LECTURE ON CORROSIVES

Doctor Amina RaoDepartment Forensic Medicine And Toxicology

CorrosivesCorrosion means dissolution or

gradual wearing away by chemical action.

Classification Of Corrosives Mineral Acids

Sulphuric Acid, Nitric Acid ,Hydrochloric AcidOrganic Acids

Carbolic Acid , Acetic Acid , Salicylic Acid , Oxalic Acid

Vegetable Acids

Hydrocyanic AcidAlkalis Caustic potash and Soda , Ammonium Hydroxide

Mineral Acids and Caustic Alkalis These are called corrosive poisons. In dilute solutions they act as irritants.Mechanism Of Action Their action is mainly a local one on the

tissues of the alimentary tract and to some extent on the respiratory tract.

As a rule, there is no remote Systemic Action with the exception of shock.

There action is characterized by : Extraction of water from the tissues. Coagulation of cellular proteins. Conversion of hemoglobin into Haematin.

General sign and Symptoms

1) Immediately , soon after swallowing the poison following can happened :

2) BURNING SENSATION in the mouth , throat , esophagus , stomach and abdomen followed by INTENSE THIRST , DYSPHAGIA, and VOMITING of shreddy blood stained material.

3) VOMIT may b acidic or alkaline in reaction depending upon the substance taken.

4) Signs of corrosion of mouth , lips or both.5) The tongue is shriveled according to the nature of

the corroding agent.

4) With the ingestion of a. Corrosive acidsThe bowels tend to be constipated and urine

scanty.b. With AlkaliesThere may be tenesmus and frequency of

stool with blood and mucus.5) Traces of poison may also find their way

into Trachea followed by Respiratory Symptoms e.g Dyspnoea is often present from oedema of glottis and is more marked in the volatile or strong fuming fluids.

General sign and Symptoms(CONT…)

SULPHURIC ACID ( MINERAL ACID ) Corrosive irritant if diluted. Colourless,odourless.non fuming,

hygroscopic and produces coagulation necrosis of the tissues in contact.

Perforation of stomach is commonest in poisoning due to sulphuric acid.

Signs and Symptoms : Burning pain , Thirst , Black Vomit ,detachment of

corroded mucous membrane , dysphagia , chalky white teeth. Black trickle marks on lips , cheeks and chin , abdominal pain , collapse , coma and death. Fatal Dose : 10 – 15 mlFatal period : 12 hours

Medicolegal importance Accidental Vitrolage Abortificent Succidal

Vitrolage Throwing of any corrosive on a person with

malicious intent. These fluids are usually thrown on the face with

the object of destroying vision or causing facial disfigurement and this result in Grievous hurt.

E.g Sulphuric Acid ( OIL OF VITRIOL)is most commonly employed for this purpose and hence it is called vitriolage.

Vitriolage

1) Nitric Acid and carbolic acid are fewer times used.

2) The use of caustic soda , caustic potash , iodine and marking NUT juice has also been recorded.

3) Sulphuric acid produces severe chemical burns.

They are characterized by discolouration and staining of stan and clothing ( colour changes).

Brown or black in case of Sulphuric acid . Yellow in case of Nitric acid.4) In H2SO4 vitriolage Trickle marks, Appearance of vesication And real line of

demarcation and presence of chemical substance in the stains

noticed.

Treatment of Vitriolage Wash away corrosive acid with large

amount of water and soap or dilute solution of NaHCO3 or KHCO3.

Later a thick paste of magnesium oxides applied.

skin raw surfaces can be covered by Antibiotic ointment.

EYE Involved:Treatment with large amount of water

followed by irrigation 1 % solution of sodium bicarbonate .

Few drops of olive oil instilled into eyes. Steroids and Antibiotic containing eye

drops are very helpful.

TREATMENT FOR H2SO4 POISONING Stomach wash with soft rubber tube

(Levine tube ) Give milk + egg white + melted butter. Magnesium oxide ( thick paste apply on

skin ) 10 mg Morphine IM ( injection ) for pain. IV fluids Oxygen / Cortisone. Oesophageal stictures in sulphuric acid

poisoning can be prevented by giving steroids.

Hydrochloric Acid (HCL)Physical and Chemical Properties:Colourless,volatile,odourless liquid has a burning sour taste.Sources: Industries,Commercial,Laboratories e.g. A normal digestive fluid

of stomach.Action Locally : Corrosive, Inflammation

of respiratory tract due to inhalation of fumes.

