Hyponatremia: Difference between revisions
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==Treatment by Patient Status<ref>Spasovski et al. Clinical practice guideline on diagnosis and treatment of hyponatraemia. Nephrol Dial Transplant (2014) 0: 1–39. [http://ndt.oxfordjournals.org/content/early/2014/02/21/ndt.gfu040.full.pdf fulltext]</ref>==
==Treatment by Patient Status<ref>Spasovski et al. Clinical practice guideline on diagnosis and treatment of hyponatraemia. Nephrol Dial Transplant (2014) 0: 1–39. [http://ndt.oxfordjournals.org/content/early/2014/02/21/ndt.gfu040.full.pdf fulltext]</ref>==
''Must have sufficient confidence that the symptoms are '''caused''' by hyponatraemia''
''Must have sufficient confidence that the symptoms are '''caused''' by hyponatraemia''
===Symptomatic===
===Severe Symptoms (See Clinical Features)===
*'''Adults:''' 3% NS 100cc bolus over 10min; repeat after 10min x1 if no improvement
*'''Adults:'''  
**Each 100 ml will raise sodium by ~2 mmol/l
*#3% hypertonic saline 150 mL bolus over 20 min
**In general, 200-400 mL of 3% NaCl is reasonable dose in most adult patients with severe symptomatic hyponatremia, which may be given IV over 1-2 hr until resolution of seizures.   
*#Check serum sodium concentration after 20 min
*#Repeat infusion of 150 ml 3% hypertonic saline for the next 20 min
*#Repeat twice or until a target of 5 mmol/l increase in serum sodium concentration is achieved
*#*Each 100 mL will raise sodium by ~2 mmol/l
*#*In general, 200-400 mL of 3% hypertonic saline is reasonable dose in most adult patients with severe symptomatic hyponatremia, which may be given IV over 1-2 hr until resolution of seizures.   
*#PO fluid restrict
 
7.1.1.4. Manage patients with severely symptomatic
hyponatraemia in an environment where close
biochemical and clinical monitoring can be
provided (not graded).
 
 
 
 
 
*'''Pediatrics:''' 2 cc/kg  of 3% over 10-60 minutes can be infused with a repeat of up to 3 times.<ref>Moritz ML, Ayus JC. 100cc 3% sodium chloride bolus: a novel treatment for hyponatremic encephalopathy. Metab Brain Dis. 2010 Mar; 25(1): 91-6.</ref>
*'''Pediatrics:''' 2 cc/kg  of 3% over 10-60 minutes can be infused with a repeat of up to 3 times.<ref>Moritz ML, Ayus JC. 100cc 3% sodium chloride bolus: a novel treatment for hyponatremic encephalopathy. Metab Brain Dis. 2010 Mar; 25(1): 91-6.</ref>
*Fluid restrict


===Asymptomatic===
===Asymptomatic===

Revision as of 12:25, 5 October 2017

Background

  • Defined as sodium concentration <135meq/L[1]
  • Patients often not symptomatic until <120meq/L although this level varies by patients and may be higher if the change occurred abruptly[2]
  • Generally accepted recommendations are to avoid correction of more than 12 mmol/L/day (0.5mmol/L/hr) to avoid central pontine myelinolysis. Faster correction (1-2mmol/L/hr) is acceptable with 3% hypertonic saline if the patient is seizing.[3]

Clinical Features

Hyponatremia Symptoms by Severity[4]

Severity NOT severe Moderately severe Severe
Symptoms
  • Gait disturbances
  • Falls
  • Concentration
  • Cognitive deficits

Symptoms from Rapid Correction of Sodium

Differential Diagnosis of Hypotonic Hyponatremia (by Volume Status)

Hypovolemic

Renal Causes

  • Thiazide diuretic use
  • Na-wasting nephroathy (RTA, CRF)
  • Osmotic diuresis (glucose, urea)
  • Aldosterone deficiency

Extra-renal Causes

Hypervolemic

Euvolemic

Pseudohyponatremia

  • Hyperglycemia
    • Na+ decreases by 2.4mEq/L for each 100mg/dL increase in glucose over 100mg/dL[7]
  • Displaced sodium in lab specimen
    • Hyperlipidemia
    • Hyperproteinemia

Evaluation

Work-Up

Prior to giving treatment

  • Urine
    • Urinalysis
    • Urine electrolytes
    • Urine urea
    • urine uric acid
    • urine osmolality
    • urine creatinine
  • Serum
    • Chemistry
    • Serum osmolality
    • Uric acid
    • TSH
    • Cortisol

Diagnosis

True serum sodium (corrected) based on serum glucose[8]
Algorithm for hyponatremia diagnosis
  1. Correct for glucose (see table)
  2. Determine volume status
  3. Calculated osm (in true hyponatremia the osm is reduced)

Hypertonic Hyponatremia

Defined as osmolarity > 295mmol/L with the following causes:

  1. Hyperglycemia
    • Sodium decreases by 2.4mEq/L for each 100mg/dL increase in glucose over 100mg/dL[9]
  2. Mannitol excess

Isotonic (pseudo) hyponatremia

Defined as osmolarity > 275-295mmol/L. Often referred to as pseudo hyponatremia because the elevated lipids or proteins interfere with the laboratory sodium reading. The following are common causes:

