7643 Acute blindness due to Metformin associated lactic acidosis

Abstract Disclosure: K.N. Pereira: None. K. Desai: None. T. Khan: None. S. Yong: None. Metformin, one of the most commonly prescribed oral hypoglycemic agents, effectively lowers basal and postprandial blood glucose. However, Metformin carries a black box warning for lactic acidosis, which is more common in setting of liver and kidney dysfunction. With an incidence rate of ∼ 4.3 cases per 100,000 patient-years, Metformin associated lactic acidosis (MALA) can present with nausea, vomiting, diarrhea, encephalopathy, hypothermia, respiratory failure and hypotension. Blindness is a rarely reported outcome of MALA. We present a case of a 48 year old intellectually disabled female with a history of type 2 diabetes (on Metformin) who presented with progressive encephalopathy insetting of intractable nausea and vomiting with poor oral intake, since starting lisinopril & rosuvastatin for newly diagnosed hypertension and hyperlipidemia. She was encephalopathic, hypothermic, hypotensive, tachycardic and tachypneic. Labs were notable for leukocytosis, AKI, hyperkalemia, elevated anion gap metabolic acidosis with a lactate of 13.6 and elevated lipase. She also tested positive for Influenza A. CT head showed no acute intracranial abnormality. CT chest, abdomen & pelvis was concerning for aspiration, multifocal pneumonia or a combination of both as well as acute interstitial pancreatitis. She was admitted to the ICU for further management including hemodialysis. She continued to have improving but persistent lactic acidosis despite multiple dialysis sessions. On day 5 of ICU stay, with resolution of her encephalopathy, she reported new onset complete bilateral painless vision loss. General eye and neurologic exam was unrevealing except for sluggishly reactive pupils to light. MRI brain showed an new acute 2 mm lacunar infarct in the right temporal lobe. Neurology ruled out stroke as the cause for her vision loss. Emergent ophthalmology evaluation revealed no retinopathy, macular edema, acute glaucoma or thromboembolic event. The new onset vision loss was suspected to be due to MALA due to persistent metabolic disturbances. Some animal studies have shown that retinal horizontal cells are sensitive to low pH, resulting in interruption of signal transmission to the visual neurons and consequent blindness. The presence of factors like metformin metabolites may contribute to impaired function of retinal cells.On extensive literature review it was noted that only 5 cases of vision loss associated with MALA have been reported. However, in these cases, vision loss was transient and reversed following correction of acidosis with dialysis. Our case highlights a rare consequence of MALA, which can be irreversible and cause lifelong disability. Presentation: 6/1/2024