Lead poisoning is intoxication caused by the ingestion of this element into the body by oral or inhalation. Signs of the acute form are gastrointestinal syndrome, general and focal neurological symptoms, toxic phenomena, impaired consciousness. Chronic varieties lead to a decrease in appetite, malaise, a weakening of intelligence, a change in the psycho-emotional state. Pathology is diagnosed on the basis of the clinical picture, anamnesis, a test for the presence of coproporphyrin and lead in urine, the results of a radioisotope study of the composition of bone tissue. Treatment – gastric lavage, antidotes, infusion and post-syndrome therapy.
ICD 10
T56.0 Toxic effect of lead and its compounds
General information
Lead poisoning (saturnism) is the most common type of heavy metal poisoning. About 500 thousand deaths caused by Pb intoxication are registered annually in the world. Children are affected 4-5 times more than adults. When inhaled, 10 times more of the toxic substance is absorbed than when it is swallowed. The maximum number of cases is detected among the population of countries with a low level of social and economic development. This is due to the widespread use of household items and finishing materials, in the manufacture of which a cheaper soft metal is used compared to analogues.
Causes
The most common cause of lead intoxication in children is attempts to melt the substance on a gas stove. Similar actions in the open air rarely result in poisoning, but in an enclosed space, the concentration of vapors quickly reaches critical values. The maximum permissible content of the toxicant is 0.3 micrograms/m3. Other risk factors:
- Dishes with lead. Soft metal is used to make glaze, which is used to cover clay vessels. It is the main element of the solder that holds together parts of buckets, barrels and other containers not intended for food. Cooking and storing food in such items for several months becomes the cause of Saturnism.
- Leaded gasoline. To improve performance, some fuels are mixed with lead tetraethyl. When such gasoline is burned, Pb is released into the environment. Since 2000, fuel with similar additives has been banned in all countries of the world with the exception of Yemen, Afghanistan, Palestine and North Korea.
- Finishing materials. The danger is represented by paints made with the use of a meerkat. Lead poisoning occurs during the burning of painted materials with insufficient ventilation. It is usually combined with signs of moderate damage by carbon monoxide and other gorenje products.
- Ingestion of metal. It is diagnosed in children and patients suffering from allotriophagy. Develops when a person eats small pieces of a toxicant or objects containing it. The course of the disease is usually chronic, acute varieties of pathology are rarely detected.
- Production. Employees of enterprises using Pb are one of the most vulnerable groups of the population to poisoning. In case of violation of safety regulations, saturnism is diagnosed in 95% of people who are in the immediate vicinity of the source of infection on the territory of production workshops.
Pathogenesis
The lethal single dose of lead is 0.5 grams, chronic processes occur with a daily intake of 0.0005 g / day. Penetrating into the body, the substance is fixed on the surface of red blood cells and spreads through the tissues of the central nervous system, kidneys, liver. About 90% of the metal is deposited inside the bones. The direct toxic effect is due to the formation of bonds between lead ions and the centers responsible for the formation of certain enzymes. The production of hexokinase, glucose-6-phosphate dehydrogenase is blocked, the cycle of tricarboxylic acids is disrupted.
Protein formation in the liver, myocardium and vascular wall is reduced. There is an inhibition of the synthesis of porphobilinogen, which leads to an increase in the concentration of free porphyrin, the appearance of coproporphyrin in the urine. The victim develops anemia caused by a violation of the process of mitotic division of maturing blood cells. There is a deficiency of vitamins, which contributes to disorders of the activity of all body systems.
Classification
Lead poisoning is classified by severity (mild, moderate, severe, lethal); by stages (I – functional disorders. II – structural and organic changes); according to the method of receipt of the poison (oral, inhalation, percutaneous, mixed). In practice, systematization along the course of the disease is considered the most significant. The following forms are distinguished:
- Acute. Occurs with simultaneous admission of 0.1-0.5 g. Symptoms develop after 1-5 hours. The clinical picture is pronounced, the condition of the victim deteriorates sharply. Emergency hospitalization is required to provide specialized medical care. Acute poisoning occurs mainly in employees of enterprises after accidents at work.
- Subacute. It is detected in young and middle-aged children after casting figures from molten metal. When preparing it, they inhale a sufficient amount of toxic fumes to defeat. Signs of the disease begin to be determined after 5-24 hours, clinical manifestations are moderate. Transportation to a medical institution is shown.