Indirectly : Shock due to severe pain.Fatal Dose : 15 – 20 ml concentrated.Fatal Period : 18 – 36 hours or more.

Features :1) Burning pain in mouth ,throat, esophagus

and stomach, spreading over the abdomen.2) Erosion : 1) Of Skin Appearance : usually no erosion after a few

days. 2) Of Mucous Membrane Of Mouth

and Tongue: Similar as in case of skin.3) Difficulty in Speech and Swallowing.4) Teeth Damage 5) Eructation is present.

6) Thirst Present.7) Vomiting and Vomitus Reaction : Strongly

present.8) Altered blood : Present9) Tenesmus : May be Present 10)Tenderness over Abdomen : Present11)Stiffness of Abdomen : May be due to

distension of stomach.12)Perforation or rupture of Stomach : uncommon13)Urination : Suppressed.14)Nature of Stool : Mucus with altered blood may

be present.15)Cause of Death : Shock,Laryngeal

spasm,pulmonary oedewr due to tickling of acid or vomitus or inhalation of vapour of the acid.

POSTMORTEM APPEARANCES1) Here there may not be much corrosion

of the skin. There my be damage of the skin over these areas with brownish parchmentisation.The mucous membranes of the mouth and tongue show reddish brown corrosion. Similar changes may be seen on the inner surface of esophagus.

2) The stomach is soft, swollen with congestion desquamation,haemorrhagic points and ulceration of the inner surface. It contains altered blood with mucous shreds.

POSTMORTEM APPEARANCES(CONT…)

3) Perforation is uncommon.

4) The upper part of the small intestine shows signs of Irritation.

5) In case if vapours are inhaled, there occurs congestion of the respiratory tract with the congestion and oedema of the lungs. Similarly if vomits is inhaled same findings appear.

MATERIALS TO BE PRESERVED FROM DEAD In all these cases,

I. Stomach with contents.II. A loop of upper part of small intestine.III. Half of the liver.IV. Half of each kidney in 1 container.V. Corroded areas of skin in other container.VI. Acid stained clothes are preserved

separately.Preservatives Viscera and skin are preserved in

absolute alcohol or rectified spirit , clothes are sent without any preservation.

MECHANISM OF ACTION : (AFTER CORROSIVE CONTACT TO SKIN )Inflammatory reaction first : 4 – 7 days

Granulation Stage : Fibroplasias and formation of collagen starts.

2nd and 3rd Week : Tissues become weak.Third Stage (Cicatrisation Stage) : Formation of

scar tissue which increases the chances of perforation.

Their action is characterized by :I. Extraction of water from tissues.II. Coagulation of cellular proteinsIII. Conversion of hemoglobin into haematin.

DiagnosisRadiologyI. Acute Stage :1 – 10 days in peeding

perforations.II. Sub. Acute Stage : 11 – 16 days . Atony,dilation

and rigidity of the antrum and pylorus seen.III. Chronic Stage : Stenosis and contraction of the

antrum and pylorus occurs. Chest and abdominal X-rays and routine

Laboratory testing should be obtained to evaluate for Aspiration, perforation and organ dysfunction.

Endoscopy : performed for getting better results 12 – 24 hours e.g. to check perforation

Treatment 1. Weak acid : carbonated beverage or

citrus juice.2. Base Antacid.3. Do not perform gastric levag,it

increases the chances of perforation.4. Do not give any orally for 2-3 days

after water milk ,water electrolytes shafted be green.

5. Broad spectrum Antibiotics.6. For Esophageal stictures and gastric

outlets : obstruction may require subsequent dilatation or surgical reconstruction.

Treatment(CONT…)

6) Laprotomy is required for patients with gastric perforations and peritonitis.

7) Skin lesions need to be washed with soap and water followed by the application o some ointment.

8) Eye involvement needs irrigation with water or normal saline, also refer to ophthalmologist.

Medicolegal Aspects

i. Accidental Poisoning : Commonly found in many house hold agents e.g drain detergents, drain openers .

ii. Accidental Ingestion : The intestine accidently warms the unintentional taken of his mistake causing him to spit of the acid which dribbles out on his chin and some stains on his clothes. Further more attempts to wipe the burning stuff from the lips may result in spreading it over the surrounding area and cheeks etc.

