RESP

Question 1

Acute respiratory distress syndrome (ARDS) - Definition

Answer 1

Syndrome of acute and persistent lung inflammation with increased vascular permeability. Characterized by:
. acute onset;
. bilateral infiltrates consistent with pulmonary oedema;
. hypoxaemia: PaO2/FiO2 200 mmHg regardless of the level of positive end-expiratory pressure (PEEP);
. no clinical evidence for “ left atrial pressure (pulmonary capillary wedge pressure (PCWP) 18 mmHg).
. ARDS is the severe end of the spectrum of ‘acute lung injury’ (ALI).

Question 2

ARDS - Aetiology

Answer 2

Severe insult to the lungs or other organs induces the release of inflammatory mediators, increased capillary permeability, pulmonary oedema, impaired gas exchange and # lung compliance. Common causes include: sepsis, aspiration, pneumonia, pan- creatitis, trauma/burns, transfusion (massive, transfusion-related lung injury), transplan- tation (bone marrow, lung) and drug overdose/reaction.
Patients progress through three pathologic stages: exudative, proliferative and fibrotic stage.

Question 3

ARDS - History

Answer 3

Rapid deterioration of respiratory function, dyspnoea, respiratory distress, cough, symptoms of aetiology.

Question 4

ARDS - Examination

Answer 4

Cyanosis, tachypnoea, tachycardia, widespread inspiratory crepitations. Hypoxia refractory to oxygen treatment.
Signs are usually bilateral but may be asymmetrical in early stages.

Question 5

ARDS - Investigations

Answer 5

CXR: Bilateral alveolar and interstitial shadowing.
Blood: FBC, U&E, LFT, ESR/CRP, amylase, clotting, ABG, blood culture, sputum culture. Plasma BNP < 100 pg/mL may distinguish ARDS/ALI from heart failure, but higher levels can
neither confirm heart failure nor exclude ARDS/ALI in critically ill patients. Echocardiography: Severe aortic or mitral valve dysfunction or low LVEF favours haemodynamic oedema over ARDS.
Pulmonary artery catheterization: PCWP 18 mmHg (however high PCWP does not exclude
ARDS as patients with ARDS may have concomitant left ventricular dysfunction). Bronchoscopy: If the cause cannot be determined from the history, and to exclude differentials, e.g. diffuse alveolar haemorrhage (frothy blood in all airways, haemosider- in-laden macrophage from lavage fluid), lavage fluid for microbiology (mycobacteria, Legionella pneumophila, Pneumocystis, respiratory viruses) and cytology (eosinophils,
viral inclusion bodies and cancer cells).

Question 6

ARDS - Management

Answer 6

Respiratory support: Supplemental oxygen (FiO2: 50–60%). Almost all patients require intubation and mechanical ventilation.
Fully supported volume limited and pressure limited modes are both acceptable. The tidal volume, respiratory rate, PEEP and FiO2 are managed according to the strategy of low tidal volume ventilation (LTVV). The rationale for LTVV is that smaller tidal volumes are less likely to generate alveolar overdistension and ventilator-associated lung injury. LTVV frequently requires ‘permissive hypercapnic ventilation’, a ventilatory strategy that accepts alveolar hypoventilation in order to maintain a low alveolar pressure and minimize the complications of alveolar overdistension. The lowest plateau airway pressure possible should be targeted.
Sedation and analgesia: To improve tolerance of mechanical ventilation and to less oxygen consumption. Neuromuscular blockade should be used only when sedation alone is inadequate.

Fluid management: Conservative strategy, as long as hypotension and organ hypoperfu- sion can be avoided (target a central venous pressure of <4 mmHg), blood transfusion if Hb < 7 g/dL, no evidence for inotropes cardiac function is normal.
Nutritional support: Enteral feedings are preferred, control of blood glucose.
Treat the cause: e.g. antibiotics for sepsis.
Prophylaxis/treat complications: e.g. nosocomial pneumonia, deep vein thrombosis
(DVT) and gastrointestinal bleeding.
C O M P L I C A T I O N S Respiratory failure, death. Complications related to mechanical ven- tilation, e.g. barotraumas (pneumothorax, subcutaneous emphysema) or intensive care (nosocomial pneumonia).
P R O G N O S I S Highly variable depending on cause but generally poor. Mortality 60% (mostly from sepsis). “ Mortality with “ age, sepsis and steroid treatment prior to the onset of ARDS. ARDS associated with trauma has a lower mortality.

Question 7

Aspergillus lung disease - Definition

Answer 7

Lung disease associated with Aspergillus fungal infection.

Question 8

Aspergillus lung disease - Aetiology

Answer 8

Inhalation of the ubiquitous Aspergillus (usually Aspergillus fumigates) spores can produce three different clinical pictures:
1.Aspergilloma: Growth of an A.fumigatus mycetoma ball in a preexisting lung cavity(e.g. post-TB, old infarct or abscess).
2. Allergic bronchopulmonary aspergillosis (ABPA): Aspergillus colonization of the airways (usually in asthmatics) leads to IgE- and IgG-mediated immune responses. Proteolytic enzymes and mycotoxins released by fungi, CD4/Th2 cells producing IL-4 and IL-5 and mediating eosinophilic inflammation, and IL-8 mediated neutrophilic inflamma- tion result in airway damage and central bronchiectasis.
Invasive aspergillosis: Invasion of Aspergillus into lung tissue and fungal dissemination. Secondary to immunosuppression (e.g. neutropaenia, steroids, haematopoietic stem cell/ solid organ transplantation, AIDS).

Question 9

Aspergillus lung disease - History

Answer 9

Aspergilloma: Asymptomatic, haemoptysis, which may be massive.
ABPA: Difficult to control asthma, recurrent episodes of pneumonia with wheeze, cough,
fever and malaise.
Invasive aspergillosis: Dyspnoea, rapid deterioration, septic picture.

Question 10

Aspergillus lung disease - Examination

Answer 10

Tracheal deviation in large aspergillomas. Dullness in affected lung, decreased breath sounds, wheeze (in ABPA). Cyanosis may develop in invasive aspergillosis.

Question 11

Aspergillus lung disease - Investigation

Answer 11

Aspergilloma: CXR: Round opacity may be seen with a crescent of air around it (usually in the upper lobes).
CT or MR imaging if CXR does not clearly delineate a cavity.
Cultures of the sputum may be negative if there is no communication between the cavity and
the bronchial tree. Also Aspergillus is a common colonizer of an abnormal respiratory
tract.

ABPA:
Immediate skin test reactivity to Aspergillus antigens.
Eosinophilia.
- high Serum total IgE.
- high Serum specific IgE and IgG to A. fumigatus or precipitating serum antibodies to A.
fumigates.
CXR: Transient patchy shadows, collapse, distended mucus-filled bronchi producing tubular
shadows (‘gloved fingers’ appearance). Signs of complications: Fibrosis in upper lobes
(similar to tuberculosis), parallel-line shadows and rings (bronchiectasis).
CT: Lung infiltrates, central bronchiectasis.
Lung function tests: Reversible airflow limitation, decreased lung volumes/gas transfer in progressive
cases.

Invasive aspergillosis: Detection of Aspergillus in cultures or by histologic examination
(septated hyphae with acute angle branching). Diagnosis may be made in patients with risk factors, suggestive clinical findings and microscopic evidence of septate hyphae on examination of either bronchoalveolar lavage fluid or sputum or a positive serum galactomannan or beta-D-glucan assay (constituents of Aspergillus cell walls).
Chest CT scan may show nodules surrounded by a ground-glass appearance (halo sign) in invasive pulmonary aspergillosis (haemorrhage into the tissue surrounding the area of fungal invasion).

