A case report of serious brain and lung injury caused by mistakenly taking Mosquito repellent liquid contains Meperfluthrin


 Background

Mosquito repellent liquid containing Meperfluthrin is widely used in the daily life. Among all clinical cases that children take mosquito repellent by mistake, only a fewwere recorded with serious brain and lung damages caused by Meperfluthrin.
Case presentation:

This case report presents a 16-month-old child in Xiamen City of China with severe brain and lung injury caused by mistakenly taking mosquito repellent that contains 0.8% Meperfluthrin. The child was treated with mechanical ventilation, fiberoptic bronchoalveolar lavage, anti-infection, 20% mannitol for dehydration, ganglioside and neurologic rehabilitation. The child recovered after 2 months.
Conclusion

This case shows that the improper administration of Meperfluthrin may cause serious toxic damage to brain and lung. Clinicians and parents should pay attention to prevention and targeting treatment promptly after intoxication.


Conclusion
This case shows that the improper administration of Meper uthrin may cause serious toxic damage to brain and lung. Clinicians and parents should pay attention to prevention and targeting treatment promptly after intoxication.

Background
Meper uthrin is a pyrethroid insecticide invented and used in China. It is widely used in mosquitorepellent incense and its derivative products because of its high e ciency, low toxicity and convenient use. Among all clinical cases that children taking mosquito repellent by mistakes, only a few were recorded serious poisoning symptoms caused by Meper uthrin. We have only retrieved one serious poisoning case caused by mistakenly taking mosquito repellent liquid containing Meper uthrin reported by Li Jiru, a doctor from Shengjing Hospital a liated to Shenyang Medical University of China in July 2019 [2], and now we report a case of persistent convulsion, progressive lung damage and brain damage caused by the accidental administration ofmosquito repellent liquid containsMeper uthrin.

Case Presentation
On June 28, 2019, a 16-month-year old male with coma and convulsion was admitted to the ER of Xiamen Children's Hospital. No history of food poisoning was reported at that time, and there was no medical history before the admission. The physical examination showed: T 35.6 ℃, P 161 times/min, BP 75/35 mmHg (1 mmHg = 0.133 kPa), R 58 times/min, oxygen saturation was 56% without oxygen inhalation. Patient was unconscious with short of breath, convulsed, and both eyes quaked horizontally.
Patient has cyanosis, with 3 mm diameter in pupils, showed slow light re ex, neck resistance was normal, apping of nasal alae, positive triple-concave sign, coarse respiratory sounds in both lungs, and a few wet rales, CRT > 2 s. Chloral hydrate, phenobarbital, midazolam and propofol were given in order for sedation, the convulsion lasted for about 35 minutes and relieved after treatment, dyspnea was observed after sedation. Patient was treated with mechanical ventilation, and propofol was then used to help the patient to maintain sedated for chest radiography ( Figure 1A: shows a little exudation of the lungs) and craniocerebral CT (Figure 2: no obvious abnormalities on craniocerebral CT). Patient was then transferred to PICU. Fibrobronchoscopy was conducted on the day of admission. Result showed hyperemia and edema on mucous membrane without erosion and foreign body (Fig. 3A, B). Results of blood test were as The patient developed a fever of 38.5 ℃ on the second day of admission, with increased lung rales, short of breath and dyspnea. Multiple patchy shadows in both lungs were seen on the bedside chest radiograph (Fig. 1B), which was more progressive than the day of admission. Methylprednisolone was prescribed by the patient's weight(1mg/kg) and used twice a day to resist in ammation; budesonide for atomization, and injection of Mucosolvan was applied for the purpose of resolving phlegm. Bedside chest radiograph was performed on the third (Fig.1C) and fth day (Fig.1D) after admission, respectively. Fig.1C showed the continued exudation in both lungs and atelectasis appeared; Fig.1D showed atelectasis in the right lower lobe and the left upper lobe, and multiple strips of dense shadows in both lungs. On the 6th day after admission, more secretions were showed in broncho broscopy (Fig. 3C), and alveolar lavage was used. The temperature dropped to normal on the 7th day after admission.
The patient was withdrawn from the ventilator on the 15th day after admission. Oxygen saturation was back to normal under nasal catheter oxygen inhalation. Blood test result and CRP were normal. After discontinuation of sedative treatment, patient regained consciousness but with sluggish reaction. Patient was unable to speak and laugh, and there is paroxysmal limb involuntary shaking, slightly increased muscle tension. EEG showed the diffused 2.0-4.0 hz slow wave activity (Fig.5). Cranial MRI showed abnormal signal beside the anterior horn of the right lateral ventricle (Fig.6), therefore softening focus was considered. Meper uthrin poisoning was considered by the information that "an empty insect repellent bottle was found beside the patient in the incident scene" provided by patients' parents at that time. Therefore, ganglioside nutrition brain cells and hyperbaric oxygen treatment were prescribed. The bedside X-ray chest lm (Fig. 1E) showed signi cant absorption of lung exudation on the 20 days after admission, and patient exhibited an improved reaction, with limb tremor eased, patient was then transferred to the rehabilitation center. The patient was fully recovered in the follow-up session after two months of discharged.

