Abstract              Background: Organophosphate (OP) pesticide poisoning is a major challenging public-health problem in India. An early diagnosis and treatment is of utmost importance in OP poisoning in order to reduce mortality. Knowledge of factors predicting mortality help in reducing the deaths due to OP poisoning. The current study was aimed to investigate the factors predicting mortality in organophosphorus poisoning. Material and Methods: A total of 50 cases, above the age of 13 years with history of exposure to insecticide with characteristic clinical manifestations of insecticide poisoning were included in the study. Information was collected by interviewing patients / their relatives regarding type of poison, amount of poison, time since poisoning, food and/or alcohol consumption. Results: Most vulnerable age group was between 21-30 years (46%) and male to female ratio was 1.27:1. Out of 50 patients 3 patients expired. Mortality was highest in chlorpyriphos (66.7%) followed by parathion (33.3%) andin patients who did not took food before ingestion of OP compound. Mortality was significantly higher in those patients hospitalized two or more hours after ingestion of OP compound. Discussion: Independent predictors of mortality in patients with OP poisoning were found to be nature of OP compound, delay in time of hospitalization and amount of ingestion of compound. Knowledge of these findings which may contribute to mortality help in detecting high-risk patients in the emergency room.

Key Words: Organophosphates, poisoning, mortality, hospitalization.

 

INTRODUCTION

Organophosphate (OP) compounds are widely used as pesticides in agricultural parts of the world. OP pesticide poisoning is a major challenging public-health problem in developing countries of Asia like India and Sri Lanka^1,2. WHO estimates that three million cases of poisoning occur worldwide and the incidence of pesticide poisoning in developing countries has doubled during the past 10 years³. The widespread form of OP poisoning is suicidal attempt^1,4. Intentional poisoning with OP was reported as 65-79.2% in developing countries^5,6. It is a major cause of morbidity and mortality especially in patients admitted to the intensive care unit (ICU). In hospital based studies of India, mortality rates associated with pesticides have been reported to be as high as 50–70%⁷. Early identification followed by effective management in the initial stages increases the rate of survival among OP poisoning patients. Recent studies suggest that red cell acetylcholinesterase (AChE) activity accurately correlates with AChE activity at the synapse and it will be good marker of severity in initial stages of poisoning. However, serial measurements of cholinesterase for the prognosis of OP poisoning are still controversial. It depends on the poison load, aging of AChE enzymes, nature of OP compounds etc. A study conducted in St. John's Medical College, Bangalore suggested that the correlation between serial measurements of cholinesterase level with prognosis of OP poisoning does not have any significance⁸. Cardiac manifestations are often the cause of serious complications or fatality. Although mortality in OP poisoning depends on the amount of the ingested substance, other predicting factors such as type of poison, time since poisoning, food and/or alcohol consumption, respiratory support, intubation and separation from the ventilator also playa vital role. Therefore, an early diagnosis and treatment is of utmost importance in OP poisoning in order to reduce mortality. The current study was aimed to investigate the factors predicting mortality in organophosphorus poisoning.

 

MATERIAL AND METHODS

This cross sectional study was conducted over a period of two years from January 2016 to January 2017on patients with insecticide poisoning admitted to department of Medicine in tertiary care centre hospital. Patients above the age of 13 years with history of exposure to insecticide with characteristic clinical manifestations of insecticide poisoning were included in the study. Whereas, patients with known cardiac illness, mixed poisoning with other substances and with doubtful diagnosis were excluded from the study. Information was collected by interviewing patients / their relatives. History was taken in detail regarding type of poison, amount of poison, time since poisoning, food and/or alcohol consumption. Complete clinical examination was done. All routine laboratory investigations like complete blood count, urine examination, random blood sugar, blood urea, creatinine, Chest X - ray, Serum calcium and potassium were done wherever required. Patients were evaluated for standard 12 lead Electrocardiogram (ECG) at the time of admission as early as possible and at time of discharge.

 

RESULTS

In present study, 50 cases of OP poisoning were admitted during the study period. Mean age of patients was 35.32±18.63. Maximum number of patients i.e., 16 (32%) of patients were in the age group of 21-30 years followed by 12 (24%) of the patients were in the age group of 11-20 years. Out of 50 patients, 28 (56%) of patients were male and 22 (44%) were female with male: female ratio of 1.27:1 (Table 1).

