Electrolytes Flashcards

1
Q

HypoK alkalosis causes?

A
If high BP: 
- high aldo low renin: Conn's, GRA
- low aldo low renin: Liddle, AME, Licorice
If normal BP: 
- If FECl < 0.5%: extrarenal hypoVol
- If FECl > 0.5%: Bartter / gitelman
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2
Q

HyperK acidosis causes?

A
if high BP: PHA2
if normal BP:
- high aldo high renin: PHA1
- low aldo high renin: adrenal insufficiency, aldo biosynthesis deficiency
- low aldo low renin: DM, CNI, NSAID
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3
Q

bartter types and features?

A

BS1: NKCC; hypercalciuria, pre-natal onset
BS2: ROMK; hypercalciuria, prenatal onset
BS3: ClCKNB; hypoMg, first decade
BS4: Barttin; SNHL
BS5: CaSR overactivation cause FHH
All: reduce Cl resorption -> TGR reduce -> increase PGE2 -> increase RAAS

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4
Q

bartter MOI?

A

AR

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5
Q

bartter Tx?

A

NSAID (indomethacine 1-3mg/kg/d)
KCl
spirolactone but watch out for hypoVol

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6
Q

gitelman MOI?

A

AR

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7
Q

bartter symptoms?

A

hypoK, alkalosis, hypoVol, polyuria, hypercalciuria and nephrocalcinosis if BS1-2

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8
Q

gitelman cause?

A

SLC12A3 inactivation mutation -> loss of NCCT function

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9
Q

gitelman features?

A

hypoK, alkalosis, hypoMg, polyuria, chondrocalcinosis, sclerochoroidal calcification

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10
Q

gitelman ddx?

A

BS3, HNF1B, EAST, Sjogren, thiazide use

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11
Q

gitelman Tx?

A

KCl and Mg supp, spirolactone if severe

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12
Q

features of EAST?

A

Epilepsy, Ataxia, SNHL, tubulopathy (same as gitelman)

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13
Q

Liddle MOI?

A

AD

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14
Q

Liddle cause?

A

mutation of overactive ENaC

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15
Q

Liddle ddx?

A

GRA, AME, Licorice

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16
Q

AME cause?

A

11 beta hydroxyvitamin dehydrogenase deficiency

reduce cortisol conversion to cortisone thus activate MR

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17
Q

AME MOI?

A

AR

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18
Q

AME feature?

A

hypoK alkalosis high BP low aldo low renin

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19
Q

AME Ix?

A
increase tetrahydrocortisol (THF) or allo-THF to tetrahydrocortisone (THE) level
genetic test
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20
Q

AME Tx?

A

spirolactone / amiloride

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21
Q

GRA MOI?

A

AD

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22
Q

GRA feature?

A

Early HT, hypoK, alkalosis, high BP, low renin, high aldo

prone to ICH

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23
Q

GRA cause?

A

CYP11B1 (11beta hydroxylase for aldo) promoter fuse with CYP11B2 (aldo synthatase) on Ch8 to cause ACTH induced Aldo production

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24
Q

GRA Ix?

A

increased hybrid steroid (18 hydroxycortisol and 18 oxocortisol)

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25
Q

GRA Tx?

A

Pred 2.5 - 5mg daily +/- spirolactone / amiloride

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26
Q

PHA1 MOI?

A

AR or AD

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27
Q

PHA1 cause?

A

ENaC defect, acquired form from obstructive uropathy +/- pyelonephritis

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28
Q

PHA1 features?

A

hyperK, acidosis, normal BP, high renin high aldo, miliary rash from high Na sweet, CF like high salt lung secretion

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29
Q

PHA1 Tx?

A

NS IVF, NaCl and NaHCO3 replacement, Na resin

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30
Q

PHA2 MOI?

A

AD

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31
Q

PHA2 cause?

A

WNK4 inactivating mutation, disinhibit NCCT and ROMK function
WNK1 activating mutation, inhibit WNK4
acquired form by CNI

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32
Q

PHA2 features?

