The methylmalonic acidemias (MMAs) are a group of inborn errors of metabolism resulting in the accumulation of methylmalonic acid in body tissues and fluids. A recognized complication of MMA is bilateral liquefaction of the globus pallidi, resulting in a fulminant total body dystonia of childhood often refractory to medical treatment. This case of total body dystonia due to MMA in a 4-year-old boy had been medically refractory for 15 months. Complete metabolic destructive liquefaction of the pallidi, that is, autopallidotomy, necessitated an alternative, bilateral subthalamic nucleus (STN) target for deep brain stimulation (DBS) with a marked improvement in dystonia and reduction in pain. The case illustrates the efficacy of STN DBS in this condition and the technical challenges in targeting the STN in a small child.
Santo Chakraborti, Harutomo Hasegawa, Daniel E. Lumsden, Wisam Ali, Margaret Kaminska, Jean-Pierre Lin and Keyoumars Ashkan
Charlotte Sayer, Daniel E. Lumsden, Sarah Perides, Kylee Tustin, Sanj Bassi, Jean-Pierre Lin and Margaret Kaminska
Intrathecal baclofen (ITB) is an effective management option for childhood hypertonia. Given the potential complications of implanted ITB pumps, trials of ITB are usually performed as part of the workup for ITB pumps. Two methods are used for ITB trials, lumbar puncture (LP) and catheter insertion into the intrathecal space. Little has been written to date on the number of positive trials and complications in trials. This study aimed to report the outcomes and complications in ITB trials for childhood hypertonia (dystonia, spastic, or mixed).
A retrospective case notes review was conducted of all patients who underwent ITB trials at the Evelina London Children’s Hospital between 2005 and 2012 (inclusive). Positive trials were defined as a reduction in Modified Ashworth Scale by a minimum of 1 point in at least 2 muscle groups and improvement reported by the caregivers in the areas of goals agreed upon between professionals and the families.
Our patient group comprised children with dystonia (n = 7), mixed spasticity/dystonia (n = 29), spasticity (n = 4), and pain (n = 1). A total of 47 trials were attempted in 41 children. Forty trials were successfully completed, with 39 being positive. Thirty-three were catheter trials, and 14 were LPs. The overall complication rate in the 47 attempted trials was 53%: 61% in catheter trials, and 36% in LP trials. This difference was not statistically significant. The most common complications were vomiting (n = 9) and CSF leak (n = 4). The most serious complication was meningitis (n = 1) in a catheter trial. No patients experienced a permanent injury.
There is a high risk of minor self-limiting complications with ITB trials, which needs to be factored into the decision process of progression to trials. The rate of positive trials in this study was 98%, of which 21% did not progress to pump implantation. While the authors would still advocate for ITB trials prior to ITB pump insertion to aid parental decision-making, this figure suggests that with good patient selection, ITB pumps could be placed without a preceding trial.