Chronic Kidney Disease Flashcards
Describe the 6 roles of the kidney
- pH homeostasis: sensed by kidney and over few days, intercalating cells secrete more bicarbonate and absorb more acid.
- Epo production: RBC production
- Blood pressure and fluid regulation: through RAAS
- Excretion of by-products of metabolism: drug metabolites, creatinine, potassium, urea, also keeps in plasma proteins and cells.
- Phosphate excretion
- Vitamin D activation: effects on calcium regulation, PTH regulation, bone vasculature and nerve health
Effects of failing kidneys (8)
- Hypertension
- Fluid overload
- Hyperkalaemia and uraemia
- Albuminuria
- CKD:MBD (high phosphate, hypertension and vasculature dysfunction)
- Osteodystrophy
- Acidosis
- Anaemia
Define chronic kidney disease
Abnormalities of the kidney structure of function present for >3months with implications for health
- eGFR <60mL/min/1.73m2 or albuminuria (urine ACR >3mg/mmol)
What is the most common cause of CKD in the UK?
What are the other 2 less common causes?
Diabetes (24%)
Glomerulonephritis (13%)
Hypertension or renovascular disease (11%)
How is CKD classified?
Presence of reduced GFR or evidence of kidney damage G1 = >90 G2 = 60-89 G3 = 45-59 (a) 30-44 (b) G4 = 15-29 G5 = GFR <15
A1 = ACR <3 A2 = ACR 3-30 A3 = ACR >30
How do we diagnose CKD?
Blood test and urine test
eGFR <60ml/min
ACR >3mg/mmol
Presentation of a patient with CKD?
Most patients are asymptomatic and symptoms only present when they are late disease
Symptoms
- Fluid overload (SOB, oedema)
- anorexia, nausea & vomiting
- restless legs syndrome, fatigue, weakness
- pruritis
- amenorrhoea, impotence
- Screening of patients with comorbidities - IHD
- Screening of patients chronically using nephrotoxics - long term ibuprofen
- Occassionally: unexplained haematuria, oedema.
Signs
- Pallor (secondary to anaemia)
- Hypertension
- Fluid overload (raised JVP, peripheral and pulmonary oedema)
- Skin pigmentation
- Excoriation marks
- Peripheral neuropathy
Modifiable and non-modifiable factors which affect the progression of CKD?
Non-modifiable
- underlying cause of renal disease
- race (black patients progress quicker due to activity of RAAS)
modifiable
- BP most important
- level of proteinuria
- exposure to nephrotoxics (gentamycin)
- further renal insults (hypotension or surgery)
- increases in phosphate, anaemia, acidosis or dyslipidemia
- smoking
- glycaemic control if diabetic
3 principles of treatment of CKD
Renoprotection - treat underlying cause and prevent or slow down progression
Treat complications
Plan for renal replacement therapy
Treating/managing CKD
- smoking cessation
- dyslipidemia - healthy diet, exercising, low alcohol, statins
- control BP!
- control proteinuria using ACE-i or ARBs
- Glycaemic control in diabetics HbA1c <48mmol
- Avoid and control exposure to nephrotoxics
- Hyperphosphatemia - diet and refer to dietician to reduce consumption of high phosphate foods or use phosphate binders
- Acidosis - sodium bicarbonate tablets
- Anaemia - replace iron
Why is it important to control BP in those with CKD?
Studies show that patients with tight blood pressure control have fewer strokes, microvascular events & diabetes related deaths. It reduces mortality.
Why is it important to control BP and proteinuria in those with CKD?
Best outcomes are seen in those with BP control and also in those with no proteinuria this means that these patients will not reach end stage kidney disease
Why is glycaemic control important in managing CKD?
Reduction in microvascular complications (25%) and reduction in all other risks by 12%
Treatment of advanced CKD and complications of CKD
- treat salt and water retention - limit water and sodium consumption or use furosemide
- treat hyperkalaemia - medical emergency - calcium gluconate, low potassium diets, potassium binders and correct acidosis
- Treat CKD:MBD - screen PTH, vit D, phosphate, ALP, calcium levels and supplement if needed
- Treat CVD - antiplatelets (low dose aspirin) for those at risk of atherosclerotic events, atorvastatin for primary and secondary prevention
- kidney replacement therapy planning
Name the 3 main types of KRT?
- haemodialysis
- peritoneal dialysis
- kidney transplant
Describe the haemodialysis procedure
- Removal of blood using fistula or catheter in great veins
- Blood is pumped through tubes where heparin is added to prevent blood clotting
- Blood flows through the dialyser and flows against dialysis fluid in the opposite direction. Diffusion of solutes such as sodium, excess fluid and impurites moves down the concentration gradient.
- Cleansed blood leaves dialyser and goes back into body
What are the pros and cons of haemodialysis
pros
- can be started quickly so good in emergencies
- patient doesnt need training
- gives good clearance
cons
- performed in hospital and usually takes 4h sessions 3x a week so can reduce QOL for patient
- patient can feel ‘washed out’
- Issues with vascular access (loss of lines or infection)
Describe the process of peritoneal dialysis
Not as common
- Uses the peritoneum as a semi-permeable membrane.
- Catheter is inserted into the peritoneal cavity through the abdomen and fluid is infused (dialysate which is a glucose solution) and dwells there
- Solutes diffuse slowly across
- It is a continuous process with intermittent drainage and refilling of the peritoneal cavity, performed at home.
pros and cons of periotoneal dialysis
pros
- fits around the patients life
- doesnt require going into hospital
- gentler dialysis with less hypotension
cons
- requires training
- not appropriate for emergency situations
- infections - PD peritonitis and infection of tube
- loss of membrane function overtime
what is the gold standard option for treatment / management of CKD. When is it considered?
Kidney transplant
Should be considered for every patient with or progressing towards G5 kidney disease.
Treatment of choice for kidney failure provided risks do not outweigh benefits, many patients will not meet the shortlist due to multimorbidities or frailty.
Contraindications for kidney transplant
- absolute: cancer with metastases
- temporary: active infection, HIV, unstable CVD
- relative: congestive HF, CVD
What can we use for immunosuppression for those having a kidney transplant?
Combination of drugs can be used monoclonal antibodies - basiliximab which blocks activated T cells Calcineurin inhibitors (tacrolimus) Antimetabolites - mycophenolic acid Glucorticoidsteroids
Pros and cons of kidney transplantation
pros
- near complete physiological correction with the new kidney producing vitamin d, epo etc.
- women can become fertile again
- improved mortality
- better QOL
cons
- supply of organs
- operative risk as major surgery so elderly patients are too high risk for procedure
- surgical risks - bleedingm infection, urinary leaks
- delayed graft rejection up to 40% grafts
- rejection - steroids and immunosuppression needed
- effects of immunosuppression - increased risk of infection, increased risk of cancer (25x), increased risk of CVD. (3-5x).
