Background: Since many acutely admitted older adults display signs of dehydration, treatment using balanced crystalloids is an important part of medical care. Additionally, many of these patients suffer from chronic malnutrition. We speculated that the early addition of glucose might ameliorate the hospital-related drop of caloric intake and modify their catabolic status. Methods: We included patients 78 years and older, admitted acutely for non-traumatic illnesses. The patients were randomized into either receiving balanced crystalloid (PlasmaLyte; group P) or balanced crystalloid enriched with 100 g of glucose per liter (group G). The information about fluid balance and levels of minerals were collected longitudinally. Results: In the G group, a significantly higher proportion of patients developed signs of refeeding syndrome, i.e., drops in phosphates, potassium and/or magnesium when compared to group P (83.3 vs. 16.7%, p < 0.01). The drop in phosphate levels was the most pronounced. The urinalysis showed no differences in the levels of these minerals in the urine, suggesting their uptake into the cells. There were no differences in the in-hospital mortality or in the 1-year mortality. Conclusion: The short-term administration of balanced crystalloids with glucose induced an anabolic shift of electrolytes in acutely admitted older adults.

Metformin-associated lactic acidosis (MALA) involves mitochondrial Complex I inhibition, traditionally diagnosed via indirect markers. We present platelet high-resolution respirometry (HRR) as a novel “liquid biopsy” to directly quantify metformin-induced systemic bioenergetic lesions. A 65-year-old diabetic male presented with severe lactic acidosis, acute kidney injury, and profound hypoglycemia after intentionally overdosing on metformin (120 g), dapagliflozin (600 mg), and insulin glargine (300 U). While hemodialysis cleared plasma metformin and resolved the acidosis, refractory hypoglycemia required high-dose IV glucose for over six days. Day 2 platelet HRR revealed severe Complex I inhibition despite significantly decreased plasma metformin, indicating a profound “toxicodynamic lag.” Mitochondrial bioenergetics recovered by Day 7, reflecting natural platelet turnover. The protracted hypoglycemia was driven by a synergistic triad: metformin-inhibited gluconeogenesis, insulin glargine’s prolonged depot effect, and dapagliflozin-induced persistent renal glucose wasting. Platelet HRR has the potential to be a clinically applicable tool to reveal the “hidden” cellular phase of metformin toxicity missed by standard biomarkers. Furthermore, clinicians must anticipate severe, protracted hypoglycemia in mixed overdoses involving SGLT2 inhibitors.