SIADH Flashcards

1
Q

define SIADH?

A

characterised by continued secretion of ADH, characterised by hyponatraemia secondary to the dilutional effects of excessive water retention

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

what are causes of SIADH?

A
Malignancy	
•	small cell lung cancer
•	also: pancreas, prostate
Neurological
•	stroke
•	subarachnoid haemorrhage
•	subdural haemorrhage
•     meningitis/encephalitis/abscess
Infections
•	tuberculosis
•	pneumonia
Drugs	
•	sulfonylureas*
•	SSRIs, tricyclics
•	carbamazepine
•	vincristine
•	cyclophosphamide
Other causes	
•	positive end-expiratory pressure (PEEP)
•	porphyrias
•	alcohol withdrawl
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

summarise the epidemiology of SIADH?

A

• Hyponatraemia is the MOST COMMON electrolyte imbalance seen in hospital

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

what are the presenting symptoms of SIADH?

A
  • Mild hyponatraemia may be ASYMPTOMATIC
  • Headache
  • Nausea/vomiting
  • Muscle cramp/weakness
  • Irritability
  • Confusion
  • Drowsiness
  • Convulsions
  • Coma
  • Symptoms of underlying cause
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

signs of SIADH on physical examination?

A

• MILD hyponatraemia - no signs
• SEVERE hyponatraemia:
o Reduced reflexes
o Extensor plantar reflexes

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

what investigations should be undertaken for SIADH?

A

o Low serum sodium
o Creatinine (check renal function)
o Glucose, serum protein and lipids

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

what is pseudohyponatraemia?

A

when the sodium concentration is actually normal but is erroneously reported as being low because of the presence of either hyperlipidaemia or hyperproteinaemia

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

what investigation results will confirm SIADH?

A

o Low plasma osmolality
o Low serum Na+ concentration
o High urine osmolality
o High urine Na+

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

management plan for SIADH?

A
  • Fluid restriction
  • Vasopressin receptor antagonists
  • In SEVERE cases - slow IV hypertonic saline and furosemide with close monitoring
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

when does central pontine myelinolysis occur ?

A

occurs with rapid correction of hyponatraemia

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

what is central pontine myelinolysis characterised by?

A
  • Quadriparesis
  • Respiratory arrest
  • Fits
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

prognosis for SIADH?

A
  • Depends on the CAUSE
  • Na+< 110 mmol/L is associated with a HIGH MORBIDITY and MORTALITY
  • 50% mortality with central pontine myelinolysis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly