Chronic kidney disease Flashcards
(24 cards)
Common causes of ESRD
Congenital and inherited - PKD, Alports syndrome
Renovascular disease
Hypertension
Glomerular diseases - IgA nephropathy most common
Interstitial diseases - often drug-induced
Systemic inflammatory diseases - SLE, vasculitis
DM
Unknown - 5-20%
Typical presentation of CKD
Routine blood test - raised urea and creatinine
Hypertension
Proteinuria
Anemia
Rate of change in renal function is relatively constant for an individual - useful prognostic information! - Follow GFR
General symptoms of CKD
Symptoms are usually not present until GFR is below 30 (stage 4-5) when disease is slowly progressive
Nocturia - early symptom
S&S can affect almost all body systems when GFR is below 15-20
Typical symptoms of CKD
Tiredness and breathlessness Pruritus Anorexia Weight loss Nausea and vomiting Further deterioration - hiccups, Kussmaul breathing (due to metabilic acidosis), muscular twitching, fits, drowsiness, coma
Immune dysfunction in CKD
Cellular and humoral is impaired in advanced disease
Increased susceptibility to infection - the second most common cause of death in dialysis patients after CVD
Hematological abnormalities in CKD
Increased bleeding tendency in advanced - cutaneous echymoses and mucosal bleeding. PLT function impaired and BT is prolonged.
Dialysis partially corrects it (due to uremia)
Increased risk of complications from anticoagulants (needed for hemodialysis)
Anemia - common, decreased Epo. Not in PKD (?)
Electrolytes in CKD
Fluid retention common in advanced
Episodic pulmonary edema can happen in earlier stages - especially in renal artery stenosis
Tubulo-interstitiall disease - may develop salt-wasting - need high sodium and water intake
Metabolic acidosis - common. Usually asymptomatic. May increase tissue catabolism and decrease protein synthesis, exacerbate bone disease and rate of decline in renal function
Endocrine function in CKD
Loss of libido - hypogonadismm due to hyperprolactinemia (both genders)
Half-life of insulin is prolonged (reduced tubular metabolism), but also increased insulin resistance and reduced apetite – leads to unpredictable insulin requirement in diabetic patients in advanced CKD
Neurological and muscle function in CKD
Generalized myopathy may occur - poor nutrition, hyperparathyroidism, vitamin D deficiency, disorders of electrolyte metabolism
Muscle cramps are common
Restless leg syndrome - jumpy legs during night
Sensory and motor neuropathy - paresthesia and drop foot - late in the course - unusual due to widespread RRT availability
Cardiovascular disease in CKD
Increased R in stage 3 or more (GFR less than 60) and those with proteinuria or microalbuminuria
LV hypertrophy - caused by hypertension - increased risk of sudden death (dysarrythmia)
Pericarditis - ESRD - pericardial tamponade, constrictive pericarditis
Medial vascular calcification - common, high serum phosphate (stage 3b and above)
Hyperphosphatemia also may cause itching
FGF23 - increases in response to serum phosphate - an independent predictor of mortality in CKD
Metabolic bone disease in CKD
Disturbance of Ca and Ph - almost universal in advanced CKD
Other types of bone disease that mayt occur - osteitis fibrosa cystica, osteomalacia, osteoporosis
Impaired final vitamin D synthesis (renal tubular cell damage and increased FGF23)
Decreased vit D – impair intestinal absorption of calcium – hypocalcemia – increased PTH
Decreased GFR – rised serum Ph
Increased production of FGF23 from osteocytes – phosphate excretion - eventually fail as renal failure progresses – hyperphosphatemia
Rised serum phosphate + calcium – ectopic calcification in blood vessels and other tissues
Hyperparathyroidism in CKD
Often develop parathyroid gland hypertrophy and secondary hyperparathyroidism
Tertiary hyperparathyroidism supervenes in some cases - autonomous production of PTH by enlarged parathyroid glands
Presents with hypercalcemia
Different histology of bone disease in CKD
Osteitis fibrosa cystica - increased bone turnover due to high levels of PTH
Overtreated with vit-D metabolites - low bone turnover (adynamic bone disease)
Overtreatment of hyperphosphatemia - osteomalacia
Main aim of investigation in CKDF