Question 12

Aspergillus lung disease - Management

Answer 12

Aspergilloma: Surgical resection for large aspergillomas if uncontrolled or symptomatic
(recurrent haemoptysis). Adjunctive itraconazole or voriconazole, if there is concern for
residual disease following surgery, or tissue invasion beyond the confines of the cavity. ABPA: Combination of steroids and itraconazole. Monitor LFTs. The usual duration of therapy is 3–6 months. Inhaled steroids and broncholdilators may help control symptoms of asthma. The response is monitored with serial measurement of the serum total IgE level. Invasive aspergillosis: decrease Immunosuppression if possible. Voriconazole (initially IV, when stabilized orally). Monitor serum voriconazole trough concentrations. If intolerant of voriconazole, use liposomal amphotericin B. Add caspofungin in patients who do not respond. Continue antifungal therapy until all signs, symptoms and radiographic evi- dence of the infection have resolved for at least 2 weeks. Debridement is essential in the
treatment of Aspergillus sinusitis.
COMPLICATIONS
Aspergilloma: Secondary bacterial infection, massive haemoptysis or haemorrhage. ABPA: Worsening of asthma, bronchiectasis, lobar collapse, lung fibrosis or respiratory
failure.
Invasive aspergillosis: Septic shock, respiratory failure.
P R O G N O S I S Grave prognosis for invasive aspergillosis. Good prognosis for ABPA and aspergillomas but bronchospasm and haemoptysis can still lead to death.

Question 13

Asthma - Definition

Answer 13

Chronic inflammatory airway disease characterized by variable reversible airway obstruction, airway hyper-responsiveness and bronchial inflammation.

Question 14

Asthma - Aetiology

Answer 14

Genetic factors: Positive family history, twin studies. Almost all asthmatic patients show some atopy (tendency of T lymphocyte (Th2) cells to drive production of IgE on exposure to allergens). Linkages to multiple chromosomal locations point to ‘genetic heterogeneity’.
Environmental factors: House dust mite, pollen, pets (e.g. urinary proteins, furs), cigarette smoke, viral respiratory tract infection, Aspergillus fumigatus spores, occupational allergens (isocyanates, epoxy resins).
PATHOLOGY/PATHOGENESIS
Early phase (up to 1 h): Exposure to inhaled allergens in a presensitized individual results in cross-linking of IgE antibodies on the mast cell surface and release of histamine, prostaglandin D2, leukotrienes and TNF-a. These mediators induce smooth muscle contraction (bronchoconstriction), mucous hypersecretion, oedema and airway obstruction.
Late phase (after 6–12h): Recruitment of eosinophils, basophils, neutrophil and Th2 lymphocytes and their products results in perpetuation of the inflammation and bronchial hyper-responsiveness.
Structural cells (bronchial epithelial cells, fibroblasts, smooth muscle and vascular endothelial cells), may also release cytokines, profibrogenic and proliferative growth factors, and contribute to the inflammation and altered function and proliferation of smooth muscle cells and fibroblasts (‘airway remodeling’).

Question 15

Asthma - History

Answer 15

Episodes of wheeze, breathlessness, cough; worse in the morning and at night. Ask about interference with exercise, sleeping, days off school and work.
In an acute attack it is important to ask whether the patient has been admitted to hospital because of his/her asthma, or to ITU, as a gauge of potential severity.
Precipitating factors: Cold, viral infection, drugs (b-blockers, NSAIDs), exercise, emotions. May have a history of allergic rhinitis, urticaria, eczema, nasal polyps, acid reflux and family
history.

Question 16

Asthma - Examination

Answer 16

Tachypnoea, use of accessory muscles, prolonged expiratory phase, polyphonic wheeze, hyperinflated chest.
Severe attack: PEFR < 50% predicted, pulse > 110/min, respiratory rate > 25/min, inability to complete sentences.
Life-threatening attack: PEFR<33%, silent chest, cyanosis, bradycardia, hypotension, confusion, coma.

Question 17

Asthma - Investigations

Answer 17

Acute: Peak flow, pulse oximetry, ABG, CXR (to exclude other diagnoses, e.g. pneumotho- rax, pneumonia), FBC (“ WCC if infective exacerbation), CRP, U&Es, blood and sputum cultures.
Chronic: PEFR monitoring: There is often a diurnal variation with a morning ‘dip’. Pulmonary function test: Obstructive defect, with improvement after a trial of a b2-agonist. Blood: Eosinophilia, IgE level, Aspergillus antibody titres (see allergic Aspergillus lung disease). Skin prick tests: May help in the identification of allergens.

Question 18

Asthma - Management

Answer 18

Acute:
. Resuscitate, monitor O2 sats, ABG and PEFR.
. High-flow oxygen.
. Nebulized b2-agonist bronchodilator salbutamol (5 mg, initially continuously, then 2–4 hourly), ipratropium (0.5 mg qds).
. Steroid therapy (100–200 mg IV hydrocortisone, followed by 40 mg oral prednisolone for 5–7 days).
. If no improvement: IV magnesium sulphate. Consider IV aminophylline infusion or IV salbutamol.
. Summon anaesthetic help if patient is getting exhausted (PCO2 increasing).
Treat any underlying cause (e.g. infection, pneumothorax). Give antibiotics if there is evidence of chest infection (purulent sputum, abnormal CXR, increased WCC, fever). Monitor electrolytes closely (bronchodilators and aminophyline low K + ).
. May need ventilation in severe attacks. If not improving or patient tiring, involve ITU early.
Discharge: When PEF > 75% predicted or patient’s best, diurnal variation < 25%, inhaler technique checked, stable on discharge medication for 24 h, patient owns a PEF meter and has steroid and bronchodilator therapy. Arrange follow-up.
Chronic ‘stepwise’ therapy: Start on the step appropriate to initial severity and step up or down to control symptoms. Treatment should be reviewed every 3–6 months.
Step 1: Inhaled short-acting b2-agonist as needed. If used >1/day, move to Step 2.
Step 2: As Step 1 plus regular inhaled low-dose steroids (400 mcg/day).
Step 3: As Step 2 plus inhaled long-acting b2-agonist (LABA). If inadequate control with LABA,
“ steroid dose (800 mcg/day). If no response to LABA, stop and “ steroid dose (800 mcg/
day).
Step 4: “ Inhaled steroid dose (2000 mcg/day), add a fourth drug, e.g. leukotriene receptor
antagonist, SR theophylline or b2-agonist tablet.
Step 5: Addition of regular oral steroids. Maintain high-dose inhaled steroid. Consider other
treatments to minimize the use of oral steroids. Refer for specialist care.
Advice: Educate on proper inhaler technique and routine monitoring of peak flow. Develop an individualized management plan, with emphasis on avoidance of provoking factors.
C O M P L I C A T I O N S Growth retardation, chest wall deformity (e.g. pigeon chest), recurrent infections, pneumothorax, respiratory failure, death.
P R O G N O S I S Many children improve as they grow older. Adult-onset asthma is usually chronic.

Question 19

Bronchiectasis - Definition

Answer 19

Lung airway disease characterized by chronic bronchial dilation, impaired mucuociliary clearance and frequent bacterial infections.

Question 20

Bronchiectasis - Aetiology

Answer 20

Severe inflammation in the lung causes fibrosis and dilation of the bronchi. This is followed by pooling of mucus, predisposing to further cycles of infection, damage and fibrosis to bronchial walls.
. Causes of bronchiectasis.
. Idiopathic in 50% of cases.
. Post-infectious: After severe pneumonia, whooping cough, tuberculosis.
Host defence defects: e.g. Kartagener’s syndrome,1 cystic fibrosis, immunoglobulin defi- ciency, yellow-nail syndrome.2
. Obstruction of bronchi: Foreign body, enlarged lymph nodes.
. Gastric reflux disease.
. Inflammatory disorders: e.g. rheumatoid arthritis.

Question 21

Bronchiectasis - History

Answer 21

Productive cough with purulent sputum or haemoptysis. Breathlessness, chest pain, malaise, fever, weight loss.
Symptoms usually begin after an acute respiratory illness.

Question 22

Bronchiectasis - Examination

Answer 22

Finger clubbing; Coarse creptitations (usually at the bases) which shift with coughing; Wheeze.

Question 23

Bronchiectasis - Investigations

Answer 23

Sputum: Culture and sensitivity, common organisms in acute exacerbations: Pseudomonas aeruginosa, Haemophilus influenzae, Staphylococcus aureus, Streptococcus pneumo- niae, Klebsiella, Moraxella catarrhalis, Mycobacteria.
CXR: Dilated bronchi may be seen as parallel lines radiating from hilum to the diaphragm (‘tramline shadows’). It may also show fibrosis, atelectasis, pneumonic consolidations, or it may be normal.
High-resolution CT: Dilated bronchi with thickened walls. Best diagnostic method. Bronchography (rarely used): To determine extent of disease before surgery (radio-
opaque contrast injected through the cricoid ligament or via a bronchoscope).
Other: Sweat electrolytes (see Cystic fibrosis), serum immunoglobulins ( 10% of adults have some immune deficiency), sinus X-ray (30% have concomitant rhinosinusitis), mucociliary
clearance study.

Question 24

Bronchiectasis - Management

Answer 24

Treat acute exacerbations with two IV antibiotics with efficacy for Pseudomonas. Prophylactic courses of antibiotics (oral or aerosolized) for those with frequent ( 3/year) exacerbations.
Inhaled corticosteroids (e.g. fluticasone) have been shown to reduce inflammation and volume of sputum, although it does not affect the frequency of exacerbations or lung function.
Bronchodilators may be considered in patients with responsive disease. Maintain hydration with adequate oral fluid intake.Consider flu vaccination.
Physiotherapy: Cornerstone of management is sputum and mucus clearance techniques (e.g.
postural drainage). Patients are taught to position themselves so the lobe to be drained is uppermost, 20min twice daily. Some studies show that these techniques reduce frequency of acute exacerbations and aids recovery.
Bronchial artery embolization: For life-threatening haemoptysis due to bronchiectasis. Surgical: Various surgical options include localized resection, lung or heart–lung
transplantation.
C O M P L I C A T I O N S Life-threatening haemoptysis, persistent infections, empyema, respi- ratory failure, cor pulmonale, multi-organ abscesses.
P R O G N O S I S Most patients continue to have the symptoms after 10 years.

Question 25

Chronic obstructive pulmonary disease (COPD) - Definition

Answer 25

Chronic, progressive lung disorder characterized by airflow obstruction, with the following.
Chronic bronchitis: Chronic cough and sputum production on most days for at least 3 months per year over 2 consecutive years; and/or
Emphysema: Pathological diagnosis of permanent destructive enlargement of air spaces distal to the terminal bronchioles.

Question 26

COPD - Aetiology

Answer 26

Bronchial and alveolar damage as a result of environmental toxins (e.g. cigarette smoke). A rare cause is a1-antitrypsin deficiency (<1%) but should be consid- ered in young patients or in those who have never smoked. Overlaps and may co-present with asthma.
Chronic bronchitis: Narrowing of the airways resulting from bronchiole inflammation (bronchiolitis) and bronchi with mucosal oedema, mucous hypersecretion and squamous metaplasia.
Emphysema: Destruction and enlargement of the alveoli. This results in loss of the elastic traction that keeps small airways open in expiration. Progressively larger spaces develop, termed bullae (diameter is >1 cm).

Question 27

COPD - History

Answer 27

Chronic cough and sputum production (see Definition). Breathlessness, wheeze, decreased exercise tolerance.

Question 28

COPD - Examination

Answer 28

Inspection: May have respiratory distress, use of accessory muscles, barrel-shaped overin- flated chest, less cricosternal distance, cyanosis.
Percussion: Hyper-resonant chest, loss of liver and cardiac dullness.
Auscultation: Quiet breath sounds, prolonged expiration, wheeze, rhonchi and crepitations
sometimes present.
Signs of CO2retention: Bounding pulse, warm peripheries, flapping tremor of the hands
(asterixis). In late stages, signs of right heart failure (e.g. right ventricular heave, raised JVP, ankle oedema).

Question 29

COPD - Investigations

Answer 29

Spirometry and pulmonary function tests: Obstructive picture as reflected by # PEFR, # FEV1: FVC ratio (mild, 60–80%; moderate, 40–60%; severe, <40%), “ lung volumes and carbon monoxide gas transfer coefficient # when significant alveolar destruction.
CXR: May appear normal or show hyperinflation (>6 ribs visible anteriorly, flat hemi- diaphragms), # peripheral lung markings, elongated cardiac silhouette.
Blood: FBC (“ Hb and PCV as a result of secondary polycythemia).
ABG: May show hypoxia (# PaO2), normal or “ PaCO2.
ECG and echocardiogram: For cor pulmonale (see Cardiac failure).
Sputum and blood cultures: In acute exacerbations for treatment.
Consider a1-antitrypsin levels in young patients or minimal smoking history.

Question 30

COPD - Management

Answer 30

Stop smoking.
Bronchodilators: Short-acting b2-agonists (e.g. salbutamol) and anticholinergics (e.g. ipra-
tropium), delivered by inhalers or nebulizers. Long-acting bronchodilators should be used
if >2 exacerbations per year.
Steroids: Inhaled beclometasone should be considered for all with FEV1 <50% predicted or
those with >2 exacerbations per year. Regular oral steroids should be avoided but may be necessary for maintenance.
Pulmonary rehabilitation.
Oxygen therapy (only for those who stop smoking): Long-term home oxygen therapy has
been shown to improve mortality. Indications are:
. PaO2 < 7.3 kPa on air during a period of clinical stability.
. PaO2 7.3–8.0 kPa and signs of secondary polycythaemia, nocturnal hypoxaemia, periph-
eral oedema or pulmonary hypertension.
Oxygen concentrators are more economical if being used for >8 h/day. Treatment of acute infective exacerbations:
Provide 24% O2 via non-variable flow Venturi mask.
Increase slowly if no hypercapnia and still hypoxic (measured by ABG). Corticosteroids (oral or inhaled) are of proven benefit.
Start empirical antibiotic therapy (follow local policy) if evidence of infection. Respiratory physiotherapy is essential to clear sputum.
Consider non-invasive ventilation in severe cases.
Prevention of infective exacerbations: Pneumococcal and influenza vaccination.

C O M P L I C A T I O N S: Acute respiratory failure, infections (particularly Streptococcus pneu- moniae, Haemophilus influenzae), pulmonary hypertension and right heart failure, pneu- mothorax (resulting from bullae rupture), secondary polycythaemia.
P R O G N O S I S High level of morbidity. Three-year survival rate of 90% if age <60 years and FEV1 >50% predicted; 75% if >60 years and FEV1 40–49% predicted.

Question 31

Cystic Fibrosis - Definition

Answer 31

Autosomal recessive inherited multi-system disease characterized by recurrent respiratory tract infections, pancreatic insufficiency, malabsorption and male infertility.

Question 32

Cystic Fibrosis - Aetiology

Answer 32

Caused by a defective CFTR gene on chromosome 7q, which encodes a cAMP-dependent Cl channel. This channel regulates Naþ and Cl concentrations in exocrine secretions, especially in the lung and pancreas. Any loss of function mutations results in thick viscous secretions. Greater than 800 mutations reported, most common is DF508 phenylalanine deletion (75% cases in UK).
At birth, the lung is normal histologically but as the lung matures there is mucous gland hyperplasia, recurrent infection leads to fibrosis, consolidation and bronchiectasis.

Question 33

Cystic Fibrosis - History

Answer 33

Lung: Recurrent chest infections, chronic cough, wheeze, sputum, haemoptysis. Gut: Meconium ileus (in neonates), steatorrhoea (caused by “ fat in the stool). Other: Chronic sinusitis, nasal polyps, male infertility, arthritis.

Question 34

Cystic Fibrosis - Examination

Answer 34

Chest: Chest wall deformities, coarse crepitations and wheeze.
Signs of malnutrition: Anaemia, weight loss, signs of vitamin deficiencies, slow growth,
failure to thrive in children, delayed puberty in adolescents. Other: Clubbing, nasal polyps, signs of diabetes, hepatomegaly.

Question 35

Cystic Fibrosis - Investigations

Answer 35

Sweat test: Pilocarpine iontophoresis (low electrical current) stimulates sweat secretion which is collected and analyzed for Na þ and Cl (Cl levels >60 mmol is diagnostic of cystic fibrosis).
Neonatal screening: Standard day 6 Guthrie heal prick, blood is tested for immunoreactive trypsin (raised by 2–5 in babies with cystic fibrosis).
CXR: May be normal in mild disease or show increased bronchial markings, ring shadows, fibrosis (often upper zone). Consolidation or bronchiectasis in more advanced cases.
Pancreatic assessment: Faecal elastase, faecal fat content, GTT, HbA1c. Genetic analysis: For CFTR mutations. Rarely necessary.
Lung function tests: To assess lung function and for long-term prognosis.

Question 36

Cystic Fibrosis - Management

Answer 36

Multidisciplinary specialist care is necessary. Respiratory:
. Chest physiotherapy (postural drainage, regular exercise), positive expiratory pressure masks;
. bronchodilator therapy (if responsive);
. nebulized recombinant human deoxyribonuclease (rhDNase) and hypertonic saline can be
used to assist in mucociliary clearance and may reduce pulmonary exarcebations;
. antibiotic prophylaxis and aggressive treatment of infections (especially Pseudomonas);
. influenza vaccination.
GI: Adequate nutritional intake is vital, using high-calorie oral supplements and oral pancreatic enzyme replacement, vitamin (especially fat-soluble) supplements.
Endocrine: Insulin replacement therapy if diabetes develops.
Surgical: Single lung or heart–lung transplants is an option in end-stage disease (5-year
survival is 55%).
C O M P L I C A T I O N S Recurrent chest infections, bronchiectasis (particularly Haemophilus, Staphylococcus and Pseudomonas).
Malabsorption, meconium ileus, intussusception, rectal prolapse. Diabetes mellitus Type I (30% by late teens).
Male infertility (females are fertile but conception may be difficult). Gallstones.
P R O G N O S I S Life expectancy is in the third decade, but steadily improving. Those with pancreatic insufficiency and those colonized by Pseudomonas have poorer prognosis. Gene replacement therapy may be possible in the future.

Question 37

Extrinsic allergic alveolitis - Definition

Answer 37

Interstitial inflammatory disease of the distal gas-exchanging parts of the lung caused by inhalation of organic dusts. Also known as hypersensitivity pneumonitis.

Question 38

Extrinsic allergic alveolitis - Aetiology

Answer 38

Inhalation of antigenic organic dusts containing microbes (bacteria, fungi or amoebae) or animal proteins induce a hypersensitivity response (a combination of type III antigen–antibody complex hypersensitivity reaction and a type IV granulomatous lym- phocytic inflammation) in susceptible individuals. Examples:
Farmer’s lung: Mouldy hay containing thermophilic actinomycetes. Pigeon/budgerigar fancier’s lung: Bloom on bird feathers and excreta. Mushroom worker’s lung: Compost containing thermophilic actinomycetes. Humidifier lung: Water-containing bacteria and Naegleria (amoeba). Maltworker’s lung: Barley or maltings containing Aspergillus clavatus.

Question 39

Extrinsic allergic alveolitis - History

Answer 39

Acute: Presents 4–12 h post-exposure. Reversible episodes of dry cough, dyspnoea, malaise, fever, myalgia. Wheeze and productive cough may develop on repeat high-level exposures.
Chronic: Poorly reversible manifestation in some, slowly “ breathlessness and # exercise tolerance, weight loss. Exposure is usually chronic, low level and there may be no history of previous acute episodes.
Full occupational history and enquiry into hobbies and pets important.

Question 40

Extrinsic allergic alveolitis - Examination

Answer 40

Acute: Rapid shallow breathing, pyrexia, inspiratory crepitations.
Chronic: Fine inspiratory crepitations (see Cryptogenic fibrosing alveolitis). Finger clubbing
is rare.

Question 41

Extrinsic allergic alveolitis - Investigations

Answer 41

Blood: FBC (neutrophilia, lymphopenia), ABG (# PO2, # PCO2).
Serology: Precipitating IgG to fungal or avian antigens in serum; however, these are not
diagnostic as are often found in asymptomatic individuals.
CXR: Often normal in acute episodes, may show ‘ground glass’ appearance with alveolar
shadowing or nodular opacities in the middle and lower zones. In chronic cases, fibrosis is
prominent in the upper zones.
High-resolution CT-thorax: Detects early changes before CXR. Patchy ‘ground glass’
shadowing and nodules.
Pulmonary function tests: Restrictive ventilatory defect (# FEV1, # FVC with preserved or
increased ratio), # TLCO.
Bronchoalveolar lavage: Increased cellularity with “ CD8 þ suppressor T cells. Lung biopsy
(transbronchial or thorascopic).

Question 42

Extrinsic allergic alveolitis - Management

Answer 42

Advice: Complete avoidance of exposure to the antigen (e.g. change of work practice or hobby), if this is problematic, then minimize exposure and encourage use of respiratory protection masks.
Medical:
Acute flare: Spontaneous recovery usually within 1–2 days, high-dose corticosteroids for 2–4 weeks may accelerate recovery but do not appear to affect long-term outcome.
Chronic disease: Trial of high-dose oral prednisolone for 1 month may be carried out, this is gradually reduced, or stopped if no objective response demonstrated.General: Regular follow-up to monitor lung function. Environmental assessment is necessary for risk posed to others. In UK, farmer’s lung patients are entitled to compensation, depending on the degree of disability.

C O M P L I C A T I O N S: Progressive lung fibrosis, pulmonary hypertension, right heart failure.

P R O G N O S I S: The acute form generally resolves if further exposure is prevented, with chronic disease some patients will improve while a minority progress to lung fibrosis.

Question 43

Idiopathic fibrosing alveolitis - Definition

Answer 43

Inflammatory condition of the lung resulting in fibrosis of alveoli and interstitium. Previously known as ‘cryptogenic fibrosing alveolitis’.

Question 44

Aetiology

Answer 44

In a genetically predisposed host (e.g. with telomerase/surfactant protein mutations), recurrent injury to alveolar epithelial cells may result in secretion of cytokines and growth factors (e.g. TNF-a, IL-1 and MCP-1) which cause fibroblast activation, recruitment, proliferation, differentiation into myofibroblasts and “ collagen synthesis and deposition. Profibrogenic molecules, e.g. PDGF and TGF-b, are secreted by inflam- matory, epithelial and endothelial cells.
Certain drugs can produce a similar illness (e.g. bleomycin, methotrexate and amiodarone). Histological patterns: Usual interstitial pneumonia (UIP: patchy interstitial fibrosis, later: ‘honeycomb’ lung). Desquamative interstitial pneumonia (DIP: diffuse intra-alveolar accumulation of macrophages, mild thickening of alveolar septa, lymphoid aggregates)
and non-specific interstitial pneumonia (NSIP).
Risk factors: Smoking (in 75%), occupational exposure to metal (steel, brass, lead) or wood
(pine) in 20% cases; chronic microaspiration, animal and vegetable dusts.

Question 45

History

Answer 45

Gradual onset of progressive dyspnoea on exertion. Dry irritating cough. No wheeze.
Symptoms may be preceded by a viral-type illness.
Fatigue and weight loss are common.
Full occupational and drug history is important.

Question 46

Examination

Answer 46

Finger clubbing ( 50%).
Bibasal fine late inspiratory crepitations.
Signs of right heart failure in advanced stages (e.g. right ventricular heave, raised JVP, peripheral oedema).

Question 47

Investigations

Answer 47

Blood: ABG (normal in early disease, but # PO2 on exercise; normal PCO2 which rises in late disease). One-third have rheumatoid factor or antinuclear antibodies.
CXR: Usually normal at presentation. Early disease may feature small lung fields and ‘ground glass’ shadowing. Later, there is reticulonodular shadowing (especially at bases), signs of cor pulmonale and eventually, in advanced disease, honeycombing.
High-resolution CT: More sensitive in early disease than CXR. Affecting mainly lower zones and subpleural areas, with reticular densities, honeycombing and traction bronchiectasis. Pulmonary function tests: Restrictive ventilatory defect (# FEV1, # FVC with preserved or
increased ratio), # lung volumes, # lung compliance and # TLCO. Bronchoalveolar lavage: To exclude infections and malignancy. Lung biopsy: Gold standard for diagnosis but may not be appropriate. Echocardiography: To look for pulmonary hypertension.

Question 48

Management

Answer 48

No curative treatment available.
Combination of azathioprine, oral glucocorticoids and high-dose acetylcysteine, reassess the
response (symptoms, lung function tests) every 3 months. After 3–6 months of treatment, if there is no evidence of a response, treatment is discontinued. Immunosuppressant therapy may not be offered to patients with severe loss of lung function or extensive fibrosis on high-resolution chest CT.
Supportive care: Home oxygen may be necessary. Pulmonary rehabilitation. Opiates in terminal stages for relieving distressing breathlessness. Psychosocial support is necessary because of poor long-term prognosis.
Acute exacerbation: Broad-spectrum antibiotics and high-dose glucocorticoids.

Surgical: Single lung transplantation. Lung transplantation may be an option for patients with progressive disease and minimal comorbidities.

C O M P L I C A T I O N S:
Right heart failure. Lung cancer (12%). Pulmonary embolus. Death from respiratory failure.
P R O G N O S I S:
Poor; mean survival is only about 3 years. Good prognostic factors: Clinical: Young age, female, response to steroids.
Radiological: Predominantly ‘ground glass’ shadowing.
Histology: DIP and NSIP better response to treatment than UIP.

Question 49

Lung cancer, non-small cell - Definition

Answer 49

Primary malignant neoplasm of the lung. WHO classification of broncho- carcinoma: Small cell (20%; see separate topic) and non-small cell (80%).
Histological types of non-small cell lung cancer include: Squamous cell carcinoma, adeno- carcinoma, large cell carcinoma and adenosquamous carcinoma.

Question 50

Lung cancer, non-small cell - Aetiology

Answer 50

Factors such as smoking (active or passive) are thought to ultimately cause genetic alterations that result in neoplastic transformation. Other risk factors include occupational exposures (polycyclic hydrocarbons, asbestos, nickel, chromium, cadmium, radon) and atmospheric pollution.
Tumours generally arise in main or lobar bronchi. Adenocarcinomas tend to occur more peripherally.

Question 51

Lung cancer, non-small cell - History

Answer 51

May be asymptomatic with radiographic abnormality found (5%).
Due to primary: Cough, haemoptysis, chest pain, recurrent pneumonia.
Due to local invasion: e.g. brachial plexus (Pancoast tumour, in the apex of the lung) causing
pain in the shoulder or arm, left recurrent laryngeal nerve (hoarseness and bovine cough),
oesophagus (dysphagia), heart (palpitations/arrhythmias).
Due to metastatic disease or paraneoplastic phenomena: Weight loss, fatigue, fits, bone pain
or fractures, neuromyopathies.

Question 52

Lung cancer, non-small cell - Examination

Answer 52

There may be no signs. Fixed monophonic wheeze. Signs of collapse, consolidation or pleural effusion.
Due to local invasion: Superior vena cava compression (facial congestion, distension of neck veins, upper limb oedema). Brachial plexus (wasting of the small muscles of the hand). Sympathetic chain (Horner’s syndrome: pupillary miosis, ptosis and facial anhydrosis).
Due to paraneoplastic phenomena: Hypertrophic osteoarthropathy: clubbing, painful swollen wrists/ankles (periosteal new bone formation). Dermatological signs (see Complications).
Due to metastases: Supraclavicular lymphadenopathy, hepatomegaly.

Question 53

Lung cancer, non-small cell - Investigations

Answer 53

Diagnosis: CXR (coin lesions, lobar collapse, pleural effusion, features of lymphangitis carcinomatosis1). Sputum cytology, bronchoscopy with brushings or biopsy, CT- or ultrasound-guided percutaneous biopsy, lymph node biopsy.
TNM staging: Based on tumour size, nodal involvement and metastatic spread, using CT chest, CT or MRI head and abdomen (or ultrasound), bone scan, PET scan. Invasive methods like mediastinoscopy or video-assisted thoracoscopy may be used.
Bloods:FBC,U&Es,Ca2þ (hypercalcaemiaiscommon),AlkPhos(“bonemetastases),LFT. Pre-op: ABG, pulmonary function tests (FEV1 > 80% predicted to tolerate a pneumonecto- my, lung resection is contraindicated if FEV1 < 30% predicted), V/Q scan, ECG, echo-
cardiogram and general anaesthetic assessment.

