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| wikitox:2.2.7.3.1_paraquat [2019/05/08 23:28] – [Qualitative urine test for paraquat] admin | wikitox:2.2.7.3.1_paraquat [2019/05/09 00:53] (current) – [Qualitative urine test for paraquat] admin | ||
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| ==== Metabolism - Elimination ==== | ==== Metabolism - Elimination ==== | ||
| - | Paraquat is rapidly distributed to lung, liver, kidney and muscle. It has a volume of distribution of 1.2–1.6 L/kg (Wunnapuk, 2014). The volume of distribution is large as it is concentrated inside cells, particularly pneumocytes. Distribution occurs rapidly with substantial distribution within the first few hours. During this period, concentrations of paraquat in lung tissue rise progressively to several times that of the plasma concentration. | + | Paraquat is rapidly distributed to lung, liver, kidney and muscle. It has a volume of distribution of 1.2–1.6 L/kg (Wunnapuk, 2014). The volume of distribution is large as it is concentrated inside cells, particularly pneumocytes. Distribution occurs rapidly with substantial distribution within the first few hours. During this period, concentrations of paraquat in lung tissue rise progressively to several times that of the plasma concentration. |
| ===== CLINICAL EFFECTS ===== | ===== CLINICAL EFFECTS ===== | ||
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| ==== Gastrointestinal effects ==== | ==== Gastrointestinal effects ==== | ||
| - | Concentrated paraquat (20%) is corrosive and has direct gastrointestinal toxicity leading to oesophageal and gastric erosion as well as burns in the mouth and throat. These corrosive effects are similar to that observed with alkali ingestion.\\ | + | Concentrated paraquat (20%) is corrosive and has direct gastrointestinal toxicity leading to oesophageal and gastric erosion as well as burns in the mouth and throat. These corrosive effects are similar to that observed with alkali ingestion. \\ Paraquat is rapidly distributed to lung, liver, kidney and muscle. It has a volume of distribution of 1.2–1.6 L/kg (Wunnapuk, 2014). The volume of distribution is large as it is concentrated inside cells, particularly pneumocytes. Distribution occurs rapidly with substantial distribution within the first few hours. During this period, concentrations of paraquat in lung tissue rise progressively to several times that of the plasma concentration. |
| - | Paraquat is rapidly distributed to lung, liver, kidney and muscle. It has a volume of distribution of 1.2–1.6 L/kg (Wunnapuk, 2014). The volume of distribution is large as it is concentrated inside cells, particularly pneumocytes. Distribution occurs rapidly with substantial distribution within the first few hours. During this period, concentrations of paraquat in lung tissue rise progressively to several times that of the plasma concentration. | + | |
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| ==== Multiorgan failure ==== | ==== Multiorgan failure ==== | ||
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| Plasma concentrations of paraquat are important indicators of prognosis. A plasma concentration > 5 mg/L at any time indicates an invariably fatal outcome. Nomograms have been developed which indicate the chance of survival. Paraquat blood concentrations are performed by the Princess Alexandra Hospital in Brisbane, Australia (and in some other institutions). | Plasma concentrations of paraquat are important indicators of prognosis. A plasma concentration > 5 mg/L at any time indicates an invariably fatal outcome. Nomograms have been developed which indicate the chance of survival. Paraquat blood concentrations are performed by the Princess Alexandra Hospital in Brisbane, Australia (and in some other institutions). | ||
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| ==== Paraquat Nomogram ==== | ==== Paraquat Nomogram ==== | ||
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| ==== Qualitative urine test for paraquat ==== | ==== Qualitative urine test for paraquat ==== | ||
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| * 1 mL of a 1% sodium dithionate solution (found in haematology labs) is added to 10 mL of urine. | * 1 mL of a 1% sodium dithionate solution (found in haematology labs) is added to 10 mL of urine. | ||
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| A blue colour change indicates paraquat ingestion. If this test is negative on urine passed 2 to 6 hours after ingestion it indicates that a significant exposure is unlikely. | A blue colour change indicates paraquat ingestion. If this test is negative on urine passed 2 to 6 hours after ingestion it indicates that a significant exposure is unlikely. | ||
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| * Paraquat concentration > 3–5 mg/L | * Paraquat concentration > 3–5 mg/L | ||
| - | The presence of these indicates a fatal outcome in the majority of patients. \\ \\ The rate of increase in plasma creatinine over time (5 hours) is also correlated with outcome and can give prognostic information (Ragoucy-Sengler C and Pileire B, 1996). \\ It is also possible to predict the probability of survival for any specified time and concentration after ingestion of paraquat up to at least 200 h after ingestion (Jones AL et al, 1999). \\ \\ The time course of the rise in blood lactate can also help in predicting outcome in the absence of paraquat concentrations (Sun, 2014) | + | |
| ===== TREATMENT ===== | ===== TREATMENT ===== | ||