Chronic Kidney Disease Flashcards
CKD
Subtle decrease in function
Greater than 3 months
Kidneys function
Regulate what’s in the blood - remove waste, steady electrolytes, regulate water
Make hormones
Kidney - blood flow
Renal artery - blood enters through this
Goes to glomeruli - filtered - filtrate moves to renal tubule (GFR)
Normal = 100-120 ml/min/1.73m^2 (slightly less in women, decrease in age too)
Hypertension + kidney -> CKD
How?
Kidney - wall thickens - narrow lumen - less blood and oxygen - ischaemic injury - immune cells slip in - growth factors - extra cellular matrix - golmerulo-sclerosis - scarring - chronic kidney disease
Most common cause of CKD?
Diabetes
Excess glucose sticks to proteins (Non-enzymatic glycation)
Efferent arteriolar - stiff and narrow
Obstruction - blood can’t leave glomerulus as easy
Increased pressure - hyperfiltration
Supportive cell - more matrix - expands glomerulus
Glomerulus-sclerosis = CKD
Other causes of CKD (not DM or HTN)
Lupus and RA
Infection (HIV)
Long term use of medications e.g NSAIDS
Toxins e.g. tobacco
High urea in kidney - can cause…
General symptoms e.g. Nausea and loss of appetite Can cause encephalopathy -> asterixis -> coma and death
Pericarditis
Bleeding- less clot formation
Uraemia frost - crystals in skin
Potassium level - kidney
CKD - less potassium excreted, more in blood - hyperkalaemia
Cardiac arrhyhtmias
Calcium levels and the kidney
Kidney activates Vitamin D
Calcium absorption from diet
But in CKD, less activation of Vit D, less calcium in blood = HYPOcalcemia
PTH release - bones lose calcium - resorption - weak and brittle (renal osteodystrophy)
Hormones + the kidney
Low fluid filter - release renin - increase BP
Fall in GFR = more renin = high BP (HTN)
CKD Can cause HTN and can be caused by HTN
Kidney - erythropoietin
Production of RBC from bone marrow stimulation
In CKD, less, so less RBC = anaemia
Diagnosis of CKD
Changes in GFR over time
CKD - GFR under 90
Irreversible kidney damage under 60
Biopsy to confirm (glomerulosclerosis)
Treating CKD
Manage underlying cause
Dialysis
Transplant
Staging of CKD based on GFR
G1: GFR >90mL/minute/1.73m^2 G2: GFR 60 to 89 mL/minute/1.73m^2 G3a: GFR 45 to 59 mL/minute/1.73m^2 G3b: GFR 30 to 44 mL/minute/1.73m^2 G4: GFR 15 to 29 mL/minute/1.73m^2 G5: GFR <15 mL/minute/1.73m^2
Albuminuria - predictor of …
Severe chronic kidney disease
Mild, moderate, severe albuminuria
Albumin to creatinine ratio
Mild - <30mg/g
Moderate - 30 to 300 mg/g (microalbuminuria)
Severe - >300mg/g (macroalbuminuria)
Renal US in CKD
ADPKD - may explain CKD in some people
Smaller kidney + atrophic - CKD
Renal biopsy+serology - look for cause of glomerulonephritis
Tissue under microscope
Different studies can be done
Check ANA + RF, ANKA, HIV, hepatitis
Additional LABS in CKD
High potassium
High phosphate
Low calcium (due to less vit D)
High or Low sodium
Less RBC - normocytic anaemia
High acid, low bicarbonate - ABG - metabolic acidosis likely
Lipid panel to check triglycerides and LDL (go up)
PTH - severe CKD - goes up
In severe CKD - hypercalcaemia may happen if PTH gets high enough!
Treatment for CKD - Reduce progression of the disease
How?
Reduced GFR - activation of renin - increase BP! So, need to decrease BP
ACE inhibitors OR ARBs OR K+ sparring diuretics e.g. Spironolactone
Aim of BP in CKD
130/80 or less than!
HTN - fluid overload prevention, reduction in water loss so fluid retention! - diuretics like loop diuretics
Reduce fluid overload in CKD - how
Water and sodium restriction - reduce fluid retention and overall BP
Diuretics also volume overload
Diabetes - high glucose - causing arteriosclerosis
How to prevent these glucose levels?
Aim of HbA1C ?
