CBRNE - Staphylococcal Enterotoxin B Clinical Presentation
- Author: Bruce A Gleason, MD; Chief Editor: Duane C Caneva, MD, MSc more...
Historical clues are important in diagnosing enterotoxin-induced gastroenteritis.
After either gastrointestinal or inhalational exposure, a nonspecific flu-like illness may develop, with symptoms to include myalgias, headache, chills, and fever.
GI symptoms start within several hours of ingestion of contaminated foods, beginning with significant nausea, vomiting, and intestinal cramping, followed by urgency and profuse watery nonbloody diarrhea. Symptoms normally resolve within 12-24 hours. Multiple family members or patrons of the same eating establishment may be affected.
Ingestion of staphylococcal enterotoxin B (SEB) that is produced and excreted by S aureus in improperly refrigerated, stored, and handled foodstuffs results in food poisoning.
The incubation period is 3-12 hours (rarely up to 18 h) after ingestion.
Classic symptoms are an abrupt onset of intense nausea, vomiting, cramping abdominal pain, and diarrhea, which incapacitate the patient.
Most cases are self-limited and resolve in 8-24 hours.
Inhalation of staphylococcal enterotoxin B (SEB) does not occur in the natural setting and should be considered a result of an intentional event.[1, 10]
After respiratory exposure to aerosolized SEB, the clinician would most likely be presented with numerous patients of all ages within a short period of time (most likely within 1-6 h of an exposure) who were exposed at a common location and developed respiratory difficulty. Because of the difficulties in obtaining large quantities of the toxin and difficulty in efficient dispersion as an open-air aerosol, this location most likely would be an enclosed space, such as a gymnasium, arena, or office building.
Symptom onset after inhaling SEB may vary from 3-12 hours. Sudden onset of headache, fever, myalgia, nonproductive cough, chills, shortness of breath, and retrosternal pain can be caused by SEB at low doses via inhalation.
Respiratory symptoms may include dyspnea, nonproductive cough, and retrosternal chest pain. Disease may progress with increasing respiratory distress, hypoxia, and ultimately respiratory failure depending on the degree of systemic inflammation and resulting pulmonary edema.
Fevers can range from 103º-106ºF and may last up to 5 days.
The cough may last up to 4 weeks.
Vital signs should be followed closely in order to monitor for signs of multiorgan failure.
Inhalational exposure to higher levels of SEB may lead to septic shock and death.
Animal experiments in mice have shown that SEB can lead to symptoms after intranasal and conjunctival exposure. Ocular exposure is associated with conjunctivitis and periorbital edema. These two exposure routes can also lead to systemic activation of the immune system. The clinical significance in humans is unknown.[10, 11]
Physical examination in staphylococcal enterotoxin B (SEB) intoxication may be unremarkable, but, most likely, the patient presents with complaints of acute onset and either appears in significant abdominal pain or acutely short of breath. Symptoms are of abrupt onset.[3, 9]
If the route of entry of the toxin is GI, patients may appear dehydrated, depending on the severity of nausea and vomiting, and often complain of acute abdominal cramping and diarrhea.
Physical examination may reveal hypotension, tachycardia, hyperperistalsis, and diffuse nonlocalizing abdominal pain. Any stool or diarrhea is hemoglobin negative, barring other pathology.
In inhalation of aerosolized SEB, patients are acutely and significantly short of breath and complain of severe substernal chest pain. On examination, however, usually reveals clear lung fields with no evidence of consolidation or effusion. Other than a reflexive tachycardia, which is likely to be seen, cardiac examination is normal.
With significant inhalational exposure, the patient may display pulmonary edema or signs and symptoms consistent with acute respiratory distress syndrome (ARDS).
Most patients also have a fever up to 103o -106o F if significant pulmonary involvement has occurred.
After toxin is produced in improperly refrigerated, stored, and handled foodstuffs, ingestion of staphylococcal enterotoxin B (SEB) causes food poisoning. Inhalational exposure would most likely be related to a terrorist or biologic warfare event. Case reports have been documented of intranasal exposure secondary to nasal packing after surgical procedures as S aureus does colonize the nasal passages.
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