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ULY CLINIC
ULY CLINIC
25 Mei 2025, 10:15:09
Asymmetrical chest expansion
Definition and pathophysiology
Asymmetrical chest expansion refers to the uneven movement or extension of the thoracic cage during inspiration. Under normal physiological conditions, the thorax expands symmetrically in an upward and outward direction during inspiration and recoils inward and downward during expiration. This coordinated motion facilitates optimal lung inflation and ventilation. When disrupted, the chest wall exhibits uncoordinated or diminished expansion on one or both sides, reflecting underlying pathology that impairs lung or chest wall mechanics.
Asymmetry may manifest suddenly or develop insidiously, presenting as unilateral lagging of chest movement (chest lag), paradoxical motion, intercostal retractions, or complete absence of expansion on one side. The condition increases the work of breathing and may result in rapid, shallow, or inefficient respirations, compromising gas exchange and respiratory function.
Etiology
Comprehensive table of medical causes of asymmetrical chest expansion, including brief key features to help identify each cause:
Cause | Pathophysiology / Description | Key Clinical Features |
Bronchial Obstruction | Partial or complete airway blockage causing decreased ventilation on one side. | Decreased/absent breath sounds, chest lag, intercostal bulging on expiration, dyspnea, accessory muscle use. |
Flail Chest | Multiple rib fractures causing a segment of chest wall to move paradoxically. | Paradoxical chest wall movement, ecchymoses, severe localized pain, tachypnea, cyanosis, rapid shallow breathing. |
Hemothorax | Bleeding into pleural space compressing lung and restricting expansion. | Chest lag, dullness on percussion, tachycardia, hypotension (shock), stabbing chest pain, hypoxemia. |
Kyphoscoliosis | Abnormal spine curvature compresses one lung, limits chest expansion. | Unequal chest expansion, ineffective cough, dyspnea, fatigue, back pain. |
Myasthenia Gravis | Neuromuscular weakness affects respiratory muscles causing asynchronous chest and abdominal movement. | Shallow respirations, abdominal paradox, progressive dyspnea, tachypnea, risk of respiratory failure. |
Pleural Effusion | Fluid accumulation in pleural space restricts lung expansion. | Chest lag, dullness on percussion, decreased breath sounds, egophony, pleuritic chest pain, fever (if infected). |
Pneumonia | Lung consolidation reduces lung compliance and movement, usually unilateral. | Fever, tachypnea, crackles, chest pain worsening on inspiration, productive cough, asymmetric chest expansion. |
Pneumothorax | Air in pleural space causes lung collapse, impairs chest wall movement. | Sudden stabbing chest pain, decreased breath sounds, hyperresonance, tachypnea, mediastinal shift (tension type). |
Pulmonary Embolism | Obstruction of pulmonary artery causing ventilation-perfusion mismatch and impaired lung expansion. | Sudden chest pain, dyspnea, tachycardia, pleural friction rub, anxiety, hemoptysis. |
Post-Pneumonectomy | Surgical removal of a lung causes asymmetry due to absent lung expansion on one side. | Absent chest movement on operated side, reduced breath sounds, possible mediastinal shift. |
Surgical Rib Resection | Removal of ribs decreases chest wall stability and expansion on affected side. | Localized chest lag, pain, decreased chest movement on side of rib removal. |
Mainstem Bronchus Intubation | Endotracheal tube inserted too far causes ventilation of only one lung. | Absent breath sounds on non-ventilated side, hypoxia, chest asymmetry. |
Chest Wall Trauma (Other) | Fractures, contusions, or muscle injuries restrict movement of one side. | Localized pain, swelling, bruising, decreased chest expansion on affected side. |
Unilateral Diaphragm Paralysis | Phrenic nerve injury or neuromuscular disease causes diaphragmatic dysfunction on one side. | Paradoxical abdominal movement, decreased chest expansion on affected side, dyspnea, orthopnea. |
Lung Collapse (Atelectasis) | Partial or complete lung collapse decreases expansion on affected side. | Decreased breath sounds, dullness on percussion, dyspnea, chest lag. |
Large Pulmonary Mass or Tumor | Mass effect limits lung expansion unilaterally. | Chest asymmetry, decreased breath sounds, possible localized pain, cough. |
Chest Wall Deformities | Congenital or acquired deformities like pectus excavatum or Poland syndrome affect chest expansion symmetry. | Visible chest wall deformity, asymmetric movement, possible respiratory difficulty. |
Clinical assessment
History
A thorough history is critical to elucidate the underlying cause. Key questions include:
Onset and progression of symptoms (acute vs. chronic).
