B4-087 Renal Physiology VI Flashcards
when sodium is reabsorbed, […] is secreted
potassium
activates the proton pumps
hormone
aldosterone
hyperaldosterone = metabolic alkalosis
how does hypokalemia cause metabolic alkalosis?
- potassium moves out
- H+ moves in to maintain electrical neutrality –> raises blood pH
- also: increased ammonia production
- hypertension
- hypokalemia
- metabolic acidosis
w/ low renin and low aldosterone
Liddle’s syndrome
diuretic that targets ENac
triamterene
treatment for Liddles
why does hyperglycemia cause pseudohyponatremia?
- water is driven by glucose out of cells into ECF
- cause volume expansion
- dilutes sodium in ECF
when sodium goes down, […] goes down
chloride
why is plasma K+ high in acidosis?
acidosis causes K+ to move from cell to ECF in exchange for H+
all the glucose is reabsorbed in the
proximal tubule
glucose is secreted in urine when
surpasses point of saturation
why does acidosis cause hypercalciuria?
acidosis triggers osteoclasts –> high bone turnover –> hypercalciuria –> nephrolithiasis
causes generalize reduction in bone density
how does acidosis cause kidney stones?
hypercalciuria + increased citrate reabsorption
low citrate and high urine pH precipitate stones
treatment of distal renal tubular acidosis
- restore pH with bicarb and sodium citrate
- KCl supplement therapy
- vitamin D/Ca++ for ricketts
produced by mutations that cause hyperactivation of ENac
liddle’s
- high blood pressure
- low renin
- low aldosterone
Liddle’s
what causes pseudohyponatremia in hyperglycemia?
high glucose in plasma pulls water into the ECF, dilutes sodium
metabolic acidosis from renal tubular acidosis type 1 (distal) can be differed from type 2 (proximal) via…?
bicarbonate excretion in urine
bicarbonate release in urine is […] in proximal RTA and […] in distal RTA
increased in proximal
decreased in distal
what favors calcium precipitation in the renal ultrafiltrate?
decrease in citrate in urine
and high pH of urine
how would SIADH affect:
blood pressure:
plasma renin:
aldosterone:
serum Mg2+:
urine Ca2+:
blood pressure: –/increased
plasma renin: low
aldosterone: low
serum Mg2+: –
urine Ca2+: –
how would primary hyperaldosteronism affect:
blood pressure:
plasma renin:
aldosterone:
serum Mg2+:
urine Ca2+:
blood pressure: high
plasma renin: low
aldosterone: high
serum Mg2+: –
urine Ca2+: –
how would Bartter syndrome effect:
blood pressure:
plasma renin:
aldosterone:
serum Mg2+:
urine Ca2+:
blood pressure: –
plasma renin: high
aldosterone: high
serum Mg2+: –
urine Ca2+: high
how would Gitelman syndrome effect:
blood pressure:
plasma renin:
aldosterone:
serum Mg2+:
urine Ca2+:
blood pressure: –
plasma renin: high
aldosterone: high
serum Mg2+: low
urine Ca2+: low
how would Liddle syndrome effect:
blood pressure:
plasma renin:
aldosterone:
serum Mg2+:
urine Ca2+:
blood pressure: high
plasma renin: low
aldosterone: low
serum Mg2+: –
urine Ca2+: –
inability of a-intercalated cells to secrete H+ so no new HCO3 is generated causing metabolic acidosis
distal renal tubular acidosis (type I)
in which type of RTA is urine pH > 5.5?
distal
type I
causes of RTA type 1
distal
- ampho B
- analgesic nephropathy
- congenital abnormalities
- obstruction of urinary tract
- autoimmune disease (SLE)
which type of RTA carries an increased risk of kidney stones?
type I (distal) due to increased urine pH and high bone turnover
defect in PCT bicarb reabsorption causing increased excretion of bicarb in urine
proximal RTA (type 2)
proximal RTA (type II) is caused by
Fanconi
multiple myeloma
carbonic anhydrase inhibitors
which type of RTA carries an increased risk of hypophosphatemic rickets?
proximal
type II
due to hypoaldosteronism or aldosterone resistance
RTA type IV
hyperkalemic tubular acidosis
hypekalemia causes decreased NH3 synthesis in PCT leading to decreased ammonium secretion
RTA type IV
hyperkalemic tubular acidosis
RTA associated with hyperkalemia
RTA type IV
hyperkalemic tubular acidosis
what can cause decreased aldosterone production?
- diabetic hyporeninism
- ACEs/ARBs
- NSAIDs
- heparin
- cyclosporine
type IV RTA
what can cause aldosterone resistance?
- K+ sparing diuretics
- nephropathy due to obstruction
- bactrim
type IV RTA