What finding indicates a child may be developing diabetes insipidus after a head injury?

The finding that suggests a child may be developing diabetes insipidus after a head injury is an elevated sodium level of 155 mEq/L. Diabetes insipidus, particularly central diabetes insipidus, can occur following a head injury due to damage to the hypothalamus or pituitary gland, which disrupts the production of antidiuretic hormone (ADH). When ADH levels decrease, the body's ability to concentrate urine is impaired, resulting in excessive urination (polyuria) and consequently, a loss of water that can lead to hypernatremia (an elevated sodium level).

A sodium level of 155 mEq/L is indicative of this imbalance and may signal the body's response to fluid loss associated with diabetes insipidus. Monitoring sodium levels is crucial as they provide insight into the child's hydration status and potential complications related to the condition.

The other findings presented do not directly indicate the onset of diabetes insipidus. For instance, a high urine specific gravity typically indicates concentrated urine, which is contrary to what is expected in diabetes insipidus; a blood glucose level of 45 mg/dL reflects hypoglycemia rather than indicating diabetes insipidus; and a urine output of 35 mL/hr does not