Discussion And Conclusions
Pyrethroid pesticides are one of the most widely used agricultural and household pesticides, accounting for nearly 25% of the global pesticide market [3]. Poisoning incidents caused by pyrethroid pesticides are frequently reported. According to the latest statistic of the Toxicant Exposure Monitoring System of the American Association of Poison Control Centers, pesticide poisoning ranks the ninth among all types of poisoning, which accounts for 3.28% of all intoxication incidents. In China, chenshuyang et Al. [5] analyzed and found 2954 reported cases of pesticide poisoning from 1992 to 2003, accounting for 3.21% of all poisoning cases. Meper uthrin is also a kind of pyrethroid insecticide, which is often used for mosquito incense, mosquito incense tablets and liquid mosquito incense products, with a concentration of 0.8%, few with concentration of 0.6%, and widely used in Chinese families.
Pyrethroid pesticides are classi ed into two types based on different chemical structure. Type I does not contain the cyano group (such as pyrethrin) but type II does (such as cypermethrin, deltamethrin) [6] , which is alipid-soluble chemical compound that can pass through the blood-brain barrier effectively. It mainly targets and changes the sensitivity of the voltage-gated sodium channels, which keeps the sodium channels open, so the sodium ions ow into the cell and prolong the depolarization,and causes abnormal excitation of the nerve cells. It has been shown that sodium channels in the dorsal root ganglion and peripheral nerves of mammals are more sensitive to type II pyrethroids than type I before sexually mature, and type II can also keep the sodium channel open longer than type I. It has also been suggested that type II pyrethroids can control the voltage-dependent chloride channels in the brain, nerves, muscles and salivary glands, thereby reducing the chloride channel currents [7] . At higher concentrations, pyrethroids can act on the GABA-gated chloride channels, leading to severe type II toxic convulsions. Romero et al [8] found that pyrethroid metabolism produces superoxide anion, hydroxyl radicals and hydrogen peroxide free radicals. Kanbur et al [9] found that cypermethrin exposure increases oxidative stress (malondialdehyde, nitric oxide) in the rat brain, while superoxide dismutase(SOD), antioxidant enzymes such as catalase(CAT) and glutathione peroxidase(GSH-Px) decreased signi cantly, and this phenomenon became more obvious with prolongation of exposure time.
Because sodium channels are located in type I and type II alveolar epithelium, the permeation gradient may be destroyed by pyrethroids, leading to airway and bronchial mucosal edema [10] . Due to the hypersensitivity caused by pyrethroids, the ongoing in ammatory reaction may also be one of the factors that cause lung damage. In addition, the damages caused by certain organic solvents in pyrethroid drugs, such as chloroform, benzene and ether, may also be the cause of lung lesions.
Pyrethroid drugs are often taken by mistake, mild poisoning can be manifested as upper respiratory tract irritation, cough, sore throat, dizziness, headache, nausea, vomiting, abdominal pain, fatigue, chest tightness, sensory abnormalities. Serious poisoning may cause disturbance of consciousness, seizures, severe pneumonia, dyspnea, cyanosis and coma [6] , death is more unlikely to occur [11] . Neurological symptoms are one of the main clinical manifestations [12] , type II poisoning can cause muscle clonus and paroxysmal tonic convulsion, similar to epilepsy [13] . The concentration of the drug in this case is 0.8%, and it caused severe convulsion, shortness of breath, dyspnea and progressive lung injury and brain damage. The patient recovered fully after treatment.
When patient is diagnosed with pyrethroid poisoning, 2% -4% sodium bicarbonate should be used for gastric lavage, and then medicinal carbon should be applied for absorbing the residual solution in the stomach. Because the toxin can cause serious lung injury and nervous system damage, active measures such as controlling static shock, reducing cranial pressure, respiratory support; mechanical ventilation, corticosteroids injection, anti-oxidative stress, infection prevention should be considered in sever case.
Atropine in small dosage can also be applied, but atropinization is not recommended. Although pyrethroids belong to the low toxic drugs, they are more likely to cause continuous convulsion, progressive lung injury and even ARDS. Therefore, blood puri cation should be carried out as early as possible.
Because pyrethroid insecticides are widely used, medical staff needs to pay more attention on health education, reminding parents to prevent children from taking them by mistake. Meanwhile, manufacturers also need tobe alter and have the emergency directions for mistakenly intake, so as to improve the awareness of poisoning and minimize such accidental injuries.

Declarations
Ethics approval and consent to participate The case report has been approved by the Ethics Management Committee of Xiamen Children's Hospital Consent for publication Not applicable Availability of data and materials Not applicable