Question 54

Lung cancer, non-small cell - Management

Answer 54

Multidisciplinary discussion on tumour staging and optimal treatment modality. Important considerations are resectibility of the tumour (stages I and II disease, selectively IIIa) and operability (whether a patient is fit enough to undergo surgery). Frank discussion with the patient about the risks/benefits and the prognosis is vital. Only 14% cases are considered for surgery.
Surgery: Aimed at curative resection but often not appropriate.
Non-operable: Combined modality therapy with radiotherapy and chemotherapy improves
survival. Docetaxel is a commonly used chemotherapy. Biological therapy in the form of erlotinib (epidermal growth factor receptor, EGFR, tyrosine kinase inhibitor) is a second- line chemotherapy agent.
Palliation and terminal care: Includes laser therapy to bronchial tumours, endobronchial stents, management of complications and pain control.
COMPLICATION Local invasion. Metastases (commonly liver, bones, brain, adrenals). Pneumonia, pleural effusion, lung collapse. Paraneoplastic syndromes (squamous cell car- cinomas are associated with hypercalcaemia of malignancy). Skin: Acanthosis nigricans (pigmented thickened skin in axilla or neck), herpes zoster, dermatomyositis, thrombophle- bitis migrans.
P R O G N O S I S Depends on stage, but generally poor. Overall 5-year survival <5%. After resection for early stage disease 25% 5-year survival. Mortality of lobectomy is <2%, and mortality for pneumonectomy is 8%.

Question 55

Lung Cancer, small cell - Definition

Answer 55

Malignant neoplasm of neuroendocrine Kulchitsky cells of the lung with early dissemination. Also known as oat cell carcinoma.

Question 56

Lung Cancer, small cell - Aetiology

Answer 56

Smoking. Occupational and environmental exposures (see Lung cancer, non- small cell).

Question 57

Lung Cancer, small cell - History

Answer 57

May be asymptomatic with radiographical abnormality found.
Due to primary tumour: Cough, haemoptysis, dyspnoea, chest pain.
Due to metastatic disease: Weight loss, fatigue, bone pain.
Due to paraneoplastic syndromes: Weakness, lethargy, seizures, muscle fatiguability.

Question 58

Lung Cancer, small cell - Examination

Answer 58

May be no signs or a fixed wheeze on auscultation of the chest. Signs of lobar collapse or pleural effusion.
Signs of metastases, e.g. supraclavicular lymphadenopathy or hepatomegaly.
Signs of paraneoplastic syndrome.

Question 59

Lung Cancer, small cell - Investigations

Answer 59

Diagnosis: Sputum cytology, bronchoscopy with brushings and biopsy or percutaneous biopsy, thoracoscopy.
Staging: CT of chest, abdomen, head. Isotope bone scan. Other: Lung function tests, FBC, U&E, Ca2 þ , AlkPhos, LFT.

Question 60

Lung Cancer, small cell - Management

Answer 60

Limited disease: Combination chemotherapy and radiotherapy. Cisplatin and etoposide is a common regimen and chest irradiation results in a 5% improvement in 3-year survival. Prophylactic cranial irradiation also improves survival in those who achieve a complete remission or have limited stage disease.
Extensive disease: Chemotherapy, e.g. cisplatin and etoposide. Palliation: Radiotherapy to metastasis.
C O M P L I C A T I O N S Pneumonia, superior vena caval compression.
Metastases: Most commonly to brain, liver, adrenals, skin.
Endocrine: Ectopic ACTH (1%): Cushing’s syndrome; ectopic ADH production (7–10%):
SIADH; hypercalcaemia (bony metastases or PTH-related peptide secretion). Skin: See also Lung cancer, non-small cell.
Eaton–Lambert myasthenic syndrome (<1%).

P R O G N O S I S: Poor. Even with limited disease, 5-year survival rate is only 15–20%. Small cell carcinoma is often disseminated by the time of presentation.

Question 61

Obstructive Sleep Apnoea - Definition

Answer 61

Characterized by recurrent collapse of the pharangeal airway and apnoea (defined as cessation of airflow for >10 s) during sleep, followed by arousal from sleep. Also known as Pickwickian syndrome.

Question 62

Obstructive Sleep Apnoea - Aetiology

Answer 62

Obstructive apnoeas occur when the upper airway narrows because of collapse of the soft tissues of the pharynx when tone in pharangeal dilators decreases during sleep. Associated with:
. excessive weight gain, smoking, alcohol or sedative use;
. enlarged tonsils or adenoids in children; and
. macroglossia, Marfan’s syndrome, craniofacial abnormalities.

Question 63

Obstructive Sleep Apnoea - History

Answer 63

Excessive daytime sleepiness (at work, driving).
Unrefreshing or restless sleep.
Morning headaches or dry mouth, difficulty concentrating, irritability or mood changes. Partner reporting snoring, nocturnal apnoeic episodes or nocturnal choking.

Question 64

Obstructive Sleep Apnoea - Examination

Answer 64

Large tongue, enlarged tonsils, long or thick uvula, retrognathia (pulled back jaws).
Neck circumference (>42 cm males, >40 cm females) is strongly correlated with presence of disease.
Obesity and hypertension is common.

Question 65

Obstructive Sleep Apnoea - Investigations

Answer 65

Video recording of episodes.
Sleep study: Managed by sleep study centre for polysomnography or diagnostic sleep
studies with monitoring of airflow, respiratory effort, pulse oximetry and heart rate. Blood: Thyroid function tests, ABG.

Question 66

Obstructive Sleep Apnoea - Management

Answer 66

Mild: Advice on sleep positions (sleep on side rather than on back), weight loss, smoking cessation, avoidance of alcohol, sedatives and late night meals.
Moderate: Mandibular advancement splints.
Severe: Nasal or face-mask CPAP uses positive pressure to maintain patency of upper airways
and prevents their closure.
Surgery: Used in severe cases with variable success (e.g. removal of nasal polyps, correction
of deviated nasal septum uvulopalatopharyngoplasty). Public health: Patient is advised to inform DVLA.
C O M P L I C A T I O N S Risk of accidents when driving or working. Worsening of congestive heart failure. Linked to “ risk of coronary artery disease and stroke.
P R O G N O S I S Short-term prognosis good with symptom improvement with CPAP. Com- pliance with advice or CPAP may be poor in long term.

Question 67

Pneumoconiosis - Definition

Answer 67

Fibrosing interstitial lung disease caused by chronic inhalation of mineral dusts.
Simple: Coalworker’s pneumoconiosis or silicosis (symptom-free).
Complicated: Pneumoconiosis (progressive massive fibrosis) results in loss of lung function. Asbestosis: A pneumoconiosis in which diffuse parenchymal lung fibrosis occurs as a result
of prolonged exposure to asbestos.

Question 68

Pneumoconiosis - Aetiology

Answer 68

Caused by inhalation of particles of coal dust, silica or asbestos (two main types of fibre: white asbestos and blue asbestos or crocidolite, the latter is more toxic).

Occupationalexposure:incoalmining,quarrying,iron and steel foundries, stone cutting, sandblasting, insulation industry, plumbers, ship builders. Risk depends on extent of exposure, size and shape of particles and individual susceptibility, as well as co-factors such as smoking and TB.

Question 69

Pneumoconiosis - History

Answer 69

Occupational history is important, there may be a long latency between disease exposure and expression.
Asymptomatic: Picked up on routine CXR (simple coal or silica pneumoconiosis). Symptomatic: There is usually insidious onset of shortness of breath and a dry cough. Occasionally, black sputum (melanoptysis) is produced in coalworker’s pneumoconiosis. Workers exposed to asbestos may develop pleuritic chest pain many years after first
exposure as a result of acute asbestos pleurisy.

