Ricin signs/symptoms

Diagnosis If signs and symptoms spelled out above are noted in large numbers of geographically clustered patients, exposure to aerosolized ricin is the suggested cause. The rapid time course of severe symptoms and death would be unusual for infectious agents. Laboratory findings are nonspecific except for specific serum ELISA (enzyme-linked immunosorbent assay). Acute and convalescent sera (plural of serum ) should be collected. 

Caution Ricin is extremely toxic to cells and acts by inhibiting protein synthesis. After aerosol exposure, signs and symptoms would depend on the dose inhaled. Humans can be expected to develop severe lung inflammation with progressive cough, dyspnea, cyanosis, and pulmonary edema. 

Differential diagnosis of ricin exposure shows early inhalational ricin poisoning and will have primarily respiratory signs and symptoms, whereas ingested ricin will probably present early with gastrointestinal symptoms. 

Balint (1974) and later Zhang et al. (1994) foimd that at the lethal dose in rabbits, ricin caused hemorrhage and necrosis. Christiansen et al. (1994) foimd that the release of norepinephrine from sympathetic nerves in the vasculature is not impaired by ricin. The CDC, under signs and symptoms of ricin poisoning that may be encountered, cite cardiovascular collapse (hypovolemic shock). 

Data on exposnre throngh ingestion are also limited. There are no reported cases of ingestion of pure ricin toxin. Nevertheless, the signs and symptoms of exposure to the pure toxin are probably similar to those following ingestion of masticated... 

Documented cases of human poisoning by ricin aerosol exposure are unknown. Cautious inferences may be drawn from observations of NHP exposed to ricin under controlled laboratory settings. Human toxicity from ricin inhalation would be expected to occur after a latency period of 24—72 h that may be characterized by loss of appetite and listlessness. Based on extrapolation from NHP studies, other signs and symptoms expected in humans after ricin inhalation may include listlessness, high fever, dyspnea, and coughing or bloody sputum that is delayed for 4—8 h after exposure, as well as bilateral abnormalities on chest radiographs, arterial hypoxemia, neutrophilic leukocytosis, and elevated protein levels in bronchial aspirates (Balint, 1974 Wilhelmsen and Pitt, 1996 Franz and Jaax, 1997). 

A 20 year old man allegedly attempted suicide by injection (s.c.) of an unknown amount of ricin from crude castor seed extract (Targosz et al., 2002). The victim entered the hospital about 36 h after injecting the toxin with symptoms of nausea, dizziness, weakness, chest and abdominal pain, and myalgia with paraesthesia of the extremities. Signs included hypotension, anuria, metabolic acidosis, and a bleeding diathesis. Hepatorenal and cardiorespiratory failure preceded death from an asystolic arrest approximately 54 h after injection. 

Ricin acts rapidly and irreversibly, which makes treatment very difficult after signs and symptoms appear. Symptomatic care is the only intervention presently available to clinicians treating aerosol ricin poisoning. 

In one large clinical trial,40 low doses (18-20 pg/ m2) of intravenous ricin administered to cancer patients were well tolerated. Flulike symptoms with fatigue—in some cases very pronounced fatigue— and muscular pain were common, and sometimes nausea and vomiting occurred. The symptoms began 4 to 6 hours after administration and lasted for 1 to 2 days. Two toxic deaths were reported in Phase I clinical trails of the closely related protein toxin, abrin these patients had general seizures and other signs of central nervous system toxicity. 

What Are the Signs and Symptoms of Ricin Expo.sure ... 

Showing these signs and symptoms does not necessarily mean that a person has been exposed to ricin. 

Activated charcoal lavage may be helpful immediately after ingestion of castor beans or ricin, but ricin acts rapidly and irreversibly, which makes treatment very difficult after signs and symptoms appear. Symptomatic care is the only intervention presently available to clinicians treating aerosol ricin poisoning. Additional information on ricin may be found in Franz and Jaax (1997). 

There are no specific data on injection of ricin into humans, and likely human symptoms are based on those of animal models. Initially it would be expected that a person would experience local pain and necrosis at the site of injection, followed by systemic signs. Death would likely ensue at 3 or more days after exposure. 

---