I- Overview :
- frequent seasonal poisoning in Algeria.
- Often accidental and collective.
- Immediate or insidious gravity :
- Hundred deaths a year (November to February)
- 300 at 400 annual deaths in France,
- 1000 at 2000 death in the United States (Consultation of thousands in the ER / Intox CO)
- Risk of neuropsychiatric sequelae, long-term, further evaluation difficult.
CARBON MONOXIDE :
- CO is the main product of any incomplete combustion of carbonaceous substances :
C + O2 → CO2
C + ½O2 → CO
- The amount produced depends on the efficiency of combustion and the availability of oxygen during combustion.
- odorless, colorless, tasteless, nonirritating density = 0,976 hence its widely
- A great affinity with HB (240 time)
- Once the bond is formed, unable to fix it and carry F02.
- Decrease of F02 in the blood => tissue anoxia.
- CO binds to hemoglobin and cytochromes.
- Eliminated pulmonary.
- 4-5 H outdoors.
- oxygen isobaric : 1H Vi.
- 20 My one Hyperbaric.
II- CO domestic sources :
- Le Brasero ou Kanoun.
- The water heater improperly installed natural gas: defective unit; Installation unsuited
- The insufficient draft in chimneys.
- The auto ignition engines.
- Inhalation of fire smoke, tobacco, narghile or hookah, etc…
III- The forms forensic :
A- The accidental form :
C & rsquo; is the most common form, they are poisoning that nocturnal and collective character, it mainly occurs with domestic heating.
B- The professional form :
She sees herself in workers, mining smelter, and gas plants, or in metallurgical plants.
C- The suicidal form :
also common and difficult to achieve, it is the prerogative of women and young people nervous, often an association to another is toxic to search.
D- The criminal form :
Exceptional and difficult to achieve.
IV- pathophysiology :
CO is essentially on breathing.
A- Action on hemoglobin :
HbO2 + CO + O2 ↔ HbCO
- As previously described the COHb (carboxyhémoglobine) formed is unable to bring t 02 which has the result acute anoxia.
- And 2/3 hemoglobin is blocked in the form of COHb death is certain.
- However this reaction is reversible and the hemoglobin released is not altered and immediately resumes its role in breathing
B- Action on cellular oxidations :
- CO blocks the cellular oxidations acting directly on the cytochrome oxidase resulting in cell anoxia.
V- The clinic :
A- acute intoxication :
1- The toxic impregnation step :
It is accompanied by neurosensory manifestations type : cephalalgia, fear of heights, nausea, buzzing ear, disorders of hearing and visual, a drunk.
2- The phase of coma :
- This is a deep coma and quiet
- Pupils are miosis
- Tendon reflexes abolished
- The bilateral Babinski's.
- This phase is accompanied by events :
– cutaneous : coloration and lots phlyctène (exceptional).
– Respiratory : bronchial congestion.
– Cardiovascular : collapsed.
3- complications :
- They are many, some appear early and aggravate coma, while others are later and are rather part of the legacy.
a- early :
- PAO and cardiovascular collapse without parallel, or with, disorders of consciousness.
- Rhythm disorders, Death.
- Crises convulsives.
b- late :
- S. Extrapyramidaux : Parkinson.
- S. Complex basal ganglia.
- Mental disorders.
- Sensory disorders : Blindness, deafness, peripheral neuritis.
B- chronic intoxication :
- It is seen especially in industry and in heavy smokers, characterized by the triad of DUVOIR-GAULTIER :
– headaches : fronto-temporal, often times permanent pulsatile.
– Asthenia : early onset and progressive installation.
– Dizziness : can go to syncope.
- This triad can be associated with digestive disorders, heart, neurological or sensory.
WE- Forensic Diagnosis :
A- In the living :
It is based primarily on :
- The history.
- The importance of clinical signs.
- The toxicology assay. (+++)
- Venous blood sampling and measurement of the percentage of COHb from the CO- oximeter :
- and HbCO > 66% some death.
- If COHb around 50% unfortunate prognosis.
- A rate of COHb < 0,8 ml / 100 ml of blood is considered a normal rate.
- A rate of COHb < 5 at lOml / lOOml blood is an important rate (some impregnation).
- A rate of COHb > lOml / lOOml blood is a very serious rate.
B- Among the dead body :
1- external examination :
- Cyanosis of the face and nails.
- Cadaveric lividity have a bright pink or carmine color pink.
- Blood suffusions (bruise subconjunctival, hyperhémie) under the conjunctiva, under the scalp, and in the oral mucosa.
- des phlyctènes (+/-) and pressure sores may appear to support points.
2- at autopsy :
- The brain and meninges are congestive.
- Presence airy spume (mousse d’OAP). The lungs are congested and colorful pink carmine.
- Under the pleura appear Ecchymotic spots. Task TARDIEU
- Muscles have a bright red color.
- Blood is fluid and currant pink color.
3- supplementary examinations :
- The pathological examination : Micro cell foci of necrosis in organs.
- The toxicological examination : (the definitive diagnosis) +++
– the dosage of CO and T COHb
+ Blood heart on tight syringe.
+ Muscle (10 to 15gr) if putrefaction.
– The coefficient of BALTHAZARD = COHb / total Hb If it is equal to 2/3 (66%) => certain death by CO.
Courses of Dr. Ghennam – Faculty of Constantine