Hyponatremia

Question 1

What is the safe limit for rising sodium in hyponatremia

Answer 1

8-10mmol/L in 24 hours

Question 2

Definition of hyponatremai

Answer 2

<135 mmol/L Na

Question 3

What conditions is hyponatremia ass with

Answer 3

Heart disease
Liver cirrhosis
Neurological disorders

Question 4

Grading of hyponatremia levels

Answer 4

• Mild - 130-135
• Moderate - 125-129
• Profound <125

Question 5

Symptoms of hyponatremia

Answer 5

Asymtpomatic
Headache
N+V
Muscle cramps
Lethargy

Question 6

Signs of hyponatremia

Answer 6

Disorientation
- Seizures
- Coma
- Cerebral oedema
- Death

Question 7

What base management of hypoNa off

Answer 7

Clinical presentation AND levels

Question 8

Causes of hyponatremia

Answer 8

Reduced renal free water clearance
Pseudohyponatremia - hypertriglyceridaemia
Sodium depletion
Excess water intake
SIADH

Question 9

Reduced clearance free water -> hyponatremia causes

Answer 9

• Hypovolaemia
  
  • Drugs
  • Renal failure
  • Portal hypotension and ascites
  • Hypoabuminaemia
  • Sespsis and vascular leak
  • Central salt wasting
  • Fluid sequestration
• Cardiac failure
• Nephrotic syndrome
• Hypothyroidism
• SIADH, nephrogenic SIADH
• Hypoadrenalism

Question 10

Sodium depletion causes

Answer 10

• Renal loss
  
  • Diuretics
  • Salt wasting/ central SW
  • Nephropathy
  • Hypoaldrenalism
• Extra renal loss - Gut los

Question 11

Excess water intake -> hyponatremia causes

Answer 11

• Dipsogenic DI
• Sodium free hypo-osmolality IV solutuons
• Dilute infant feeding formulas
• IV therapy

Question 12

Essentuak criteria for SIADH

Answer 12

Hyponatremia
Clinical euvolaemia
Serum osmolality <275 Osm/kg
Urine osmol >100mOsm/kg
Urina Na .30mmol/L
RULE OUT - see card

Question 13

What need to rule out in diagnosing SIADH

Answer 13

No recent diuretic
Absence of:
Hyotension, hypovolaemia
Non osmotic AVP release
Oedema
Adrenal, thyroid and renal insufficiency

Question 14

Why is SIADH diangosis of exclusion

Answer 14

Because management is fluid restricition which is opposite treatment to most other causes of hyponatremia

Question 15

Drugs that cause SIADH

Answer 15

• SSRI
• Carbamazepine
• Phenothiazines
• TCAs
• Cyclophophamide
• Opiates
• Vincristine
• NSAIDs
• Clofibrate
• PPIs

Question 16

CNS causes of SIADH

Answer 16

Inflammatory
Tumour
Infection

Question 17

SIADH causes - chest

Answer 17

Infection
Structural
Inflammatory eg sarcoidosis
Small lung cell carcinoma

Question 18

Bedisde investigations for SIADH

Answer 18

Urine investigations - sodium and osmolality
Plasma
Osmolality
LFTs, bone panel
TFTs
9am cortisol

Question 19

Radiology for SIADH

Answer 19

• CXR
• Consider CT chest, abdo , pelvis if SIADH confirmed and no cause identified

Question 20

What can cause non hypotonc hyponatremia

Answer 20

Hyperglycaemia

Question 21

Causes of urine osmolality ,100mOsmol/kg

Answer 21

• Primary polydipsia
• Inappropriate IV fluids
• Low solute intake eg
  
  • beer potamania syndrome - high volumes of beer (low solute) → hyponatremia

Question 22

Causes of hyponatremia where serum .100mOsmol/kg but urine <30mmol/L

Answer 22

• Low effective atrial volume HF
• Cirrhosis/portal HPTN
• Nephrotic syndrome
• Hypoalbuminaemia
• Third space loss
• GI loss
• Prev diuretic use

Question 23

Causes of hyponatremia where serum .100mOsmol/kg but urine >30mmol/L

Answer 23

Diuretics or ACE

Question 24

Mangement hyponatremia

Answer 24

Exclude hyperglycaemia
Treat w hypertonic saline if any severe symptoms over 20 mins Otherwise stop non essential pareneteral fluids + meds ass w hyponatremia + treat underlying cause
If clinically well dont try and correct sodium levels

Question 25

Severe symptoms of hyponatremia

Answer 25

Coma, seizure

Question 26

What happens in overrapid collection of hyponatremia?

Answer 26

Osmotic demyelination sydnomre

Question 27

What does osmotic demyelination syndrome cause

Answer 27

Quadriplegia Opthalmoplegia Psuedobulbar pasly Coma Death