Ministry of health of ukraine

Cough is the most frequent symptom of respiratory disease. It is caused by stimulation of sensory nerves in the mucosa of the pharynx, larynx, trachea and bronchi.

The explosive quality of a normal cough is lost in patients with respiratory muscle paralysis or vocal cord palsy. Paralysis of a single vocal cord gives rise to a prolonged, low-pitched, inefficient 'bovine' cough accompanied by hoarseness. Coexistence of an inspiratory noise (stridor) indicates partial obstruction of a major airway (e.g. laryngeal oedema, tracheal tumour, scarring or compression or an inhaled foreign body) and requires urgent investigation and treatment. Sputum production is common in patients with acute or chronic cough, and its nature and appearance can provide valuable clues as to the aetiology.

Causes of cough

Common causes

Clinical features

Pharynx

Post-nasal drip

History of chronic rhinitis

Larynx

Laryngitis, tumour, croup

Voice or swallowing altered, harsh or painful cough
Paroxysms of cough, often associated with stridor

Trachea

Tracheitis

retrosternal pain with cough

Bronchi

Bronchitis (acute) and COPD

Dry or productive, worse in mornings

Asthma

Usually dry, worse at night

Bronchial carcinoma

Persistent (often with haemoptysis)

Lung parenchyma

Tuberculosis

Productive, often with haemoptysis

Pneumonia

Dry initially, productive later

Bronchiectasis

Productive, changes in posture induce sputum production

Pulmonary oedema

Often at night

Interstitial fibrosis

Dry, irritant

Patients with chronic cough present more of a diagnostic challenge, especially those individuals with a normal examination, chest X-ray and lung function studies. In this context, cough can be explained by post-nasal drip secondary to nasal or sinus disease; cough-variant asthma (where cough may be the principal or exclusive clinical manifestation) or gastro-oesophageal reflux with aspiration. Ten to fifteen per cent of patients (particularly women) taking angiotensin-converting enzyme (ACE) inhibitors develop drug-induced chronic cough.

DYSPNOEA

Breathlessness or dyspnoea can be defined as the feeling of an uncomfortable need to breathe.

CAUSES OF DYSPNOEA

System

Acute dyspnoea at rest

Chronic exertional dyspnoea

Cardio -vascular

Acute pulmonary oedema

Chronic heart failure

Myocardial ischaemia

Respi -ratory

Acute severe asthma
Acute exacerbation of COPD
Pneumothorax
Pneumonia
* Pulmonary embolus
Acute respiratory distress syndrome
Inhaled foreign body
Lobar collapse
Laryngeal oedema (e.g. anaphylaxis)

COPD
Chronic asthma
Bronchial carcinoma
Interstitial lung disease (sarcoidosis, fibrosing alveolitis, pneumoconiosis)
Chronic pulmonary thromboembolism
Lymphatic carcinomatosis
Large pleural effusion(s)

Others

Metabolic acidosis (e.g. diabetic ketoacidosis, lactic acidosis, uraemia, overdose of salicylates,
Psychogenic hyperventilation

Severe anaemia
Obesity

CHRONIC EXERTIONAL DYSPNOEA

Chronic obstructive pulmonary disease (COPD)

The exertional dyspnoea in COPD typically varies little day to day, but exercise capacity falls over months or years. Patients usually report relief of dyspnoea at rest and overnight, a useful distinction from asthma. If bronchitis is present, chronic cough and sputum is usual, particularly in the mornings, but sputum may be absent when emphysema predominates. There is often a history of recurrent acute exacerbations of breathlessness, usually in winter. Most of the patients have a smoking history. In advanced disease may develop cor pulmonale

Asthma

Dyspnoea in asthma is associated with episodes of wheeze or chest tightness, usually worse in the morning. There may be a history of childhood wheeze, or of wheeze or rhinitis provoked by allergens. In exercise-induced asthma, wheeze and chest tightness typically come on immediately after exercise.

