This presentation includes: Other names of hydrocyanic acid Physical appearance of cyanides Commercial uses of cyanides Sources of cyanides Mode of action of cyanides Fatal Dose and fatal period of cyanides Acute Poisoning of cyanides Chronic Poisoning of cyanides Diagnosis of cyanides Treatment of cyanides Post-Mortem appearance Medicolegal importance If you like my work then thumb 👍🏻. Thanking in anticipation.

2. HYDROCYANIC ACID (HCN)
PRESENTED BY:
MR. ARSLAN JAMEEL
MR. AHSAN ARSHAD
MR. QAMAR RASHID
PESENTED TO:
DEPARTMENT OF FORENSIC MEDICINE & TOXICOLOGY, FMU FAISALABAD

3. GENERAL INFORMATION
OTHER NAMES:
Cyanogen
Prussic acid
PHYSICAL APPEARANCE:
1. GASEOUS STATE: HYDROGEN CYANIDE,
characterized by peculiar odor of BITTER ALMONDS
2. LIQUID: called as HYDROCYANIC ACID or PRUSSIC
ACID
3. SOLID: Salts of cyanide in the white crystalline
powder.

4. COMMERCIAL USES
INDUSTRIAL:
Electroplating,
metal processing,
extraction of ores,
photographic processes,
production of synthetic rubber
manufacture of plastics
AGRICULTURE: insecticide and rodenticide
MEDICINAL:
oLaetrile: Chemotherapeutic agent for cancer
oSCHEELE’S ACID: used in veterinary medicine contains 4% of the acid
oSODIUM NITROPRUSSIDE: Effective antihypertensive (IV)
LABORATORY: Preparation of Acrylonitrile

5. SOURCES
PLANTS:
Cyanogenic glycosides (Amygdalin)
o Kernels of common cherry
o Peach
o Plum
o Apricot
o Bitter Almonds
COMBUSTION:
oBurning of plastic furniture (Polyurethane),
oBurning of silk or wool
oCigarette smoking
Each cigarette liberates 150-200 ug of HCN

6. MODE OF ACTION
 Inhibits succinic dehydrogenase, superoxide dismutase & carbonic
anhydrase
 Stimulate carotid & aortic bodies resulting in hyperpnea and have a
cardio-toxic role.
.

8. Fatal period
Fatal Dose
Vegetable Acid
Instantaneously
1 part in 2000
Hydrogen cyanide Within few minutes
1 part in 10,000
Within few hours
1 part in 50,000
2-10 min.
50-60 mg
Hydrocyanic acid
30 minutes
100-200 mg
Cyanide Salt
FATAL DOSE & FATAL PERIOD
Potassium Cyanide Hydrogen Cyanide
HCl
Stomach

9. SIGNS AND SYMPTOMS
ACUTE POISONING:
Inhalation:
a) Causes most rapid onset (within seconds),
b) Serious exposure results in comma and death due to
respiratory arrest
Ingestion: Less rapid onset (within minutes)

10. SYSTEMS INVOLVED
GIT:
Burning taste,
Numbness in mouth and
throat,
Salivation,
Frothing,
Nausea,
Vomiting,
Substernal and
epigastric pain
CNS:
Headache,
Dizziness,
Sweating,
Syncope,
Seizures
Comma
Death
Pupils often dilated and
sluggish in reaction

11. RESPIATORY SYSTEM:
Initially:
Tachypnea
Dyspnea
In later stages:
Bradypnoea
Hypopnoea
Irregular respiration
Pulmonary edema
Cyanosis
Respiratory arrest
SYSTEMS INVOLVED
Bitter almond almond smell can be detected in breath

13. CVS:
Initially hypertension with reflex bradycardia followed by
Hypotension
Tachycardia
Arrhythmia
Venous oxygen tension approaches that of arterial blood
because cellular usage of oxygen is blocked
Bright red color of the venous blood is clearly evident on
fundoscopy
Lactic Acidosis:
Blockade of cellular respiration leads to excessive anaerobic
metabolism causes lactic acidosis
SYSTEMS INVOLVED

