What is the current definition of chronic renal failure?
•Chronic kidney disease (CKD) is defined by 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
What are the different classifications of chronic kidney disease?
When will creatinine be raised?
Only until about 60% of the total kidney function is lost
Which demographic has a high serum creatinine?
African Americans - because they have a higher muscle mass
What factors are involved in estimating the GFR from serum creatinine?
The vraiables used depend on which formulae you are using
What funtion of the kidney does eGFR measure?
What things cross the GBM?
What things cross the GBM but are reabsorbed in the proximal tubule?
Low molecular weight proteins - a2, microglobulin
What things don't cross the GBM?
Cells (RBC, WBC)
High molecular weight proteins - albumins, globulins
How do we assess the filtration (keep in function) of the kidney -
Check for the presence of blood or protein in the urine
How do we assess the anatomy of the kidney?
What are the complications of CKD?
More likely with worsening eGFR: Vit D deficiencym hyperphosphataemia, hypoalbuminaemia, hyperparathyroidism
What are the different aetiologies of CKD?
Glomerulonephritis (all causes)
Polycystic kidney disease
Chronic exposures to nephrotoxins (NSAIDs, lithium, lead, ceratin herbs)
Reflux nephropathy and scarring
Chronic obstructive nephropathy (prostatic disease, metastatic cancer, retroperitoneal fibrosis, PUJ obstruction
Give examples of renovascular disease
Renal artery stenosis from atherosclerosis of fibromusclular dysplasia
- Leads to ischaemic nephropathy
Persistently decreased renal perfusion - ongoing heart failure and cirrhosis
What are some symptoms and signs of CKD?
Anaemia - pallor and SOB
SOB also caused by fluid overload
Itch and Cramps
GI - anorexia, vomitting, taste disturbance
Peripheral oedema - exacerbated by hypoalbuminaemia - reduced oncotic gradient
What are the important parts of the history to uncover for a patient with potential CKD?
Previous evidence of renal disease
History of systemic diseases
Pre/post renal factors
Previous evidence of renal disease:
- Raised urea/creatinine
- Family History
History of systemic diseases:
- Diabetes mellitus
- Collagen vascular disease (scleroderma, SLE, vasculitis)
- Malignancy (myeloma, breast, lung, lymphoma)
- Sickle cell disease
- Chemotherapeutic drugs
- Narcotic abuse
- ACE i / ARBs
Pre/post renal factors
- Congestive cardiac failure
- Diuretic use
- Nausea, vomiting, diarrhoea
- LUTS / pelvic disease
Uraemic symptoms - THESE ARE IN LEARINNG OUTCOMES
- Nausea, anorexia, vomiting
- Weight loss
- Weakness, fatigue, drowsiness
What are the examinations for CKD?
–Fever, blood pressure
–Orthostatic BP, skin turgor/temperature
–Raised JVP, crepitations, ascites, oedema
–Rash – malar (lupus), purpuric (vasculitis), macular (AIN)
–Cardiac murmurs (endocarditis)
–Bruits, palpable organs
–Livedo reticularis (vasculitis, atheroembolism),
–splinter haemorrhages (endocarditis)
–Absent (vascular disease)
–Bones and joints
- Percussable bladder, enlarged prostate, flank masses
How do we detect the underlying pathology in CKD?
U and E's
Urine PCR or ACR
Histology - renal biopsy
What are the investigations to exclude active disease?
CK - rhabdomyolysis
Urine Protein : Creatinine ratio - intrinsic renal disease
Serum and Urine electrophoresis - myeloma
How do we quantify protein in the urine?
Protein : creatinine ration
Albumin : Creatinine ration
24 hour urine collection
Renal disease is often asymptomatic - only sign may be abnormal BP or urinalysis
What imaging techniques are used in detecting the aetiology of CKD?
•Ultrasound - no functional date, may provide information about chronicity of renal disease
What does bilateral small kidneys with thinned cortices suggest?
Intrinsic disease (glomerulonephritis)
What does unilateral small kidney indicate?
Renal artery disease
What does clubbed calyces and cortical scars suggest?
Reflux with chronic infection or ischaemia
What do large cystic kidneys suggest?
Cystic kidney disease
How do we slow the rate of renal decline?
Blood pressure control (High Bp is associated with faster decline in GFR)
Control proteinuria (ACEi and ARBs)
Reverse other contributing factors - treat causes
–Dietary protein restriction
How do we assess the complications related to reduced GFR?
Death & Dialysis
When is metabollic acidosis normally seen?
•Not usually seen until GFR<20mls/min
•Most marked in tubular-interstitial disease
What are the effects of acidosis on potassium and bone disease?
•Exacerbates renal bone disease
How is acidosis treated?
Treated with oral sodium bicarbonate
What causes anaemia in CKD? When does it occur
Caused by reduced erythropoietin production
Caused by reduced red cell survival
Usually manifests when GFR is less than 20 mls / min
What is the treatment for anaemia that is secondary to chronic renal disease?
Iron replacement therapy
ESA therapy (erythropoeitin stimulating agent)
Oral vs Intravenous
What causes bone disease in chronic kidney disease?
The kidney's function to excrete phosphate is impaired (reduced serum calcium)
The combination of low calcium and high phosphate stimulates PTH - Bone resorption
The kidney has impaired ability to hydroxylate vitamin D (low levels of 1 a hydroxylase- leads the reduced absorption of calcium) - high phosphate results in reduced 1 a hydroxylase - therefore low vitamin D
Liver + cholecalciferol = 25 hydroxycholecalciferol
+kidney = 1,25 dihydroxycholecalciferol
(high phosphate is also associated with vascular and cardiac calcification)
What is the management of renal bone disease?
Control of phosphate:
- Diet - try to reduce phosphate
- Phosphate binders
- Calcium carbonate, ca, Acetate, sevelamer, lanthanum)
Normalise calcium and PTH:
Active vitamin D anologues (calcitrol)
Tertiary disease (parathyroidectomy and celcimetics - cinacalcet)
What is tertiary parathyroidism?
When there is prolonged hypersecretion it can become uncontrolled
Name some cardiovascular risks
•Underlying disease (e.g. diabetes)
•Renal bone disease (perhaps because increased phosphate)
Improve above factors
Where is potassium normally exchanged with sodium?
Normally excreted by exchange with sodium in the distal tubule
How does the delivery of sodium change when GFR falls?
When GFR falls there is reduced delivery of sodium to the distal tubule
How does an ACE i affect potassium levels?
ACE i causes the retention of potassium
What foods are high in potassium?
Seeds and nuts
What level of potassium can induce fatal cardiac arrhythmia?
When potassium is greater than 7mmol/l
What is the treatment for hyperkalaemia?
When us fluid overload a problem?
WHen GFR is less than 20 mls/min
The kidney is unable to excrete and excess sodium load
Leads to sodium and water retention
What are the complications of sodium and water retention?
Oedema and hypertension
What is the treatment for fluid / volume overload?
What is the blood pressure aim for CKD with proteinuria and withour proteinuria?
With - aim for less than 125/75
Without - aim for 130/80
Which drugs cause acute kidney injury on top of CKD?
What is the risk of the build of of urea?
Haemodialysis vs Peritoneal