Chronic Kidney Disease Flashcards
Functions of the kidney
Body fluid homeostasis Electrolyte balance Excretory function Regulation of vascular tone Acid base homeostasis Endocrine function
Traditional definition of chronic renal failure
Irreversible and significant loss of renal function and thus problems with the functions of the kidneys
Definition of chronic kidney disease
Either the presence of kidney damage (abnormal blood, urine or x ray findings) or GFR <60ml/min/1.7m^3 that is present for >3 months
What are the stages of CKD?
1 - kidney damage / normal or high GFR - GFR > 90
2 - kidney damage / mild reduction in GFR - GFR = 60-89
3a/b - moderately impaired = 45-59, 30-44
4 - severely impaired = 15-29
5 - Advanced or on dialysis = < 15
What does pressure difference in the glomeruli lead to?
Glomerular filtration
What is GFR measured in?
ml/min
What crosses the GBM?
Water
Electrolytes
Urea
Creatinine
What crosses the GBM but is reabsorbed in the proximal tubule?
Glucose
Low molecular weight proteins (a2 microglobulin)
What does not cross the GBM?
Cells (RBCs, WBCs)
High molecular weight proteins (albumin, globulins)
Should there be blood or protein measurable in urine if filtering properly?
No
How is protein in the urine quantified?
Protein creatinine ratio (PCR)
What stage of CKD is most prevalent?
3
What is kidney failure replaced by?
Dialysis
Transplant
Complications of CKD
Acidosis Anaemia Bone disease CVD Death and dialysis Electrolytes Fluid overload Gout HTN Iatrogenic issues
Complications of CKD are more likely with worsening what?
eGFR
What does RRT stand for?
Renal replacement therapy
What is RRT for?
End stage renal disease
Causes of CKD
DM GMN HTN Renovascular disease - renal artery stenosis from atherosclerosis or fibromuscular dysplasia - leads to ischaemic nephropathy Polycystic kidney disease Myeloma IgA nephropathy Nephrocalcinosis Sarcoidosis Chronic exposure to nephrotoxins (NSAIDs, lithium, lead, certain herbs) Reflux nephropathy Chronic obstructive nephropathy - prostate disease - metastatic cancer - retroperitoneal fibrosis - PUJ obstruction
Presentation of CKD
Pallor secondary to anaemia of CKD HTN SOB Cognitive changes GI symptoms - Anorexia - vomiting - taste disturbance - uraemic odour Polyuria Nocturia Frothy urine Haematuria Proteinuria Peripheral oedema Itch Cramps
When are cramps mostly common in CKD?
At night
Why do cramps occur in CKD?
Neuronal irritation caused by the biochemical abnormalities of CKD
Investigations of CKD
USS XRAY CT MRI Bloods + blood film Biochemistry Coagulation screen Urine protein:creatinine ratio CK Anti-GBM ANCA or ELISA C3, C4, auto antibody scren
USS advantages
Non invasive
Non ionising radiation
May provide info about chronicity of renal disease
No functional data
Can be used to detect progressive obstruction
What are key goals of treatment of CKD?
Slowing the rate of decline
Assessment of complications related to reduced GFR
How is it possible to slow the rate of renal decline in CKD?
BP control Control proteinuria Treat causes Allopurinol Dietary protein restriction Fish oils Lipid lowering Control acidosis
What is high BP associated with in CKD?
Faster decline in GFR
Investigations of the complications of CKD
Bicarbonate, pH (acidosis)
Blood count, film, haemantics (anaemia)
Calcium phosphate albumin parathyroid hormone (bone disease)
Electrolytes including K (electrolytes)
Exam including BP, oedema, JVP, CXR (fluid overload)
BP +/- 24 hour tape (HTN)
Ask about medication (iatrogenic issues)
What GFR level would metabolic acidosis be seen in?
<20mls/min
What does metabolic acidosis worsen?
Hyperkalaemia
Renal bone disease
Treatment of metabolic acidosis
Oral Na Bicarbonate
What GFR does anaemia usually manifest at?
< 20mls/min
What type of anaemia is seen in renal disease?