A

hyperK from birth or later, NAGMA, low renin and aldo

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33
Q

PHA2 Tx?

A

Thiazide

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34
Q

NDI MOI?

A

XR, female carrier variable severity

rarely AR / AD

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35
Q

NDI cause?

A
CKD
hypoK, hyperCa
SCD
malnutrition
demeclocycline, Li use (block by amiloride)
pregnancy
AVPR2 mutation
AR / AD AQP2 final effector protein
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36
Q

NDI features?

A

first week of month polyuria, FTT, vomiting
dystrophic calcification in BG
ADHD due to drinking?

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37
Q

NDI Ix?

A

low urine osmo with hyperNa

DDAVP test (limit intake Vol to UO to avoid rapid hypoNa), 0.3mcg/kg IV observe 2 hrs
Uosmo > 800 mOsm/kg normal, remains < 200 diagnostic
infant may < 800 but should > 300

AR / AD still has AVPR2 thus will have BP drop (vasodilatation) and release vWF

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38
Q

NDI ddx?

A

Central DI / habitual polydipsia (ddx by DDAVP normal response)
secondary NDI: Bartter (with polyhydramnios), AME (HT)

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39
Q

NDI Tx?

A

minimize osmotic load by low protein and caloric intake
thiazide (HCT 1-2mg/kgQ12)reduce salt reabsorption -> mild hypoVol -> increase fluid reabsorpton in PT
+/- amiloride to control hypoK
COXi reduce UO

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40
Q

NSIAD cause?

A

gain of function mutation of AVPR2

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41
Q

NSIAD MOI?

A

XD

42
Q

NSIAD features?

A

Uosmo > 100 in hypoNa hypoosmo, but has low vasopressin (vs SIADH)

43
Q

NSIAD Tx?

A

FR, increase osmotic load (e.g. Urea)

AVPR2 blocker not useful due to no vasopressin excess

44
Q

pseudohypoNa cause?

A

solid phase of serum increase by lipid or protein e.g. TG, paraprotein
-> serum osmo normal
direct ion selective potentiometry can measure true aqueous Na activity

45
Q

How to calculate water excess / deficit

A

0.6 x body weight x (1- Na/140) or (Na/140 - 1)

46
Q

hypoNa hypoVol causes?

A

Urine Na > 20 renal loss:
diuretics, MR deficiency, salt losing nephropathy (in GFR < 15, pRTA), Bicarbonaturia with RTA, ketonuria, osmotic diuresis, CSW (BNP increase urine Vol, ddx NSAID: hypoVol)
Urine Na < 20 extra renal loss:
vomitng, diarrhea, third space loss (peritonitis, pancreatitis, ileus in lumen)

47
Q

hypoNa euvolemic cause?

A

addisonism, hypothyroidism, stress, drugs (desmopressin, carbamazepine . SSRI (enhance AVP release), Haldol, MDMA, IVIG) , SIADH

48
Q

hypoNa hypervolemia cause?

A

urine Na > 20: AKI

urine Na < 20: cirrhosis, NS, CHF

49
Q

Causes of SIADH?

A
CA: brochogenic tumor
Lung: pneumonia
CNS: meningoencephalitis, HI
Others: HIV
idiopathic
50
Q

SIADH dx criteria?

A
Sosmo < 270
Uosmo > 100
euvolemia
high urine Na 
no adrenal, thyroid, pituitary, renal insufficiency and diuretics use
51
Q

Tx of hypoNa?

A
acute symptomatic <48hr:
- 3% NaCl 1-2 ml/kg over 60min +/- lasix
chronic symptomatic:
- 3% NaCl 1-2ml/kg/h if seizure +/- lasix
- FR
aim correct < 8mmolLL
chronic asymptomatic:
- FR
- demeclocycline 300 - 600bd (S/E neurotoxic, nephrotoxic, photosensitive, polyuria)
- Urea 15-60g daily 
- NaCl 2-3g +/- lasix
- V2RA
52
Q

How to estimate Na correction rate?

