How to correct severe hyponatremia (sodium level of 117 mmol/L)?

Management of Severe Hyponatremia (Sodium 117 mmol/L)

For a sodium level of 117 mmol/L, you must first determine symptom severity: if the patient has severe neurological symptoms (seizures, altered mental status, coma), immediately administer 3% hypertonic saline with a target correction of 6 mmol/L over 6 hours; if asymptomatic or mildly symptomatic, implement fluid restriction to 1-1.5 L/day and discontinue any contributing medications, particularly diuretics. 1

Initial Assessment

Before initiating treatment, rapidly assess three critical factors:

• Symptom severity: Determine if severe symptoms are present (seizures, coma, altered mental status, cardiorespiratory distress) versus mild symptoms (nausea, headache, weakness) versus asymptomatic 1, 2
• Volume status: Classify as hypovolemic (orthostatic hypotension, dry mucous membranes, poor skin turgor), euvolemic (no edema, normal blood pressure), or hypervolemic (edema, ascites, jugular venous distention) 1
• Acuity: Establish if onset is acute (<48 hours) versus chronic (>48 hours), as chronic hyponatremia carries higher risk of osmotic demyelination with rapid correction 1

Obtain immediate laboratory studies including serum osmolality, urine sodium, urine osmolality, and assess renal, thyroid, and adrenal function 1

Treatment Based on Symptom Severity

Severe Symptomatic Hyponatremia (Medical Emergency)

Administer 3% hypertonic saline immediately with the following protocol 1, 3, 2:

• Give 100 mL boluses of 3% saline over 10 minutes, repeatable up to three times at 10-minute intervals until symptoms improve 1
• Target correction: 6 mmol/L increase over the first 6 hours or until severe symptoms resolve 1
• Critical safety limit: Do not exceed 8 mmol/L correction in 24 hours to prevent osmotic demyelination syndrome 1, 3
• Monitor sodium levels every 2 hours during initial correction 1
• Require ICU admission for continuous monitoring 1

Asymptomatic or Mildly Symptomatic Hyponatremia

Do not use hypertonic saline for patients without severe symptoms 1, 2. Instead:

• Implement fluid restriction to 1-1.5 L/day as first-line treatment 1
• Discontinue diuretics immediately if present 1
• Target slower correction rate of 4-6 mmol/L per day 1
• Monitor sodium levels every 4-6 hours initially, then daily 1

Treatment Based on Volume Status

Hypovolemic Hyponatremia

• Administer isotonic (0.9%) saline for volume repletion 1
• Discontinue any diuretics 1
• Once euvolemic, reassess and adjust treatment based on sodium response 1

Euvolemic Hyponatremia (SIADH)

• Fluid restriction to 1 L/day is the cornerstone of treatment 1
• If no response after 24-48 hours, add oral sodium chloride 100 mEq three times daily 1
• Consider urea or vaptans for resistant cases 1, 2

Hypervolemic Hyponatremia (Cirrhosis, Heart Failure)

• Fluid restriction to 1-1.5 L/day for sodium <125 mmol/L 1
• Discontinue diuretics temporarily 1
• Consider albumin infusion in cirrhotic patients 1
• Avoid hypertonic saline unless life-threatening symptoms present, as it worsens fluid overload 1

Critical Correction Rate Guidelines

The maximum safe correction rate is 8 mmol/L in 24 hours for most patients 1, 3, 2. However, high-risk populations require even slower correction:

High-Risk Patients (Require 4-6 mmol/L per day maximum)

Patients with the following conditions are at increased risk for osmotic demyelination syndrome 1, 3:

• Advanced liver disease or cirrhosis
• Chronic alcoholism
• Severe malnutrition
• Hypokalemia or hypophosphatemia
• Prior history of encephalopathy

For these patients, limit correction to 4-6 mmol/L per day and do not exceed 8 mmol/L in 24 hours 1, 3

Management of Overcorrection

If sodium correction exceeds 8 mmol/L in 24 hours 1:

• Immediately discontinue current fluids and switch to D5W (5% dextrose in water) 1
• Administer desmopressin to slow or reverse the rapid rise in serum sodium 1
• Target relowering to bring total 24-hour correction to no more than 8 mmol/L from baseline 1
• Monitor for signs of osmotic demyelination syndrome (dysarthria, dysphagia, oculomotor dysfunction, quadriparesis) which typically occur 2-7 days after rapid correction 1

Special Considerations

Neurosurgical Patients

Distinguish between SIADH and cerebral salt wasting (CSW), as treatment differs fundamentally 1:

• CSW requires volume and sodium replacement, not fluid restriction 1
• Consider fludrocortisone for CSW in subarachnoid hemorrhage patients 1
• Never use fluid restriction in patients at risk for vasospasm 1

Cirrhotic Patients

• Hyponatremia at this level increases risk of spontaneous bacterial peritonitis (OR 3.40), hepatorenal syndrome (OR 3.45), and hepatic encephalopathy (OR 2.36) 1
• Use more conservative correction rates (4-6 mmol/L per day) due to higher osmotic demyelination risk 1
• Albumin infusion may improve sodium levels 1

Common Pitfalls to Avoid

• Overly rapid correction exceeding 8 mmol/L in 24 hours causes osmotic demyelination syndrome 1, 3
• Using fluid restriction in cerebral salt wasting worsens outcomes 1
• Inadequate monitoring during active correction 1
• Using hypertonic saline in hypervolemic hyponatremia without life-threatening symptoms 1
• Ignoring high-risk factors that require slower correction rates 1, 3

Monitoring Protocol

• Severe symptoms: Check sodium every 2 hours during initial correction 1
• After symptom resolution: Check sodium every 4 hours 1
• Stable patients: Check sodium daily 1
• Calculate sodium deficit using: Desired increase in Na (mEq/L) × (0.5 × ideal body weight in kg) 1