Tracheal pathology is not particularly frequent but is fundamentally related to those pathologies that determine an obstacle to the passage of the air column as the trachea represents an organ responsible for the passage of air from the first respiratory tract to the main bronchi.
The trachea is a hollow organ, from the larynx in the cervical region passes through the upper thoracic strait to continue in the mediastinum and then divide into the two main bronchi.
The trachea, as its peculiar characteristic, has a musculo-membranous structure supported by a cartilaginous skeletal scaffolding, represented by the so-called tracheal rings in the shape of a horseshoe where continuity with the posterior wall is ensured by a musculomembranosa structure constituted by the pars membranacea. , whose function is given by the muscular structure that is able to vary the tracheal lumen due to what are the physiological needs that will occur. From the physiological point of view the trachea has the ability to modify the diameter of the airway and then adjust according to what are the laws of physics the speed of the passage of the air column and then adapt them to the physiological needs of our body, contributing to the production of a mucus, the film of mucus of which in normal conditions we produce an abundant quantity without our knowledge; if not in pathological conditions in which inflammatory phenomena (tracheitis, tracheo-bronchitis) determine an increase in the pathology of the secretion of the mucus with some modifications also in the content from the bacterial point of view. Another physiological aspect to be emphasized concerns the tracheo-bronchial epithelium, which covers the mucosa, is a ciliated epithelium, in which these eyelashes develop a unidirectional movement outwards precisely to determine a current of mucus, whose function is to pick up the particles of atmospheric dust with the help of saprophytic germs that live without expressing any pathology at the level of the tracheobronchial tree, we eliminate the outside, expanding another functional aspect of the organ.
Tracheal pathology is distinguished in congenital pathology and
acquired pathology.
Congenital disease is particularly rare; it can be treated, for example, of
atresia of the trachea (we have seen a case of an infant who was also affected
by other congenital disorders), tracheal stenosis, tracheomalacia ie the lack of
stiffness of the tracheal rings that consequently respiratory acts and during
the inhalation collapses the tracheal lumen in such a way as to create an
obstacle to the passage of the air column, chondrodysplasia and the
tracheoesophageal fistula which represents the congenital pathology par
excellence; of particular interest is also the acquired tracheal pathology,
although it is quite rare, but it is fundamentally represented by post-traumatic
pathology and neoplastic pathology.
From the nosographic point of view it is necessary to underline what are the aspects of inflammatory autoimmune pathologies or in general sense so-called idiopathic. The presence of an obstacle, a reduction of the tracheal lumen, representing an obstacle to the passage of the air column is characterized by dyspnoea, which will be characteristic, as it will affect the inspiratory phase (as opposed to the expiratory dyspnea affecting the small airways, example: asthma bronchial where a prolongation of the inhalation phase will be determined by the attempt to eliminate further lengthening the expiratory phase).
It is quite easy to notice this type of dyspnoea, not surprisingly when entering a patient's room it is immediately noticed that he suffers from such pathology because marked is the symptomatology represented by the remarkable mechanical-noisy activity- that the patient performs to bypass the difficulty restrictive tracheal for the purpose of good breathing.
Associated with the said symptoms, inspiratory dyspnea and inspiratory and expiratory stridor, there will be other completely non-specific symptoms such as cough, expectoration with alteration of the muco-ciliary clearance for which the physiological flow is altered because there will be an obstacle to the elimination of mucus; there may be the presence of hemoftoe and due to alteration of the muco-ciliary clearance infection will occur, since the stagnation of mucus represents a pabulum favorable to the germs that sometimes are present as saprophytes at the level of the tracheo-bronchial tree.
The inspiratory dyspnea and the inspiratory and expiratory stridor characteristic of the tracheal pathology, it is necessary to proceed to what is the instrumental definition of the tracheal pathology and an important contribution is provided by radiology and endoscopy because in any case to define with certainty what the cause that determines this symptom we must have an objective instrumental feedback.
From the radiological point of view the standard radiography can give important diagnostic elements; the stratigraphy represents a radiological method used around 40 years ago that exploits the capacity of the radiological tube to focus certain layers of the thorax compared to standard radiography; the tracheography, that is the half instillation of water-soluble contrast at the trachea level, is a method that is now superseded by the CT but also by the NMR.
A standard chest radiograph, anterior-posterior projection and aterolateral projection can
provide us with important information; for example, in the case of a mediastinal
flossing with a cervico-mediastinal goiter, the tracheal tape in
antero-posterior projection was not shown while in the lateroateral projection
the tracheal ribbon was to be displaced forward with reduction of the tracheal
lumen. The tracheoecography is used to establish the caliber of the trachea and
high airways and above all to highlight any narrowing, stenosis. The most modern
exams are represented by the
• Thorax CT
• MRI is a method endowed with particular sensitivity in the discernment of
tracheal pathology and the same case this lesion which is found in the passage
from the cervical trachea to the mediastinal trachea the narrowing of the
tracheal lumen.
Nevertheless, an important contribution to tracheal pathology is provided by
endoscopy which gives us the direct image of the tracheal lumen, but above all
it gives us the possibility to perform, from the diagnostic point of view, the
cytohistological samples that allow us to define the nature of endotracheal
pathology; the method is performed with a rigid or flexible bronchoscope. The
rigid bronchoscope is a diagnostic and therapeutic investigation, which is
rarely performed in patients in narcosis (total anesthesia), while flexible
bronchoscopy is performed under local anesthesia and today the collaboration
with our anesthetists is such that they provide a good sedation making the exam
more acceptable to the patient himself. Local anesthesia is instilled in the
tracheobronchial tree of a local anesthetic precisely to inhibit the cough
reflex. Once the diagnosis that is related to radiological examination, CT, MRI
and to the endoscopic examination of the trachea is defined, the treatment will
be surgical or possibly endoscopic. If the problem concerns the mediastinal
trachea, access will not be tracheostomic but thoracostomic. A good alternative
where it is not possible to carry out a surgical treatment is endoscopy.
