The patient, a 25-year-old female, was admitted to the hospital due to progressive slurred speech and dysphagia for 18 days on August 20, 2024. On July 28, 2024, the patient received face and shoulder injection of botulinum toxin labeled as “South Korea imported” (total amount of 200U, divided into 2 bottles) in non-medical institutions in Mujie City, Myanmar. On the fourth day after injection (August 1), dizziness developed, and dysarthria, dysphagia, and neck muscle weakness developed the next morning. He was transferred to Ruili Jingcheng Hospital for nutritional support on August 11. On August 19, he was placed with a gastric tube due to dysphagia. There was no fever, disturbance of consciousness or abnormal physical activity during the course of the disease. Physical examination: vital signs: heart rate 119 beats/min (sinus), the rest of the normal. Nervous system: clear consciousness, dysarthsia (NIHSS score 1), decreased bilateral pharyngeal reflex, cervical flexion muscle strength grade IV, limb muscle strength grade V-, normal and symmetrical muscle tension, normal depth and superficial sensation, and negative pathological signs. Meningeal irritation was negative. Auxiliary examination: one. Neurogenic electromyography changes, peripheral nerve motor fiber axon moderate to severe damage, mainly in the upper limbs; two. Severe neuromuscular junction damage. Treatment and outcome: intravenous infusion of botulinum antitoxin 50 000 U, methylprednisolone pulse therapy (500 mg/d×3d), nasal feeding nutritional support and rehabilitation training. On the third day of treatment, swallowing function improved, and the gastric tube was removed on the seventh day. He was discharged after 21 days of hospitalization with complete symptom resolution (Fig. 1).

Notes: (1) Electrophysiological diagnosis of NCS+ sensory disorders of extremities +F wave: decreased amplitude of motor conduction fibers in bilateral median nerves, bilateral ulnar nerves and bilateral common peroneal nerves, decreased occurrence rate of F wave (decreased M wave) in bilateral median nerves, and no obvious abnormalities were found in other nerves. (2) Repetitive electrical stimulation: (1) Low frequency stimulation: the ulnar nerve amplitude decreased by 10.8%, and the accessory nerve amplitude decreased by 16.7%; (2) High frequency stimulation: the amplitude of ulnar nerve increased. 3. EMG: a small amount of spontaneous potentials were observed in the examined muscles. The waveforms of the muscles with light contraction were poorly differentiated, and no obvious abnormalities were observed in the muscles with strong recruitment

A 50-year-old female patient was admitted to the hospital due to progressive dysarthria with dysphagia for 3 days on August 19, 2024. On August 12, 2024, the patient received bilateral masseter injection labeled “South Korea imported botulinum toxin” (100U), and bilateral periocular injection in non-medical institutions. On the 4th day after operation, he developed slurred speech, choking and weakness of limbs, and the symptoms continued to progress during the treatment in Baoshan People’s Hospital. Physical examination: Vital signs: heart rate 112 beats/min (sinus), rest normal. Nervous system: conscious, dysarthsia (NIHSS score 2), bilateral soft palate weakness, pharyngeal reflex loss, bilateral orbicularis oculi muscle strength grade IV, masseter muscle strength grade III, proximal limb muscle strength grade IV, distal limb muscle strength grade V-, deep and shallow sensory symmetry, bilateral Hoffmann sign negative.

Auxiliary examination: Neurogenic electromyography changes, peripheral nerve motor fiber axonal mild to moderate damage, mainly in the upper limbs; Moderate neuromuscular junction damage. Treatment and outcome: After the diagnosis was established, botulinum antitoxin 100 000 IU intravenous infusion, methylprednisolone 500 mg/d pulse therapy, swallowing rehabilitation training and nutritional support were started. After 17 days of hospitalization, the symptoms were significantly relieved and the patient was discharged (Fig. 2).

Notes: (1) Electrophysiological diagnosis of NCS+ sensory disorders of extremities +F wave: decreased amplitude of motor conduction fibers in bilateral median nerve and bilateral ulnar nerve, decreased F-wave elicited rate in left median nerve, and no obvious abnormalities were found in other nerves. 2. Repetitive electrical stimulation: (1) Low frequency stimulation: the ulnar nerve amplitude decreased by 8%, and the accessory nerve amplitude decreased by 26.4%; (2) High frequency stimulation: the amplitude of ulnar nerve increased. 3. EMG: there were no obvious abnormalities in spontaneous potential, light contraction and vigorous recruitment of muscles

A 49-year-old female patient was admitted to the hospital due to “progressive ptosis with dysphagia for 7 days” on August 7, 2024. On behalf of the patient’s family, the patient received bilateral masseter muscle injection of “botulinum toxin six-peptide lyophilized powder” (unknown dose) at a non-medical institution on August 2, and pain at the injection site occurred on the day after surgery. On August 5, a sudden onset of ptosis, dysphagia, and generalized myalgia occurred. The patient was transferred to our hospital after ineffective treatment in other hospitals. Physical examination: Vital signs: body temperature 37.8℃, heart rate 108 beats/min. Nervous system: bilateral ptosis (right eye fissure 3 mm/ left eye fissure 4 mm), pupil hypersensitivity to light reflex, normal bilateral eye movements in all directions, dysarthria (NIHSS score 3). Muscle strength of the extremities was grade III proximal and grade IV distal. Auxiliary examination: Nerve conduction study: Neurogenic electromyography changes, peripheral nerve motor fiber axonal moderate to severe damage; Severe neuromuscular junction damage. Treatment and outcome: botulinum antitoxin 100 000 IU intravenous infusion, methylprednisolone 500 mg/d pulse therapy, rehabilitation training and nutritional support. After 29 days of hospitalization, the symptoms were significantly relieved and the patient was discharged (Fig. 3).

Notes: 1.Electrophysiological diagnosis of NCS+ sensory disorders of extremities +F wave: decreased amplitude of motor conduction fibers in bilateral median nerves, bilateral ulnar nerves and left common peroneal nerves, decreased F-wave elicited rate in bilateral median nerves, bilateral ulnar nerves and bilateral tibial nerves, and no obvious abnormalities were found in other nerves. 2. Repetitive electrical stimulation: (1) Low-frequency stimulation: the amplitude of ulnar nerve decreased by 6.5%, and the amplitude of accessory nerve decreased by 21.2%; (2) High frequency stimulation: the amplitude of ulnar nerve increased. 3. Electromyography (EMG): the spontaneous potential, light contraction and vigorous recruitment of the examined muscles were normal