What isotonic fluids are used to treat a patient with suspected diabetes insipidus (DI) due to traumatic brain injury (TBI), presenting with polyuria, hypernatremia, and hypotension?

From the Guidelines

For a patient with suspected diabetes insipidus following traumatic brain injury, presenting with high urine output, hypernatremia, and hypotension, immediate treatment should include isotonic 0.9% normal saline for volume resuscitation, as recommended by the most recent guideline evidence 1.

Key Considerations

• Initial fluid administration should be rapid to address hypotension, with a goal of restoring hemodynamic stability.
• Once the patient is stabilized, desmopressin (DDAVP) should be administered to address the underlying diabetes insipidus.
• The typical starting dose is 1-2 mcg IV or 10-20 mcg intranasally every 12 hours, with dose adjustments based on urine output and serum sodium levels.
• Careful monitoring of fluid status, electrolytes (especially sodium), urine output, and urine specific gravity is essential.

Rationale

• The use of isotonic fluids such as 0.9% sodium chloride is recommended for hypotensive patients, as stated in the European guideline on management of major bleeding and coagulopathy following trauma: sixth edition 1.
• Although other studies suggest avoiding salt-containing solutions in patients with nephrogenic diabetes insipidus, the context of traumatic brain injury and hypotension prioritizes the use of isotonic fluids for initial volume resuscitation 1.
• The goal is to reduce urine output to less than 200 mL/hour and gradually normalize serum sodium (decrease by no more than 10 mEq/L in 24 hours to avoid cerebral edema).

Monitoring and Adjustments

• Close observation of clinical status, including neurological condition, fluid balance, weight, and electrolytes, is crucial.
• Placement of a urinary catheter should be considered to ensure proper monitoring of diuresis.
• Fluid composition and administration rates may need to be adjusted based on the patient's response to treatment and underlying condition.

From the FDA Drug Label

The FDA drug label does not answer the question.

From the Research

Isotonic Fluids for Treating Diabetes Insipidus

To treat a patient with suspected diabetes insipidus (DI) due to traumatic brain injury (TBI), presenting with polyuria, hypernatremia, and hypotension, the following isotonic fluids can be used:

• 0.9% sodium chloride solution (10 mL/kg) to restore volemia in a shocked patient 2
• 5% dextrose in water with an infusion rate that slightly exceeds the urine output 2

Prevention of Hyponatremia

Isotonic fluids are preferred over hypotonic fluids to prevent hospital-acquired hyponatraemia:

• 0.9% saline is an isotonic solution that can be used as a maintenance fluid to prevent hyponatremia 3, 4
• Hypotonic IV solutions increase the incidence of hospital-acquired hyponatraemia 3
• The use of isotonic fluids prevents iatrogenic hyponatremia in pediatrics 4

Management of Hypernatremic Dehydration

In patients with nephrogenic diabetes insipidus (NDI), hypernatremic dehydration should always be suspected:

• 5% dextrose in water with an infusion rate that slightly exceeds the urine output is recommended for fluid replenishment 2
• 0.9% NaCl solution (10 mL/kg) should only be used to restore the volemia in a shocked NDI patient 2