Some Causes of Acute* Dyspnea
Cause | Suggestive Findings | Diagnostic Approach† |
|---|---|---|
Pulmonary causes | ||
Asthma, bronchospasm, or reactive airway disease | Wheezing and poor air exchange that arise spontaneously or after exposure to specific stimuli (eg, allergen, URI, cold, exercise) Possibly pulsus paradoxus Often a preexisting history of reactive airway disease | Clinical evaluation Sometimes pulmonary function testing or peak flow measurement |
Sudden onset of cough or stridor in a patient (typically an infant or young child) without URI or constitutional symptoms | Inspiratory and expiratory chest x-rays Sometimes bronchoscopy | |
Abrupt onset of sharp chest pain, tachypnea, diminished breath sounds, and hyperresonance to percussion May follow injury or occur spontaneously (especially in tall, thin patients and in patients with COPD) | Chest x-ray | |
Abrupt onset of sharp chest pain, tachypnea, and tachycardia Often risk factors for pulmonary embolism (eg, cancer, immobilization, DVT, pregnancy, use of oral contraceptives or other estrogen-containing drugs, recent surgery or hospitalization, family history) | CT angiography Less often, V/Q scanning and possibly pulmonary arteriography | |
Toxin-induced airway damage (eg, due to inhalation of chlorine or hydrogen sulfide) | Sudden onset after occupational exposure or inappropriate use of cleaning agents | Inhalation usually obvious by history Chest x-ray Sometimes ABG measurement and observation to determine severity |
Cardiac causes | ||
Substernal chest pressure or pain that may or may not radiate to the arm or jaw, particularly in patients with risk factors for CAD | ECG Cardiac enzyme testing | |
Papillary muscle dysfunction or rupture | Sudden onset of chest pain, new or loud holosystolic murmur, and signs of heart failure, particularly in patients with recent MI | Auscultation Echocardiography |
Other causes | ||
Anxiety disorder causing hyperventilation | Situational dyspnea often accompanied by psychomotor agitation and paresthesias in the fingers or around the mouth Normal examination findings and pulse oximetry measurements | Clinical evaluation Diagnosis of exclusion |
Acute diaphragmatic paralysis | Often sudden onset after trauma affecting the phrenic nerve‡ Frequent orthopnea | Chest x-ray Fluoroscopic sniff test |
* Acute dyspnea occurs within minutes of triggering event. | ||
† Most patients should have pulse oximetry and, unless symptoms are clearly a mild exacerbation of known chronic disease, chest x-ray. | ||
‡ Dyspnea may be delayed and may occur mainly after exertion. | ||
ABG = arterial blood gas; BNP = brain (B-type) natriuretic peptide; CAD = coronary artery disease; COPD = chronic obstructive pulmonary disease; DVT = deep venous thrombosis; ECG = electrocardiography; MI = myocardial infarction; S3 = third heart sound; URI = upper respiratory infection; V/Q = ventilation/perfusion. | ||