  1. Hyperlipidemia
  2. Hyperproteinemia

Hypotonic Hyponatremia

Defined as an osmolarity < 275 mmol/L and categorized as hypovolemic, hypervolemic or euvolemic

Treatment by Patient Status[10]

Must have sufficient confidence that the symptoms are caused by hyponatraemia

Severe Symptoms (See Clinical Features)

  • Adults:
    1. 3% hypertonic saline 150 mL bolus over 20 min
    2. Check serum sodium concentration after 20 min
    3. Repeat infusion of 150 ml 3% hypertonic saline for the next 20 min
    4. Repeat twice or until a target of 5 mmol/l increase in serum sodium concentration is achieved
      • Each 100 mL will raise sodium by ~2 mmol/l
      • In general, 200-400 mL of 3% hypertonic saline is reasonable dose in most adult patients with severe symptomatic hyponatremia, which may be given IV over 1-2 hr until resolution of seizures.
    5. PO fluid restrict

7.1.1.4. Manage patients with severely symptomatic hyponatraemia in an environment where close biochemical and clinical monitoring can be provided (not graded).



  • Pediatrics: 2 cc/kg of 3% over 10-60 minutes can be infused with a repeat of up to 3 times.[11]

Asymptomatic

Step 1

Calculate total body water[12]

  • TBW(kg) = Wt(kg) x 0.6 = [Wt(lb) x 0.45] x 0.6 = Wt(lb) x 0.27

Step 2

Calculate mEq deficit

  • (Desired Na - Measured Na) ~ must be ≤ 10

Step 3

Calculate NS rate to be given over 24hr

  • NS rate (cc/hr) = TBW x mEq deficit x 0.27
  • If using 3% sodium chloride (to avoid volume overload) divide above rate by 3.33

Treatment by Type of Hyponatremia

Hypertonic hyponatremia

  • Correct underlying disorder which is often hyperglycemia[13]
  • Often volume depleted due to osmotic diuresis and normal saline provides adequate volume repletion

Isotonic (pseudo) hyponatremia

  • No treatment needed [13]

Hypotonic hyponatremia

  1. Hypovolemic
    • Give NS but be cautious of raising the serum sodium more than 12 mmol/L/day (0.5mmol/L/hr) and causing central pontine demylinosis[3]
  2. Euvolemic[13]
    • Water restrict
    • Treat underlying cause
  3. Hypervolemic
    • Water restriction
    • Diuresis
    • Treat underlying cause

Na Therapy

Max correction 10mEq/L in first 24hr and 18mEq/L in first 48hr (lowers risk of central pontine demylinosis) [14]

Sodium Containing fluid Concentrations
Fluid type Sodium Concentration
1/2 Normal Saline 77 mEq/L
Normal Saline 154 mEq/L
Lactated Ringers 130 mEq/L
3% Saline 513 mEq/L

Disposition

  • Admit if symptomatic or if Na <125mEq/L

See Also

External Links

References

  1. ↑ Upadhyay A, Jaber BL, Madias NE. Epidemiology of hyponatremia. Seminars in Nephrology 2009 29 227–238
  2. ↑ Spasovski G. et al. Clinical practice guideline on diagnosis and treatment of hyponatraemia. Nephrol Dial Transplant. 2014
  3. ↑ 3.0 3.1 Adrogué HJ, Madias NE. Hyponatremia. N Engl J Med. 2000 May 25;342(21):1581-9.
  4. ↑ Spasovski et al. Clinical practice guideline on diagnosis and treatment of hyponatraemia. Nephrol Dial Transplant (2014) 0: 1–39. fulltext
  5. ↑ Review of Drug-Induced Hyponatremia. Am J Kidney Dis 2008;52:144
  6. ↑ Kate M, Grover S. Bupropion-Induced Hyponatremia. General Hospital Psychiatry Volume 35, Issue 6, November–December 2013, 681-683.
  7. ↑ Hillier TA, Abbott RD & Barrett EJ. Hyponatremia: evaluating the correction factor for hyperglycemia. American Journal of Medicine 1999 106 399–403
  8. ↑ Spasovski et al. Clinical practice guideline on diagnosis and treatment of hyponatraemia. Nephrol Dial Transplant (2014) 0: 1–39. fulltext
  9. ↑ Hillier TA, Abbott RD & Barrett EJ. Hyponatremia: evaluating the correction factor for hyperglycemia. American Journal of Medicine 1999 106 399–403
  10. ↑ Spasovski et al. Clinical practice guideline on diagnosis and treatment of hyponatraemia. Nephrol Dial Transplant (2014) 0: 1–39. fulltext
  11. ↑ Moritz ML, Ayus JC. 100cc 3% sodium chloride bolus: a novel treatment for hyponatremic encephalopathy. Metab Brain Dis. 2010 Mar; 25(1): 91-6.
  12. ↑ The hyponatremia formulas do not work so well (Clin J Am Soc Nephrol 2007;2:1110 and Nephrol Dial Transplant 2006;21:1564)
  13. ↑ 13.0 13.1 13.2 Schrier RW, Bansal S. Diagnosis and management of hyponatremia in acute illness. Curr Opin Crit Care 2008;14:627-34
  14. ↑ Nagler EV1, Vanmassenhove J, van der Veer SN et al. Diagnosis and treatment of hyponatremia: a systematic review of clinical practice guidelines and consensus statements. BMC Med. 2014 Dec 11;12:1
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