0819 - Complications of CKD - RM Flashcards
Briefly outline the epidemiology of CKD
More common >65. Stage III renal impairment in 55%, stage IV in 1.7, and proteinuria in 6.6%.
Dialysis required by 0.1% of population - 35% due to diabetes, 22% due to glomerulonephritis, 14% due to hypertension.
What is the primary Volume related complication of CKD?
Hypertension due to volume overload (can’t pee it off). Put them on an anti-hypertensive ABCD.
ACE-inhibitor, Beta Blocker, Ca++ channel blocker, Diuretic (higher dose to get proper response in CKD)
What is the primary sodium-related complication of CKD?
Urine volume can’t adapt to changes in Na and H2O intake. Can’t concentrate urine and can’t pee off the fluid. In turn, this leads to volume expansion, peripheral oedema, hypertension.
Can present as hypernatraemia (hypertension and heart failure), or hyponatraemia if water intake is excessive. Response to diuretics is poor.
What is the primary potassium-related complication of CKD?
K+ is retained leading to hyperkalaemia. This depolarises cell membranes, leading to cardiac (bradycardia, conduction delays, arrest) and muscular (weakness) problems. Additionally, many drugs cause K+ retention, leading to iatrogenic hyperkalaemia as well.
What normally buffers K+ homeostasis? How is it affected in CKD?
Aldosterone, independent of its volume (Na) function. Remember that K+ is absorbed (PCT/TDL) and secreted (DT/CD). If the kidney is buggered, it can’t do this appropriately.
Aldosterone is salt-sparing and K+ excreting - if it’s switched off, K+ is spared.
How can CKD affect bones?
Ca remains normal, but risk of becoming hypophosphataemic. Normal Ca levels suppress PTH (bone resorption), which also suppresses calcitriol (from kidneys - gut absorption).
If dietary P is taken in, PTH and FGF-23 are stimulated to lower net P levels. However, the released P cannot be excreted, leading to secondary hyperparathyroidism.
Ultimately, Ca and P levels lose homeostasis with each other. Could have anywhere from low to high bone turnover, leading to osteopenia (reduced density).
What are the broad electrolyte complications caused by CKD?
Hypernatraemia - Can’t pee it out, or hyponatraemia in high fluid intake.
Hyperkalaemia - Don’t pee out K+
Acidosis - Don’t pee out H+ - this then intensifies renal damage.
How can CKD cause anaemia?
Kidney produces 90% of erythropoiten (EPO) by sensing hypoxia or haemolysis in kidney. Can’t produce more EPO, so can’t make more RBCs.
