Chorea-acanthocytosis: Challenges in early diagnosis and excellent treatment response to Deep Brain Stimulation (DBS) – a case report
Conference Paper/Poster - Sep 22, 2019
To describe diagnostic challenges and the response to DBS in a patient with genetically confirmed Chorea-acanthocytosis (ChAc).
At the age of 20 during his military service, our patient developed involuntary oral movements which produced smacking sounds. They were suppressible for short duration. The diagnosis of a primary tic disorder was made and treatment with aripiprazole was started without effect. After 6 months he started to have problems with eating. When we first saw him at that time he had oromandibular dystonia (feeding dystonia) and generalized chorea. Ankle reflexes were absent. In the diagnostic work-up CK levels were elevated, brain MRI showed iron deposition in the Globus pallidus and atrophy in the caudate nucleus and abdominal sonography showed hepatomegaly. Cognitive testing was unremarkable and there was no evidence for Wilson`s disease, mitochondriopathy, celiac disease or Nieman Pick Typ C. Remarkable is the fact that acanthocytes were not detected in 8x repetitive performed blood smears. Finally the diagnosis of ChAc could be done by proofing reduced chorein in the Western-blot and also by finding a homocygous mutation in the VPS13a gene. The clinical course was rapidly progressive. In particular the feeding dystonia was so prominent that a PEG tube had to be applied 2.5 years after the first symptoms. Medical treatment including anticholinergics, benzodiazepines and tetrabenazine and also botulinumtoxin injections were not successful. Hence, bilateral DBS in the Globus pallidus internus (Gpi) was performed 3 years after the first symptoms using Boston Scientific® system. The AIMS (Abnormal Involuntary Movement Scale) was reduced from 30 out of 40 points preoperative to 18 points two months later. Especially the feeding dystonia improved markedly so that the PEG tube was removed 5 months after the DBS surgery. But also generalized chorea was notably reduced. This positive effect was persistent over 2 years with an AIMS of 22 using the stimulation parameters as follows: Gpi left+right: monopolar, non-directional, second-distal contact, 4.0 mA, 90 µs, 130 Hz.
- Lack of acanthocytes in repetitive blood smears do not exclude the diagnosis of ChAc
- Patients with ChAc and drug-resistant hyperkinetic symptoms benefit from DBS in the Gpi
- Improvement of feeding dystonia had an important impact on quality of life