Acute and Chronic Kidney Disease Flashcards
Acute kidney injury and chronic kidney disease:
- AKI and CKD supersede old terminology of acute and chronic renal failure (pre 2009)
- severe reduction in renal function - many causes
- acute or chronic
- acute - sudeen onset - tends to be reversible whereas
chronic is slow, progressive loss of nephrons and decrease in GFR, not reversible.
Acute kidney injury:
Rapid and sudden deterioration of renal function
• Resuling in retention of metabolic wastes – Azotaemia
• Impaired fluid and electrolyte balance
• Usually develops over hours/days
• Usually follows
– Severe prolonged hypotension
– Hypovolemia
– Exposure to nephrotoxic agent
Acute kidney injury (AKI)
Usually – Decreased urine output (oliguria) • < 400 ml/day (30 ml/h) – Increased serum creatinine – Increase BUN (Blood urea nitrogen) – Usually reversible
Acute kidney injury (AKI) causes - Prerenal? - intrarenal? - postrenal?
Prerenal: impaired blood flow: hypotension, ischemia, low cardiac output, haemorrhage, surgery
intrarenal - acute glomerulonephritis or acute tubular necrosis - aminoglycoside antibiotics
postrenal - urinary tract obstruction
Clinical Progression of Acute kidney injury:
phase one - initiation phase:
- Initiation phase
• Reduced perfusion, renal injury evolving
• Prevention of injury is possible
• Oliguria, sometimes anuria begins within 1 day of precipitating event
• Lasts 1 – 3 weeks
• Increased BUN and plasma
creatinine
• Other manifestations depend on the underlying cause
• Hyperkalemia, hyperphosphatemia
(frome cellular breakdown)
• Fluid retention/edema
• If cardiac disease – symptoms of congestive heart failure
• Nausea, vomiting, fatigue, accompany electrolyte imbalances and uremia
• Poor wound healing
Clinical Progression of Acute kidney injury:
Phase two - Maintenance Phase:
Maintenance Phase
• Period of establish renal injury and dysfunction
• May last weeks to months
• Urine output lowest during this phase
• Serum creatinine increases
• BUN increase
Clinical Progression of Acute kidney injury:
phase three - Recovery phase:
• Interval when renal injury is repaired
• Normal renal function restablished
• Diuresis is common during this phase
– During the diuretic phase the tubules are still recovering secretory and
reabsorptive function
– Na+ and K+ lost in urine
– Risk of hypocalemia is greater
– Volume depletion may ensue, with fluid loss of 3-‐4L/day
– Fluid and electrolyte balance must be carefully monitored
• Decline in serum
creatinine and urea
• Increase in creatinine clearance
• Return to normal function may take 3-‐12 months
• Approximately 30% people do not fully recover normal GFR or tubular function
Chronic kidney disease:
- gradual loss of nephrons until the remainder cannot carry out normal renal function
- slow but irreversible
- results in end stage renal disease
- ESRD requires dialysis or maintenance for survival
progressive loss of renal function with systemic diseases such as hypertension, diabetes mellites or intrinsic kidney diseases
the national kidney foundation definition
- GFR < 60ml/min/1.73m2
chronic kidney disease risk factors:
- intact nephrons can enlarge and increase function - compensate for loss
- one kidney can take overall function: 50% nephron loss and 50% reduction in GFR
- may not see impaired function until 75-80% loss of nephrons
- alterations to nephrons and increased flow may lead to further damage and loss.
chronic kidney disease:
- what is it thought to be associated with?
The progression of CKD is thought to be associated with a common pathogenic process regardless of the initial disease
chronic kidney disease:
- how many stages are there?
-
- 5 stages related to progressive GFR
- replaces “diminished renal reserve” “renal insufficiency” “chronic renal failure” etc..
- internationally agreed classification of chornic kidney disease (CKD) adapted from the national kidney foundation. 3, 5.
