To evaluate the therapeutic effect of low-dose haloperidol in patients with secondary dystonia. METHODS: Five patients were given oral haloperidol 0.5-4.5m/d, and the other one was given oral Antan 1mg Bid, Medopa 40mg Bid, and Valium 2.5mg Q8h. RESULTS: After the above treatment five patients showed significant improvement in symptoms and signs 1-5d after taking the drug, and the other patient did not show any improvement. Conclusion: Low-dose haloperidol (0.5-4.5mg/d) is safe and effective in the treatment of secondary dystonia. Fundamental project: “Eleventh Five-Year Plan” Science and Technology Support Project: Research on Key Technologies for the Treatment of Acute Occupational Poisoning (BAI06B01) Carbon monoxide poisoning COP or delayed COP encephalopathy However, the clinical manifestations and treatment of secondary dystonia have not been reported in detail with satisfactory results. The clinical manifestations and treatment of 6 patients admitted to our department from 2006 to 2009 are reported as follows: Subjects and methods 1. General data: 3 males and 3 females, age 24-65 years, duration of disease 2-8 months. 4 patients were transferred from outside hospitals. All had a clear history of severe COP coma. All of them had a clear history of severe COP coma and were awake for 1 to 2 d after treatment, and recovered rapidly to a stage similar to that before the disease, i.e. pseudo-healing. After 20-30 d of acute COP, the patients developed dementia, difficulty in movement, and increased muscle tone. The disease rapidly worsens, and the patient becomes unable to take care of himself or herself and becomes incontinent. In the following 3 weeks to 3 months, repetitive non-random movements and dystonia characterized by abnormal twisting postures appear. Four cases were characterized by abnormal twisting of the extremities, including non-random upward and inward movements of the upper extremities, elbow flexion and extension, hand fist clenching, forearm rotation, and distal movements of the lower extremities, such as knee extension and flexion, ankle and foot inversion and twisting, etc. In one case, in addition to abnormal movements of the extremities, there were also movements such as shoulder shrugging, neck turning, smacking, pouting, tongue extension, eyebrow squeezing, and eye blinking. The other case was accompanied by abnormal twisting of the trunk. The other case was accompanied by abnormal twisting of the trunk. The above abnormal myotonic movements lasted 10-30 min each time with a frequency of 10-30 times/min. In severe cases, they were almost continuous. Most of the episodes occurred during waking hours and disappeared during sleep. EEG: In three cases, the background EEG waves were mainly 1.5-3Hz δ waves or 4Hz theta waves, with little or no alpha activity. 1 case had 8.5Hz α rhythm, waveform rhythm was poor. No spike wave was seen in any of them, and flash stimulation did not induce epileptic seizures. The position-related potentials (P300) were examined in three patients, and in one case, the peak latencies of all segments were normal, and the peak latencies of all points of the target stimulation potentials were normal, and the waveform differentiation was acceptable. This suggests normal cognitive function. In the other two cases, the wave crest latencies were normal in all segments, and the wave crest latencies at all points of the target stimulation potential were normal or prolonged, and the waveform differentiation was poor. This suggests poor cognitive function. 4. 4. treatment: along with hyperbaric oxygen and symptomatic support, oral haloperidol was given at a starting dose of 0.5 mg/d, with a maintenance dose of 0.5 mg/d in 3 patients. in the other 2 cases, the starting dose was 0.5 mg/d, and the dose was gradually increased by 0.5 mg/d each time, with a maintenance dose of 1-4.5 mg/d. In 1 patient, 3 drugs were combined: oral methyldopa 40 mg each time, twice daily. One patient was given a combination of three drugs: oral methadone 40 mg twice daily, and Antanil 1 mg twice daily, and Valium 2.5 mg once every 8 h. The effect of 0.5mg/d was satisfactory in 3 patients, and the non-random movement disappeared in 2-4 d. In 1 case, the starting dose was 0.5mg/d, and the dose was increased by 0.5mg/d to 1mg/d after 3 d. After the dose was increased, the patient’s muscle tone of both upper limbs decreased significantly, and he did not wake up after sleeping, but improved after the dose was reduced, and the effect of maintaining 0.5mg/d was good. In the other 2 cases, the effect was unsatisfactory at the starting dose, and the dose was gradually increased to 0.5mg/d each time to achieve a satisfactory effect of 1mg and 4.5mg/d, with complete disappearance of non-random movements. 5 patients were not seen to have another seizure at the follow-up until publication. In patients with three consecutive drugs, the number of non-random movements decreased initially, and after 3-4 d, difficulty in walking, mask face and reduced muscle tone of both upper limbs appeared. The patient was discontinued from Antan, and the dose of Andin was reduced to 2.5 mg/d without improvement, and then discharged spontaneously and stopped the medication. Discussion Dystonia is a group of syndromes in which the contraction of synergistic and antagonistic muscles of the body’s skeletal muscles is uncoordinated, causing intermittent or excessive persistent contractions resulting in repeated involuntary movements and abnormal torsional postures with a variety of clinical manifestations. Secondary dystonia accounts for about 20%-30% of cases, and is commonly caused by cerebral palsy, brain tumors, traumatic brain injury or antipsychotic drugs, and has also been reported as a result of exposure to toxic substances . Dystonia due to COP is rarely reported. All six patients were admitted to the hospital with “DNS” after “COP”, none of them had previous episodes of this disorder, no family history of similar disorders, and no history of long-term heavy use of antipsychotic drugs, so it does not support “primary dystonia “There was no family history of similar episodes and no history of long-term heavy antipsychotic medication. Four patients developed dystonia in different ways between 3 weeks and 3.5 months after the onset of DNS. The age of the patients ranged from 24 to 65 years, so age was not a determining factor in the onset of the disease. The patients presented mainly with abnormal movements of the extremities, in addition to one case with somatic dyskinesia and another with abnormal movements of the head and neck. The basal ganglia lesion was seen on imaging in 5 patients, which is consistent with the imaging of secondary extrapyramidal lesions, but no thalamic lesion was seen in any of the patients, which is not entirely consistent with the report in the domestic and international literature that the most vulnerable sites in patients with dystonia are the basal ganglia and the thalamus, and extensive symmetrical diffuse lesions in the white matter of the brain were seen in each patient, which is consistent with the report in the literature of demyelinating lesions in the white matter of the brain after COP and is consistent with late-onset encephalopathy brain changes. Extrapyramidal symptoms such as hypertonia and tremor are common in ACOP and DNS, and more than 95% of the patients showed significant improvement or disappearance of extrapyramidal symptoms with improvement, and no special medication is usually required. There are reports in the literature that treatment of secondary dystonia can be done with haloperidol or Antan, Valium if necessary, and botulinum toxin if the drug is not well controlled. Surgical treatment has also been reported. In these 6 patients with secondary dystonia, pharmacological treatment should be the first choice for symptom control. From the analysis of the treatment results of three patients, the application of low-dose haloperidol 0.5 mg/d could significantly improve the symptoms. It was maintained at this dose. During the course of medication, patients with very small dose increases may become drowsy and should stop the medication at that time. When symptoms reappear, caution should be exercised if the dose is increased, and the treatment dose needs to be individualized. 5 patients were able to control their symptoms with only one drug. Another patient did not improve with the combination of 3 drugs. Consider the combination of several drugs to increase adverse effects as another form of extrapyramidal manifestations. Haloperidol is an antipsychotic drug, and its mechanism of improving dystonia is unclear. As seen in this report, the treatment of secondary dystonia should follow the principle of small doses and needs to be individualized. Evidence from its inquisitorial medicine is still needed for a large sample of randomized controlled studies.