Inorganic Corrosive Acids in Agada Tantra

Introduction to Agadha Tantra and Corrosive Poisons

• Subject Context: The study falls under Agadha Tantra and Forensic Medicine. It specifically focuses on corrosive poisons classified as inorganic acids.
• Classification of Corrosive Poisons:
  • Inorganic Acids (e.g., Sulphuric acid, Nitric acid, Hydrochloric acid).
  • Organic Acids.

Sulphuric Acid ($H_2SO_4$)

• Physical Characteristics:
  • Naturally heavy, odorless, colorless, and non-fuming.
  • High commercial grade appearance: Brown-black color.
• Signs and Symptoms of Ingestion:
  • Oral Region: Lips and tongue become swollen immediately upon ingestion.
  • Streaks: Brown-black streaks occur at the angles of the mouth, extending down to the chin.
  • Teeth: Teeth exhibit a chalky white appearance.
  • Gastrointestinal Tract: Corrosion affects the mouth, throat, and esophagus.
  • Pain and Voice: Patients experience a severe burning sensation, dysphagia (difficulty swallowing), pharyngeal pain, and the voice becomes hoarse and husky.
• Vomitus and Internal Damage:
  • Vomit is brown or black in color.
  • The vomit may contain "shreddy" contents, representing the sloughing walls of the stomach.
• Systemic Effects:
  • Circulatory collapse.
  • Results in permanent scarring if the patient survives.
• Toxicological Data:
  • Fatal Dose: $5-10\,ml$.
  • Fatal Period: $12-24$ hours.
• Post-Mortem Appearance:
  • External: Corrosive appearance observed on the mucous membranes of the lips, mouth, throat, and skin. Necrosis is visible where greyish-white tissue turns into a black, leathery texture. Damage is also seen on the hands.
  • Internal: Generally limited to the upper digestive and respiratory systems.
  • Stomach Findings: The stomach turns into a soft, spongy, black mass. This is partly due to the presence of calcium oxalate crystals. While the columnar epithelium of the stomach and esophagus shows relative resistance, they still produce a superficial mucous reaction.

Nitric Acid ($HNO_3$)

• Physical Characteristics:
  • Odorless (though noted to have a choking odor in concentrated forms), clear, heavy liquid.
  • Fuming (unlike Sulphuric acid).
• Chemical Reaction with Tissue:
  • In concentrated form, it combines with organic matter/living tissue to produce a yellow discoloration.
  • This yellowing is caused by the production of picric acid.
• Signs and Symptoms:
  • Abdominal: Significant abdominal distension occurs due to gas formation. This is accompanied by eructations.
  • Discoloration: Yellow staining is visible on the tissue, the crowns of the teeth, and any clothing that comes into contact with the acid.
  • Systemic Markers: Urine turns brown, which is a key diagnostic indicator for $HNO_3$ poisoning.
• Inhalation Effects:
  • Lacrimation (tearing).
  • Photophobia.
  • Dysphonia.
  • Asphyxia.
• Toxicological Data:
  • Fatal Dose: Initially stated as $10-15\,ml$, later confirmed as approximately $5-10\,ml$.
  • Fatal Period: $12-24$ hours.
• Post-Mortem Appearance:
  • General findings are similar to $H_2SO_4$ poisoning but characterized specifically by yellow staining.
  • Mucous Membranes: The esophagus and stomach may show brown or brown-black corrosion due to the formation of acid hematin.
  • Respiratory System: In deaths involving inhalation of fumes, the larynx, trachea, and bronchial tubes are congested. The lungs become edematous (fluid-filled).
• Diagnostic Chemical Test:
  • The Brown Ring Test: Confirmed by adding a strong solution of ferrous sulphate ($FeSO_4$) and sulphuric acid ($H_2SO_4$) to the sample containing nitric acid; a brown ring forms at the junction.

Hydrochloric Acid ($HCl$)

• Physical Characteristics:
  • Colorless and fuming.
  • Characteristic pungent odor.
  • It is a natural constituent of fluids in the stomach and bowel.
• Signs and Symptoms:
  • Generally less corrosive to the skin than nitric acid but highly destructive to mucous membranes.
  • Color Changes: Tissues initially appear grey or grey-white, later turning brown or black due to acid hematin production.
  • Inhalation Symptoms: Intense irritation of the throat and lungs, suffocation, coughing, dyspnea, and cyanosis.
• Chronic Poisoning (Long-term Exposure):
  • Symptoms include "chorizo" (coryza), conjunctivitis, corneal ulcers, pharyngitis, bronchitis, and loosening of the teeth.
• Toxicological Data:
  • Fatal Dose: $15-20\,ml$.
  • Fatal Period: $18-36$ hours.
• Post-Mortem Findings:
  • Stomach contains brownish fluid and the folds of the stomach appear brownish.
  • Perforation of the stomach is rare compared to other acids.
  • Significant findings in the respiratory system include acute inflammation and edema of the lungs and air passages.
• Diagnostic Chemical Test:
  • Mixing the sample with silver nitrate ($AgN_3$) produces a white, curd-like precipitate of silver chloride ($AgCl_2$).

Medico-Legal Aspects and Treatment

• Medico-Legal Status:
  • Sulphuric Acid: Often accidental or suicidal. Homicide is rare because the taste and physical changes in food items are easily detectable. Under BNS 124, acid throwing is classified as injury and hurt.
  • Nitric Acid: Most cases are accidental or suicidal. Homicide is rare due to the taste.
  • Hydrochloric Acid: Mostly suicidal; some accidental or homicidal cases. It is rarely used via vaginal injection for "abortification" (abortifacient purposes).
• Legal Penalties for Acid Attacks (BNS 124):
  • For causing injury/hurt (where the victim does not die): Up to $10$ years of imprisonment plus a fine.
  • For an attempt to throw acid: $5$ to $7$ years of imprisonment.
• General Treatment Protocol:
  • External Cleaning: Wash with water and soap. Application of sodium or potassium carbonate or a paste of magnesium oxide/magnesium carbonate.
  • Eye Exposure: Wash with dilute sodium bicarbonate solution or apply drops of olive oil or castor oil.
  • Internal Early Intervention: Within $30$ minutes of ingestion, provide one-fourth liter of water mixed with milk of magnesia, lime water, or aluminum oxide gel.
  • Contraindication: Gastric lavage must be avoided in corrosive acid poisoning.
  • Antidote/Medication: Prednisolone ($60\,mg$/day) is used to prevent the formation of esophageal restrictions (strictures).

Questions and Discussion

The following terms and concepts were identified by the speaker as requiring further clarification or meaning:

• Excoriated: The speaker noted they did not know the specific meaning of this term in the context of tissue damage.
• Eructation: The speaker requested a definition for this term following the discussion on abdominal distension in nitric acid poisoning.
• Lacrimation, Photophobia, and Dysphonia: The speaker noted they would explain these further as they did not initially know the exact technical definitions during the lecture.
• Chorizo: Noted as a symptom of chronic hydrochloric acid exposure; the speaker requested the meaning of this term (likely referring to Coryza).