Acute urinary retention in two patients after subthalamic nucleus deep brain stimulation (STN‐DBS) for the treatment of advanced Parkinson's disease

Chorea-acanthocytosis (ChAc) is a hereditary neurodegenerative disease characterized by hyperkinesias, peripheral neuropathy, and erythrocyte acanthocytosis. ChAc belongs to the group of neuroacanthocytosis syndromes, including ChAc, McLeod syndrome, Huntington’s disease-like 2 and pantothenate kinase associated neurodegeneration. ChAc diagnosis can be confirmed by the absence of chorein in western blot of erythrocyte membranes. Medical treatment (botulinum toxin A injections, tetrabenazine and atypical neuroleptics) is only partially effective. Functional surgery has been tried in ChAc with variable results. We report a case of ChAc treated with bilateral deep brain stimulation (DBS) of the internal globus pallidum (GPi) with positive results. The patient is a 35-year-old woman without family history of movement disorders. At 25, she began to note tongue and lip biting, movement disorders and mild loss of postural reflexes. On examination she had dysarthria, oromandibular dystonia, mild chorea, and irregular choreic gait with occasional flexor truncal spasms. Further neurological examination was unremarkable except for hyporeflexia. She was cognitively intact, save for moderate impairment to solve problems as showed in the Tower of Hanoi test. Performance in orientation, attention, language, visuospatial abilities and executive functions was within normal limits. Laboratory tests revealed acanthocytosis (up to 20%) and increased creatine kinase. Electromyography showed axonal neuropathy in the lower limbs. CT and MRI scans showed mild dilatation of lateral ventricles and slight atrophy of the head of the caudate nucleus. Genetic testing for Huntington’s disease was negative. The clinical diagnosis was confirmed by the absence of chorein in western blot of erythrocyte membranes. The patient was treated first with olanzapine, then with tetrabenazine, amantadine and clozapine with transient benefit. With the passage of time, her chorea gradually worsened and the trunk spasm increased in frequency and severity. After discussing different options with the patient, she opted for DBS. After written consent was obtained, she underwent bilateral implantation of a quadripolar electrode (DBS 3387, Medtronic) into the GPi under generalized anaesthesia. Image study included CT/MRI fusion imaging coupled with a stereotaxic atlas map. Targeting and electrode implantation were performed according to previously described methods. Initial coordinates were 3 mm in front of midcomisural point; 21 mm lateral from midline, and 4 mm ventral to AC-PC line. For physiological verification we used microelectrode recording, visual evoked potentials and macrostimulation. Postoperatively, the benefit was rapidly evident with marked improvement in both dystonia and chorea. Chorea responded faster than dystonia. The patient was able to walk independently and her truncal spasms almost disappeared, but dysarthria did not improve. Two months postoperatively the improvement was confirmed (video). Chorea-dystonia items (motor section) of Unified Huntington’s Disease Rating Scale (UHDRS) scored 24 in the preoperative evaluation, and 14 in the 2 month postoperative evaluation. Over the subsequent 2 years, she needed a progressive increase in electrical parameters to maintain her improvement since the trunk spasms reappeared although not with the same severity; in addition, she developed occasional freezing of gait. At present electric parameters are as follows: