Agent: Ricin, a glycoprotein
toxin derived from castor plant beans, has great potential as a biological
agent due to its wide availability. The toxin is quite stable over long
periods of time.
Disease: Ricin intoxification
Incubation Period: 4-8 hours
Signs/Symptoms: Symptoms will depend on the dose and route of exposure.
Initial symptoms following inhalation include weakness, fever, cough,
dyspnea, nausea, chest tightness, and arthralgia. These are usually followed
by sweating, pulmonary edema, and cyanosis. Necrotizing, suppurative airway
lesions may be noted in conjunction with rhinitis and laryngitis. If left
untreated, respiratory failure and cardiovascular collapse due to inhalation
of the agent can lead to death after 36-72 hours.
Ingestion will be followed by rapid onset of nausea, vomiting, abdominal
cramps, and severe diarrhea. Other symptoms include fever, thirst, headache,
sore throat, and dilation of the pupils. Death may occur on the third day or
later and is usually due to vascular collapse.
Differential Diagnosis: For inhalational exposure, similar
symptoms in large numbers of patients might suggest several respiratory
pathogens. Influenza, Q fever, tularemia, plague, and respiratory illnesses
due to exposure to staphylococcal enterotoxin B (SEB) and chemical agents
such as phosgene should be included in the differential diagnosis. SEB
intoxication would likely have a more rapid onset and lower mortality. Acute
lung injury induced by phosgene would progress much faster that caused by
ricin. Nerve agent intoxication would be characterized by acute onset of
cholinergic crisis with dyspnea and profuse secretions.
The differential diagnosis for patients who have ingested ricin would
include disease due to all the major enteric pathogens. These should be
ruled out with culture.
Diagnostic Tests: Early postexposure (0-24 hours) nasal or throat
swabs and induced respiratory secretions may be collected for toxin assay.
Blood for serum may be collected in a tiger-top (SST) or red top tube. Toxin
assays and measurement of antibody response can be performed on serum.
Supportive Tests: Patients with aerosol exposure to ricin may have
bilateral infiltrates on chest x-ray, arterial hypoxemia, and neutrophilic
leukocytosis. A bronchial aspirate rich in protein compared to plasma is
characteristic of high permeability pulmonary edema. Endoscopic evaluation
may reveal necrotizing suppurative lesions in conjunction with tracheitis
Treatment: Management of patients is supportive. Acetaminophen for
fever, and cough suppressants may make the patient more comfortable.
Hydration is important. For those with pulmonary intoxification, respiratory
support may be necessary. Pulmonary edema may need to be treated with
positive end expiratory pressure ventilation and diuretics. Standard
management techniques for oral poisoning should be used if the toxin is
Infection Control/Decontamination: Standard precautions should be used
by healthcare workers. Decontaminate exposed skin by washing with soap and
water and/or 0.1% sodium hypochlorite (1 part household bleach added to 49
Report: Any suspect cases should be reported immediately to the local
health authorities (1-800-705-8868) and Poison Control at 1-800-764-7661.
Centers for Disease Control and Prevention,