Kidney Failure Flashcards
Causes
- High blood pressure = damage to glomeruli
- Infection like e.coli
- Loss of blood pressure (dehydration/ blood loss/ heart disease as no ultrafiltration)
- Diabetes = high [glucose] so protein lost into filtrate
- Auto-immune diseases = antibodies against tissue
- Crushing injury
Effects of kidney failure
- Increased levels of urea, ions and water in blood
- Shortness of breath
- Reduced volume of urine
- Nausea
- Increase in water potential of blood
Treatments (4)
- Low protein diet
- Drugs
- Dialysis
- Kidney transplants
Protein-controlled diet for kidney disease
- High protein = more urea produced which cannot be removed
- High protein makes blood more acidic
Low NaCl diet for kidney disease
- Excess salt does not need to removed
- High salt causes high blood pressure and more fluid retention
Drugs to reduce [K+] and [Ca2+]
- High [K] = arrhythmias
- Glucose and insulin, with intravenous Ca stabilise heart muscle membranes
- High [Ca] = heart disease, osteoporosis and kidney stones
- Biphosphonates- osteoclasts that break down bone have lower activity = Ca accumulates in bone and less released in blood
Drugs to reduce blood pressure
- Ca channel blockers- dilate vessels
- Beta blockers- reduce effect of adrenalin (increases heart rate + pressure)
- Angiotensin-converting enzyme (ACE) inhibitors and ARB (Receptor blockers) reduces effect of angiotensin (constricts blood vessels)
Haemodialysis
- Blood taken from artery and passed through narrow fibres made from selectively permeable dialysis tubing
- Tubing surrounded by dialysis fluid
- Anticoagulant = prevent clots forming in machine
- Dialysate passes in opposite direction in machine
- Dialysate has same water potential and ion and glucose conc as blood
- Urea and excess water and salt diffuse from blood into dialysate down the conc gradient
Why glucose concentration of dialysis fluid the same?
If lower, glucose would diffuse out of the patient’s blood and would lead to a shortage of glucose in patient
Why is dialysis fluid replaced and in opposite direction?
Replaced to maintain the diffusion and concentration gradient
Countercurrent system to maximise concentration gradient along the length of the tube
Dialysis pros and cons
+ reduced risk of fluctuation in blood content and volume
+ less risk of infection
+ more efficient waste removal
- hours connected to machine
- regular hospital visits
- expensive machinery in short supply
Continuous Ambulatory Peritoneal Dialysis
- Uses peritoneum (layer of tissue lining bottom of abdomen)
- Rich/ extensive capillary network acts as dialysing memb
- Catheter inserted into abdominal cavity and dialysis fluid pass in
- Blood in close contact with fluid so substances pass more easily (short pathway)
- Fluid drained via gravity into empty bag and changed 4 times a day
CAPD pros and cons
+ less time-consuming
+ can be done at home (less hospital visits)
+ less expensive machinery
- fluctuations in blood content and volume
- less efficient removal of salts and urea as not continuously replaced
- risk of peritoneum infection
Kidney transplant
+ Cheaper long term
+ Frequent hospital visits and machine confine time for dialysis
- Shortage of donors (deceased or suffered from circulatory disease)
- Risk of organ rejection
- Immunosuppressant drugs may increase risk of infection
Fistula
- Artery connected to vein
- High blood pressure and vein does not have thick muscular wall
- Swelling
