What Is Cadmium Poisoning?

Cadmium poisoning is mainly caused by inhalation of cadmium smoke or dust of cadmium compounds. A large amount of inhalation can cause acute pneumonia and pulmonary edema; chronic poisoning causes pulmonary fibrosis and kidney disease. Industries that come into contact with cadmium include smelting, spraying, welding, and casting bearing surfaces of cadmium, cadmium rods in nuclear reactors or graphite rods covered with cadmium as neutron absorbers, cadmium batteries and other cadmium compound manufacturing. Japan reported "painful disease" is a chronic cadmium poisoning caused by long-term ingestion of water sources contaminated with cadmium sulfate.

Basic Information

English name

cadmium poisoning

Visiting department

Internal medicine

Multiple groups

Cadmium industry practitioners

Common causes

Inhalation of cadmium fume or cadmium compound dust; smoking, etc.

Common symptoms

Nausea, vomiting, abdominal pain, diarrhea, general weakness, muscle aches, cough, chest tightness, dyspnea, chills, etc.

Causes of cadmium poisoning

Cadmium fumes and dust can be inhaled through the respiratory tract. Cadmium absorption in the lung accounts for 25% to 40% of the total entry. If you smoke 20 cigarettes a day, you can inhale 2 to 4 micrograms of cadmium. The absorption rate of cadmium through the digestive tract is related to the type of cadmium compounds, the amount of cadmium and whether they are co-intake of other metals. For example, when the intake of calcium and iron is low, the absorption of cadmium can be significantly increased, while the intake of zinc can be suppressed. Cadmium absorbed into the blood mainly binds to red blood cells. The liver and kidney are the two major organs that store cadmium in the body, and the cadmium contained in the two accounts for about 60% of the total cadmium in the body.

Clinical manifestations of cadmium poisoning

1. Ingestion of acute cadmium poisoning

It is mostly caused by ingestion of acidic food in cadmium containers. After several minutes to hours, symptoms appear, similar to acute gastroenteritis: nausea, vomiting, abdominal pain, diarrhea, general weakness, muscle soreness, and headache, muscle pain, Dehydration can occur due to dehydration, or even acute renal failure and death. The lethal dose of oral cadmium salts in adults is more than 300 mg.

2. Acute inhalation of cadmium poisoning

Caused by inhalation of high concentrations of cadmium smoke, the upper respiratory tract mucous membrane irritation symptoms first, these symptoms are relieved after disengagement. After an incubation period of 4 to 10 hours, coughing, chest tightness, dyspnea, chills, sore muscles of the back and limbs, and joint pains were observed. The chest X-ray showed flaky shadows and thickened lung texture. Severe patients develop delayed pulmonary edema, which can die from respiratory and circulatory failure. A few patients have liver and kidney damage. A few cases of pulmonary fibrosis occur after the acute phase, leading to pulmonary ventilation dysfunction.

3. Chronic cadmium poisoning

Long-term excessive exposure to cadmium mainly causes kidney damage, and very few patients with severe advanced disease may have skeletal lesions. Inhalation poisoning can still cause lung damage.

(1) Renal damage Early renal damage is manifested as proximal renal tubular reabsorption dysfunction, low molecular proteins (2 microglobulin, vitamin A binding protein, lysozyme, ribonuclease, etc.) appear in the urine, and glucosuria can also occur , High amino acid urine and high phosphate urine. Subsequently, high molecular weight proteins (such as albumin, transferrin, etc.) can also be excreted due to glomerular damage. The renal structure of advanced patients is damaged and chronic renal failure occurs. Renal dysfunction will persist even after disengagement. The incidence of kidney stones is increased among workers exposed to cadmium for a long time.

(2) Lung damage is chronic progressive obstructive emphysema, pulmonary fibrosis, and eventually pulmonary hypofunction. Obvious pulmonary dysfunction usually occurs after the appearance of urinary protein.

(3) Bone damage and painful disease Bone damage can occur in patients with severe chronic cadmium poisoning in the late stage, manifested as systemic bone pain, with varying degrees of osteoporosis, osteomalacia, spontaneous fractures, and severe renal tubular dysfunction syndrome. Multiple patients have multiple pathological fractures. Urine tests have low-molecular-weight proteinuria, increased calcium and urinary phosphate. Increased blood cadmium and decreased blood calcium. The occurrence of painful pain is still related to nutritional factors (low protein, low calcium and low iron) and multiple pregnancy factors.

