Renal Flashcards
How much cardiac output is directed towards the kidneys
25%
Where are kidneys located
Retroperitineal
Describe kidney anatomy
Outer - renal cortex
> renal medulla
Renal pelvis (middle)
Ureters > bladder > urethra
How many nephrons per kidney
1 million
Describe nephron anatomy
Afferent (to) and efferent (away) arteroles
Into glomelerus via bowman’s > PCT (urea excrete, reabsorb organic compounds) >
Loop of henle descending(water reabsorption) & ascending (NO water - NA&CL excrete)
Distal convoluted tubule (optional electrolyte control based on hormones)
Normal Glomerular filtration rate (GFR)
> 90
What is filtered in the glomelerus
Almost plasma without red cells or proteins
(Slag of the nephron - absorbs anything as ‘filtrate’ before its specifics are reabsorbed or excreted via tubules
Difference between osmolarity and osmolality
Osmolality - solutes per kg
Osmolarity - solutes per litre
Describe types of AKI with examples
Pre renal: Decreased renal flow (absolute or relative fluid loss - distributive or haemorrhage)
Intra renal:
Acute tubular necrosis
Acute interstitial nephritis
Glomeleronephritis
Rabdo
Post renal:
Obstruction to outflow (kidney stone, BPH)
Diagnosing AKI? And stages
Rise in creatinine
Fall in urine output
Recall stages
1- 1.5-1.9 above baseline (or over 26mmol/L) /0.5ml/kg/hr 6hrs
2. 2-2.9 above baseline / 0.5ml/kg/hr 12 hours
3 3> baseline / <0.3ml/kg/hr for 25 hours or anuria > 12 hours
Management of AKI
Optimise haemodynamics
Correct K+ / electrolytes
Identify /treat cause (pre, int, post)
Medication review
Filter
Prevent reoccurrence
Normal serum potassium
3.5-5
Severe > 6.5
Causes of high or low potassium
Kidney disease, addisonian, acidosis, medication (nsaids, digoxin), salt intake, diarrhoea and vomiting, low magnesium (low k)
Management of hyperkalemia
Stop all K supplements
Protect heart (ecg changes) = calcium
Move K in cells = insulin/glucose infusion (10 units actrapid & 250ml 10% -15 mins)
SLB nebuliser
Bicarb acidosis
Excrete K = treat cause, RRT, lokelma, loop diuretics
Management of hypokalemia and symptoms
Check cause - insulin infusion, alkalosis, salbutamol
Symptoms: cramps, constipation
>3 PO Sando K
< 3 KCL IV 40mmol / litre saline over 6 hours
ECG monitoring
Check mag level
Causes of hypokalemia
GI loss, renal loss (diuresis/ filter), medication (diuretics), alkalosis, refeeding syndrome, insulin, hypo magnesium
Indications for renal replacement therapy
AEIOU - refractory
A- acidosis (metabolic)
E- electrolyte (hyperk- refractory)
I- intoxication - salicylates, lithium, methanol, ethylene glycol, theophyline
O- overload (fluid)
U- uremia (severe- encephalopathy, pericarditis, nausea/ vomiting)
Describe RAS
Low renal blood flow releases
Renin which converts to Angiotensin 1 by angiotensinogin
Angiotensin converting enzyme (ACE) converted 1>2
Angiotensin 2 causes vasoconstriction
4 mechanisms:
1 ^sympathetic tone vasoconstrict
2 petuitaey gland = release ADH ^H20
3 tubules na/cl uptake increase H20
4 adrenal cortex releases aldosterone water retention ENAC channels
Describe atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP)
Released from stretched atrial and ventricles from increase workload / high blood pressure
Inhibits RAS /4 factors
Modulates / suppresses blood pressure
Describe auto regulation
Kidneys ability to autoregulate renal blood flow despite blood pressure changes between 80-200 systolic
Uses hormones
Hormones to manage renal blood flow
Prostaglandin - efferent & afferent arterioles to dilate (fight/flight)
Dopamine - constricts skin & muscle vessels but dilates renal /cardiac vessels
Anti diuretic hormone (ADH/ vasopressin) - peptide hormone from posterior pituitary
Aldosterone- released by adrenal
Erythropoesis- EPO Hormone produced in kidney causes red cell production (CKD pts have EPO injections to stop anemia)
Hyponatraemia symptoms
Lethargy, headache, confusion, fitting, coma
Causes of hyponatraemia
Hypervolemic: CHF, liver disease, kidney disease
Euvolemic: drugs (SSRI), SIADH, polydipsia
(Plasma & urine osmolality)
Hypovolemic: Drugs (diuretics), endocrine, severe diarrhoea/vomiting, sweating, third spacing
Treatment of hyponatraemia
If severe: Hypertonic saline for treatment control.
Correct slowly, not more than 10mmol in first 24 hours and 8mmol following 24hours.
Risk of pontine demyelenstion
Causes of hypernatraemia
Dehydration (diarrhoea, DI, DKA, sweating, diuretics)
Causes of SIADH
Causes of SIADH
