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Renal / Urology > Electrolyte Abnormalities + DI + SIADH > Flashcards

Electrolyte Abnormalities + DI + SIADH Flashcards

1
Q

What is K normally excreted for

A

Exchange for Na

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2
Q

What is a fatal level of K

A

> 7

Cause fatal arythmia - asystole / VF / cardiac arrest

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3
Q

What can cause hyperkalaemia

A

Decreased excretion
Increased K out of cells
Endocrine
Other

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4
Q

What causes decreased excretion

A 
Renal failure - AKI or CKD
ACEI / ARB 
NSAID
Heparin e.g. enoxoparin 
Spirnolactone (K sparing diuretic)
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5
Q

What causes increased K out of cells

A

Tumourlysis
Rhabdomyolysis
Metabolic acidosis - as K shifted out in exchange for H
BB - salbutamol used to treat

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6
Q

What are endocrine causes

A

Addison’s (hypo adrenal)

  • Increased K as decreased excretion
  • Low Na as decreased reabsorption
  • Low BP as low Na
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7
Q

What are other causes

A

Massive blood transfusion

Type 4 renal tubular acidosis seen with DM or CKD

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8
Q

What are symptoms of hyperkalaemia

A 
Weakness
Fast irregular pulse
Chest pain
SOB 
Paplitations
Dizzy
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9
Q

What do you need if symptomatic

A

U+E
ECG
Urgent dialysis / haemofiltration

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10
Q

How do you investigate

A 
DRABC
Stop all meds that cause 
Bloods - U+E 
ABG / VBG for K - repeat 
ECG for arrhythmia
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11
Q

What does ECG show

A 
Tall tented T waves
P wave widens
PR disappears
P wave disappears
Broad QRS
AV block 
Sinus brady or slow AF
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12
Q

What should you do if haemodynamically unstable

A

Dialysis

Haemofiltration

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13
Q

When do you treat urgently

A

K >6.5

ECG + K>6

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14
Q

How do you treat

A

Stop cause / drugs
Calcium gluconate / cholride
Insulin dextrose
Salubtamol

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15
Q

What dose calcium gluconate

A

10% 10 mls IV injection

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16
Q

What does it do

A

Stabilise myocardium if ECG changes

Gives 30-60 minute protection

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17
Q

What dose of insulin dextrose

A

50ml 50% 10 units insulin dextrose

Then infusion

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18
Q

What does it do

A

Shift K internally
Dextrose counteract sugar loss
Must monitor for hypo

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19
Q

What does of salbutamol

A

5-10mg neb
Tachy can limit use
Unlicensed

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20
Q

What can you use if K not that high

A

Calcium resonium

Used more in CKD to bring down over a few days

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21
Q

What do you do if this fails

A

Dialysis / anion exchange

Need to cure cause by getting patient to pee

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22
Q

Why are diuretics not really used

A

Cause hypovolaemia

DO NOT use unless overloaded as well

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23
Q

How do you prevent

A

Low K
Stop ARB / spironolactone
Treat cause

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24
Q

How do you treat renal tubular acidosis

A

HCO3

Flucotisone

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25
Q

What is emergency hypokalaemia

A

<2.5

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26
Q

What is most common causes of hypokalaemia (usually associated alkalosis as K is exchanged with H but can be due to acidosis)

A

D+V
Diuretic
Incorrect IV fluid replacement

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27
Q

What causes increased loss

A

Diuretic
D+V
Laxatives
Pyloric stenosis

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28
Q

What are endocrine causes

A

Cushing’s

Conn’s

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29
Q

What are other causes

A 
Alkalosis - K shifted in and H out 
Insulin / salbutamol excess
Steroid use
Type 1 and 2 renal tubular acidosis 
Tubular defect - Barter
Mg deficiency - must exclude and Rx 
Hypokalamic periodic paralysis
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30
Q

What are the symptoms of hypokalaemia

A 
Weakness
Hypotonia
Hyporeflexia
Cramps 
Tetany
Palpitations
Light headed
Constipation
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31
Q

