Hyper & Hyponatraemia

Question 1

What categories can hypernatraemia be divided into?

Answer 1

hypovolaemic
euvolemic
hypervolemic

Question 2

What are the causes of hypovolaemic hypernatraemia?

Answer 2

• extra-renal cause
  
  • GI loss - vomiting, diarrhoea, fistula losses
  • dermal losses - burns/sweating
  • third space losses - ascites/peritonitis
• renal causes
  
  • diuretics
  • recovery from acute tubular necrosis

Question 3

What are the causes of euvolemic hypernatremia?

Answer 3

Water deficit with no change in intravascular volume

• extra-renal
  
  • dementia
  • imobilisation
• renal
  
  • diabetes insipidus - nephrogenic or craniogenic

Question 4

What are the causes of hypervolemic hypernatremia?

Answer 4

• extra-renal
  - iatrogenic
  - sea water
• renal causes
  
  • conn’s
  • cushing’s

Question 5

What are the symptoms of hypernatraemia?

Answer 5

• lethargy
• irritability
• thirst/dry membranes
• hyperreflexia
• muscle weakness
• seizures
• coma
• death

Question 6

Treatment?

Answer 6

replace fluid deficit

• aggressively in acute hypernatremia -hypotonic fluid or 5% dex
• slowly replace fluid in chronic hypernatremia

Question 7

other than U&Es what are tests are helpful in identifying the cause of hyponatraemia?

Answer 7

-serum and urine osmolality

Question 8

Causes of hypovolaemic hyponatraemia?

Answer 8

• diuretics
• addison’s
• diruetic stage of CKD

Question 9

Causes of euvolaemic hyponatraemia?

Answer 9

• SIADH
• hypothyroidism
• addison’s
• dilutional from too much H2O intake

Question 10

Sx of hyponatraemia?

Answer 10

vague stuff 
-fatgue
-headache 
-N&V
-dizziness 
-confusion 
-muscle cramps
(mild to moderate)

-seizure/coma/death = severe Na+ <120

Question 11

What is the treatment for hyponatraemia?

Answer 11

• fluid restriction - less than 800ml a day
• loop diuretics

If severe

• hypertonic saline over 3-4 hours
• then Tx as above