Clinical Reasoning: Progressive cognitive decline, cerebellar ataxia, recurrent myoclonus, and epilepsy

Abstract

Section 1A 23-year-old woman was admitted to our department due to recurrent attacks of myoclonus and generalized tonic-clonic seizures, progressive intellectual disability, and gait instability. Her family history was unremarkable. The patient's growth and developmental milestones in childhood were normal. At the age of 12 years, she initially complained of lower limb fatigue and slow running. One year later, she began to exhibit a progressive decline in memory and understanding. She subsequently became introverted. At 15 years of age, her cognitive decline aggravated and bradykinesia and upper limb motor tremor appeared and she had slurred speech. At the age of 18, she had her first generalized tonic-clonic seizure (GTCS) during sleep. Shortly thereafter, myoclonus jerks appeared. Since then, she has experienced recurrent GTCS attacks and myoclonic jerking. Levetiracetam and clonazepam were given, but the seizures and myoclonic jerking remained poorly controlled. At the age of 22 years, she was no longer able to control body balance and often fell while walking and could not perform fine movements such as writing. Her vision and hearing were not impaired. Council criteria) was detected in all 4 limbs. Muscle tone was decreased, but deep reflexes were exaggerated and a positive bilateral Babinski sign was noticed. The patient exhibited dysmetria on the finger-to-nose test, moderate limb ataxia, and a prominent instability of gait. The gait was wide-based, hypokinetic, and ataxic, with difficulty turning, and the arm swing was significant reduced. Myoclonic jerking in the trunk and limbs could occasionally be noted. Visual acuity and hearing test results were normal. Corneal Kaiser-Fleischer ring was not detected by slitlamp examination. Cherry-red spot and macular degeneration were not found on fundus examination.