Week 11 Flashcards
What is CKD
Irreversible, and sometimes progressive, loss of renal function over a period of months to years
Macroscopic appearance of kidneys in CKD
Shrunken
Irregular outline
Thin cortex
Histological appearance of kidneys in CKD
Tubule loss
Interstitial fibrosis
Glomerulosclerosis
Causes of CKD
Majority of patients have a combination of: Infection - pyelonephritis Genetics - Alports Immunological - glomerulonephritis Obstruction Hypertension Vascular disease Systemic disease - diabetes, myeloma
Demographics of CKD
Elderly
Comorbidities
Ethnic minorities
Socially disadvantaged groups
How can CKD be classified
By:
GFR
Albumin creatinine ratio
Stages of CKD classified by GFR
G1 - >90ml/min/1.73m2 G2 - 60-89 G3 - 30-59 G4 - 15-29 G5 - <15 or renal replacement therapy
Which G stages are symptomatic
G4-5
G3 can be symptomatic or asymptomatic
Which G stage require hospital admission
G3-5
Which G stages require other evidence of kidney damage and why
G1-2
GFR above 60 is inaccurate
Stages of CKD classified by ACR
A1 - <3
A2 - 3-30
A3 - >30
Investigations for CKD
Urine dipstick - proteinuria increases incidence of end stage renal disease
Measure serum creatinine to calculate eGFR
Why is serum creatinine a bad measure of GFR
Normal serum creatinine when GFR is 40
Dependent on renal function and muscle mass which is affected my sex, ethnicity and age
Limitations of eGFR
Only accurate in adults
Isn’t useful in AKI
Why don’t we measure GFR in clinical practice
Measuring clearance rates is expensive and takes a long time (need to measure 24 hour urine output)
Finding cause of CKD
History Examination - palpable kidneys Autoantibody screen Complement Immunoglobulin Anti neutrophil cytoplasmic antibodies CRP Imaging - USS (hydronephrosis), CT (stones), MRI (renal artery stenosis) If cause not obvious consider biopsy
How to prevent or delay progression of CKD
Exercise Stop smoking Treat diabetes Treat hypertension with ACEi/AT2 antagonists Lower lipids with statins/diet
Complications of CKD and how they are combated in treatment
Increased risk of cardiovascular death - lifestyle factors, ACEi, statins
Acidosis - give oral NHCO3 tablets
Anaemia - erythropoietin injections
Metabolic bone disease
Why do patients with CKD get anaemia
Decreased erythropoietin production and decreased platelet function
Leads to decreased RBC survival and bleeding
Why do patients with CKD develop metabolic bone disease
Low GFR leads to increased phosphate and decreased calcitriol synthesis so hyperparathyroidism occurs
What bone disorder is hyperparathyroidism associated with
Osteitis fibrosa cystica (painful soft bones leading to deformity)
What bone disorder is associated with low calcitriol
Osteomalacia
What occurs to bone at different levels of vitamin D
Deficiency - rickets or osteomalacia
Normal - mineralisation
High - osteoclast activity
What other metabolic bone disorders occur in CKD patients
Rugger jersey spine - sclerosis of end plates so middle of vertebral bodies look greyer
Erosion of terminal phalanges
Calciphylaxis - vascular calcification, thrombosis and skin necrosis
What is end stage renal disease
GFR <15ml/min
Death is likely with out renal replacement therapy
Symptoms of ESRD
Tiredness Difficulty sleeping and concentrating Symptoms of volume overload - oedema, gallop rhythm, raised JVP and high BP Nausea and pruritis due to accumulation of waste products Leg cramps Pruritis Low fertility Increased infections
Why do ESRD patients need dose alterations
Decreased drug elimination
Increased drug sensitivity - more side effects
When do patients need RRT
Renal function declines to a level that’s no longer adequate to support health
Types of RRT
Haemodialysis
Peritoneal dialysis
Renal transplantation
What symptoms suggest dialysis is needed
Volume overload Acidosis Uraemic symptoms Pericarditis Hyperkalaemia
What needs to be done before haemodialysis begins
Create an arteriovenous fistula (connection between an artery and vein) so that venous pressure increases and the vein dilates and develops a muscular wall
Alternative to arteriovenous fistula
Tunnel line
Has a lower infection risk but increased risk of stenosis
What happens in haemodialysis
Venous blood passes through a pump to increase its pressure and an anticoagulant is added
Dialyser contains highly purified H2O across a semipermeable membrane so waste products are removed from the blood
Clean blood is returned to the venous system
Advantages of haemodialysis
Effective
Don’t need to use everyday
Don’t need to manage treatment themselves
Erythropoietin given in haemodialysis fluid
Disadvantages of haemodialysis
Fluid and diet restrictions
Tied to dialysis times
Need 4 hours 3 times a week
Need 19 tablets a day
Contraindications of haemodialysis
Failed vascular access
Heart failure - can’t tolerate removal of blood
Coagulopathy - high chance of bleeding when the needle is used
Complications of haemodialysis
Infection
Steal syndrome - arterial blood enters venous system so get ischaemia in fingers
CVS instability
Feel chronically unwell
What is peritoneal dialysis
Highly purified peritoneal dialysis fluid is put into the peritoneal cavity and the dialysis occurs at the peritoneal membrane
Fluid containing waste products from the blood is drained away and disposed of
Advantages of peritoneal dialysis
Less food and diet restriction Self sufficient Easier to travel CVS stability Less (10) tablets per day
Disadvantages of peritoneal dialysis
Need 4/5 bag a day
High risk of peritonitis
Need to inject erythropoietin
Contraindications of peritoneal dialysis
Failure of peritoneal membrane e.g surgery, adhesions
Unable to (dis)connect bags
Obese or large muscle mass - can’t get enough dialysis fluid
Complications of peritoneal dialysis
Peritonitis (about every 20 months)
Leaks e.g into scrotum or diaphragm
Herniae
Where do kidneys for transplants come from
Live donor
Deceased after brain death
Deceased after circulatory death
Where are kidneys transplanted to
Iliac fossa
Connected to iliac vessels and bladder
What are kidneys matched according to
Tissue match - blood type, HLA
Number of points - time on waiting list, age
Advantages of renal transplants
Less morbidity and mortality
Cheaper
Better QoL
Disadvantages of renal transplant
Life long immunosuppression (side effects, increased infection and malignancy)
Perioperative risk
