Preoperative Assessment of Adult Patients for Intracranial Surgery

Table 3

Differences between diabetes insipidus and syndrome of inappropriate antidiuretic hormone.

	Diabetes insipidus	Syndrome of inappropriate
		antidiuretic hormone
Presentation	Polyuria Thirst (awake patients)	Hyponateriamia
Serum sodium	Increased >145 mEq/L	Decreased <135 mEq/L
Serum osmolarity	High >310 mOsm/L	Low/hypotonic <275 mOsm/L
Urine volume	Increased volume >4 L/day	Low
Treatment	Supportive fluid replacement and DDAVP	Fluid restriction with hypertonic sodium correction if serum sodium <120 mEq/L