Increased oxytocin release precedes hyponatremia after pituitary surgery

Urinary oxytocin secretion after pituitary surgery, early arginine vasopressin deficiency and syndrome of inappropriate antidiuresis

PURPOSE

Transient arginine vasopressin deficiency (AVP-D), previously called diabetes insipidus, is a well-known complication of transsphenoidal pituitary surgery (TPS) with no definite predictive biomarker to date making it difficult to anticipate. While oxytocin (OXT) was previously suggested as a possible biomarker to predict syndrome of inappropriate diuresis (SIAD)-related hyponatraemia after TPS, its secretion in patients presenting with AVP-D remains poorly understood. We therefore hypothesized that OXT might present a different secretion in the case of AVP-D which would support its potential as an early biomarker of AVP-D. Moreover, we hypothesized that abnormal secretion of OXT might occur later on, notably with SIAD.

METHODS

We measured the urinary output of OXT in 67 consecutive patients subjected to TPS and compared the values of oxytocin between time-points and OXT ratio between groups. The primary endpoint of our study was to identify a difference in urinary OXT excretion in patients suffering from AVP-D compared to patients remaining normonatraemic. As a secondary endpoint, we compared the evolution of OXT secretion after the diagnosis of AVP-D in both groups, comparing the patients that later developed SIAD with the ones that did not.

RESULTS

Patients developing AVP-D showed a delay in the increase of OXT secretion after TPS as shown by a significantly lower ratio of OXT between the first postoperative day and the day of surgery (0.88 VS 1.68, p = 0.0162, IC:0.2979-0.2642) but a significantly higher ratio of OXT between the fourth and the first postoperative days (1.17 VS 0.53, p = 0.0006, IC:-2.109-0.6092). Moreover, normonatraemic patients that did not show normalization of OXT levels at day 4 after surgery tended to develop SIAD later on.

CONCLUSION

Taken together, these results show for the first time that OXT release might help predict AVP-D after TPS and differentiate it from other pathologies of water-sodium balance.

Desmopressin to prevent and treat bleeding in pregnant women with an inherited bleeding disorder: a systematic literature review

BACKGROUND

Although desmopressin (DDAVP) is an accessible and inexpensive hemostatic drug, its use in pregnancy is still debated due to safety uncertainties.

OBJECTIVES

We aimed to review the safety and effectiveness of DDAVP in women with an inherited bleeding disorder during pregnancy and delivery.

METHODS

Databases were searched for articles up to July 25, 2022, reporting maternal and/or neonatal outcomes. PRISMA methodology for systematic reviews and meta-analyses was followed (PROSPERO CRD42022316490).

RESULTS

Fifty-three studies were included, comprising 273 pregnancies. Regarding maternal outcomes, DDAVP was administered in 73 women during pregnancy and in 232 during delivery. Safety outcome was reported in 245 pregnancies, with severe adverse events reported in 2 (1%, hyponatremia with neurologic symptoms). Overall, DDAVP was used as monotherapy in 234 pregnancies, with effectiveness reported in 153 pregnancies (82% effective; 18% ineffective). Regarding neonatal outcomes, out of 60 pregnancies with reported neonatal outcomes after DDAVP use during pregnancy, 2 children (3%) had a severe adverse event (preterm delivery n = 1; fetal growth restriction n = 1). Of the 232 deliveries, 169 neonates were exposed to DDAVP during delivery, and in 114 neonates, safety outcome was reported. Two children (2%) experienced a moderate adverse event (low Apgar score n = 1; transient hyperbilirubinemia not associated with DDAVP n = 1).

CONCLUSION

DDAVP use during pregnancy and delivery seems safe for the mother, with special attention to the occurrence of hyponatremia and for the child, especially during delivery. However, due to poor study designs and limited documentation of outcomes, a well-designed prospective study is warranted.

Machine learning models predict delayed hyponatremia post-transsphenoidal surgery using clinically available features

PURPOSE

Delayed hyponatremia (DHN), a unique complication, is the leading cause of unexpected readmission after pituitary surgery. Therefore, this study aimed to develop tools for predicting postoperative DHN in patients undergoing endoscopic transsphenoidal surgery (eTSS) for pituitary neuroendocrine tumors (PitNETs).

