The Extreme Ends of the Treatment Response Spectrum to Botulinum Toxin in Cervical Dystonia

Abstract

Background: The response to BoNT is not uniform; a broad spectrum of responses and side-effects usually occurs. This study aimed to show special cervical dystonia cases with therapy response very different to normal treatment course which indicate the extreme ends of therapy spectrum. Patients: Clinical data and course of treatment of five long-term treated patients with cervical dystonia out of therapy response norms are presented: a patient who was supersensitive to standard dose and has required dose adjustment to lower dose of BoNT; one patient who worsened under a standard dose, but responded excellently to twice the standard dose; one insensitive patient who responded poorly for years to a dose well above the standard dose, but responded when dose was further increased; and two patients with a totally different response pattern to BoNT/A preparation 1, but the development of a neutralizing antibody induced secondary treatment failure in both cases and a totally different response after switch to BoNT/A preparation 2. Conclusions: These five patients indicate that the response of a patient to a BoNT preparation may be unexpected. Therefore, cautious onset of BoNT therapy is recommended as well as consequent dose adjustment later on and even switch to another BoNT/A preparation when a patient has already developed NABs against BoNT/A.

Lessons about Botulinum Toxin A Therapy from Cervical Dystonia Patients Drawing the Course of Disease: A Pilot Study

“…This implies that most patients are reinjected well before the clinical effect of the previous injection has fully declined, and that patients experience a “staircase-like” improvement, injection by injection. This phenomenon is presented in detail in [ 23 ]. The outcomes of the present study do not include the analysis of the development of the peak effect at approximately four weeks after injection, but rather a continuous, stable plateau of improvement which is achieved via repeated injections at a fixed interval of 3 months and an analysis of the severity of CD at the end of an injection cycle.…”

“…In a review from 2003, a benefit from BoNT therapy was reported in 70–85% of CD patients [ 25 ]. The long-term outcome from BoNT therapy depends on a variety of factors: the genetic constellation of the patient (see next paragraph), the BoNT preparation used [ 23 , 26 ], the dose per session, the length of the treatment cycle, the clinician’s knowledge about optimal injection sites for muscles (detailed in [ 27 , 28 ]), and the duration of the treatment [ 26 ].…”

No Secondary Treatment Failure during Incobotulinumtoxin—A Long-Term Treatment Demonstrated by the Drawing of Disease Severity

“…This further emphasizes the necessity for the adaptation of the dose to clinical needs. In a previous paper, we emphasized that in patients with fairly high initial severity (as in the DR subgroup of the present cohort), an unusually high dose may be necessary at the beginning of BoNT therapy to achieve a satisfying response [ 31 ]. If this adaptation is not performed, the risk is high that the patient terminates BoNT therapy and is classified as a primary non-responder [ 31 ].…”

The Impact of the Course of Disease before Botulinum Toxin Therapy on the Course of Treatment and Long-Term Outcome in Cervical Dystonia

“…The reasons for discontinuation are poorly understood [ 21 ]. As in children with cerebral palsy (CP) [ 22 ] primary non-response [ 17 , 23 ], disease progression [ 24 , 25 , 26 , 27 ], cost of therapy, inconvenience, side effects and incorrect diagnoses [ 21 , 22 , 28 ] contribute to discontinuation of BoNT therapy in CD. Special types of CD as antecollis are associated with moderate to severe side-effects and high withdrawl rates [ 24 , 29 , 30 ].…”