Chronic Renal Disease Flashcards
Current CKD definition?
Either the presence of kidney damage (abnormal blood, urine or x-ray findings)
OR
GFR<60 ml/min/1.73m2 that is present for ≥3 months
Classification of chronic renal failure?
Stage 1: GFR> 90
2: 60-89
3a: 45-59
3b: 30-44
4: 16-29
5: <15
How do we measure GFR?
Use serum creatinine to formulate an estimated GFR
When will creatinine start to rise in serum?
When 60% of renal function is lost
Why do black patients have a higher serum creatinine even at normal creatinine clearance ?
Higher muscle mass
Other ways to assess if the kidney is filtering correctly?
Checking blood or protein in the urine - should be NONE
Other ways to look at kidney function?
Looking at anatomy via radiography or histology
Prevalence of CKD?
Increases with age
8-12% in UK
Name some common causes of CKD.
DM
Hypertension
Name some less common causes.
GN Polycystic kidney disease Pyelonephritis SLE Myeloma and amyloidosis
Relevent Hx from a CKD patient?
Past UTIs Hypertension and DM FHx DHx Ureamic symptoms
Investigations for CKD?
Blood
Urine
Imaging
What will x-rays help show?
If patient has renal osteodystrophy - pseudofractures
What will you want to look for in urine?
PCR or ACR (protein/albumin creatinine ratio’s)
Blood
What are uraemic symptoms?
Nausea, anorexia, vomiting
Pruritus
Weight loss
Weakness, fatigue and drowsiness
What sort of drugs can cause CKD?
NSAIDs
Penicillins/aminoglycosides
Chemotherapeutic drugs
ACEIs/ARBs
Why is ultrasound a good investigation?
Non-invasive
No ionising radiation
Can give information about disease/ if there is an underlying cause
Negatives about the ultrasound?
Depends on how good the operator is and doesn’t have any functional data
What are the main ways we slow the rate of renal decline?
BP control - high BP = faster rate of decline
Control proteinuria
Reverse contributing factors/treat causes
List complications due to a low GFR.
Acidosis Anemia Bone disease CV risk Death and dialysis Electrolyte imbalance Fluid overload Gout Hypertension
When is metabolic acidosis seen ?
When GFR<20mls/min
What does metabolic acidosis contribute to?
worsening hyperkalemia and renal bone disease
How to treat metabolic acidosis?
Oral Na Bicarbonate
When is anemia seen?
When GFR<20mls/min
Why does anemia happen?
Renal disease causes reduced erythropoietin production and RBC survival
Treating anemia?
Iron
ESA therapy -Erythropoietin stimulating agents
Features of renal osteodystrophy?
Osteoporosis due to reduced bone density
Osteomalacia (softening of bone) due to reduced mineralization of osteoid matrix
What causes renal osteodystrophy?
Reduction of GFR = hyperphosphateaemia
Loss of renal tissue = lack of activated Vit. D
Usually - Vit. D is activated by the enzyme 1α hydroxylase in the kidney but in CKD this enzyme is low
This leads to a reduction of calcium reabsorption
Why does reduction of GFR = hyperphosphatemia?
The majority of phosphate that comes into the body is then excreted through the kidneys.
If the kidneys are not working so well phosphate will build
What effect does low calcium and high phosphate have on the endocrine system?
Stimulates parathyroid glands to make more PTH - 2y hyperparathyroidism to try and correct imbalance
Prolonged secretion can cause 3y hyperparathyroidism
What does a high phosphate do to the CVS?
Causes vascular and cardiac calcification
What does a high PTH do to bones?
Increases activity of oesteoclasts and osteoblasts which increases bone turnover
Management of renal bone disease?
Control phosphate via diet and phosphate binders
Normalise Ca and PTH - active Vitamin D analogues like calcitrol
If in 3y hyperparathyroidism - parathyroidectomy and calcimimetics
What is a calcimimetic?
A drug that mimics calciums actions on body
What causes hyperkalemia?
K+ is normally excreted by exchange with Na+ in distal tubule
But reduced GFR = reduced delivery of Na+ to distal tubule
Acute hyperkalemia treatment?
Stabalise - calcium gluconate
Shift - salbutamol, insulin-dextrose
Remove - dialysis, calcium resonium
Chronic hyperkalaemia treatment?
Diet and drug modifications
What is fluid overload?
When you are unable to excrete excess Na+ load causing sodium and water retention —> oedema and hypertension
Treatment for overload?
Sodium and fluid restriction
Loop diuretics
What is the ideal BP in CKD?
Aim for <125/75 if sign proteinuria
If CDk with no proteinura - 130/80
What needs to be considered about drugs/toxins in CKD?
Kidney cannot excrete drugs and toxins as well - beware antibiotics, morphine, digoxin, metformin
What drugs can cause AKi on top of CKD?
Contrast agents
Antibiotics
