Severe lactic acidosis after re-exposure to linezolid in a person living with HIV and multidrug resistant tuberculosis: a case report

Linezolid-induced lactic acidosis is rare and portends a poor prognosis. The mechanism of toxicity may be related to inhibition of mitochondrial ribosomes. We present the first case in the literature of a patient with HIV and multidrug resistant tuberculosis with fatal lactic acidosis secondary to linezolid re-exposure. The index case relates to a 37-year-old lady with a background medical history of HIV, on fixed combination antiretroviral therapy. In addition, she had multidrug resistant pulmonary tuberculosis and was being treated on a salvage antituberculosis regimen containing linezolid. She presented with a 1-day history of backpain, nausea and vomiting. Clinically she was severely acidotic with a lactate of 12 mmol/L, which peaked at 19 mmol/L. A presumptive diagnosis of lactic acidosis was made based on the history and exclusion of other causes. The patient demised despite management in the intensive care unit with continuous veno-venous haemodialysis (CVVH) and mechanical ventilation. The diagnosis of linezolid-induced lactic acidosis requires a high index of suspicion and exclusion of other causes. In the absence of definitive treatment, early diagnosis, drug discontinuation and prompt supportive management including continuous veno-venous haemodiafiltration are key in helping to reduce the high mortality associated with this toxicity.