Medicolegal Aspects(CONT…)III. Succidal Poisoning : in intentional swallowing of the acid, intense pain may result in spluttering and staining of the mouth,chin, and clothing.

IV. Homicidal Poisoning : homocidal victims are usually incapable infants or intoxicated persons.

V. An acute exposure to the vapours in the industries may lead to death due to Respiratory distress.

VI. Prolonged exposure to the vapours of the agent in the industries may lead to Respiratory copmlications.

Medicolegal Aspects(CONT…)VII.In case of Fatal Poisoning Cases : By these acids , no trace of poisons may be discoverable in viscera. The quantity of free acid present ,specially important in HCL poisoning as this acid is contained uncombined with bases in the gastric juice to the extent of about 0.2% or more.

VIII.Sometimes disposal of the dead body may be affected by throwing the dead body into the acid with an attempt to dissolve the body of the victim as was practised by John George Haigh so called Acid Bath Murder.

Nitric acid (Mineral Acid) Aqua fortis Corrosive irritant if diluted. Nitric acid is a powerful oxidizing agent.Signs and Symptoms:Burning pain,thirst,yellow colouration of mucous membrane and teeth,yellow brown vomitus,tender and distended abdomen,oligurea,shock,choking,lacrimation, dyspnoea

and cough are due to INHALATION.Fatal Dose :15-20 mlFatal Period : 18 hours.

Xanthoproteic Reaction Xanthoproteic reaction occurs

with ingestion of nitric acid . Nitric Acid is a powerful oxidizing

agent and reacts with organic matter ( protein) to produce tri nitro phenol liberating nitrogen mono oxide is called Xanthoproteic Reaction.

Treatment o Stomach wash (with soft rubber tube)o Give milk – Magnesium oxide – Egg whiteo Melted Buttero 10 mg Morphine (pain relieft)o IV Fluids ( ice Sucking )o Cortisone (for treatment of shock and to

prevent oesophageal stictures)Medicolegal Points o Accidental o Succidal o Abortificiental / Vitriolage

Postmortem AppearancesThere may be signs of corrosion and partial

destruction of the parts with which the poison has been in contact.

Externally : The lips may be burnt and trickle marks may be found running from the mouth to the chin, neck,chest.

Internally : they vary in extent from localised patches to extensive AREAS particularly in stomach.

Stomach Perforation is common with sulphuric acid.

Irritation of Respiratory tract is found in case of volatile poisons e.g nitric acid,HCL.

Medicolegal AspectsAttempted succide with corrosives is not

seen now owing largely due to the use of other less painful substances like barbiturates and synthetic narcotics and organophosphate compounds.

Corrosives are rarely used for homocide owing to their painful action.Corrosives usually thrown on the face out of jealousy or in fits of rage ,

called vitriolage. They cause severe injury even death from accidental spilling.

Collapse from shock sets in witha. Cold clammy skin, sunken eyes, dilated pupil.b. Pale anxious facec. Rapid feeble pulse and sighing respirations.Consciousness is usually retained until near the end.Death : death may result from primary

shock, suffocation,due to oedema of glottis or perforation of stomach.

If quantity of poison swallowed is small, death may be delayed until Hypostatic pneumonia develops.

Patient may be recover and death may be later due to complications.

e.g Sticture of oesophagus with resulting emaciation and malnutrition.

The sites likely to be affected by local contact.

Treatment Stomach tubes and emetics are contraindicated.1) Soft stomach tube (Levine Tube) can be pass with

case within about an hour of ingestion of poison to prevent serious caustic burns of the stomach walll followed by ulceration,cautraction and stricture.

If an acid has been taken alkaline carbonates

are contraindicated because they liberate CO2

which may distend and rupture a damaged

stomach.2) Weak alkalis and plenty of water or neutralizing

agents such as milk and egg albumin should be given.

Treatment(CONT…)3) In case of Alkali : A weak acid such as vinegar

(acetic acid) will neutralize its effects.4) 10 mg Morphine IM injection for relieving pain.5) ICE CUBES to suck to relieve thurst and bring

effects.6) IV Fluids to combat fluid loss.7) Corticosteroids : for shock treatment and to

prevent oesophageal sticture.8) Tracheostomy may be necessary if there is

acute oedema of the glottis.9) Melted Butter10)Magnesium Oxide ( along with general

treatment of poisoning)