Corrosive poisons
•Have caustic or locally destructive effects on tissues (acids or alkali)
•Destroy tissues by direct chemical action (a function of pH and the capacity of the anion to combine with proteins).
•Acids also convert haemoglobin to a dark compound, hematin, which is then precipitated.
•They also cause a reflex loss of vascular tone.
•Acids often stain the area of contact black or brown and a few e.g. nitric acid (HNO3) produce yellow stains
Signs and symptoms - ingested poisons
•Severe burning pain in the mouth, pharynx, and abdomen, normally followed by vomiting and diarrhoea, containing dark precipitated blood.
•A Sharp fall in blood pressure.
•Asphyxia, which results from oedema of the epiglottis.
•If fever occurs later, it may indicate peritonitis or mediastinitis, which occurs as a result of perforation.
•Oesophageal necrosis with concentrated acids.
•In the long term, the patient may get an oesophageal stricture or pyloric stenosis due to scar formation particularly with alkali
Signs and symptoms - Inhaled corrosives (acute)
•Acidic fumes causes chocking and puking
•Headache and dizziness.
•Followed by a 6-8 hour latency period, after which, the victims develop pulmonary oedema with tightness in the chest, dryness, frothy sputum and cyanosis.
•Patients normally present with low blood pressure (BP), high pulse rates and noisy breathing on auscultation.
•Haemoptysis and shortness of breath may also occur and persist for several weeks.
Signs and symptoms - Inhaled corrosives (Chronic)
•Erosion of the teeth, followed by necrosis, chronic cough and frequent attacks of bronchopneumonia due to bronchial irritation.
Signs and symptoms - skin exposure
•Severe pain, yellow or brownish staining especially in white skinned individuals.
•A burn occurs and heals slowly with formation of scars.
•If the corrosive comes in contact with the eyes, conjuctival oedema and corneal destruction occur. These patients complain of pain and photophobia
Treatment - Ingested corrosives
•Try to dilute the acid or alkali using water or milk (10:1)
•Relieve the pain using morphine sulphate 5-10mg every four hours
•General measures
- Maintain adequate airway to manage asphyxia e.g. by intubation
- Treat shock (transfuse to restore BP if necessary)
- Give a steroid if there is a narrowing of the oesophagus e.g. prednisolone 2mg/kg/day.
- I.V parenteral nutrition in case of difficult food ingestion
NOTE:
•Do not induce vomiting, as this will cause further corrosion.
•Do not give acid or alkali, as this produces an exothermic reaction.
•Avoid the use of CNS depressants except an opioid like morphine for severe pain
Treatment - Inhaled corrosives
•Give steroids to reduce the progression of lung fibrosis.
•If the eyes are involved, dilute by flooding the affected eye with water from a shower or high fountain for not less than fifteen minutes (usually 20-30 minutes), with the eyelids open.
•Give systemic analgesics for the pain e.g. opioids
• Refer the patient to an ophthalmologist
Treatment - skin exposure
•Flood with water for not less than fifteen minutes
•Treat as a burn
Treatment - chronic exposure
•Stop the exposure to poison
•Manage pulmonary oedema with oxygen, diuretics and bronchodilators as well as steroids.
•If bacterial pneumonia occurs, administer organism specific antibiotics\
Prevention
•High water fountains and showers should be available in places of acid manufacture or any place where corrosives are handled.
•Persons dealing with corrosives should wear tight fitting goggles, rubber gloves and aprons.
•Storage places should be well ventilated before people are allowed to work in them.
•Gas masks should be won whenever necessary