What does hypokalaemia predispose you too

A

Digoxin toxicity

Careful if on diuretic

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32
Q

What does ECG show

A

U wave
Prolonged QT and PR
ST depression
Absent T

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33
Q

What will urine potassium show

A

If renal loss = high

If extra renal e.g. D+V then low

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34
Q

What should you do if renal loss

A

BP

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35
Q

If BP high

A 
Endocrine or renal artery stenosis 
Renin-angiotensin ratio
High in stenosis 
Normal in endocrine 
Measure cortisol / creatinine
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36
Q

If BP normal

A

Mg

HCO3 levels

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37
Q

Acidosis

A

Tubular acidosis

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38
Q

Alkalosis

A

Tubular defect

Diuretic

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39
Q

How do you treat

A 
Correct cause
Oral K if mild 
IV K if severe <2.5-3 or symptomatic 
e.g. 40mmol in 500ml saline x 2
If not that low then could give 40mmol in 1l bag
Monitor in cardiac area 
Consider K sparing diuretic
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40
Q

When would you not give K

A

If oliguric
Or as fast bolus - no more than >10mmol / hour
Try to dilute provided no CI e.g. HF

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41
Q

What is best indication of long standing K on diuretic

A

HCO3

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42
Q

What is most common cause of hypernatraemia

A

Water loss > Na loss
Dehydration
Fluid loss with no replacement - D+V / burns
Incorrect IV fluids

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43
Q

Other causes

A

DI - decreased ADH so increased water loss
Osmotic diuresis in diabetic coma
Conn’s - Primary aldosteronism as increased reabsorption

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44
Q

What are symptoms of hypernatraemia

A 
Lethargy
Thirst
Weakness
Irritable
Confusion
Coma
Seizure
Dehydration
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45
Q

What is important in bloods

A

Increased Na
Increased albumin
Increased urea suggestive of dehydration
Urine osmolarity

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46
Q

What else should you do

A

Water deficit calculator to work out

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47
Q

What wil dehydration have

A

High urine osmolality as trying to conserve water

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48
Q

What will DI have

A

Low osmolarity as no ADH so water just washed out

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49
Q

How do you treat hypernatraemia

A

Oral rehydration
Glucose 5% slow IV guided by output and plasma Na
0.9% saline if hypovolaemia

50
Q

What should you avoid

A

Hypertonic

51
Q

What do you need to do with regards to fluid and how fast do you go and why

A

Replace deficiency
Replace ongoing loss and insensible
Replace slowly no > than 0m5 as risk of cerebral oedema (seizure / coma / death)

52
Q

When would you suspect primary aldosteronism (Conn’s)

A

K down
BP up
Alkalosis

53
Q

What does dehydration always have

A

High Na

Not the same as hypovolemia

54
Q

What is most common

A

Hyponatraemia <130mmol

Either water excess or sodium depletion

55
Q

What is important with regards to hyponatraemia

A

FLUID STATUS
Doesn’t mean Na depletion
Can just be overloaded so dilutes

56
Q

What causes hypovolaemic (dehydrated) hyponatraemia

Urine Na >20

A 
Diuretic
Addison's 
Renal failure
Osmolar diuresis -hyperglycaemia
TURP Syndrome
57
Q

What causes hypovolaemic (Dehydrated) but urine Na <20 so lost other than kidney as kidney tried to hold on to Na / osmolarity high

A 
D+V
Fistula
Burn
Obstruction - 3rd space loss
Trauma
CF
Heat in extra sport = ongoing ADH release
58
Q

What can D+V cause

A

Low or high Na

59
Q

What drugs should you consider stopping / cause SIADH

A 
Diuretic
SSRI
PPI - omeprazole (beware with SSRI in elderly) 
TCA 
Sulphonamides 
Carbmazepine 
ACEI
60
Q

What causes hypervolaemic hyponatraemia - diltued NA

A 
Nephrotic
HF
Liver cirrhosis
Renal failure
Polydipsia
61
Q

What causes euvolaemic hypo

A

SIADH
Severe hypothyroid
Glucose-corticoid insufficiency

62
Q

What suggests SIADH

A

High urine osmolality and Na as less water excreted so concentrates
Think known cancer

