Isolated second-phase diabetes insipidus post-transsphenoidal surgery.

Area of Science:

• Endocrinology
• Neurosurgery
• Internal Medicine

Background:

• Transsphenoidal surgery is a common procedure for pituitary adenomas.
• Post-surgical complications can include hormonal imbalances and electrolyte disturbances.
• Growth hormone-secreting pituitary adenomas require specific surgical and post-operative management.

Observation:

• A 57-year-old woman experienced severe lethargy, dizziness, and nausea one week post-transsphenoidal resection of a pituitary adenoma.
• She presented with profound hyponatremia (115 mmol/L) but remained neurologically intact and euvolemic.
• Initial management involved fluid restriction.

Findings:

• The patient was diagnosed with isolated second-phase diabetes insipidus, a form of symptomatic hypoosmolar hyponatremia.
• This condition typically manifests 7-10 days after transsphenoidal surgery.
• Fluid restriction led to a significant increase in sodium levels (to 131 mmol/L) over 4 days.

Implications:

• Isolated second-phase diabetes insipidus is a recognized, albeit less common, post-surgical complication.
• Prompt diagnosis and management, including fluid restriction, are crucial for patient recovery.
• This case highlights the importance of monitoring electrolyte balance after pituitary surgery.