Asia Pacific Journal of Medical Toxicology
Volume:3 Issue: 3, Summer 2014

In recent decades, the science of toxicology in Asia Pacific (AP) region has been expanding. In this study, the productivity of the science of toxicology in the timeframe of the years 1996 to 2013 in AP region was evaluated and was compared with Northern America (NA) region. The SCImago portal was accessed to obtain the scientific indicators of toxicology science. The subject category of «toxicology» was used. In the SCImago portal, the AP region is divided into three sub-regions, Asiatic (AS), Pacific (PA) and Middle East (ME). To standardize the results, number of documents and citations of AP sub-regions in each time point were divided by their corresponding information from NA region. In 1996, 3674 toxicology documents were published from NA region while in the same time 1308 documents were published from AS, 130 from PA and 144 from ME. These figures increased to 3985, 3893, 354 and 788 in the year 2013. While the total number of publications per year remained relatively stable in NA region over this 18-year period, this figure increased for AS and PA regions by about 3 times and for ME by about 5 times. The number of citations in the field of toxicology in AS, ME and PA regions, however, is still far behind NA. The percentage of toxicology documents that were produced through international collaboration in PA region was considerably higher than NA, AS and ME regions. The productivity of toxicology science in AP region has been increased over the past 18 years, though the level of citations is low compared to NA countries. International collaborations should be seriously considered and strengthen in AP countries.

For effective treatment of organophosphate (OP) poisoning, development of a standardized protocol with flexible dose regimen for atropine and pralidoxime is an essential step. In this study, we aimed to assess the protocol devised in our setting; Bach Mai Hospital Poison Treatment Center, for treatment of OP poisoning that included a higher dose regimen of pralidoxime (2PAM). A protocol for treatment of OP poisoning was developed during 1995 to 1996, which included an atropinization scoring scale and a modification of 2PAM dose regimen. In this study, OP poisoned patients who were treated during 1997 to 2002 with the new protocol (study group or cases) were compared with historical control group which included OP poisoned patients treated between 1993 and 1994 prior to establishment of the new protocol. One-hundred and eight cases and 54 controls were included. The cases and controls were not significantly different according to age, gender and plasma cholinesterase activity on admission from each other. There was no significant difference of mean duration of 2PAM therapy between the two groups. The controls received mean total 2PAM dose of 7.2±4.1 g, while the patients in the study group received 20.0±12.7 g which was 2.77 times higher than the dose for control group (P<0.001). Patients in the study group received significantly lower doses of atropine (100.2±119.1 vs. 231.8±225.5, P<0.001). Patients in the study group required a shorter duration of hospital stay compared to controls (6.2±4.8 vs. 8.2±5.8, P=0.035). In addition, morality rate decreased significantly (P=0.004) from 13% to 1.9% by application of the new protocol. The new protocol was more effective for patients with OP toxicity as it reduced the morbidities and mortality. A flexible regimen of 2PAM therapy for OP poisoning is recommended to be implemented.

In Iran, methadone has been used for methadone maintenance treatment (MMT) as well as analgesic treatment in pain clinics. Recently, there are some reports regarding accidental and intentional methadone poisonings and deaths. The aim of this study was to evaluate the trend of methadone poisonings and deaths during a 10-year period in Tehran, Iran. This was a retrospective cross-sectional study over 2000 to 2010. Patients with a documented methadone poisoning who were admitted in Loghman Hakim Hospital Poison Center in Tehran, Iran were identified and included in the study. The data including patients’ age, gender, ingested dose, co-ingestants, intention of ingestion and outcome were extracted from the patients’ medical records. During the study period, 1426 cases of methadone poisoning were recorded, of which, 1041 cases (73%) were men. Thirty-six cases (2.5%) died. Mean age of the patients was 29.9 ± 17 years. In 476 cases, the intention of poisoning could not be determined, and in the remaining, the intention was misuse (n = 273, 28.7%), suicide (n = 254, 26.7%), accidental (n = 245, 25.8%) and abuse (n = 178, 18.8%). Mean of the ingested dose of methadone was 120.6 ± 306.8 mg. The incidence of acute methadone poisoning per one million population of Tehran was 0.43 in 2000 that rose to 37.62 in 2010. The results indicate that methadone poisoning and deaths have increased in Tehran. MMT clinics should be strictly run according to the national guideline to prevent methadone poisoning. With regard to high frequency of poly-drug use in methadone poisoning, it seems important to warn health care providers against prescription of other drugs with methadone.

Trinitrotoluene (TNT) is one of the most well-known and oldest explosive agents. In the recent decade, bioenvironmental, biochemical, and biological effects of TNT exposure have been more in the spotlight. In this study, we aimed to evaluate spirometric parameters in workers of a TNT factory exposed to TNT and other related fumes and dusts compared with the unexposed controls. In this case-control study, spirometry was done for TNT factory workers (cases) and matched healthy controls, and their results were compared with each other. Matched controls were selected from workers who worked in the same geographic area without any history of TNT or other chemical materials exposure. Spirometric studies were done during the early hours of day. Overall, 90 subjects (47 TNT exposed cases and 43 controls) were included. The two groups showed no significant difference in demographic characteristics and smoking habits. In spirometry, it was found that the cases had significantly lower forced vital capacity (91.4 ± 13.7% vs. 100.2 ± 13.0%, P = 0.002), forced expiratory volume in 1 second (98.0 ± 14.9% vs. 104.7 ± 12.5%, P = 0.024) and peak expiratory flow (98.4 ± 17.3% vs. 107.9 ± 21.7%, P = 0.025) compared with controls. According to spirometric findings, 10 cases (21.3%) and no controls had restrictive pattern, which means TNT factory workers had 1.27 (CI: 1.09-1.47, P = 0.001) fold risk for development of restrictive patterns. Chronic exposure to TNT or prolonged working in TNT factories may predispose the workers to respiratory disorders. In addition to regular screening programs, preventive measures and devices should be considered for TNT factory workers to reduce the harms.

Profile of acute poisonings varies from country to country depending on the ease of availability of substances and socio-economic condition of people; however, very little information from the United Arab Emirates (UAE) have been published, so far. This study was designed to find out the most common causes of overdose and poisoning in patients admitted to the emergency department of Rashid Hospital (RH), Dubai, UAE. In this retrospective cross sectional study, medical records of poisoned patients admitted to RH from 1st January 2012 to 31st December 2012 were reviewed. Demographic data, types of substances used, intention, length of hospital stay and outcomes were recorded in pre-designed checklists. Overall, 163 patients were studied that among them gender distribution was relatively equal (male: female = 1.04: 1). Mean age of patients was 30.3 ± 11.5 and most patients were in the age group of 20 to 29 years age old (41.7%). Rgarding the type of poisons, the majority of patients were poisoned with pharmaceuticals (55.8%) followed by chemical substances (23.3%). In pharmaceutical poisonings, most cases were due to multi-drug ingestion (22.6%), followed by ingestion of paracetamol (14.1%) and benzodiazepines (4.3%). Considering the gender distribution, women were significantly more involved with pharmaceutical poisoning (P = 0.046), while venomous envenomation occurred only in men indicating a significant difference (P = 0.004). In chemical poisoning, most cases were due to ingestion of corrosive agents (19%). Suicidal poisoning was significantly more common in women (P < 0.001), while abuse was significantly more common in men (P < 0.001). Length of hospital stay averaged on 8.1 days. Only 3 patients died during the admission (mortality rate: 1.8%). Study on, training for and prevention of poisoning should receive more attention in the UAE. Over-the-counter drugs especially paracetamol should be prescribed in a more controlled manner.

