L6-7 - Kidney Disease Flashcards
What is the functional unit of the kidney?
Nephron
What is the glomerulus?
Bundle of capillaries in Bowman’s capsule
What is the glomerular filtration rate (GFR) an indicator of?
Nephron function
What could cause a high glomerular filtration rate (GFR)?
Hypoalbuminaemia, pre-renal arteriole dilation, post-renal arteriole constriction, alcohol
What are the 3 major hormones secreted by the kidneys?
Renin Antidiuretic hormone (ADH) Aldosterone
What are the 2 compartments that bodily water is divided into? Where is this water located?
Extracellular fluid (ECF) - plasma and interstitial fluid Intracellular fluid (ICF) - in cells
Define osmolality
How is this regulated?
Concentration of solvent per unit volume of solute
Na/K pump
What does antidiuretic hormone (ADH) do?
What does it do this in response to?
Stimulates water reabsorption
High ECF osmolality
What does aldosterone do?
What does it do this in response to?
Stimulates Na reabsorption in exchange for K/H ions
Low ECF osmolality
What is the major extracellular cation?
Sodium
What is the major intracellular cation?
Potassium
What general factors can contribute to hyper and hyponatraemia?
Water - Dehydration (hyper) or overhydration (hypo)
Na - Excess (hyper) or reduced (hypo) Na in ECF
What general factors can contribute to hyper and hypokalaemia?
K entering the ECF - Increase (hyper) or decrease (hypo)
Rate of loss - Inefficient secretion (hyper) or increased loss (hypo)
What states/diseases can cause hypernatraemia?
Decreased water intake, increased Na intake, diabetes insipidus, cronn’s syndrome, cushings
What states/diseases can cause hyponatraemia?
Increased water intake, decreased Na intake, renal disease, addisons, SIADH (syndrome of inappropriate ADH)
What states/diseases can cause hyperkalaemia?
Cell damage, acidosis, renal disease, addisons
What states/diseases can cause hypokalaemia?
Decreased K intake, alkalosis, GI losses, Cronns, thiazide diuretics
What renal hormone levels generally result in high Na and/or low K? Give an example for each hormone
Low ADH - diabetes insipidus causes hypernatraemia
High aldosterone - Cronn’s syndrome causes both
What renal hormone levels generally result in low Na and/or high K? Give an example for each hormone
High ADH - SIADH (syndrome of inappropriate ADH) causes hyponatraemia
Low aldosterone - Addison’s causes both
How does acidosis or alkalosis affect potassium levels?
Acidosis - increased H in cells pushes K into ECF (hyperkalaemia)
Alkalosis - decreased H pulls K into ICF to maintain balance (hypokalaemia)
What Na/K levels are seen in renal disease? What causes this?
Hyponatraemia, hyperkalaemia
Reduced urine output
Define the glomerular filtration rate (GFR)
Volume of plasma cleared of a substance per unit time
What two types of substances can be used to measure GFR? Give an example of each
Endogenous - creatinine/urea
Exogenous - inulin
What is the estimated (e)GFR?
Calculated GFR based on serum creatinine levels rather than urine
What are the major biochemical indicators of renal disease?
Serum urea - increased
Serum creatinine - increased
Electrolytes - abnormal
What are the two types of urinalysis?
Physical examination and dipstick test
What does the physical examination part of a urinalysis look at?
Colour - can determine concentration or presence of blood
Turbidity - signs of UTIs or nephrotic syndrome
Microscopy - signs of UTI or glomerulonephritis
What can the dipstick test in a urinalysis indicate in terms of kidney disease?
Proteinuria
What can cause proteinuria?
Kidney disease, infection, stresses, pre-eclampsia
What can imaging be used for in terms of kidney disease? Give two types of imaging
Looking at blockages or some types of kidney damage
X-ray, ultrasound, CT, isotope scan
What can a biopsy be used for in terms of kidney disease?
Aid diagnosis of glomerular disease or kidney damage
What is the most common tubulointerstitial disease? what is this a type of?
Pyelonephritis - type of tubulointerstitial nephritis
What are the signs of pyelonephritis?
Normal urea + creatinine (normal GFR), low K, phosphate, urate and bicarbonate (acidosis)
What syndromes do glomerular diseases present as?
Nephritic or nephrotic syndrome
What are the key differences between nephritic and nephrotic syndrome?
Nephrotic - high proteinuria, caused by non-proliferative glomerulonephritis
Nephritic - slight proteinuria with haematuria, decreased GFR, caused by proliferative glomerulonephritis
What does diabetic nephropathy consist of?
Fibrosis of the glomerulus (glomerulosclerosis) or tubules (tubulointerstitial fibrosis)
What is the difference between acute kidney injury (AKI) and chronic kidney disease (CKD) in terms of time scale?
Acute have rapid onset and decline of GFR, chronic is gradual
What is the difference between acute kidney injury (AKI) and chronic kidney disease (CKD) in terms of prognosis?
Acute - recovery or progression to chronic
Chronic - end stage renal disease and irreversible damage
What are the 3 broad classifications of acute kidney injury (AKI)? What do these consist of?
Pre-renal - issues with blood supply
Renal - damage to kidney
Post-renal - blockage
What are the causes of pre-renal AKI?
3
Decreased plasma volume, decreased cardiac output, renal artery occlusion (blockage)
What are the signs of pre-renal AKI?
Increased urea and creatinine, metabolic acidosis, hyperkalaemia, increased urine osmolality
What are the causes of renal AKI?
2
Glomerulonephritis or acute tubular necrosis
What are the signs of renal AKI (in comparison to pre-renal)?
Lowered serum and urine urea, lowered urine osmolality and increased urine Na
What are the causes of post-renal AKI?
What are the signs of this?
Renal stones or carcinoma of bladder, ovaries or prostate
Decreased urine output, blockage visualised through imaging
What are the 2 major risk factors for chronic kidney disease (CKD)?
Give another 2 risk factors that are less common
Diabetes and high blood pressure
Cardiovascular disease, obesity, high cholesterol, smoking, family history
How many stages of chronic kidney disease (CKD) are there?
How are these classified?
5 stages
Based on declining GFR (1 is highest, 5 is lowest)
What is stage 5 CKD also known as?
End stage renal disease (ESRD)
What are the consequences of CKD?
4
Hyperkalaemia, hypocalcaemia, anaemia, metabolic acidosis
What are the three types of treatment available for CKD?
Conservative care, dialysis, renal transplants
When would it be more appropriate to use conservative care over other CKD treatments?
In those with a poor prognosis for the other treatments e.g. elderly have poor mortality on dialysis
How does dialysis work?
Blood is run through a dialyzer machine filled with wanted molecules; these diffuse into the blood
What is currently a major issue with renal transplants?
There are more people on the waiting list than there are donors - many people die or become too sick to receive the transplant while waiting