Insulin if needed
If type 2, anti diabetic drugs e.g. metformin
Also weight loss, diet changes
Aim of HbA1C <6.5% (48mmol)
Glomerulonephritis - what is this
How to treat?
Damage to the tiny filters inside the kidneys (glomeruli)
Autoimmune diseases may cause this
Treat with steroids/ DMARDs
ADPKD - treat …
Secondary HTN to reduce CKD progression to renal transplant
But ultimately it may lead to this
Renal transplant is often needed in who?
Adults with PCKD
Discontinue … in CKD to halt progression
Nephrotoxic drugs
Treatment of CKD - Renal Replacement Therapies
Dialysis
Kidney transplant
High potassium in CKD - what to give?
Give insulin - potassium in
SABA - beta 2 receptor activation
Bicarbonate in presence of acidosis
Wee out potassium - high dose of diuretic (loop diuretic) +/- thiazide diuretic
Also give fluid if depleted (pull out potassium through bottom, sodium poly stream)
Hyperphosphataemia in CKD
Treat
Phosphate binder - pull phosphate through gut to remove in faeces (prevents absorption)
Low calcium in CKD?
Low vitamin D?
What do we give?
Give calcium!!!
Give vitamin D supplementation
High PTH in CKD? How to treat
More PTH due to low calcium
Increase blood calcium levels sometimes - severe CKD due to hypercalcaemia
But in general, high PTH leading to high calcium levels, address high PTH and high Ca
Secondary hyperparathyroidism (can be tertiary in severe CKD)
To treat - block PTH by giving cinacalcet
If this fails - may have to give a parathyroidectomy!
Cinacalcet - what is this?
Drug which reduces PTH which leads to a decrease in serum calcium conc
Is used in CKD which has high PTH and high Ca levels as a result, helps to bring these down
If it fails - may need to do a parathyroidectomy
Reduce complications of CKD - EPO decreased if kidneys are damaged - RBC low…
How to treat?
We give when Hb is low - if 80-100 or under(roughly) start to treat with EPO
Reduce complications of CKD - inhibit RAAS to prevent HTN worsening (due to elevated renin levels, so secondary HTN)
How?
ACEi
ARBs
Potassium sparring diuretics e.g. eplerenone AND Spironolactone
Aim for 130/80 or lower
Decrease water balance complications in CKD
Reduced GFR
Water retention - fluid overload
Pulmonary oedema, HTN, peripheral oedema
Give diuretics!
Loop diuretic, can add thiazide later to pull off more water
Pull off more - potassium sparing diuretics
Sodium and water restriction is also another way to do this - salt intake reduce, water intake limited, daily weights
Modifications to prevent fluid overload in CKD
Due to reduced GFR, water retention can occur
Leading to fluid overload
Can give diuretics (usually loop, then thiazide, then k+ sparring)
BUT can also do
Daily weights
Reduced salt intake
Fluid restriction!
Acidosis related to CKD - how to reduce the complications of severe acidosis
Retain protons, reduce bicarbonate reabsorption (peed out)
Resulting in acidosis (less than 7.2 = affects cardiac system, electrolyte abnormalities, resistance to vasopressors) warrants treatment with sodium bicarbonate infusion
Albuminuria in CKD - how do we manage this?
Reduce the complications associated with this
Leaky capillaries - albumin in urine - low albumin in blood, leading to third spacing of fluid and increase in lipid synthesis
Decrease in albumin - protect against the protein in urine - ACEi and ARBs can help in proteinuria
Check albumin creatinine ratio - lots of protein in urine, and associated high BP
Put on ACEi or ARB
Complications of these drugs - can increase potassium and bump in creatinine
Reduce complications in CKD associated with high triglycerides and LDLs
Reduce albumin - liver makes TG and LDLs Give STATINS (good therapeutic regimen) Platelet dysfunction - DDAVP (desmopressin) activate platelets and increase activity and induce clots when needed
Worsening CKD:
worsening acidosis / electrolyte abnormalities/ intoxication/ volume overload/ uraemia that is refractory to medical therapy
OR
GFR reducing to stage 4/5, may have to progress to….
Dialysis - may bridge to kidney transplant
GFR reaching … is when transplant+dialysis is planned
When it is about 20 this is when this is planned
When do most people start dialysis?
Around GFR of 12
Conservative care in CKD when GFR is very low?
Dialysis too much, not suitable for transplant, have lots of other conditions