Poisoning - Pesticides (Paraquat)

Emergency Medicine

Clinicals - History

Fact Explanation
Pain and swelling of the mouth and throat When large amounts are swallowed pain and swelling of the mouth and throat occur immediately after the ingestion. Pain and swelling of the mouth and throat
When large amounts are swallowed pain and swelling of the mouth and throat occur immediately after the ingestion.
Nausea and or vomiting This is common after oral ingestion. Nausea and or vomiting
This is common after oral ingestion.
Abdominal pain Ingested paraquat causes mucosal inflammation and may lead to intestinal perforation. Abdominal pain
Ingested paraquat causes mucosal inflammation and may lead to intestinal perforation.
Diarrhea Diarrhea is sometimes bloody. Diarrhea
Diarrhea is sometimes bloody.
Seizures Due to involvement of the central nervous system. Seizures
Due to involvement of the central nervous system.
Confusion Patients can have confusion and or coma. Confusion
Patients can have confusion and or coma.
Symptoms of heart failure When small amounts are ingested, patients may not present with above acute symptoms, instead they present might present with symptoms of heart failure later. symptoms of heart failure include, reduced exercise tolerance, orthopnea, paroxysmal nocturnal dyspnea, and dependent edema. Symptoms of heart failure
When small amounts are ingested, patients may not present with above acute symptoms, instead they present might present with symptoms of heart failure later. symptoms of heart failure include, reduced exercise tolerance, orthopnea, paroxysmal nocturnal dyspnea, and dependent edema.
Symptoms of renal failure Renal failure can result secondary to dehydration in the acute setting. Renal failure can also be a late presentation in patients who have ingested a small amount of paraquat. Symptoms of renal failure
Renal failure can result secondary to dehydration in the acute setting. Renal failure can also be a late presentation in patients who have ingested a small amount of paraquat.
Symptoms of liver failure Acute liver failure can occur if the patient has ingested a large amount. Liver failure can also manifest as a late complication of ingestion of a small amount of paraquat. Jaundice is a possible presentation. Symptoms of liver failure
Acute liver failure can occur if the patient has ingested a large amount. Liver failure can also manifest as a late complication of ingestion of a small amount of paraquat. Jaundice is a possible presentation.
Symptoms of lung fibrosis Pulmonary fibrosis is a known late complication of paraquat poisoning and occurs after 2 to 6 days of ingestion of a small amount. Patients develop dyspnea. Symptoms of lung fibrosis
Pulmonary fibrosis is a known late complication of paraquat poisoning and occurs after 2 to 6 days of ingestion of a small amount. Patients develop dyspnea.
Death Patients can be dead at the time of presentation if a large amount is ingested. This is usually secondary to multi-organ failure. Death
Patients can be dead at the time of presentation if a large amount is ingested. This is usually secondary to multi-organ failure.
People who are at risk of suicide Self poisoning is commonly seen in patients with depression or patients who have acute stressful life events. People who are at risk of suicide
Self poisoning is commonly seen in patients with depression or patients who have acute stressful life events.

Clinicals - Examination

Fact Explanation
Assessment of the airway, breathing and circulation At the time of presentation patency of the airway should be assessed. Observe for the presence of spontaneous breathing movements. Pulse and blood pressure is measured to assess the adequacy of circulation. Assessment of the airway, breathing and circulation
At the time of presentation patency of the airway should be assessed. Observe for the presence of spontaneous breathing movements. Pulse and blood pressure is measured to assess the adequacy of circulation.
Respiratory rate Respiratory rate is low in patients with respiratory failure. Respiratory rate
Respiratory rate is low in patients with respiratory failure.
Pulse Patients with dehydration can have low volume pulse and tachycardia. Pulse
Patients with dehydration can have low volume pulse and tachycardia.
Blood pressure If the patients are dehydrated, they can have low blood pressure. Blood pressure
If the patients are dehydrated, they can have low blood pressure.
Signs of dehydration Patients can develop signs of dehydration secondary to severe vomiting and diarrhea. Dry skin, dry mucous membranes, reduced skin turgor, reduced urine output and sunken eyes are clinical signs of dehydration. Signs of dehydration
Patients can develop signs of dehydration secondary to severe vomiting and diarrhea. Dry skin, dry mucous membranes, reduced skin turgor, reduced urine output and sunken eyes are clinical signs of dehydration.
Paraquat tongue This is mucosal edema of the tongue which progress to ulceration and bleeding, and seen in oral ingestion of paraquat. Paraquat tongue
This is mucosal edema of the tongue which progress to ulceration and bleeding, and seen in oral ingestion of paraquat.
Signs of pulmonary fibrosis Pulmonary fibrosis leads to clubbing, cyanosis, dyspnea and localized crackles. Signs of pulmonary fibrosis
Pulmonary fibrosis leads to clubbing, cyanosis, dyspnea and localized crackles.

