Cinacalcet-Associated Resolution of Primary Hyperparathyroidism in a Patient With Normal Kidney Function.

Cinacalcet use is associated with risk of hypocalcemia; however, this risk has been mostly demonstrated in patients with chronic kidney disease. In this article, we describe a case of a 59-year-old male with primary hyperparathyroidism (PHPT), hypercalciuria, osteopenia, and normal kidney function who was started on cinacalcet for the management of recurrent hypercalcemia following prior unsuccessful parathyroidectomy. Within 6 months following cinacalcet commencement, he developed symptomatic and biochemical hypocalcemia requiring discontinuation of the medication and initiation of calcium supplementation. Over more than 3 years of follow-up, his calcium supplementation was gradually tapered off and then discontinued. He is presently eucalcemic and euparathyroid off calcium supplements while also demonstrating normalization of hypercalciuria and bone mineral density. These data indicate that our patient has experienced resolution of PHPT after brief exposure to cinacalcet. We recommend that low starting cinacalcet doses should be considered for treatment of hypercalcemia in patients with PHPT who underwent unsuccessful parathyroidectomy along with close clinical and biochemical follow-up.

Management of hyperglycemia during enteral and parenteral nutrition therapy.

Hyperglycemia is a frequent complication of enteral and parenteral nutrition in hospitalized patients. Extensive evidence from observational studies indicates that the development of hyperglycemia during parenteral and enteral nutrition is associated with an increased risk of death and infectious complications. There are no specific guidelines recommending glycemic targets and effective strategies for the management of hyperglycemia during specialized nutritional support. Managing hyperglycemia in these patients should include optimization of carbohydrate content and administration of intravenous or subcutaneous insulin therapy. The administration of continuous insulin infusion and insulin addition to nutrition bag are efficient approaches to control hyperglycemia during parenteral nutrition. Subcutaneous administration of long-acting insulin with scheduled or corrective doses of short-acting insulin is superior to the sliding scale insulin strategy in patients receiving enteral feedings. Randomized controlled studies are needed to evaluate safe and effective therapeutic strategies for the management of hyperglycemia in patients receiving nutritional support.

Vascular effects of intravenous intralipid and dextrose infusions in obese subjects.

Hyperglycemia and elevated free fatty acids (FFA) are implicated in the development of endothelial dysfunction. Infusion of soy-bean oil-based lipid emulsion (Intralipid®) increases FFA levels and results in elevation of blood pressure (BP) and endothelial dysfunction in obese healthy subjects. The effects of combined hyperglycemia and high FFA on BP, endothelial function and carbohydrate metabolism are not known. Twelve obese healthy subjects received four random, 8-h IV infusions of saline, Intralipid 40 mL/h, Dextrose 10% 40 mL/h, or combined Intralipid and dextrose. Plasma levels of FFA increased by 1.03±0.34 mmol/L (p=0.009) after Intralipid, but FFAs remained unchanged during saline, dextrose, and combined Intralipid and dextrose infusion. Plasma glucose and insulin concentrations significantly increased after dextrose and combined Intralipid and dextrose (all, p<0.05) and were not different from baseline during saline and lipid infusion. Intralipid increased systolic BP by 12±9 mmHg (p<0.001) and diastolic BP by 5±6 mmHg (p=0.022),and decreased flow-mediated dilatation (FMD) from baseline by 3.2%±1.4% (p<0.001). Saline and dextrose infusion had neutral effects on BP and FMD. The co-administration of lipid and dextrose decreased FMD by 2.4%±2.1% (p=0.002) from baseline, but did not significantly increase systolic or diastolic BP. Short-term Intralipid infusion significantly increased FFA and BP; in contrast, FFA and BP were unchanged during combined infusion of Intralipid and dextrose. Combined Intralipid and dextrose infusion resulted in endothelial dysfunction similar to Intralipid alone.

Medical nutrition therapy in hospitalized patients with diabetes.

