Local injection of botulinum toxin type A in the treatment of thalamic ataxia syndrome: A case report.

[RATIONALE] Thalamic ataxia syndrome is a rare but severely disabling condition resulting from thalamic lesions, characterized by persistent motor incoordination that frequently fails to respond to conventional rehabilitation therapies. Given the lack of effective treatment options and the profound impact on patients' quality of life, this study aimed to evaluate the efficacy of local botulinum toxin type A (BoNT-A) injections as a potential breakthrough treatment for improving motor control and daily living activities in patients with thalamic ataxia. This investigation represents the first clinical application of BoNT-A specifically targeting thalamic ataxia, offering new hope for treatment-resistant cases.

[PATIENT CONCERNS] A 59-year-old female presented with a 6-month history of debilitating left limb movement disorder, including inability to lift the left upper limb, grasp objects, or perform essential daily activities such as eating and carrying a cup. Despite 5 months of intensive rehabilitation, her symptoms showed minimal improvement, leaving her functionally dependent.

[DIAGNOSIS] The patient was diagnosed with thalamic ataxia syndrome secondary to right thalamic hemorrhage, confirmed by cranial CT and MRI.

[INTERVENTIONS] The patient received precisely targeted local BoNT-A injections (total 130U) into the affected upper limb muscles (deltoid, biceps brachii, flexor carpi radialis, flexor carpi ulnaris, pronator teres, extensor carpi radialis, and flexor digitorum superficialis) under dual ultrasound and electromyography guidance, ensuring optimal muscle selection and dosing accuracy.

[OUTCOMES] Three weeks postinjection, the International Cooperative Ataxia Rating Scale score decreased by 8 points (from 24 to 16), with the most significant improvement in dynamic function (upper limb ataxia subscores reduced from 18 to 10). The Fugl-Meyer Assessment Upper Extremity Scale increased by 6 points (from 52 to 58), particularly in hand coordination and speed tasks. The modified Barthel index improved by 9 points (from 85 to 94), enabling independent performance of previously difficult activities like self-feeding and cup handling.

[LESSONS] Local BoNT-A injections represent a novel and potentially transformative treatment for thalamic ataxia syndrome, particularly in cases refractory to conventional therapies. These findings challenge current rehabilitation paradigms and highlight the need for further studies with larger cohorts to validate and expand upon these findings.