Investigations - Diagnosis

Fact Explanation
Analysis of urine for the presence of paraquat This is diagnostic of paraquat poisoning. This test is also done to estimate the prognosis as well. Analysis of urine for the presence of paraquat
This is diagnostic of paraquat poisoning. This test is also done to estimate the prognosis as well.
Estimation of plasma levels of paraquat Presence of more than 1.6 pg/ml paraquat after 12 hours of ingestion is invariably fatal. Estimation of plasma levels of paraquat
Presence of more than 1.6 pg/ml paraquat after 12 hours of ingestion is invariably fatal.

Investigations - Management

Fact Explanation
Chest X-ray Initially pulmonary edema is seen. Diffuse consolidation of the lungs become cystic lesions and finally result in lung fibrosis. Chest X-ray
Initially pulmonary edema is seen. Diffuse consolidation of the lungs become cystic lesions and finally result in lung fibrosis.
Pulse oxymetry Respiratory depression can cause hypoxia and hypercapnea. Pulse oxymetry
Respiratory depression can cause hypoxia and hypercapnea.
Arterial blood gas analysis Respiratory acidosis is seen in respiratory depression. Arterial blood gas analysis
Respiratory acidosis is seen in respiratory depression.
Serum electrolytes Electrolyte abnormalities can occur with significant fluid loss. Serum electrolytes
Electrolyte abnormalities can occur with significant fluid loss.
Liver transaminases Elevated in liver failure. Liver transaminases
Elevated in liver failure.
Serum bilirubin Elevated in liver failure. Serum bilirubin
Elevated in liver failure.

Management - Supportive

Fact Explanation
Health education People who are at risk of paraquat poisoning should be advised to use personal protective equipment while handling paraquat. If paraquat poisoning is suspected patients should be advised to seek immediate health care.
Paraquat and other pesticides should be stored in a safe place where children are unable to reach.
Health education
People who are at risk of paraquat poisoning should be advised to use personal protective equipment while handling paraquat. If paraquat poisoning is suspected patients should be advised to seek immediate health care.
Paraquat and other pesticides should be stored in a safe place where children are unable to reach.
Basic life support Management of the airway by insertion of an oropharyngeal airway or with tracheal intubation should be done if the airway is threatened. Oxygen should be delivered via a face mask or via the endotracheal tube if the patient is having severe hypoxia. (Higher concentrations of oxygen should not be used as this can increase the oxidative damage to the lungs.) Patients require intravenous fluid to correct any fluid deficit. In patients with shock a fluid bolus of 15–20 ml kg−1 over 15–30 min can be administered and repeated if the blood pressure is remaining low. Insertion of a nasogastric tube will prevent aspiration in patients with vomiting. Basic life support
Management of the airway by insertion of an oropharyngeal airway or with tracheal intubation should be done if the airway is threatened. Oxygen should be delivered via a face mask or via the endotracheal tube if the patient is having severe hypoxia. (Higher concentrations of oxygen should not be used as this can increase the oxidative damage to the lungs.) Patients require intravenous fluid to correct any fluid deficit. In patients with shock a fluid bolus of 15–20 ml kg−1 over 15–30 min can be administered and repeated if the blood pressure is remaining low. Insertion of a nasogastric tube will prevent aspiration in patients with vomiting.

