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| Alkalies (Sodium hydroxide, Potassium Hydroxide, Ammonium hydroxide, Sodium carbonate, Potassium carbonate and Ammonium carbonate) |
Identification:
They are extensively used commercially. Most of these occur as white powders. Ammonia is a colowebsiteess gas with a very pungent, choking odour. Ammonium hydroxide is a liquid containing about 30 percent ammonia. Household bleaches commonly consist of 5 percent sodium hypochlorite solutions and cause mild irritation.
Route : Ingestion
Fatal dose : Sodium/Potassium hydroxide – 5g. Potassium carbonate – 18 g. Sodium carbonate - 30 g. Ammonia – 5 to 10 ml.
Fatal Period : usually within 24 hours
Mechanism of action : They are the commonest cause of chemical burns. The hydroxyl ion produces saponification of fat, soluble alkaline proteases, cellular dehydration and an exothermic reaction. They produce soft, gelatinous, friable eschars {liquefaction necrosis}. Ingestion of an alkali produces severe effects mainly on the lining of the oesophagus, while gastric involvement is less. Therefore stricture formation is much more common with alkalis than with acids.
Clinical picture : 1} There is a caustic taste and a sensation of burning heat extending from the throat to the stomach.
2} Vomited matters are alkaline and do not effervesce on contact with the ground. It is at first thick and slimy, but later contains dark altered blood and shreds of mucosa.
3} Purging is a frequent symptom, accompanied by severe pain and straining. The motion consists of mucus and blood.
4} Soapy feel and taste. Contact with skin causes greyish, soapy , necrotic area.
5} When strong alkali is ingested` abrasions, blisters and brownish discolouration are seen on the lips and skin about the mouth.
6} Oesophageal stricture formation is a major long-term complication.
7} Ammoniacal vapour when inhaled causes congestion and watering of the eyes, violent sneezing, coughing and choking. Sudden collapse and death may occur due to inflammation and much swelling of the glottis or later from pneumonia.
Treatment : 1} Demulcents, eg. White of egg, or milk, or water 1-2 glasses may be given if the patient is seen within 5-10 minutes of ingestion.
2} In mild cases the stomach can be washed carefully.
3} In poisoning by ammonia vapour, oxygen inhalation should be given or the patient should be kept in an atmosphere made moist with steam.
4} Keep the airway patent. Tracheostomy may be necessary.
5} Give adequate parenteral analgesics.
6} Steroids are useful in decreasing laryngeal inflammation
7} Antibiotics to prevent infection.
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