Iodine poisoning: signs, consequences, what to do

Although a bottle of iodine alcohol solution, a powerful antiseptic, is in every home medicine cabinet, probably not everyone knows that iodine poisoning is possible, and its excess can even lead to thyroiditis.

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Causes iodine poisoning

To synthesize thyroid hormones, which are responsible for regulating the body's metabolism and energy homeostasis, ensure normal brain development, the functioning of the immune system and other important functions, a person needs iodine. And in case of problems with the thyroid gland, endocrinologists prescribe iodine-containing drugs to patients.

The International Council for the Control of Iodine Deficiency Disorders (ICCIDD) recommends a daily intake of about 0.15 mg for adults. At the same time, for different age groups, both the optimal physiological amount of iodine per day (the first number) and the maximum permissible amount (that is, the amount that can be consumed without negative consequences) have been determined: children aged 1-3 years - 0.09/0.2 mg; 4-8 years - 0.1/0.3 mg; 9-13 years - 0.12/0.6 mg; adolescents and young people 14-18 years - 0.13/0.9 mg; adults - 0.15/1.1 mg.

Exceeding the maximum permissible levels of iodine can lead to poisoning. It is also necessary to take into account the different individual susceptibility to this microelement, which may be lower than the recommended amounts.

The generally accepted causes of iodine toxicity leading to poisoning are related to:

• with transdermal absorption with external use of an alcohol solution of iodine or iodophor preparations on large areas of skin or with constant and repeated local application;
• with oral intake of iodine-containing preparations, this consumption may be accidental or in some cases deliberate to cause harm to oneself;
• with inhalation of iodine vapors. Most often, iodine vapor poisoning threatens people involved in the production of acetic acid, halogen lamps, automobile glass, and certain types of polymeric materials that use iodine and its salts.

It should be borne in mind that diagnostic studies, in particular, CT coronary angiography or coronary angiography with contrast, are carried out using contrast agents containing radioisotopes of iodine (sodium iodide 123 or 131). Despite all the advantages of interventional diagnostic methods, X-ray examinations with radioactive iodine are a fairly common source of excessive, almost toxic effects of iodine. According to the annually published international reference book Side Effects of Drugs, a single intravenous dose of a contrast agent can contain up to 13.5 mg of free and, on average, 35-45 g of bound iodine. Because of this, some patients may experience thyroid dysfunction for one to one and a half months, and in some cases either subclinical hyperthyroidism or (after several months) overt hypothyroidism develops.

Is it possible to be poisoned by blue iodine? Blue iodine is a dietary supplement based on heat-treated starch (indicated in the instructions as its polysaccharides amylose and amylopectin) with the addition of iodine tincture. That is, it is an iodine-dextrin compound that is formed during the typical staining of amylose of potato or corn starch with iodine. Poisoning with it is unlikely, although in the presence of problems with the thyroid gland or an overdose, the toxic effect of the iodine included in this dietary supplement cannot be ruled out.

Risk factors

Are there risk factors for iodine poisoning? Doctors note that even if a person does not take medications or dietary supplements containing iodine, the presence of a history of: increases sensitivity to this chemical element, and therefore increases the risk of iodine toxicity and poisoning.

• hyperfunction of the thyroid gland (with the development of thyrotoxicosis);
• any inflammatory processes in the thyroid gland - thyroiditis, primarily of autoimmune etiology (Hashimoto's thyroiditis);
• diffuse toxic goiter;
• thyroidectomy (partial or complete removal of the thyroid gland).

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Pathogenesis

The toxicity of iodine, which is a halogen and a reactive non-metal, is due to its strong oxidizing properties, and the pathogenesis of poisoning lies in its ability to react with most simple substances, as well as to denature (coagulate) protein molecules, including protein enzymes.

Iodine penetrates through the skin and mucous membranes (even intact ones), so iodine poisoning through the skin is quite possible. Although the level of its bioavailability when applied locally (to the skin) has not been fully studied, according to the results of several foreign studies, its bioavailability - taking into account evaporation - is 6.5-8%. And if before applying iodine (50 mg) to a skin area, the average serum iodide level was 0.024 mg / l, then after two hours it could increase to 0.27 mg / l and remain at this level for 24 hours. That is, the fact of systemic absorption of iodine when applied externally is practically proven: it enters the blood, and then into the tissues of various organs (including the thyroid gland), and in cases of immoderate use it can cause systemic effects.

