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CORROSIVES/CAUSTICS
CORROSIVES
They are substances that destroys the body tissues with which they come into contact .
They are:
ACIDS
ALKALIS
OTHERS
ACIDS
Inorganic/Mineral acids-sulphuric acid
HCl,HNO3 Organic-oxalic acid,acetic acid,formic
acid.
SULPHURIC ACID
SYNONYM:oil of vitriol,oleum
PROPERTIES: heavy,colourless,hygroscopic,non-fuming
USES:Batteries,industries,drain/toilet bowl cleaners,vitriolage
FATAL DOSE: 20-30 ml
TOXICOKINETICS: No absorption
MECHANISM OF ACTION
Acids
Release hydronium ions
Protoplasmic coagulation
Coagulation necrosis
SIGNS AND SYMPTOMS Burning sensation of GIT Intense thirst, Tongue-swollen,turns black/brown Teeth-chalky white Drooling vomiting Dribbling marks on face Stomach-perforation-peritonitis Strictures form pyloric obstruction,antral
stenosis
DIAGNOSIS
Litmus test:blue-pink Clothing stains+ few drops of sodium
bicarbonate,produces effervescence
MANAGEMENT
Decontamination of skin Respiratory distress Demulcents Emergency laparotomy Corticosteroids,antibiotics
THE DONT’S
No oral feeds No emetics or charcoal No gastic lavage Neutralisation with alkalis is dangerous
HYDROCHLORIC ACID
SYNONYMS:Muriatic acid,Spirit of salts PROPERTIES:colourless,fuming,turns
yellowish with air. USES:bleaching agent,dyeing
industry,metal refinery,preparation of Cl,metal/drain/ceramics cleaner.
MEDICINAL USES:achlorhydria,Hb estimation.
FATAL DOSE:30-40 ml TOXICOKINETICS:no absorption DIAGNOSIS:
1.litmus test
2.Stomach contents/vomitus
+
conc ammonia
White fumes of ammonium choride
MECHANISM OF ACTIONHCl
Hydronium ions
Protoplasmic coagulation(tissue proteins),forms coagulum.
Coagulation necrosis
Tisssue damage
SIGNS AND SYMPTOMS
Same as sulphuric acid poisoning It produces pronounced respiratory
distress Greyish discolouration Less chance of perforation It produces less severe effects since
HCl is naturally present in the body
MANAGEMENT
Same as for sulphuric acid poisoning Severe pain-morphine is given Eye injury-retraction of eye
lids+prolonged irrigation with normal saline or lactated ringers soln,15-30 min
Regular follow-up for strictures/stenosis,if present,dilatation or esophagogastrotomy done.
NITRIC ACID
SYNONYM:aqua fortis,red spirit of nitre. PHYSICAL PROPERTIES:colourless,yellow
fuming liquid,choking odour,dissolves all metals except Pt & Sb.
USES:engraving,electroplating,gold smith-aqua regia(HNO3:HCl::3:1),fetilisers
TOXICOKINETICS: absorption is negligible FATAL DOSE:20-30 ml
MECHANISM OF ACTIONReacts with protein & orgaic matter to produce trinitrophenol
Liberates nitogen monoxide,xanthoprotein is formed
It produces yellow discolouration of skin,coagulation of tissue proteins
Produces coagulation necrosis
SIGNS AND SYMPTOMS
Teeth-turns yellow Respiratory tract-
coughing,rhinorrhea,dyspnoea Abdomen-distention due to gas
formation,less perforation Oliguria with cast and antibodies
DIAGNOSIS
Litmus test Stomach contents+copper when heated
pungent,heavy,dark brown fumes
THERAPYSame as for sulphuric acid poisoning
The respiratory tract should be more secured.
ALKALIES
Examples include:
Ammonia-
Ammonium hydroxide-paint,oil,refrigerant
Ammonium bisulphate-fertiliser
Sodium hydroxide-drain/oven cleaner
Sodium carbonate-household cleaning agent,detergent
pot.hydroxide-drain cleaners,hearing aid batteries
PROPERTIES:
Ammonia:colourless,pungent,choking
Alkalis:white powder,colourless solns.
FATAL DOSE:
Ammonia:15-20 ml,pot.carbonate:15 gm
Sod/pot hydroxide:5 gm,
sod.carbonate:30 gm
TOXICOKINETICS: No absorption
Signs and symptoms
Skin-greyish,soapy,necrosed,cold,clammy
Oesophagus-dysphagia,vomiting,drooling,haematemesis
GI-corrosion produces red/brown appearance,greyish pseudomembrane forms,burning sensation,acrid,soapy and nauseous taste.
Mechanism of action
Hydroxide ions saponify FAs of the cell membrane
Protein disruption,solubilisation
Liquefaction necrosis,further penetration of alkali
MANAGEMENT
Decontamination of skin Respiratory system-endotracheal
intubation,cricothyrotomy,tracheostomy,oxygen inhalation.
Demulcents-milk,egg white,lemon,barley Assess fluid and electrolyte balance Unbearable pain/convulsion Corticosteroids-to prevent stricture formation Antibiotics-if perforation seen. Proton pump inhibitors
REFERENCES
Fundamental of forensic medicine and toxicology,2nd edition R.Basu,pg no.391-399
Textbook for medicine and toxicology,15th edition
V.V.Pillay,pg no.450-463Forensic medicine & toxicology,2nd edn
R.N.Karmakar,pg no.63-65