A 50-year-old Caucasian woman was admitted to our hospital with intermittent diarrhoea, emesis and increasingly brown-coloured skin, mainly the in light-exposed areas, after biliopancreatic diversion for obesity treatment. Differential diagnoses such as adrenal insufficiency were ruled out, but biochemical analysis demonstrated unusual high pyridoxine serum levels (vitamin B6). History revealed the intake of 300 mg of vitamin B6 per day over 6 months as described by her general practitioner. All symptoms disappeared after the discontinuation of vitamin B6 supplementation. Importantly, in contrast to many other vitamins and supplements, there is no evidence in the literature of the occurrence of vitamin B6 deficiency after bariatric surgery. Therefore, supplementation of vitamins and supplements in bariatric patients has to be carefully considered according to the existing clinical guidelines, as uncritical oversupplementation of micronutrients might result in intoxication and serious illness as presented here.
In this study, we compared the 2 mg dexamethasone suppression test (DST) with the gold-standard 1 mg DST in obese patients in order to reduce the false-positive rate for Cushing's syndrome (CS). The primary endpoint was the comparison of serum cortisol levels after 1 mg versus 2 mg DST in patients with a BMI >30 kg/m and at least one additional feature of the metabolic syndrome. Secondary endpoints were comparison of salivary cortisol and ACTH levels, respectively. Fifty-four obese patients were included. Median serum cortisol levels after 1 mg DST and 2 mg DST were similar [28 nmol/l (20; 36) vs. 28 nmol/l (20; 38), p=0.53]. Salivary cortisol was 8.2 nmol/l (4.7; 11.7) after the 1 mg DST vs. 6.7 nmol/l (4.2; 9.5) after the 2 mg test, p=0.09. ACTH levels were higher after the 1 mg DST compared to the 2 mg DST [10.0 pg/ml (7.6; 10.7) vs. 5.0 pg/ml (5.0; 5.1), p<0.0001]. The false positive rate after the 1 mg DST was 14.8% (n=8) and was reduced to 11.1% (n=6) after the 2 mg DST. All non-suppressors (n=8) had type 2 diabetes and most of them took a medication interacting with cytochrome P450 3A4 (CYP3A4). In individuals with obesity, the 2 mg DST was not superior to the 1 mg DST in regard to serum cortisol levels. However, in some patients, particularly with poorly controlled diabetes or medication interacting with CYP3A4 and without adequate suppression after the 1 mg DST, the 2 mg DST might prove helpful to reduce the false-positive rate for CS. NCT02227420.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.