Presentation
An 84-year-old woman was admitted to the ICU for sepsis and severe hyperglycemia. The patients had a medical history of type 2 diabetes mellitus (T2DM), hypertension, chronic kidney disease, dyslipidemia, and hypothyroidism .She was on oral antidiabetic agents [metformin (1.7 g/day), glimepiride (3 mg/day), and linagliptin (5 mg/day)]. Upon admission, she had extreme fatigue, epigastric discomfort, and tenderness at the left costovertebral angle. Bilateral lower extremity edema was also noted.

Examination and Investigations
Physical examination confirmed abdominal tenderness and edema. Chest X-ray showed small bilateral pleural effusions. Abdominal ultrasound demonstrated mild dilation of the left renal pelvis. A CT scan found bilateral nephropathy with no obstruction or acute abnormalities. The patient had severe hyperglycemia (>40 mmol/L), hyponatremia (116 mmol/L), and hyperkalemia (5.9 mmol/L). She also had raised inflammatory markers. Metformin-associated lactic acidosis was suspected because of renal dysfunction. However, her serum metformin levels were normal.

Diagnosis
The patient was diagnosed with sepsis secondary to a urinary tract infection and decompensated T2D. The initial presentation and metabolic derangement required close monitoring and intensive management.

Management
She was initiated on broad-spectrum antibiotics, crystalloid infusions, and continuous intravenous (IV) insulin therapy. There was a rapid reduction in the blood glucose levels to <10 mmol/L within nine hours, resulting in switching to subcutaneous insulin. However, her blood glucose spiked again above 20 mmol/L despite no caloric intake, necessitating the resumption of IV insulin. A pattern of sharp glycemic fluctuations emerged—rapid drops followed by unexpected spikes—even in the absence of food or glucose infusions. A new approach was implemented for glucose level stabilization: continuous IV glucose infusion was initiated alongside IV insulin therapy. Initially, she had higher glucose levels. However, careful dose adjustments resulted in reduced insulin requirements over the next 12 hours. The IV insulin was discontinued. The patient had stable blood glucose despite ongoing glucose infusion.

Follow-Up
With clinical improvement, the patient restarted oral feeding and was shifted on subcutaneous insulin regimen. She received diabetes education from a trained nurse and was discharged home in stable condition.