Professional Guide to Signs and Symptoms
5th Edition

Typically a symptom of cardiopulmonary dysfunction, dyspnea is the sensation of difficult or uncomfortable breathing. It’s usually described as shortness of breath. Its severity varies greatly and is usually


unrelated to the severity of the underlying cause. Dyspnea may arise suddenly or slowly and may subside rapidly or persist for years.
Most people normally experience dyspnea when they exert themselves, and its severity depends on their physical condition. In a healthy person, dyspnea is quickly relieved by rest. Pathologic causes of dyspnea include pulmonary, cardiac, neuromuscular, and allergic disorders. It may also be caused by anxiety. (See Dyspnea: Causes and associated findings.)
If a patient complains of shortness of breath, quickly look for signs of respiratory distress, such as tachypnea, cyanosis, restlessness, and accessory muscle use. Prepare to administer oxygen by nasal cannula, mask, or endotracheal tube. Ensure patent I.V. access, and begin cardiac monitoring and oxygen saturation monitoring to detect arrhythmias and low oxygen saturation, respectively. Expect to insert a chest tube for severe pneumothorax and to administer continuous positive airway pressure (CPAP).
If the patient can answer questions without increasing his distress, take a complete history. (See Differential diagnosis: Dyspnea, pages 276 and 277.) Ask if the shortness of breath began suddenly or gradually. Is it constant or intermittent? Does it occur during activity or while at rest? If the patient has had dyspneic attacks before, ask if they’re increasing in severity. Can he identify what aggravates or alleviates these attacks? Does he have a productive or nonproductive cough or chest pain? Ask about recent trauma, and note a history of upper respiratory tract infection, deep vein phlebitis, or other disorders. Ask the patient if he smokes or is exposed to toxic fumes or irritants on the job. Find out if he also has orthopnea, paroxysmal nocturnal dyspnea, or progressive fatigue.
During the physical examination, look for signs of chronic dyspnea such as accessory muscle hypertrophy (especially in the shoulders and neck). Also look for pursed-lip exhalation, clubbing, peripheral edema, barrel chest, diaphoresis, and jugular vein distention.
Check blood pressure and auscultate the lungs for crackles, abnormal heart sounds or rhythms, egophony, bronchophony, and whispered pectoriloquy. Finally, palpate the abdomen for hepatomegaly, and assess the patient for edema.

  • Acute respiratory distress syndrome (ARDS). This life-threatening form of noncardiogenic pulmonary edema usually produces acute dyspnea as the first complaint. As respiratory distress progresses, the patient develops restlessness, anxiety, decreased mental acuity, tachycardia, and crackles and rhonchi in both lung fields. Other findings include cyanosis, tachypnea, motor dysfunction, and intercostal and suprasternal retractions. Severe ARDS can produce signs of shock, such as hypotension and cool, clammy skin.
  • Amyotrophic lateral sclerosis. Also known as Lou Gehrig’s disease, this disorder causes slow onset of dyspnea that worsens with time. Other features include dysphagia, dysarthria, muscle weakness and atrophy, fasciculations, shallow respirations, tachypnea, and emotional lability.
  • Anemia. Dyspnea usually develops gradually in anemia, which commonly causes fatigue, weakness, and syncope; severe anemia may also cause tachycardia, tachypnea, restlessness, anxiety, and thirst.
  • Anthrax, inhalation. Anthrax is an acute infectious disease that’s caused by the gram-positive, spore-forming bacterium Bacillus anthracis, Although the disease most commonly occurs in wild and domestic grazing animals, such as cattle, sheep, and goats, the spores can live in the soil for many years. The disease can occur in humans exposed to infected animals, tissue from infected animals, or biological agents. Most natural cases occur in agricultural regions worldwide. Anthrax may occur in cutaneous, inhalation, or GI forms.
    Inhalation anthrax is caused by inhalation of aerosolized spores. The disease generally occurs in two stages with a period of recovery after the initial signs and symptoms. Dyspnea is a symptom of the second stage of this disorder along with fever, stridor and hypotension; the patient usually dies within 24 hours. Initial signs and symptoms are flulike and include fever, chills, weakness, cough, and chest pain.
  • Aspiration of a foreign body. Acute dyspnea marks this life-threatening condition, along with paroxysmal intercostal, suprasternal, and substernal retractions. The patient may also display accessory muscle use, inspiratory stridor, tachypnea, decreased or absent breath sounds, asymmetrical chest expansion, anxiety, cyanosis, diaphoresis, and hypotension.



