toxicology general prinicpals of poisoning

1. GUT DECONTAMINATION
SUBMITTED TO:-
MR. ARINJAY JAIN
SUBMITTED BY:-
NEHA PATHAK
(TPH1812011)
INSHARAH KHAN
(TPH1812012)

2. GUT
 The various methods of poison removal from the
gastrointestinal tract include:
■ Emesis
■ Gastric lavage
■ Catharsis
■ Activated charcoal
■ Whole bowel irrigation

3. EMESIS
 The method of inducing a poisoned patient
to vomit is administration of syrup of ipecacuanha
(or ipecac).
 Source—Root of a small shrub (Cephaelis ipecacuanha
or C. acuminata) which grows well in West Bengal.
 Active principles: Cephaeline, emetine, and traces of
psychotrine.

4. Mode of action:
 Local activation of peripheral sensory receptors in the
gastrointestinal tract.
 Central stimulation of the chemoreceptor trigger zone
with subsequent activation of the central vomiting
centre.
Dose:- 30 ml (adult), or 15 ml (child), followed by 8 to 16
ounces, i.e. 250 to 500 ml approximately, of water

5.  The patient should be sitting up. If vomiting does not occur
within 30 minutes, repeat the same dose once more. If there is
still no effect,
perform stomach wash to remove not only the ingested poison
but also the ipecac consumed.
Complications:
1. Cardiotoxicity
2. Aspiration pneumonia.
3. Oesophageal mucosal or Mallory Weiss tears
Contra-indications:
– Very young (less than 1 year), or very old patient
– Pregnancy
– Heart disease
– Bleeding diathesis
– Ingestion of cardiotoxic poison
– Time lapse of more than 6 to 8 hours

6. GASTRIC LAVAGE
 Defined as “GI decontamination technique, that aims to
empty stomach of toxic substances, by SEQUENTIAL
ADMINISTRATION and ASPIRATION of small volumes of
fluid via OROGASTRIC TUBE”
 Used for people, who:
a. Have consumed a life-threatening dose
b. Exhibit morbidity within 1-2 hours of ingestion
 Beyond 1-2 hours of ingestion, gastric lavage is permitted in
the following conditions:
a. Sustained release preparations
b. Delayed gastric emptying

7.  Lavage should be considered only if a patient has ingested a life-
threatening amount of a poison and presents to the hospital
within 1 to 2 hours of ingestion.
Precautions
 Never undertake lavage in a patient who has ingested a non-toxic
agent.
 Never use lavage as a deterrent to subsequent ingestions.
Contraindications
Haemorrhagic diathesis, oesophageal varices, recent surgery,
advanced pregnancy, ingestion of alkali, coma.
Complications
 Aspiration pneumonia.
 Laryngospasm.
 Sinus bradycardia and ST elevation on the ECG.
 Perforation of stomach or oesophagus (rare)

8. CATHARSIS
 Catharsis is a very appropriate term when used in connection with
poisoning, since it means purification.
 It is achieved by purging the gastrointestinal tract (particularly the
bowel) of all
poisonous material.
 The two main groups of cathartics* used in toxicology include
Ionic or Saline:
These cathartics alter physico-chemical forces within the intestinal
lumen leading to osmotic retention of fluid which activates motility
reflexes and enhances expulsion.
Saccharides:
Sorbitol (D-glucitol) is the cathartic of choice in adults because of
better efficacy than saline cathartics, but must not be used as far as
possible in young children owing to risk of fluid and electrolyte
imbalance (especially hypernatraemia)

9. Contraindications:
– Corrosives
– Existing electrolyte imbalance
– Paralytic ileus
– Severe diarrhoea
– Recent bowel surgery
– Abdominal trauma
– Renal failure.

10. ACTIVATED CHARCOAL
 Activated charcoal is a fine, black, odourless, tasteless
powder made from burning wood, coconut shell, bone,
sucrose, or rice starch, followed by treatment with an
activating agent
Dose:-1 gm/kg body weight (usually 50 to 100 gm in an adult,
10 to 30 gm in a child).
Contraindications
Absent bowel sounds or proven ileus
Small bowel obstruction
Caustic ingestion
Ingestion of petroleum distillates.

11. Mode of action
Decreases the absorption of various poisons by adsorbing them on
to its surface.
Activated charcoal is effective to varying extent, depending on the
nature of substance ingested.
Disadvantages
 Unpleasant taste
 Provocation of vomiting
 Constipation/diarrhoea
 Pulmonary aspiration
 Intestinal obstruction (especially with multiple-dose activated
charcoal)

12. WHOLE BOWEL IRRIGATION
 This is a method that is being increasingly
recommended for late presenting overdoses when
several hours have elapsed since ingestion. It involves
the instillation of large volumes of a suitable solution
into the stomach in a nasogastric tube over a period of
2 to 6 hours producing voluminous diarrhoea.

13. Procedure
 Insert a nasogastric tube into the stomach and instil one of
the recommended solutions at room temperature, at a rate of 2
litres per hour in adults, and 0.5 litre per hour in children.
 The patient should preferably be seated in a commode. The
use of metoclopramide IV, (10 mg in adults, 0.1 to 0.3 mg/
kg in children) can minimise the incidence of vomiting.
 The procedure should be continued until the rectal effluent is
clear, which usually occurs in about 2 to 6 hours.
Complications
 Vomiting
 Abdominal distension and cramps
 Anal irritation.
Contraindications
 Gastrointestinal pathology such as obstruction, ileus,
haemorrhage, or perforation

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