63
Q

What are symptoms of hyponatrameia

A 
Confusion
Headache
ANorexia
Nausea
Malaise
Irritable
Weakness
CNS distubrance
Deceased CNS
Seizure
Encephalopathy
64
Q

What is a medical emergency

A

Rapid changes or acute

65
Q

How should you investigate

A

Fluid balance
Urine osmolarity
Serum osmolarity

66
Q

What are baseline bloods for cause

A 
Glucose
Lipids
TFT 
LFT 
-ve Short Synacthen for Addison 
Urine Na+K
67
Q

How do you test for Addison

A

Cortisol low

Short synapsin

68
Q

How do you treat hyponatraemia

A

Correct cause

Replace Na and water at same rate

69
Q

What do you do for asymptomatic and chronic

A

Fluid restrit
Loop diuretic
Can use
ADH antagonist or hypertonic but rare

70
Q

What do you do for acute severe symptomatic

A 
Cautious rehydration to correct cerebral oedema 
Hypertonic 3% saline or Hartman
150ml over 15 min
Repeat if no improvement
With or without ADH antagonist
Then determine fluid status
71
Q

What should you not do and why

A

Correct more than 10mmol/l in 24 hours

Risk of central pontine myelinolysis as pulls water from brain cells

72
Q

When would you consider furosemide

A

Not hypovolaemic

73
Q

If hypovolaemic

A

0.9% saline

74
Q

If hypervolaemic

A

Restrict
Treat cause- CF / liver /r renal
Have fluid intake < output if oedema / SIADH / renal failure

75
Q

What do you do if seizure or coma

A

Hypertonic (1.8%) saline + furosemide

Aim for gradual increase to 125

76
Q

What may happen if Na corrected rapid

A

HF
Central pontine myelinolysis / Osmotic demyelination syndrome
Correct no faster than 10mol in 24 hours

77
Q

What does ADH antagonist do (Tolvaptan)

A

Promote water excretion
No loss of electrolyte
Effectie if hypervolaemic or euvolaemic but expensive

78
Q

What can cause SIADH secretion

A 
Tumour - SCLC / pancreas / gut 
Empyema 
CF
Pneumonia / TB
Drugs - SSRI / TCA / carbamazepine / cyclophosphamide / thiazide / 
CNS - meningitis / encephalitis / abscess / haemorrhage / stroke 
Post-op major surgery
Head trauma
79
Q

How do you Dx

A 
Dx of exclusion as can't measure ADH
Exclude other causes of hyponatraemia
Assess fluid balance - euvolaemic 
Hypotonic hyponatraemia
Urine osmolarity high - high urine Na as concentrated 
CXR
CT head 
CAP 
Bronchoscopy
80
Q

What is Furst formula

A

Used to see if fluid restriction would be helpful in Rx

<1 = restrict

81
Q

What are other Rx for SIADH

A 
Fluid restrict
Demeclocycline - reduce responsiveness of collecting duct to ADH 
Tolvaptan
Correct Na - aim target 130
Diuretic
82
Q

What do you do if can’t tell if SIADH

A

Adminster normal saline 1l over 12 hours
Hypovolaemic responds
SIADH will not or may worsen

83
Q

What causes DI

A

Nephrogenic - insensitive to ADH

Cranial / central - deficient in ADH

84
Q

What causes nephrogenic

A 
Genetic = most common
Hypercalcaemia
Hypokalaemia
Drugs - lithium
Interstitial renal - pyelonephritis / sickle 
Chronic renal 
Post obstructive uropathy
85
Q

What causes cranial

A 
Idiopathic
Brain tumour 
Head injury
Pituitary tumour
Craniopharyngioma
Haemochromatosis / sarcoid 
Haemorrhoige 
Infection - meningoencephalitis
86
Q

What are the symptoms

A 
Polyuria
Polydipsia
As kidney's can't concentrate urine 
Nocturnal enuresis
Dehydration
Postural hypotension 
Symptoms of hypernatraemia
Due to impaired water resoprotion
87
Q

How do you Dx

A

High plasma osmolality
Low urine osmolality
Water deprivation test = test of choice
- Doesn’t affect urine osmolality as can’t concentrate
Can give synthetic ADH and see if respond
- Will respond in central but not nephrogenic
Do U+E, Ca, glucose to exclude DM
MRI if central
Exclude UTI

