Paraquat Intoxication – experience of an Internal Medicine ward for 18 years

Abstract

Introduction: Paraquat is a contact herbicide commercially available since 1962. Paraquat intoxication (PI) is usually voluntary
and highly lethal, since there is no effective antidote. Toxicity
occurs through cyclic redox reactions, damaging mainly the
kidneys and lungs.
Aim, material and methods: featuring the clinical presentation,
management and outcome of patients with PI over an 18 years
period (from the 01st January 1993 to the 31st December 2010)
through the retrospective analysis of clinical files and comparing
the survivors and the deceased.
Results: Thirty-one cases of Paraquat intoxication were included, with a male: female ratio 1:1. Age range from 13 to 80 years,
mean age 42.4years (±18.7).All intoxications were voluntary and
by oral route. There was statistical difference in the amount ingested (22.1 mL vs. 72.7 mL, p<0.0005). A non-significant trend
to a longer delay until getting medical attention in the deceased
group (1.6 h vs. 3.2 h, p=0.091). Statistical significance was found
between mortality and leukocytosis, hypocapnea, hypoxemia, LDH,
alkaline phosphatase and AST. There was no difference between
groups according to treatment options, although hemocarboperfusion was used more often in the deceased group (53.9%
vs. 66.7%, p=0.471) and corticosteroids in the survivor group
(61.5% vs. 44.4%, p=0.350). Mortality rate was 58.1% (66.7%
in the first 72 hours), due to respiratory insufficiency and multiple
organ failure. Variable levels of pulmonary fibrosis occurred in
38.5% of the survivors.
Discussion & Conclusion: Paraquat intoxication has a poor
prognosis with limited efficiency of treatment approaches. The
relation between Paraquat in the urine and the time elapsed after
ingestion is the main determinant factor in the prognosis. In this
study the presence of dyspnea, hypocapnea and hypoxemia was
linked to a bad prognosis. There was no statistical difference
between the available treatment options.