Abstract and Introduction
Context: The development of diabetes insipidus (DI) following transsphenoidal resection of pituitary adenomas has been associated with higher postsurgical morbidity and longer hospitalizations. Identifying these patients promptly and efficiently can lead to improved health care outcomes.
Objective: We evaluated our institution's incidence of DI following pituitary adenoma resection and assessed for preoperative risk factors that were associated with postoperative DI.
Design: A retrospective review of 271 patients who underwent endoscopic endonasal resection of a pituitary adenoma between July 2010 and December 2016 by a single neurosurgical provider was completed.
Setting: All cases were from a single-center, academic institution.
Patients: Patients with a pituitary adenoma diagnosis confirmed on histology were included in the study. Those with previous surgery by a different provider were excluded.
Results: The incidence of DI at our institution was 16.6% (45 of 271 patients), with only 4% (11 patients) having permanent DI. The presence of visual abnormalities (CI 1.29 to 4.75), suprasellar extension (CI 1.36 to 6.88), and maximal tumor diameter (1.02 to 1.08) was significantly associated with an increased incidence of postoperative DI (P < 0.05). Hyperprolactinemia, tumor functionality, and cerebrospinal fluid exposure were not associated with higher rates of postoperative DI (P > 0.05).
Conclusion: Pituitary adenoma patients presenting with visual abnormalities, suprasellar extension, or large tumors are at higher risk of developing DI postoperatively. These patients warrant closer postoperative monitoring as well as adequate preoperative counseling to decrease their postsurgical morbidity.
Preoperative diagnosis of diabetes insipidus (DI) is rare in the setting of a pituitary adenoma and should prompt consideration of alternative diagnoses, such as craniopharyngioma or Rathke cleft cyst (RCC). Postoperative DI, however, is not a rare finding after sellar mass resections, with reported incidences typically ranging from 9% to 22% but up to 54% at some institutions.[1–10] Although not all patients develop DI after transsphenoidal surgery, those that do typically require longer hospitalizations and face a higher morbidity. Being able to avoid the adverse consequences from undiagnosed DI underscores the importance of correctly and efficiently identifying patients with DI following transsphenoidal surgery.
Unfortunately, the diagnosis of DI, especially in the hospitalized, postsurgical patient, is not always straightforward.[1,7] The effects of anesthesia, postoperative complications, medications, nasal packing, and perioperative intravenous fluid use can contribute to a confusing diagnostic evaluation.[1,7] An understanding of the postoperative antidiuretic hormone (ADH) pathophysiology and differential diagnoses of polyuria helps to clinically diagnose and test for DI. Following the diagnosis, close monitoring is required to evaluate treatment response and to determine whether the DI is transient, permanent, or part of the triphasic response.[1,7] The majority of postoperative DI is transient, requiring treatment of 1 week (~50%) up to 3 months (~80%). Permanent DI is much less common, with a reported incidence of 2% to 7%. The triphasic response is a postsurgical phenomenon that presents with a short period of DI, followed by the syndrome of inappropriate ADH secretion 5 to 7 days later, resulting in hyponatremia. Eventually, a proportion of these patients goes on to develop permanent DI. Although the full triphasic response is less common than permanent DI, with an incidence of 1.1%, managing these patients can be complicated and requires careful monitoring.
There have been studies that have retrospectively analyzed associations of preoperative and perioperative factors with DI that can be used to identify patients with a higher risk of developing postoperative DI. This could lead to closer postoperative monitoring of the high-risk population for a timely diagnosis and reduction in the postsurgical morbidity. Schreckinger et al. evaluated 172 endoscopic transsphenoidal surgeries and determined tumor volume and histopathology of RCC or craniopharyngioma were associated with postoperative DI. They also reported that a postoperative serum sodium (S[Na]) >145 mmol/mL or an increase of at least 2.5 mmol/L had 98% and 80% specificity, respectively, of developing DI. An evaluation for the incidence of postoperative DI by Kadir et al. at a single institution showed functioning pituitary adenomas (17.6%) were much less likely to be associated with DI than nonfunctioning pituitary adenomas (62.5%). A large, retrospective study of 881 patients by Nemergut et al. showed an 18.3% incidence of postoperative DI, with 12.4% requiring treatment at some point during hospitalization and only 2% requiring long-term treatment. Their analysis of these patients showed an intraoperative cerebrospinal fluid (CSF) leak to be strongly associated with DI (33.3% transient and 4.4% permanent). Similar to the previous study, histopathology showing RCC or craniopharyngioma was associated with increased incidence of DI. Corticotroph adenomas associated with Cushing disease had higher association with transient but not permanent DI. Interestingly, repeat operations were not associated with higher incidence of DI and microadenomas were more likely to experience transient DI than macroadenomas.
The purpose of our study was to review our institution's experience with patients with pituitary adenoma following endoscopic endonasal resection to identify preoperative factors that were associated with the development of postoperative DI.
J Endo Soc. 2018;2(9):1010-1019. © 2018 Endocrine Society