RESUMEN
Metformin is a widely prescribed, oral, anti-diabetic agent for the treatment of type 2 diabetes mellitus (DM2). While generally well-tolerated, metformin can accumulate in patients with acute kidney injury (AKI) or chronic kidney disease (CKD), leading to potentially life-threatening complications such as metformin-associated lactic acidosis (MALA). Severe hyperkalemia is a rare but serious manifestation of metformin toxicity. We report a case of a 74-year-old African American man with DM2, hypertension, and CKD stage 3a, who presented with nausea, vomiting, lethargy, and diarrhea. Laboratory findings revealed severe AKI with a creatinine level of 8 mg/dL (baseline 1.7 mg/dL) and a potassium level of 7.8 mEq/L. The patient developed refractory hyperkalemia requiring multiple interventions and eventually continuous renal replacement therapy. Further evaluation revealed metformin-induced severe lactic acidosis with a metformin level of 21 mcg/mL (therapeutic range <5 mcg/mL). This case highlights the importance of recognizing metformin toxicity as a potential cause of severe, refractory hyperkalemia and metabolic acidosis in patients with AKI or CKD. Early recognition and prompt discontinuation of metformin, along with appropriate management of electrolyte disturbances and metabolic derangements, are crucial in preventing life-threatening complications.
RESUMEN
Superior vena cava (SVC) syndrome is an unusual complication of pacemaker and implantable cardioverter-defibrillator implantation. It is believed to be due to SVC thrombosis with or without stenosis induced by endothelial disruption from repeated mechanical trauma by the leads. A 58-year-old man presented with gradual swelling of his face, neck, and upper extremities of 10 days duration. A pacemaker had been implanted for symptomatic bradycardia over 5 years ago. Venous Doppler and venogram revealed thrombosis and stenosis of the SVC. He was treated with multimodal therapy and was discharged with complete resolution of his symptoms.