 

Table 1: Demographic characteristics of patients studied

Demographic data	No. of patients
Age groups (years) 11-20 21-30 31-40 41-50 51-60 >60 Sex Male Female	12 (24%) 16 (32%) 07 (14%) 04 (8%) 05 (10%) 06 (12%)   28 (56%) 22 (44%)

  

Table 2: Characteristics of intoxication

42% of patients had ingested chlorpyriphos while 18% of patients took dichlorvos. 32%of patients had ingested between101-200 ml. 30% of patients had ingested 210-300 ml. Only 4% of patients reached the hospital within half an hour of ingestion of OP poison. 72% of patients ingested OP poison without food and only 28% of patients ingested with food. 64% of patients ingested OP poison without alcohol consumption and 36% of patients ingested with alcohol (Table 2).

 

Table 3: Age distribution of patients studied

In our study mortality was highest in age group of 11-20 (66.7%) followed by age group of 31-40 (33.3%) but this value is not statistically significant (P=0.923).When mortality is compared between male and females, mortality in females is 66.7% and in males is 33.3%, which is statistically significant (P<0.001). According to ingestion of compound, mortality was highest in chlorpyriphos (66.7%) followed by parathion (33.3%) which is not statistically significant (P=0.904). According to amount of poison mortality was highest in patients who ingested the compound more 100 ml which is not statistically significant (P=1.000). Mortality was highest in patients who did not took food before ingestion of OP compound (100%) as compared with those who had food before ingestion of OP compound (0%) which is statistically significant (P<0.001). It may be because food interfering the absorption of OP compound when taken together. In present study, only 4% of patients reached the hospital within half an hour of ingestion of OP poison and mortality was 0%, 50% of patients reached hospital within one hour and mortality was 33.7%, 45% of patients reached to hospital within 2 hours of ingestion and mortality was 66.7%.Mortality was significantly higher in those patients hospitalized two or more hours after ingestion of OP compound. In our study, mortality rate (4%) was least among the patients who presented earliest as compared to who presented later. This shows relation between delay in hospitalization and increase in mortality.

 

DISCUSSION

In present study, maximum incidence of organophosphorus poisoning was among the age group of 21-30 years of age (32%) which is comparable to all other studies. In Goel A et al⁹, maximum incidence was among the 12-30 years of age (86.4%), Karaa IH et al¹⁰ was among 21-30 years of age (83.3%), Agarwal SB et al¹¹ with the maximum number of cases in the age group 21–30 years. Incidence of organophosphorus poisoning was more common in males which is comparable to reports of all other studies. This can be because of males are more exposed to stress in society as they are earners of family mostly and easy accessibility of OP compounds to them. In the present study, 44% of patients were female and 56% of patients were male withmale: female ratio of 1.27:1. In Laudari S et al¹², 40.2% of patients were female and 59.87% of patients were male.In a study by Goel A et al⁹, 28.15% of patients were female and 71.85% of patients were male. Karaa IH et al¹⁰ observed that 9 of patients were female and 5 of patients were male. Yurumez Y et al¹³ found 59.5% female and 40.5% male withmale: female ratio of 1:1.46.  In the present study 42% of patients had ingested chlorpyriphos. In a study of Goel A et al⁹, 26.21% of patients had ingested monocrotophos, 8.47% of patients ingested dimethonate, 7.76% of patients had ingested parathion and 15.3% of malathion. In study of Avasthi G et al¹⁴, 41.3% of patients had ingested monocrotophos, 13.8% of patients ingested dimethonate, 6.9% of patients had ingested parathion and 17.24% of malathion. Chlorpyriphos was commonest agent used in present study as compared to Goel A et al [9] and Avasthi G et al¹⁴ where monocrotophos was commonest agent used. Thus, variability in most commonly used compound can be because of local availability of compounds for agricultural use in that area. Mortality was highest with chlorpyriphos (66.7%) than other agents used. However, this difference was not found to be statistically significant. This may be because of variable toxicity of the compound. In present study, mortality rate of 4% was least among the patients who presented earliest as compared to who presented later. This shows relation between delay in hospitalization and increase in mortality. In study of Goel A et al⁹, only 14.56% of patients reached the hospital within 0-2 hours of ingestion of OP poison, 54.37% of patients reached hospital within 2-4 hour, 31.6% of patients reached to hospital within more than four hours of ingestion. So, in above study mortality was significantly higher in those patients who hospitalized two or more hours after ingestion of compound. Mortality was higher in females as compared to males which is statistically significant finding in our study.Independent predictors of mortality in patients with OP poisoning were found to be nature of OP compound, delay in time of hospitalization and amount of ingestion of compound. Knowledge of these findings which may contribute to mortality help in detecting high-risk patients in the emergency room.

 

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