Carbolic acid is obtained from coal tar by fractional distillation having(phenolic odour) Properties: Pure carbolic acid consists of cong, colourless,needle like crystals.white turn pink on expsure to light. It is freely soluble in boiling water,alcohol &oils. Crude commercial carbolic acid is a dark brown liquid containing impurities like cresol.
House hold phenol contains 5% phenol in water but never turns blue litmus paper red have no acid reaction.however It forms carbolates (salts)when acted upon by strong bases. Phenol absorption: It can be the result of cutaneous exposure,inhalation of its vapours and ingestion
Fatal dose; (10_15mg the usual range of fatal dose) Fatal period: (death may occur with in few hours due to respiratory or circulatory faliure or with in some days due to reusual involvement)
Poisoning from carbolic acid is known as carblism. 1:skin exposure may burning sensation followed by tingling,numbers & anesthesia a white paque eschar is produced that falls off in a few days leaving a brown stain. 2:Inhalation of carbolic acid vapours causes respiratory tract effects in the form laryngeal pulmonary oedema leading to distressed breathing & cyanosis.
After ingestion strong odour of carbolic acid in the patients mouth.swalloing of acid causes burning sensation in the mouth and throat,abdominal pain vomiting.the mucous membranes of the lips and the mouth become hard and white. Owing to its rapid absorption,gastrointestinal symptoms,giddiness and insensibility deepening to coma may be shown. In CNG stimulation pupils small & contracted, the temperature drops to subnormal,the skin become cold and clammy,respiration slow & pulse small & thready
Metabolic acidosis occurs in sever cases. 5:Renal faliure may occur due to direct toxicity as well as due to oliguria & albuminuria Urine turns slightly greenish. The urine contains trace of free carbolic acid and product of phenol((urine turns dark smelly green because of oxidisation of the substance)) 6:The scanty urine contains albumin and blood casts because of sever irritation of kidney.all these urinary findings grouped together under the term.(carboluria)
Carboluria : Is used to serve as warning of toxic action of carbolic acid,when it was being used as an antiseptic dressing in the past.
Diagnosis: 1:Urine may show RBCS, proteins and casts 2: Add few drops of 10% ferric chloride in urine(aviolet) or blue color indicates the presence of phenol compounds 3:The urine containing carbolic acid also reduces benedict and fehling solution
MANAGEMENT 1:Skin area should be washed with soap solution or 25 %alcoholic solution or vegetable oil or castor oil. 2:Gastric lavage 3:Alcohol has an advantage in that it dissolve and excrete phenol from the mucus membrane and sub mucous layer of stomach. 4:Sodium and magnesium sulfate solution can be used for the lavage
POSTMORTEM APPEARENCES EXTERNALLY,skin appears reddish white in contaminated (a)areas,necrosed and ulcerated. These changes are notable at the sites like fingers,angles of mouth,lips, chin etc (b)The mucous membrane of mouth in hyperaemic with desquamation and hemorrhagic points (c)Phenolic odour is perceptible.
INTERNALLY, (a)Oesophagus and mucous membrane of the stomach shows reddish parchment and prominent rugae.It is thickened,more or less brownish in color,looks leathery. (b)The contents appear dark brown mixed with mucous membrane imparting smell like phenol. (c)Perforation of stomach,necrosis,hardening,parchmentation.Irritation signs will be found in stomach and upper part of small intestine. (d) Heart may appear flabby ( e)Degenerative changes become apparent in the liver and the kidney,if the death is prolonged.
MEDICOLEGAL ASPECTS 1:PHENOL was at time a popular suicidal agent. 2:phenol is rarely used for homocidal purposes in drinking water and even baked in bread but its phenolic odor renders such attempts abortive. 3:Accidental poisoning is uncommon(it may be occur through taking crude acid by mistake) 4:It also happened accidently by its medicinal use 5:children may take it as accidently as household disinfectant 6:chronic intoxication by inhalation of vapors by industrial source.
7:Phenol in dilution also used to cause abortion. 8:During life,the burn upon lips,chin,and cheeks due to bleached and hardened epidermis(appear white) 9:After death on drying these burns will undergo the usual darkening and parchmentising. 10:Engel estimated the quantity of carbolic acid excretedby the healthy man living on a mixed diet is(15 mg in 24hrs).