88
Q

How do you Rx

A

Thiazide if nephrogenic - release more Na to lower plasma osmolality
Low salt
Low protein
Desmopression if central - synthetic ADH

89
Q

What are more common causes of polyuria

A 
Diuretic
Caffeien
Alcohol
DM
Lithium
HF
Hypercalcaemia
Hyperthyroid
90
Q

How does metabolic acidosis cause hyperkalaemia

A

K and H ions fight to be exchanged for Na in distal tubule

91
Q

What is hypokalaemia associated with

A

Alkalosis
As K is taken into cells and H released
So K loss

92
Q

What can hypo be associated with

A

Acidosis e.g. renal tubular

93
Q

Symptoms of osmotic demyelination syndrome / central pontine demyelinolysis

A 
Confusion, headache, N+V
Dysthria
Dysphagia
Paresis
Seizure
Coma
94
Q

When should fluid intake be less than output in treatment of hyponatraemia

A

Oedematous states
SIADH
Renal failure
Psychogenic polydipsia

95
Q

Why should you replace fluid slowly in hypernatramia

A

Risk of cerebral oedema (seizure / coma) as brain loses electrolytes quickly whilst lowering of other electrolytes and water occurs more slowly

96
Q

What causes hypo phosphate

A 
Alcohl
Acute liver failure
DKA
Refeeding
Primary hyperparathyroid
Osteomalacia
97
Q

What are the consequences of hypophosphate

A 
RBC haemolysis
WBC / platelet dysfunction
Muscle weakness
Rhabdomyolysis
CNS dysfunction
98
Q

What causes raised ALP physiological

A

Growing child
Pregnancy
Heeling fracture

99
Q

What causes pathological raised

A 
Liver 
Osteomalcia
Bone mets
Pagets
Renal failure
Hyperparathyroid
100
Q

What causes high Ca

A

Bone mets

Hyperparathyroid

101
Q

What causes with low Ca

A

Osteomalacia

Renal failure

102
Q

What are causes of hypocalcaemia

A 
Vit D deficiency (osteomalacia) 
CKD 
Renal failure
Hypoparathyroid (surgery / thyroiditis)
Pseudohypoparathyroid (insensitive) 
Rehabdomyolysis
Mg deficiency 
Massive blood transfusion
Acute pancreatitis
103
Q

What is calcium needed for

A

Muscle and nerve function

104
Q

What does hypo cause

A 
Tetany
Parathesia 
Increased QT
Trosseau
Chvostek's
105
Q

What is tetany

A

Twitching
Cramping
Spasm

106
Q

If chronic

A

Depressoion

Cataracts

107
Q

What is trousseau

A

Carpal spasm when brachial artery occluded when BP cuff above systolic
Wrist flexion and fingers drawn in

108
Q

What is Chvostek

A

Tapping paranoid causes facial muscles to twitch

109
Q

How do you treat hypocalcaemia

A

IV calcium gluconate 10ml 10% 10 minutes if severe
ECG
Treat cause

110
Q

How do you treat hypercalcaemia

A

Rehydration
Normal saline
3-4l per day

111
Q

What can be used after

A

Biphosphonates

Calcitonin - works quicker

112
Q

What do you give if caused by sarcoid

A

Steroids

113
Q

What can be used but careful

A

Loop diuretics if can’t tolerate fluid but may worsen other electrolyte imbalances

114
Q

What advise do you give

A

Advise good hydration

Avoid drugs that will worsen hypercalcameia

115
Q

If correct hypernatraemia too fast

A

Cerebral oedema

116
Q

If correct hyponatrameia too fast

A

Central pontine demyelinisys /

117
Q

Causes of hypomagnesium

A 
Diuretic 
PPI 
TPN
Diarrhoea
Chrons / UC
Hypo K 
Hypo Ca due to reduced PTH 
Metabolic - Gilberts
118
Q

Sx

A

ECG similar to hyperkalaemia
Symptoms same as hypo calcium
Exacerbates digoxin toxicity

119
Q

Rx

A

Replace

120
Q

If low phosphate

A

Add polyfuser

Renal / Urology (16 decks)

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