Atelectasis

Collected by DR Ahmad shah Samim

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 Definition
• Atelectasis is the partial or complete collapse
of a part (lobe) or the whole lung, leading to a
reduction in gas exchange.
• It can occur due to obstruction of airways or
pressure on the lung tissue, leading to
airlessness in the affected alveoli.

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 Causes
Atelectasis can be classified into two main types: obstructive and non-obstructive.
1. Obstructive causes:
- Mucus plugs: Common in postoperative patients or those with lung diseases like
asthma or COPD.
- Foreign bodies: Particularly in children.
- Tumors: Obstructing the airways.
- Bronchial stenosis: Narrowing of airways due to scarring.
2. Non-obstructive causes:
- Compression from external pressure: Pleural effusion, pneumothorax,
hemothorax, or tumors pressing on the lung.
- Surfactant deficiency: Seen in premature neonates (neonatal respiratory distress
syndrome).
- Postoperative atelectasis: Due to shallow breathing or reduced lung expansion
after surgery, especially abdominal or thoracic surgeries.
- Inadequate ventilation: In patients with neuromuscular disorders or those on
mechanical ventilation.
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- Pleural diseases: Fibrosis or scarring in the pleura can cause lung collapse.
 Pathogenesis
The pathogenesis of atelectasis depends on the cause but
involves:
- Obstructive atelectasis: Airway obstruction prevents airflow,
leading to the absorption of air in the distal alveoli, causing
them to collapse. Over time, the collapsed lung may get filled
with fluid or become fibrotic.
- Non-obstructive atelectasis: External pressure, surfactant
deficiency, or poor lung expansion can cause the alveoli to
collapse, reducing gas exchange.

The lung collapse results in hypoventilation in the affected

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 Pathologic changes
- Collapsed alveoli: Air is absorbed from the alveoli,
leading to their deflation and collapse.
- Reduced lung volume: The affected region shows
a decrease in volume.
- Potential fibrosis: Chronic atelectasis may result in
irreversible fibrosis or scarring of the lung tissue.
- Air trapping and infection: In obstructive
atelectasis, retained secretions can become
infected, leading to pneumonia or abscess
formation.
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 Diagnosis
1. Clinical examination:
- Dullness on percussion and decreased breath sounds over the affected
area.
- Tracheal deviation toward the affected side (in severe cases).
- Reduced chest wall movement on the affected side.

2. Imaging:
- Chest X-ray: Shows opacification of the collapsed lung or segment,
displacement of fissures, or mediastinal shift toward the collapsed lung.
- CT scan: More sensitive than X-ray for detecting small areas of atelectasis
or the cause of obstruction.
- Bronchoscopy: Useful in visualizing and potentially removing airway
obstructions, such as foreign bodies or tumors.

3. Laboratory tests:
- Not diagnostic but can help rule out infection (pneumonia) if fever and
elevated white blood cells are present.
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 Differential diagnosis:
- Pneumonia: Can present similarly with fever,
cough, and opacification on chest X-ray.
- Pleural effusion: Fluid collection in the pleura may
mimic atelectasis on imaging.
- Pneumothorax: Air in the pleural space can also
cause lung collapse but will show a different pattern
on imaging.
- Pulmonary embolism: Can cause localized areas
of lung infarction or collapse.
- Lung tumors: Can present with localized lung
collapse if obstructing airways.
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 Prevention
1. Postoperative care:
- Early ambulation and deep breathing exercises to
encourage full lung expansion.
- Incentive spirometry: To help expand the lungs post-
surgery.
- Proper pain control: To facilitate deep breathing and
coughing.

2. Chest physiotherapy: Includes postural drainage, chest

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 Treatment
1. Supportive care:
- Oxygen therapy: If hypoxia is present.
- Chest physiotherapy: Includes postural drainage and percussion to
mobilize secretions.
- Incentive spirometry: To encourage lung expansion.
2. Medications:
- Bronchodilators: To open airways, especially in patients with asthma or
COPD.
- Mucolytics: Such as acetylcysteine to break down mucus and reduce
obstruction.
3. Surgical or procedural interventions:
- Bronchoscopy: To remove foreign bodies, tumors, or mucus plugs causing
obstruction.
- Thoracentesis: To drain pleural effusion if it’s causing lung compression.
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- Chest tube insertion: For pneumothorax or large pleural effusions.
 Treatment
1. Bronchodilators (e.g., albuterol):
- Dosage: 2.5 mg nebulized or 90 mcg via inhaler every 4–6 hours.
- Duration: Until symptoms improve, typically several days to a week in acute
settings.
2. Mucolytics (e.g., acetylcysteine):
- Dosage: 10% or 20% solution via nebulizer, 3–5 mL every 6–8 hours.
- Duration: Until mucus clearance improves, usually over a few days to a week.
3. Antibiotics:
- If infection (such as pneumonia) is suspected or confirmed, antibiotics may be used
based on the underlying pathogen.
- Common antibiotics include amoxicillin/clavulanate, ceftriaxone, or azithromycin.
- Duration: Typically 7–14 days, depending on the severity of infection.
4. Postoperative incentive spirometry:
- Dosage: 10 deep breaths every hour while awake.
- Duration: Continued until full recovery or lung expansion is achieved post-surgery.
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