Hyponatremia resident survival guide

Jump to navigation Jump to search

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Definition

Causes

Life Threatening Causes

Conditions that may cause death or permanent disability within the next 24 hours

Common Causes

Management

 
 
 
 
 
 
 
 
 
 
Serum sodium < 135 mEq/L
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Plasma osmolality
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Hypotonic < 280
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Isotonic/Hypertonic
(Pseudohyponatremia) > 280
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Assess volume status
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Increase in osmotically active
compounds; glucose, protein, lipid,
mannitol, sorbitol
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Hypovolemia
 
Hypervolemia
 
 
 
Euvolemia
 
 
 
 
 
 
 
Treat etiology
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Spot urine Na < 10,
BUN/Creatinine > 20:1,
Urine osmolality > 450
 
Same as hypovolemia,
Spot urine Na < 10,
BUN/Creatinine > 20:1,
Urine osmolality > 450
 
 
 
Spot urine Na > 20,
BUN/Creatinine < 20:1,
Urine osmolality > 300
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
GI, renal losses,
dehydration, diuretics,
adrenal insufficiency,
cerebral salt wasting
syndrome
 
heart failure
cirrhosis
renal failure
 
Urine osmolality > 300
 
Urine osmolality 50-100
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
(a) Normal saline;
(b) If neurological
sign/symptoms 3%
hypertonic saline,
and furosemide
 
Fluid restriction,
Diuretics,
Treat etiology
 
SIADH, Hypothyroidism
 
Compulsive water drinking
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
(a) Fluid restriction
(b) Demeclocycline (if
fluid restriction fails)
(c) Vaptans; Conivaptan,
Tolvaptan for resistant cases
 
Treat etiology
 
 
 
 
 
 
 

Do's

1) Cerebral salt wasting syndrome causes hypo-osmolar hyponatremia with lab parameters similar to that seen in SIADH. It is associated with conditions like hypovolemia, hypotension, neurosurgical procedure, and subarachnoid hemorrhage (within previous 10 days). It is treated as hypoosmolar hyponatremia.

2) While deciding the rate of normal saline for hypovolemia hyponatremia, consideration of the following factors are helpful: patient's BMI (faster rates for higher BMI), cardiac (slower rate for low ejection fraction) and renal function (slower rates for low GFRs).

3) Common causes of SIADH are, small cell lung cancer, intracranial pathology, increased intrathoracic pathology, medications (thiazides, SSRI, tricyclic antidepressant, narcotics, phenothiazine, carbamazepine)

4) Vaptans such as conivaptan (intravenous), and tolvaptans (oral preparations) can be used for resistant euvolemic, and hypervolemic hyponatremia. These are very expensive and should be initiated in hospital.

Don'ts

1) Serum sodium shouldn't be corrected faster than 0.5 meq/h as faster correction increases the risk for central pontine myelinolysis.

References


Template:WikiDoc Sources