Specificity of late-night salivary cortisol measured by automated electrochemiluminescence immunoassay for Cushing's disease in an obese population.

PURPOSE: Data about the specificity of late-night salivary cortisol (LNSC) in obese subjects are still conflicting. Therefore, with this study, we aimed to evaluate the specificity of LNSC measurement in an obese cohort with or without type 2 diabetes mellitus (T2DM) using an automated electrochemiluminescence immunoassay (ECLIA). METHODS: A total number of 157 patients involving 40 healthy subjects (HS) with BMI < 25 kg/m2, 83 obese subjects (OS) with BMI ≥ 35 kg/m2, and 34 histopathologically proven Cushing's disease (CD) were included. All patients underwent LNSC testing. Salivary cortisol was measured at 11 p.m. for all groups using an ECLIA. Reference range was established using values of LNSCs of HS and ROC curves were used to determine diagnostic cutoffs. RESULTS: In the HS group, mean LNSC was 4.7 nmol/l (SD ± 3.1), while the OS group had a mean value of 10.9 nmol/l (SD ± 7.5) and the CD group of 19.9 nmol/l (SD ± 15.4). All groups differed significantly (p < 0.001). The ROC analysis of CD against HS alone showed a sensitivity of 85.3% and a specificity of 87.5% with a cut-off value of 8.3 nmol/l. The ROC analysis between OS and CD showed a maximum sensitivity of 67.6% and specificity of 78.3% for a cut-off value of 12.3 nmol/l. Taken both (HS and OS) groups together against the CD group, ROC analysis showed a maximum sensitivity of 67.6% and specificity of 85.4% for a cut-off value of 12.3 nmol/l. No correlation was found between BMI, T2DM, and LNSC for all groups. CONCLUSIONS: In our obese cohort, we found that LNSC assayed by ECLIA had a low specificity in the diagnosis of CD.

Hyponatremia after trans-sphenoidal surgery.

Fluid and electrolyte imbalances are the most frequent complications following pituitary surgery. Among the several patterns of occurrence, hyponatremia can occur in an isolated fashion or as part of a bi- or triphasic pattern. The frequency of hyponatremia after trans-sphenoidal surgery is between 2% and 25%, according to the literature. However, these numbers are probably underestimating the real prevalence, since mild hyponatremia does not lead to symptoms and measurement of sodium level. No association has been described between entity of the pituitary tumor or tumor size and hyponatremia. Therefore no predictors exist to determine patients with a higher risk for electrolyte imbalances after surgery. However, since delayed hyponatremia occurs mainly around the 8-10th day after surgery, routine measurement of sodium should be recommended on the day of hospital dismission. In case of a symptomatic hyponatremia, insufficiency of the corticotrophe pituitary function as the leading differential diagnosis needs to be ruled out. If the patient is euvoleme, pretest probability of syndrome of inadequate antidiuretic hormone production (SIADH) is very high and therapy may be started according to this. In case of SIADH, therapeutic options include fluid restriction or vaptane therapy. Only in severe cases infusion of hypertonic saline is appropriate. Usually SIADH following pituitary surgery is a self-limiting condition and will cease within 2-5 days.

Long-term follow-up and quality of life in patients with intracranial germinoma.

Intracranial germinomas are fairly rare tumors occurring mostly in children or young adults with a comparatively good prognosis. Radiation is the preferred treatment of choice for this diagnosis. It has been thoroughly studied to what extent radiation doses and fields can be limited in order to avoid side effects in these young patients. The role of chemotherapy remains unclear, whereas surgery is limited to biopsy for proof of histology. Regarding the good overall survival rate, quality of life is a significant aspect to consider in these patients. We present a single institution analysis of patients with intracranial germinoma and analyze the long-term outcome with special regard to quality of life. Thirty-three patients with intracranial germinomas were analyzed by chart review, telephone interview, and neurological assessment. Additionally, a survey on quality of life was performed. The 10-year overall survival rate was 82.1 % at a mean follow-up of 141 (22-306) months. Three quarters (76 %) of the patients reached a favorable neurological outcome on the Modified Rankin Scale (mRS 0-2). However, the self-reported quality of life was significantly worse in germinoma patients compared with a healthy control group (p < 0.001). Surgical resection of the tumor led to no improvement regarding overall survival, neurological outcome, and quality of life. In terms of cognitive functioning, patients with tumor resection were significantly more impaired than biopsied patients (p = 0.04). Although germinomas are efficiently treatable tumors, the restrictions in quality of life in these often young patients are considerable, including financial difficulties. There seems no justification for tumor resection in newly diagnosed cases suspicious for germinoma as the cognitive outcome is worse than in biopsied patients, and there is no effect on overall survival.