Pathogenesis and action of toxins
The disease is the most frequent and typical variant of bacterial food poisoning. The pathogenesis is based on the effects of Bacillus cereus enterotoxins. If the dose of toxins entering the body is high, they may penetrate the systemic circulation. In this case, they exert a superantigen effect, leading to severe shock-like reactions.
The clinical presentation directly depends on the properties of the predominant toxin:
- Thermostable enterotoxins cause the clinical picture of gastritis to predominate.
- Thermolabile enterotoxins lead to the predominance of enteritis symptoms.
A specific sign of such poisoning is a sharp decrease in blood pressure (down to 80–60 mmHg), which is completely disproportionate to the severity of dyspeptic disorders (nausea, diarrhea).
Clinical presentation and leading syndrome
The disease always begins acutely and suddenly against a background of complete health. The main symptom complex includes nausea, recurrent vomiting, and abdominal pain, localized predominantly in the epigastrium and umbilical region.
The stool is loose, abundant, and watery. Initially, it still retains a fecal character, but as the infection progresses, it loses it. Admixtures of mucous lumps and fragments of undigested food may appear in the stool.
Important rule: in bacterial food poisoning, the severity of the patient's condition is always determined by the degree of dehydration, and the clinical signs of dehydration prevail over the intoxication syndrome. Intoxication itself is mild, and body temperature may be normal or rise only to subfebrile and occasionally febrile values. The severity of dehydration directly correlates with the frequency of vomiting and defecation and can reach grade III.
Classification by severity
The clinical course of poisoning is divided into three variants depending on the degree of fluid loss and symptom severity:
- Mild course: intoxication is practically absent or very mild. Temperature remains within normal or subfebrile limits. Vomiting is either absent or occurs once. Stool is increased up to 1–3 times a day. Dehydration does not exceed grade I.
- Moderate course: the patient is troubled by recurrent vomiting, stool becomes abundant and increases up to 10 times a day. Hemodynamic disorders appear (tachycardia, unstable and lowered blood pressure). Febrile fever is sometimes recorded. Grade II dehydration develops.
- Severe course: a rare variant, entirely due to critical dehydration. Signs of intoxication and high fever are atypical. Coming to the fore are agonizing vomiting, stool up to 20 times or more per day, headache, dizziness, tachycardia, and a drop in blood pressure down to fainting states. Convulsions, oliguria, and decompensated dehydration develop, which leads to shock if untreated.
Risk groups and complications
The prognosis for Bacillus cereus food poisoning is generally favorable, and the duration of the disease is only 2–3 days. However, there is a risk group that includes elderly and senile individuals with a burdened premorbid background.
Complications are extremely rare but pose a serious life threat. These include hypovolemic shock and acute cardiovascular failure.
Diagnostics
The diagnosis is established based on a combination of clinical, epidemiological, and laboratory data.
Clinical and epidemiological criteria:
- Acute, sudden onset and short incubation period.
- Group character of morbidity (outbreak among individuals who consumed the same foods).
- Dominance of gastritis or gastroenteritis with moderate intoxication.
Laboratory diagnostics are based on the bacteriological method. All patients admitted to the hospital undergo collection of gastric lavage fluid, vomit, and feces. The goal is to isolate opportunistic bacteria and rule out other truly pathogenic etiologies of the infection. During mass outbreaks, Rospotrebnadzor authorities additionally investigate suspected contaminated foods.
Toxin-clinic connection: ThermoStable — Gastritis (TSG), ThermoLabile — Enteritis (TLE).
Class and exam questions
Why might blood pressure drop sharply in Bacillus cereus poisoning?
Upon massive entry of enterotoxins into the bloodstream, they can act as superantigens. This provokes shock-like reactions with a specific disproportionate drop in blood pressure down to 80–60 mmHg.
Which syndrome is leading in this disease?
The leading syndrome is always dehydration. It is its degree that determines the severity of the patient's condition, while the general intoxication syndrome is mild.
What specimens are taken for bacteriological examination?
To confirm the diagnosis in a hospital setting, the patient's feces, vomit, and gastric lavage fluid are sent for analysis.
What else to study on this topic
- Mechanism of action of bacterial superantigens
- Differential diagnosis of gastritis and enteritis in food toxicoinfections
- Degrees of dehydration: clinical criteria of grade I, II, and III
- Rules for conducting an epidemiological investigation of food outbreaks
- Pathogenesis of hypovolemic shock development in dehydration
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