Maintenance vitamin D3 dosage requirements in Chinese women with post menopausal osteoporosis living in the tropics.

BACKGROUND AND OBJECTIVES: Vitamin D3 (cholecalciferol) dose required to maintain sufficiency in non- Caucasian women with postmenopausal osteoporosis (PMO) inthe tropics has not been well studied. Some guidelines mandate 800-1000 IU vitamin D/day but the Endocrine Society (US) advocates 1500-2000 IU/day to maintain 25-hydroxyvitamin-D (25(OH)D) concentration at >75 nmol/L. We aimed to establish oral cholecalciferol dose required to maintain 25(OH)D concentration at >75 nmol/L in PMO Chinese Malaysian women, postulating lower dose requirements amongst light-skinned subjects in the tropics. METHODS AND STUDY DESIGN: 90 Chinese Malaysian PMO women in Kuala Lumpur, Malaysia (2°30'N) with baseline serum 25(OH)D levels >=50 nmol/L were recruited. Prior vitamin D supplements were discontinued and subjects randomized to oral cholecalciferol 25,000 IU/4-weekly (Group-A) or 50,000 IU/4-weekly (Group- B) for 16 weeks, administered under direct observation. Serum 25(OH)D, PTH, serum/urinary calcium were measured at baseline, 8 and 16 weeks. RESULTS: Baseline characteristics, including osteoporosis severity, sun exposure (~3 hours/week), and serum 25(OH)D did not differ between treatment arms. After 16 weeks, 91% of women sufficient at baseline, remained sufficient on 25,000 IU/4-weekly compared with 97% on 50,000 IU/4-weekly with mean serum 25(OH)D 108.1±20.4 and 114.7±18.4 SD nmol/L respectively (p=0.273). At trial's end, 39% and 80% of insufficient women at baseline attained sufficiency in Group A and Group B (p=0.057). Neither dose was associated with hyperparathyroidism or toxicity. CONCLUSIONS: Despite pretrial vitamin D supplementation and adequate sun exposure, 25.6% Chinese Malaysian PMO women were vitamin D insufficient indicating sunshine alone cannot ensure sufficiency in the tropics. Both ~900 IU/day and ~1800 IU/day cholecalciferol can safely maintain vitamin D sufficiency in >90% of Chinese Malaysian PMO women. Higher doses are required with baseline concentration <75 nmol/L.

Hypothalamic germinoma masquerading as superior mesenteric artery (SMA) syndrome.

OBJECTIVE: To report a case of superior mesenteric artery (SMA) syndrome secondary to hypothalamic germinoma. METHODS: We describe the clinical presentation, diagnostic work-up, management, and clinical course of a patient admitted with SMA syndrome who was subsequently found to have a hypothalamic germinoma. RESULTS: An adolescent boy was admitted to the surgical ward with progressive weight loss over a 2 year period and postprandial vomiting. He was diagnosed with SMA syndrome based on evidence of proximal duodenal dilatation, extrinsic compression of the distal duodenum, and a narrowed aortomesenteric angle (16°). Investigations performed to exclude thyrotoxicosis unexpectedly revealed secondary hypothyroidism and further evaluation demonstrated evidence of pan-hypopituitarism. Psychiatric evaluation excluded anorexia nervosa and bulimia. Magnetic resonance imaging (MRI) of the brain revealed a heterogeneously enhancing hypothalamic lesion, but a normal pituitary gland. Hormone replacement with hydrocortisone, desmopressin, testosterone, and thyroxine resulted in weight gain and resolution of gastrointestinal symptoms. A transventricular endoscopic biopsy subsequently confirmed a hypothalamic germinoma and he was referred to an oncologist. CONCLUSION: SMA syndrome secondary to severe weight loss is an uncommon cause of upper gastrointestinal obstruction. While there have been reports of poorly controlled diabetes mellitus and thyrotoxicosis manifesting as SMA syndrome, there are no published reports to date of SMA syndrome secondary to hypothalamic/pituitary disease. Management of SMA syndrome is conservative, as symptoms of intestinal obstruction resolve with weight gain following treatment of the underlying cause. Awareness of this uncommon presentation of endocrine cachexia/hypothalamic disease will prevent unnecessary laparotomies and a misdiagnosis of an eating disorder.