Examination of the respiratory system Medical Assignment Help

The nose

The anterior part of the nose can be examined using a nasal speculum and light source. In allergic rhinitis the mucosa lining the nasal septum and inferior turbinate appears swollen and a dark red or plum colour. Nasal polyps can also be identified, as can a frequent site of nasal haemorrhage (Little’s area).

The chest

Radiology has become an essential part of examination of the chest. Diseases such as tuberculosis or lung cancer may not be detectable on clinical examination but are obvious on the chest X-ray. Conversely, the abnormal physical signs in asthma or chronic bronchitis may be associated with a normal chest X-ray.

INSPECTION

The patient should be observed carefully, paying particular attention to mental alertness, cyanosis, breathlessness at rest, use of accessory muscles and any deformity or scars on the chest. A coarse tremor or flap of the outstretched hands indicates CO2 intoxication. Prominent veins on the chest may imply obstruction of the superior vena cava. The jugular venous pressure should be assessed.
Central cyanosis is assessed on the colour of the tongue and lips, and indicates a Pa02 below 6 kPa. Peripheral cyanosis is noted on the fingernails and skin of the extremities and in the absence of central cyanosis is due to a reduced peripheral circulation. Finger clubbing is present when the normal angle between the base of the nail and the nail fold is lost. The base of the nail is fluctuant owing to increased vascularity, and there is an increased curvature of the nail in all directions, with expansion of the end of the digit. Some causes  of clubbing are given. Clubbing is not seen in chronic bronchitis.

PALPATION

The position of the mediastinum should be ascertained by checking whether the trachea is central and whether the cardiac apex is in the fifth intercostal space. The supraclavicular fossa is examined for enlarged lymph nodes. The distance between the sternal notch and the cricoid cartilage (three to four finger breadths in full expiration) is reduced in patients with severe airflow limitation. Movement of the upper and lower parts of the chest should be assessed. Compression of the chest laterally and anteroposteriorly may produce a localized pain suggestive of a rib fracture.

PERCUSSION

This should be performed symmetrically on both sides for comparison. Liver dullness is usually detected anteriorly at the level of the sixth rib. Liver and cardiac dullness are lost with over-inflated lungs. The percussion note is dull over consolidation and stony dull over a pleural effusion.

AUSCULTATION

The diaphragm of the stethoscope should be used. The patient is asked to take deep breaths through the mouth.

Physical signs of respiratory disease.

Physical signs of respiratory disease.

Some causes of finger clubbing.

Some causes of finger clubbing.

Inspiration sounds more prolonged than expiration. Healthy lungs filter off most of the high-frequency component, mainly due to turbulent flow in the larynx. Normal breath sounds are harsher anteriorly over the upper lobes (particularly on the right) and described as vesicular. Vesicular sounds may be loud in a thin healthy subject or soft in patients with emphysema. Breath sounds are reduced or absent in a pneumothorax, over a pleural effusion or when the bronchus to a lobe is obstructed by a carcinoma.
BRONCHIAL BREATHING. These abnormal breath sounds are heard best over consolidated or collapsed lung and sometimes over areas of localized fibrosis or bronchiectasis. Such areas conduct the high-frequency hissing component of breath sounds well. Characteristically, the noise heard during inspiration and expiration is equally long but separated by a short silent phase. Bronchial breathing can be imitated by listening over the larynx, particularly if the subject breathes with the vocal cords in a position to sound a whispered ‘eee’.

Whispering pectoriloquy (whispered, and therefore higher-pitched, sounds heard distinctly) invariably accompanies bronchial breathing.
ADDED SOUNDS. The terms rhonchi, rales and crepitations are best discarded and replaced with the simple terms wheezes and crackles.

WHEEZE is usually heard during expiration and results from vibrations in the collapsible part of the airways when apposition occurs as a result of the flow-limiting mechanisms. Wheezes are heard in asthma and in chronic bronchitis and emphysema, but are not invariably present. In the most severe cases of asthma a wheeze may not be heard, as the airflow may be insufficient to generate the sound. Wheezes may be monophonic (single large airway obstruction) or polyphonic (narrowing of many small airways).
CRACKLES. These brief crackling sounds are probably produced by opening of previously closed bronchioles, and their timing during breathing is of significanceearly inspiratory crackles are associated with diffuse airflow limitation, whereas late inspiratory crackles are characteristically heard in pulmonary oedema, fibrosis of the lung and bronchiectasis. They may be described as fine or coarse but this is of no significance.
PLEURAL RUB. This is a creaking or groaning sound that is usually well localized. It is indicative of inflammation and roughening of the pleural surfaces, which normally glide silently over one another.
VOCAL RESONANCE AND FREMITUS. Healthy lung attenuates high-frequency notes, leaving the booming low-pitched components of speech. Consolidated lung has the reverse effect, transmitting the high frequencies; the spoken word then takes on a bleating quality. Whispered speech can barely be heard over healthy lung, whereas consolidation allows its clear transmission. Sonorous sounds such as ‘ninety-nine’ are well transmitted across healthy lung to produce vibration that can be felt over the chest wall. Consolidated lung transmits these low-frequency noises less well, and pleural fluid severely dampens or obliterates the vibrations altogether.

Additional bedside tests

Since so m ny patients with respiratory disease have airflow limitation, airflow should be routinely measured at the bedside using a peak flow meter. This will provide a much more accurate assessment than any physical sign.

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