Lung hyperinflation
Updates to Synonym Attributes
Updates to Synonym Attributes
Updates to Article Attributes
Lung hyperinflation is a common condition in patients with chronic obstructive pulmonary disease (COPD). It is also linked to ageing and other chronic diseases that cause airflow obstruction.
Pathology
The airflow limitation during expiration is produced by two factors:
-
destruction of the lung parenchyma
:in healthy subjects, the volume reached by the lungs after exhalation is determined by the balance of forces between the inward elastic recoil pressure of the lung and the outward recoil pressure of the chest wall.
ageing or pulmonary parenchymal destruction from other causes emphysema) result in a displacement of this point of equilibrium to a higher volume.
-
airway defects
:such as mucosal oedema, remodeling of airway mucus or impaction. In these cases, the expiratory airflow limitation is increased during exercise
The diseases that limit expiratory airflow produce lung hyperinflation. The most characteristic is chronic obstructive pulmonary disease (COPD).
Other diseases that cause an obstructive airflow pattern are
- asthma
- cystic fibrosis
- bronchiectasis
- bronchiolitis
- some interstitial diseases such as
LangerhanLangerhans cell histiocytosis- lymphangioleiomyomatosis
(LAM) - (in these two diseases in their early stages, in advanced stages show a restrictive pattern).
Radiographic features
Chest radiograph
Observable features include
-
flattened of diaphragmatic contours
considered one of themost sensitive indicators
ofof hyperinflation and interobserver variability is small.best seen in the lateral chest radiograph and consists of a loss of height of the convexity of the hemidiaphragm.
-
to measure, it is possible to draw a line connecting the sternophrenic angle and the posterior costophrenic angle.
this arch height should be greater than or equal to 2.5 cm.
it is considered clearly pathological when measures less than 1.5 cm.
minor measures correlate well with the functional importance of airflow obstruction.
-
retrosternal space measurement
a horizontal line is drawn from a point allocated 3 cm below the junction between the manubrium and sternal body, on the posterior cortex of the sternum, and the ascending aorta point. In cases of increased retrosternal space, this distance is equal or greater than 2.5 cm.
air trapping: when comparing two radiographs acquired in maximal inspiration and maximal expiration another in the vertical movement of the diaphragm is less than 3 cm.
-
ribs appearances:
more than 6 above or 10 posterior ribs in the mid-clavicular line at the lung and diaphragm level
horizontalization of ribs.
presence of air below the heart.
increased anteroposterior diameter of the chest, also called barrel chest.
hyperlucent lungs (less bronchovascular markings per cm2)
CT
Observable features include
air trapping: best seen in expiration.
-
measuring the length of the anterior union line
this is a masurement of retrosternal space more reproducible than in the chest radiograph.
-
a pathognomonic finding of chronic obstructive pulmonary disease (COPD).
it refers to decrease in the diameter of the trachea in the coronal plane and increase in the sagittal plane. It can be also seen on the chest radiograph comparing the posteroanterior and lateral projections.
-
vascular changes
an indirect sign of destruction of the lung parenchyma.
emphysema causes destruction of the lung parenchyma and pulmonary arterial hypertension.
-<p><strong>destruction of the lung parenchyma: </strong></p>- +<p><strong>destruction of the lung parenchyma</strong></p>
-<p><strong>airway defects: </strong></p>- +<p><strong>airway defects</strong></p>
-<li><a href="/articles/asthma-1"><strong>asthma</strong></a></li>-<li><a href="/articles/cystic-fibrosis"><strong>cystic fibrosis</strong></a></li>-<li><a href="/articles/bronchiectasis"><strong>bronchiectasis</strong></a></li>-<li><a href="/articles/respiratory-bronchiolitis"><strong>bronchiolitis</strong></a></li>- +<li><a href="/articles/asthma-1">asthma</a></li>
- +<li><a href="/articles/cystic-fibrosis">cystic fibrosis</a></li>
- +<li><a href="/articles/bronchiectasis">bronchiectasis</a></li>
- +<li><a href="/articles/bronchiolitis">bronchiolitis</a></li>
-<li><a href="/articles/langerhans-cell-histiocytosis"><strong>Langerhan cell histiocytosis</strong></a></li>-<li><a href="/articles/lymphangioleiomyomatosis-1"><strong>lymphangioleiomyomatosis (LAM)</strong></a></li>- +<li><a href="/articles/langerhans-cell-histiocytosis">Langerhans cell histiocytosis</a></li>
- +<li><a href="/articles/lymphangioleiomyomatosis-1">lymphangioleiomyomatosis </a></li>
-</ul><h4>Radiographic features</h4><h5><strong>Chest radiograph</strong></h5><p>Observable features include</p><ul><li>- +</ul><h4>Radiographic features</h4><h5>Chest radiograph</h5><p>Observable features include</p><ul><li>
-<li><p><strong></strong>considered one of the<strong> most sensitive indicators</strong> of hyperinflation and interobserver variability is small.</p></li>- +<li><p><strong></strong>considered one of the<strong> </strong>most sensitive indicators of hyperinflation and interobserver variability is small.</p></li>
-<p><strong><a href="/articles/retrosternal-airspace">retrosternal space</a> measurement</strong></p>- +<p><a href="/articles/retrosternal-airspace">retrosternal space</a> measurement</p>
-<li><p><strong><a href="/articles/air-trapping">air trapping</a>:</strong> when comparing two radiographs acquired in maximal inspiration and maximal expiration another in the vertical movement of the diaphragm is less than 3 cm.</p></li>- +<li><p><a href="/articles/air-trapping">air trapping</a>: when comparing two radiographs acquired in maximal inspiration and maximal expiration another in the vertical movement of the diaphragm is less than 3 cm.</p></li>
-<p><strong>ribs appearances: </strong></p>- +<p>ribs appearances:</p>
-<li><p>presence of <strong>air below the heart</strong>.</p></li>-<li><p>increased anteroposterior diameter of the chest, also called <strong>barrel chest</strong>.</p></li>-<li><p><strong>hyperlucent lungs</strong> (less bronchovascular markings per cm<sup>2</sup>)</p></li>- +<li><p>presence of air below the heart.</p></li>
- +<li><p>increased anteroposterior diameter of the chest, also called <a href="/articles/barrel-chest">barrel chest.</a></p></li>
- +<li><p>hyperlucent lungs (less bronchovascular markings per cm<sup>2</sup>)</p></li>
-<li><p><strong><a href="/articles/air-trapping">air trapping</a>:</strong> best seen in expiration.</p></li>- +<li><p><a href="/articles/air-trapping">air trapping</a><strong>:</strong> best seen in expiration.</p></li>
-<p><strong>measuring the length of the anterior union line</strong></p>- +<p>measuring the length of the anterior union line</p>
-<p><strong><a href="/articles/saber-sheath-trachea-1">Saber sheath trachea</a></strong>.</p>- +<p><a href="/articles/saber-sheath-trachea-1">Saber sheath trachea</a></p>
-<p><strong>vascular changes</strong></p>- +<p>vascular changes</p>