Israel Medical Association Journal

Organophosphate and carbamate are mainly used to kill insects, thereby protecting livestock, crops, homes and communities. Yet, these compounds also convey great danger. OP[1] and CRB[2] poisoning is an important clinical problem, often life-threatening, especially in the pediatric population in rural areas where reaching a physician or hospital on time is difficult. We present a summary of accumulated toxicological knowledge as well as clinical and laboratory experience from a medical center serving a relatively vast rural area and pediatric population. We stress the importance of knowing how to recognize the classic signs of OP and CRB poisoning and when it is appropriate to investigate for such poisoning even in the absence of those signs. Like any medical emergency, OP and CRB poisoning requires prompt resuscitation and use of antidotes. Atropine, oxygen and fluids are the mainstay of therapy. Oximes, which were found useful in some cases of OP poisoning and useless in some cases of CRB poisoning, are absolutely safe as empiric treatment, which is often needed since the major differential diagnosis of OP poisoning is CRB poisoning that is clinically indistinguishable. We hope that continuing research will offer further insights into the management of such events, and we are confident that improved medical management of OP and CRB poisoning will result in a reduction of morbidity and other complications associated with intensive care procedures and hospitalization. 

Background: Sulfur mustard and VX are potent chemical warfare agents that penetrate rapidly through the skin, causing severe prolonged injuries and sometimes death.

Objectives: To develop a topically applied pretreatment that will act as a barrier and prevent the absorption of these agents through the skin, reducing morbidity and saving life.

Methods: Several formulations were developed and tested in preclinical animal studies in pigs. The protecting cream was applied as a single application (0.5–1 ml/100 cm²) prior to exposure (10 minutes to 12 hours) to sulfur mustard or VX. Assessment of sulfur mustard-induced skin damage was based on clinical and histologic evaluations. When tested against VX, clinical signs and blood cholinesterase activity were monitored. At the final stage of development, safety studies were conducted in animals and in human volunteers.

Results: The formulation that gave the best results, coded IB1 (under patent application), provided significant protection against a 1 hour exposure to sulfur mustard (droplets or vapor). All the pigs pretreated with IB1 cream survived a 1–4 hour challenge of 2xLD₅₀ VX and did not exhibit any overt clinical signs. Protection was exhibited even when the cream was applied 12 hours (single application) prior to exposure. IB1 was found to be non-irritating in animals and humans. No adverse effects were found in a Phase I clinical study in young healthy volunteers when the cream was applied to around 20% of the skin surface (results presented elsewhere).

Conclusions: IB1 cream has been shown to be a safe and effective topical skin protectant against the chemical warfare agents sulfur mustard and VX.

Atropine is the drug of choice for treatment of organophosphate (OP) nerve agent and insecticide intoxication and has been used for this indication for several decades. Adverse reactions to atropine may occur, and are of two types: toxic and allergic. Toxic reaction, the most common form, results from the anti-muscarinic effects of the drug. Since it is most probably related to interpersonal variation in sensitivity to atropine, toxic effects may appear at the usual therapeutic doses. The second type, allergic reaction, includes local manifestations, usually after the administration of eyedrops, and systemic reaction in the form of anaphylaxis. Since most patients manifest only a mild reaction, allergy testing is not performed and the prevalence of allergy to atropine is therefore not known. Severe allergic reaction to atropine is rare, as evidenced by the small number of case reports in the literature despite the drug's extensive use. Alternative anti-muscarinic drugs recommended for OP poisoning include glycopyrrolate and scopolamine. Glycopyrrolate is a peripheral anti-muscarinic drug that has been studied in comparison to atropine for many clinical indications, while scopolamine is an anti-muscarinic drug with both peripheral and central effects. An acceptable alternative regimen for patients with proven allergy to atropine is a combination of glycopyrrolate with centrally active drugs such as benzodiazepines or scopolamine.

Background: Organophosphates (OP) are frequently used as insecticides in the household and in agricultural areas, thus posing a risk for accidental exposure.

Objectives: To describe the characteristics, clinical course and outcome of 97 patients admitted to emergency rooms with a diagnosis of acute OP poisoning.

Methods: The clinical details of 97 patients were collected from 6 different hospitals in Israel. Diagnosis of intoxication was based on clinical findings, butyrylcholinesterase levels and, in several cases, the material brought to the hospital. Demographic, intoxication and clinical data were analyzed.

Results: The study group comprised 64 men and 33 women whose age range was 1–70 years old (mean 19.8 ± 17.1); more than one-third of the patients were less than 10 years old. Accidental exposure was the cause of intoxication in 51.5% of the patients, and suicide in 20.6% of exposures. Intoxication occurred at home in most patients (67%), and the route of intoxication was oral in 65% of them. The patients arrived at the hospital 20 minutes to 72 hours after intoxication. Nine patients were asymptomatic; 53 presented with mild intoxication, 22 with moderate, and 13 had severe intoxication, 5 of whom died. There was a direct correlation between the degree of inhibition of butyrylcholinesterase levels and the severity of intoxication. Treatment included decontamination and antidotal medication. Duration of hospitalization ranged between 1 and to 14 days (average 2.9 days).

Conclusions: Organophosphates may cause severe morbidity and mortality. Medical staff should therefore be aware of the clinical manifestations and the antidotal treatment for this poisoning.