A

Adrogue formula:
Change in serum Na = ((infusate Na + infusate K) - serum Na) / TBW + 1

but did not account for renal and extrarenal loss of free water
may give DDAVP to prevent hypotonic urine

53
Q

NS Na amount?

A

154 mmol/L

54
Q

Tx of CHF induced hypoNa?

A

salt and FR
ACEI, loop diuretics
V2RA

55
Q

hyperNa hypoVol causes?

A

urine NA > 20 renal loss: diuretics, post obstruction, renal disease
urine Na < 20 extra renal:
GI, burn, fistula

56
Q

hyperNa euvolemic cause?

A

renal loss: DI, hypodipsia

extrarenal loss: insensible loss

57
Q

hyperNa hyperVol cause?

A

Na gain:
primary hyperaldo
cushing
hypertonic dialysis, NaCl, hypertonic NaHCO3

58
Q

DI dx?

A

water deprivation test
FR till 3-5% BW loss or 3x hour urine osmo similar
DDAVP given 5 unit SC and measure urine osmo after 60min

normal Uosmo > 800
complete central DI: Uosmo < 300
partial central DI: 300 - 800
NDI: <300
primary polydipsia > 500

after DDAVP NDI no change, CDI increase substantially

59
Q

Diff primary polydipsia and DI?

A

serum osmo < 270 polydipsia

serum osmo > 295 DI

60
Q

CDI causes?

A
Congential: AR / AD (1st year of life)
Acquired
post traumatic
metastatic CA breast, NP, histocytosis, TB, aneurysm, meningioencephalitis
Drugs
GBS
61
Q

CDI Tx?

A

DDAVP 10-20mcg IN Q12-24hr
or PO 0.1-0.8mg Q12hr
+/- chlorpropamide, clofibrate, carbamazepine to potentiate

62
Q

pseudohypoK cause?

A

large number of cell takes up K (acute leukemia)

Px by cooling and rapid separate plasma

63
Q

hypoK workflow?

A

high aldo, insulin, theophylline, hyperT, adrenergic agent use
-> redistribution
Urine K < 20mmol/24hr -ve: GI loss
Urine K > 20mmol/24hr:
- acidotic: RTA1/2, acetozolamide, DKA osmostic diuresis,
- alkalotic:
BP high - Conn’s, Cushing, AME (low renin / aldo), liddle (low renin / aldo), GRA (low renin, high aldo)
BP low - diuretics, hypovolemia, bartter / gitelman,

64
Q

Liddle Dx?

A

genetic test

65
Q

liddle Tx?

A

amiloride

66
Q

hyperK workup?

A

pseudohyperK due to cell lysis, dx by diff K in serum (clotted) and plasma (no clotting)
trancellular shift: BB, insulin insufficiency
reduced GFR: CKD
normal GFR:
- hyporeninemic hypoaldo: DM, Drug: NSAID, BB, CNI
- hypereninemic hypoaldo: adrenal insufficiency, ACEI / ARB, heparin, ketoconazole
- hypereninemic hyperaldo: drug spirloactone, amiloride, septrin, pentamidine, PH1, PH2

67
Q

TTKG calculation?

A

Uk / Sk // Uosm / Sosm

< 7 in hyperK suggest renal K retention

68
Q

hyperCa causes?

A

high PTH: adenoma, hyperplasia, MEN1 / 2A, FHH (AD, inactivating mutation in CaSR)
malignancy: PTHrP, bone metastasis, hemato
granulomatous: TB, sarcoidosis
Vit D intoxication
Endocrine: hyperthyroid, acromegaly, pheochrommocytoma
pseudohyperparathryoid (with short limb, metaphysal chrondrodysplasia, due to PTH1B activating mutation

69
Q

FHH dx?

A

FECa: Uca / Sca // Ucr / Scr < 1%

70
Q

hyperCa sym?

A
fatigue, weakness
constipation
PUD, pancreatitis
polyuria (NDI) 
renal stone
Neuro: headache
conjunctivitis, band keratopathy
short QT
71
Q

hyperCa Tx?

