Sequential MRI of the brain in a patient with Leigh syndrome revealed extensive changes and the development of posterior reversible encephalopathy syndrome

The majority of Leigh syndrome cases exhibit fulminant clinical courses, and magnetic resonance imaging (MRI) typically reveals evolutionary changes. We present a case of Leigh syndrome in which MRI of the brain revealed extensive changes along with the development of posterior reversible encephalopathy syndrome (PRES). An 8-year-old Japanese girl presented with gait disturbance. MRI revealed high-intensity areas in the bilateral basal ganglia and the ventral midbrain in T2-weighted images (T2WIs) and fluid attenuated inversion recovery (FLAIR). We identified the mitochondrial DNA homozygous mutation 9176T>C. The patient gradually recovered. One month after symptom onset, she developed respiratory and circulatory failure accompanied by lactic acidosis and disturbances of consciousness. A repeat MRI did not reveal any new lesions. Subsequently, 1 month later, she presented with disturbances of consciousness, headache, and vision disturbances. Her blood pressure was 210/140 mmHg; MRI revealed many spotty high-intensity areas, predominantly located in the parietal and occipital lobes in T2WIs and FLAIR. She was treated with hypotensive drugs and gradually recovered with improved MRI findings. This episode was diagnosed as PRES. This case revealed extensive changes in MRI findings of the brain, as well as disturbances of consciousness due to respiratory and circulatory failure and PRES. Sequential brain MRI is useful for the evaluation of patients with Leigh syndrome and for the detection of unexpected complications, such as PRES.