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
