What happens when the kidneys stop working? Flashcards
What four things happen when the kidneys stop working?
Loss of EXCRETORY function
Loss of HOMEOSTATIC function
Loss of ENDOCRINE function
Abnormality of glucose homeostasis
What are some symptoms of renal failure?
Lethargy
Anorexia
Hypotension
What causes the symptoms of anorexia and lethargy?
Accumulation of nitrogenous waste products
Acidosis
Hyponatremia
Volume depletion
Anaemia
Chronic neurological damage (peripheral neuropathy)
How can the salt and water levels be imbalanced and what are the consequences?
There could be an inability to excrete salt resulting in hypertension, oedema, pulmonary oedema - MOST COMMON.
There could be an inability to decrease salt excretion (i.e. inability to increase reabsorption of salts) leading to volume depletion and low blood pressure.
Why does acidosis tend to aggravate hyperkalaemia?
The excess H+ is buffered by taking it into cells in exchange for K+
So extracellular K+ concentration increases
What is a serious consequence of hyperkalaemia?
It can lead to membrane depolarisation which is sufficiently large for a portion of sodium channels to inactivate and not be able to contribute to the upstroke -> CARDIAC ARRHYTHMIAS, heart block, affected neural and muscular activity
Describe the endocrine functions of the kidney.
The kidneys produce erythropoietin, which stimulates erythropoiesis
The second hydroxylation reaction to produce calcitriol takes place in the kidneys
What effect does renal failure have on these endocrine functions?
There is reduced erythropoietin production leading to ANAEMIA
There is reduced calcitriol production due to phosphate retention which leads to hypocalcaemia and eventually HYPERPARATHYROIDISM
A major predictor of end stage renal failure is chronic kidney disease, but what is a major outcome for patients with chronic kidney disease?
Cardiovascular Disease
State some similarities between acute and chronic kidney disease.
Anorexia
Anaemia
Acidosis
Tendency to hyperkalaemia and hyponatraemia.
State two differences between acute and chronic kidney disease.
Acute = renal size unchanged + previously normal creatinine Chronic = renal size DECREASED + previously ABNORMAL creatinine
What is the initial management plan for someone suffering from kidney disease?
IV saline to correct fluid loss
IV sodium bicarbonate to correct acidosis
IV insulin and dextrose to increase uptake of K+ into cells
Dialysis
What are the methods of estimating GFR?
Urea (poor indicator) Creatinine (has a lot of variables) Creatinine Clearance (difficult in elderly patients to collect an accurate sample) Inulin Clearance (laborious) Radionuclide Studies (Cr EDTA)
