Recent in vitro studies suggest that lactate, rather than glucose, may be the preferred fuel for neuronal metabolism. The authors examined the effect of lactate on global brain glucose uptake in euglycemic human subjects using 18 fluoro-deoxyglucose (FDG) positron emission tomography (PET). Eight healthy men, aged 40 to 54 years, underwent a 60-minute FDG-PET scan on two occasions in random order. On one occasion, 6.72% sodium lactate was infused at a rate of 50 micro mol. kg-1. min-1 for 20 minutes and then reduced to 30 micro mol. kg-1. min-1; 1.4% sodium bicarbonate was infused as a control on the other occasion. Plasma glucose levels were not different between the two groups (5.3 +/- 0.23 and 5.3 +/- 0.24 mmol/L, P = 0.55). Plasma lactate was significantly elevated by lactate infusion (4.08 +/- 0.35 vs. 0.63 +/- 0.22 mmol/L, P < 0.0005. The whole-brain rate of glucose uptake was significantly reduced by approximately 17% during lactate infusion (0.195 +/- 0.022 vs. 0.234 +/- 0.020 micro mol. g-1. min-1, P = 0.001). The authors conclude that, in vivo in humans, circulating lactate is used by the brain at euglycemia, with sparing of glucose.

The effect of basal insulin on global and regional brain glucose uptake and metabolism in humans was studied using 18-fluorodeoxyglucose and positron emission tomography (FDG-PET). Eight healthy male volunteers aged 49.3 +/- 5.1 years were studied twice in random order. On each occasion, they received an infusion of 0.1 mg. kg(-1). min(-1) somatostatin to suppress endogenous insulin production. In one study 0.3 mU. kg(-1). min(-1) insulin was infused to replace basal circulating insulin levels, and in the other study a saline infusion was used as control. We sought stimulatory effects of basal insulin on brain glucose metabolism particularly in regions with deficiencies in the blood-brain barrier and high density of insulin receptors. Insulin levels were 27.07 +/- 1.3 mU/l with insulin replacement and 3.51 +/- 0.4 mU/l without (P = 0.001). Mean global rate of brain glucose utilization was 0.215 +/- 0.030 mmol. kg(-1). min(-1) without insulin and 0.245 +/- 0.021 mmol. kg(-1). min(-1) with insulin (P = 0.008, an average difference of 15.3 +/- 12.5%). Regional analysis using statistical parametric mapping showed that the effect of basal insulin was significantly less in the cerebellum (Z = 5.53, corrected P = 0.031). We conclude that basal insulin has a role in regulating global brain glucose uptake in humans, mostly marked in cortical areas.

Oral purgatives such as sodium phosphate and sodium picosulfate/magnesium citrate (Picolax) combinations are commonly used as a preparation step for colonoscopies in Ireland. These substances can occasionally cause significant electrolyte disturbances including hyponatraemia. Although this is a rare complication of undergoing a colonoscopy, if not treated promptly and appropriately, these electrolyte abnormalities can be associated with life threatening complications. We report cases of symptomatic hyponatraemia in three women aged 65-75 years, following ingestion of Picolax in preparation for a colonoscopy. All three patients had documented previously normal electrolytes and all three required hospital admission for management of their electrolyte disturbance. However, the clinical presentations were variable and depended upon the severity of the hyponatraemia. Patient 1 presented with nausea and vomiting 7 hours post Picolax ingestion. Plasma sodium was 124 mmol/l. She was diagnosed with mild symptomatic hyponatraemia, and treated with anti-emetics and slow intravenous infusion of 0.9% Saline. Patient 2 developed acute confusion 8 hours following ingestion of Picolax. Plasma sodium was 120 mmol/l and she was clinically dehydrated. She was also treated with intravenous 0.9% Saline. Patient 3 presented with seizures and reduced GCS, 48 hours post Picolax ingestion. Plasma sodium was 111 mmol/l. As she had severe life threatening hyponatraemia with seizures, she was treated with boluses of 3% hypertonic saline. It is recommended that cleansing agents should be used with caution in the elderly, patients with a low seizure threshold, patients with renal impairment, liver cirrhosis, heart failure, and patients on diuretics. These patients should have plasma sodium monitored pre-and post-colonoscopy to ensure early detection of hyponatraemia if present, and to initiate prompt and appropriate management to prevent the serious complications associated with hyponatraemia.

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Increased life expectancy in patients with cystic fibrosis (CF) has brought about novel challenges in their care. Cystic fibrosis-related diabetes (CFRD) and osteoporosis represent an increasing burden of disease in these patients as they get older. Furthermore, recent evidence suggests a link between dysglycaemia and loss in BMD in cystic fibrosis. We sought to determine predictors of low bone mineral density (BMD) in a cohort of patients attending the Cystic Fibrosis Unit, Beaumont Hospital, Dublin. In particular, we aimed to determine whether dysglycaemia is a significant risk factor.

Background• Dose Adjustment for Normal Eating (DAFNE) structured education programme is an effective tool in improving glycaemic control in patients with Type-1 diabetes while reducing the frequency of hypoglycemic episodes.• DAFNE however, does not solve all glucose related problems and patients often request or are recommended continuous subcutaneous insulin infusion (CSII) therapy post DAFNE. Results• 56% patients were female.• Mean Age was 40 ± 9.4 (mean±SD) years with a BMI of 26.6+4.5 kg/m 2.• Mean duration of Diabetes was 17.2±8.5 years.• Duration since completion of DAFNE at the time of study was 5.8±2.2 years.• Duration of CSII therapy was 4.0±2.2 years.• • The indication for commencement of CSII therapy was to improve overall glycemic control in 45% patients, impaired awareness of hypoglycaemia in 26% and patient preference, felt it would suit their lifestyle, in 23%.• HbA1c before commencement of CSII was 8.3%±1.07 (67.2±11.7 mmol/mol) compared to 7.9%±0.9 (62.8±9.9 mmol/mol) after 12 months of CSII therapy -p value=0.04. (Chart-2). Impact of DAFNE and subsequent CSII therapy on Glycaemic Control in Type-1 Diabetes Mellitus Conclusion• DAFNE is an effective education programme for patients with Type-1 Diabetes but may not improve glycaemic control in all.• Selected patients benefit from going on to CSII therapy post DAFNE and this can be associated with an improvement in their HbA1c. Objective• Out of our 370 DAFNE graduates, 46 have subsequently gone on to CSII therapy.• The aim of our audit was to examine glycaemic control of the 46 DAFNE graduates before and after they completed DAFNE & then before and after starting CSII therapy and their reason for starting CSII therapy. Methods• The data was collected using the hospital's electronic database (CELLMA and PIPE) and by contacting the patients via phone for further details.