Continuous renal replacement therapy in a neonate with methylmalonic acidemia and severe hyperammonemia: A case...

Methylmalonic acidemia (MMA) is a rare disease that is often misdiagnosed and overlooked. Metabolic acidosis and severe hyperammonemia are severe morbidities of MMA that demand immediate treatment.

Here, we describe an MMA neonate with severe hyperammonemia and acidosis that was successfully rescued by continuous renal replacement therapy. A 6-day-old male neonate, with a gestational age of 39 + 3 weeks and a birth weight of 2880 g, was admitted to the emergency with the symptoms of "cyanosis of the face and coma for 2 hours." The infant was suffering from hypoglycemia, hypocalcemia, severe hyperammonemia, and severe metabolic acidosis. After admission, the blood ammonia continued to rise, and continuous renal replacement therapy was promptly administered until the patient gradually regained consciousness. Blood tandem mass spectrometry and profiles revealed that methylmalonic acid and methyl citrate levels were significantly enhanced. Two heterozygous mutations were detected in the MUT gene, confirming the diagnosis of methylmalonic acidemia mut.

The patient's symptoms gradually improved after receiving vitamin B12, l-carnitine, and specialized milk feeding. The patient was successfully discharged from the hospital after 41 days.