(4) Others Patients with chronic poisoning are often accompanied by macular degeneration of the neck and teeth, loss or loss of smell, nasal mucosa ulcers and atrophy, mild anemia, occasional anorexia, nausea, mild abnormal liver function, weight loss, and hypertension. Long-term exposure to cadmium workers increases the incidence of lung cancer.

Cadmium poisoning test

Urine cadmium

The normal value of urinary cadmium is mostly below 1 g / g creatinine (or 1 g / L), and the upper limit is mostly 5 g / g creatinine (or 5 g / L). Urinary cadmium can reflect recent cadmium exposure and to some extent reflect cadmium load in the body, especially cadmium levels in the kidney .

Blood cadmium

Blood cadmium fluctuates greatly and can be used as an indicator of recent exposure. After stopping contact, it descends quickly. The World Health Organization recommends an individual blood cadmium cutoff of 5 g / L. In chronic cadmium poisoning, urine 2MG often exceeds 420 g / g creatinine (420 g / L), and even exceeds 1000 g / g creatinine (1000 g / L).

3. Other

Urinary 6-keto-PGF1, NAG, IAP, THG, and GAG excretion increased.

Diagnosis of cadmium poisoning

Acute cadmium poisoning

Diagnosis is not difficult based on contact history, respiratory symptoms, and gastrointestinal manifestations.

2. Chronic cadmium poisoning

In addition to professional history and clinical symptoms, a diagnosis is made based on chest radiographs, lung function, renal tubular function, and urinary cadmium.

3. For the diagnostic criteria of occupational cadmium poisoning, refer to the national standard GBZl7-2002.

Differential diagnosis of cadmium poisoning

Ingestion of acute poisoning should be distinguished from food poisoning and acute gastroenteritis; acute inhalation of poisoning should be distinguished from upper respiratory infections and cardiogenic pulmonary edema. Chronic cadmium poisoning needs to be distinguished from renal dysfunction caused by other heavy metals or drugs.

Cd poisoning treatment

Acute cadmium poisoning

(1) First-aid treatment Oral poisoning as soon as possible with warm water for gastric lavage, catharsis, and rehydration to correct water and electrolyte disorders; acute inhalation poisoning should be evacuated from the scene as soon as possible, keep quiet, rest in bed, inhale oxygen, and keep the airway open 10% silicone aerosol inhalation to eliminate foam. Adrenal corticosteroids can reduce capillary permeability, and it should be used in an early quantitative manner.

(2) Cadmium expulsion treatment: Disodium edetate can be given, and an appropriate amount of 2% procaine is injected intramuscularly. The drug is contraindicated in patients with significant renal impairment and can be switched to sodium dimercaptosuccinate, orally or by injection.

(3) Symptomatic treatment In the case of acute ingestion of cadmium poisoning, symptomatic treatment is mainly used. A large amount of fluid is given, atropine is injected to prevent vomiting and eliminate abdominal pain, and antibiotics are given to prevent secondary infection. Severe patients can be treated with hemodialysis and cadmium expulsion.

2. Chronic cadmium poisoning

Generally speaking, cadmium expulsion treatment is not recommended, because the cadmium combined with the complexing agent increases the kidney cadmium accumulation and aggravates renal toxicity. Mainly symptomatic treatment. Ethyl dithiocarbamate has caused clinical concern in the treatment of chronic cadmium poisoning.

Prevention of cadmium poisoning

1. Smelting and use of cadmium and its compounds should have good ventilation and closed devices. In addition to the necessary exhaust equipment for welding and electroplating, personal gas masks should be worn during operation. Do not eat or smoke at the production site. The maximum allowable concentration of cadmium oxide in production sites specified in China is 0.1 mg / m ³ .

2. Cadmium-plated utensils cannot store food, especially acidic food such as vinegar.

3. Cadmium contaminates the soil, which can cause public ailments. The pollution of cadmium to the soil mainly comes through two forms. One is that the cadmium in industrial waste gas diffuses with the wind and is naturally deposited in the soil around the factory. Contaminated by cadmium. In order to prevent the pollution of cadmium to the environment, environmental protection work must be done well and the environmental hygiene standards of cadmium must be strictly implemented.