- Chronic. It is formed after several months or years of regular use of microscopic doses of metal. The picture of Saturnism manifests itself gradually, starting with insignificant and almost always unnoticed phenomena. A complete symptom complex is detected after 3-5 years. Emergency hospitalization is not indicated, treatment is carried out on an outpatient basis.
- Long-term consequences. It is impossible to completely remove lead from the body, so its toxic effect persists throughout the patient’s life. Long-term consequences are determined after 10-30 years or more in the form of neurological disorders, arrhythmia, progressive decline in intelligence, kidney failure.
Symptoms
The initial sign of an acute form of the disease is considered to be severe soreness near the navel. The victim has symptoms of dyspepsia, bloating, constipation (sometimes diarrhea). The picture resembles a functional disorder of the intestine. Then there are phenomena that suggest the defeat of the central nervous system: rigidity of the neck muscles, confusion, unbearable headache, convulsions, behavioral disorders. In severe cases, coma, non-canceling vascular collapse, cardiac arrest are detected.
The symptom complex in chronic intoxication in children is relatively poor. Decreased appetite, constipation, vomiting, headaches, mental retardation are determined. Against the background of a decrease in the number of red blood cells and the formation of anemia, the skin and mucous membranes become pale. The child is weakened, sluggish, inactive. Obvious hemodynamic disorders are usually absent. Signs may be blurred, fuzzy, and it is not always possible to determine the cause of their appearance in a timely manner.
In adults, lead poisoning manifests itself in the form of several syndromes. One of the first symptoms is frequent cephalgia of a blunt nature. Later, dizziness, weakness, decreased ability to work, sleep disorders are added. Possible deterioration of vision, hearing, taste sensations. Objectively, there is increased sweating, red dermographism, tremor, decreased muscle tone. Palpation — moderate soreness of muscles, areas of projection of nerve trunks. Severe exotoxicosis is accompanied by paresis, vascular crises, encephalopathy.
Gastrointestinal disorders are characterized by spilled cramping pains (lead colic), constipation, bloating. The content of gastric hydrochloric acid increases, which provokes heartburn. The stool takes the form of sheep feces. A purple-gray border forms along the edge of the gums, especially pronounced in patients suffering from caries. With liver damage, complaints of heaviness on the right under the ribs, the appearance of vascular asterisks on the skin are registered. The full picture does not develop in all episodes. The victim may have 2-3 of the following symptoms.
Complications
The main complication in moderate poisoning is the formation of mental defects, especially pronounced in children. Lagging behind peers is diagnosed in 55-60% of patients with chronic form and in 45-50% of patients with acute intoxication. The second most common consequence of lead use is neurological disorders. They are detected in 30% of victims, may occur several years or decades after the initial symptoms are relieved.
Lead poisoning of the maximum degree is sometimes accompanied by liver failure. This leads to the accumulation of toxic metabolites, an increase in enzyme activity, and the development of hyperbilirubinemia. It occurs in 3-5% of cases, can cause the death of the victim. Kidney failure develops less frequently. On the part of the musculoskeletal system, spontaneous bone fractures, muscle atrophy due to a violation of the nervous innervation of the extremities and deterioration of protein synthesis are detected.
Diagnostics
In case of chronic exotoxicosis, the diagnosis is made by a primary care physician: a therapist, a general practitioner. Confirmation is made on the basis of specific laboratory tests, visualization of bone tissue. An ambulance doctor can also assume the presence of saturnism, but such diagnoses are not usually used in the practice of ambulance. To differentiate with anemia and encephalopathy of other origin, tumors, vascular malformation, parasitosis, consultation of a hematologist, infectious disease specialist, neurologist is necessary. Survey methods:
- Physical. There are a number of signs of damage to the central nervous system, gastrointestinal tract, peripheral nerves and bones. On examination, pallor, decreased muscle tone, asterisks on the skin, a border on the gums are noted. The patient is irritable, short-tempered. HELL can persist or transform in any direction. The pulse is more than 90 beats /minute. The liver extends beyond the costal arch.
- Laboratory. Urine coproporphyrin is 100 mcg/g or more, the concentration of delta-aminolevulinic acid is above 15 mcg/g. Blood lead content >60 mcg%. Hemoglobin, color index and red blood cells are reduced. Serum iron >32 mmol/l or is kept within the normal range. There may be a deficiency of total protein.
