascular disease
i.e. a patient with CKD is more likely to die from cardiovascular disease than end stage renal failure
What are standard cardiovascular risks?
Hypertension
Diabetes
Lipid abnormalities
What are the additional cardiovascular risks in renal faliure?
Inflammation
Oxidative stress
Mineral/bone metabolism disorder
How do you treat hypovolaemia?
Fluids
How do you treat hypervolaemia?
Diuretics if there is sustained urine ouput
Dialysis
How do you treat hyperkalaemia?
Drive into cells
- sodium bicarbonate
- insulin dextrose (caution)
Drive out of the body – diuretics/dialysis
Gut absorption – potassium binders, stay in gut, excreted via faeces
What is the long term conservative management for kidney failure?
- erythropoietin injections to correct anaemia
- diuretics to correct salt water overload
- phosphate binders
- 1.25 vit d supplements
- symptom management
What is the ultimate aim in renal failure?
Transplantation if fit enough
Why would you opt for conservative mangement for renal failure?
Sometime dialysis would not be hugely beneficial
Dialysis is not very pleasant
What home therapy is available?
Heamodialysis
Peritoneal dialysis/Assisted programmes
What in centre therapy is available?
Haemodialysis
4 hours, 3 times a week
How is a fistula created?
Connect artery to vein
Vein swells up - easy to get needles in to
What should be avoided in kidney patients?
Taking blood or IV lines into the veins in the ante-cubital fossa
Avoiding transfusions in transplantable patients
Why do you avoid transfusions?
Sensitisation can risk transplant success
What are the features of using Urea to assess GFR?
Poor indicator
Confounded by diet, catabolic state, GI bleeding (bacterial breakdown of blood in gut), drugs, liver function etc.
What are the features of using Creatinine to assess GFR?
Affected by muscle mass, age, race, sex etc.
Need to look at the patient when interpreting the result. TREND helpful.
What are the features of using Creatinine clearance to assess GFR?
Difficult for elderly patients to collect an accurate sample
Overestimates GFR at low GFR (as a small amount of creatinine is also secreted into urine)
What are the features of using Inulin clearance to assess GFR?
Laborious - used for research purposes only
best way to calculate GFR
What are the features of using radionuclide to assess GFR?
EDTA clearance etc
Reliable but expensive
Used for donated kidneys to check function prior to transplantation
What is the GFR equation? MDRD
GFR (mL/min/1.73m2) = 175 x (SCr)-1.154 x (Age)-0.203 x (0.742 if female) x (1.212 if Afr American)
What is the GFR equation? (CKD-EPI)
GFR = 141 x min (SCr/K,1)-α x max (SCr/K,1)-1.209 x 0.993Age x 1.018 [if female] x 1.159 [if black]
What are the different methods of dialysis?
Haemodialysis
How does haemodilaysis work?
Blood flows into dialyzer
Countercurrent movement (blood and dialysate)
Via diffusion the blood is cleaned
Fresh dialysate is pumped in and used pumped out
Doctor can adjust property of dialysate solution according to the patients need
How does peritoneal dialysis work?
Dialysate pumped into peritoneal cavity
Peritoneum acts as semi-permeable membrane
Diffusion occurs
Dialysiate pumped out via catheter
What are the pros and cons of haemodialysis?
Dialysis centre visits (can be performed at home)
3-4.5 hours of treatment 3x a a week
What are the pros and cons of peritoneal dialysis?
-
What factors are considered in determining a candidate as a suitable live kidney donor?
Patient fitness Good kidney function Psychological assessment Blood type - but you can transplant against blood type Tissues type (HLA, serum crossmatch) Kidney size No blood/protein in urine Financial stability (of work for 4 weeks) Age Future pregnancy Comorbidities Family history of kidney disease
What advice should be given to those post transplant?
Low salt Hygiene No grapefruit Manage BP Use sunscreen Be mindful of psychiatric disorders Regular fluid intake
Why is the old kidney left in situ?
Operative risk of removing is significant
When would you remove the old kidney?
Concern in the native kidney e.g. cancer/TB
Polycystic kidneys - too bug
What should be avoided after having a transplant?
Raw eggs/meat
Undercooked fish and unpasteurised chsses
Seville oranges/marmalade/grapfruit 0 can interact with immunosupressants
No live vaccines
No smoking
No NSAIDS/Herbal meds
No alcohol
What should be avoided after having a transplant?
Raw eggs/meat
Undercooked fish and unpasteurised chsses
Seville oranges/marmalade/grapefruit - can interact with immunosupressants
No live vaccines
No smoking
No NSAIDS/Herbal meds
No alcohol
AKI vs CKD history
acute vs chronic
history of acute illness e.g gastroenteritis vs history of impaired renal function
AKI vs CKD on examination
AKI - acutely ill, SOB, arrythmia, fatigue, nausea, may be hypotensive/acidotic/fluid overload
CKD - signs of anaemia, cachexia, grey skin, weak
AKI vs CKD bloods
AKI - rapidly increasing creatinine, normal calcium, normal-low Hb
CKD - slowly trending increase creatinine, low calcium (untreated), normocytic anaemia
ultrasound AKI vs CKD
AKI - normal
CKD -scarring, smaller kidneys
GFR using renal plasma flow
renal plasma flow x filtration fraction
GFR using filtration coefficient
net ultrafiltration pressure x filtration coefficient
renal clearance calculation
rate of urine production x concentration of urine / concentration of substance in plasma
in mL/min
what are all the functions of the kidneys A WET BED
Acid base balance Water balance Electrolyte balance Toxin removal Blood pressure control Erythropoietin vitamin D metabolism
