Clinical and pathological profile of paraquat poisoning cases - A cross-sectional study in Odisha, India

Abstract

Agriculture being the primary mode of occupation in Odisha leads to the rampant and widespread use of chemical pesticides and herbicides. Paraquat is a widely used herbicide. Ingestion of PQ irrespective of the quantity could be fatal with life-threatening effects on the gastrointestinal (GI) tract, kidney, liver, lungs, and other organs. Death is usually associated with respiratory insufficiency due to an oxidative insult to the Type-II alveolar epithelium with subsequent fibrosis.All cases of paraquat ingestion coming to AIIMS, Bhubaneswar casualty from July 2020 to November 2020 were studied for their clinical findings. The fatal cases were subjected to autopsy and findings noted.Men were most commonly involved. All of the patients had self-harm intent while consuming. The most common presenting symptoms were difficulty in swallowing, Respiratory system was most commonly affected. The cause of death was attributed to respiratory and multi-organ failure.Paraquat is widely marketed for its efficacy and low environmental toxicity. Lack of a specific antidote increases the fatality. The most common cause of death is respiratory failure. Paraquat causes renal failure by causing hypovolemia, circulatory failure, septicemia, and direct toxicity. The mainstay of treatment is supportive though the use of immune-suppressants has shown some positive results.

Diagnosis and Management of Paraquat Intoxication

“…Oral paraquat bioavailability varies, also estimated to be below 5-10% within one to six hours. 6,[20][21][22] Most paraquat poisoning is caused by accidental or intentional oral ingestion. Jejunum is the main pathway for the absorption of paraquat after oral after peak plasma time (Tmax) to much lower levels.…”

“…This causes a small portion of paraquat which is distributed to deeper tissues, to be eliminated slowly by the kidneys for days to weeks. 6,13,22 Paraquat accumulates in the lungs mainly through active transfer and polyamine transporters. These polyamine transporters are mainly involved in the 3482 transport of polyamines such as spermine, spermidine, and putrescine.…”

“…21 Apart from being an important place for enzymatic metabolism and detoxification, the liver is also responsible for metabolizing some of the paraquat shown to be slower than in animals since it was detected in the urine, 7 days to 26 days after ingestion. 13,22 Biliary elimination may also represent an important excretory pathway due to the strong expression of Pglycoprotein (P-gp) in the hepatocyte canalicular membrane. Studies show that paraquat is secreted from the liver into the duodenum, then reabsorbed into the intestinal epithelial cells.…”

“…This is due to the rapid and excessive proliferation and differentiation of fibroblasts, which results in loss of lung architecture. 22,24 The main pathogenesis of lung damage is the result of the formation of free radicals with oxidative damage to lung tissue. Acute pulmonary edema and lung damage occur within hours due to heavy exposure.…”

Diagnostic Dilemma in Fatal Paraquat Poisoning: An Autopsy Case Report

“…Paraquat poisoning has a high death rate since it is extremely toxic, and there are no standard management protocols or antidotes that work. Irrespective of the quantity consumed, Paraquat is known to inflict lethal effects on the lungs, gastrointestinal system, kidneys, and various other organs (3).…”