metabolic mc1 Flashcards
define AKI
Increase in serum creatinine by ≥0.3 mg/dL (≥26.5 micromol/L) within 48 hours; or
Increase in serum creatinine to ≥1.5 times baseline, which is known or presumed to have occurred within the prior seven days; or
Urine volume <0.5 mL/kg/h for six hours
what does KDIGO leave out for AKI
GFR (apart from in children)
AKI stage 1
Increase in serum creatinine to 1.5 to 1.9 times baseline, or increase in serum creatinine by ≥0.3 mg/dL (≥26.5 micromol/L), or reduction in urine output to <0.5 mL/kg per hour for 6 to 12 hours.
AKI stage 2
Increase in serum creatinine to 2.0 to 2.9 times baseline, or reduction in urine output to <0.5 mL/kg per hour for ≥12 hours.
AKI stage 3
Increase in serum creatinine to 3.0 times baseline, or increase in serum creatinine to ≥4.0 mg/dL (≥353.6 micromol/L), or reduction in urine output to <0.3 mL/kg per hour for ≥24 hours, or anuria for ≥12 hours, or the initiation of renal replacement therapy, or, in patients <18 years, decrease in eGFR to <35 mL/min per 1.73 m2.
dehydrated AKI treatment/pre renal
IV fluid therapy – fluid challenge = 500 mL 0.9% NaCl over fifteen minutes
Withdrawal of nephrotoxins
Withholding of hypotensive agents and diuretics
Withhold atorvastatin
causes of hyperK
Reduced aldosterone secretion
aldosterone resistance
Reduced distal sodium and water delivery as occurs in effective arterial blood volume depletion
Acute and chronic kidney disease in which one or more of the above factors are present
spironolactone MOA
It competes with aldosterone for receptor sites in the distal renal tubules, increasing sodium chloride and water excretion while conserving potassium and hydrogen ions; may block the effect of aldosterone on arteriolar smooth muscle as well.
spironolactone active metabolite
canrenone
only diuretics that do not act at the luminal membrane of the tubular cells
spiro
eple
what upregulates Enac
ALDOSTERONE
what is required for spiro and epel to work
aldosterone
what enhances the work of spiro and epel
hyperaldosterone
spironolactone indications
Systolic heart failure
Resistant hypertension
Temporary treatment of Conn’s syndrome
Liver failure (oedema)
first line diuretic for ascites with liver failure
spironolactone
would you use spironolactone in primary hyperaldosterone
ye while waiting for surgery/cant have surgery/establishing diagnosis
spironolactone adverse effects
Hyperkalaemia Gynaecomastia Liver impairment Jaundice Stevens–Johnson syndrome (a T cell-mediated hypersensitivity reaction)
when not to use spironolactone
Severe renal impairment
Hyperkalaemia
Addison’s disease
Pregnant or lactating women
why can you use spironolactone in addisons
no aldosterone
why not to use spironolactone in pregos
crosses placenta and milk
spironolactone interactions
ACEi and K supplement
loop diuretics MOA
Inhibits reabsorption of sodium and chloride in the ascending loop of Henle and distal renal tubule, interfering with the chloride-binding co-transport system
what do loop diuretics cause the excretion of
excretion of water, sodium, chloride, magnesium, and calcium.
loop diuretics side effecs
Dehydration Hypotension/Hyponatraemia/Hypokalaemia/Hypochloraemia/Hypocalcaemia/Hypomagnesaemia Metabolic alkalosis Gout Deafness Tinnitus
why do you get tinnitus in loop diuretics
A similar Na+/K+/2Cl− co-transporter is responsible for regulating endolymph composition in the inner ear
main use of loop diuretics
Management of oedema associated with heart failure and hepatic or renal disease; acute pulmonary oedema; treatment of resistant hypertension
how does ramipril become active
saponification
ramipril active metabolite
ramiprilat
why does ramipril have a long duration of action
slow rate of dissociation of enzyme inhibition
how can a CNS mech be involved in lowering BP with ACEi
angiotensin II increases adrenergic outflow from CNS; vasoactive kallikreins may be decreased in conversion to active hormones by ACE inhibitors
indications for ACEi
Hypertension
Symptomatic heart failure
Prophylaxis after myocardial infarction in patients with clinical evidence of heart failure
Prevention of cardiovascular events in patients with atherosclerotic cardiovascular disease or with diabetes mellitus and at least one additional risk factor for cardiovascular disease
ACE adverse effects
Hypotension Hyperkalaemia Cough Worsening renal function Angioedema Anaphylactoid reactions
ACEi interactiosn
ACE inhibitors and ARBs: hyperkalaemia
Potassium supplements and potassium sparing diuretics: hyperkalaemia
NSAIDs: acute kidney injury
pharmacokinetic
drug interactions occur when one drug changes the systemic concentration of another drug, altering ‘how much’ and for ‘how long’ it is present at the site of action
pharmacodynamic
drug interactions occur when interacting drugs have either additive effects, in which case the overall effect is increased, or opposing effects, in which case the overall effect is decreased or even ‘cancelled out’.
how can NSAIDs cause AKI
hemodynamically mediated acute kidney injury (AKI); electrolyte and acid-base disorders; acute interstitial nephritis (AIN)
increase in PG syntheis
Chronic kidney disease
Volume depletion from aggressive diuresis, vomiting, or diarrhoea
Effective arterial volume depletion due to heart failure, nephrotic syndrome, or cirrhosis
Older age
Severe hypercalcaemia with associated renal arteriolar vasoconstriction
gold standard filtration marker
inulin
why is iulin good
freely filtered at the glomerulus, and is neither secreted, reabsorbed, synthesized, nor metabolized by the kidney
bad things about inulin
short supply, expensive, and difficult to assay. continuous intravenous infusion, multiple blood samples, and bladder catheterization
why is cockroft and gault more accurate
includes weight
bad about cockroft and gault
overestimates by 10-14%
what does the MDR formula use
serum creatinine, age, sex, and race
how is renal function measured
eGFR calculated from ‘MDRD formula’
expressed as creatinine clearance
information on dosage adjustment in the BNF is expressed in terms of
eGFR
for txic drugs what should be used to calc dose
creatinine clearance (calculated from the Cockcroft and Gault formula)
what happens to Drug excreted by the kidneys with CKD
Increased half life so longer to reach steady state
how to prescrive with CKD and renal excretion of a drug
Loading dose if needed to reach steady state quickly but lower dose at more frequent intervals
