Right frontal lobe encephalomalacia in an adult propionic acidemia patient with neuropsychiatric manifestations

We describe a 29 year old patient with propionic acidemia presentingwith a sudden onset of neuropsychiatric symptoms. The diagnosis of propionic acidemia wasmade by a fibroblast enzyme assay at the age of 5 weeks during an episode of coma and acidosis. He had several episodes of metabolic decompensation in early childhood leading to global developmental delays. The patient was lost to follow up after 8 years of age. He reestablished care at 26 years of age. No abnormal behavior was noted at that time. He was noted to have a diminished tone of extremities and was reported to use the left upper extremity less frequently. He was living in a group home and taking carnitine supplements. He was reportedly on a low protein diet supervised by a nutritionist at the group home. After reestablishing care, his carnitine supplementation and diet were optimized. Subsequently his clinical examination was unchanged and his laboratory parameters (plasma amino acids, urine organic acids, plasma free and total carnitine, and plasma acylcarnitine profile) suggested goodmetabolic control. The patient had a sudden onset of abnormal behavior at 28 years and 9 months of age. It consisted of outbursts of aggressive behavior. He was noted to be violent andwould hit his caregivers and other residents at the group home. He was mostly confined to himself and lost interest in things he used to like such as gardening. He had frequent spells of crying for no apparent reason. He would wake up early in the morning and enter other residents' rooms and wake them up too. He also developed obsessive behaviors such as playing with water, putting shoes in grocery bags, playing with toilet paper, collecting towels, etc. He would repetitively ask the same question. He appeared anxious at his new baseline. He had poor sleep. His appetite diminished and he had significantweight loss. Hewas hospitalized and evaluated formetabolic decompensation during an episode of behavioral outburst. His evaluation was unremarkable. He was reported to have staring spells but EEGwas not suggestive of seizure. During an outpatient visit at themetabolic clinic, he was found to have a diminished tone and brisk reflexes in all extremities but there were worsening contractures and diminished movement of the left upper and lower extremities which were new findings. Hence, MRI of the brain was obtained which showed right frontal lobe encephalomalacia (Fig. 1). The reason for the current behavioral abnormality is unclear. There is no evidence of acute or chronic metabolic decompensation. The