Foodborne toxic infections

Mechanisms of toxic injury (using botulism as an example)

The action of bacterial toxins leads to systemic disorders. For example, the development of neuromuscular blockade is associated with the cessation of acetylcholine release in synapses, which clinically manifests as paralysis of various localizations, including the respiratory muscles.

The toxic effect on the autonomic nervous system is manifested by the suppression of the parasympathetic system. As a result, sympathetic tone dominates and hypercatecholemia develops, causing vascular spasm, pallor, blood pressure spikes, and dry mucous membranes. Due to intestinal paresis, anaerobic conditions are formed, contributing to additional production of botulinum toxin directly in the gastrointestinal lumen (autointoxication).

Systemic changes against the background of intoxication indicate profound hypoxia (tissue, hemic, circulatory). Macroscopically, organs are severely plethoric, with hemorrhages, and skeletal muscles acquire a specific "boiled" appearance. Important rule: there is a strict inverse relationship between the length of the incubation period and the severity of the paralytic syndrome.

Assessment of dehydration severity

The severity of cholera-like intestinal infections directly depends on the volume of lost fluid and electrolytes. There are four degrees of dehydration:

1. Grade I (loss of up to 3% of body weight): Moderate thirst, rare vomiting, pulse and blood pressure within normal limits. Diuresis is preserved.
2. Grade II (loss of 4–6%): Liquid stool up to 20 times, frequent vomiting. Cyanosis of the nasolabial triangle appears, the voice weakens. Short-term cramps in the calf muscles are possible. Tachycardia (up to 100 bpm), a 10–20% decrease in systolic blood pressure, and oliguria are noted.
3. Grade III (loss of 7–9%): Severe thirst, acrocyanosis, hoarseness of the voice. Cramps become prolonged and cover large muscle groups. Pulse is weak, up to 120 bpm, blood pressure drops to 50% of normal. Oligoanuria develops.
4. Grade IV (loss of >10%): General cyanosis, aphonia (complete absence of voice). Generalized tonic seizures lead to the formation of the "gladiator posture". Peripheral pulse is not palpable, blood pressure is critically low, and complete anuria occurs.

As dehydration progresses, hemoconcentration occurs (hematocrit rises above 55%), decompensated acidosis develops (pH drops below 7.30), and marked hypokalemia occurs.

Clinical syndromes and differential diagnosis

For rapid prescription of treatment, the diagnosis is often made based on clinical markers and epidemiological history before receiving bacteriological data.

• Cholera-like course: Characterized by a strict sequence (profuse diarrhea appears first, and only then is vomiting joined). There is no abdominal pain or fever. Signs of dehydration progress rapidly.
• Shigellosis colitis: Proceeds with high fever (often above 39°C), agonizing cramping pains in the lower abdomen, false urges, and tenesmus. The sigmoid colon is sharply spastic and painful. Stool is very frequent (more than 25 times), containing a lot of blood and mucus.
• Yersiniosis: Distinguished by polymorphism. Facial hyperemia, scleral injection, and "strawberry tongue" are typical. A scarlatiniform rash frequently occurs, concentrating around the joints, along with the "gloves and socks" sign. In 30% of cases, pseudoappendicular syndrome develops (inflammation is localized in the distal small intestine and cecum, rather than the appendix).
• Amebiasis: Distinguished by a gradual onset, low-grade fever, and right-sided colitis syndrome. A history of visiting endemic regions is often present. Can be complicated by an amebic liver abscess.

Briefly: answers to topical questions

Class and exam questions

What else to study on this topic

• Metabolic disorders: dynamics of hematocrit, pH, and blood electrolytes during fluid loss.
• Complications of intestinal infections: acute renal failure, infectious-toxic shock, cholera typhoids.
• Features of the management of comorbid patients (against the background of coronary artery disease and hypertension).
• Specific therapy: use of amebicides and antitoxic sera.

Other topics in the "Acute Intestinal Infections" section

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