A

NS +/- Lasix
bisphosphonate (pamidronate 15-90mg IV, Zolandronic acid 4mg IV
Calcitonin IV . IN
Denosumab (RANKL Ab)
steroid if VitD / TB / scarcoidosis related
if malignant hyperCa: PG antagoinst (NSAID)
Propanolol if hyperthryoid
cinacalcet / VitD / surgery if 1st hyperPTH

72
Q

Hungry bone syndrome biochem features?

A

hypoPO4 hypoCa hypoMg hyperK

73
Q

hungry bone Tx?

A

Ca: 2-4g oral, IV if symptomatic or < 1.9
oral calcitriol 4mcg/day
avoid replacing PO4 unless extremely low < 0.32

74
Q

hungry bone Px?

A

off paricalcitrol and cinacalcet and PO4 binder
Q8H CaPO4 Q8H checking
start caltrate 1.5g tds, Rocaltrol 0.5mcg bd

75
Q

hypoCa sym?

A

weakness, confusion, paranoia, chvostek, trousseau, parasthesia of lips and extremities, tetany, seizure
chronic hypoCa cataract, brittle nail, transverse grooves, dry skin, absent axillary and pubic hair

76
Q

hypoCa causes?

A

false hypocalcemia (Adj Ca = Ca + (40 - Alb) x 0.025)

low PTH:

  • post parathyroidectomy (hungry bone) / neck dissection / radiation
  • autoimmune polyglandular syndrome
  • infiltration of parathyroid: granulomatous, metastasis, FE overload
  • HIV
  • hypoMg

high PTH:

  • Vit D deficiency (liver, GI, CKD)
  • PTH resistance: pseudohypoparathyroidism
  • loss of Ca from circulation: hyperPO4, pancreatitis, tumor lysis, acute illness

Drug: bone resorption inhibitors (bisphosphonate, calcitonin, denosumab), cinacalcet, foscarnet (complex with Ca), phenytoin (conversion of Vit D to inactive meatbolite, FE poisoning

HypoMg

77
Q

hypoCa Ix?

A

PTH low:

  • low Mg: hypoMg
  • normal Mg: hypoPTH

PTH high:

  • PO4 high: CKD, PTH resistance
  • PO4 low / N: Vit D deficiency
78
Q

MEN1 / 2a / 2b features?

A

MEN1: pituitary adenoma, parathyroid hyperplasia, pancreatic tumor
MEN2a: parathyroid hyperplasia, medullary CA thyroid, phenochromocytoma
MEN2B: mucosal neuroma, marfanoid, medullary CA thyroid, pheochromocytoma

79
Q

hypoCa Tx?

A

IV / PO Ca, Vit D

thiazide if hypoPTH

80
Q

hyperPO4 causes?

A

redued renal excretion:

  • CKD: high PTH and FGF23 to excrete PO4
  • hypoPTH
  • pseudohypoparathyroid
  • Drug: bisphosphonate
  • acromegaly (increase tubular resorption stimulatied by GH and IGF1

increase endogenous supply:
- cell lysis (rhabdo, TLS)
- respi alkalosis
lactic acidosis

increase exogenous supply:

  • PO4 soda
  • Vit D
81
Q

hypoPO4 causes?

A

increase urine loss:

  • hyperPTH
  • Vit D deficiency
  • diuretics
  • steroid use
  • fanconi, dRTA
  • alcoholism
  • post renal transplant (high FGF23)

decrease GI absorption

  • Vit D deficiency
  • malabsorption

intracellular transfer

  • hungry bone
  • respi alkalosis
  • TPN, refeeding

inherited
- X linked hypoPO4 ricket

82
Q

PO4 reference range?

A

1-1.5mmol/L

83
Q

hypoPO4 sym?

A

encephalopathy, hemolysis, thrombocytopenia, respi failure, rhabdomyolysis, cardiomyopathy

84
Q

hypoPO4 Tx?

A

PO / IV replacement

85
Q

hypoMg causes?

