Many complications can develop in patients in intensive care. One of these most severe conditions is Mendelssohn's syndrome.
What is this pathology?
Mendelssohn's syndrome most often refers to obstructive pulmonary disease with damage to the lung tissue (pneumonitis), which develops against the background of gastric juice entering the respiratory tract. This condition was first described in 1946. It is observed in severe patients who have undergone traumatic brain injury, abdominal operations (especially on the abdominal organs) and childbirth. In most cases, the culprit of this kind of pathology is anesthesia (due to it, smooth muscle relaxation occurs).
Against the background of relaxed and lost muscle tone, aspiration (entering the respiratory tract) of the contents of the stomach (usually only gastric juice) occurs. As a result of this, both the bronchial tree and the lung tissue are affected. The condition is extremely serious, can lead to death if appropriate assistance is not provided. It is worth exploring in more detail whysuch an unpleasant disease and what to do about it.
Reasons
Several diseases can lead to the development of Mendelssohn's syndrome. These include:
- Pathologies of the nervous system (severe brain injury, glossopharyngeal nerve damage, increased nervous regulation of the parietal cells of the stomach and motility of the hollow organs of the gastrointestinal tract).
- Diseases of the digestive tract (hiatal hernia, achalasia cardia).
- Respiratory tract disease (short trachea, fistula between esophagus and windpipe).
In addition to the listed ailments, serious diseases can lead to pneumonitis. Abdominal operations (due to a decrease in the tone of the muscles of the organs and its contraction in the opposite direction to the waves of peristalsis) and pregnancy (due to the displacement of the diaphragm) also have a considerable influence on the development of aspiration. For example, surgical interventions account for up to 70% of cases.
However, the most common cause of gastric acid entering the lower respiratory tract is passive leakage due to incorrect patient position and weakness of the cardiac sphincter.
Pathogenesis of aspiration pneumonitis
The disease develops as a result of damage to the lung and bronchial tissue by hydrochloric acid contained in the stomach. Along the way, coagulative necrosis develops (which, again, is due to the action of acid on the bronchial mucosa). As a result, the secretory ability of the bronchi decreases, whichcauses them to dry out. In parallel, the acid that has penetrated the lungs causes the development of pneumonitis - aseptic inflammation of the lung tissue. The respiratory surface of the lungs decreases, the production of surfactant decreases. All this leads to an increase in the airiness of the mentioned organ (because of this, 2 forms of pathology are distinguished: asthmatic - with a predominant lesion of the bronchi, and obstructive - with damage to the lung tissue and the development of obstruction syndrome). The degree is determined by the pH of the gastric juice (the lower it is, the more concentrated the acid, and the stronger the damage). The most severe changes are observed in the alveoli.
Manifestations at the level of the alveoli
Very often, when discussing a particular disease and associated symptoms, readers are offered a photo. Diseases like pneumonitis, as a rule, do not differ in any specific external signs. But if you look at the affected tissue through a microscope (which is usually done at autopsy), you can detect certain changes.
As a result of all the above processes and under the influence of gravity, hydrochloric acid descends into the alveoli. There, due to the local effect on the alveolar tissue, the formation of an effusion (most often hemorrhagic) occurs. As a result, hemorrhagic pulmonary edema develops.
Under the influence of destruction in the alveoli, fibrin prolapse is observed, as well as the penetration of blood cells through the basement membrane (in particular, leukocytes and macrophages). As a result of the production of their enzymes, necrosis developsalveolar septa, which disrupts the structure of the lungs. In the place where the vessels are located, damage to the endothelium and the formation of microthrombi are observed. This all leads to an increase in fluid leakage through the membranes and the formation of atelectasis. Usually they are the reason why obstructive pulmonary disease develops. If pieces of undigested food or other foreign bodies enter the lungs with acid, such formation of hemorrhagic edema is combined with the development of a slow reaction of granuloma formation around the ingested body. This type of disease progresses more slowly, but is more severe.
