Cognitive, neurophysiologic and metabolic sequelae of previous hypoglycemic coma revealed by hyperinsulinemic-hypoglycemic clamp in type 1 diabetic patients.

To examine the relationship between electroencephalographic (EEG) activity and hypoglycemia unawareness, we investigated early parameters of vigilance and awareness of various symptom categories in response to hypoglycemia in intensively treated type 1 diabetic (T1DM) patients with different degrees of hypoglycemia unawareness. Hypoglycemia was induced with a hyperinsulinemic-hypoglycemic clamp in six T1DM patients with a history of hypoglycemia unawareness previous severe hypoglycemic coma (SH) and in six T1DM patients without (C) history of hypoglycemia unawareness previous severe hypoglycemic coma. Cognitive function tests (four choice reaction time), counterregulatory responses (adrenaline), and symptomatic responses were evaluated at euglycemia (90 mg/dl) and during step-wise plasma glucose reduction (68, 58 and 49 mg/dl). EEG activity was recorded continuously throughout the study and analyzed by spectral analysis. Cognitive function deteriorated significantly at a glucose threshold of 55 ± 1 mg/dl in both groups (p = ns) during hypoglycemia, while the glucose threshold for autonomic symptoms was significantly lower in SH patients than in C patients (49 ± 1 vs. 54 ± 1 mg/dl, p < 0.05, respectively). In SH patients, eye-closed resting EEG showed a correlation between the mean dominance frequency and plasma glucose (r = 0.62, p < 0.001). Theta relative power increased during controlled hypoglycemia compared to euglycemia (21.6 ± 6 vs. 15.5 ± 3% Hz p < 0.05) and was higher than in the C group (21.6 ± 6 vs. 13.8 ± 3%, p < 0.03). The cognitive task beta activity was lower in the SH group than in the C group (14.8 ± 3 Hz, vs. 22.6 ± 4 vs. p < 0.03). Controlled hypoglycemia elicits cognitive dysfunction in both C and SH patients; however, significant EEG alterations during hypoglycemia were detected mainly in patients with a history of hypoglycemia unawareness and previous severe hypoglycemic coma. These data suggest that prior episodes of hypoglycemic coma modulate brain electric activity.

Two cases of statin-induced rhabdomyolysis associated with mononeuropathy.

HMG-CoA reductase inhibitors (statins) are highly effective drugs for prevention of cardiovascular events in high-risk patients. Due to the widespread prescription of these agents, special attention should be given to their rare adverse effects when these may have severe outcomes. Here, we report two cases of localized rhabdomyolysis associated with mononeuropathy in patients taking statins and suggest possible explanations for this uncommon association. Close monitoring for myopathic/neuropathic events is warranted in high-risk patients with pre-existing neuropathies who are taking statins.

Continuous glucose monitoring in conditions other than diabetes.

BACKGROUND: The development of new systems for continuous glucose monitoring has recently increased the interest for their potential applications among physicians involved in diabetes care. One of the most common applications of such devices is the identification of hypoglycaemic events in insulin-treated diabetic patients (particularly during the night) and the evaluation of the full daily glucose excursions. METHODS: Among commercially available glucose sensors, the Glucoday system has been utilized for practical clinical application in the last two years. One of the most important features of this device is the accuracy in monitoring interstitial glucose values, specifically in the hypoglycaemic range. This feature is clinically relevant when applied in the clinical setting of patients with type 1 diabetes mellitus. The ability to monitor glucose continuously could be indeed a useful tool for the study of hypoglycaemic conditions other than diabetes. RESULTS: In patients with hyperinsulinaemic hypoglycaemia, recurrent episodes of asymptomatic hypoglycaemia are common, and in patients with glycogen storage diseases, avoidance of recurrent and prolonged hypoglycaemic episodes usually require frequent determinations by mean of home blood glucose monitoring. CONCLUSIONS: Experimental preliminary evidences suggest that this new technology could be applied in the clinical setting to help the physician to identify mainly nocturnal hypoglycaemic events, otherwise not revealed by traditional self blood-glucose monitoring, even in those patients who are not treated by conventional insulin therapy.

Continuous subcutaneous glucose monitoring in diabetic patients: a multicenter analysis.

OBJECTIVE: To evaluate the accuracy of a new subcutaneous glucose sensor (Glucoday; A. Menarini Diagnostics) compared with venous blood glucose measurement in type 1 and type 2 diabetic patients. RESEARCH DESIGN: A multicenter study was performed in 70 diabetic patients. A microdialysis fiber was inserted subcutaneously into the periumbelical region and perfused with a buffer solution. Glucose concentrations in the dialysate were then measured every 3 min by the glucose sensor over a 24-h period, during which nine venous blood samples were also collected throughout the day. RESULTS: Both the insertion of the fiber and the wearing of the device were well tolerated by the patients. Subcutaneous glucose levels were well correlated with venous glucose measurements (r = 0.9, P < 0.001) over a wide range (40-400 mg/dl) for up to 24 h, with a single-point calibration. An analysis of 381 data pairs showed a linear relationship between the GlucoDay and serial venous blood glucose levels, and 97% of the data fell in the A and B regions of the error grid analysis. Percentage bias between the GlucoDay and the blood venous levels was -2.0% in the hypoglycemic range (<70 mg/dl), 6.9% in the euglycemic range (70-180 mg/dl), and 11.2% in the hyperglycemic range (>180 mg/dl). CONCLUSIONS: The GlucoDay system demonstrated high reliability and reported values that closely agreed with venous blood glucose measurements. The system was well tolerated and thus constitutes a relatively easy method to monitor glucose excursions in diabetic patients.