How fast should hyponatremia be corrected?

For chronic hyponatremia (> 48 hours or unknown duration), sodium should be raised by no more than 8–10 mEq/L in the first 24 hours and no more than 18 mEq/L in 48 hours to prevent osmotic demyelination syndrome (ODS). For acute symptomatic hyponatremia (< 48 hours), rapid correction of 1–2 mEq/L per hour for the first 2–4 hours is appropriate.

What is osmotic demyelination syndrome?

Osmotic demyelination syndrome (ODS, formerly central pontine myelinolysis) results from overly rapid correction of chronic hyponatremia. It causes irreversible neurological damage including quadriparesis, pseudobulbar palsy, and locked-in syndrome. Risk factors include alcoholism, malnutrition, liver disease, and hypokalemia.

How do you correct sodium for hyperglycemia?

For each 100 mg/dL increase in glucose above 100, sodium decreases by approximately 1.6–2.4 mEq/L. The corrected sodium formula: Corrected Na = Measured Na + 1.6 × (Glucose − 100) / 100. Some experts use a correction factor of 2.4 when glucose > 400 mg/dL.

What fluids are used to correct hyponatremia?

Hypertonic saline (3% NaCl) is used for severe symptomatic hyponatremia or emergencies. Fluid restriction is first-line for euvolemic hyponatremia (SIADH). Normal saline (0.9% NaCl) is used for hypovolemic hyponatremia. Vasopressin receptor antagonists (tolvaptan) may be used for refractory SIADH under close monitoring.

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Sodium Correction for Hyperglycemia

Calculate the corrected serum sodium in the setting of hyperglycemia using Katz and Hillier formulas.

Eingaben

Measured Sodium (mEq/L)

Serum Glucose (mg/dL)

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Enter sodium and glucose values.

Katz (1973)Na + 1.6 × [(Glucose − 100) / 100]

Hillier (1999)Na + 2.4 × [(Glucose − 100) / 100]

Haftungsausschluss: Nur zu Bildungszwecken. Kein Ersatz für klinisches Urteil.

Anwendung

Use this whenever sodium appears low in the setting of significant hyperglycemia (typically glucose > 200 mg/dL) — particularly in DKA and HHS — to determine the "true" sodium status.

Clinical pearls

The Katz correction (1.6 mEq/L per 100 mg/dL glucose above 100) is the classic formula but may underestimate at very high glucose levels.
The Hillier correction (2.4 mEq/L per 100 mg/dL) is more accurate at glucose levels > 400 mg/dL.
If corrected Na is elevated, the patient has a free water deficit despite appearing hyponatremic — critical for fluid management in DKA/HHS.
Monitor corrected sodium during DKA treatment: as glucose falls with insulin, sodium should rise proportionally.

References

Katz MA. Hyperglycemia-induced hyponatremia — calculation of expected serum sodium depression. N Engl J Med. 1973;289(16):843-844.
Hillier TA, et al. Hyponatremia: evaluating the correction factor for hyperglycemia. Am J Med. 1999;106(4):399-403.

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Über dieses Tool

Why Correct Sodium for Hyperglycemia?

Glucose is an effective osmole that draws water from the intracellular to the extracellular space via osmosis. This dilutes the serum sodium, producing a "dilutional" or "translocational" hyponatremia. The measured sodium therefore underestimates the patient's true sodium status. Correcting the sodium for the glucose level reveals what the sodium would be if glucose were normal, which is essential for determining whether the patient is truly hyponatremic, eunatremic, or even hypernatremic — which has critical implications for fluid management in diabetic ketoacidosis (DKA) and hyperosmolar hyperglycemic state (HHS).

Katz vs. Hillier Correction

The original Katz correction factor (1973) adds 1.6 mEq/L to the measured sodium for every 100 mg/dL of glucose above 100 mg/dL. This was based on theoretical calculations and has been the standard for decades. However, Hillier et al. (1999) demonstrated through empirical data that the relationship between glucose and sodium is not linear and that at higher glucose levels, the correction factor should be 2.4 mEq/L per 100 mg/dL. Most current guidelines recommend using the Katz factor for moderate hyperglycemia (200–400 mg/dL) and the Hillier factor for severe hyperglycemia (> 400 mg/dL), or simply reporting both.

Clinical Significance in DKA/HHS

In DKA and HHS, the corrected sodium is essential for guiding fluid therapy. If the corrected sodium is low, the patient has true hyponatremia and may benefit from isotonic saline. If the corrected sodium is normal or elevated, the patient has a significant free water deficit requiring hypotonic fluid replacement. During treatment, sodium should rise as glucose falls — if sodium drops while glucose drops, this may indicate excess free water administration or worsening cerebral edema risk, particularly in pediatric patients.

🔑 Klinische Hinweise

A rising corrected sodium during DKA treatment that exceeds 145 mEq/L suggests free water deficit — consider adding free water to fluids.
In pediatric DKA, a sodium that fails to rise appropriately as glucose falls is a warning sign for cerebral edema.
Use the Hillier (2.4) correction when glucose > 400 mg/dL for more accurate estimation.
This correction applies ONLY to hyperglycemia — do not use for other causes of pseudohyponatremia (lipemia, paraproteinemia).

Schlüsselreferenzen

Katz MA. Hyperglycemia-induced hyponatremia. N Engl J Med. 1973;289(16):843-844.
Hillier TA, et al. Hyponatremia: evaluating the correction factor for hyperglycemia. Am J Med. 1999;106(4):399-403.
Kitabchi AE, et al. Hyperglycemic crises in adult patients with diabetes. Diabetes Care. 2009;32(7):1335-1343.

Formel zuletzt überprüft: Februar 2026