Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Y6 Revision > Electrolyte abnormalities > Flashcards

Electrolyte abnormalities Flashcards

1
Q

What are the hypovolaemic causes of hypernatraemia

A

Increased sodium
- Medical high intake: hypertonic saline, sodium bicarbonate
- Dietary intake
- Conn’s syndrome/Cushing’s syndrome
- Renal artery stenosis

Loss of water
- Sweat and GI loss
- Renal loss: osmotic diuresis
- Diabetes insipidus

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

What investigations should be done for hypernatraemia

A

Urine dip

Glucose: ?DM
U&Es: ?hypokalaemia (n-DI)
Bone profile: ?hypercalcaemia (n-DI)

Plasma and urnie osmolality: ?Hyperaldosteronism (High pOsm, low uOsm)
Water deprivation testing

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

Management for hyponatraemia

A

Correct water deficit with 5% dextrose
Correct ECF volume depletion with 0.9% saline
Serial Na+ measurements every 4-6 hours

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

What are the complications of sodium level correction

A

Rapid hypernatraemia correction → cerebral oedema
Rapid hyponatraemia correction → central pontine myelinolysis

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

What would a water deprivation test show normally

A

0h pOsm: normal
8h uOsm: >600
DDAVP uOsm: >600

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What would a water deprivation test show in psychogenic polydipsia

A

0h pOsm: low
8h uOsm:>400 (>800 = diagnostic)
DDAVP uOsm: >400

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

What would a water deprivation test show in cranial DI

A

0h pOsm: high
8h uOsm: low
DDAVP uOsm: > 600

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What would a water deprivation test show in nephrogenic DI

A

0h pOsm: high
8h uOsm: low
DDAVP uOsm: <300

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

What is the initial assessment for a patient who is hyponatraemic

A

Assessment of serum osmolality - is it true hyponatraemia?

Clinical assessment of volume status (hypo-, euvo-, or hypervolaemic)

  • Check pulse
  • JVP
  • BP
  • Skin turgor
  • Signs of oedema
  • Mental state
  • Urine output

+ Urine electrolytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the causes of hypovolaemic hyponatraemia

A

Anything that causes loss of both water and sodium
urine Na >20: renal causes
Diuretics
Salt-losing nephropathy
Addison’s

urine Na <20: non-renal
Diarrhoea and vomiting
Excess sweating
Third space loss (ascites, burns, sepsis, pancreatitis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the clinical signs of hypovolaemia

A

Tachycardia
Postural hypotension
Dry mucous membranes
Reduced skin turgor
Confusion/drowsiness
Reduced urine output

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

What are the causes of euvolaemic hyponatraemia

A

SIADH (AQA2 insertion → water retention → increased volume → RAAS suppression → less aldosterone → reduced Na absorption
Hypothyroidism (→ reduced contractility → reduced BP → ADH release)
Adrenal insufficiency (→ less aldosterone → less Na+ reabsorption)

Urine sodium always >20. If <20 → consider potomania (no salt due to malnutrition)

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

What are the causes of SIADH

A

CNS pathology – stroke, haemorrhage, tumour
Lung pathology – small cell lung cancer, pneumonia (Legionella), pneumothorax
Drugs – SSRI, TCA, PPI, carbamazepine, opiates
Tumours - small cell, pancreas, prostate, lymphoma
Surgery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What investigations should be ordered in someone with euvolaemic hyponatraemia

A

Hypothyroidism → thyroid function tests
Adrenal insufficiency → short SynACTHen test
SIADH → plasma and urine osmolality → low plasma and high urine osmolality

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How is SIADH diagnosed

A

True hyponatraemia <135
Reduced plasma osmolality (resorbing lots of water) <270
Increased urine osmolality >100
High urine sodium >20
No hypovolaemia (euvolaemia)
No hypothyroidism
No adrenal insufficiency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the causes of hypervolaemic hyponatraemia

A

Urine Na >20: renal
AKI
CKD
Renal failure → not excreting enough water, not retaining sodium

Urine Na <20: non-renal
Cardiac failure (infective endocarditis)
Cirrhosis (glomerulonephritis, hep C)

17
Q

What is the management for hypovolaemic hyponatraemia

A

Volume replacement with 0.9% saline - SLOWLY and check Na regularly
Treat the underlying cause

18
Q

What is the management for hypervolaemic hyponatraemia

A

Fluid restriction (<750ml/day)
Treat underlying cause
Consider loop diuretic (rid of volume)

19
Q

What can cause a false hyponatraemia

A

Pseudohyponatraemia: raised triglycerides
Raised glucose
Pararotein (turbid)
Spurious sample

20
Q

What is the management for euvolaemic hyponatraemia

A
  1. Stop drugs
  2. Fluid restriction (1L/day)
  3. consider hypertonic saline
  4. Consider tolvaptans

Very ill → diuretics

21
Q

What are the causes of post-op hyponatraemia

A

Stress/pain/opioids → ADH release
Hypovolaemia
Sepsis

Y6 Revision (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions