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📋 THE RESPIRATORY SYSTEM — MacLeod's Clinical Examination

Complete Study Notes: History & Physical Examination

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ANATOMY AND PHYSIOLOGY — Key Surface Landmarks

• At the end of tidal expiration, the dome of the diaphragm extends high into the thorax, level with the anterior end of the fifth rib, slightly lower on the left
• The lower lateral ribs overlie the liver on the right and the stomach and spleen on the left, with the parietal pleura extending lower than the lungs on the lateral chest wall
• Posteriorly, the lungs extend much lower, approaching the 12th rib on full inspiration

The Lung Apex

• Pain and numbness in the inner aspect of the upper arm
• Wasting of the small hand muscles
• The upper thoracic sympathetic outflow to the eye may be compromised → constricted pupil and ptosis (Horner's syndrome)

Physiology

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THE HISTORY

The key features of the history are summarised in Box 5.1.

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BOX 5.1 — Respiratory History-Taking/Documentation Framework

History of Presenting Symptoms

• Breathlessness
• Wheeze
• Cough
• Sputum/haemoptysis
• Chest pain
• Fever/rigors/night sweats
• Weight loss
• Sleepiness

Past Medical History

• Respiratory disease
• Other illness/hospital encounters

Drug and Allergy History

• Drugs causing or relieving respiratory symptoms
• Allergies to pollens/pets/dust; anaphylaxis

Social and Family History

• Family history of respiratory disease
• Home circumstances/effect of and on disease
• Smoking
• Occupational history

Systematic Review

• Systemic diseases involving the lung
• Risk factors for lung disease

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COMMON PRESENTING SYMPTOMS

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1. BREATHLESSNESS (Dyspnoea)

• Stimulation of intrapulmonary afferent nerves by interstitial inflammation or thromboembolism
• Mechanical loading of respiratory muscles by airflow obstruction or reduced lung compliance in fibrosis
• Hypoxia due to ventilation/perfusion mismatch, stimulating chemoreceptors

Specific Questions to Ask:

• How did the breathlessness start?
  • Instantaneous onset → pneumothorax, pulmonary embolus or anaphylaxis
  • Paroxysmal nocturnal dyspnoea → may wake a sleeping patient with breathlessness
  • Onset over hours → asthma, acute pulmonary oedema, lobar pneumonia, acute hypersensitivity pneumonitis
  • Insidious onset → evolving pleural effusion, COPD, interstitial lung disease, lung tumours
• How is your breathing at rest and overnight?
  • Asthma commonly wakes patients
  • Most patients with COPD are comfortable at rest and when asleep but struggle with exertion
  • Orthopnoea (breathlessness on lying down) → feature of heart failure; also occurs in severe airflow obstruction or diaphragmatic weakness (weight of abdomen displaces diaphragm cranially, compromising vital capacity)
• Does your breathlessness vary from day to day or week to week?
  • Variable → typical of asthma
  • Consistent daily limitation → COPD or interstitial lung disease
• Can you tell me something you do that would make you breathless? How far can you walk on a good day?
  • Reveals the disability caused by respiratory disease
  • Record restrictions on normal activity or work and the corresponding MRC breathlessness score
  • Enquire: 'When was the last time you could walk to the shops / play a full round of golf?'
• When does the breathlessness start?
  • Asthma induced by exercise frequently appears only after exercise during early recovery, because sympathetic drive during exercise defends airway patency
• Is it worse on waking in the morning and relieved by clearing sputum?
  • Common in COPD and bronchiectasis

Psychological aetiology: Certain phrases strongly suggest a psychological cause, particularly 'I feel I can't get enough air (or oxygen) into my chest.' In patients with hyperventilation due to anxiety, this is frequently accompanied by a normal measured vital capacity. Associated symptoms induced by hypocapnia include digital and perioral paraesthesia, light-headedness and chest tightness.

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BOX 5.2 — MRC Breathlessness Scale

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FIG. 5.2 — Diagnostic Approach to Breathlessness

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2. WHEEZE

• The rattling inspiratory and expiratory sounds caused by loose, mobile secretions in the upper airways
• The louder, dramatic croak of stridor caused by obstruction in the trachea or large airways

Patients may be unaware of nocturnal wheeze, which may be noticed only by their bed partner.

Ask:

• Is the wheeze worse during or after exercise? If it occurs during exercise and limits it → COPD; in asthma, wheeze and tightness usually appear after exercise
• Do you wake with wheeze during the night? → suggests asthma
• Do you have hay fever or other allergies? Atopy is common in allergic asthma. A family history of wheeze or asthma is common.

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3. COUGH

Ask about:

• Duration of the cough
• Whether it is present every day
• If it is intrusive/irresistible or whether the patient coughs deliberately to clear a perceived obstruction (throat clearing)
• Whether it produces sputum — if so, how much, and what colour?
• Any haemoptysis?
• Any triggers (such as swallowing, cold air, during or after exercise, allergens)

Bovine cough: In patients with malignancy at the left hilum, damage to the left recurrent laryngeal nerve may paralyse the left vocal cord, making it impossible for the patient to close the glottis and generate a normal explosive cough. The resulting hoarse forced expiration without the initial explosive glottal opening is called a 'bovine cough.'

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BOX 5.3 — Causes of Chronic Cough and Accompanying Clues in the History

Additional Points to Note:

• Smoking increases the likelihood of chronic bronchitis or lung cancer
• Associated clinical features:
  • Wheeze - may signal cough-variant asthma
  • Heartburn or reflux - gastro-oesophageal reflux commonly triggers cough
  • Altered voice or swallowing - consider laryngeal causes
• Drug history, especially angiotensin-converting enzyme (ACE) inhibitors

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4. SPUTUM

Colour:

• Clear (mucoid): COPD/bronchiectasis without current infection
• Yellow (mucopurulent): acute lower respiratory tract infection/asthma
• Green (purulent): current infection - acute disease or exacerbation of chronic disease, such as COPD. In bronchiectasis (and COPD), the colour and volume of sputum may be used to guide the need for antibiotics; whereas in asthma, mucopurulent sputum may be the result of sputum eosinophilia
• Red/brown (rusty): pneumococcal pneumonia
• Pink (serous/frothy): acute pulmonary oedema

Volume:

• Establish the volume produced over 24 hours: small amounts into a tissue or enough to fill a spoon(s), eggcup(s) or cup(s)
• Compare the current volume with the patient's baseline volume
• Large volumes of sputum over long periods → bronchiectasis

Consistency:

• An increase in stickiness (viscosity) may indicate exacerbation in bronchiectasis
• Occasionally, sputum is produced as firm 'plugs' by patients with asthma, sometimes indicating underlying allergic bronchopulmonary aspergillosis
• Large volumes of frothy secretions over weeks/months → feature of the uncommon bronchoalveolar cell carcinoma

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5. HAEMOPTYSIS

Enquire about:

• Was the blood coughed up from the chest? Blood in the mouth may be vomited, may have come from the nose in epistaxis, or may appear on chewing or tooth brushing in patients with gum disease
• When did blood appear, how much blood, were there associated symptoms and over what time period was it present?
• Any fever/symptoms of infection? Acute or chronic bronchial infections, including tuberculosis, often trigger haemoptysis
• Recurrent blood streaks in clear sputum → prompt a search for lung cancer
• Recurrent blood streaks in purulent sputum over years → suggests bronchiectasis
• A sudden episode of haemoptysis with pleuritic pain and breathlessness → pulmonary embolism
• Large volumes of haemoptysis (>20 mL) suggest specific causes:
  • Lung cancer eroding a pulmonary vessel
  • Bronchiectasis (such as in cystic fibrosis)
  • Cavitary disease (e.g., complicating an aspergilloma or cavitary pulmonary tuberculosis)
  • Pulmonary vasculitis
  • Pulmonary arteriovenous malformation

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6. STRIDOR

• Inspiration lowers pressure inside the extrathoracic trachea → critical narrowing here leads to inspiratory stridor
• The intrathoracic large airways are compressed during expiration by positive pressure → fixed expiratory wheeze or stridor
• Large airway narrowing at the thoracic inlet (e.g., tracheal compression by a large goitre) → both inspiratory and expiratory stridor

Rapid investigation and treatment are vital when this sign is present.

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7. CHEST PAIN

Establish:

• Site and severity
• Character: sharp suggests pleural pain
• Onset: gradual or rapid?
• Exacerbating or relieving factors: worsening with cough or deep breaths → pleural disease
• Associated symptoms: breathlessness, fever and cough → suggest an infective cause

Pleuritic Pain:

• Worse on inspiration and coughing
• Usually described as sharp, stabbing or knife-like
• Sited away from the midline; may be localised or affect a wide area of chest wall

• Pneumonia and pulmonary infarcts: direct pleural inflammation or adhesions with pleural traction on respiratory movement
• Pneumothorax: mechanical distortion of pleura with lung collapse
• Lung cancer: pleural distortion by infiltration, although constant pain is more typical

Musculoskeletal Chest Pain:

• Common; may occur with chest trauma, forceful coughing or connective tissue disease
• Chest is characteristically tender to palpation, and the pain can be reproduced by respiratory movements and/or movement of the spine or shoulder muscles

Special Conditions:

• Bornholm disease (Coxsackie B infection): acute but self-limiting inflammation of intercostal muscles, with episodes of severe unilateral intercostal myalgia lasting a few days
• Costochondritis (Tietze's syndrome): idiopathic inflammation of the costochondral cartilages adjoining the sternum, with acute localised pain and tenderness; eased by simple analgesia
• Herpes zoster (shingles): may start with superficial itch or burning pain in a thoracic dermatome, followed by appearance of a vesicular rash (a 'belt of roses from hell'); pain and altered sensation may persist long after the rash has resolved
• Central, constant, progressive, non-pleuritic chest pain → may represent mediastinal disease, particularly malignancy
• Chest wall pain (without trauma) that is constant, progressive and non-pleuritic → suggests chest wall invasion by malignancy

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8. FEVER, RIGORS AND NIGHT SWEATS

• Infection (acute or chronic) is the usual cause, but lung cancer, lymphoma or vasculitis should also be considered
• Patients use many different terms to describe fever (shivers, chills, shakes) → take care to clarify their actual symptoms
• Rigors are generalised, uncontrollable episodes of vigorous body shaking lasting a few minutes. Despite high fever, the patient may complain of feeling cold and seek extra clothing
• Rigors usually indicate bacterial sepsis; lobar pneumonia and acute pyelonephritis are the most common causes
• Night sweats, particularly if persistent, are associated with chronic infection such as tuberculosis or malignancy, particularly lymphoma
• If patients report having to change nightclothes or sheets frequently due to profuse nocturnal sweating over several weeks → suggests underlying disease

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9. WEIGHT LOSS

• Weight loss also occurs in acute infection with loss of appetite, particularly during hospitalisation
• Ask the patient to estimate the extent and duration of weight loss and enquire about appetite and dietary intake

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10. SLEEPINESS

• Partial obstruction → results in snoring
• Complete collapse → stimulates increased respiratory effort resulting in transient wakening
• Repeated episodes of sleep disturbance cause excessive daytime sleepiness and poor concentration
• OSASH is more common in men; particularly if obese and with a large neck (collar sizes >17 inches) and can be aggravated by alcohol

Ask about:

• Normal sleeping habit: does the patient keep hours that allow reasonable rest?
• Shift or night work: this can disrupt and prevent healthy sleep patterns
• Does the person wake refreshed or exhausted? Sleep apnoea patients are exhausted in the morning
• Have they struggled to stay awake in the day, e.g., at work or when driving?

It is vital to advise cessation of driving pending investigation if OSA is suspected.

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PAST MEDICAL HISTORY

BOX 5.4 — Previous Illness Relevant to Respiratory History

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DRUG AND ALLERGY HISTORY

BOX 5.5 — Respiratory Problems Caused by Drugs

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FAMILY HISTORY

• A family history of venous thromboembolism should prompt investigation of inherited thrombophilias such as Factor V Leiden or protein C or protein S deficiency
• In rare cases, idiopathic pulmonary fibrosis and primary pulmonary hypertension may be familial

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SOCIAL HISTORY

• Passive smoking → increased risk of respiratory infection
• Burning biomass fuels in confined spaces → increased risk of bronchitis and COPD
• Domestic pets, especially cats and rodents → cause of suboptimal asthma control
• A pet bird, feather duvet or an infestation of mould → may cause hypersensitivity pneumonitis or suboptimal asthma control
• Home circumstances may reveal the impact of respiratory disability, e.g., if the patient has relocated to ground-floor accommodations or relies on others for shopping

Smoking

• Cannabis may be smoked without tobacco; e.g., using a bong; or cut with tobacco as an unfiltered joint
• Waterpipes ('narghileh', 'shisha' or 'hookah') are used to smoke tobacco, cannabis or flavoured tobacco (maassel)
• E-cigarettes are used increasingly to assist with smoking cessation

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OCCUPATIONAL HISTORY

BOX 5.6 — Occupational Factors in Respiratory Disease

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SYSTEMATIC ENQUIRY

• Morning headaches → can indicate an elevated PaCO₂ in respiratory failure
• Dysphagia following stroke → can increase the risk of aspiration pneumonia
• Joint pains → may indicate connective tissue disease underlying pleural or parenchymal lung disease

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THE PHYSICAL EXAMINATION

It is often easiest to examine the patient reclining on the bed or an examination couch at about 45 degrees, with the thorax exposed and the head supported by a pillow.

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INSPECTION

• Prolonged expiration relative to inspiration
• Sometimes 'pursed-lip' breathing on expiration
• Forceful inspiration at very high lung volumes may cause indrawing of the intercostal spaces during mid-inspiration
• Recruitment of 'accessory muscles' not normally involved in breathing - the sternocleidomastoid muscles lifting the sternum, and the trapezius and the scalenes lifting the shoulder girdle
• Patients sometimes sit forwards and brace their arms on a surface, allowing them to use the pectoralis major to pull the ribs outwards during inspiration

Chest Deformity:

• Pectus excavatum: congenital inward displacement of the lower ribs with a prominent sternum
• Pectus carinatum: the latter is an inward displacement of the lower ribs with a prominent sternum, caused by severe airflow obstruction in early childhood, during rib cage development
• Asymmetry may be secondary to scoliosis, shrinkage of scarred lung following tuberculosis, or prior surgical resection of the lung and/or ribs

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EXAMINATION SEQUENCE (Boxes 2, 2B and 2C)

General Observation (from end of bed):

• Note the presence of nebulisers or inhalers (indicating obstructive lung disease), oxygen therapy and cyanosis
• Check sputum pots, noting the colour and viscosity of the sputum and whether any blood is present; foul-smelling sputum may indicate anaerobic infection
• Look for asymmetry of the chest, deformities, surgical scars and chest drains, remembering that thoracotomy scars may be visible only from the side or behind
• Quietly observe and time respiratory rate (e.g., breaths in 15 s × 4) without drawing the patient's attention to it, as this may cause it to change
• At rest, the respiratory rate is normally 12 to 15 breaths/min; anxious patients may breathe at 15 to 20 breaths/min but a rate of over 20 breaths/min is abnormal for an adult
• Inspect the remaining skin for relevant abnormalities
• Cheyne-Stokes respiration - a distinctive pattern of alternating periods of deep and shallow breathing - may be seen at high altitude, in elderly people and patients with heart failure, or during the final stages of dying; it is thought to represent abnormal feedback from the carotid chemoreceptors to the respiratory centre

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HANDS AND ARMS

Finger Clubbing

Other Important Signs in the Hands:

• Cyanosis
• Tar staining of fingers from tobacco use
• Small-muscle wasting - may indicate T1 root damage by an apical lung tumour
• Rarely, yellow-brown discolouration of nails in yellow nail syndrome or vasculitis in nail bed or finger pulp

Tremor:

• Fine tremor of the outstretched hands is common in respiratory patients and usually due to the direct effect of high-dose beta-agonist bronchodilators on skeletal muscle
• Coarse flapping tremor (asterixis) of the outstretched hands → respiratory failure with carbon dioxide retention

To test for CO₂ retention tremor: ask the patient to hold their arms out straight with the wrists extended (as shown in Fig. 5.8).

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"Remember that patients do not always report exactly what textbooks describe." — MacLeod's Clinical Examination, Chapter 5

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