Atelectasis
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Atelectasis | |
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Other names | Collapsed lung[1] |
Atelectasis of a person's right lung | |
Pronunciation | |
Specialty | Pulmonology |
Atelectasis is the partial collapse or closure of a lung resulting in reduced or absent gas exchange. It is usually unilateral, affecting part or all of one lung.[2] It is a condition where the alveoli are deflated down to little or no volume, as distinct from pulmonary consolidation, in which they are filled with liquid. It is often referred to informally as a collapsed lung, although more accurately it usually involves only a partial collapse, and that ambiguous term is also informally used for a fully collapsed lung caused by a pneumothorax.[1]
It is a very common finding in
The term uses combining forms of atel- + ectasis, from Greek: ἀτελής, "incomplete" + ἔκτασις, "extension".
Signs and symptoms
May have no signs and symptoms or they may include:[3]
- cough, but not prominent;
- chest pain (not common);
- breathing difficulty(fast and shallow);
- low oxygen saturation;
- pleural effusion (transudate type);
- cyanosis (late sign);
- increased heart rate.
It is a common misconception and pure speculation that atelectasis causes fever. A study of 100 post-op patients followed with serial chest X-rays and temperature measurements showed that the incidence of fever decreased as the incidence of atelectasis increased.[4] A recent review article summarizing the available published evidence on the association between atelectasis and post-op fever concluded that there is no clinical evidence supporting this speculation.[5]
Causes
The most common cause is post-surgical atelectasis, characterized by splinting, i.e. restricted breathing after abdominal surgery. Atelectasis develops in 75–90% of people undergoing general anesthesia for a surgical procedure.[6]
Another common cause is pulmonary
Risk factors associated with increased likelihood of the development of atelectasis include: type of surgery (thoracic, cardiopulmonary surgeries), use of muscle relaxation, obesity, high oxygen, the lower lung segments.
Factors also associated with the development of atelectasis include: age, presence of chronic obstructive pulmonary disease or asthma, and type of anesthetic.
In the early 1950s, in UK aviation medicine, the condition acceleration atelectasis was given the name "Hunter lung" due to its prevalence in pilots of the transonic fighter jet, the Hawker Hunter, which used a 100% oxygen supply.[8][9]
Diagnosis
Clinically significant atelectasis is generally visible on chest X-ray; findings can include lung opacification and/or loss of lung volume. Post-surgical atelectasis will be bibasal in pattern. Chest
Classification
Atelectasis may be an acute or chronic condition. In acute atelectasis, the lung has recently collapsed and is primarily notable only for airlessness. In chronic atelectasis, the affected area is often characterized by a complex mixture of airlessness, infection, widening of the bronchi (bronchiectasis), destruction, and scarring (fibrosis).
Absorption (resorption) atelectasis
The
Compression (relaxation) atelectasis
It is usually associated with accumulation of blood, fluid, or air within the pleural cavity, which mechanically collapses the lung. This is a frequent occurrence with pleural effusion, caused by congestive heart failure (CHF). Leakage of air into the pleural cavity (pneumothorax) also leads to compression atelectasis.[12]
Cicatrization (contraction) atelectasis
It occurs when either local or generalized fibrotic changes in the lung or
Chronic atelectasis
Chronic atelectasis may take one of two forms—middle lobe syndrome or rounded atelectasis.
Right middle lobe syndrome
In right middle lobe syndrome, the middle lobe of the right lung contracts, usually because of pressure on the bronchus from enlarged
Patchy atelectasis
Is due to lack of surfactant, as occurs in hyaline membrane disease of newborn or acute (adult) respiratory distress syndrome (ARDS).[14]
Rounded atelectasis
In rounded atelectasis (folded lung or Blesovsky syndrome[15]), an outer portion of the lung slowly collapses as a result of scarring and shrinkage of the membrane layers covering the lungs (pleura), which would show as visceral pleural thickening and entrapment of lung tissue. This produces a rounded appearance on X-ray that doctors may mistake for a tumor. Rounded atelectasis is usually a complication of asbestos-induced disease of the pleura, but it may also result from other types of chronic scarring and thickening of the pleura.
Treatment
Treatment is directed at correcting the underlying cause. In atelectasis manifestations that result from the mucus plugging of the airways as seen in patients with cystic fibrosis and pneumonia, mucolytic agents such as acetylcysteine (NAC) is used. This nebulized treatment works by reducing mucous viscosity and elasticity by breaking disulfide bonds in mucoproteins within the mucus complex, thus facilitating mucus clearance.
The primary treatment for acute massive atelectasis is correction of the underlying cause. A blockage that cannot be removed by coughing or by suctioning the airways often can be removed by bronchoscopy.
See also
- Alveolar capillary dysplasia, a very rare type of diffuse congenital disorder of the lung
- Flat-chested kitten syndrome or FCKS: atelectasis in neo-natal kittens
- ear drum into the middle earcan also be referred to as atelectasis.
- William Pasteur, pioneer pulmonologist
References
- ^ ISBN 9780781741521.
- ISBN 0-8036-1289-3.[page needed]
- ^ "Atelectasis". MayoClinic. Retrieved 20 February 2017.
- PMID 7813318.
- PMID 21527508.
- ISBN 9780702062940.
- ^ Tarun Madappa (November 28, 2017). "Atelectasis". Medscape. Retrieved 2018-02-02.
- ISSN 1361-4231.
- ^ Lt Col Rob "Mongo" Monberg. "Review of acceleration atelectasis: An old problem in new settings" (PDF). IAMFSP.
- ^ Woodring, John H., and James C. Reed. "Types and mechanisms of pulmonary atelectasis." Journal of thoracic imaging 11.2 (1996): 92-108.
- ^
White, Gary C. (2002). Basic Clinical Lab Competencies for Respiratory Care, 4th ed. Delmar Cengage Learning. p. 230. ISBN 978-0-7668-2532-1.
- ^ ISBN 978-1-4377-1781-5.
- ^ Sheikh, Zishan; Weerakkody, Yuranga. "Lung atelectasis". Radiopaedia. Retrieved 20 February 2017.
- ^ Kaplan medical pathology lecture notes book (2019). p.118
- PMID 7268670.
- PMID 31424900.