CLINICAL TOXICOLOGYLecture 2

EVIDENCES OF POISONING1. Circumstantial or Moral evidence – that which are

contributed by the circumstances or deduced from various occurrences and facts.

2. Symptomatic evidences – those that are contributed by symptoms.

EVIDENCES OF POISONING3. Chemical evidences – the evidences obtained by means of

chemical analysis of the substances supposed to have caused the poisoning, or of what has been vomited, or of materials found in some part of the body, or in its excretion.

Ex. a. Ptomaines (animal alkaloids, cadaveric alkaloids, or putrefactive alkaloids) – are alkaloidal substances resulting from the decomposition of albuminous materials under the influence of bacteria.

Ptomaine

EVIDENCES OF POISONINGEx. a. ptomaines (animal alkaloids, cadaveric

alkaloids, or putrefactive alkaloids) – some poisonous, but the majority are not.b. tyrotoxin – any toxin developed in cheese or milk by a bacillus.c. tyrotoxicon – a poisonous crystalline ptomaine or diazobenzene hydroxide, sometimes occurring in stale milk, cheese, and ice cream.

TYROTOXIN

EVIDENCES OF POISONINGEx.

d. Toxin – is a substance (poisonous) or mixture of substances produce by disease – producing microorganisms (Diptheria toxin, tetanus toxin, botulinum toxin, which can cause food poisoning)

Certain food, when undergoing decomposition, may become poisonous by the development of ptomaines or toxins. Symptoms of food poisoning are usually those of GI irritation.

BOTULINUM TOXIN

TETANUS TOXIN

EVIDENCES OF POISONING4. Ante – mortem evidences – are those evidences obtained

before death.5. Post – mortem evidences – are those obtained by an

examination of the organs and tissue of the body after death.

Some POST – MORTEM signs that would help the investigator:

Lesions in the mouth1. Blackening and severe corrosion – sulfuric acid2. Severe corrosion without blackening – hydrochloric acid3. Severe corrosion with yellow stains not removable by ammonia – Nitric acid4. Lips discolored, tongue sodden and mucous membrane eroded – caustic alkali

LESIONS: MOUTH SULFURIC ACID

Some POST – MORTEM signs that would help the investigator:

Lesions in the mouth5. Lips swollen, raw tongue, esophagus white with red crack, then bronchopneumonia if death is delayed – ammonia.6. Mucous membrane whitened – oxalic acid7. Scalded appearance of the mouth – acetic acid8. White stains on lips becoming brown on exposure to air - phenol

SCALDED APPEARANCE ON MOUTH

ACETIC ACID

Some POST – MORTEM signs that would help the investigator:

Lesions in the mouth9. Blue or black line on the gums – lead or bismuth10. Yellow stains on the lips, soluble in ammonia – iodine11. Reddening of the mucous membrane of the mouth and eyes – formalin12. Inflammation sometimes accompanied by dessication - cantharides

LESIONS: MOUTH BISMUTH

Some POST – MORTEM signs that would help the investigator:

Lesions of the GIT:1. corrosion – strong acids2. soapiness – strong alkali3. Hardening of the mucosa with hemorrhage – formalin4. Dark brown gelatinous mass on the stomach walls which may retain white or yellow particles – arsenic5. Mild irritation with green stains - copper

CORROSIONS IN GIT

Some POST – MORTEM signs that would help the investigator:

Lesions of the GIT:6. Acute irritation with chocolate – colored blood – chlorates7. Acute irritation with green stains – chromates8. Congestion, reddening of the mucous membrane – barium salts

BARIUM SALTS

Some POST – MORTEM signs that would help the investigator:

Lesions in the liver and kidney:1. Fatty degeneration – phosphorous2. Inflammation of the kidneys suffused with blood – cantharides

EVIDENCES OF POISONING6. Experimental evidence – evidence obtained by

administering the suspected substance to some living animals and observing the effects.

Discoloration of feces and urine that will help the investigator to identify the poison:

Discoloration of feces:1. Antacids - whitish or speckling2. Anticoagulants - red to black3. Bismuth - black4. Iron preparations - black5. Pirvinium pamoate - red6. Rifampicin - orange to red7. Salicylates - red to black

Discoloration of feces and urine that will help the investigator to identify the poison:

Discoloration of urine:1. Cascara sagrada - red in alkaline urine2. Chloroquine - yellow to brown3. Chlorpromazine - pink to red4. Furazolidone - yellow to brown5. Metronidazole - dark6. Nitrofurantoin - yellow to brown7. Riboflavin - yellow

Discoloration of feces and urine that will help the investigator to identify the poison:

Discoloration of urine:8. Rifampicin - yellow9. Levodopa - darkening of urine on standing10. Methyldopa - red to black11. Phenytoin - pink to red to red-

brown12. Quinine - brown to black

Discoloration of feces and urine that will help the investigator to identify the poison:

Discoloration of urine:13. Sulfonamide - rust yellow or brownish14. Warfarin sodium- orange

EFFECTS OF POISON Poisons may have local or remote effects or both. Local effects of a poison is the impression made

directly upon that part of the body with which the poison comes in contact.

Three kinds of Local effects:1. Corrosion or chemical destruction – is illustrated by the

effect of strong mineral acids or alkalies.2. Irritation or inflammation – which ranges from simple

redness in its mildest form to ulceration or gangrene in its more severe form.

3. Specific effect – is shown by the effect on the extremities of the nerves as felt on the local application of prussic acid and aconite.

EFFECTS OF POISONThe remote effects are those influencing

organs at some distance from the part to which the poison has been applied.

Ex. Narcotic effect of opium on the brain after being taken into the stomach.

The usual symptoms of poisoning are the remote effects of the poison.

EFFECTS OF POISONCertain poisons, such as arsenic and potassium

cyanide have both local and remote effects.

Arsenic has local effects upon the stomach and a remote effect upon the brain.

Cantharides locally produces blisters and remotely influences the kidney and bladder causing strangury and sometimes blood urine.

CANTHARIDES

LOCALIZATION OF POISONSThe remote action of poisons following

absorption on certain organs more than others is “localization of poisons.”

For ex. Opium, morphine, barbiturates, alcohol = affect the brain

digitalis involves the heartstrychnine involves the spinal cordchlorine (in gaseous form), affect

the lungs

ALCOHOL POISONING

OPIUM

Conditions influencing the absorption of Poisons:

Time of absorption varies from few seconds to several weeks.

The rapidity of absorption depends upon the following factors:

1. The solubility of the poison2. The character of the surface to which the poison

is applied3. The quantity of blood in the blood vessels

Conditions which modify the action of POISONS

With reference to the individual1. Physical state2. Age3. Sex4. Idiosyncrasy 5. Habit6. Mental and physical state of the individual7. Condition of the stomach8. The character and amount of stomach

contents

Conditions which modify the action of POISONS

With reference to the poisonous substance1. Mode of administration of the drug2. Size of the dose3. Association with other poisons

MOA OF POISONS1. Receptor Theory2. Changes in Enzyme system3. Changes in membrane structure