Decreased Breath Sounds

MANUAL OF CLINICAL DIAGNOSIS

Decreased breath sounds refer to a reduction in the intensity of respiratory noises heard through the chest. This finding can indicate a variety of pathological conditions that affect lung ventilation or the transmission of sound through the lung tissue and pleura. Identifying the underlying cause is crucial, as some of these conditions can be potentially serious and require immediate medical intervention.

Pathology	Clinical Symptoms and Signs	Suspected Diagnosis	Confirmatory Diagnosis
Decreased Respiratory Effort	Bradypnoea, hypoventilation, drowsiness, hypercapnia	Medical history, physical examination, decreased breath sounds	Arterial blood gas analysis, chest X-ray
Endobronchial Obstruction	Cough, wheezing, dyspnoea, atelectasis	Medical history, physical examination, decreased breath sounds in the affected area	Bronchoscopy, chest X-ray, chest computed tomography (CT)
Severe Asthma	Dyspnoea, wheezing, use of accessory muscles, cyanosis	History of asthma, physical examination, decreased breath sounds	Spirometry, arterial blood gas analysis
Anaphylaxis	Sudden dyspnoea, wheezing, oedema, urticaria, hypotension	History of allergen exposure, physical examination, decreased breath sounds	Allergy testing, blood tests (tryptase)
Emphysema	Progressive dyspnoea, chronic cough, decreased breath sounds, barrel chest	Smoking history, physical examination, decreased breath sounds	Chest X-ray, chest CT, spirometry
Obesity	Exertional dyspnoea, snoring, hypoventilation, decreased breath sounds	Medical history, physical examination, decreased breath sounds	Body mass index (BMI), polysomnography
Pneumothorax	Sudden chest pain, dyspnoea, decreased or absent breath sounds on the affected side	Medical history, physical examination, decreased breath sounds on the affected side	Chest X-ray, chest CT
Pleural Effusion	Dyspnoea, pleuritic chest pain, dull percussion, decreased breath sounds	Medical history, physical examination, decreased breath sounds	Chest X-ray, thoracic ultrasound, chest CT