The incidence of anterior pituitary hormone deficiencies in patients with microprolactinoma and idiopathic hyperprolactinaemia.

INTRODUCTION: Patients with microprolactinoma and idiopathic hyperprolactinaemia are not generally considered to be at risk of hypopituitarism and are therefore not routinely screened for this abnormality. In our clinical practice, we have observed a number of patients with nonmacroadenomatous hyperprolactinaemia to have anterior pituitary hormone deficits. AIMS: We aimed to establish the frequency and clinical significance of anterior pituitary hormone deficiencies, comparing patients with radiologically proven microprolactinomas and patients with idiopathic hyperprolactinaemia. STUDY DESIGN: We retrospectively examined the casenotes of 206 patients with hyperprolactinaemia from our centre. Patients who did not fit the profile of surgically naïve microprolactinoma or idiopathic hyperprolactinaemia or who had incomplete data were excluded, resulting in a study group of 56 patients. RESULTS: A total of 35 patients with MRI evidence of microprolactinoma were identified, three (8.57%) of whom had one or more anterior pituitary hormone deficiencies. A total of 21 patients with MRI-negative idiopathic hyperprolactinaemia were identified, nine (42%) of whom had one or more anterior pituitary hormone deficiencies (P<.01). Only one patient in the MRI-positive group had deficiency that required hormone replacement, in contrast six patients in the MRI-negative group had deficiencies that were of clinical significance and which required hormone replacement. SUMMARY: This study shows a clinically significant incidence of anterior pituitary hormone deficiency in patients with idiopathic hyperprolactinaemia. The authors recommend that dynamic pituitary assessment should be considered routinely in this patient group. A prospective study would be required to assess the underlying cause for these abnormalities, as they suggest a nontumour pan-pituitary process.

Abnormal plasma sodium concentrations in patients treated with desmopressin for cranial diabetes insipidus: results of a long-term retrospective study.

CONTEXT AND OBJECTIVE: Patients with cranial diabetes insipidus (CDI) are at risk of developing both hypernatraemia and hyponatraemia, due to the condition itself or secondary to treatment with vasopressin-analogues or during administration of i.v. fluids. We aimed to assess the frequency and impact of dysnatraemias in the inpatient (INPT) and outpatient (OPT) setting in desmopressin-treated CDI, comparing those with normal thirst with those with abnormal thirst. DESIGN: The study included 192 patients with cranial diabetes, who were identified from the Beaumont Pituitary Database, a tertiary referral centre. Retrospective case note audit was performed and the clinical and biochemical information of 147 patients with CDI were available for analysis. RESULTS: A total of 4142 plasma sodium measurements for 137 patients with normal thirst, and 385 plasma sodium measurements for ten patients with abnormal thirst were analysed. In those with normal thirst, the most common OPT abnormality was mild hyponatraemia (pNa(+) 131-134  mmol/l) in 27%, while 14.6% had more significant hyponatraemia (pNa(+) ≤130  mmol/l). Of those patients with normal thirst, 5.8% were admitted due to complications directly related to hyponatraemia. Compared with patients with normal thirst, those with abnormal thirst were more likely to develop significant OPT hypernatraemia (20% vs 1.4%, P=0.02) and significant INPT hyponatraemia (50% vs 11.1%, P 0.02). CONCLUSION: OPT management of CDI is complicated by a significant incidence of hyponatraemia. In contrast, OPT hypernatraemia is almost exclusively a complication seen in adipsic CDI, who also had more frequent INPT hyponatraemia. CDI associated with thirst disorder requires increased physician attention and patient awareness of potential complications.