Dyspnea (Difficulty Breathing) – Causes of Shortness of Breath

What is Dyspnea?

Dyspnea is the medical term for difficulty breathing, typically presenting as shortness of breath or labored breathing. The term dyspnea encompasses a number of different breathing difficulties, which may be vary in sensation and experience among patients. Despite the differences, the sensation is usually that of strained or uncomfortable breathing that is not normal for the patient. Dyspnea may or may not present with any abnormal breathing sounds, like a stridor or wheeze.

The pattern of breathing (rate and depth) is regulated by the levels of carbon dioxide and oxygen in the blood and the entire process is controlled and maintained by the central nervous system in conjunction with the respiratory system and muscles of respiration as well as the cardiovascular system. Any disturbance within one or more of these systems can lead to dyspnea. Apart from neurological, respiratory and cardiovascular causes, psychological, mechanical and environmental factors may also be responsible for dyspnea.

The labored breathing may occur as result of the patient feeling like they are being ‘starved’ of air or not getting enough air or difficulty when breathing in (inspiration) or out (expiration). In order to compensate, a patient may be seen drawing long or ‘hard’ (forceful) breaths or there is shallow and rapid breathing. It is important to identify acute (sudden or short term) dyspnea from a chronic (persistent, long standing) case in order to diagnose the cause. Shortness of breath due to strenuous physical activity is normal and a quick recovery can be expected once at rest.

Acute Causes of Dyspnea

Any difficulty breathing (dyspnea) that is of a sudden onset, developing within minutes, should be treated as emergency and immediate medical attention is necessary. Most of these acute causes are life threatening if it is not managed properly and should be overseen by a medical doctor.

Shortness of breath that develops within hours or even in a day or two (subacute) also require medical attention as it may precede the onset of a potentially life threatening condition. It is important to take note of any other signs and symptoms that are appearing along with the shortness of breath as this will assist your doctor with the final diagnosis.


  • Usually of sudden onset after eating certain foods, insect bits or stings or after taking certain medication.
  • May be accompanied by itching of the skin, itchy throat and eyes.
  • Nausea, vomiting and/or diarrhea.
  • Difficulty speaking in severe cases.


  • History of angina or coronary artery disease.
  • Symptoms similar to a heart attack, particularly chest pain radiating to the arm, jaw, abdomen or back.
  • Triggered by physical or emotional stress.
  • Pain usually eases with TNT spray or tablets.


  • History of asthma.
  • Abnormal breathing sounds, specifically wheezing.
  • Triggered or exacerbated after exposure to stimuli like allergens or exercise.

Status Asthmaticus

  • This is a severe attack which is unresponsive to usual measures and medication (status asthmaticus) .
  • Pale (pallor) to bluish skin discoloration.
  • Anxiety and fearful.
  • Little or no breathing sounds, even a wheeze is not as loud.
  • Difficulty or inability to speak.
  • Confusion and unresponsive.
  • Loss of consciousness.

Acute Bronchitis

  • Often preceded by a viral upper respiratory tract infection like the flu or common cold.
  • Productive cough, with white to yellow or brown sputum.
  • Intermittent episodes of abnormal breathing sounds.
  • Coughing with chest pain.
  • Fever.
  • Bronchitis may be accompanied by inflammation higher up the respiratory tract like laryngitis or pharyngitis or lower down like pneumonia.

Diaphragmatic Paralysis

  • May be one sided or affect both sides.
  • Dyspnea in one side paralysis is usually mild and occurs mainly on exertion.
  • Bilateral paralysis is usually severe with rapid shallow breathing

Foreign Body in the Airway

  • Usually occurs in infants and children.
  • The child becomes restless and agitated.
  • Difficulty in talking or crying.
  • Abnormal breathing sounds like a stridor.
  • Dyspnea of sudden onset which may be accompanied by choking or coughing.
  • Gagging may be noticed immediately if there is almost complete obstruction of the airway.

Heart Failure

  • Swelling of the legs, arms of generalized swelling throughout the body.
  • May have been experiencing dyspnea for weeks or months prior to sudden exacerbation.
  • Cold and clammy to touch, especially the lower limbs.
  • Dyspnea aggravates when lying flat.
  • Fluid in lungs with bubbling or crackling breathing sounds.

Myocardial Infarction (Heart Attack)

  • History of coronary artery disease, hypertension, hypercholesterolemia.
  • Breastbone pain (also refer to Heart Chest Pain).
  • Pain radiating down the arm, to the jaw, abdomen or back. While a left arm pain is thought to be the main symptom, some patients do report pain down the right arm or both arms.
  • Perspiration. A cold and clammy feel to the skin may indicate shock.
  • Anxiety and fearful.
  • Dizziness or fainting.
  • Mental confusion.

Pericardial Effusion

  • Breastbone pain.
  • Difficulty and painful breathing especially when lying down.
  • Cough.
  • Fever.
  • Fatigue.
  • Palpitations.


  • Sudden onset.
  • May be due to trauma with obvious signs of chest wall injury or may be spontaneous with no clear external signs.
  • Diminished breathing sounds.
  • Rapid breathing, sometimes with gasping for air.
  • Chest pain, usually unilateral (one side)
  • Chest pain with coughing.
  • Fatigue.
  • Pale to blue discoloration of the skin.


  • Fever with chills.
  • Chest pain when breathing.
  • Productive cough.
  • Headache, muscle pain and sweating.
  • Bubbling or crackling sounds when breathing.

Psychiatric Causes

  • Often triggered by emotional situations.
  • Gasping for air – hyperventilation.
  • History of anxiety or depression.

Pulmonary Embolism

  • History of pulmonary embolism risk factors like DVT, pregnancy, family history, recent surgery.
  • Chest pain similar to that of a heart attack.
  • Coughing, with blood in the mucus.
  • Rapid breathing.
  • Rapid pulse.
  • Other signs of shock.

Smoke or Toxin Inhalation

  • Preceded by smoke or toxic fume inhalation.
  • May be accompanied by a burning sensation of the nasal passages and eyes.
  • Often of a sudden onset but may develop slowly over months in occupational exposure.

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