Upper Extremity Deep Vein Thrombosis After Botulinum Toxin Injection: A Case Report.

Botulinum toxin (BoNT) injection is widely used to improve spasticity. However, after the treatment, the patient may experience pain, inflammation, swelling and redness at the injection site. In this case, we addressed deep vein thrombosis (DVT) after BoNT treatment of the upper limb. A male aged 37 years had spasticity and dystonia in his left upper extremity. BoNT-A 100 U was injected into the left biceps brachii and an equal amount into the brachialis to relieve spasticity. After three days, he developed redness and painful swelling in the left upper arm and the next day, through the upper extremity computed tomography venography, DVT was identified in the left cephalic vein. The thrombus resolved after the anticoagulation therapy with rivaroxaban (Xarelto). We hypothesized the role of mainly three mechanisms in the development of DVT in this case: repetitive strenuous activity, relative stasis due to reduced muscle tone, and possible direct mechanical damage to the vessel wall.