Other Names- Hydroxybenzene; Phenol; Benzenol; Phenyl alcohol
Nature
- Carbolic acid is Colourless, prismatic, needle-like crystals that turns pink and liquefies when exposed to air.
- It has sweetish burning taste and phenol like smell.
- Concentrated phenol is a dark brown liquid and contains impurities like cresol.
Uses
- It is used as Antiseptic and disinfectant.
- It is also used for Manufacture of plastic.
Fatal dose
- 2 gm crystals
- 25 to 50 ml of household phenol
Fatal period
3 to 4 hours.
Absorption, metabolism and excretion
- Phenol is absorbed from skin, gastric mucosa, per rectum, per vagina and respiratory tract.
- Phenol is converted into hydroquinone and pyrocatechol and excreted in urine.
- Traces are excreted by lungs, salivary glands, and skin.
Mode of action
- Locally it acts as corrosive agent and when absorbed, it causes CNS depression, metabolic acidosis and renal failure.
- Carbolic acid has great penetrating power and it coagulates protein.
- There is CNS depression, metabolic acidosis, and renal damage.
Sign and symptoms
- Burning pain followed by tingling numbness and anesthesia.
- Nausea and vomiting.
- Respiration is slow and labored.
- Headache
- Giddiness and unconsciousness
- Convulsions
- coma.
- Oliguria and hepatic failure.
- Urine become colorless
- Ochronosis.
Treatments
- Decontaminate skin by copious washing.
- Stomach wash can be done preferably with sodium or magnesium sulfate solution.
- Activated charcoal in the usual manner.
- Treatment of methaemoglobinaemia (with methylene blue).
- Convulsions can be managed with benzodiazepines or barbiturates.
- Supportive measure
Detection test
► Urine collected and stored in a transparent container shows a gradual change in colour to brown or green which indicates the presence of carbolic acid.
► To 10 ml of urine, add 1 ml of 10% ferric chloride. A purple or blue colour which persists even on heating indicates phenol poisoning. Gives green colour which indicates the presence of derivatives of carbolic acid i.e. cresol.
► When 10 ml of urine is boiled with Millon’s reagent, then a red colour is produced which indicates the presence of carbolic acid.
Post mortem findings
- Corrosion of skin, at angle of mouth, chin.
- Corrosions are initially white but turns brown in colour.
- Splashing may be seen.
- Tongue becomes white and swollen.
- Mucosa of stomach is tough, white or gray, corrugated and arranged in longitudinal folds and looks leathery.
- Mucous membrane of mouth, throat, lips are sodden whitened or ash gray .
- Urine on exposure to air turns green.
Medicolegal aspects
- Accidental poisoning.
- Suicidal ingestion.
- Homicide is not possible.
