Etiology and classification of poisoning

Etiology and predisposing factors

The development of poisonings is closely linked to social, psychological, and domestic conditions. A number of key factors increase the risk of intoxication:

• Addictions: alcoholism, substance abuse, and various forms of chemical dependence.
• Psychoemotional stress: frequent stressful situations, dysfunctional family environments, as well as severe financial and domestic hardships.
• Severe living conditions: persistent tension provokes the development of mental disorders and creates a need for psychotropic medications. Under such conditions, people are more likely to turn to quacks and charlatans, as well as resort to illegal out-of-hospital abortions, which drastically increases the risk of severe toxic injuries.
• Domestic negligence: improper home storage of medications and aggressive chemical preparations. This factor is the absolute dominant cause of acute poisonings in childhood.

Classification by origin and routes of entry

For accurate diagnosis and selection of treatment tactics, intoxications are differentiated by several key criteria. Based on the cause and place of occurrence, accidental, intentional, suicidal, and criminal poisonings are distinguished. A separate group consists of medical errors and occupational intoxications.

Special attention is paid to domestic poisonings, which are most commonly associated with:

• attempts at self-medication;
• accidental or intentional drug overdose;
• severe alcohol and drug intoxications;
• carbon monoxide inhalation.

According to the route of toxin entry into the body, the following forms are distinguished:

1. Oral (per os) — swallowing of the poison, most typical for domestic settings.
2. Inhalation — breathing in toxic gases or vapors.
3. Percutaneous (per cutis) — penetration through the skin, including bites from venomous snakes, animals, and insects.
4. Injection — introduction of the toxin directly into tissues or the bloodstream.
5. Cavitary — entry of the toxic substance into the rectum, vagina, or external auditory canal.

Classification by course and severity

Depending on the rate of development of the pathological process and the frequency of toxin exposure, poisonings are divided into three types:

• Acute. Occur upon a single entry of poison into the body. Characterized by a sudden, acute onset and prominent specific clinical symptoms.
• Subacute. Like acute poisonings, they usually develop after a single exposure to a toxin, but the pathological process forms and manifests in a delayed manner.
• Chronic. Form as a result of prolonged or intermittent (regular) intake of poison in subtoxic (small) doses, which gradually exhaust compensatory mechanisms.

Depending on the severity of clinical manifestations, intoxications are traditionally subdivided into mild, moderate, severe, and extremely severe.

Main stages of poisoning

In the clinical course of acute poisonings, two consecutive stages are clearly traced, each having its own pathophysiological features.

1. Toxigenic stage This is the initial phase characterized by the direct action of the toxic substance on organs and tissues. During this period, specific clinical manifestations inherent to the particular poison predominate.

2. Somatogenic stage Occurs after the elimination, destruction, or deposition of the poison. Signs of activation of the body's adaptive reactions come to the forefront, aimed at restoring disrupted homeostasis. The key manifestations of this stage are:

• pronounced stress response;
• centralization of blood circulation (redistribution of blood to protect vital organs);
• reaction of the hemostatic system (changes in blood clotting).

Class and exam questions

What else to study on this topic

• Pathogenesis of the stress response in the somatogenic stage of poisoning
• Mechanisms of blood circulation centralization in acute intoxications
• Changes in the hemostatic system as an adaptive reaction to poison
• Specific symptoms of the toxigenic stage under various routes of poison entry
• Features of the development of chronic poisonings upon exposure to subtoxic doses

Other topics in «Chapter 18. Drug Addiction. Substance Abuse. Poisoning»

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.