Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Path - Chempath > Sodium and Fluid balance > Flashcards

Sodium and Fluid balance Flashcards

(47 cards)

Start Studying
1
Q

What is normal range for Na?

A

135-145

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

What is hyponatraemia range?

A

Na <135

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

What is the pathogenesis of hyponatraemia?

A

The problem is not salt loss
It is EXCESS WATER compared go the salt
As such you must always treat for the excess water, not the salt

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

What hormone controls water balance in the kidneys?

A

ADH

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

What is the function of ADH

A

It promotes water retention by inserting Aquaporin 2 channels into the collecting duct cells

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

What are physiological triggers to ADH secretion?

A

high urine osmolality (salt)

low blood volume)

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

What is the first step in the management of hyponatraemic patients?

A

ASSESS VOLUME STATUS

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

What are clinical features of hypovolaemia?

A 
Tachycardia, postural hypotension 
Dry mucous membranes 
Reduced skin turgor 
Confusion, drowsiness
Reduced urine output 
Low urine Na
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What must you be aware of as urine findings if the patient is on diuretics?

A

They will have HIGH Na regardless

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

What are clinical features of hypervolaemia?

A

Raised JVP
Bibasal crackles
Peripheral oedema

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

What are causes of hypovolaemic hyponatraemia?

A

Diarrhoea, vomiting
Diuretics
Salt losing nephropahthy

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

How does hypovolaemic hyponatraemia occur?

A

With D&V > excess water loss > low perfusion pressure
This is detected by baroceptors > increase ADH production > increased water reabsorption
So more water is reabsorbed, and there is more water compared to salt

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

What are causes of euvolaemic hyponatraemia?

A

Hypothyroidism
Adrenal insufficiency
SIADH

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

How does hypothyroidism cause hyponatraemia?

A

Reduced cardiac congtractility > reduced BP detected by baroceptosr > more ADH > more water

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

What are causes of hypervolaemic hyponatraemia?

A

Cirrhosis
Cardiac failure
Renal failure

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

Summarise urinary sodium in the three hyponatraemias

A

Hypo/hypervolaemic: LOW

euvolaemic: high

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is SIADH

A

Syndrome of inappropriate ADH

caused by inappropriately released ADH e.g. CNS pathology, lung pathology,drugs, tumours, surgery,

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is plasma and urine osmolality in SIADH?

A

Plasma osmolality: low

Urine osmolality: HIGH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How do you treat hypovolaemic hyponatraemia?

Study These Flashcards
A

Volume replacement with 0.9% SODIUM CHLORIDE

20
Q

How do you treat euvolaemic hyponatraemia?

Study These Flashcards
A

Fluid restrict + treat underlying cause

21
Q

How do you treat hypervolaemic hyponatraemia?

Study These Flashcards
A

Fluid restrict + treat underlying cause

22
Q

What is clinical presentation of severe hyponatraemia’

Study These Flashcards
A

Reduced GCS
Seizures
Seek expert help (to treat with 3% hypertonic saline)

23
Q

What must you be aware of when correcting hyponatraemia?

Study These Flashcards
A

CENTRAL PONTINE MYELINOLYSIS

So do not correct serum sodium too rapidly

24
Q

what are symptoms of CENTRAL PONTINE MYELINOLYSIS

Study These Flashcards
A 
quadriplegia 
dysarthria
dysphagia 
seizures
coma 
death
25
What drugs do you use to treat SIADH, if fluid restriction is insufficient?
Demeclocycline | Tolvaptan
26
What serum level defines hypernatraemia?
Serum Na >145
27
What is hypernatraemia caused by?
Unreplaced water LOSS - should not happen as patient should feel thirsty and drink to compensate. So only occurs in elderly/fasting/can't keep up with losses - GI losses (nausea, vomiting) - Sweat losses - Renal losses (osmotic diuresis, diabetes insipidus, Conn's)
28
How do you treat hypernatraemia?
5% DEXTROSE (fluid replacement) | Treat underlying cause
29
How do you treat someone with hypovolaemic hypernatraemia?
0.9% saline (for hypovolaemia) | 5% dextrose (for hypernatraemia)
30
what is the difference between osmolaRity and osmolaLity
``` Osmolarity = calculated from blood test using FORMULA Osmolality = measurement of particles in solution, using MACHINE ```
31
What is the formula for osmolarity??
2(Na + K) + urea + glucose
32
what occurs in Gilbert's syndrome?
Reduction in UDP glucuronyl transferase activity to 30%
33
what occurs in Crigler Najjar syndrome?
Complete deficiency of UDP glucuronyl transferase
34
What are causes of SIADH
CNS pathology (/meningitis, encephalitis, absecess) Lung pathology (pneumonia, TB) Drugs (SSRI, TCA; opiate, PPI, carbamazepine) Tumour (non small cell lung cancer, breast cancxer) Surgery
35
What does Conn's do
Tumour causing excess production of Aldosterone > excess salt retention and K+ excretion also low renin levels (as it is suppressed by aldosterone)
36
How do you test for conn's
Aldosterone to renin ratio
37
How do you test for diabetes insipidus
water deprivation test | + add desmopressin
38
what must you look at to check if it is TRUE hyponatraemia
serum OSMOLALITY
39
What do high/normala/low serum osmolality indicate in the context of hyponatraemia?
High osmolality: glucose/mannitol infusion Normal osmolality: spurious, drip arm sample, pseudohyponatraeemia Low osmolality: true hyponatraemia
40
what electrolyte imbalance can occur following TURP^
HYPONATREMIA | from irrigation absorbed through the damaged prostatte
41
How do glucose/mannitol in blood cause hyponatraemia?
Glucose and mannitol are osmotically active they can draw water from the cells into the plasma this dilutes down the sodium
42
what are causes of hypontraemia post surgery?
overhydration with hypotonic IIV fluids | Transient increase in ADH due to stress of surgeyr
43
what are the different neurological impacts of HYPOnatraemia vs HYPERnatraemia rapid correction
HYPOnatraemia: cerebral pontine myelinolysis aka locked in syndrome HYPERNATRAEMIA: cerebral oedema
44
explain symptoms of diabetes insipidus
hypernatraemia (lethargy, thirst, irritaability, confusion, coma, fits) polyuria, polydipsia
45
what are causes of cranial diabetes insipidus
surgery, trauma, tumours LACK OF ADH
46
what are causes of nephrogeniuc diabetes insipidus
receptor defect (insensitivity to ADH) thiazide diuretic inherited channelopathies lithium, demeclocyclinee, hypercalcaemia
47
Explain T4 renal tubular acidosis
ALDOSTERONE DEFICIENCY/RESISTANCE causes acidosis and hyperkalaemia

Path - Chempath (23 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions