Endocrine Abstracts

Introduction: Metformin is recommended as the first-line pharmacological agent for patients with diabetes mellitus type 2. Its most feared adverse effect is the metformin-associated lactic acidosis (MALA), which appears rarely, but the mortality risk reaches almost 50 percent. This case report describes a story of a severely metformin intoxicated patient with several rare complications and uneven outcome.

Case-report: A 74-year-old man was found at home, unconscious, spontaneously breathing, hypotensive and hypoglycemic. He was admitted to ICU on vasopressor treatment. Major laboratory findings were severe metabolic acidosis including severe hyperkalemia, hyperlactatemia (maximal level of 12 mmol/l), severe renal impairment (eGFR 5 ml/min/1.73m²), troponin T (84 ng/l), CRP (31 mg/l), leukocytosis (22×10⁹), anemia (80g/l), metformin level (34.2 ug/ml). Initially acute coronary syndrome, pulmonary embolism, acute sonographic pathology of the urological tract were excluded and renal replacement therapy (RRT) was necessary for suspect metformin intoxication. After stabilization, he was transferred to a standard internal ward. According to prior patients history, his regular medication was metformin 2 g/day and glimepiride 4mg/day. His last documented laboratory results were normal renal functions, normal blood count one year ago. After 14 days on RRT was the patient still anuric, so the postrenal obstruction was suspected. Ultrasound-guided percutaneous bilateral nephrostomies were inserted with a prompt effect and restoration of diuresis and reparation of renal functions. An X-ray pyelouretrography showed bilateral ureteral obstruction without concrement involvement. An abdominal contrast CT scan revealed a tumor suspect formation in colon ascendens. Via colonoscopy, a diagnosis of colorectal cancer was established and it explained the initial anemia, despite its laboratory findings typical for anemia of chronic diseases. A rare complication appeared, a late onset of heparin-induced thrombocytopenia (HIT), 16th day after initiation of heparin administration, for which the patient had to be anticoagulated with therapeutic doses of Fondaparinux for a HIT-associated deep vein thrombosis of the left leg and mild pulmonary subsegmental embolism. Even though there was no suspect liver metastasis on the CT scan, during the surgery a peritoneal carcinosis was found and so palliative ileotransversoanastomosis was done, concomitant oncological treatment was not planned. A bilateral postrenal extraluminal obstruction due to disseminated colorectal carcinoma was settled.

Conclusion: A case of quickly silently growing colorectal cancer of colon ascendens was described, which in one year resulted in bilateral postrenal obstruction, which led to chronic metformin overdose and sudden severe lactic acidosis.