Breathlessness/Dyspnoea/Shortness of breath (SOB)/Air hunger

Definition: It can be defined as the feeling of an uncomfortable need to breath.

Or,

The American Thoracic Society defines dyspnea as: "A subjective experience of breathing discomfort that consists of qualitatively distinct sensations that vary in intensity."Other definitions describe it as "difficulty in breathing"," disordered or inadequate breathing", "uncomfortable awareness of breathing", and as the experience of "breathlessness" (which may be either acute or chronic).
Dyspnea is distinct from labored breathing, which is a common physical presentation of respiratory distress.

Grading:

MRC Breathlessness Scale:

Grade Degree of dyspnea
0 no dyspnea except with strenuous exercise
1 dyspnea when walking up an incline or hurrying on the level
2 walks slower than most on the level, or stops after 15 minutes of walking on the level
3 stops after a few minutes of walking on the level
4 with minimal activity such as getting dressed, too dyspneic to leave the house

Causes:

[A]Cardiovascular:

1. Acute dysponea:
• Acute pulmonary oedema.
• Myocardial ischaemia(angina equivalent)
2. Chronic exertional dyspnoea:
• Chronic heart failure.
• Myocardial ischaemia(angina equivalent)

[B]Respiratory cause:

1. Acute dysponea at rest:
• Acute severe asthma.
• Acute exacerbation of COPD.
• Pneumothorax.
• Pneumonia.
• Pulmonary embolism.
• ARDS(acute respiratory distress syndrome)
• Lobar collapse.
• Laryngeal oedema(e.g anaphylaxis)

2. Chronic exertional dysponea:
• COPD.
• Chronic asthma.
• Bronchial carainoma.
• Interstitial lung disease: e.g. Sarcoidosis.
• Chronic pulmonary thromboembolism.
• Lymphatic carcinomatosis.
• Large pleural effusion.

[C]Others cause:

1. Acute:
• Metabolic acidosis (e.g. diabetic ketoacidosis, lactic acidosis, uraemia, overdose of salicylates).
• Psychogenic hyperventilation(anxiety/panic related)
2. Chronic: Sever anaemia, obesity.

Differential diagnosis:

1. Acute coronary syndrome
2. Congestive heart failure
3. Chronic obstructive pulmonary disease
4. Asthma
5. Pneumothorax
6. Pneumonia
7. Pulmonary embolism
8. Anaemia

Treatment: In those who are not palliative the primary treatment of shortness of breath is directed at its underlying cause. Extra oxygen is effective in those with hypoxia; however, this has no effect in those with normal blood oxygen saturations, even in those who are palliative.

Physiotherapy: Individuals can benefit from a variety of physical therapy interventions. Persons with neurological/neuromuscular abnormalities may have breathing difficulties due to weak or paralyzed intercostal, abdominal and/or other muscles needed for ventilation. Some physical therapy interventions for this population include active assisted cough techniques, volume augmentation such as breath stacking, education about body position and ventilation patterns and movement strategies to facilitate breathing.

Palliative: Along with the measure above, systemic immediate release opioids are beneficial in reducing the symptom of shortness of breath due to both cancer and non cancer causes. There is a lack of evidence to recommend midazolam, nebulised opioids, the use of gas mixtures, or cognitive-behavioral therapy.

Reference:

1. Davidson’s Principle and Practice of Medicine,21st edition
2. Wikipedia the free encyclopedia.