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By
Dr. Safaa El-ShanawanyProfessor of Forensic Medicine
& Clinical Toxicology
By
Dr. Safaa El-ShanawanyProfessor of Forensic Medicine
& Clinical Toxicology
RODENTICIDES
Learning Objectives:
Define the nature of rodenticides
Identify the major classes of rodenticides
Recognize the pathophysiology of some rodenticides
Describe signs and symptoms of their toxicity
Assess severity of poisoning by different methods of investigations
Treat rodenticide poisoning and specify antidotes
RODENTICIDES
Learning Objectives:
Define the nature of rodenticides
Identify the major classes of rodenticides
Recognize the pathophysiology of some rodenticides
Describe signs and symptoms of their toxicity
Assess severity of poisoning by different methods of investigations
Treat rodenticide poisoning and specify antidotes
Use of rodenticides : to kill rodents and insects
Types: anticoagulant and non-anticoagulant.
Anticoagulant rodenticides
Use of rodenticides : to kill rodents and insects
Types: anticoagulant and non-anticoagulant.
Anticoagulant rodenticides
Coumarin derivatives
Hydroxy C. 4-H.C.
e.g warfarin
Regular warfarins:
Massive or repeated doses
Toxic
Indandiones
Super warfarins:
Single, small dose
Prolonged, powerful toxic
effect
Coumarin derivatives
Hydroxy C. 4-H.C.
e.g warfarin
Regular warfarins:
Massive or repeated doses
Toxic
Indandiones
Super warfarins:
Single, small dose
Prolonged, powerful toxic
effect
Pathophysiology
1) Interference of activation of vit k-dependent factors: II, VII, IX, X
2) Direct capillary damage
1) , 2) bleeding tendencies
Clinical picture
Onset: 8-12 hours 1-3 days
Pathophysiology
1) Interference of activation of vit k-dependent factors: II, VII, IX, X
2) Direct capillary damage
1) , 2) bleeding tendencies
Clinical picture
Onset: 8-12 hours 1-3 days
BleedingMinor life threatening
Epistaxis - gums - hematomas –
Hemoptysis - hematuria - vaginal bleeding
GIT bleeding
Intracranial hemorrhages.
Investigations
Identify the type (box)
P.T, INR
Monitoring of P.T in long acting (super warfarins)
CBC, blood grouping
Vit K-dependent factors
Rodenticide screening (RIA, HPLC, GC-MS)
BleedingMinor life threatening
Epistaxis - gums - hematomas –
Hemoptysis - hematuria - vaginal bleeding
GIT bleeding
Intracranial hemorrhages.
Investigations
Identify the type (box)
P.T, INR
Monitoring of P.T in long acting (super warfarins)
CBC, blood grouping
Vit K-dependent factors
Rodenticide screening (RIA, HPLC, GC-MS)
Treatment
1-A.B.C.
2-Decontamination:
No emesis (Fear of hemorrhage)
Gastric lavage then activated charcoal + cathartic esp. in
super warfarins.
3-Transfusion of fresh blood or fresh frozen plasma.
4-Vit K1 :
1-5 mg in child, 5mg in adult s.c/oral.
Action after several hours, may need blood transfusion first.
Treatment
1-A.B.C.
2-Decontamination:
No emesis (Fear of hemorrhage)
Gastric lavage then activated charcoal + cathartic esp. in
super warfarins.
3-Transfusion of fresh blood or fresh frozen plasma.
4-Vit K1 :
1-5 mg in child, 5mg in adult s.c/oral.
Action after several hours, may need blood transfusion first.
Non anticoagulant rodenticides
They are more serious and may cause death as a result of single
ingestion. They are divided into three groups according to toxicity.
Highly toxic:
Arsenic, phosphorus, strychnine, thallium, and zinc phosphide.
Moderately toxic:
ANTU (α- naphthyl thiourea)
Low toxic:
Norbormide and red squill.
Non anticoagulant rodenticides
They are more serious and may cause death as a result of single
ingestion. They are divided into three groups according to toxicity.
Highly toxic:
Arsenic, phosphorus, strychnine, thallium, and zinc phosphide.
Moderately toxic:
ANTU (α- naphthyl thiourea)
Low toxic:
Norbormide and red squill.
Zinc phosphide
It is dark gray crystalline powder with rotten fish odor.
Pathophysiology:
Zinc phosphide reacts with water and hydrochloric
acid in the stomach producing phosphine gas which
causes systemic toxicity.
Zinc phosphide
It is dark gray crystalline powder with rotten fish odor.
Pathophysiology:
Zinc phosphide reacts with water and hydrochloric
acid in the stomach producing phosphine gas which
causes systemic toxicity.
Clinical picture:
GIT: Nausea, vomiting, abdominal pain ,
diarrhea, black in color.
Respiratory: Rotten fish odor of breath, chest
tightness, cough, dyspnea, crepitations,
pulmonary edema and subpleural
hemorrhage.
CVS: Hypotension, shock, arrhythmia
CNS: Ataxia, seizures,coma.
Hepatorenal toxicity
Others: Hypocalcemia, tetany, renal failure.
