Iodine poisoning: signs, consequences, what to do

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

[1], [2], [3]

Causes of the iodine poisoning

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

The International Council for the Control of Iodine Deficiency Disorders (ICCIDD) recommended its daily consumption by adults about 0.15 mg. At the same time, for different age groups, both the optimal physiological amount of iodine per day (the first figure) and the maximum allowable (that is, which can be consumed without negative consequences) are defined: children aged 1-3 years old - 0.09 / 0.2 mg; 4-8 years - 0.1 / 0.3 mg; 9-13 years old - 0.12 / 0.6 mg; adolescents and young people aged 14–18 –0.13 / 0.9 mg; adults - 0.15 / 1.1 mg.

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

The generally recognized causes of toxic effects of iodine, leading to poisoning, are related:

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

It should be borne in mind that with the use of contrast agents containing iodine radioisotopes (sodium iodide 123 or 131), diagnostic studies are carried out, in particular, CT coronography or coronary angiography with contrast. With all the advantages of interventional diagnostic methods, X-ray examinations with radioactive iodine are a fairly common source of excessive, practically toxic effects of iodine. According to the annual published international directory 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, in some patients, dysfunction of the thyroid gland can be observed within one to one and a half months, and in some cases, either subclinical hyperthyroidism develops, or (after a few months) open  hypothyroidism.

Could there be blue iodine poisoning? Blue iodine is a dietary supplement based on thermally treated starch (indicated in the instructions as its amylose and amylopectin polysaccharides) with the addition of iodine tincture. That is, it is an iodine-dextrin compound, which is formed by typical iodine staining of amylose of potato or corn starch. Poisoning is unlikely, although in the presence of problems with the thyroid gland or overdose, the toxic effects of iodine in this dietary supplement cannot be ruled out.

Risk factors

Are there any  risk factors for  iodine poisoning? Doctors say that even if a person does not take drugs or dietary supplements containing iodine, increase sensitivity to this chemical element, and, therefore, increase the risk of toxic effects of iodine and poisoning presence in history:

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

[4],

Pathogenesis

The toxicity of iodine, which belongs to halogens and is 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 and also to denature (coagulate) protein molecules, including protein enzymes.

Iodine penetrates the skin and mucous membranes (even intact), so it is quite possible poisoning with iodine through the skin. Although the level of its bioavailability when applied locally (on the skin), is not 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 the skin site, the average serum iodide index was 0.024 mg / l, after two hours it could increase to 0.27 mg / l and stay at that level throughout the day. 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 excessive use may cause systemic effects.

When corrosive exposure to high concentrations of iodine, taken orally, severe irritation and burns of the mucous membranes of the pharynx, larynx and esophagus, acute edema of the basement membrane of the serous membrane of the stomach with ulcerative damage to its mucous epithelium. Iodine acts on various organs, which leads to the appearance of certain symptoms.

[5], [6], [7],

Symptoms of the iodine poisoning

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

It manifests itself in the form of: metal taste in the mouth, lacrimation (increased discharge of tear fluid, tearing) and salivation (excessive salivation); rhinitis, sore throat and strong cough; dizziness and severe headache. The skin where iodine is applied is red, swollen and covered with a rash such as urticaria or purple acne.

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

The obvious first symptom of an accidentally or deliberately drunk alcohol solution of iodine is staining inside the oral cavity and a strong burning sensation that quickly spreads to the pharynx, esophagus and stomach cavity (with the development of pain). Also marked swelling of the pharynx, larynx and lungs, asphyxia, vomiting (in the presence of starchy substances in the stomach, vomit masses may be blue) and bloody diarrhea.

Due to dehydration and disturbance of homeostasis, blood pressure drops sharply, the frequency of heart contractions increases; then arrhythmia develops, the pulse weakens, skin cyanosis is observed, the person loses consciousness and falls into a shock or coma.

[8]

Complications and consequences

Given the participation of iodine in the synthesis of thyroid hormones that 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 (Wolff-Chaykoff effect), and then increasing again. At the same time, some patients may develop iodine-induced hypothyroidism in 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 the complete absence of urine (anuria).

Increased iodine intake, which, in fact, is a latent poisoning, according to European and Chinese studies, increases the prevalence of autoimmune thyroiditis and the number of reported cases of papillary thyroid cancer.

Diagnostics of the iodine poisoning

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

With certain symptoms, they determine the levels of thyroid hormones in the blood - T3 (triiodothyronine) and T4 (thyroxin), and also determine the titers of thyroid antibodies.

Differential diagnosis

In doubtful cases, differential diagnosis is necessary, especially when the reasons for the body's reaction to toxic effects are associated with oral iodine-containing preparations.

[9], [10], [11], [12], [13]

Treatment of the iodine poisoning

Acute iodine poisoning usually requires calling for emergency medical care or urgent treatment in a hospital. At home it is necessary to give milk to drink, not very thick flour "mash" (a glass of water - a tablespoon of wheat flour), liquid brewed starch (cooled), 3% soda solution, and to avoid absorption of iodine - water suspension of activated charcoal. In this case, vomiting can not be called.

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

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

[14]

Prevention

How can I prevent iodine poisoning? First, keep the medicine away from children.

Never take iodine-containing drugs and dietary supplements at their discretion and in high dosage. This is especially true of children and the elderly.

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

[15]

Forecast

The amount of iodine, the way it enters the body and the intensity of symptoms determine the prognosis of the outcome of poisoning. With timely help, the person recovers.

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

[16], [17], [18]