Electrolyte Imbalances Flashcards

1
Q

Hyperkalaemia

A

high serum K+

main complication is cardiac arrhythmias such as ventricular fibrillation

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2
Q

causes of hyperkalaemia

A
Acute kidney injury
Chronic kidney disease
Rhabdomyolysis
Adrenal insufficiency
Tumour lysis syndrome
Aldosterone antagonists (spironolactone and eplerenone)
ACE inhibitors
Angiotensin II receptor blockers
NSAIDs
Potassium supplements
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3
Q

investigations for K+

A

U&E’s
Creatinine, Urea, eGFR

Haemolysis (break down of RBC) can cause a falsely elevated potassium

ECG
tall tented T waves
flattening / absence of p waves
broad QRS complex

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4
Q

treatment of hyperkalaemia

A

insulin (actrapid 10 units) and dextrose infusion (50mls of 50%)
IV calcium gluconate

insulin and dextrose drives carbohydrates into the cells and will take K+ with them (which will reduce the blood potassium)

calcium gluconate- stabilises the cardiac muscle. reduces the risk of arrhythmia

alternative:
Nebulised salbutamol temporarily drives potassium into cells.
IV fluids can be used to increase urine output, which encourages potassium loss from the kidneys (but don’t fluid overload patients with renal failure).
Oral calcium resonium draws potassium out of the gut and into the stools. It works slowly and is suitable for milder cases of hyperkalaemia.
Sodium bicarbonate (IV or oral) may be considered on the advice of a renal specialist in acidotic patients with renal failure. It drives potassium into cells as the acidosis is corrected.
Dialysis may be required in severe or persistent cases associated with renal failure.
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5
Q

when do you need to treat hyperkalaemia?

A

<6mmol/L but otherwise stable renal function= do not need urgent tx, require a chnage in diet / meds

> 6mmol/L and ECG changes need urgent tx

> 6.6mmol/L and regardless of ECG need urgent tx

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6
Q

Hypernatraemia causes and symptoms

A

sodium >155mol/L

conn's
cushing's 
dehydration
diabetes insipidus (cranial / nephrogenic)
iatrogenic

symptoms:
thirst, drowsy, dehydrated, agitated, confusion

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7
Q

hypernatraemia treatment

A

rehydrate with IV fluids- Hartmann’s (avoid saline)

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8
Q

Hyponatramia causes

A

SIADH
<130-135
125-130
<125 (severe, seizure)

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9
Q

types of hyponatraemia

A

hypovolemic hyponatraemia: dehydration, diuretics, GI losses (fluid status)

hypervolemic hyponatraemia (dilutional)
too much ADH / vasopressors
heart / kidney / liver failure
(this dilutes the sodium)

give diuretics to get rid of the fluid but be cautious to not cause hypovolemia. loop diuretics.

euvolemic hyponatraemia
SIADH
mainly drug related (ACEi, ARB)
early addisons
hypothyroidism
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10
Q

hyponatraemia symptoms

A
sunken eyes
dry mucus membrans
hypotension
low urine output
capillary refill >3s
thirsty
skin turogr
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11
Q

hyperkalaemia

A

K+ >5.5mmol/L
risk of arrhythmias (ECG- tall tented T waves)

can be due to inadequate excretion

  • potassium sparing (spironolactone)
  • chronic renal failure
  • ACEi, losartan= reduce K+ excretedon

or addition of K+

  • diet
  • meds
  • iatrogenic fluids

symptoms:
usually an incidental finding

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12
Q

hyperkalaemia treatment

A

calcium gluconate and insulin
*this stabilises the heart membrane (cardio protective)
10mls of 10% calcium glucagon over 10 mins

insulin transports the K+ back into the cells
(actrapid)

10% dextrose in 500mls to prevent a drop in blood sugar levels

*can give salbutamol nebuliser whilst preparing

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13
Q

hypokalaemia

A

medication = loose K+
diuretics, loop diuretics, diarrhoea, vomiting
cushing’s disease
conn’s
refeeding syndrome (starvation- body has adapted to anabolic and now fed= catabolic and uses up a lot of electrolytes)

causes:

  • Barters?
  • Gittlemen? thiazie
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14
Q

hypokalaemia

A
K+ supplementation
SenoKay KCl (IV replacement)
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15
Q

hypomagnesaemia

A

can cause arrhythmias
check K+, ca2+ aswell
severe hypomagnesemia can cause long QT (torsades de points)

causes:
D and V
malnourishment
alcohol
anorexia
renal tubular acidosis
PPI's

treatment: shock - treat like VF then give IV Mg2+

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16
Q

hypocalcaemia

A

long QT
arrhythmias- bradyarrhythmias

causes:
GI losses
diuretics
vitamin D deficiency

17
Q

hypercalcaemia

A
hyperparathyroidism
boney metastasis
osteolytic lesions
paraneoplastic phenomenon
excess vitamin D
CKD
multiple myeloma
symptoms:
confused/agitated
bone pain
abdominal pain
pancreatitis
psychotic changes
'bones growns stones'
18
Q

hyperparathyroidism

A

type 1: tumor= parathyroid hyperplasia
PTH high, ca2+ high

type 2: PTH high, low ca2+ stimulates more PTH to be produced (too much) = renal disease

type 3: long term hypocalcaemia causes hyperplasia fof PTH= PTH high, ca2+ low/normal

19
Q

treatment of hypercalcaemia

A

rehydration
3L in first 24 hours
If ca2+ <3 no need to

if >3 give bisphosphonates after (pemidronate, zolandronic acid)

if no malignancy give

20
Q

SIADH

A

posterior pituitary land
aquaporin
chest infection, atypical pneumonia, cancer (small cell) head injury, brain tumor, stress response post surgery.

meds: anti epileptics, antipsychotics, SSRI
star SSRI- drop Na+?
SIADH: fluid restirction 1.5?????

21
Q

hyponatraemia treatment

A

restricted fluid intake
reverse any dilution
treat the underlying cause

administer saline if restriction fails

treating hyponatraemia too fast can precipitate central pontine myelinolysis

22
Q

malignant hyperkalaemia

A

oncological and palliative care emerngecy

> 2.8mmol/L

treat with 2L of 0.9% sodium chloride over 24 hours. (rehydration)

followed by bisphosphonate infusion

23
Q

thiamine deficiency

A

(wenricke’s encephalopathy)
nystagus and ataxic gait
IV thiamine
Ct scan to rule out other cause

24
Q

digoxin OD

A

management- DigiFab (digoxin immune Fab)

25
Q

cyanide posioning

A

sodium thiosulface- a sulfur donor that allows enzymes involved in cellular respiration to function again