Nephrogenic diabetes insipidus presenting after head trauma

Area of Science:

• Nephrology
• Endocrinology
• Neuroscience

Background:

• Head trauma is a common cause of central diabetes insipidus (DI).
• Nephrogenic DI (NDI) is a less common cause of polyuria and hypernatremia.
• Previous lithium use can be associated with renal impairment and DI.

Observation:

• A patient with bipolar disorder and a history of lithium use developed polyuria and hypernatremia after head trauma.
• Aggressive sodium and volume replacement exacerbated the polyuria.
• The patient did not respond to antidiuretic hormone (ADH) or ADH-like treatments.

Findings:

• The lack of response to ADH confirmed nephrogenic diabetes insipidus.
• The case underscores the importance of electrolyte-free osmolar clearance in managing hypernatremia.
• Persistent DI and mild renal impairment were noted, potentially linked to past lithium exposure.

Implications:

• Highlights the differential diagnosis of polyuria post-head trauma, including NDI.
• Stresses the critical role of appropriate fluid and electrolyte management in hypernatremia.
• Suggests considering past lithium exposure as a contributing factor to DI and renal dysfunction.