Pneumothorax, atelectasis and bronchiectasis
Terms in this set (27)
Separation of visceral and parietal pleurae by a volume of air
What does pneumothorax cause?
Collapse of affected lung secondary to surface tension induced recoil of its collective alveoli (small section all the way to entire lung collapse)
Describe the 4 major categories of pneumothorax
1) primary spontaneous PTX: occurs in the absence of an underlying disease. Thought due to rupture of sub pleural apical blend due to high negative intrapleural pressure
2) secondary spontaneous PTX: occurs as a complication of lung disease
3) traumatic PTX: secondary to blunt or penetrating trauma ; iatrogenic causes (subclavian or internal jugular vein cath, Thoracentesis, percutaneous lung biopsy, pleural biopsy, pulmonary barotrauma from mechanical over ventilation)
4) tension PTX: air enters the thorax through a hole in the chest wall during inspiration but does not exit during expiration. Positive inter pleural pressure is greater than ambient pressure. May be secondary to trauma, CPR or mechanical ventilation.
Lung diseases associated with secondary PTX
Catamenial PTX- associated with onset of menses +/- 3 days also intrathoracic endometriosis
Symptoms of any pneumothorax
Ipsilateral chest pain
If PTX< 15% of hemithorax= possibly only mild tachycardia
If PTX Is large: breath sounds and fremitus decrease, asymmetric chest expansion, hyperressonance or tympany on chest percussion
Objective findings of pneumothorax
Mild cases- minimal findings
Severe cases- unilateral chest expansion; tracheal and mediastinal shift toward side opposite the PTX (in tension PTX); percussion hyperressonance or tympany; CXR shows visceral pleural line and/or area of thorax with absent pulmonary vasculature.
Risk factors of primary PTX
Often in tall thin young men (10-30yo)
Increased risk with smoking
Important common cause of traumatic PTX
Pulmonary barotrauma in pts on mechanical ventilation. Often seen in pts with ARDS
Signs and symptoms that indicate tension PTX
Severe dyspnea and tachycardia
Tracheal and mediastinal shift
Systemic hypotension due to decreased venous return
Widespread percussion hyperressonance or tympany
Labs for a PTX
ABGs show hypoxemia; acute respiratory alkalosis from hyperventilation
CXR: visceral pleural line is a definitive diagnosis; may see pleural effusion; may see shift of tracheal air column toward NL PTX or away from a tension PTX
Differential diagnosis of PTX
Treatment of PTX
Depends on severity.
1) small PTX <15% hemithorax: may only observe as often resolves;
O2 supplementation may increase rate of air reabsorption;
Aspiration with angiocath OR
Serial CXRs every 24hrs to follow progress.
Large or tension PTX: admission to hospital.
Thoracostomy until lung expands on serial CXRs
Counseling for PTX
Stop smoking (50% recurrence)
Avoid high altitude, scuba diving, unpressurized aircrafts.
Average recurrence after spontaneous PTX: 30%
Collapse of the alveoli
Describe the difference between pneumothorax and atelectasis
Both involve collapse of the alveoli.
Pneumothorax is caused by separation of the visceral an parietal pleura.
Atelectasis can be caused by a number of mechanisms but IS NOT DUE to separation of membranes
4 categories of atelectasis
Diffuse micro atelectasis
Describe resorption atelectasis
Obstruction in the airway prevents ventilation. Existing air in the alveoli gets absorbed and alveoli collapse.
Can cause collapse of one or more segments or entire lung.
Typical obstruction: bronchus obstruction by mucus plug (ex after surgery); foreign body;
Tumor; enlarged lymph nodes (ex TB)
Describe compression atelectasis (aka passive or relaxation)
Most commonly caused by something pushing the lung tissue out of the way or otherwise occupies space where the lung normally resides.
Common causes: pleural effusion; tumor; emphysematous bullae; cardiomegaly; elevated position of diaphragm in bedridden patients or those with ascites
Describe contraction atelectasis (aka cicatrization)
Caused by local or generalized fibrosis in lung or pleura
Describe diffuse micro atelectasis
Generalized loss of lung expansion due to inadequate surfactant.
Caused by O2 toxicity; neonatal or adult respiratory distress syndrome; infection
Signs and symptoms of atelectasis
Uneven chest expansion
Locally decreased breath sounds
DULLNESS to percussion
CXR: opaque lung section
AT of the lower love may cause upwardly domed hemidiaphragm. AT of upper lobe or entire lung may cause tracheal air shift or mainstream bronchi to deviate TOWARD the opacity
Prophylactic measures against atelectasis
After surgery: encourage ventilation by incentive spirometer, coughing, early annular ion.
Use narcotic sparingly as they inhibit cough reflex.
Turn patient hourly in bed.
Treatment for atelectasis
Respiratory therapy with vibropercussion.
Position recumbent patient with affected lung uppermost to encourage drainage.
Fiber optic bronchoscopy to remove mucus plug of FB.
Antibiotics for infection
Pathological expansion of bronchi or bronchioles resulting from necrotizing infections that destroy bronchial smooth muscle and elastic tissue. Therefore it is not a primary disease
Signs and symptoms of bronchiectasis
Expectoration of copious purulent sometimes fetid sputum.
Flecks of blood in sputum if not frank hemoptysis.
Conditions that increase the risk of bronchiectasis
Bronchial obstruction caused by tumors, foreign body or mucus impaction Leading to infection an bronchiectasis localized to the obstructed segment.
Cystic fibrosis: autosomal recessive inherited condition that affects the lungs and pancreas (in some). Results in vey thick mucus and inability to clear pathogens from lungs. Test results show high sweat chloride results.
HIV or immunodeficiency leading to recurrent infections and bronchiectasis.
Pneumonia that is incompletely resolved.
Pathogenesis of bronchiectasis
Two critical factors:
Obstruction and chronic recurrent infection. Either one can occur first and cause the second.
Typically affects the lower lobes especially the most vertical airways.
Affected airways dilate to 4x normal diameter. Gross dissection can trace severely dilated bronchioles almost to the pleura.