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
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
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
4
Q
bartter MOI?
A
AR
5
Q
bartter Tx?
A
NSAID (indomethacine 1-3mg/kg/d)
KCl
spirolactone but watch out for hypoVol
6
Q
gitelman MOI?
A
AR
7
Q
bartter symptoms?
A
hypoK, alkalosis, hypoVol, polyuria, hypercalciuria and nephrocalcinosis if BS1-2
8
Q
gitelman cause?
A
SLC12A3 inactivation mutation -> loss of NCCT function
9
Q
gitelman features?
A
hypoK, alkalosis, hypoMg, polyuria, chondrocalcinosis, sclerochoroidal calcification
10
Q
gitelman ddx?
A
BS3, HNF1B, EAST, Sjogren, thiazide use
11
Q
gitelman Tx?
A
KCl and Mg supp, spirolactone if severe
12
Q
features of EAST?
A
Epilepsy, Ataxia, SNHL, tubulopathy (same as gitelman)
13
Q
Liddle MOI?
A
AD
14
Q
Liddle cause?
A
mutation of overactive ENaC
15
Q
Liddle ddx?
A
GRA, AME, Licorice
16
Q
AME cause?
A
11 beta hydroxyvitamin dehydrogenase deficiency
reduce cortisol conversion to cortisone thus activate MR
17
Q
AME MOI?
A
AR
18
Q
AME feature?
A
hypoK alkalosis high BP low aldo low renin
19
Q
AME Ix?
A
increase tetrahydrocortisol (THF) or allo-THF to tetrahydrocortisone (THE) level genetic test
20
Q
AME Tx?
A
spirolactone / amiloride
21
Q
GRA MOI?
A
AD
22
Q
GRA feature?
A
Early HT, hypoK, alkalosis, high BP, low renin, high aldo
prone to ICH
23
Q
GRA cause?
A
CYP11B1 (11beta hydroxylase for aldo) promoter fuse with CYP11B2 (aldo synthatase) on Ch8 to cause ACTH induced Aldo production
24
Q
GRA Ix?
A
increased hybrid steroid (18 hydroxycortisol and 18 oxocortisol)
25
GRA Tx?
Pred 2.5 - 5mg daily +/- spirolactone / amiloride
26
PHA1 MOI?
AR or AD
27
PHA1 cause?
ENaC defect, acquired form from obstructive uropathy +/- pyelonephritis
28
PHA1 features?
hyperK, acidosis, normal BP, high renin high aldo, miliary rash from high Na sweet, CF like high salt lung secretion
29
PHA1 Tx?
NS IVF, NaCl and NaHCO3 replacement, Na resin
30
PHA2 MOI?
AD
31
PHA2 cause?
WNK4 inactivating mutation, disinhibit NCCT and ROMK function
WNK1 activating mutation, inhibit WNK4
acquired form by CNI
32
PHA2 features?
hyperK from birth or later, NAGMA, low renin and aldo
33
PHA2 Tx?
Thiazide
34
NDI MOI?
XR, female carrier variable severity
| rarely AR / AD
35
NDI cause?
```
CKD
hypoK, hyperCa
SCD
malnutrition
demeclocycline, Li use (block by amiloride)
pregnancy
AVPR2 mutation
AR / AD AQP2 final effector protein
```
36
NDI features?
first week of month polyuria, FTT, vomiting
dystrophic calcification in BG
ADHD due to drinking?
37
NDI Ix?
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
38
NDI ddx?
Central DI / habitual polydipsia (ddx by DDAVP normal response)
secondary NDI: Bartter (with polyhydramnios), AME (HT)
39
NDI Tx?
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
40
NSIAD cause?
gain of function mutation of AVPR2
41
NSIAD MOI?
XD
42
NSIAD features?
Uosmo > 100 in hypoNa hypoosmo, but has low vasopressin (vs SIADH)
43
NSIAD Tx?
FR, increase osmotic load (e.g. Urea)
| AVPR2 blocker not useful due to no vasopressin excess
44
pseudohypoNa cause?
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
How to calculate water excess / deficit
0.6 x body weight x (1- Na/140) or (Na/140 - 1)
46
hypoNa hypoVol causes?
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
hypoNa euvolemic cause?
addisonism, hypothyroidism, stress, drugs (desmopressin, carbamazepine . SSRI (enhance AVP release), Haldol, MDMA, IVIG) , SIADH
48
hypoNa hypervolemia cause?
urine Na > 20: AKI
| urine Na < 20: cirrhosis, NS, CHF
49
Causes of SIADH?
```
CA: brochogenic tumor
Lung: pneumonia
CNS: meningoencephalitis, HI
Others: HIV
idiopathic
```
50
SIADH dx criteria?
```
Sosmo < 270
Uosmo > 100
euvolemia
high urine Na
no adrenal, thyroid, pituitary, renal insufficiency and diuretics use
```
51
Tx of hypoNa?
```
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
How to estimate Na correction rate?
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
NS Na amount?
154 mmol/L
54
Tx of CHF induced hypoNa?
salt and FR
ACEI, loop diuretics
V2RA
55
hyperNa hypoVol causes?
urine NA > 20 renal loss: diuretics, post obstruction, renal disease
urine Na < 20 extra renal:
GI, burn, fistula
56
hyperNa euvolemic cause?
renal loss: DI, hypodipsia
| extrarenal loss: insensible loss
57
hyperNa hyperVol cause?
