Common Electrolyte Abnormalities in Emergency Medicine

1. COMMON ELECTROLYTE
ABNORMALITIES IN EMERGENCY
MEDICINE
Tim Martin Dec 2016

2. AIMS AND OBJECTIVES
To discuss the investigation and diagnosis of common
electrolyte abnormalities
Specifically focusing on hyponatraemia and a way to
subdivide causes
To become familiar with emergency management of these
conditions

3. SODIUM
Main extracellular electrolyte
Distributed in the extracellular fluid which accounts for 20% total
body weight and 33% total body water
Sodium concentrations mEq/L:
• Plasma 142
• Normal saline 154
• Hartmann’s 130

4. HYPONATRAEMIA
Serum sodium below 130mEq/L
Moderate symptoms < 130 : Headache, confusion, agitation
Severe symptoms < 120 : Intractable seizures, vomiting,
coma
Mortality due to cerebral oedema and brainstem herniation

5. ASSESSMENT
Clinical fluid status
Urine and plasma osmolality
Calculated osmolality = 2 x (Na + K) + Glucose + Urea
Urine sodium

6. 61 year old male referred in
from GP with Sodium 121 on
routine blood tests
Repeat blood checked -
sample as shown
What specific management
does this patient require?

7. PSEUDOHYPONATRAEMIA
Occurs with severe hyperproteinaemia or hyperlipidaemia
Analytical error due to water displacement in sample
Some laboratories may be able to correct value
No treatment required for sodium, GP to review lipid profile
please!

8. HYPEROSMOLAR
HYPONATRAEMIA - >295
Similar phenomenon with hyperglycaemia
Corrected Sodium = Sodium + (Glucose - 5)/4
Hyponatraemia occurs due to osmotic diuresis including
mannitol use
Correct with saline

9. HYPO-OSMOLAR
HYPONATRAEMIA < 275
Hypovolaemic
Normovolaemic
Hypervolaemic

10. Hypovolaemic hyponatraemia - Loosing sodium in excess to wate
PRE RENAL RENAL LOSS
Third space loss
Sweating/vomiting/diarrhoea
Addison’s
Diuretic phase of renal failure
Renal tubular acidosis
Thiazide diuretics

11. Normovolaemic hyponatraemia
URINE OSMOLALITY < SERUM OSMOLALITY URINE OSMOLALITY > SERUM OSMOLALITY
Tea and toast diet
Psychogenic polydipsia
Iatrogenic
Amphetamine use
Exercise induced - hypotonic fluid
ingestion
SIADH

12. SYNDROME OF
INAPPROPRIATE ADH
SECRETION
Precipitated by malignancy (ectopic ADH in small cell lung cancer),
head injury/intracerebral infection, medications (cyclophosphamide,
carbamazepine, SSRIs, amiodarone)
Hypotonic hyponatraemia
Urine osmolality > serum osmolality
Urine Sodium > 20mmol
Euvolaemia clinically
Normal adrenal, renal, cardiac, hepatic and thyroid function

13. Treatment includes:
Fluid restriction
Vasopressin antagonists eg tolvaptan
Demeclocycline and lithium

14. Hypervolaemic - Oedematous state
Congestive cardiac failure, liver cirrhosis, nephrotic
syndrome
Treated with fluid restriction
In CCF consideration loop diuresis and or vasopressin
antagonist eg tolvaptan

15. EMERGENCY MANAGEMENT
HYPONATRAEMIA - SEIZURES
Target a sodium of 125
3ml/kg of 3% sodium chloride will raise sodium by 3
OR
100ml 3% sodium chloride over 10-15 minutes repeated
unto a total of 300ml based on clinical symptoms
Limit sodium increase to 8mEq/L in first 24 hours

16. 3 days post admission for hyponatraemia, corrected with
hypertonic saline in intensive care patient stepped down to
ward
Over next day develops dysarthria, dysphagia and a bulbar
palsy
What complication has occurred?

17. 2 weeks post total
thyroidectomy a 60 year old
man presents with cramping in
hands and feet
Surgical note state 2
parathyroid glands spared
When blood pressure checked
his left wrist painfully contracts
What is the most likely
underlying problem?
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc

18. HYPOCALCAEMIA
Ionised calcium less than < 2
Most body calcium bound in bone
Ionised calcium (50%) is the active form compared with protein
bound (40%) and complex calcium (10%)
PTH secreted in response to hypoclacaemia and is influenced by
vitamin D and magnesium
PTH increases osteoclast activity as well as inducing calcium
reabsorption in the kidney and vitamin D synthesis

19. CLINICAL SIGNS AND
COMPLICATIONS
Chvostek sign and Trousseau sign
https://www.youtube.com/watch?v=6jFwxawwcbg
https://www.youtube.com/watch?v=2quH8gvtEAw
Spasms and cramps
Arrhythmias and Torsade de Pointes
Hallucinations and seizures

20. INVESTIGATIONS
Total and ionised calcium, PTH level, Vitamin D,
Magnesium, Albumin level, Renal function and electrolytes
ECG - prolonged QTc, T wave changes resembling
ischaemia

21. TREATMENT
Oral replacement 500 - 3000mg elemental calcium/day
IV calcium chloride (10ml of 10%) vs calcium gluconate (10-
30ml of 10%)
Caution if concurrent digoxin use

22. 75 year old lady presents short
of breath
?COPD, crackles all over
chest
? Ischaemic ECG

23. VBG shows a new creatinine of 750 and a potassium of 7.9

24. MANAGEMENT OF
HYPERKALAEMIA
Cessation of nephrotoxic agents and potassium sparing
diuretics
Enhanced elimination - fluids, diuretics, binding agents,
dialysis
Membrane stabilisation with constant ECG monitoring -
Calcium (gluconate vs chloride again)
Moving potassium intracellularly - Salbutamol nebulisers, 10
units ActRapid insulin in 50mls 50% dextrose, Sodium
bicarbonate (if patient acidotic)

25. Tintinalli’s Emergency Medicine 8th edition. Tintinalli et al
Oxford Handbook Emergency Medicine 7th edition.
Longmore et al
Textbook of Adult Emergency Medicine 4th edition.
Cameron et al
Life in the Fast Lane