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Ricin: Clinical Description


  • Initial manifestation of symptoms related to poisoning is likely to occur within 4 to 10 hours following ingestion, within 4-8 hours following inhalation and within 12 hours following injection.
  • After ingestion of ricin it is extremely unlikely that signs and symptoms of poisoning would begin more than 10 hours after exposure.
  • After inhalational exposure to ricin powder, it is very unlikely that signs and symptoms of poisoning would begin more than 24 hours after exposure.

Signs and Symptoms of Ricin Poisoning by Route of Exposure

  • Systemic effects of ricin poisoning depend upon route of exposure and dose.
  • Dermal and ocular exposure by ricin in powder or mist form can cause erythema and pain of the skin and eyes.
  • Ingestion Exposure:
    • Signs and symptoms of poisoning from oral exposure to purified ricin are presumed to be similar to reports of illness after castor bean mastication and ingestion.
    • Some or all of the following signs and symptoms may be manifest:
      • Hallucinations
      • Hematuria
      • Hypotension
      • Hypovolemic shock, and multiple system organ failure may occur, leading to death
      • Influenza-like symptoms: fever, myalgia, and arthralgia
      • Profuse diarrhea (bloody or non-bloody)
      • Profuse vomiting
      • Seizures
      • Severe dehydration
      • Weakness.
  • Inhalational Exposure:
    • Data on inhalational exposure to ricin in humans are limited.
    • Some or all of the following symptoms may be manifest:
      • Cough, respiratory distress, bronchoconstriction
      • Cyanosis
      • Excessive diaphoresis
      • Hypotension, respiratory failure and multisystem organ failure may occur, leading to death
      • Influenza-like symptoms: fever, myalgia, and arthralgia
      • Nausea
      • Pulmonary edema
      • Weakness.
    • Persons exposed to castor bean dust in or around castor oil processing plants have been reported to manifest signs and symptoms of an allergic-like syndrome. Repeated inhalational exposures to sub-lethal amounts of ricin have resulted in:
      • Allergic syndrome with congestion of nose and throat
      • Chest tightness
      • Hives
      • Itchy, watery eyes
      • Wheezing, in severe cases.
  • Injection Exposure (data are limited):
    • In a single human trial of low doses of intravenous ricin, influenza-like symptoms of fatigue and myalgia occurred.
    • A case in which a person was injected with castor bean extract subcutaneously resulted in hospitalization 36 hours after the injection. Clinical manifestations of poisoning included:
      • Anuria and hypotension.
      • Complaints of nausea, weakness, dizziness, and myalgia.
      • Hepatic failure, renal failure, cardiorespiratory failure, and death 18 hours following admission.
    • In a case in which a dissident was thought to have been assassinated with a ricin injection, clinical manifestations ¬†of poisoning included:
      • Fever and vomiting that developed within 24 hours, followed by shock and multi-organ failure, and death within 3 days.
      • Pain at injection site, which developed immediately.
      • Weakness that developed within 5 hours.
    • In a case in which a chemist extracted ricin from a castor bean and self-administered injections of it, signs and symptoms of poisoning included:
      • Nausea, anorexia, mild elevation of liver function tests, and tissue damage at injection site.
      • Signs and symptoms persisted for 8 to 10 days.

General Signs and Symptoms of Ricin Poisoning (dependent on route of exposure)

  • Gastrointestinal System:
    • Abdominal pain
    • Abnormal liver function tests
    • Diarrhea (bloody or non-bloody)
    • Multiple ulcerations and hemorrhages of gastric and small-intestinal mucosa on endoscopy
    • Vomiting.
  • Respiratory System:
    • Bronchoconstriction (chest tightness)
    • Cough
    • Dyspnea
    • Hypoxemia
    • Non-cardiogenic pulmonary edema.
  • Skin and Mucous Membrane:
    • Erythema and pain of eyes and skin.
  • Systemic:
    • Dehydration
    • Fatigue
    • Fever
    • Muscle pain
    • Weakness.
  • Other Organ System:
    • Nervous System: Seizures (uncommon)
    • Cardiovascular: hypovolemic shock.
  • Manifestation of aforementioned signs and symptoms does not necessarily mean that a person has been exposed to ricin.
  • Death from ricin poisoning can occur within 36 to 72 hours of exposure.

For additional information

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