Clinical picture:
GIT: Nausea, vomiting, abdominal pain ,
diarrhea, black in color.
Respiratory: Rotten fish odor of breath, chest
tightness, cough, dyspnea, crepitations,
pulmonary edema and subpleural
hemorrhage.
CVS: Hypotension, shock, arrhythmia
CNS: Ataxia, seizures,coma.
Hepatorenal toxicity
Others: Hypocalcemia, tetany, renal failure.
Treatment:1. A-B-C
2. Dilution with milk or starch then gastric lavage with
sodium bicarbonate to alkalinize the gastric
environment and decrease the conversion of phosphide
to phosphine.
3. Activated charcoal decreases absorption of phosphide.
4. Symptomatic treatment:
Diazepam for seizures
Ca gluconate or chloride I.V for tetany.
5. Ca Na2 EDTA: may have a role.
Treatment:1. A-B-C
2. Dilution with milk or starch then gastric lavage with
sodium bicarbonate to alkalinize the gastric
environment and decrease the conversion of phosphide
to phosphine.
3. Activated charcoal decreases absorption of phosphide.
4. Symptomatic treatment:
Diazepam for seizures
Ca gluconate or chloride I.V for tetany.
5. Ca Na2 EDTA: may have a role.
STRYCHNINE It is a very bitter crystalline powder obtained by
crushing strychnous nux vomica seed. The active principles are mainly strychnine and
brucine, but strychnine is 20 times more potent.
Uses
STRYCHNINE It is a very bitter crystalline powder obtained by
crushing strychnous nux vomica seed. The active principles are mainly strychnine and
brucine, but strychnine is 20 times more potent.
Uses
Medical:
Not used nowadays due
to its toxic effects. Only
as vermicide in veterinary
medicine.
Medical:
Not used nowadays due
to its toxic effects. Only
as vermicide in veterinary
medicine.
Non medical:
Rodenticide & a common
adulterant of many street
drugs as cocaine and
marihuana.
Non medical:
Rodenticide & a common
adulterant of many street
drugs as cocaine and
marihuana.
Circumstances of poisoning:Accidental:
By accidental ingestion of rodenticides by children
Suicidal:By pharmacists, medical personnel and agricultural workers.
Homicidal:Is very rare due to its bitter taste and rapid action. Sporadic
cases do occur by giving the poison with alcohol or foods
which normally have a sour taste.
Circumstances of poisoning:Accidental:
By accidental ingestion of rodenticides by children
Suicidal:By pharmacists, medical personnel and agricultural workers.
Homicidal:Is very rare due to its bitter taste and rapid action. Sporadic
cases do occur by giving the poison with alcohol or foods
which normally have a sour taste.
Pathophysiology:It is a convulsing poison. Convulsions result from either:
Pathophysiology:It is a convulsing poison. Convulsions result from either:
Strychnine mainly produces its effect by blocking of
inhibition, so any stimulus will pass to all motor cells.
Strychnine competes with the neuro-transmitter glycine
(anti convulsing) for specific receptors (mainly in the spinal
cord, brain stem and thalamus).
Strychnine opposes GABA (gamma amino butyric acid)
which produces inhibition at presynaptic sites.
Strychnine mainly produces its effect by blocking of
inhibition, so any stimulus will pass to all motor cells.
Strychnine competes with the neuro-transmitter glycine
(anti convulsing) for specific receptors (mainly in the spinal
cord, brain stem and thalamus).
Strychnine opposes GABA (gamma amino butyric acid)
which produces inhibition at presynaptic sites.
Blocking of
inhibition.
Blocking of
inhibition.
Enhancing of
excitation.
Enhancing of
excitation.
Clinical picture:Clinical picture:
Symptoms begin 15 to 30 minutes after ingestion.
The patient is restless, apprehensive
Symptoms begin 15 to 30 minutes after ingestion.
The patient is restless, apprehensive
Muscles stiffness especially back and neck
Tremors and twitches
Muscles stiffness especially back and neck
Tremors and twitches
Sudden onset of convulsions characterized by: Painful.
Phasic (contraction followed by relaxation)
Diffuse (all muscles of the body ).
Symmetric (both sides of the body).
Extensor thrust (extensor group of muscles being
stronger will predominate).
Sudden onset of convulsions characterized by: Painful.
Phasic (contraction followed by relaxation)
Diffuse (all muscles of the body ).
Symmetric (both sides of the body).
Extensor thrust (extensor group of muscles being
stronger will predominate).
The end result will beThe end result will be
Arched back position
(opisthotonus) i.e.
hyperextension of
spines.
Arched back position
(opisthotonus) i.e.
hyperextension of
spines.
Contraction of muscles
of expression -----> bitter
smile expression
(risus sardonicus).
Contraction of muscles
of expression -----> bitter
smile expression
(risus sardonicus).
Contraction of the
muscle of the jaw
(locked jaw).
Contraction of the
muscle of the jaw
(locked jaw).
The abdominal and respiratory muscles are
involved in the generalized convulsions with
The abdominal and respiratory muscles are
involved in the generalized convulsions with
Bulging of the eye balls.
Cyanosis
temperature
B.P
Bulging of the eye balls.