METHODS

This was a single-center, retrospective study involving 193 patients with PitNETs who underwent eTSS. The objective variable was DHN, defined as serum sodium levels < 135 mmol/L at ≥ 1 time between post operative days 3 and 9. We trained four machine learning models to predict this objective variable using the clinical variables available preoperatively and on the first postoperative day. The clinical variables included patient characteristics, pituitary-related hormone levels, blood test results, radiological findings, and postoperative complications.

RESULTS

The random forest (RF) model demonstrated the highest (0.759 ± 0.039) area under the curve of the receiver operating characteristic curve (ROC-AUC), followed by the support vector machine (0.747 ± 0.034), the light gradient boosting machine (LGBM: 0.738 ± 0.026), and the logistic regression (0.710 ± 0.028). The highest accuracy (0.746 ± 0.029) was observed in the LGBM model. The best-performing RF model was based on 24 features, nine of which were clinically available preoperatively.

CONCLUSIONS

The proposed machine learning models with pre- and post-resection features predicted DHN after the resection of PitNETs.

Diaphragma sellae sinking can predict the onset of hyponatremia after transsphenoidal surgery for pituitary adenomas

PURPOSE

Sinking of the diaphragma sellae (DS) may stretch the pituitary stalk, which in turn impairs neurohypophyseal function; thus, it may play a role in the development of postoperative hyponatremia. We aimed to assess the factors influencing the development of hyponatremia after transsphenoidal surgery (TSS) for pituitary adenomas and analyze the effect of DS sinking on hyponatremia.

METHODS

After applying the inclusion and exclusion criteria, we retrospectively analyzed the clinical data of patients with pituitary adenoma who underwent TSS. The pituitary gland was scanned using a 3.0-T magnetic resonance imaging, and sagittal and coronal images were acquired. We evaluated the following: preoperative and postoperative hypothalamus‒pituitary‒thyroid axis function, hypothalamus‒pituitary‒adrenal axis function, intra-operative cerebrospinal fluid leaks, diabetes insipidus, hyponatremia, time from the day of surgery to the day of discharge, and time of hyponatremia onset.

RESULTS

Of the 460 patients who had microscopic TSS for pituitary adenoma, 83 experienced postoperative hyponatremia. Hyponatremia occurred approximately 5.25 days postoperatively and persisted for 5.54 days. The lowest average blood sodium level was 123.9 mEq/L, which occurred at 7.49 days after surgery. Logistic regression analysis showed that the risk of hyponatremia was greater for patients with a significant DS sinking depth, a large pituitary stalk deviation angle difference, and a longer postoperative "measurable pituitary stalk". The difference in blood sodium levels between pre-TSS and 2 days post-TSS was also an independent predictor of postoperative hyponatremia onset.

CONCLUSION

DS sinking plays an important role in predicting hyponatremia onset after TSS for pituitary adenomas.

The Difference Between Preoperative and Postoperative Pituitary Stalk Deviation Angles Can Predict Delayed Hyponatremia After Transsphenoidal Surgery

OBJECTIVE

Our aim was to assess the factors influencing the development of delayed hyponatremia after transsphenoidal surgery (TSS) for pituitary adenomas and analyze the effect of the difference between preoperative and postoperative pituitary stalk deviation angles on delayed hyponatremia.

METHODS

A retrospective study was performed on the clinical data of patients with pituitary adenomas who were treated with TSS at a single institution. On the basis of the observation of indicators such as pituitary stalk deviation angle and length of "measurable pituitary stalk" on magnetic resonance imaging, we determined the predictors of postoperative delayed hyponatremia through univariate and multivariate analyses.

RESULTS

Microscopic TSS was performed in 422 patients with pituitary adenoma, of whom 66 experienced postoperative delayed hyponatremia. Logistic regression analysis showed that the risk of delayed hyponatremia was greater for patients with a large difference between preoperative and postoperative pituitary stalk deviation angle (odds ratio = 1.040, 95% confidence interval: 1.018-1.051; P < 0.001) and a large difference in the "measurable pituitary stalk" (odds ratio = 1.128, 95% confidence interval: 1.011-1.258; P = 0.032), and patients with high blood sodium on the second day after surgery have a lower probability of developing delayed hyponatremia.

CONCLUSIONS

This study is the first to suggest the important role of the difference between preoperative and postoperative pituitary stalk deviation angles in predicting the development of delayed hyponatremia after TSS for pituitary adenomas.