Heart disease

Left ventricular function can cause exertional dyspnoea. Orthopnoea, cough and wheeze may also be present, as in lung disease. A history of angina or hypertension may be useful in implicating a cardiac cause. On examination, an increase in heart size. The chest X-ray may show cardiomegaly and an ECG may provide evidence of left ventricular disease.

Pulmonary thromboembolism

Pulmonary thromboembolism often presents with acute breathlessness with or without chest pain. However, chronic pulmonary thromboembolic disease should be suspected in patients who present with more gradual onset of breathlessness.

Condition

History

Chest radiography

Other tests

Pulmonary oedema

Chest pain
Orthopnoea
Palpitations
A previous cardiac history*

Cardiomegaly
Upper zone vessel enlargement*
Overt oedema/pleural effusions*

ECG* (↓ left ventricular function)

Massive pulmonary embolus

Recent surgery or other risk factors
Chest pain
Previous pleurisy
Syncope*
Dizziness*

May be subtle changes only
Prominent hilar vessels
Oligaemic lung fields*

ECG*
V/Q scan*
CT pulmonary angiography*

Acute severe asthma

History of previous episodes, asthma medications, wheeze*

Hyperinflation only (unless complicated by pneumothorax)*

Acute exacerbation of COPD

Previous episodes (admissions)* If in type II respiratory failure may not be distressed

Hyperinflation*
Signs of emphysema
Signs of events precipitating exacerbation

Pneumonia

Prodromal illness*
Fever*
Rigors*
Pleurisy*

Pneumonic consolidation*

↑ CRP
↑ White cell count
Sputum and blood culture

Metabolic acidosis

Evidence of diabetes/renal disease*
Overdose of aspirin or ethylene glycol*

Normal

CHEST PAIN

HAEMOPTYSIS

CT scanning provides detailed images of the pulmonary parenchyma, mediastinum, pleura and bony structures. The contrast can be altered to highlight different structures such as the lung parenchyma, the mediastinal vascular structures or bone. Sophisticated software facilitates 3D reconstruction of the thorax and virtual bronchoscopy.

CT scanning is superior to chest radiography in determining the position and size of a pulmonary lesion and whether calcification or cavitation is present. It is now routinely used in the assessment of patients with suspected lung cancer and facilitates guided percutaneous needle biopsy. Information on tumour stage may be gained by examining the mediastinum, liver and adrenal glands.

High-resolution CT (HRCT) scanning uses thin sections to provide a detailed assessment of the pulmonary parenchyma and is particularly useful in assessing diffuse parenchymal lung disease, identifying bronchiectasis, and assessing the type and extent of emphysema.

CT pulmonary angiography (CTPA) is increasingly used in the diagnosis of pulmonary thromboembolism, where it may either confirm the suspected embolism or highlight an alternative diagnosis.

Ultrasound

Ultrasound is sensitive at detecting pleural fluid and may also be used to direct and improve the diagnostic yield from pleural biopsy. Information may also be provided on the anatomy of an empyema cavity and facilitate directed drainage.

Pulmonary angiography

Conventional pulmonary angiography is performed by passing contrast medium down a catheter inserted via the femoral vein into the main pulmonary artery. The technique represents the gold standard for the diagnosis of pulmonary embolism but is rarely used, particularly now that CTPA is widely available. It is essential in the investigation of patients with pulmonary hypertension, providing information on pulmonary and right heart pressures.

ENDOSCOPIC EXAMINATION

Laryngoscopy

The larynx may be inspected indirectly with a mirror or directly with a laryngoscope. Fibreoptic instruments allow a magnified view to be obtained.

Bronchoscopy

The trachea and larger bronchi may be inspected by either a flexible or a rigid bronchoscope. Flexible bronchoscopy may be performed under local anaesthesia with sedation as an outpatient. Structural changes, such as distortion or obstruction, can be seen. Abnormal tissue in the bronchial lumen or wall can be biopsied, and bronchial brushings, washings or aspirates can be taken for cytological or bacteriological examination. Small biopsy specimens of lung tissue taken by forceps passed through the bronchial wall (transbronchial biopsies) may reveal sarcoid granulomas or malignant diseases and may be helpful in diagnosing certain bronchocentric disorders (e.g. hypersensitivity pneumonitis, cryptogenic organising pneumonia), but are generally too small to be of diagnostic value in other diffuse parenchymal pulmonary disease. Transbronchial needle aspiration (TBNA) may sample mediastinal lymph nodes and assist with staging of lung cancer. Endobronchial ultrasound is currently undergoing assessment as a method of directing and enhancing the diagnostic yield of TBNA.