Na gain:
primary hyperaldo
cushing
hypertonic dialysis, NaCl, hypertonic NaHCO3
58
DI dx?
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
Diff primary polydipsia and DI?
serum osmo < 270 polydipsia
| serum osmo > 295 DI
60
CDI causes?
```
Congential: AR / AD (1st year of life)
Acquired
post traumatic
metastatic CA breast, NP, histocytosis, TB, aneurysm, meningioencephalitis
Drugs
GBS
```
61
CDI Tx?
DDAVP 10-20mcg IN Q12-24hr
or PO 0.1-0.8mg Q12hr
+/- chlorpropamide, clofibrate, carbamazepine to potentiate
62
pseudohypoK cause?
large number of cell takes up K (acute leukemia)
| Px by cooling and rapid separate plasma
63
hypoK workflow?
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
Liddle Dx?
genetic test
65
liddle Tx?
amiloride
66
hyperK workup?
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
TTKG calculation?
Uk / Sk // Uosm / Sosm
| < 7 in hyperK suggest renal K retention
68
hyperCa causes?
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
FHH dx?
FECa: Uca / Sca // Ucr / Scr < 1%
70
hyperCa sym?
```
fatigue, weakness
constipation
PUD, pancreatitis
polyuria (NDI)
renal stone
Neuro: headache
conjunctivitis, band keratopathy
short QT
```
71
hyperCa Tx?
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
Hungry bone syndrome biochem features?
hypoPO4 hypoCa hypoMg hyperK
73
hungry bone Tx?
Ca: 2-4g oral, IV if symptomatic or < 1.9
oral calcitriol 4mcg/day
avoid replacing PO4 unless extremely low < 0.32
74
hungry bone Px?
off paricalcitrol and cinacalcet and PO4 binder
Q8H CaPO4 Q8H checking
start caltrate 1.5g tds, Rocaltrol 0.5mcg bd
75
hypoCa sym?
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
hypoCa causes?
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
hypoCa Ix?
PTH low:
- low Mg: hypoMg
- normal Mg: hypoPTH
PTH high:
- PO4 high: CKD, PTH resistance
- PO4 low / N: Vit D deficiency
78
MEN1 / 2a / 2b features?
MEN1: pituitary adenoma, parathyroid hyperplasia, pancreatic tumor
MEN2a: parathyroid hyperplasia, medullary CA thyroid, phenochromocytoma
MEN2B: mucosal neuroma, marfanoid, medullary CA thyroid, pheochromocytoma
79
hypoCa Tx?
IV / PO Ca, Vit D
| thiazide if hypoPTH
80
hyperPO4 causes?
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
hypoPO4 causes?
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
PO4 reference range?
1-1.5mmol/L
83
hypoPO4 sym?
encephalopathy, hemolysis, thrombocytopenia, respi failure, rhabdomyolysis, cardiomyopathy
84
hypoPO4 Tx?
PO / IV replacement
85
hypoMg causes?
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
Anion Gap calculation?
Na - Cl - HCO3, cut off 12 +/- 2
| albumin adjust: adjusted AG = AG + (40 - alb) x 0.25
87
HAGMA causes?
ketoacid: DKA / AKA
lactic acidosis: L/D
Substance: methanol, ethylene glycol, panadol, salicylate
88
NAGMA causes?
GI cause: diarrhea, ureterosigmoidostomy
Renal cause: RTA1/2/4, CKD
Endocrine: hypoaldo
Drug: NSAID, acetazolamide
89
UAG calculation?
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
Diff RTA
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
causes of RTA2
```
MM, LCDD
hyperPTH
Drug: getamycin, TDF (tenovovir dixoproxil fumarate, avoid by tenovovir alafenamide fumarate)
Lead, cadmium, mercury
TIN: rejection, MCKD
```
92
RTA1 causes?
Autoimmune: Sjogren, PBC, SLE
Drug: amphoB, toluene
Nephrocalcinosis: hyperPTH, VitD
TIN: obstructive uropathy, transplant
93
lactic acidosis cause?
```
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
L vs D lactate?
D: SB resection / steatorrhea, causing bacterial overgrowth
| Tx by low carbo diet and antimicrobial
95
AKA diff DKA?
high B hydroxybutyrate to acetoacetate ratio
96
AKA Tx?
glucose infusion
97
Ethylene glycol and methanol sym?
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
ethylene glycol / methanol Tx?
fomepizole 15mg/kg IV loading then 10mg /kg Q12H then 15mg/kg Q12H after 48hr
IV ethanol 5/10% solution
HD
HCO3
99
OG calculation?
measured osmo - 2x Na + urea + glucose + (1.25 x Ethanol)
| high than 10 indicates toxic alcohol
100
metabolic alkalosis workup?
```
Chloride resistance: UCl > 30: aldo excess or aldosteroism, tubular problem (bartter, gitelman)
check renin / aldo
UCl < 10:
renal loss: diuretics
GI loss: vomiting
```
101
Winter formula
1.5 x HCO3 + 8 +/- 2
| mmHg to kPa: divided by 7.5
102
delta delta ratio
AG - 12 / 24 - HCO3
1 - 2: HAGMA
> 2: Mixed HAGMA + metabolic alkalosis: vomiting, diuretics
< 1: Mixed HAGMA + NAGMA: diarrhea