Management - Specific

Fact Explanation
Remove all the clothes of the patient Paraquat is absorbed through inhalation and via the skin. Further absorption of paraquat can be prevented by removing the patient's clothes. Clothes are better removed by cutting them rather removing over the head. Remove all the clothes of the patient
Paraquat is absorbed through inhalation and via the skin. Further absorption of paraquat can be prevented by removing the patient's clothes. Clothes are better removed by cutting them rather removing over the head.
Wash with soap and water All the areas which is in contact with paraquat should be washed with soap and water. If there is any possibility of contact with eyes, wash the eyes with running water for 10 to 15 minutes. Wash with soap and water
All the areas which is in contact with paraquat should be washed with soap and water. If there is any possibility of contact with eyes, wash the eyes with running water for 10 to 15 minutes.
Activated charcoal This is useful if he patient has ingested paraquat. Administration of activated charcoal (Fuller’s earth) orally will bind with ingested paraquat and minimize its absorption. Activated charcoal
This is useful if he patient has ingested paraquat. Administration of activated charcoal (Fuller’s earth) orally will bind with ingested paraquat and minimize its absorption.
Vitamin C and E These act as antioxidants and minimize the free radical injury to lungs. Vitamin C and E
These act as antioxidants and minimize the free radical injury to lungs.
Steroids Methylprednisolone or dexamethasone pulses are used with vitamin C and E, which can further reduce the free radical damage. Steroids
Methylprednisolone or dexamethasone pulses are used with vitamin C and E, which can further reduce the free radical damage.
Cyclophosphamide Cyclophosphamide and steroid pulses prevent the lung injury and pulmonary fibrosis. Cyclophosphamide
Cyclophosphamide and steroid pulses prevent the lung injury and pulmonary fibrosis.
Hemodialysis Hemodialysis helps to filter out paraquat from the plasma. Hemodialysis
Hemodialysis helps to filter out paraquat from the plasma.
Lung transplantation Patients who develop pulmonary fibrosis may benefit from lung transplantation. Lung transplantation
Patients who develop pulmonary fibrosis may benefit from lung transplantation.

Concise, fact-based medical articles to refresh your knowledge

Access a wealth of content and skim through a smartly presented catalog of diseases and conditions.

  1. Facts About Paraquat. Centers for Disease Control and Prevention. [online] [viewed 11 June 2014] Available from: http://www.bt.cdc.gov/agent/paraquat/basics/facts.asp
  2. GAWARAMMANA IB, BUCKLEY NA. Medical management of paraquat ingestion Br J Clin Pharmacol [online] 2011 Nov, 72(5):745-757 [viewed 12 June 2014] Available from: doi:10.1111/j.1365-2125.2011.04026.x
  3. HUDSON M, PATEL S B, EWEN S W B, SMITH C C, FRIEND J A R. Paraquat induced Pulmonary fibrosis in three survivors. Thorax [online] 1991;46:201-204 [viewed 13 June 2014] Available from: http://thorax.bmj.com/content/46/3/201.full.pdf
  4. KERVéGANT M, MERIGOT L, GLAIZAL M, SCHMITT C, TICHADOU L, DE HARO L. Paraquat Poisonings in France during the European Ban: Experience of the Poison Control Center in Marseille J Med Toxicol [online] 2013 Jun, 9(2):144-147 [viewed 11 June 2014] Available from: doi:10.1007/s13181-012-0283-6
  5. RAGHU KONDLE, MAHESH VIDAVALUR, SASIDHAR PARRI, REDDY POLAMR, VENKATARAMANIAH VAJJA, AGRAWAL AMIT. Paraquat poisoning: A case report and review of literature. J Fam Community Med [online] 2013 December [viewed 13 June 2014] Available from: doi:10.4103/2230-8229.122023
  6. SEOK SJ, GIL HW, JEONG DS, YANG JO, LEE EY, HONG SY. Paraquat Intoxication in Subjects Who Attempt Suicide: Why They Chose Paraquat Korean J Intern Med [online] 2009 Sep, 24(3):247-251 [viewed 13 June 2014] Available from: doi:10.3904/kjim.2009.24.3.247