  • Asthma. Acute dyspneic attacks occur in this chronic disorder along with audible wheezing, a dry cough, accessory muscle use, nasal flaring, intercostal and supraclavicular retractions, tachypnea, tachycardia, diaphoresis, prolonged expiration, flushing or cyanosis, and apprehension. Medications that block beta receptors can exacerbate asthma attacks.
  • Avian influenza. These potentially life-threatening viruses are spread to humans through contact with infected poultry or surfaces contaminated with infected bird excretions. Within 1 to 5 days of exposure to avian influenza, the patient typically develops flulike symptoms, such as fever, sore throat, cough, and muscle aches. Those with severe forms of the virus may develop dyspnea caused by acute respiratory distress or pneumonia. To date, the most virulent strain of this virus has not yet surfaced in humans in the United States, but a recent outbreak in Asian countries has had a mortality rate of about 50% among infected humans.
  • Blast lung injury. The result of a forceful percussive wave following an explosive detonation, blast lung injury is commonly characterized by dyspnea and hypoxia. Worldwide terrorist activity has recently increased the incidence of this condition, which may also cause cyanosis, chest pain, wheezing, and hemopytsis. Chest X-ray, the primary diagnostic tool, reveals a characteristic “butterfly” pattern. Many of these patients suffer concomitant injuries and require complex management, usually in an intensive care setting.
  • Cardiac arrhythmias. Acute or gradual dyspnea can result from decreased cardiac output in a patient with arrhythmias. The pulse rate may be rapid, slow, or irregular, with frequent premature or escape beats. Alternating pulse may be present. Other symptoms include palpitations, chest pain, diaphoresis, light-headedness, weakness, and vertigo.
  • Cor pulmonale. Chronic dyspnea begins gradually with exertion and progressively worsens until it occurs even at rest. Most patients with cor pulmonale have an underlying cardiac or pulmonary disease. Other findings may include a chronic productive cough, wheezing, tachypnea, jugular vein distention, dependent edema, hepatomegaly, increasing fatigue, weakness, and light-headedness.
  • Emphysema. This chronic disorder gradually causes progressive exertional dyspnea as well as barrel chest, accessory muscle hypertrophy, diminished breath sounds, anorexia, weight loss, malaise, peripheral cyanosis, tachypnea, pursed-lip breathing, prolonged expiration and, possibly, a chronic productive cough. Clubbing is a late sign. The patient may have a history of smoking, an alpha1-antitrypsin deficiency, or exposure to an occupational irritant.
  • Flail chest. In this condition, dyspnea results suddenly from multiple rib fractures and is accompanied by paradoxical chest movement, severe chest pain, hypotension, tachypnea, tachycardia, and cyanosis. Bruising and decreased or absent breath sounds occur over the affected side.
  • Guillain-Barré syndrome. This syndrome, which usually follows a fever and upper respiratory tract infection, causes slowly worsening dyspnea along with fatigue, ascending muscle weakness and, eventually, paralysis.
  • Heart failure. Dyspnea usually develops gradually in patients with heart failure. Chronic paroxysmal nocturnal dyspnea, orthopnea, tachypnea, tachycardia, palpitations, ventricular gallop, fatigue, dependent peripheral edema, hepatomegaly, dry cough, weight gain, and loss of mental acuity may occur. With acute onset, heart failure may produce jugular vein distention, bibasilar crackles, oliguria, and hypotension.
  • Interstitial fibrosis. Besides dyspnea, this disorder causes chest pain, a dry cough, crackles, weight loss and, possibly, cyanosis and pleural friction rub.
  • Lung cancer. Dyspnea develops slowly and worsens progressively in late-stage lung cancer. Other findings include fever, hemoptysis, a productive cough, wheezing, clubbing, chest pain, and pleural friction rub.

  • Monkeypox. Dyspnea is one of the less common symptoms of this rare viral disease. Infected individuals may also experience fever, muscle aches, sore throat, chills, and lymphadenopathy. A papular rash appears 1 to 3 days after the fever begins. The virus is similar to smallpox; however, the symptoms are milder and the disease is rarely fatal in developed countries.
  • Myasthenia gravis. This neuromuscular disorder causes bouts of dyspnea as the respiratory muscles weaken. In myasthenic crisis, acute respiratory distress may occur, with shallow respirations and tachypnea.
  • Myocardial infarction. Sudden dyspnea occurs with crushing substernal chest pain that may radiate to the back, neck, jaw, and arms. Other signs and symptoms include nausea, vomiting, diaphoresis, vertigo, hypertension or hypotension, tachycardia, anxiety, and pale, cool, clammy skin.
  • Plague. Caused by Yersinia pestis, plague is one of the most virulent and, if untreated, most lethal bacterial infections known. Clinical forms include bubonic (the most common), septicemic, and pneumonic plagues. The pneumonic form can be contracted by inhaling respiratory droplets from an infected person or inhaling the organism that has been dispersed in the air through biological warfare. Among the symptoms of the pneumonic form are dyspnea, a productive cough, chest pain, tachypnea, hemoptysis, increasing respiratory distress, and cardiopulmonary insufficiency.
  • Pleural effusion. Dyspnea develops slowly and worsens progressively in this disorder. Initial findings include a pleural friction rub accompanied by pleuritic pain that worsens with coughing or deep breathing. Other findings include a dry cough; dullness on percussion; egophony, bronchophony, and whispered pectoriloquy; tachycardia; tachypnea; weight loss; and decreased breath sounds, chest motion, and tactile fremitus. Fever may occur if infection is present.
  • Pneumonia. Dyspnea occurs suddenly in pneumonia and is usually accompanied by fever, shaking chills, pleuritic chest pain that worsens with deep inspiration, and a productive cough. Fatigue, headache, myalgia, anorexia, abdominal pain, crackles, rhonchi, tachycardia, tachypnea, cyanosis, decreased breath sounds, and diaphoresis may also occur.
  • Pneumothorax. This life-threatening disorder causes acute dyspnea unrelated to the severity of pain. Sudden, stabbing chest pain may radiate to the arms, face, back, or abdomen. Other signs and symptoms include anxiety, restlessness, dry cough, cyanosis, decreased vocal fremitus, tachypnea, tympany, decreased or absent breath sounds on the affected side, asymmetrical chest expansion, splinting, and accessory muscle use. In patients with tension pneumothorax, tracheal deviation occurs in addition to these typical findings. Decreased blood pressure and tachycardia may also occur.
  • Poliomyelitis (bulbar). Dyspnea develops gradually in this disorder and worsens progressively. Additional signs and symptoms include fever, facial weakness, dysphasia, hypoactive deep tendon reflexes, decreased mental acuity, dysphagia, nasal regurgitation, and hypopnea.
  • Pulmonary edema. Commonly preceded by signs of heart failure, such as jugular vein distention and orthopnea, this life-threatening disorder causes acute dyspnea. Other features include tachycardia, tachypnea, crackles in both lung fields, a ventricular gallop (third heart sound [S3]), oliguria, thready pulse, hypotension, diaphoresis, cyanosis, and marked anxiety. The patient’s cough may be dry or may produce copious amounts of pink, frothy sputum.
  • Pulmonary embolism. This life-threatening disorder is characterized by acute dyspnea that’s usually accompanied by sudden pleuritic chest pain. Related findings include tachycardia, low-grade fever, tachypnea, a nonproductive cough or a productive cough with blood-tinged sputum, pleural friction rub, crackles, diffuse wheezing, dullness on percussion, decreased

