Dyspnoea or breathlessness can be defined as the unpleasant subjective awareness of sensation of breathing. It is the common symptom of the cardiac disease and the respiratory disease. In physiological terms, the patients usually perceive discomfort either from the increased ventilatory rate or drive, that can be provoked by the variety of factors or from a disease that causes enough reduction of ventilatory capacity. Other factors, including stimulations of J receptor leading to the amplification of ventilatory response in asthma or restrictive disorders, can also contribute.
It is obvious that diseases having dyspnoea may have a multifacteral etiology e.g., acute respiratory infections can stimulate respiratory rate as a result of fever, hypoxaemia and in serious cases, by acidoemia or hypercapnia. They can also reduce ventilatory capacity by increasing the bronchial resistance and also by restricting the ventilation because of pleural pain.
Different diagnosis in Patients with chronic Exertional Dyspnoea: -
Chronic obstructive pulmonary disease (COPD): -Very often there is a history of exertional dyspnoea over many years or months, with steady chronic decline exercise capacity. Chronic persistence cough and the daily production of sputum is the common rule and they can be a history of recurrent acute exacerbations of bronchitis. Wheezing on exercise can be prominent. In the late disease, especially if corpulmonale develops, orthopnoea, nocturnal breathlessness and ankle swelling many also supervene.
On Investigation, cyanosis may be at rest or on the trivial exertion, together with the expiratory wheeze, pursing of lips and intercostals indrawing, Antero-posterior diameter of chest may be increased and they may also be a reduced crico-sternal distance with ‘tracheal tug’ on inspiration. Chest radiograph shows signs of hyperinflation and bullae, arterial blood gases may expose hypoxaemia, hypercapnia and the raised plasma bicarbonate. There will often be the severe obstructive defeat on the spirometry which may or may not improve after the inhaled bronchodilators.
Heart Disease: - Sometime it is difficult to differentiate dyspnoea due to the heart disease. History of cough, wheezing and the nocturnal breathlessness may also occur in the cardiac failure as well as chronic obstructive pulmonary disease. History of angina or hypertension can be useful in implicating the cardiac cause. On investigation an increase in the heart size as judged by a displaced apex beat, the raised JVP and the cardiac murmurs may implicate cardiac disease. Chest radiograph and the ECG may provide the evidence of left ventricular or the arterial enlargement.
Interstitial or alvedar disease of the Lung: - Plenty of conditions may cause interstitial lung disease that may be actually difficult to distinguish from other conditions including the infiltrating malignancy and the chronic opportunistic lung infection. It is always imperative to elicit the detailed history including occupation and the exposure to birds and other sources of the organic agents that may provoke lung disease. Chest radiograph is always abnormal but the early change may be subtle. The pulmonary function tests normally show a restrictive defeat (reduced vital capacity) and the reduce gas transfer. Arterial blood gases may also show hypoxaemia or hoemeglobia desaturation can be detected by the oximetry, especially during formal exercise testing.
Disease of Chest Wall: - These are normally obvious on examination, history, and chest radiography. Whereas other rarer causes of the alveolar hyproventilation e.g. brain stem defeats, the primary alveolar hypoventilation and alveolar hypoventilation in the gross obesity may cause the disordered breathing and also cyanosis, these conditions are not normally associated with breathlessness.
Psychogenic breathlessness: - Patient may present with another classical symptoms of anxiety disorder. But it is important to be confidant of diagnosis since the anxiety is the highly prevalent symptoms and different organic conditions may present with the breathlessness along and especially in early stage, few, if any, physical sings. The historical features, including absence of symptoms on exercise, the relation to anxiety, feeling of ‘not being’ able to taking a deep enough breath and the frequent ‘sighing’ breathing may be suggestive of the anxiety-induced symptoms.
For excluding serious organic disease in the difficult cases it is necessary to proceed to the formal exercise testing since the psychogenic dyspnoea alone is not associated with the desaturation or the hypoxaemia even on the exercise. Sometimes this syndrome may develop into the full blown acute ‘hysterical’ hyperventilation attack that may appear dramatic and even lead to rigidity and the carp pedal spasm due to the acute respiratory alkalosis, secondary to the severe hyperventilation. This condition should be distinguished from other organic cause of acute sever breathlessness.
