Pediatric Mercury Poisoning

Introduction to mercury poisoning in children Mercury (Hg) is a silvery white liquid metal, commonly known as mercury, which has the property of evaporating at room temperature. Mercury and its compounds are toxic. Mercury poisoning can occur if the dosage is too high or the application time is too long. Metallic mercury is generally not used as a medicine. It is only used as a raw material for dental filling in dentistry, and it is mercury and other metals. The combined state of the material is used and will not be absorbed by the body. Common mercury compounds are mercury sulfide, mercuric chloride, mercurous chloride, oxidized mercury and organic mercury pesticides. There are many mercury-containing drugs, such as mercury, cinnabar, Dashengdan, Xiaoshengdan, mercury powder, and red mercury. Some Chinese medicines also contain mercury compounds, mostly mercury oxide. basic knowledge The proportion of illness: 0.005% - 0.006% Susceptible people: children Mode of infection: non-infectious Complications: acute peritonitis coma acute renal failure ataxia

Causes of mercury poisoning in children

(1) Causes of the disease

Metallic mercury vapor can be poisoned by inhalation in the respiratory tract. Generally, acute metal mercury poisoning is an industrial accident. Metallic mercury is absorbed by the digestive tract very little, and generally does not cause poisoning. There are many mercury-containing drugs. Inorganic mercury is internal, external and rectal. The drugs used in the body include mercury, ammonia, mercury, cinnabar, light powder, etc. Mercury poisoning can occur when the dosage is too large or the application time is too long. Among them, mercury is the most toxic, and most children are poisoned by eating this medicine. 0.1g can be fatal, organic mercury pesticides such as Sai Li San, Xi Li Sheng and other virulence, eating seeds with mercury-containing pesticides, eating fish in contaminated water, shellfish or drinking contaminated water can occur Poisoned.

(two) pathogenesis

Metallic mercury poisoning is mainly caused by inhalation of its vapor. Inorganic mercury and its compounds can inhibit the activity of many enzymes, causing central and autonomic nervous system dysfunction as well as kidney and digestive tract damage.

The large inhalation of metal mercury vapor is the main way to cause acute poisoning. After inhalation of mercury vapor, 75%-80% pass through the alveoli into the blood, distribute the whole body, and store the most mercury in the brain, kidney and lung. The storage time is longer. Mercury itself cannot pass through the blood-brain barrier and placenta, but after entering the blood, mercury is oxidized into divalent mercury ions, which combine with plasma proteins or sulfur-containing amino acids into brain tissue and placenta. Mercury has a special affinity for protein thiol groups. The combination of thiol groups inhibits the activity of a series of thiol-containing enzymes, causing metabolic disorders in the body, especially the functions of the central nervous system and autonomic nerves.

Mercury compounds can be rapidly absorbed through the digestive tract and skin mucosa. The absorption rate in the digestive tract is related to its solubility in water and gastric juice. After absorption, it mainly binds to plasma proteins in the blood, and a small part binds to hemoglobin. Organs with the highest kidney content, 80% of the mercury accumulates in the proximal convoluted tubules of the kidney, causing swelling and necrosis of renal tubular epithelial cells. Mercury ions and enzymes combine to lose enzyme activity, affect cell function, and cause central and autonomic nerves. System dysfunction and kidney, digestive tract damage.

Oral mercury (mainly mercury chloride) poisoning amount is 0.1g, adult lethal dose is 0.3-0.5g, child lethal dose is 0.1g, oxidized mercury lethal dose is 1~1.5g, calomel (main component is The lethal dose of mercurous chloride is 2 to 3 g.

Prevention of mercury poisoning in children

1. Mercury-related work must be carried out in a closed operation, ventilation in the workplace, exhaust equipment, use of mercury and its preparations should be avoided on the ground.

2. The mercury-containing pesticide should be stored in a closed state, and the mixed seeds should be preserved to prevent children from eating.

3. To prevent excessive use of drugs containing mercury, children should avoid using mercury-containing drugs.

4. Do a good job in personal protection, and mercury contacts should have regular physical examinations.

5. Prevent pregnant women, nursing mothers, and children from eating aquatic animals contaminated with mercury.

6. Prevent children from feeding or touching paints, toys, furniture, etc. containing mercury.

Complications of mercury poisoning in children Complications acute peritonitis coma acute renal failure ataxia

In severe cases, diffuse peritonitis can be caused by gastrointestinal perforation; severe acidosis, myocardial damage, heart failure, shock and acute renal failure can occur in severe cases; acral necrosis, coma, convulsions, etc. can occur, and hydrocephaly mainly causes ataxia , hemiplegia, mental retardation, slow growth, etc.

Symptoms of mercury poisoning in children Common symptoms Abdominal pain with nausea, vomiting, irritability, gastrointestinal symptoms, kidney damage, convulsions, diarrhea, gums, swelling, urgency, heavy breathing, heart failure

Acute poisoning

The symptoms of oral acute poisoning are:

(1) Digestive tract symptoms: tight throat and pain, abdominal pain, nausea, vomiting, diarrhea, etc., metal taste in the mouth, oral mucosa may have congestion, edema and necrosis, gums can be swollen, hemorrhage and ulceration, tongue, sublingual gland And the ear gland is swollen, the sick child has blood mucus in the mouth, the vomit has gray mucus and bloody mucosal debris, the stool has mucus and blood, and contains a lot of exfoliated intestinal mucosa, feelings of urgency and urgency, similar to dysentery feces, some patients from the stomach Intestinal perforation forms peritonitis.

(2) Kidney disease: urinary or nouria, proteinuria, hematuria, tubular urine, etc., with facial edema, often appear 4 to 10 days after poisoning, there is still azotemia, hyperkalemia Acute acid failure such as acidosis is life-threatening.

(3) Others: The sick child's pulse is weak and irregular, breathing difficulties, etc., severe cases can cause severe acidosis, myocardial damage, heart failure, shock, coma, convulsions.

2. Chronic mercury poisoning is rare in children, but mink disease and limb pain are syndromes of chronic mercury poisoning.

(1) Limb pain: manifestations of irritability, apathy, photophobia, sweating, high blood pressure, decreased muscle tone, neuritis, stomatitis, salivation, gastritis and hair loss, as well as various rashes and secondary skin infections, The tip of the toe and the nose are initially pink, the crotch and the tip of the nose are often scarlet, and the hand and foot are dark red with plaque-like ischemic and congested areas, palm and ankle peeling, itchy skin and severe pain in the hands and feet. Even refers to the toe nail shedding, the occurrence of extremity necrosis, common tachycardia and myocardial damage, the beginning of sputum reflexes normal or hyperthyroidism, disappeared later, occasionally fever, peripheral leukocytosis, proteinuria and diabetes.

(2) Minamata disease: Methylmercury poisoning caused by shellfish caused by ingestion of fish contaminated by mercury, was first discovered in Minamata Bay, Japan, hence the name.

1 main performance: for sensory disturbances, pain, numbness, difficulty in chewing and swallowing, speechlessness, deafness, visual impairment, photophobia, weakness, ataxia, hemiplegia, tremor, abnormal personality, mental retardation, confusion, convulsions, etc. .

2 Infant mink disease: pregnant women eat this kind of fish, when shellfish suffer from mercury poisoning, methylmercury can enter the child through the placenta or breast milk, causing baby poisoning. The child born can also develop water rickets, and the sick child will appear soon after birth. Different levels of sputum and mental retardation, the hair, blood, urine methyl mercury components are elevated, light growth is slow, its hair, blood, urine methyl mercury component is high, urine such as mercury containing 0.02mg / L, generally can prove the disease.

Examination of mercury poisoning in children

Blood can be measured, the amount of mercury in the urine, blood mercury, urinary mercury is significantly increased, but not as a basis for poisoning, there are regional and individual differences, only indicating the absorption of mercury, but also sodium dimercaptopropane or dimercapto Disodium is used for mercury flooding test.

1. Urine examination General routine examination has proteinuria, tubular urine, hematuria, oliguria or no urine, special examination for urinary mercury is significantly elevated, urine mercury check normal value:

(1) Dithizone thermal nitration method: <0.05 mg/L (2.5 mol/L).

(2) Protein precipitation method: <0.01 mg/L (0.5 ol/L).

(3) Atomic energy absorption method: <0.02 mg/L (1.0 mol/L).

2. Blood examination is generally routine examination, often accompanied by an increase in the total number of white blood cells in the peripheral blood, left shift of the nucleus, liver function damage, kidney damage, kidney damage, hyperkalemia, acidosis, etc.

Blood mercury examination was significantly elevated, with a normal value <2 mg/L.

According to the clinical selection of X-ray chest X-ray, B-ultrasound, electrocardiogram, brain CT and other examinations, abnormal electrocardiogram, such as arrhythmia.

Diagnosis and identification of mercury poisoning in children

According to the medical history, clinical manifestations and laboratory tests, urinary mercury, blood mercury is significantly elevated and other results can be diagnosed.

Differential diagnosis

1. Identification of dysentery with mucus and blood, and a large amount of exfoliated intestinal mucosa, the feeling of urgency and heavy, similar to dysentery feces, should be noted.

2. Identification of myocarditis with myocardial damage should be differentiated from myocarditis.

3. With encephalitis, encephalopathy identified with symptoms of nervous system damage and encephalitis, encephalopathy.

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