[6] Hypernatraemia Flashcards

1
Q

Is hypernatraemia common?

A

No, it is a relatively rare presentation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is hypernatraemia defined as?

A

Serum sodium concentration over 145mmol/L

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

When are symptoms seen in hypernatraemia?

A

When serum sodium is >160mmol/L

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the causes of hypernatraemia divided on the basis of?

A

Fluid volume status

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the causes of hypovolaemic hypernatraemia?

A
  • Diuretics
  • Dehydration
  • Acute tubular necrosis
  • Hyperosmolar states
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Which is the main diuretic that causes hypernatraemia?

A

Loop diuretics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Give 5 examples of things that can cause dehydration

A
  • Fluid restriction
  • Diarrhoea
  • Vomiting
  • Burns
  • Excessive sweating
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the causes of euvolaemic hypernatraemia?

A

Diabetes insipidus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the causes of hypervolaemic hypernatraemia?

A
  • Excessive hypertonic saline administration
  • Steroid excess
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Give two examples of causes of steroid excess

A
  • Conn’s syndrome
  • Cushing’s syndrome
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is true of the symptoms of hypernatraemia?

A

Hypernatraemia is generall asymptomatic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What can mild cases of hypernatraemia result in?

A

Excessive thirst

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the symptoms of more severe cases of hypernatraemia?

A
  • Weakness
  • Lethargy
  • Irritability
  • Confusion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What can happen in cases where sodiun concentration is >200?

A

Neurological deficits can appear, including;

  • Ataxia
  • Tremor
  • Coma
  • Seizures
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What investigations are done in hypernatraemia?

A
  • Metabolic panel of bloods
  • Blood gas
  • Urine osmolality
  • Further investigations depending on underlying cause
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is looked at in the metabolic panel of bloods in hypernatraemia?

A

Serum sodium, glucose, potassium, chloride, urea, and creatinine

17
Q

What further investigations may be done in hypernatraemia depending on suspected underlying cause?

A
  • ADH levels
  • CT head
18
Q

As a general rule, what do sodium levels of 150-170mmol/L usually indicate as a cause?

A

Volume depletion

19
Q

As a general rule, what do sodium levels of >170mmol/L usually indicate as a cause?

A

Diabetes insipidus

20
Q

As a general rule, what do sodium levels of >190mmol/L usually indicate as a cause?

A

Exogenous sodium gain

21
Q

What causes of hypernatraemia is hypertonic urine seen with?

A

Extra-renal fluid

22
Q

What causes of hypernatraemia is isotonic urine seen with?

A
  • Diuretic use
  • Osmotic diuresis
  • Salt wasting
23
Q

What causes of hypernatraemia is hypotonic urine associated with?

A

Polyuria from diabetes insipidus

24
Q

What laboratory signs may accompany hypernatraemia?

A
  • Increased PCV
  • Increased albumin
  • Increased urea
25
Q

What is the aim of the management of hypernatraemia?

A

To replace any fluid deficit, and correct serum sodium at a suitable rate

26
Q

What does the means by which hypernatraemia is managed depend on?

A

The underlying cause

27
Q

Why is it important not to correct serum sodium too rapidly in hypernatraemia?

A

Due to the risk of cerebral oedema

28
Q

How fast should you aim to lower serum sodium in hypernatraemia?

A

By 10mmol/L/day

29
Q

How is any fluid deficit replaced in hypernatraemia?

A

Enteric water replacement is preferred when possible, including administration via a nasogastric tube if possible. If enteric intake not possible, IV

30
Q

What is the IV fluid of choice in hypernatraemia?

A
  • 5% dextrose
  • 0.9% saline if evidence of volume depletion
  • 0.45% saline or Hartmann’s solution
31
Q

What should rates and fluid composition of IV fluid be adjusted depending on in fluid replacement in hypernatraemia?

A
  • Sodium levels
  • Fluid status