Discuss about the Natural History of Emphysema.
The Chronic obstructive pulmonary disease is the commonest respiratory disorder caused by two distinct pathological entities i.e. emphysema and chronic bronchitis. These two entities mostly occur together in varying proportion in the same patient.
Emphysema is an obstructive lung disease leading to obstruction in the airways due to loss of elastic recoil properties of the lungs. It is a progressive disease with over-inflation of alveoli (alveoli are the air sacs within the lungs) leading to the destruction of air passages. In response to alveolar tissue loss, there occurs premature closure of airways on expiration causing shortness of breath.
Factors causing Initiation and progression of the disease are unclear. Male sex, smoking, age, and anthracosis grade are the noticeable factors affecting the development of emphysema.
The Process of destruction usually takes 20 years to manifest clinically(Polkey,2009).
The lungs are found in chest cavity on either side i.e. right and left side. The lungs are divided into lobes: right lung has three lobes i.e. lower, middle and upper lobe whereas left lung has two lobes i.e. upper and lower. (Nene,2011)
Air enters the lungs via trachea (windpipe).
Emphysema develops in response to inhaled irritants as a chronic inflammatory reaction. This inflammatory state is summed up by severe bacterial infection. Macrophages, eosinophils, granulocytes and neutrophils are the inflammatory cells transporting the antigen to BALT (bronchial associated lymphatic tissue layer) leading to epithelium damage of the lung. Tc1 lymphocytes are involved in persons who smoke. Lung damage is brought about by oxidative stress (due to the presence of free radicals in cigarette smokers) and connective tissue breakdown in the lungs.
This connective tissue breakdown in the lungs leads to emphysema. Inflammation and scarring occur within the lungs which further narrows the airways. This narrowing contributes to entrapment of air into the alveolar sac leading to shortness of breath. Exhalation becomes more difficult as the pressure in chest becomes more due to entrapped air leading to hyperinflation(Theorotical analysis,2003).
The airway repair process further exacerbates the anatomical derangements by neovascularisation and abnormal fibroblastic development. It leads to bronchial edema (by mucus hyperplasia), hypertrophy of smooth muscles and fibrosis resulting in further narrowing of smaller airways.
- Non-audible, quiet breath sounds due to increased thoracic volume
- Use of accessory muscles of respiration
- On inspiration, supraclavicular fossae and intercostals spaces are drawn in.
- On inspiration, exaggerated jugular venous emptying
- On expiration, jugular venous distend
- A-P diameter of chest increases affecting chest expansion
- Right ventricular hypertrophy develops
Patients presents with wheezy breathlessness without or with a productive cough. Some complaints of more sputum production in the early morning. With the presence of infection, sputum becomes more copious and purulent. Breathlessness is more commonly seen while climbing stairs or inclined walking.
According to carbon dioxide retention and under-ventilation, patients can be classified into two main groups:-
Blue-bloater: these patients are obese with the production of copious infected sputum accompanied by breathlessness and wheezing. Hypoxemia and hypercapnia are seen during acute attacks. Blue bloaters show severe airflow obstruction with normal lung capacities but increased residual volume.
Pink-puffers: these patients are thin with no sputum production and are severely breathless at rest. Severe airway obstruction can be seen with increased lung capacity. Their sensitivity remains normal to carbon dioxide saturation.
Affects of emphysema on the surrounding structures
Emphysema affects the surrounding structures to a greater extent. All lung volumes will be reduced esp. FEV1 (forced expiratory volume in 1 second), PEFR (peak expiratory flow rate), and FVC (forced vital capacity).
In chronic conditions, FEV1 and PEFR are reduced to markable level. Emphysema affects the anatomical structures of lungs in an irreversible manner.
The acute effect of emphysema is patient's difficulty in breathing. Patients may have effortful breathing after exercise, in hot weather, and in stressful situations. Fatigue is a more common effect, caused by a decrease in oxygen supply to the body. As the disease progress, Patients develop anxiety and weight loss. Oedema (fluid collects in the extremities) in emphysematic patients also affects the body.
Sputum culture is done to rule out the invading organism (H.influenzae and S. Pneumomiae)
During infection, Blood count shows polymorphonuclear leucocytosis.
Chest X-Ray showed reduced vascular markings and increased radiolucency of lung fields.
The main objective of treatment is to relieve airway obstruction.
Infecting organisms are usually H.influenzae or S.pneumoniae. therefore, suitable oral antibiotic regimes (co-trimoxazole, Ampicillin, Amoxicillin, Oxytetracycline etc.) Are advised for 5-7 days.(Goyal,2008)
Bronchodilator therapy is very effective. They are administered as aerosols such as terbutalin, salbutamol, or rimiterol. Systemic corticosteroids can also be given in patients with severe airway obstruction.
Oxygen therapy is given to avoid danger of carbon dioxide retention
Long run management include:
Patients must be advised to stop smoking.(Bednarak,2009)
Obese patients are advised to lose weight as this may improve exercise tolerance.
Physiotherapy focuses on three main problems in emphysema patients i.e. breathlessness, decreased exercise tolerance and increased secretions.
Chest clearance programs are very effective with postural drainage. Breathing exercises (diaphragmatic breathing exercises) are for controlling breath during attacks of dyspnoea. (Kant,2006).Pulmonary rehabilitation is done in each patient to improve and prevent the disease.
- Heart failure
- Lung infections
- cor pulmonale i.e. right ventricular failure and pulmonary hypertension.
- Bullae may develop large enough to compress surrounding lung area.(Meyers,2009)
Progression and severity of emphysema predict the prognosis of the disease. Emphysema staging help determines the life expectancy of the patient.(Jama,2005)
According to GOLD emphysema staging:
Stage I. Mild emphysema- FEV1 ≥ 80% of normal
StageII. Moderate emphysema- FEV1 ≤ 50% of normal
Stage III. Severe emphysema- FEV1 ≤ 30% of normal
Stage IV. Very severe- FEV1 < 30% of normal
Higher the patient emphysema staging, lower their life expectancy.
This report concludes that emphysema is a chronic obstructive pulmonary disease causing irreversible damage to lung tissue. Smoking is the major causative factor in its onset. Severity and progression of the disease determine the life expectancy of the person suffering from emphysema. New studies are still going on for the early diagnosis and treatment of emphysema.
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