- Instrumental. The basis of the hardware examination is radiography of large bones, where signs of toxicant deposition are detected. ECG shows a decrease in the height of the P wave, a decrease in the R-R interval, a violation of intracardiac conduction. Ultrasound shows an increase in the size of the liver, spleen, structural changes in the renal parenchyma.
Treatment
The treatment of lead poisoning is carried out by a toxicologist, and in his absence, a therapist. Severe processes require the participation of a resuscitator. Hospitalization is carried out in a specialized toxicological center or a multidisciplinary clinic that has an ICU in its composition. Planned therapy of chronic processes of the first degree is carried out on an outpatient basis. In addition to the attending physician, the patient should be observed by a psychiatrist, a neurologist.
First aid
At the stage of first aid in acute form, regardless of the path of penetration of the poison, a probe cleansing of the stomach is shown. As a washing liquid, 2% sodium bicarbonate or protein suspension is used. After the end of the manipulation, a non—absorbable enterosorbent is injected – activated carbon. The antidote to heavy metal salts is unithiol. The drug forms low-toxic complexes with the substance, which are removed by the kidneys. The dosage is 1 ml of 5% solution per 10 kg of the victim’s weight, the method of administration is injectable, intramuscular.
Symptomatic treatment is required. With the development of seizures, anticonvulsants are used, infusion therapy is prescribed to eliminate hypovolemia. The volume of fluid is calculated in such a way as to compensate for losses, but avoid hyperhydration (10-20 ml / kg of body weight). Crystalloid compositions are used, and in case of hemodynamic disorders – colloidal compositions. According to the indications, inotropic and respiratory support is carried out. The chronic type of poisoning does not require urgent care.
Hospital treatment
The main method of drug therapy in a hospital setting is a combination of unithiol with calcium tetacin. Tetacin accelerates the excretion of lead from biological fluids in urine by 20-50 times, and unithiol binds the toxic substance and makes it harmless to the kidneys. The course of treatment is 2-5 days, then an equal break is required. The total number of courses is no more than three. The use of tetacin without unithiol is contraindicated, since it increases the symptoms of poisoning and creates a risk of renal insufficiency.
To correct the impaired functions of the body, the victim receives multivitamins, iron preparations, hepatoprotectors. The development of encephalopathy with cerebral edema requires the use of diuretics. Surgical decompression techniques are not used. The elimination of Pb in chronic poisoning is carried out according to the same scheme as in acute. Infusions are not prescribed for outpatient work with a patient. Compliance with a diet with a reduced amount of fat, fluid restriction, increased iron and calcium content in food is shown.
Experimental techniques
South Korea is conducting research aimed at developing new ways of detoxification. Fluorescent receptors combined with magnetically active particles are introduced into the patient’s bloodstream. The substance binds to heavy metal ions. After that, the patient is hemodialysis, affecting the blood with a magnet. In the laboratory, the method allows you to remove 96% of the toxic substance, but it has not yet received wide practical distribution.
Rehabilitation
After relief of acute symptoms and removal of the bulk of the harmful substance from the body, the patient needs long-term rehabilitation. The supervision of a psychiatrist, neurologist is required. In 35-40% of cases, sedatives and antidepressants are prescribed to the patient. Therapy aimed at improving brain function (nootropics) is shown. In case of neurological disorders, means are used to improve the conduction of the pulse. It is recommended to stay in sanatorium-resort institutions, physical therapy.
Prognosis and prevention
Severe acute lead poisoning has an unfavorable prognosis. The mortality rate is 25% even with timely administration of antidotes. Neurological and mental disorders persist for life in 15-40% of patients after treatment: epileptimorphic seizures, lethargy, in children — physical and mental retardation. Chronic processes always lead to damage to the central nervous system. Patients become aggressive, hot-tempered, they show a significant weakening of mental abilities.
Prevention of lead poisoning consists in the use of gloves, masks and gas masks when working with substances containing lead (paints, whitewash). It is necessary to abandon the use of dishes on which there are traces of soldering or glaze treatment. With frequent contacts with the toxicant, it is necessary to correct the diet so that it contains an increased amount of calcium, vitamin C, zinc. It is recommended to use garlic, seaweed, aloe vera juice. It is important to monitor the behavior of children and explain to them what dangers arise during the melting of soft metal.