Question 70

Pneumoconiosis - Examination

Answer 70

Examination may be normal.
Decreased breath sounds in coalworker’s pneumoconiosis or silicosis. End-inspiratory crepitations and clubbing in asbestosis.
Signs of a pleural effusion or right heart failure (cor pulmonale).

Question 71

Pneumoconiosis - Pathology

Answer 71

Complicated disease: There are large nodules in the lung, consisting of dust particles (coal or silica) surrounded by layers of collagen and dying macrophages. Mechanisms of damage include:
1. direct cytotoxicity by particles;
2. particle ingestion by macrophages results in activation and excessive free radical produc-
tion causing lipid peroxidation and cell injury; and
3. proinflammatory cytokines and growth factors from macrophages and epithelial cells
stimulate fibroblast proliferation and eventual scarring.
Asbestosis: Asbestos bodies consisting of fibres coated with an iron-containing protein are seen in fibrotic areas, especially in the lung bases.

Question 72

Pneumoconiosis - Investigations

Answer 72

CXR:
Simple: Micronodular mottling is present.
Complicated: Nodular opacities in the upper lobes, micronodular shadowing, eggshell
calcification of hilar lymph nodes is characteristic of silicosis. In asbestosis, there is often bilateral lower zone reticulonodular shadowing and pleural plaques, visible as white lines when calcified, often most obvious on the diaphragmatic pleura or as ‘holly leaf’ patterns.
CT scan: Fibrotic changes can be visualized early.
Bronchoscopy: Visualizes changes. Allows for bronchoalveolar lavage. Lung function tests: Restrictive ventilatory defect, impaired gas diffusion.

Question 73

Pneumoconiosis - Management

Answer 73

General: Prevention of exposure. Avoidance of further exposure.
Medical: No specific treatment other than supportive care, e.g. oxygen or trial of inhaled
steroids, and the treatment of complications.
Advice: Patients are entitled to compensation for occupational lung diseases.
COMPLICATIONS Progressive massive fibrosis, emphysema, cor pulmonale, Caplan’s syndrome, end-stage respiratory failure, benign and malignant pleural effusions, lung carcinoma and mesothelioma (malignancy of pleura, seen especially with blue asbestos, crocidolite, exposure).
P R O G N O S I S Not curable. Lifespan shortened with complicated disease. Prognosis is poor if malignancy develops.

Question 74

Pneumonia - Definition

Answer 74

Infection of distal lung parenchyma. Several ways of categorization:
. community-acquired, hospital-acquired or nosocomial;
. aspiration pneumonia, pneumonia in the immunocompromised;
. typical and atypical (Mycoplasma, Chlamydia, Legionella).

Question 75

Pneumonia - Aetiology

Answer 75

Community-acquired: Streptococcus pneumoniae (70%), Haemophilus influenzae and Moraxella catarrhalis (COPD), Chlamydia pneumonia and Chlamydia psittaci (contact with birds/parrots), Mycoplasma pneumonia (periodic epidemics), Legionella (anywhere with air conditioning), Staphylococcus aureus (recent influenza infection, IV drug users), Coxiella burnetii (Q fever, rare), TB (may present as pneumonia; see Tuberculosis).
Hospital-acquired: Gram-negative enterobacteria (Pseudomonas, Klebsiella), anaerobes (aspiration pneumonia).
Risk factors: Age, smoking, alcohol, pre-existing lung disease, immunodeficiency, contact with pneumonia.

Question 76

Pneumonia - History

Answer 76

Fever, rigors, sweating, malaise, cough, sputum (yellow, green or rusty in S. pneumoniae), breathlessness and pleuritic chest pain, confusion (severe cases, elderly, Legionella).
Atypical pneumonia: Headache, myalgia, diarrhoea/abdominal pain.

Question 77

Pneumonia - Examination

Answer 77

Pyrexia, respiratory distress, tachypnoea, tachycardia, hypotension, cyanosis.
low Chest expansion, dullness to percussion, increased tactile vocal fremitus, bronchial breathing (inspiration phase lasts as long as expiration phase), coarse crepitations on affected side.
Chronic suppurative lung disease (empyema, abscess): Clubbing.

Question 78

Pneumonia - Investigations

Answer 78

Blood: FBC (abnormal WCC), U&E (low Na + , especially with Legionella), LFT, blood cultures (sensitivity 10–20%), ABG (assess pulmonary function), blood film (RBC agglutination by Mycoplasma caused by cold agglutinins; see Anaemia, haemolytic).
CXR: Lobar or patchy shadowing, may lag behind clinical signs, pleural effusion, Klebsiella often affects upper lobes, repeat 6–8 weeks (if abnormal suspect underlying pathology, e.g. lung cancer). May detect complications: Abscess (cavitation and air-fluid level).
Sputum/pleural fluid: Microscopy, culture and sensitivity, acid-fast bacilli.
Urine: Pneumococcus and Legionella antigens.
Atypical viral serology: High Antibody titres between acute and convalescent samples
(>2 weeks post-onset).
Bronchoscopy (and bronchoalveolar lavage): If Pneumocystis carinii pneumonia is
suspected, or when pneumonia fails to resolve or when there is clinical progression.

Question 79

Pneumonia - Management

Answer 79

Refer to British Thoracic Society Guidelines 2001 and the 2004 update). Assess severity (see Prognosis; if 1 feature present, manage in hospital).
Start empirical antibiotics:
. Oral amoxicillin (0 markers);
. oral or IV amoxicillin and erythromycin (1 marker);
. IV cefuroxime/cefotaxime/co-amoxiclav and erythromycin (>1 marker);
. add metronidazole, if aspiration, lung abscess or empyema suspected;
. switch to appropriate antibiotic as per sensitivity.
Levofloxacin and moxifloxacin can provide useful alternatives in selected hospitalized patients with community-acquired pneumonia.

Supportive treatment:
. Oxygen (maintain PO2 > 8 kPa, start with 28% O2 in COPD to avoid hypercapnia);
. parenteral fluids for dehydration or shock, analgesia, chest physiotherapy;
. CPAP, BiPAP or ITU care for respiratory failure;
. surgical drainage may be needed for empyema/abscesses.
Discharge planning:
Presence of two or more features of clinical instability (“ temperature, heart rate, respiratory rate and # BP, oxygen saturation, mental status and oral intake) predict a significant chance of re-admission or mortality. Thus this assessment should be considered when planning for discharge.
Non-resolving pneumonia: Consider other causes (see Table 1).
Unusual pathogens, e.g. Chlamydia psittaci, C. burnetii, Mycobacterium tuberculosis, Nocardia, Actino- myces israelii, fungi (Aspergillus, histoplasmosis, coccidioidomycosis, blastomycosis)
Pulmonary embolism
Malignancy: Bronchogenic carcinoma, bronchoalveolar cell carcinoma, lymphoma Inflammatory: Vasculitis, Wegener’s granulomatosis, sarcoidosis, systemic lupus erythematosus Congestive heart failure
Drug toxicity
Diffuse alveolar haemorrhage
Bronchiolitis obliterans-organizing pneumonia
Eosinophilic pneumonia
Acute interstitial pneumonia
Pulmonary alveolar proteinosis

Prevention: Pneumococcal, H. influenzae type B vaccination in vulnerable groups (e.g.
elderly, splenectomized).