Find underlying cause - may influence treatment
Identify reversible factors that may worsen renal function - hypertension, UT obstruction, nephrotoxic drugs, salt and water depletion
Screen for complications of CKD - anemia and renal osteodystrophy
Screen for cardiovascular risk factors
Referral criteria of CKD to nephrologist
Younger than 40 years old
Stage 4 CKD or worse (less than 30 GFR)
Rapid deterioration in renal function (fall in GFR more than 5-10 over 5 years)
Significant proteinuria - PCR more than 100 mg/mmol
Significant hematuria - after exclusion of UTI, stones, tumors
Aims of management in CKD
Prevent or slow further renal damage
Limit adverse physiological effects of renal impairment on skeleton and on hematopoesis
Treat risk factors for CVD
Prepare for RRT, if appropriate
Antihypertensive therapy in CKD
Lowering of BP slows progression of CKD, decreases R of hypertensive heart failure, stroke, peripheral vascular disease, reduces proteinuria
Goal - 130/80 in uncomplicated, 125/75 in complicated (proteinuria more than 1g/day
May need multiple drugs
Reduction of proteinuria in CKD
Clear relationship btw degree of proteinuria and rate of progression
ACEI and ARB - reduce proteinuria and retard progression of CKD
- Reduce blood pressure as well
- Especially beneficial in CKD with proteinuria or with diabetic nephropathy
- Reduce risk of cardiovascular events and all cause mortality in CKD
- May be an immediate reduction of GFR at initiation (decreases glomerular perfusion pressure). Can be continues as long as reduction in GFR is less than 20% and nonprogressive
- Prescribe to all with proteinuria and diabetic nephropathy (even if no hypertension) as long as hyperkalemia does not occur
Dietary and lifestyle interventions in CKD
Stage 4 - 5 - prevent excessive protein consumption, ensure adequate caloric intake, limit potassium and phosphate intake
Severe protein restriction - not recommended
Stop smoking - slows decline in renal function, reduces CV risk
Exercise and weight loss - may reduce proteinuria, beneficial for CVS
Lipid-lowering therapy in CKD
Hypercholesterolemia - almost universal in patients with significant proteinuria
Increased TGA levels - common in CKD
Reduce vascular events
Control of dyslipidemia with statins may slow rate of progression of renal disease
Treatment of anemia in CKD
Common in GFR less than 30
Recombinant human Epo
Does not influence mortality
Correcting Hg may include extra risk - hypertension, thrombosis
Less effective in presence of iron deficiency, active inflammation, malignancy, aluminium overload (may occur in dialysis)
Maintaining fluid and electrolyte balance in CKD
Fluid retention - limit dietary sodium to 100mmol/day
Loop diuretics - often needed to treat fluid overload
Hyperkalemia - review drug therapy - stop potassium-sparing diuretics, ACEIs, ARBs. Correction of acidosis may be helpful. Limiting potassium intake to 70mmol/day may be needed in late CKD. Potassium binding resins - calcium resonium - useful only shortterm.
Plasma bicarbonate - should be maintained above 22 mmol/L by sodium bicarbonate supplements (1g 3x per day, increasing as required). Alternative is calcium carbonate up to 3 g per day (if sodium bicarbonate cause hypertension, edema)
Renal bone disease treatment in CKD
Active vit D metabolites in patients with hypocalcemia or increased PTH (more than twice upper limit) - goal to reduce PTH to less than 2-4 times upper limit - avoid oversupression and adynamic bone disease
Avoid hypercalcemia!
Hyperphosphatemia - dietary restriction (milk, cheese, eggs, protein) + phosphate-binding drugs - calcium carbonate, aluminium hydoxide, lanthanum carbonate, polymer-based phosphate binders (sevelamer)
Maintain serum phosphate below 1,8 mmol/L
Parathyroidectomy - tertiary hyperparathyroidism. Alternative - calcimimetic agents such as cinacalce - bind to calcium-sensitive receptor and reduce PTH secretion.
Definition of CKD
Irreversible deterioration of renal function
Usually develops over a period of years
Initially only biochemical manifestation
Eventually clinical symptoms and signs of renal failure develops = uremia
ESRD - when death is likely to occur without RRT