When corrosive exposure to high concentrations of iodine taken internally, severe irritation and burning of the mucous membranes of the pharynx, larynx and esophagus occurs, acute edema of the basal membrane of the serous membrane of the stomach with ulcerative damage to its mucous epithelium. Iodine affects various organs, which leads to the appearance of certain symptoms.

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Symptoms iodine poisoning

The most characteristic symptoms that can appear in the rather rarely observed iodine poisoning through the skin - when using a regular 5% aqueous-alcoholic solution of iodine (iodine tincture) or iodinol) - doctors call iodism.

It manifests itself in the form of: a metallic taste in the mouth, lacrimation (increased secretion of tears, lacrimation) and salivation (excessive salivation); rhinitis, sore throat and severe cough; dizziness and severe headache. The skin - where the iodine was applied - turns red, swells and becomes covered with a rash like hives or purple acne.

All of the above can also be observed in cases of toxic effects of iodine when inhaling its vapors or a long-term overdose of iodine-containing drugs. In addition, the following are possible: swelling of the lips, tongue, face, limbs; swelling of the lymph nodes; a feeling of heat in the chest area; fever; weakness and heaviness in the legs.

The obvious first symptom of accidentally or intentionally drinking an alcoholic iodine solution is coloring inside the oral cavity and a strong burning sensation that quickly spreads to the pharynx, esophagus and stomach cavity (with the development of pain). Swelling of the pharynx, larynx and lungs, asphyxia, vomiting (if there are starchy substances in the stomach, the vomit may be blue) and bloody diarrhea are also noted.

As a result of dehydration and disruption of homeostasis, blood pressure drops sharply, heart rate increases; then arrhythmia develops, the pulse weakens, cyanosis of the skin is observed, the person loses consciousness and falls into shock or coma.

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Complications and consequences

Considering the participation of iodine in the synthesis of thyroid hormones, which regulate many biochemical processes in the body, the consequences and complications of iodine poisoning affect:

• thyroid function and the production of thyroid-stimulating hormones, first temporarily reducing it (Wolf-Chaikoff effect) and then increasing it again. In this case, some patients may develop iodine-induced hypothyroidism - in a subclinical or overt form;
• digestive system and gastrointestinal tract - with serious damage to the mucous membranes and the occurrence of acute esophagitis, gastroenteritis, esophageal stricture;
• kidney function - with the appearance of protein in the urine (proteinuria) or a complete absence of urine (anuria).

Increased iodine intake, which is essentially latent poisoning, has been shown in European and Chinese studies to increase the incidence of autoimmune thyroiditis and the number of registered cases of papillary thyroid cancer.

Diagnostics iodine poisoning

In iodine poisoning, diagnosis is based on clinical history, a combination of symptoms, and the results of blood and urine tests for iodine content.

In case of certain symptomatic features, the levels of thyroid hormones in the blood are determined - T3 (triiodothyronine) and T4 (thyroxine), and the titers of thyroid antibodies are also determined.

Differential diagnosis

In doubtful cases, differential diagnostics are necessary, especially when the causes of the body's reaction to toxic effects are associated with the oral administration of iodine-containing drugs.

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Treatment iodine poisoning

Acute iodine poisoning usually requires calling emergency medical care or urgent treatment at a medical facility. At home, you should give milk to drink, not very thick flour "mash" (a tablespoon of wheat flour per glass of water), liquid starch (cooled), 3% soda solution, and to avoid iodine absorption - an aqueous suspension of activated carbon. In this case, vomiting should not be induced.

It is clear that at home there is no such medicine, or rather a means for neutralizing halogens and cyanides, as sodium thiosulfate; it is used by doctors - orally (5% solution) or by inhalation.

Further drug treatment is carried out in the intensive care unit, if necessary - with provision of respiratory function (artificial ventilation). And all the drugs used, administered intravenously (infusion), are aimed at removing iodine from the body and stabilizing the condition of the tissues of the liver, kidneys, myocardium and brain.

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Prevention

How can you prevent iodine poisoning? First, keep medications away from children.

Never take iodine-containing drugs and dietary supplements at your own discretion and in high dosages. This especially applies to children and the elderly.

In production facilities where chemically unsafe iodine-containing substances are used, the iodine content in the air should not be higher than 1 mg/m3. There should be personal protective equipment, and technical safety regulations that must be followed.

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Forecast

The amount of iodine, the route of its entry into the body and the intensity of symptoms determine the prognosis of the outcome of poisoning. With timely assistance, the person recovers.

But severe iodine toxicity can lead to death. The average lethal dose for an adult is 30 mg/kg, which is about 2-3 g for a body weight of 70-80 kg.

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