Clinical manifestations of pathology
How can you tell if a patient has aspiration pneumonitis? A specific “disease photo” can be represented as follows:
- First of all, the clinic will be due to the direct effect of acid on the mucous membrane. There is a clinical picture of acute and severe respiratory failure - bronchospasm, increasing cyanosis, respiratory failure.
- From the side of the cardiovascular system, there is tachycardia, a drop in blood pressure. In some cases, there is a cardiac arrest or disruption of the rhythm. Along the way, cardiac output decreases and pressure in the pulmonary arteries increases. Due to the violation of gas exchange, the development of respiratory and metabolic alkalosis is observed. The more lung tissue is affected, the more severe the patient's condition and the more difficult it will be to cure.
- Usually, signs of damage and respiratory failure appear on the 2nd day, less often- later. Sometimes the symptoms may be erased, and functional impairment may not appear at all.
Diagnosis
Identification of Mendelssohn's syndrome is not an easy task, since pathology usually develops in weakened patients, and not always, as mentioned above, the clinical picture may occur. First of all, the presence of respiratory failure (dyspnea, wheezing, cyanosis) should be determined. These symptoms are not always possible to identify in patients on mechanical ventilation. The most accurate method for diagnosing Mendelssohn's syndrome is radiography, or fluorography of the lungs.
In the picture, it is possible to see the presence of effusion in the lungs, an increase in their airiness. In some cases, the contrasting of the bronchi is enhanced (normally, the bronchi are not visible on the X-ray in direct projection, and they can be identified only if lateral images are taken). If a patient undergoes a fluorography with suspicion of this syndrome, then, due to the developed necrosis, the tubular branches of the trachea will be visible on a direct radiograph.
Treatment of aspiration syndrome
If aspiration of gastric contents does occur, treatment should begin immediately. First of all, it is necessary to exclude the re-entry of acid into the lower respiratory tract. To do this (if the patient's condition allows) it is required to raise the head of his bed. Immediately it is necessary to establish ventilation in the lungs and ensure good oxygenation of the blood. As a rule, mechanical ventilation is prescribed under intermittentpositive pressure and hyperbaric blood oxygen saturation (use of ventilators, control of blood gases). All this will prevent the development of acidosis.
To reduce the volume of damage to the lung tissue, glucocorticosteroids are prescribed intravenously and a small dose of them intrabronchially. Hormones allow you to stop the spread of the process and limit it. Antibiotics (usually cephalosporins and macrolides) are prescribed for prevention. You should also take sympathomimetics (to reduce the formation of secretions in the bronchi and lungs).
Complications of the syndrome
With timely treatment, complications can usually be avoided. If late, aspiration syndrome can lead to dangerous and undesirable consequences.
Often after an illness, if it proceeded with a disruption of the rhythm, atrial fibrillation or a permanent form of ventricular fibrillation may occur in the future. If it cannot be stopped, but the patient does not complain, you can leave the patient under the supervision of a local therapist only.
Another complication is the development of lung atelectasis, or chronic obstruction. In this case, the process of stabilization of the condition will be quite long, and the emphasis, as a rule, is on the relief of symptoms, since this disease is incurable.
The most severe complication of pneumonitis is death. Especially often it occurs in cases where aspiration syndrome develops innewborns.
Prevention and prognosis of the disease
To prevent the development of aspiration pneumonia, a set of certain measures is required. First of all, all patients and women in labor who are indicated for intervention under general anesthesia should empty their stomach and intestines. This eliminates the main factor in the development of pneumonitis.
Before anesthesia, it is recommended to undergo fluorography in order to exclude the content of gastric juice in the respiratory tract. Intubation of the patient must be carried out even when the patient is conscious. The person is laid down so that the upper part of the body is slightly raised. This is achieved by adjusting the head of the bed or the operating table (this excludes the possibility of passive leakage of the contents of the digestive organs into the respiratory tract).
If the intubation technique is observed and the patient is properly prepared for surgery, the risk of developing Mendelssohn's syndrome is minimal.
Prognosis for this disease is as follows: up to 56 percent of patients who develop airway pneumonitis usually die. If treatment measures were started in a timely manner, the risk of complications and death is reduced to zero.