Organophosphate (OP) poisoning is one of the most common causes of poisoning in developing countries especially in Southeastern Asia. Poisoning with phosphorus-containing organic chemicals or OP compounds can be managed with antidotes like oximes which are potential reactivators of acetylcholinesterase (AChE). The efficacy of oxime therapy in OP poisoned patients mainly depends upon various factors such as different dose plans, infusion rate of oximes, genetic differences of patients, type of oxime used and chemical nature of the OP compound ingested. Studies on pralidoxime kinetics in OP poisoned patients have shown that reactivation of AChE depends on the plasma concentration of oximes as well as OP compounds. The plasma concentration of oximes mainly depends on the dose plan from intermittent injection to continuous infusion after a loading dose. The incontrovertible fact is that the intermittent dosing of oximes results in deep troughs in blood pralidoxime/oxime levels (BPL) whereas continuous infusion of oximes maintains steady state plasma concentrations. Many published literature also highlighted pralidoxime via continuous infusion results in better outcomes with minimum fluctuation in BPL compared to intermittent dosing. At therapeutic doses, adverse effects of oximes are reported to be minimal. But high BPL is associated with some common adverse effects including dizziness, blurred vision and diastolic hypertension. Considering all the facts, it is important to note that kinetic studies of oximes are useful not only in deciding the dose regimen, but also in predicting the possible side-effects.

Carbon monoxide (CO) poisoning may lead to hypoxic/anoxic injury and eventually ischemic encephalopathy. Magnetic resonance imaging (MRI) has a well-recognized role in assessment of the severity of brain damage caused by CO poisoning. In this study, we aimed to present and analyze the structural abnormalities in the brain MRI and especially in diffusion weighted MRI (DWI) images in a series of patients with acute CO poisoning. This cross-sectional observational study was performed on patients with moderate to severe CO poisoning admitted to Mashhad Medical Toxicology Center of Imam Reza Hospital, Mashhad, Iran, during autumn and winter 2013. After stabilization, patients underwent brain MRI. T1 weighted, T2 weighted and FLAIR images in sagittal, axial and coronal sections, and DWI in axial sections were performed for each patient. Eighteen patients (77.8% men) were enrolled in this study with median age of 29.5 years. Eleven patients (61.1%) had abnormal MRI signals and in 7 cases no abnormality or nonspecific abnormalities were detected. The most common involved region in brain MRI was white matter (38.9%) followed by globus pallidus (33.3%). Patients with signal abnormality in brain MRI had significantly longer duration of exposure to CO compared to those without signal changes (10.6 ± 6.2 h vs. 3.4 ± 2.8 h, P = 0.011). Nine patients had restricted diffusion in DWI. Patients with restricted diffusion in DWI had also longer duration of exposure to CO compared to patients with normal DWI (12.1 ± 5.5 h vs. 3.5 ± 2.9 h, P = 0.001). The white matter and globus pallidus were the most common affected regions in brain following acute CO poisoning. Signal abnormalities and restricted diffusion in MRI were correlated with duration of exposure to CO but not with the carboxyhemoglobin levels.

Copper sulfate ingestion is a relatively popular method for committing suicide in Indian subcontinent. It causes a high mortality rate, and so a growing concern has been raised to identify the severe alarming signs suggestive of poor prognosis and to improve treatment approaches. Case report: A 22-year-old unmarried man working as a painter was found unconscious at his friend residence. The patient developed hypotension, hemorrhagic gastroenteritis with hematemesis and melena, renal and hepatic failure, severe metabolic acidosis and intravascular hemolysis during admission at hospital. His signs were refractory to treatment with fluid replacement therapy, vasoactive drugs, antiemetic drugs, ranitidine, furosemide, methylene blue and 2,3 dimercaptopropane-1-sulphonate. He died six hours post-admission. In post-mortem examinations, there were multiple sub-pleural and sub-epicardial hemorrhages and the gastrointestinal mucosa was congested, hemorrhagic, and greenish blue in color. The liver, on histological examination, showed sub-massive hepatic necrosis. On toxicological analyses, copper sulfate was detected in preserved viscera and results for other heavy metals were negative. Hypotension, cyanosis, uremia and jaundice can be considered as signs of poor prognosis in copper sulfate poisoning. Copper sulfate ingestion is life-threatening due to its deleterious effects on the upper GI, kidneys, liver and blood. Having no time to waste, aggressive treatments should be immediately instituted and signs of poor prognosis should be kept in mind.