Question 80

Pneumonia - Prognosis

Answer 80

Most resolve with treatment (1–3 weeks). High mortality of severe pneu- monia (community-acquired 5–10%; hospital-acquired 30%, 50% in those in ITU). Markers of severe pneumonia (CURB-65 score):
. Confusion
. Urea > 7 mmol/L
. Respiratory rate 30/min
. BP: Systolic <90 mm Hg or diastolic 60 mm Hg
. Age 65 years
Other markers are hypoxia < 8 kPa, WCC < 4 or > 20 10^9/mm^3, age > 50 years.

Question 81

Pneumothorax - Definition

Answer 81

Air in the pleural space (the potential space between visceral and parietal pleura). Other variants depend on the substance in the pleural space (e.g. blood: haemothorax; lymph: chylothorax).
Tension pneumothorax: Emergency when a functional valve lets air enter the pleural space during inspiration, but not leave during expiration.

Question 82

Pneumothorax - Aetiology

Answer 82

Spontaneous: In individuals with previously normal lungs, typically tall thin males. Probably caused by rupture of a subpleural bleb.
Secondary: Pre-existing lung disease (COPD, asthma, TB, pneumonia, lung carcinoma, cystic fibrosis, diffuse lung disease).
Traumatic: Penetrating injury to chest, often iatrogenic causes, e.g. during subclavian or jugular venous cannulation, thoracocentesis, pleural or lung biopsy, or positive pressure- assisted ventilation.
Risk factors: Collagen disorders (e.g. Marfan’s disease and Ehlers–Danlos syndrome).

Question 83

Pneumothorax - History

Answer 83

May be asymptomatic if pneumothorax is small. Sudden onset breathlessness or chest pain, especially on inspiration. Distress with rapid shallow breathing if tension pneumothorax.

Question 84

Pneumothorax - Exam

Answer 84

Signs may be absent if small.
Signs of respiratory distress with reduced expansion, hyper-resonance to percussion, # breath
sounds.
Tension: Severe respiratory distress, tachycardia, hypotension, cyanosis, distended neck
veins, tracheal deviation away from side of pneumothorax.

Question 85

Pneumothorax - Investigations

Answer 85

CXR: A pneumothorax is seen as a dark area of film where lung markings do not extend to. Fluid level may be seen if there is blood present. In small pneumothoraces, expiratory films may make it more prominent.
ABG: May be necessary to determine if there is any hypoxaemia, particularly in secondary disease.

Question 86

Pneumothorax - Management

Answer 86

Tension pneumothorax (emergency): Maximum O2, insert large-bore needle into second intercostal space, midclavicular line, on side of pneumothorax to relieve pressure, insert chest drain soon after.
Small pneumothorax (<2 cm lung-pleural margin): If there is no underlying lung disease, pleural fluid or clinical compromise, reassure, analgesia if required and moderate pneumothorax (>2 cm lung-pleural margin):
. Aspiration using large-bore cannula or catheter with three-way tap: Inserted into the second intercostal space in the midclavicular line. Up to 2.5 L of air can be aspirated (stop if patient repeatedly coughs or resistance is felt). Follow-up CXR should be performed just after, 2 h and 2 weeks later. Advised to avoid diving.
. Chest drain with water seal: If aspiration fails or if there is fluid in the pleural cavity or after decompression of a tension pneumothorax. It is inserted into the fourth to sixth intercostal space in midaxillary line.
Recurrent pneumothoraces: Chemical pleurodesis (visceral and parietal pleura fusion with tetracycline or talc). Surgical pleurectomy.
Advice: Avoiding air travel until follow-up CXR confirms resolution of pneumothorax. Avoid diving unless bilateral surgical pleurectomy.

Question 87

Pulmonary Embolism - Definition

Answer 87

Occlusion of pulmonary vessels, most commonly by a thrombus that has travelled to the vascular system from another site.

Question 88

Pulmonary Embolism - Aetiology

Answer 88

Thrombus (>95% originating from DVT of the lower limbs and rarely from right atrium in patients with AF). Other agents that can embolize to pulmonary vessels include amniotic fluid embolus, air embolus, fat emboli, tumour emboli and mycotic emboli from right-sided endocarditis. Groups at risk include surgical patients, immobility, obesity, OCP, heart failure, malignancy.

Question 89

Pulmonary Embolism - History

Answer 89

H I S T O R Y Depends on the size and site of the pulmonary embolus:
Small: May be asymptomatic.
Moderate: Sudden onset dyspnoea, cough, haemoptysis and pleuritic chest pain.
Large (or proximal): All of the above plus severe central pleuritic chest pain, shock, collapse,
acute right heart failure or sudden death.
Multiple small recurrent: Symptoms of pulmonary hypertension.

Question 90

Pulmonary Embolism - Examination

Answer 90

Clinical probability assessment: Various scales can predict probability to guide further investigation and management. Use local guidelines (Table 2).
Severity of pulmonary embolism (PE) can be assessed based on associated signs:
Small: Often no clinical signs. Earliest sign is tachycardia or tachypnoea.
Moderate: Tachypnoea, tachycardia, pleural rub, low saturation O2 (despite oxygen
supplementation).
Massive PE: Shock, cyanosis, signs of right heart strain (“ JVP, left parasternal heave,
accentuated S2 heart sound).
Multiple recurrent PE: Signs of pulmonary hypertension and right heart failure.

Question 91

Pulmonary Embolism - Investigations

Answer 91

Low probability: Use D-dimer blood test (cross-linked fibrin degradation products, highly sensitive but poor specificity).
[WELLS SCORE, REVISED GENEVA SCORE]

High probability: Requires imaging.
Additional initial investigations:
Bloods: ABG, consider thrombophilia screen.
ECG: May be normal or more commonly show a tachycardia, right axis deviation or RBBB.
Classical SI, QIII, TIII pattern is relatively uncommon.
CXR: Often normal but to exclude other differential diagnoses.
Spiral CT pulmonary angiogram: First-line investigation of choice. Poor sensitivity for small emboli, but very sensitive for medium to large emboli.
Ventilation-perfusion (VQ) scan: Administration of IV 99mTc macro-aggregated albumin and inhalation of 81 krypton gas. This identifies any areas of ventilation and perfusion mismatch that would indicate infarcted lung. Not suitable if there is an abnormal CXR or coexisting lung disease due to difficulty in interpretation.
Pulmonary angiography: Gold standard, but invasive. Rarely necessary. Doppler USS of the lower limb: To examine for venous thrombosis. Echocardiogram: May show right heart strain.

Question 92

Pulmonary Embolism - Management

Answer 92

Primary prevention: Graduated pressure stockings (TEDs) and heparin prophylaxis in those at risk (e.g. undergoing surgery). Early mobilization and adequate hydration post-surgery. If haemodynamically stable: O2, anticoagulation with heparin or LMW heparin, changing
to oral warfarin therapy (INR 2–3) for a minimum of 3 months. Analgesics for pain.
If haemodynamically unstable (massive PE): Resuscitate, give oxygen, IV fluid resusci- tation, thrombolysis with tPA can be considered on clinical grounds alone if cardiac arrest
is imminent (50 mg bolus of tPA).
Surgical or radiological: Embolectomy (when thrombolysis is contraindicated). IVC filters
(Greenfield filter) may be inserted for recurrent pulmonary emboli despite adequate anticoagulation or when anticoagulation is contraindicated.