A

GI disease:
- malabsorption, SB resection

urinary losses:
polyuric state, acidosis, hyperCA, primary aldosteroid, hyperthyroid, gitelman

Drug cause:
- aminoglycoside, amphotericin, cisplatin, cyclosporin, pentamidine, thiazide, PPI

86
Q

Anion Gap calculation?

A

Na - Cl - HCO3, cut off 12 +/- 2

albumin adjust: adjusted AG = AG + (40 - alb) x 0.25

87
Q

HAGMA causes?

A

ketoacid: DKA / AKA
lactic acidosis: L/D
Substance: methanol, ethylene glycol, panadol, salicylate

88
Q

NAGMA causes?

A

GI cause: diarrhea, ureterosigmoidostomy
Renal cause: RTA1/2/4, CKD
Endocrine: hypoaldo
Drug: NSAID, acetazolamide

89
Q

UAG calculation?

A

UNa + UK - UCl
+: inability to excrete NH4
-: appropriate excretion

if unmeasured ion present e.g. DKA, hippuric acid, bicarbonate
UOG: measured osmo - (2 x (UNa + UK) + Urea + Uglu)
if > 100 mOsmo/kg suggest normal NH4 excretion

90
Q

Diff RTA

A

hyperK: RTA 4

  • urine pH < 5.5 low aldo secretion
  • urine pH > 5.5: CCD abnormality

RTA2: fanconi (euglycemic glucosuria, hypoPO4, hypoUrate, mild proteinuria), urine pH > 5.5

91
Q

causes of RTA2

A
MM, LCDD
hyperPTH
Drug: getamycin, TDF (tenovovir dixoproxil fumarate, avoid by tenovovir alafenamide fumarate)
Lead, cadmium, mercury
TIN: rejection, MCKD
92
Q

RTA1 causes?

A

Autoimmune: Sjogren, PBC, SLE
Drug: amphoB, toluene
Nephrocalcinosis: hyperPTH, VitD
TIN: obstructive uropathy, transplant

93
Q

lactic acidosis cause?

A
type A: hypoperfusion / hypoxia
- shock, CO poisoning, anaemia
type B: other
- Drug: Metformin, salicyclate, ethylene glycol, methanol, propylene glycol, linezolid, propofol, NRTI, isonizid
- thiamine deficiency
- systemic: liver failure, malignancy
- hereditary (G6P)
94
Q

L vs D lactate?

A

D: SB resection / steatorrhea, causing bacterial overgrowth

Tx by low carbo diet and antimicrobial

95
Q

AKA diff DKA?

A

high B hydroxybutyrate to acetoacetate ratio

96
Q

AKA Tx?

A

glucose infusion

97
Q

Ethylene glycol and methanol sym?

A

EG:
0-12: confusion
12-24hr: APO
24-36hr: frank pain, AKI, CA oxalate crystal

methanol:
0-12 asymptomatic
24-36: pancreatitis, retinal edema
48: putamen and white matter hemorrhage

98
Q

ethylene glycol / methanol Tx?

A

fomepizole 15mg/kg IV loading then 10mg /kg Q12H then 15mg/kg Q12H after 48hr
IV ethanol 5/10% solution
HD
HCO3

99
Q

OG calculation?

A

measured osmo - 2x Na + urea + glucose + (1.25 x Ethanol)

high than 10 indicates toxic alcohol

100
Q

metabolic alkalosis workup?

A
Chloride resistance: UCl > 30: aldo excess or aldosteroism, tubular problem (bartter, gitelman)
check renin / aldo
UCl < 10:
renal loss: diuretics
GI loss: vomiting
101
Q

Winter formula

A

1.5 x HCO3 + 8 +/- 2

mmHg to kPa: divided by 7.5

102
Q

delta delta ratio

A

AG - 12 / 24 - HCO3
1 - 2: HAGMA
> 2: Mixed HAGMA + metabolic alkalosis: vomiting, diuretics
< 1: Mixed HAGMA + NAGMA: diarrhea