Rigid bronchoscopy requires general anaesthesia but is more advantageous in certain situations e.g. evaluating massive haemoptysis or removing foreign bodies. In addition, endobronchial laser therapy and endobronchial stenting may be more easily performed with rigid bronchoscopy.

SKIN TESTS

The tuberculin test may be of value in the diagnosis of tuberculosis. Skin hypersensitivity tests are useful in the investigation of allergic diseases.

Abbreviation

FEV₁

FVC

VC

PEF

TLC

FRC

RV

TL_CO

K_CO

In diseases characterised by airway narrowing (e.g. asthma, bronchitis and emphysema) maximum expiratory flow is limited by dynamic compression of small intrathoracic airways, some of which close completely during expiration, limiting the volume which can be expired. Hyperinflation of the chest results, and can become extreme if elastic recoil is also lost due to parenchymal destruction, as in emphysema. In contrast, diseases which cause lung inflammation and/or scarring and fibrosis are characterised by progressive loss of lung volume with normal expiratory flow rates. Gas exchange is impaired by both parenchymal destruction (emphysema) and by interstitial disease, which disrupts the local matching of ventilation and perfusion.

In respiratory function testing, airway narrowing, lung volume and gas exchange capacity are quantified and compared with normal values adjusted for age, gender, height and ethnic origin.

Airway narrowing is assessed by forced expiration into a peak flow meter or a spirometer. Peak flow meters are cheap and convenient for home monitoring (e.g. detection and monitoring of asthma) but values are effort-dependent. The forced expiratory volume in 1 second (FEV₁) and vital capacity (VC) are obtained from maximal forced and relaxed expirations into a spirometer. FEV₁ is disproportionately reduced in airflow obstruction resulting in FEV₁/VC ratios of less than 70%. When airflow obstruction is seen, spirometry should be repeated following inhaled short-acting β₂-adrenoceptor agonists (e.g. salbutamol); reversibility to normal is suggestive of asthma. To distinguish large airway narrowing (e.g. tracheal stenosis or compression) from small airway narrowing, flow-volume loops are recorded during maximum expiratory and inspiratory efforts.

Lung volume can be measured by dilution of an inhaled inert gas (usually helium) or by determining the pressure/volume relationship of the thorax by body plethysmography. The former method measures the volume of intrathoracic gas which mixes quickly with tidal breaths, while the latter measures total intrathoracic gas volume, including poorly ventilated areas such as bullae.

FEV₁

VC

FEV₁/VC

TL_CO

K_CO

TLC

RV

To measure the capacity of the lungs to exchange gas, patients inhale a test mixture of 0.3% carbon monoxide, which is avidly bound to haemoglobin in pulmonary capillaries. After a short breath-hold, the rate of disappearance of CO into the circulation is calculated from a sample of expirate, and expressed as the TL_co or carbon monoxide transfer factor. Helium is also included in the test breath to allow calculation of the volume of lung examined by the test breath. Transfer factor expressed per unit lung volume is termed K_co.

Exercise tests

Resting measurements are sometimes unhelpful in early disease or in patients complaining only of exercise-induced symptoms. Exercise testing with spirometry before and after can be helpful in demonstrating exercise-induced asthma. Walk tests include the self-paced 6 minute walk and the externally paced incremental 'shuttle' test. These can provide simple, repeatable assessments of disability and response to treatment. Finally, cardiopulmonary exercise testing using cycle or treadmill exercise with measurement of metabolic gas exchange, ventilation and cardiac responses is useful in distinguishing cardiac limitation from respiratory limitation in the breathless patient.