what happens when the kidneys stop working

Question 1

what happens when the kidneys stop working

Answer 1

loss of excretory functioin
loss of homeostatic function - K/H/Na
loss of endocrine function
abnormality of glucose homeostasis - endogenous producer of glucose and metaboliser of insulin

Question 2

effect of loss of excretory functioin

Answer 2

accumulation of waste products

Question 3

consequence of loss of homeostatic function

Answer 3

disturbacnce of electrolyte balance
loss of acid-base control
inability to control vol

Question 4

consequence of loss of endocrine function

Answer 4

failure of erythropoietin production

and 1 alpha hydroxylase vit D to make it active

Question 5

consequence of abnormality of glucose homeostasis

Answer 5

decreased gluconeogenesis

Question 6

what affects the symptoms of renal failure

Answer 6

time frame - GFR falls really quick = feel really ill

falls over years = only feel ill at very end

Question 7

what is a cystogram and what does it show

Answer 7

inject dye into the bladder
shows reflex into the kidney that shouldn’t be there
- Vesicoureteral reflux -> Chronic pyelonephritis-> scarred kidneys - the reflux is repaired but still get high BP

Question 8

what does a GFR of 28ml/min mean

Answer 8

only running at 28%

Question 9

signs that show the intervascular volume is low `

Answer 9

pale 
cold hands 
capillary refill prolonged
slow pulse 
poor skin turgor 
low BP 
JVP not visible

Question 10

signs of renal failure from blood results

Answer 10

high urea and creatinine

Question 11

signs of chronic kidney disease

Answer 11

lethargy, weakness, anorexia
low vol = hypotension
elevated plasma urea and creatine - diagnosis of renal failure
ultrasound confirm

Question 12

what causes symptoms of lethargy and anorexia

Answer 12

failure of excretion - accumulation of waste products, hormones, peptides
failure of homeostatsis - acidosis = nausea, hyponatraemia, volume depletion - low BP
failure of endocrine - anaemia

Question 13

what causes a salt and water imbalance

Answer 13

difficulty excreting more common - hypertension, oedema, pulmonary oedema

excess loss - in pt with tubointestinal disorders - concentrating mechanisms have been damaged = dry

osmotic diuresis - high conc small molecular weight eg urea = low bp

Question 14

are serum Na and total body Na levels different

Answer 14

yes

Question 15

what salt dysregulation is associated with kidney disease

Answer 15

hyponatraemia

Question 16

what are the implications of acidosis

Answer 16

caused - decreased excretion of H+ ions and retention of acid bases
buffered by H enter cell - exchange for K = hyperkalaemia
buffer by increasing CO2 loss through lungs - kussmahl respiration - air hunger

worsen anorexia and muscle catabolism = weakness

Question 17

implication of hyperkalaemia

Answer 17

cause - failure of DCT to secrete K
worsened by acidosis

results in arrhythmia - initial loss P wave and bradycardia and arrest
affect neuronal and muscular activity - weakness

clinical features depend on the chronicity of hyperkalaemia

Question 18

ECG with hyperkalaemia

Answer 18

tall tented T wave
lose P wave
broad QRS
-> bradycardia -> asystole `

Question 19

hwo do you treat hyperkalaemia

Answer 19

give Ca intravenously
insulin to drive K into cell
treat acid base

Question 20

effect on metabolic function of kidney

Answer 20

decrease erythropoietin

CKD = low 1-25 Vit D = intestinal Ca absorption, hypocalcaemia (short term) and hypercalcaemia (long term)

increased CHD risk

Question 21

how does CKD -> hyperparathyroidism

Answer 21

phosphate retention -> hypocalcaemia and hyperparathyroidism and low levels of calcitriol

hypocalcaemia and low levels of calcitriol -> hyperparathyroidism

Question 22

what CV risks does CKD cause

Answer 22

hypertension
secondary cardiac effects
endothelial effects
lipid abnormalities

Question 23

difference between acute and chronic kidney disease

Answer 23

acute - renal size unchanged, previously normal creatinine

chronic - renal size OFTEN reduced, previously abnormal creatinine, chronic uraemic symptoms - look at the history

Question 24

how can CKD have normal sized kidneys

Answer 24

DM, myeloma and amyloid preserve size

Question 25

urea to measure GFR

Answer 25

poor confounders: diet (high - meat), catabolic state, GI bleed (high - protein broken by bacteria), drugs, liver func, urine output (urea high if output low)

Question 26

creatinine to measure GFR

Answer 26

``` affected by: muscle mass age race - afro Caribbean>Caucasian > Asian sex ``` need to look at the patient when interpreting the result `

Question 27

creatinine clearance for GFR

Answer 27

difficult to collect sample - especially if elderly | overestimates in value is low - because small amout is secreted into urine

Question 28

inulin clearance to measure GFR

Answer 28

gold standard laborious - invasive and complicated so only used in research

Question 29

radionucleotide studies for measuring GFR

Answer 29

EDTA clearance reliable expensive best gold standard now

Question 30

calculations for GFR

Answer 30

``` eqn automatically calculates GFR from serum creatinine presented ml/min per 1.73 squared easiest eqn uses age and ethnicity variety eqns used - CKD, epi, MORD some eqn use weight, albumin ``` reliable when GFR>60ml/min unreliable in V thin/obese pt

Question 31

describe a table of GFR and ACR categories and risk of adverse outcomes

Answer 31

the risk increases towards the bottom R

Question 32

what are the dietary modifications required

Answer 32

low K diet fluid restriction vit D supplements - prevent hyperparathyroid bone disease

Question 33

ACE inhibitors

Answer 33

reduce ANG2 | lower bp

Question 34

osmotic diuretics

Answer 34

``` glucose and mannitol when in urine increase osmolarity not reabsorbed in distal part smaller osmotic gradient less water reabsorbed ```

Question 35

examples of diuretics

Answer 35

``` osmotic diuretics carbonic anhydrase inhibitors loop diuretics - furosemide thiazides - block Na/cl cotransport K sparing diuretics - amiloride - block Na channels, spironolactone - aldosterone antagonist ```

Question 36

action of carbonic anhydrase inhibitors

Answer 36

inhibit production of protons less to be exported less na reabsorbed in exchange cause increased urinary acidity

Question 37

loop diuretics

Answer 37

``` in ascending limb of loop of henle inhibit triple transporter of Na, cl, k more na in tubular fluid also affect interstitial Na because of this affect 25% diuresis ```

Question 38

thiazides

Answer 38

inhibit Na, Cl transporter | affect 5-10% filtered load

Question 39

K sparing diuretic

Answer 39

inhibit Na Cl cotransporter in principle cell in DCT and collecting duct reduce Na entry reduce Na into blood - through Na K ATPase - less K in inhibit aldosterone = Na not enter or then leave and kl channel inhibited