Carbon monoxide poisoning is a potentially fatal condition caused by inhalation of carbon monoxide, a toxic, colorless, odorless and tasteless gas.
The symptoms are acute and develop rapidly. Unborn fetuses, neonates and young children are more susceptible to harmful effects of carbon monoxide . These include:
Chronic poisoning due to exposure to low concentrations of carbon monoxide is also common. It is seen in cases of occupational exposure to carbon monoxide or in smokers. Even chronic passive smoking can cause these symptoms. The signs of chronic exposure usually disappear on spending time away from workplace or home and may give an indication of carbon monoxide poisoning. The signs and symptoms of chronic poisoning include:
In people with heart problems, respiratory disorders, and anemia and in pregnant women, even minor exposure to carbon monoxide may prove to be fatal. Encephalopathies develop in neonates as a result of carbon monoxide exposure.
Immediate care should be given to the patients .
The prognosis of carbon monoxide poisoning is hard to predict. About 30% of the patients suffer fatal complications due to unavailability of immediate medical care. About 11% of the surviving patients suffer from chronic neurological disorders particularly, memory loss. Longer the exposure to carbon monoxide, poorer is the prognosis. Delay in treatment can also lead to poor outcomes.
Carbon monoxide poisoning is usually accidental and caused by  :
Exact number of accidents and deaths due to carbon monoxide poisoning is unknown and majority of the cases go unregistered. No racial factors are involved. Males are, however, more predisposed to carbon monoxide poisoning due to workplace exposure.
The cases of carbon monoxide poisoning have a seasonal tendency due to use of heaters and burning of wood and coal for keeping warm in the winters.
Once inhaled, carbon monoxide rapidly diffuses across the alveolar membrane and passes into the blood stream to bind to hemoglobin after displacing oxygen. Another oxygen carrying protein, myoglobin, is also bound by carbon monoxide.
Carboxyhemoglobin (HbCO) is formed as a result. Carboxyhemoglobin not only limits the oxygen delivery to the tissues but also decreases the affinity of hemoglobin for normal oxygen . The tissues suffer hypoxic injury as a result of tissue asphyxia. Cardiac output is reduced. Hypotension occurs.
Carbon monoxide also affects the mitochondrial oxidation. It binds to cytochrome oxidase, an enzyme required for normal oxidative process, thereby affecting the energy processes. Cytochrome C and P450 are also affected. Acidosis occurring as a result of carboxyhemoglobin formation leads to hyperventilation and shortness of breath.
Carbon monoxide also causes the release of nitric oxide (NO) from vascular epithelium, leading to vasodilation, leakage of plasma from capillaries and edema. Oxygen free radicals trigger the apoptotic pathway, causing irreversible cell injury if the condition persists for long. In the central nervous system (CNS), demyelination of nerve fibers is interfered with. In brain tissue, areas of necrosis might be seen.
Carbon monoxide (CO) is the gas produced as a result of incomplete oxidation process. It is commonly produced as a by-product during industrial or domestic burning of gasoline, diesel or petrol or coal. The gas is colorless, odorless (therefore, difficult to detect) and has high affinity for hemoglobin in human blood. It is, therefore, aptly known as the “silent killer”. It readily enters the circulation, displacing oxygen from the hemoglobin and depriving the tissues of oxygen. Rapid treatment is usually required in cases of carbon monoxide poisoning to counter its effects .
Improper burning of wood, gas or petrol can cause the formation of carbon monoxide gas which is highly toxic to the human body. It hinders the oxygen supply to the body tissues, posing fatal health problems like difficulty in breathing, dizziness, double vision, lightheadedness, abdominal pain, nausea and vomiting. The person can faint and even go into a coma if not treated immediately.
The gas operated stoves and heaters should be checked regularly to avoid leakage problems. Areas where stoves are burnt should be well ventilated. With proper precautionary measures, carbon monoxide poisoning can be avoided.