    breath sounds, diaphoresis, restlessness, and acute anxiety. A massive embolism may cause signs of shock, such as hypotension and cool, clammy skin.
  • Sepsis. This potentially fatal disorder gradually causes dyspnea along with chills and sudden fever. As dyspnea worsens, it may be accompanied by tachycardia, tachypnea, restlessness, anxiety, decreased mental acuity, and warm, flushed, dry skin. Late findings include hypotension; oliguria; cool, clammy skin; and rapid, thready pulse.
  • Severe acute respiratory syndrome (SARS). SARS is an acute infectious disease of unknown etiology; however, a novel coronavirus has been implicated as a possible cause. Although most cases have been reported in Asia (China, Vietnam, Singapore, Thailand), cases have cropped up in Europe and North America. After an incubation period of 2 to 7 days, the illness generally begins with a fever (usually greater than 100.4° F [38° C]). Other symptoms include headache, malaise, a nonproductive cough, and dyspnea. The severity of the illness is highly variable, ranging from mild illness to pneumonia and, in some cases, progressing to respiratory failure and death.
  • Shock. Dyspnea arises suddenly and worsens progressively in this life-threatening disorder. Related findings include severe hypotension, tachypnea, tachycardia, decreased peripheral pulses, decreased mental acuity, restlessness, anxiety, and cool, clammy skin,
  • Tuberculosis. Dyspnea commonly occurs with chest pain, crackles, and a productive cough. Other findings are night sweats, fever, anorexia and weight loss, vague dyspepsia, palpitations on mild exertion, and dullness on percussion.
  • Tularemia. Also known as “rabbit fever,” this infectious disease causes dyspnea along with fever, chills, headache, generalized myalgia, a nonproductive cough, pleuritic chest pain, and empyema.
  • Inhalation injury. Dyspnea may develop suddenly or over several hours after inhalation of chemicals or hot gases. Increasing hoarseness, a persistent cough, sooty or bloody sputum, and oropharyngeal edema may also be present. The patient may also exhibit thermal burns, singed nasal hairs, and orofacial burns as well as crackles, rhonchi, wheezing, and signs of respiratory distress.
Monitor the dyspneic patient closely. Be as calm and reassuring as possible to reduce his anxiety, and help him into a comfortable position—usually high Fowler’s or a forward-leaning position. Support him with pillows, loosen his clothing, and administer oxygen if appropriate.
Prepare the patient for diagnostic studies, such as arterial blood gas analysis, chest X-rays, and pulmonary function tests. Administer a bronchodilator, an antiarrhythmic, a diuretic, and an analgesic, as needed, to dilate bronchioles, correct cardiac arrhythmias, promote fluid excretion, and relieve pain, respectively.
Normally, a child’s respirations are abdominal in infancy and gradually change to costal by age 7. Suspect dyspnea in an infant who breathes costally, in an older child who breathes abdominally, or in any child who uses his neck or shoulder muscles to help him breathe.
Both acute epiglottiditis and laryngotracheobronchitis (croup) can cause severe dyspnea in a child and may even lead to respiratory or cardiovascular collapse. Expect to administer oxygen, using a hood or cool mist tent.
Older patients with dyspnea related to chronic illness may not be aware initially of a significant change in their breathing pattern.
Tell the patient that oxygen therapy isn’t necessarily indicated for dyspnea. Encourage a patient with chronic dyspnea to pace his daily activities.