Endoscopic therapy allows to dilate tracheal strictures, to perform a laser
treatment, to place prostheses that restore tracheal recanalization. The
dilators that we use are pneumatic dilators on which in the distal end are
present these balloons that are particularly resistant, they inflate with
physiological solution by calibrating the tracheal lumen and position themselves
under the guide directly of the endoscope. The prostheses that are used are
prostheses in silicone or metal prostheses made of a metal that has a good
memory and then introduce themselves into a kind of retina, carrying out this
retina they reach the initial position just by virtue of the memory that has the
metal that composes them. thus obtaining a good recanalization of the tracheal
shaft.
The tracheal neoplastic pathology can be classified into primary malignant, secondary malignant tumors (thyroid carcinoma that infiltrates the trachea), low malignant tumors and benign tumors. Among the primary malignant tumors we must remember from the point of view of their incidence the adenocystic carcinoma and squamous carcinoma; the adenocyst gives the real possibility that after the removal you can come across a recurrence, then there are the less frequent, to name a few there is for example the microcitome, the tracheal adenoma, the tracheal melanoma. As far as secondary malignant tumors are concerned, we have thyroid neoplasia, bronchogenic neoplasm that can spread in trachea, neoplasia of the larynx or neoplasm of the esophagus or of the tract that is in direct continuity with the trachea, infiltrating it. The low malignancy tumors the mucoepidermoid carcinoid and then we have the benign tumors that I repeat once again we can rarely find them since already the tracheal pathology itself does not turn out to be frequent. These tumors therefore originate from the different structures that characterize the cartilaginous muscle-membranous organization of the tracheobronchial tree. It is also important to know the post-traumatic pathology (this too infrequent).
Secondary neoplasms may involve the trachea through direct extension. Thyroid carcinomas typically invade the trachea at the second and third rings, where the thyroid isthmus is adherent to the trachea
Post-traumatic pathology is manifested by the stenosis, in patients subjected to long periods of endotracheal intubation, the presence of the endotracheal cannula or endotracheostomy cannula due to the decubitus can determine a inflammatory perigranulomatous region or an inflammatory stenosis of the decubitus area but the trachea can also be exposed to rupture as a result of a traumatic event. Traumatic events can be considered the iatrogenic causes, as well as the possibility that during an orotracheal intubation, in a completely accidental manner, the anesthesiologist determines the lesion trachea itself. A patient presenting with a post-traumatic tracheal pathology or however of the main symptomatic bronchi presents the cyanosis due to respiratory insufficiency but above all the subcutaneous emphysema because the laceration or the breaking of the tracheobronchial tree will cause the enlargement and the expanding air to the mediastinal tissue level. Examples of trauma may be tearing of the pars membranacea of the right main bronchus or the adventitia of the trachea may remain intact in the laceration, or there may still be a complete rupture (rarely such an episode occurs). An accidental laceration, though rare, is still possible in a person who has suffered a traffic accident; in this case a subcutaneous emphysema may appear, characteristic for addressing an alteration of the tracheobronchial tree. On the other hand, there are typical seat belt injuries, especially in overweight subjects, since the sudden deceleration causes a strangulation effect with the high axis of the laryngotracheal axis. Treatment can be conservative or surgical and is related to the patient's clinical condition. In the case of tracheobronchial laceration, suturing is the technique required to restore the continuity of the tracheal wall.
Iatrogenic injuries resulting from tracheal intubation have long been the most common lesion afflicting the airway. Postintubation injuries include granulomas, strictures, malacia, and tracheoesophageal and tracheoinnominate fistulas. The development of the large-volume, low-pressure cuff for tracheostomy and endotracheal tubes for ventilation has greatly lowered the incidence of cuff stenoses. However, overinflation of these cuffs can result in local airway damage and subsequent scar formation, and it contributes to the continued incidence of these lesions. Stenosis in the subglottic region may occur as a result of prolonged intubation with endotracheal tubes, after cricothyroidotomy, or after high placement of a tracheostomy where the tube erodes through the cricoid cartilage.
A, Cuff stenosis from the cuff of an endotracheal tube. B, Cuff stenosis from the cuff of a tracheostomy tube, usually lower in the trachea than that from an endotracheal tube. Stoma stenosis also occurs at the site of the tracheostomy itself. Malacia may occur either at the level of the cuff or in the segment between the stoma and the cuff stenosis. C, Cuff stenosis at the site of a high tracheostomy stoma, which has eroded into the lower margin of the cricoid cartilage. In older patients, this may erode back further into the subglottic larynx, producing a laryngotracheal stenosis. D, Tracheoesophageal fistula (TEF) produced by pressure of the cuff against the membranous wall, often abetted by an indwelling, firm, nasogastric tube. E, One type of tracheoinnominate fistula (TIF), the result of a high-pressure cuff erosion. The more common type, but also rare, is that seen with a low-placed tracheostomy stoma, which rests against the innominate artery itself. Not shown here are the lesions that occur in the larynx as the result of endotracheal tubes.