A 25-year-old woman presented with progressive apathy and disorientation, followed by acute-onset confusion that progressed to stupor. Physical examination revealed generalized reflex myoclonus to both tactile (Video 1, part 1) and visual stimuli (part 2). Hepatic and autoimmune workup was positive for transaminitis, hyperammonemia, and antimitochondrial and anti-smooth muscle antibodies (Table). The rest of her laboratory test results including chemistries were within normal limits. MRI of the brain was likewise unremarkable. EEG showed generalized slowing. She was diagnosed with autoimmune hepatitis-primary biliary cholangitis overlap syndrome1 with hepatic encephalopathy. She was treated with steroids with full resolution of her myoclonus (Video 1, part 3). Hepatic encephalopathy is usually associated with negative myoclonus (asterixis) rather than reflex myoclonus. Little is known about the mechanism of reflex myoclonus, although small studies suggest cortical and subcortical subtypes reflect the origin of electrical signals leading to the myoclonic jerks.2
The authors report no targeted funding.
The authors report no disclosures relevant to the manuscript. Go to Neurology.org/N for full disclosures.
The authors appreciate the help of Dr. Ninad Desai from St. Vincent’s Medical Center, Bridgeport, CT, USA, for interpretation of EEG during the photomyoclonic response recording.
- Received December 20, 2021.
- Accepted in final form March 29, 2022.
- © 2022 American Academy of Neurology