Pathology - KIDNEY DISEASE Flashcards
What happens if GFR fails?
If it drops:
- Chronic kidney disease: Longstanding and irreversible drop in GFR (formerly chronic renal failure)
- Acute kidney injury: Sudden and potentially reversible
What happens if GFR rises?
It’s referred to as ‘hyperfiltration’ It can occur:
- Normally: Pregnancy, protein rich meals
- Abnormally: Diabetes (early stage of diabetic neuropathy )
Idenfity 4 ways in which GFR can be measured
- Inulin clearance
- Serum creatinine
- Creatinine clearance
- Tc-99m-DTPA GFR
What is the normal GFR?
90-120ml/min with about 144L/ay
Clinically: How would you determine ‘normal kidney’ function? (What tests would you undergo?)
Normal structure:
- Ultrasound
- CT scan
- IVP
Normal function:
- Serum Creatinine levels
- eGFR
Normal urine:
- Negative dipstick
What is “renal tubular acidosis”?
It is when the kidneys failure to acidify. In which it occurs due to the failure to reabsorb bicarbonate (proximal RTA) or failure to excrete H+ distal (RTA).
Characterized by:
- Alkaline urine
- Systemic acidosis
How would you assess tubular function?
Urine
- Acid urine (urine pH <6) is normal
- Normal protein excretion (<300mg/day). Protein can leak across glomerulus
- No glucose in urine - indicates diabetes or difficulty with tubular function
Serum
- Normal Ca, PO4, K, Na
What is the function of the tubules? and what will happen if the tubules fail?
Function
- Reabsorption - reabsorbs 99% of ultrafiltrate fails
- Secretion - K, H+, NH3
Failure
- Polyuria, as reabsorption of ultrafiltrate fails.
What happens if urine fails to become concentrate?
- This will result in polyuria (excess urine).
- Occurs/seen in diabetes insipidus patients and people after a renal transplantation
How does diabetes insipidus affect urine concentration?
Diabetes insipidus –> failure of ADH to be released –> failure to reabsorb water –> polyuria (excess pee) and polydipsia (excess drinking)
What are some causes of an acute renal injury (ARF)?
- Pre-renal AKI: Shock, dehydration, severe CCF, haemorrhage
- Intra-renal AKI: Glomerulonephritis, rug toxicity
- Post-renal AKI: bladder outlet obstruction (kidney stones, tumours, prostate hypertrophy etc)
Identify some causes of stage 5 kidney disease?
- Glomerulonephritis
- Diabetic nephropathy
- Cystic
- Hypertension/vascular
- Analgesic
- Vesicoureteral reflux
What is the recommended eGFR formula to use? Give examples of other equations which could be used
Recommended: CKD-epi - Its even better than a 24 hour urine collection
Other
- Cockcroft Fault equation
- MDRD equation
CKD = Chronic Kidney Disease
How is chronic kidney disease (CKD) classified and what are the 5 stages?
- GFR <60ml/min for >3months with or without evidence of kidney damage
Stage - eGFR (mls/min) - Stage CRF
Stage 1: >90 Normal
Stage 2: 60 - 89 Mild CRF
Stage 3: 30 - 59 Moerate CRF
Stage 4: 15 - 29 Severe CRF
Stage 5: < 15 ESRF
Identify various evidence of kidney damage which could result in chronic kidney disease
- Microalbuminuria: Urinary albumin excretion of 30-300 mg/day
- Proteinuria: Excess amount of protein in the urine 300mg/day
- Glomerular haematuria: Microhematuria or macrohematuria
- Pathological abnormalities
- Anatomical abnormalities
Identify various cardiovascular complications which could occur as a result of kidney failure
- Hypertension
- Left ventricular hypertrophy (LVH)
- Premature vascular disease
- Increased mortality
Identify various skeletal (bone) complications which could occur as a result of kidney failure
- Hypokalaemia, hyperphosphatemia - secondary hyperparathyroidism
- Vitamin D deficiency - osteomalacia
- Mixed bone disease
- Adynamic bone disease
- Normal Ca, PO4, K, Na
Identify various blood (anemia) complications which could occur as a result of kidney failure
- Erythropoietin deficiency
- Iron deficiency
What is haematuria?
- Microscopic or macroscopic blood present in the urine
- Approx 6% of AUS people have microscopic haematuria
After positive dipstick
- Follow up with CT/cystoscopy for kidney evaluation
What is proteinuria?
- Too much protein in water
- It is an indication that there is a tubular disease
After positive dipstick
- Follow up 24hr urine test
What is polyuria?
- Peeing too much
- Mostly a tubular disorder
- Causes: Drugs (e.g. diuretics), poisons, chronic kidney disease, uncontrolled diabetes
What is glomerulonephritis?
- It is an immune mediated diseases causing inflammatory in the glomerulus and commonly causing CKD –> causing both haematuria and proteinuria
- often microscopic haematuria
- Proteinuria >300mg/day
- rapid or slow deterioration GFR
What is renal colic?
- Sever pain in flank which radiates to iliac fossa and groin
- Cause: kidney stones or ureter stones
- May result in microscopic or macroscopic haematuria.
Identity common structural abnormalities of the kidneys and collecting systems
Simple cysts
- NO CRF, benign, rarely problematic
Vesico-uretric reflux
- Bladder contraction causing reflux into the kidneys –> dilation of the ureters and kidney damage (usually congenital)
ADPKD
- Cyst disease
Pelvi-ureteric junction obstruction
- Blockage of the junction between renal pelvis and ureter can stop kidney function on that side
Renal cancer
- Grawitz tumour - renal carcinoma
Hydronephrosis
- Too much fluid in the collecting system –> dilation of the ureter and kidney structures