Presence of dyspnea: constant or episodic; worsened by activity, coughing, or position changes.
Associated pain: character, location, aggravating and relieving factors, and its relation to respiratory phases.
Past medical history including pulmonary infections, chronic respiratory diseases (e.g., asthma, tuberculosis), malignancies, or previous thoracic surgeries.
History of trauma, occupational exposures to inhaled toxins, or recent intubation.
Physical examination
Inspection and Palpation:Assess tracheal position for midline deviation, a potential sign of tension pneumothorax or large pleural effusion. Palpate for tenderness, deformities, or subcutaneous emphysema.
Chest Expansion Measurement:Place thumbs along the lower posterior chest wall at the 10th ribs with fingers encircling the lateral ribs. Observe the degree and symmetry of thumb separation during deep inspiration. Repeat on the upper posterior and anterior chest walls for comprehensive evaluation.
Tactile Fremitus:Use the ulnar surface of the hand to assess vibrations transmitted through the lung parenchyma while the patient repeats “99.” Increased fremitus suggests lung consolidation, while decreased or absent fremitus indicates air or fluid in the pleural space or obstruction.
Percussion:Identify areas of dullness (pleural effusion, consolidation) or hyperresonance (pneumothorax, emphysema).
Auscultation:Listen for breath sounds—normal vesicular, decreased, or absent sounds. Note adventitious sounds such as crackles, wheezes, bronchial breath sounds, egophony, bronchophony, or whispered pectoriloquy.
Emergency management
Prompt recognition of asymmetrical chest expansion is essential, particularly when it signals life-threatening conditions:
Flail Chest:Stabilize the flail segment temporarily with adhesive tape or sandbags to reduce paradoxical motion. Assess airway, breathing, and circulation (ABCs). Provide supplemental oxygen via appropriate delivery device. Initiate intravenous access for fluids, analgesics, and emergency medications. Monitor with cardiac telemetry and prepare for possible mechanical ventilation. Arterial blood gases guide oxygenation and ventilation status.
Tension Pneumothorax:Requires immediate decompression via needle thoracostomy followed by chest tube placement. Recognize signs such as severe respiratory distress, tracheal deviation away from the affected side, hypotension, jugular venous distention, and cyanosis.
Hemothorax:Control bleeding, oxygen supplementation, volume resuscitation, and urgent chest tube drainage are critical. Monitor hemodynamic status vigilantly.
Diagnostic workup
Chest X-ray: Identifies pneumothorax, hemothorax, pleural effusion, lung consolidation, and rib fractures.
Ultrasound: Useful at bedside for rapid detection of pleural fluid or pneumothorax.
CT Scan: Provides detailed evaluation of thoracic anatomy, trauma extent, and pulmonary pathology.
Arterial Blood Gas: Evaluates oxygenation, ventilation, and acid-base balance.
Pulmonary Function Tests: May aid in chronic causes like kyphoscoliosis or neuromuscular disorders.
Special populations
Pediatric considerations
Children’s small thoracic cages may cause breath sounds to be transmitted across lungs, complicating auscultation. They are prone to left mainstem bronchus intubation due to airway anatomy, necessitating careful monitoring of chest expansion during ventilation. Congenital abnormalities like diaphragmatic hernia or cerebral palsy may cause asymmetrical expansion with associated clinical features.
Geriatric considerations
Age-related thoracic deformities and decreased chest wall compliance can mask or complicate assessment. Careful interpretation of asymmetry and additional imaging may be necessary.
Patient education and counseling
Educate patients and caregivers about recognizing early symptoms of respiratory distress, including increased work of breathing, persistent dyspnea, and cyanosis. Teach effective coughing and deep breathing exercises to promote lung expansion and reduce atelectasis. Emphasize the importance of prompt medical evaluation if symptoms worsen.
References
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Light RW. Pleural Diseases. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2013.
Broaddus VC, Mason RJ, Ernst JD, et al. Murray & Nadel's Textbook of Respiratory Medicine. 6th ed. Philadelphia, PA: Elsevier Saunders; 2016.
Marik PE. Flail chest and pulmonary contusion. Crit Care Med. 2004;32(11 Suppl):S390–S395.