15. CHRONIC POISONING
Survivors of serious acute poisoning may develop delayed
neurologic sequelae like PARKINSONS DISEASE and TREMORS
TROPICAL ATAXIC NEUROPATHY:
Pheripheral sensory neuropathy
Deafness
Ataxia
Glossitis
Scrotal dermatitis
LEBER’S HEREDITARY OPTIC ATROPY
Sensitivity of optic nerve to cyanide ( congenital deficiency
of Rhodanese)
TOBACCO AMBLYOPIA:
Loss of visual functions, exclusively in heavy smokers

16. DIAGNOSIS
1. Odour of bitter almonds
2. Serum cyanide level (Confirmatory)
 Levels >0.2ug/ml are considered toxic
3. Laboratory findings:
 Serum Lactate level >10 m mol/L
 Arterial blood gas analysis shows normal O2 saturation
and metabolic acidosis
 Elevated venous O2 saturation
4. ECG:
 Bradycardia followed by Tachycardia
5. LEE JONE’s TEST:
 Ferrous Sulphate + 5cc gastric fluid
 Boil and Cool
 Add 8-10 drops of HCl
 Greenish Blue color indicates cyanide

17. TREATMENT
Time is the essence.
 Stabilization:
 Assisted ventilation and 100% oxygen
 cardiac monitoring
 IV excess
 Treatment of metabolic acidosis
 Vasopressors for hypotension
 Decontamination:
 Cutaneous exposure
 Ingestion
 Activated charcoal, cathartics

18. TREATMENT
 Antidote therapy:
Consists of 3 steps Eli Lilly Cyanide kit approach
STEP 1: Amyl nitrite (crushed and inhale for 30 sec.
Step 2: Sodium nitrate 3% soln. slow IV i.e. over 5-10 min.
Hb + amylnitrite / sodium nitrite Methemoglobin
Cyanide + Methemoglobin Cyanomethemoglobin
Cyanide Cytochrome Oxidase complex Cyano-methemoglobin
+ +
Methemoglobin cytochrome oxidase complex
 Nitrite induces methemoglobinaemia which causes the detachment of
cyanide from the haeme group of cytochrome oxidase and binds to it
itself.
 STEP 3: Sodium thiosulphate (25% soln.) 3-5 ml/min. IV
Cyanomethemoglobin+ sodium thiosulphate Thiocynate +
Methemoglobin+ sulphate

19. TREATMENT
Other Antidotes:
Dicobal edetate or tetracemate can be used I/V
followed by 20 ml of 50% glucose
Hydroxocobalamin
METHYLENE BLUE is NOT an antidote for cyanide.

20. POST MORTEM APPEARNCE
EXTERNAL APPEARNCE:
Features
External Parts
Bitter almonds
Odor
Brick color
Skin & mucous
membrane
Bright, glistening
with dilated pupils
Eyes
Firmly closed
Jaws

21. POST MORTEM APPEARNCE
INTERNAL APPEARNCE:
Feature
Organ or Tissue
odor
Brain Tissue
Blood strained froth
Trachea & Bronchi
Pulmonary edema
Lungs
Congested with hemorrhagic gastritis
Bright red to brown (Potassium
Cyanide)
Stomach & Intestinal Mucosa
 Congestion
 Minute necrosis & hemorrhage
 Degenerative changes as whole
Brain
Lenticular nuclei
Disseminated petechiae
Brain, meninges, pleura,
lungs & Pericardium
Corroded by cyanide salts
Lips, mouth
Presence of RBC’s
Spleen

22. MEDICOLEGAL IMPORTANCE
Suicidal agents
Accidental poisoning (Fumigation or Disinfection)
Accidental cattle poisoning
Judicial execution (Hydrocyanic acid)
Given to Rasputin in a pastry

23. REFRENCES
 Practical Note Book On Forensic Medicine & Toxicology
 Images from Web & Medicosis Perfectionalis