Diagnosis of poisoning
Last reviewed: 23.04.2024
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The first stage of the diagnosis of poisoning is an assessment of the general condition of the patient. Severe poisoning may require emergency measures to treat acute cardiovascular failure (collapse).
The fact of poisoning can be known on admission. In patients with difficult-to-explain symptoms, especially with changes in consciousness, poisoning should be suspected. Targeted self-poisoning in adults involves the possibility of using several poisonous substances. Anamnesis sometimes plays a major role. Since many patients can not give reliable information (small children, patients with impaired consciousness, adults after a suicide attempt or with psychoses), it is necessary to interview friends, relatives and emergency or rescue personnel. Even patients who seem to be credible may not accurately describe the time taken and the amount of poison taken. If possible, you should examine the patient's housing in search of evidence (half-empty packs of drugs, signs of abuse). The patient's medical record and prescriptions can be useful. If the possibility of poisoning at work is not ruled out, colleagues and management should be interviewed. All chemical plants should have detailed data on toxicity and specific treatment directly at the workplace.
In the US, Europe and some countries in Asia and South America, information on industrial and household chemicals can be found in the poison control centers. Consultations with the staff of the Center are very useful, as the information printed on the package about the composition of the chemical, first aid and antidotes can be outdated and inaccurate. In addition, the contents of the container may be substituted, or the packaging may be damaged. Centers for controlling poisoning will help in the identification of unknown tablets in appearance, they also have the opportunity to provide advice to a toxicologist. The telephone number of the nearest center can be found along with the numbers of other emergency services on the first page of the local telephone directory, or through the telecom operator, or in the US - by dialing 1-800-222-1222.
In a clinical examination, you can identify the symptoms that are characteristic of poisoning with a specific poison (a specific odor, injection lanes with intravenous medication, signs of chronic alcoholism).
It should be borne in mind that even in case of poisoning, mental disorders can be caused by other causes (infectious lesions of the central nervous system, TBI, hypoglycemia, stroke, hepatic encephalopathy, Wernicke's encephalopathy). When poisoning with drugs in older children, adolescents and adults, it is necessary to remember the possibility of a suicidal attempt. After stabilizing the condition, they need a psychiatrist consultation.
[Laboratory diagnosis of poisoning
In most cases, laboratory tests are not very informative. The standard available tests for frequently abused drugs give only a qualitative rather than a quantitative assessment. These tests can give false results and determine a limited number of substances. In addition, the presence in the patient's blood or urine of such a drug does not necessarily mean that it was he who triggered the clinical manifestations of poisoning.
The concentration of most substances in the blood is not easy to determine, and this indicator does not always affect the tactics of treatment. When poisoning with certain drugs (for example, paracetamol, acetylsalicylic acid, CO, digoxin, ethylene glycol, iron, lithium, methanol, phenobarbital, theophylline) concentration in the blood helps to choose treatment. Many experts recommend measuring the concentration of paracetamol in the blood of all patients with mixed poisoning, since paracetamol poisoning in the early stages is often asymptomatic, can cause serious long-term effects that can be prevented by the administration of an antidote. For some substances, other blood tests (for example, PTI / INR with an overdose of warfarin, the determination of the content of methemoglobin in the blood for some poisonings) can help in the choice of treatment. In patients with impaired consciousness or vital functions (cardiac, pulmonary, etc.), as well as poisoning with certain poisons, it is necessary to determine plasma electrolytes, creatinine, glucose, nitrogen content in blood, osmolarity, arterial blood gas composition. With specific poisoning, other laboratory tests can be shown.
For certain poisonings (for example, iron, lead, arsenic, other metals, or if a packet with cocaine or another drug swallowed by the carrier is "swallowed"), an abdominal radiograph can help localize the swallowed. Radiography is also indicated for patients with serious signs indicating the possibility of poisoning with an unknown poison.
When poisoning with drugs that affect the cardiovascular system, or with unknown drugs, it is necessary to conduct ECG and cardiomonitoring.
If the concentration of the substance rises after its initial decrease, or the symptoms of poisoning persist unusually long, it is necessary to assume the presence of bezoars, either long-acting poisoning or repeated exposure (repeated abuse).