Normochromic normocytic
What does reduced GFR have an effect on phosphate?
Hyperphosphatemia
Effect of CKD on vitamin D
Loss of renal tissue Lack of activated vit D Low 1a hydroxylation in CKD, so low activation of vit D Low Vit D levels lead to low calcium - reduced intestinal absorption - reduced tubular resorption
Management of renal bone disease
Control phosphate
- diet
- phosphate binders
- CaCO3, Ca acetate, sevelamer, lanthanum
Normalise calcium and PTH
- active vit D analogues (calcitriol)
- tertiary disease; parathyroidectomy and calcimetrics (cinacalet)
What is potassium normally excreted with in the distal tubule?
Na+
What happens to Na+ excretion as GFR falls?
Reduced delivery of Na+ to distal tubule as GFR falls
What level of K+ may induce fatal cardiac arrhythmia?
> 7mmol/l
Treatment of hyperkalaemia
Acute - stabilise - calcium gluconate - shift = salbutamol + insulin dextrose - Remove dialysis and calcium resonium Chronic - diet - drug modifications
Examples of high potassium foods
Avocadoes Bananas Mangoes Kiwi Oranges Peas Pumpkins Sweet potatoes Tomatoes Ice cream Milk Dairy Chocolate Seeds and nuts
Examples of food that contain low potassium
Apples Berries Grapes Watermelon Carrots Lettuce Onion Unsalted popcorn
At what GFR is fluid/volume overload usually problematic?
GFR < 20mls/min
Why do people get volume overload?
Unable to excrete an excess Na+ load
What does volume overload lead to?
Oedema
Hypertension
Treatment of volume/fluid overload
Na+ restriction
Fluid restriction
Loop diuretics
What is HTN as a complication of CKD often assosiated with?
Volume overload
What BP is aimed for in CKD with and without proteinuria?
With - < 125/75
Without - 130/80
What does a build up of urea toxin lead to?
Uraemic pericarditis
Management of acidosis due to reduced GFR
Bicarb
Management of anaemia due to reduced GFR
EPO
Iron
Management of CV risk due to reduced GFR
BP Drugs Aspirin Cholesterol Exercise Weight loss
Management of risk of dialysis and death due to reduced GFR
Counsel and prepare
Management of electrolyte imbalance due to reduced GFR
Diet
Consider drugs
Management of fluid overload
Salt and fluid restriction
Diuretics
Modalities of renal replacement therapy
Haemodialysis
Peritoneal dialysis
Transplant
Conservative care
How many stages are there of CKD?
5
What are the stages of CKD according to their GFR levels?
Stage 1 - GFR > 90 Stage 2 - GFR 60 - 90 Stage 3a - GFR 45 - 60 Stage 3b - GFR - 30 - 45 Stage 4 - GFR - 15 - 30 Stage 5 - GFR - 0 - 15
What level of GFR cannot be measured above?
> 60
What is erythropoietin released by and in response to what?
Kidney
In response to cellular hypoxia
What are the main uses of erythropoieitin as treatment?
Treat anaemia associated with CKD
Treat anaemia associated with cytotoxic therapy
S/Es of erythropoietin treatment
Accelerated HTN potentially leading to encephalopathy and seizures (BP increases in 25% of patients)
Bone aches
Flu like symptoms
Skin rashes, urticaria
Pure red cell aplasia (due to Abs against erythropoietin)
Raised PCV increases the risk of thrombosis (e.g. fistula)
Iron deficiency 2ndry to increased erythroporesis
What is the angion gap used for?
To classify metabolic acidosis into either
- raised anion gap e.g. seen in DKA
- normal anion gap e.g. seen in patients with diarrhoea due to GI bicarb loss
How to calculate the anion gap
(Na + K) - (Cl + HCO3)
Who is iron deficiency anaemia a worrying sign in?
Elderly
Are erythropoietin injections any use in patients who are iron deficient?
No
How can CKD result in osteomalacia?
Due to high phosphate levels - this ‘drags’ calcium from the bones
If prescribing fluids, what is someones glucose requirements per day? Is this calculated with their weight?
50 - 100g/day
Irrespective of their weight
