Chronic Kidney Disease L12 Flashcards
What are the functions of the kidneys?
- homeostasis
- excretion of drugs and drug metabolites
- metabolic/endocrine
Which hormones does the kidney synthesise?
EPO, renin, vit D
Why is eGFR a better measure of kidney function than serum creatinine?
takes into account the age, gender, ethinicity of patient as well as serum creatinine level > better measured to population
*two patients of different ages, genders and ethnicities may both have normal serum creatinine but one may have a much higher eGFR than the other. Both eGFRs however may be considered in the normal population eGFR range.
What is Chronic Kidney Disease?
A progressive, irreversible loss of kidney function
Describe the five stages of CKD and the ranges of eGFR they fall into.
Stage 1
- kidney damage, GFR normal
- > 90
Stage 2
- kidney damage, mild decrease in GFR
- 60-89
Stage 3
- moderate decrease in GFR
- 30-59
Stage 4
- severe decrease in GFR
- 15-29
Stage 5
- kidney failure
- <15
What is the definition of stage 5 CKD?
insufficient renal function to sustain life/health
What are options of treatment for someone with stage 5 CKD?
- haemodialysis
- peritoneal dialysis
- kidney tranplantation
-or palliative care leading to death.
What factors increase your risk of getting CKD?
- increased age
- poor education (deprived background)
- hypertension
- diabetes
- smoking
- black or indo-asian ethnicity
Name some of the systemic diseases that can cause CKD.
diabetes, hypertension, atherosclerotic disease
What are some of the immune mediated diseases that can cause CKD?
membranous nephropathy, IgA nephropathy
Give examples of infectious diseases that can cause CKD?
HIV, Hep B, Hep C, TB
what are some genetic diseases that can cause CKD?
polycystic kidneys, cystinosis
Obstruction of the urinary tract can cause CKD due to back-pressure damaging the kidneys. In what ways can the tract be obstructed?
- stones (kidney,bladder)
- benign prostate
- tumours - intrinsic or extrinsic
- fibrosis (of walls etc.)
What is diabetic nephropathy?
progressive damage to kidneys seem in some people with long-standing diabetes. Excessive leakage of protein into urine is followed by gradual decline of kidney function and even kidney failure. Can be prevented/reversed before completely lose kidney function. Pathology includes thickening of basement membrane, mesangial expansion and glomerulosclerosis.
What are some of the complications of CKD?
- anaemia
- cardiovascular disease
- bone disease
- hypertension
- bleeding tendency
- disturbed calcium/phosphate homeostasis
- immune suppression
- abnormal handling of drugs
- complications of treatment
What are the consequences of a loss of fluid homeostasis due to CKD?
- inability to produce concentrated urine
>loss of diurnal rhythm of urine excretion
>increased production of urine from intact glomeruli through osmosis
>limited rate of water excretion - inability to excrete water load
>dilution hyponatraemia
>oedema (pitting, pulmonary etc)
>hypertension
what is the treatment for fluid overload?
- (loop) diuretics
- salt restriction
- fluid restriction (800ml-1L per day)
- if all else fails: dialysis/transplantation
CKD can cause sodium imbalance due to loss of functional nephrons. Why is this a serious issue?
- can get hypertension and fluid overload as unable to excrete sodium and water
- problems with neurological function*
- leads to confusion, muscle spasms, fits and coma
*hypernatraemia > brain cell shrinkage
At what GFR is a patient classed as severely hyperkalaemic?
<10ml/min
What symptoms do patients with hyperkalaemia present?
- cardiac arrhythmias
- muscle fatigue
- weakness
- paralysis
What is the treatment to prevent hyperkalaemia and hypernatraemia?
- salt restriction
- potassium restrcition
- if all else fails: dialysis/transplantation
CKD can lead to metabolic acidosis. What are the symptoms?
- increased respiratory drive > breathlessness
- chest pain
- confusion
- bone pain
- demineralisation of bone
What is the treatment for metabolic acidosis?
- sodium bicarbonate*
- if all else fails: dialysis/transplantation
*however leads to increased Na+ which we don’t want
Recall the kidneys role in calcium homeostasis.
converts 25-hydroxyvitamin D into active 1,25-dihydroxyvitamin D
What is the effect of CKD on calcium homeostasis?
-not producing active vit D
>cannot reabsorb Ca2+ from gut
>bone demineralisation (reabsorb from bone when can’t from gut)
-decrease Ca2+ also affects muscle and cardiac function*
*body would rather maintain serum Ca2+ levels rather than bone structure as Ca2+ is needed critically for these functions
What is ectopic calcification?
Calcium deposition in regions in the body abnormally
- soft tissues
- arteries>become rigid >effects on circulation/perfusion
What treatment prevents bone disease and ectopic calcification?
- 1alpha-hydroxylated vit D replacement
- phosphate restriction (dairy, meat)*
- phosphate binders
- calcimimetics- act on PTH to inhibit secretion
- if all else fails: parathyroidectomy
*remember phosphate reduces serum Ca2+ (by forming insoluble calcium phosphate)
What effect does CKD have on EPO production?
-decreases production
>decreased erythropoiesis > anaemia > symptoms (lethargy, impaired cognition)
>increased risk of LV hypertrophy
>increased risk of CV disease (for ppl with BOTH anaemia and CKD)
What is the treatment for renal anaemia?
recombinant erythropoeitin
Why do patients with CKD get hypertension?
- sodium retention
- volume expansion
- increased stimulation of RAA system
- increased sympathetic NS activity
- endothelial disfunction
*all lead to accelerated decline of kidney function and increased CV risk
What is the treatment for hypertension in CKD?
- salt restriction
- diuretics
- RAS blockade
- other anti-hypertensive medication
What is uraemia?
increased levels of urea, phosphate and other nitrogenous waste in the blood due to decreased kidney function
What is the treatment for uraemia?
dialysis or transplantation
NOT protein restriction as malnutrition
Kidneys are responsible fro removal of drugs from body. In CKD this function can be impaired leading to different problems depending on the drug. What is the treatment to prevent drug toxicity?
modify prescription according to renal function
