Hypoxia of the brain: causes, symptoms and diagnosis
Oxygen is the basis of all life on our planet. If without food a person can live for several months, without water for several days, without oxygen – only a few minutes. The deficiency of oxygen sensitive of all organs and tissues in the body, but most of all – the brain, it is called the “critical organ” of hypoxia (oxygen starvation of tissues).
The brain on the intensity of the blood flow takes the first place in the body, it is given 20% of the minute volume of blood flow, and this is a very big number. Without violation of functioning brain tissue can withstand only 4 seconds of acute hypoxia already after 8-12 seconds after cessation of blood flow develops loss of consciousness, after 20-30 seconds it disappears the activity of the cortex of the brain and the person falls into a coma. If you do not establish krovoobraschenie for 4-5 minutes, then the brain will die. Because it is very important to have an idea about what is hypoxia of the brain, the main causes that lead in order to prevent serious consequences.
Causes and types of hypoxia
Hypoxia of the brain is not a single disease, it is a pathological condition which can cause a lot, both external and internal factors. Occurs due to insufficient supply of oxygen to tissues or disorders of its utilization by the cells.
Depending on the causes of hypoxia are:
- Exogenous (hypoxia) is the anoxia that develops in reducing the amount of oxygen in the environment. This happens, for example, when climbing in the mountains. As is known, the degree of saturation with oxygen in the air decreases with each meter, because climbing an untrained person can result in mountain sickness (hypoxic hypoxia). A similar situation may occur with malfunction of the ventilation system in an enclosed space, in submarines, in space suits, in aircraft.
- Respiratory (breathing) is the lack of oxygen in the body, which develops due to disorders in the respiratory organs. For example, bronchial asthma, pneumonia, tumors of bronchopulmonary system, disruption of the respiratory center (overdose of drugs, brain damage and spinal cord), paralysis of respiratory muscles, chest injuries, etc.
- Circulatory (cardiovascular) is oxygen starvation of tissues due to impaired hemodynamics or local blood circulation in the brain. The main causes are heart failure, shock, disturbance of local blood flow due to thrombosis, embolism, atherosclerotic plaque. Last causes can trigger the development of acuteischemic stroke of the brain.
- Hemic (blood) – develops when the violation of oxygen transport blood cells. As is known, the oxygen molecules are delivered to all cells in the associated hemoglobin condition. If blood is not enough red blood cells or hemoglobin (anemia) or impaired binding of hemoglobin with oxygen (poisoning metgemoglobinoobrazovatelami poisons), there is a blood hypoxia.
- Tissue (histotoxic) – develops when the violation of utilization of oxygen by cells, for example, destruction or blockade of the enzyme systems that are involved in tissue respiration (some poisons, medications).
At the time of the development of hypoxia there are several types of it:
- lightning – develops over several seconds and minutes, for example, bleeding in the respiratory center;
- acute – occurs within a few hours, for example, poisoning metgemoglobinoobrazovatelami compounds;
- chronic – lasts a long time, for example, in chronic heart failure, cerebral arteriosclerosis,
The consequences of cerebral hypoxia
Lightning and severe hypoxia of the brain, usually lead to death if not provided with emergency care. In other cases, the consequences of hypoxia depend on the degree and localization of brain tissue damage.
These patients develop a variety of brain disorders, neurological deficit, for example, dizziness, chronic headache, impaired speech, memory, vision, etc. If the patient will undergo adequate rehabilitation, in the future may complete the renewal functions of the brain, but in most cases there are residual effects of various degrees of severity.
Chronic hypoxia has a more favorable prognosis for life, but reduces its quality. The human body has a unique ability to adapt to the changing conditions of existence, including life in the conditions of partial oxygen starvation:
- increases the depth and frequency of breathing (outwardly manifested as shortness of breath), begin operating the reserve, the alveoli in the lungs to increase the area of the “absorption” of oxygen;
- increases heart rate (raises the heartbeat), increased
The symptoms of cerebral hypoxia
Signs of acute hypoxia develop depending on its causes. But there are universal symptoms that are inherent to any kind of hypoxia.
First developed signs of overstimulation of the nervous system, which in a few minutes give way to symptoms of her oppression and loss of consciousness. The patient is agitated, he has rapid breathing andheartbeat, there is euphoria, the skin pale and sticky with cold sweat. Immediately replaced the excitement phase comes the phase of oppression of the cerebral functions – the patient is apathetic, feels dizziness, drowsiness, flashing “flies” before the eyes, at first partially disturbed consciousness (stupor, SOPOR, somnolence), it has a coma of varying depth. Fall first the superficial and then the deep, unconditional reflexes, breathing stops and the heart.
If at this point the patient will be provided with adequate emergency care (resuscitation ABCD principle), then if successful, all functions return exactly the opposite.
The symptoms of chronic hypoxia of the brain is much more diverse. About cerebral insufficiency can think of the next complaints of the patient:
- constant dizziness;
- frequent mood swings;
- persistent headache;
Diagnosis of hypoxia
Diagnostics General hypoxia of an organism is much easier than to establish the diagnosis of local cerebral hypoxia. With this purpose it is enough to analyze the symptoms of the pathology and the clinical history. To assess the degree of reduction in the level of oxygen in the blood with the help of such methods as pulse oximetry (measurement of blood oxygen saturation), the definition of the type of the acid-alkaline balance in the body and the gas composition of venous and arterial blood. These surveys sufficient to establish the occurrence of hypoxia, but in order to find its cause need a larger number of surveys, which are selected depending on the presumed etiology of the condition. For example, MRI for suspicion of a stroke, blood tests in cases of suspected poisoning.
Chronic hypoxia is often not accompanied by a significant decrease of blood oxygen saturation, because the body has time to adapt to pathology and this ischemia is often local (brain). Therefore to establish its causes plays a big role in the history of the disease (which nosological forms hurts people). For example, if there is ischemic heart disease can be suspected cerebral atherosclerosis, and if –
Hypoxia of the brain in newborns
Hypoxia of the brain of the newborn can occur in utero and during childbirth. Among all neonatal pathology, this condition is the most common. Hypoxia severe may lead to the formation of defects of fetal development, preterm birth, intrauterine death of the baby, stillbirth, severe disability and death in the neonatal period.
Among the main reasons for this state include:
- severe obstetric and somatic diseases of the mother(heart failure, intoxication, insufficiency of fetoplacental complex, placental abruption, umbilical cord disease);
- pathology of the fetus and newborn (genetic disease, malformations, infections, cerebral injury of the newborn);
- asphyxia of the newborn at birth, aspiration of amniotic fluid, meconium, birth trauma, swelling of the Airways of the child.
Often, hypoxia of the brain occurs in the fetus when taken by the mother of alcohol, some medicines, when Smoking, drug abuse, in occupational and environmental health hazards. Because from the behavior of the mother affects the health and future of her child.
Treatment of hypoxia of the newborn is a complex task. Carried out immediately after birth resuscitation (release of the upper airway, tactile stimulation and artificial respiration). Further treatment depends on the cause of hypoxia: in prematurity administered surfactants, in traumatic brain injury – and anti-edema therapy, nootropic treatment of the infection with antibiotics.
If you notice any signs of hypoxia of the brain in yourself or your child, then be sure to seek medical attention, because every minute the brain is without oxygen can stand you health or life.
Hypoxia is not a disease but a pathological condition (acute or chronic), which is accompanied by oxygen starvation of the brain and other organs. Causes of hypoxia a lot. Only by eliminating them, you can get rid of the symptoms of hypoxia of the brain.