- stage description based on GFR (ml/1.73m2)
stages based on GFR in ml/ min/ 1.73m2:
stage 1 - kidney damage with normal (<90) previous or increased GFR 3.3%
stage 2 - kidney damage with mildly decreased GFR (60-89) = 3.0%
stage 3 - modKD, decreased GFR (30-59) =4.3%
stage 4 severeKD, decreased GFR (15-29) = 0.2%
stage 5 - end stage KD/kidney failure (<15 Ml /min/1.73m2
notes for stage 1 and 2
- diagnosis of stage 1 and 2 CKD requires presence of kidney damage for >3 months
- pathological abnormalities of the kidney or abnormalities in the composition of urine such as: — haematuria or proteinuria, or abnormalities in imaging tests (scaring) with decreased GFR (stage 2) or without decreased GFR (stage 1)
stage 1: kidney damage with normal or > GFR
- GFR >75% at least 90ml/min/1.73m2
- evidence of kidney damage without decreased GFR or with increased GFR
- usually no symptoms
- hypertension common
stage 2: mild kidney damage
- asymptomatic, plasma and urine creatinine and urea rising but is normal range, symptoms subtle, hypertension.
- evidence of damage, e.g. in urine
- increasing parathyroid hormone and early
- bone disease
- GFR down to 50%: 60-89 ml/min/1.73m2
- loss may become progressive
stage 3: moderately reduced GFR/moderate kidney damage:
- (GFR - 30%-%0% = 30-59 ml/min)
- may be asymptomatic even with reduction by 70% mild symptoms, hypertension.
- signs of kidney damage and possible signs of other organ dysfunction
- mild azotaemia (raised creatinine and urea)
- anemia (loss of erythoprotein - EPO); polyuria, notaria due to decreased concentrating ability of nephrons
- hypovolaemia, sodium loss, dehydration
- uremia if under stress.
stage 4:
- severely reduced GFR (SF-GFR)
- GFR 10-25%, <30ml/min
- increasing creatinine and urea (azotaemia)
- increased triglycerides
- normal blood volume and concentration not maintained – sodium and water retention.
- oliguria and fluid overload
- load delivered to remaining nephrons too high, cannot reabsorb, excrete or concentrate
stage 4 continued:
Consequence of CKD = hypertension • Increased creatinine, urea, anaemia • Edema, electrolyte imbalances • Metabolic acidosis • When GFR =25% -‐ Hyperkalemia, hyperphosphatemia ,hypercalcemia • Increased renal phosphate secretion • Decreased Vit D synthesis from bone • Increased Ca2+ resorption from b • Decreased Ca2+ absorption from gut • Urine with fixed low specific gravity
stage 4 continued:
- Anaemia due to decreased EPO (erythropoietin)
- lytic bone disease
- new staging indicates uraemia in stage 5 ut changes to organ/system function are progressive throughout CKD, and effects may vary with disease process and its location is the kidney.
- possible alteration in blood coagulability
- frequent infections and risk of malignancy
- raised insulin and lowered thyroid hormone
stage 5: end stage renal disease:
- GFR <15 ml/min/1.73m2; <10%normal
- oliguria or anuria, severe fluid overload
- major disturbances of fluid and electrolytes, e.g: metabolic acidosis, decreased plasma K+ and phosphate
- uraemia, with anorexia, fatigue, pruritic, vomiting, diarrhoea, weight loss
- major disorders of most body systems
- neurological syndromes - e.g. restless legs, hiccups, sleeplessness, weakness.
end stage renal disease continued:
- increased risk of blood coagulation, chronic inflammation
- cardiovascular disorder due to hypertension and dyslipidaemia, calcium deposition
- need to control food and water intake
- after 1 week of untreated renal failure,
- acidotic coma with deep and rapid respiration
- arterial pressure falls rapidly in the last day
- death usually ensues at PH 6.8
treatment options:
- dialysis
- Haemodialysis
- Peritoneal dialysis
- transplantation