Medical nutrition therapy (MNT) plays an important role in management of hyperglycemia in hospitalized patients with diabetes mellitus. The goals of inpatient MNT are to optimize glycemic control, to provide adequate calories to meet metabolic demands, and to create a discharge plan for follow-up care. All patients with and without diabetes should undergo nutrition assessment on admission with subsequent implementation of physiologically sound caloric support. The use of a consistent carbohydrate diabetes meal-planning system has been shown to be effective in facilitating glycemic control in hospitalized patients with diabetes. This system is based on the total amount of carbohydrate offered rather than on specific calorie content at each meal, which facilitates matching the prandial insulin dose to the amount of carbohydrate consumed. In this article, we discuss general guidelines for the implementation of appropriate MNT in hospitalized patients with diabetes.

Substitution of standard soybean oil with olive oil-based lipid emulsion in parenteral nutrition: comparison of vascular, metabolic, and inflammatory effects.

CONTEXT: Soybean oil-based lipid emulsions are the only Food and Drug Administration-approved lipid formulation for clinical use in parenteral nutrition (PN). Recently concerns with its use have been raised due to the proinflammatory effects that may lead to increased complications because they are rich in ω-6 polyunsaturated fatty acids. METHODS: This was a prospective, randomized, controlled, crossover study comparing the vascular, metabolic, immune, and inflammatory effects of 24-h infusion of PN containing soybean oil-based lipid emulsion (Intralipid), olive oil-based (ClinOleic), lipid free, and normal saline in 12 healthy subjects. RESULTS: Soybean oil-PN increased systolic blood pressure compared with olive oil-PN (P < 0.05). Soybean oil PN reduced brachial artery flow-mediated dilatation from baseline (-23% at 4 h and -25% at 24 h, both P < 0.01); in contrast, olive oil PN, lipid free PN, and saline did not change either systolic blood pressure or flow-mediated dilatation. Compared with saline, soybean oil PN, olive oil PN, and lipid free PN similarly increased glucose and insulin concentrations during infusion (P < 0.05). There were no significant changes in plasma free fatty acids, lipid profile, inflammatory and oxidative stress markers, immune function parameters, or sympathetic activity between soybean oil- and olive oil-based lipid emulsions. CONCLUSION: The 24-h infusion of PN containing soybean oil-based lipid emulsion increased blood pressure and impaired endothelial function compared with PN containing olive oil-based lipid emulsion and lipid-free PN in healthy subjects. These vascular changes may have significant implications in worsening outcome in subjects receiving nutrition support. Randomized controlled trials with relevant clinical outcome measures are needed in patients receiving PN with olive oil-based and soybean oil-based lipid emulsions.

Effects of oral and intravenous fat load on blood pressure, endothelial function, sympathetic activity, and oxidative stress in obese healthy subjects.

We compared the effects of high and low oral and intravenous (iv) fat load on blood pressure (BP), endothelial function, autonomic nervous system, and oxidative stress in obese healthy subjects. Thirteen obese subjects randomly received five 8-h infusions of iv saline, 20 (32 g, low iv fat) or 40 ml/h intralipid (64 g, high iv fat), and oral fat load at 32 (low oral) or 64 g (high oral). Systolic BP increased by 14 ± 10 (P = 0.007) and 12 ± 9 mmHg (P = 0.007) after low and high iv lipid infusions and by 13 ± 17 (P = 0.045) and 11 ± 11 mmHg (P = 0.040) after low and high oral fat loads, respectively. The baseline flow-mediated dilation was 9.4%, and it decreased by 3.8 ± 2.1 (P = 0.002) and 4.1 ± 3.1% (P < 0.001) after low and high iv lipid infusion and by 3.8 ± 1.8 (P = 0.002) and 5.0 ± 2.5% (P < 0.001) after low and high oral fat load, respectively. Oral and iv fat load stimulated oxidative stress, increased heart rate, and decreased R-R interval variability. Acute iv fat load decreased blood glucose by 6-10 mg/dl (P < 0.05) without changes in insulin concentration, whereas oral fat increased plasma insulin by 3.7-4.0 µU/ml (P < 0.01) without glycemic variations. Intravenous saline and both oral and iv fat load reduced leptin concentration from baseline (P < 0.01). In conclusion, acute fat load administered orally or intravenously significantly increased blood pressure, altered endothelial function, and activated sympathetic nervous system by mechanisms not likely depending on changes in leptin, glucose, and insulin levels in obese healthy subjects. Thus, fat load, independent of its source, has deleterious hemodynamic effects in obese subjects.