ANTISEPTICS
Antiseptics are chemicals that are applied to living tissues to kill
bacteria or inhibit their growth. Free iodine (I2) has significant
concentration-dependent tissue and systemic toxicity. Iodide (I-) causes a
negative anion gap and is associated with thyroid disorders, salivary
gland disorders, and dermal reactions. Most acute exposures to boric acid
are benign. Severe toxicity results from chronic exposure or massive
exposure. Characteristic symptoms of boric acid toxicity include greenblue vomit and diarrhea, erythroderma with desquamation, and central
nervous system (CNS), renal, bone marrow, and hepatic injury.
Iodophors, Iodine, and Iodide
Iodophors such as povidone-iodine (Betadine) are complex detergentbased solutions of iodide (I-), free iodine (I2), and iodine bound to
povidone, a carrier molecule that limits the availability of free iodine.
The toxicity of iodine is much greater than that of iodide. Most iodophors
contain only 80 to 120 μg/100 mL of free iodine, making them much less
toxic than older iodine preparations such as tincture of iodine, which
contains 2 g of iodine in 100 mL. Nevertheless, severe toxicity after
exposures to iodophors have been reported. The iodophors are used as
antiseptics and irrigants. Iodine-containing solutions are also used as
expectorants, as vaginal irrigants, for contrast studies in radiology, and as
therapy for acute hyperthyroidism. Lugol’s iodine solution, commonly
used in the acute treatment of hyperthyroidism, contains 5 % I2 and 10 %
potassium iodide (I-).
Pathophysiology
The antibacterial property of iodide is facilitated by a covalent linkage
to bacterial cell surface glycoproteins, which enhances the bactericidal
properties of polymorphonucleocytes. The mechanism of iodine toxicity
in human poisoning is not well defined. Based on the significant lactic
acidosis seen in acute iodine toxicity, the cellular toxicity has been
attributed to interference with cellular oxidative metabolism and
adenosine triphosphate production. Chronic exposure results in
disturbances of thyroid structure and function and may be manifest as
hyperthyroidism, hypothyroidism, goiter, or thyroiditis.[ These seemingly
paradoxical responses are due to the stimulation of increased thyroid
hormone production in some individuals and the blockade of thyroid
hormone production in others. The developing fetus is especially
susceptible to the thyroid suppressant effects of iodine.
Iodine toxicity occurs through ingestion, through absorption during
wound irrigation with iodophor-containing solutions, through mucosal
exposure, and during topical application to dermal burns.
Clinical Presentation of Exposure to Antiseptics, Disinfectants, and
Sterilizing Agents:
•Respiratory irritation, distress, or failure
•Dermal and mucous membrane irritation and burns: Acute ingestion of
iodine (I2)-containing solutions results in gastrointestinal irritation,
gastrointestinal ulceration,
•Lethargy, coma, seizures
•Metabolic acidosis
•Embolic phenomena (hydrogen peroxide)
• Erythroderma (boric acid), ioderma (iodides)
•Hyperchloremia, negative anion gap (iodides)
•Chronic ingestion of iodine leads to thyroid disorders in some
individuals. Large or chronic exposure to iodides results in sensitivity
reactions manifest as painful salivary gland enlargement and a variety of
dermal eruptions, so-called ioderma.
Treatment
•Stabilize patient and provide supportive care
•gastric decontamination may be done by aspiration with a small
nasogastric tube. Iodine may be converted to less toxic iodide by the
administration of starch or milk. Sodium thiosulfate will also convert
iodine to iodide.
•Activated charcoal is indicated unless significant symptoms suggest the
need for endoscopic evaluation of caustic injury
•Decontaminate skin and mucous membranes with water (all) or
polyethylene glycol—industrial methylated spirits (phenol)
•Treat dermal or mucous membrane burns
•Institute fluid management
•Perform endoscopy and surgical intervention for gastrointestinal burns
•Enhance elimination
• Hemodialysis: formaldehyde, boric acid, iodine (severe poisoning)
•Hyperbaric oxygen therapy: emboli with hydrogen
peroxideSymptomatic
•patients with chronic exposure to iodine-containing medications require
evaluation of thyroid function.