Corrosives/caustics

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