Cyanosis
temperature
B.P
Pulse
Consciousness is
retained till the end
with severe agony
Pulse
Consciousness is
retained till the end
with severe agony
The fit remains for 1-2 minutesThe fit remains for 1-2 minutes
Complete muscle
relaxation
typically occurs
Complete muscle
relaxation
typically occurs
Between convulsionsBetween convulsions
Breathing
resumes
Breathing
resumes
Profuse
sweating
Profuse
sweating
The patient may fall asleep from exhaustion or will be anxious about a recurrence of the attack, with a fear of impending death.
The relaxation phase remains for 5 - 15 minutes. Then another paroxysm will occur provoked by any
sudden sensory stimulus (auditory, visual). Death usually follows 4 or 5 of such convulsions.
The patient may fall asleep from exhaustion or will be anxious about a recurrence of the attack, with a fear of impending death.
The relaxation phase remains for 5 - 15 minutes. Then another paroxysm will occur provoked by any
sudden sensory stimulus (auditory, visual). Death usually follows 4 or 5 of such convulsions.
Complications:
Complications of strychnine poisoning are due
to profound muscle spasms:
Lactic acidosis
Rhabdomyolysis
Hyperthermia
Complications:
Complications of strychnine poisoning are due
to profound muscle spasms:
Lactic acidosis
Rhabdomyolysis
Hyperthermia
Diagnosis:1.Circumstantial evidence
2.History of:
Sudden appearance of the paroxysm in a healthy person.
Negative history for any injury or disease and the attack is
directly related to the intake of medicine or ingestion of food or
drink.
3.Clinical diagnosis: occurrence of sudden, phasic, painful, diffuse,
symmetric, extensor thrust.
4.Laboratory diagnosis: by thin layer chromatography , even after
death as it resists putrefaction
Diagnosis:1.Circumstantial evidence
2.History of:
Sudden appearance of the paroxysm in a healthy person.
Negative history for any injury or disease and the attack is
directly related to the intake of medicine or ingestion of food or
drink.
3.Clinical diagnosis: occurrence of sudden, phasic, painful, diffuse,
symmetric, extensor thrust.
4.Laboratory diagnosis: by thin layer chromatography , even after
death as it resists putrefaction
Differential diagnosis:
From other causes of convulsions:
Traumatic.
Pathological (meningitis, epilepsy).
Toxic e.g. organophosphorous and carbamate insecticides,
carbolic acid, oxalic acid poisoning ... etc.
The most important D.D. is from tetanus by:
Differential diagnosis:
From other causes of convulsions:
Traumatic.
Pathological (meningitis, epilepsy).
Toxic e.g. organophosphorous and carbamate insecticides,
carbolic acid, oxalic acid poisoning ... etc.
The most important D.D. is from tetanus by:
STRYCHNINESTRYCHNINETETANUSTETANUS
• HistoryHistory• OnsetOnset
• ConvulsionsConvulsions• Pause between attacks or Pause between attacks or
(relaxation)(relaxation)• PrognosisPrognosis
• Chemical analysisChemical analysis• Bacterial analysisBacterial analysis
Intake of drugIntake of drugSudden Sudden
Generalized from the startGeneralized from the startPresent and completePresent and complete
Fatal within Fatal within ½½ - 2 hours - 2 hours StrychnineStrychnine
-ve-ve
InjuryInjuryGradual Gradual
Start in the jawStart in the jawAbsent as the convulsions are tonic Absent as the convulsions are tonic
and the muscles remain rigidand the muscles remain rigidDeath within few daysDeath within few days
-ve-veTetanic bacilliTetanic bacilli
Treatment:Strychnine antagonists
Treatment:Strychnine antagonists
control convulsions and prevent asphyxia by control convulsions and prevent asphyxia by
Diazepam 5 - 10 mg IVDiazepam
5 - 10 mg IV
Could be repeated
every five minutes
up to five times.
Could be repeated
every five minutes
up to five times.
Phenobarbital 5 mg/kg IV
Phenobarbital 5 mg/kg IV
Every 5 min until convulsions
resolve. If no response within
20 min give the anesthetic dose
of Phenobarbital preceded by
intubations and artificial
ventilation.
Every 5 min until convulsions
resolve. If no response within
20 min give the anesthetic dose
of Phenobarbital preceded by
intubations and artificial
ventilation.
Muscle relaxantMuscle relaxant
Succinyl choline
10-50 mg IV.
Succinyl choline
10-50 mg IV.
Prevent recurrence of convulsionsPrevent recurrence of convulsions
Keeping the patient in dark quiet room to block the sensory
stimuli
Keeping the patient in dark quiet room to block the sensory
stimuli
Put ear plugsPut ear plugs keep him under observation of a reliable nurse.
keep him under observation of a reliable nurse.
Respiratory supportRespiratory support
Patent clear air way
Patent clear air way
Artificial respiration may be needed.
Artificial respiration may be needed.
Decrease absorption Decrease absorption
Gastric lavage using any alkaloid antidote.Gastric lavage using any alkaloid antidote.
(Preceded by endo tracheal intubations) (Preceded by endo tracheal intubations)
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