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Acute dyspnea (shortness of breath) overview

Published: March 24, 2017. Updated: January 15, 2020

Dyspnea (shortness of breath) is a term used to characterize a subjective experience of breathing discomfort that is comprised of qualitatively distinct sensations that vary in intensity.

1. Acute dyspnea

Acute dyspnea is shortness of breath that lasts between hours to days and is always an alarm symptom that requires prompt attention. A chest x-ray is requested to rule out respiratory, cardiac and mediastinal disease.

If the patient is unable to complete a full sentence without pausing then move quickly to stabilize the patient hemodynamically and delay the medical interview for later.

The following algorithm helps narrow down the causes for acute dyspnea.

1. Dyspnea + wheezing, cough

  • Aspiration (historyof foreign body inhalation or inhalation of noxious agents)
  • Anaphylaxis or angioedema (lip swelling, hives in addition to wheezing)
  • COPD exacerbation
  • Other pulmonary disease (chest x-ray)

2. Dyspnea + fever

3. Exertional dyspnea. Dyspnea on mild exertion is indicative of left sided heart failure is usually accompanied by othermanifestations (orthopnea, paroxysmal nocturnal dyspnea).

4. Positional dyspnea: pericardial disease.

  • Jugular venous distention: pericardial effusion.
  • Beck’s triad (hypotension, jugular venous distention, muffled heart sounds): cardiac tamponade.
  • Orthopnea: dyspnea on lying flat.
  • Trepopnea: on lateral decubitus - while lying on one side but not on the other. Disease of one lung, one major bronchus, or chronic congestive heart failure.
  • Platypnea upright position and is relieved with recumbency. COPD.  Platypnea in association with orthodeoxia (arterial deoxygenation in the upright position) has been reported in several forms of cyanotic congenital heart disease.

5. Dyspnea + pleuritic chest pain (sharp, unilateral chest pain that increases with respiration)

6. Dyspnea + confusion, drowsiness (metabolic diseases)

  • Known or suspicious history of diabetes or renal failure: DKA or metabolic acidosis.
  • Suicidality or chronic pain: aspirin overdose, panic disorder, primary hyperventilation.

7. Neuromuscular manifestations

Chronic dyspnea

Chronic dyspnea + cough (pulmonary: chest x-ray and if needed pulmonary function tests, bronchoscopy)

  • Cough + wheezing: asthma (episodic dyspnea).
  • Cough without wheezing: Other pulmonary—> chest x-ray (interstitial lung disease, malignancy, chronic pneumonia, pleural effusion).
  • Cardiac disease.
  • Metabolic: anemia, acidosis, thyrotoxicosis.

Chronic dyspnea without cough:

  • Pulmonary hypertension, cardiomyopathy, deconditioning, anemia, neuromuscular disease.

Respiratory patterns

Several ventilation patterns have been described in the comatosed/unconscious patient. These are not clinically usefulas they are either rare/not specific.

  • Cheyne-Stokes breathing can occur in elderly. Alternating episodes of hyperventilation and apnea. Seen in pending herniations, extensive cortical lesions, or brainstem damage
  • Apneustic breathing is very rare. sudden pauses of inspiration and is due to a lesion of the pons.
  • Ataxic breathing is irregular and is due to a lesion (damage) of the medulla.


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