Because OP pesticides degrade quickly when exposed to air and light, they have been considered relatively safe to consumers. However, OP residues may linger on fruits and vegetables. Certain OP pesticides have been banned for use on some crops, For example, methyl parathion is banned from use on some crops and permitted on others. It can also occur through deliberate poisoning using nerve agents such as sarin and tabun. Examples
Insecticides including malathion, parathion, diazinon, fenthion, dichlorvos, chlorpyrifos, ethion, trichlorfon
Nerve agents including soman, sarin, tabun, VX
Herbicides including tribufos [DEF], merphos are tricresyl phosphate–containing industrial chemicals.Exposure to any of the above-listed organophosphates may occur through inhalation, skin absorption, and ingestion, most commonly of food that has been treated with an OP herbicide or insecticide. Exposure to these chemicals can occur at public buildings, schools, residential areas, and in agricultural areas. Chlorpyrifos and Malathion have been linked to reproductive effects, neurotoxicity, kidney/liver damage, and birth defects. Dichlorvos has also been linked to reproductive effects, neurotoxicity, and kidney/liver damage. It is also recognized to be a possible carcinogen. Pathophysiology
The health effects associated with organophosphate poisoning are a result of excess acetylcholine (ACh) present at different nerves and receptors in the body because acetylcholinesterase is blocked. Accumulation of ACh at motor nerves causes overstimulation of nicotinic expression at the neuromuscular junction. When there is an accumulation of ACh at autonomic ganglia synapses this causes overstimulation of muscarinic expression in the parasympathetic nervous system.
Diagnosis
Diagnosis is fourfold: History and physical examination, elevation of creatine kinase, electromyograph (EMG) alteration, and a positive muscle biopsy.The hallmark clinical feature of polymyositis is proximal muscle weakness, with less important findings being muscle pain and dysphagia. Cardiac and pulmonary findings will be present in approximately 25% of cases of patients with polymyositis.Sporadic inclusion body myositis (sIBM) is often misdiagnosed as polymyositis or dermatomyositis but it can be differentiated as myositis that does not respond to treatment is likely IBM. sIBM comes on over months to years; polymyositis comes on over weeks to months. Polymyositis tends to respond well to treatment, at least initially; IBM does not. Treatment
The first line treatment for polymyositis is corticosteroids. Specialized exercise therapy may supplement treatment to enhance quality of life. Epidemiology
Polymyositis strikes females with greater frequency than males. Polymyositis as a distinct diagnosis
The discovery of several myositis-specific autoantibodies during the past decades has enabled the description of other discrete subsets of diagnosis, specifically the discovery of Antisynthetase syndrome in reducing the number of diagnoses of polymyositis. Society and culture
Notable cases
Dan Christensen, painter of abstract art. Died due to heart failure caused by polymyositis. Robert Erickson, American composer and teacher who was a leading modernist exponent of "12-tone" composition. Died from the effects of polymyositis. David Lean, film director. Eric Samuelsen, playwright. Victor Manuel Resendiz Ruiz, wrestler. Cardinal John Wright

See also
Limb girdle syndrome

References


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