Definitions

Question 1

Coryza (Common Cold)

Answer 1

Acute viral infection of the nasal passages; highly infectious due to rhinoviruses, coronaviruses and adenoviruses. Spread via droplets, facilitated by overcrowding and poor ventilation.

Question 2

Sinusitis

Answer 2

Bacterial/fungal infection of paranasal sinuses, usually preceded by coryza. Can occur with asthma.

Question 3

Rhinitis

Answer 3

Sneezing attacks, nasal blockage/discharge occurring >1hr on most days. Seasonal/Intermittent = limited period of the year; “hay-fever” but not restricted to grass pollen.

Question 4

Pharyngitis

Answer 4

Endemic adenovirus infection, causing reddened oropharynx and soft palate and inflamed tonsils.

Question 5

Acute Laryngotracheobronchitis

Answer 5

Occasional complication of URTIs, particularly those caused by parainfluenza viruses and measles. Most severe in children < 3yrs. Inflammatory oedema usually present which can spread to vocal cords.

Question 6

Acute Epiglottitis

Answer 6

Life-threatening airway obstruction in children aged 2-7yrs caused by H. influenzae.

Question 7

Influenza

Answer 7

Influenza A (pandemics) and Influenza B (localised outbreaks) incubate within 3 days. Not a cold!

Question 8

Acute Bronchitis

Answer 8

“Cold which goes to the chest” – acute infection of bronchi causing them to become inflamed. Usually arises from Strep. pneumoniae/H. influenzae infections, or in people with COPD.

Question 9

Pneumonia

Answer 9

Acute infection of the lungs causing inflammation. Community, Hospital and Immunocompromised acquired pneumonia. Main causes: Strep. pneumoniae, H. influenzae, Staph. aureus, Influenza A. Atypical causes: Mycoplasma, Legionella, Chlamydophila pneumoniae/psittaci, coxiella burnetti.

Question 10

COPD (Chronic Obstructive Pulmonary Disease)

Answer 10

Encompasses 2 main clinical syndromes: chronic bronchitis and emphysema. Characterised by airflow obstruction that is mostly irreversible

Question 11

Asthma

Answer 11

Chronic inflammatory condition where reversible obstruction of the airways occurs. Airflow limitation -> airway hyper-responsiveness -> bronchial inflammation.

Question 12

Obstructive Sleep Apnoea

Answer 12

Airway becomes closed during sleep; muscles hypotonic during sleep and thus do not open airway. Partial occlusion results in snoring; complete occlusion results in apnoea (cessation of breathing).

Question 13

Bronchiectasis

Answer 13

Abnormal permanent dilatation of airways, resulting inflammation and thickening of walls. Mucociliary transport mechanism is impaired and thus recurrent bacterial infections ensue. Cystic fibrosis = most common cause.

Question 14

Lung Abscess

Answer 14

Localised suppuration assoc. with cavity formation on CXR/CT

Question 15

Cystic Fibrosis

Answer 15

Autosomal recessive disorder in which there is a defect in the CFTR gene, a critical chloride channel. Failed opening of Cl channel -> ↑cAMP, resulting in ↓Cl and ↑Na -> ↑viscosity of airway secretions.

Question 16

Tuberculosis

Answer 16

Airborne infection spread by droplets by Mycobacterium species. Affects 1/3 of population. Caseating granulomatous inflammation (necrotic centre; surrounded by epitheloid cells and Langhan’s giant cells; formation of Ghon focus/complex). Primary=first infection. Latent=asymptomatic, smear –ve.

Question 17

Sarcoidosis

Answer 17

Multisystem non-caseating granulomatous Type IV hypersensitivity disorder of unknown aetiology.

Question 18

Wegener’s Granulomatosis

Answer 18

Granulomatous disease predominantly affecting small arteries. Lesions in URT, lungs, kidney.

Question 19

Churg-Strauss Syndrome

Answer 19

Eosinophilic infiltration with high blood eosinophil count, vasculitis of small arteries and veins. Predominately affects 40 year old males.

Question 20

Systemic Lupus Erythematosis

Answer 20

Chronic type III hypersensitivity disease that causes inflammation in various parts of body.

Question 21

Idiopathic Pulmonary Fibrosis

Answer 21

Patchy scarring of lung with collagen deposition and honeycombing. Late onset. Commoner in males.

Question 22

Extrinsic Allergic Alveolitis (Hypersensitivity Pneumonitis)

Answer 22

Widespread diffuse inflammatory reaction in small airways and alveoli due to inhalation of foreign antigens, usually from animals. Cigarette smokers actually have decreased risk. Type III hypersensitivity.

Question 23

Coal-Worker’s Pneumoconiosis

Answer 23

Dust particles typically 2-5 micrometres in diameter are retained in small airways and alveoli. Simple Pneumoconiosis more common form; refers to deposition of coal dust in lung. Symptoms usually COPD-related. CXR fine micro-nodular shadowing. Progressive Massive Fibrosis round fibrotic masses several cm in diameter develop in upper lobes -> apical destruction of lung. Necrotic central cavities.

Question 24

Asbestosis

Answer 24

Fibrosis causes by asbestos dust exposure.

Question 25

Pneumothorax

Answer 25

Air in the pleural space. May be spontaneous (tall, thin males) or the result of trauma to the chest.

Question 26

Empyema

Answer 26

Pus in the pleural space. Usually complication of pneumonia. Exudate of pH< 7.2 very suggestive.

Question 27

Pleural Effusions

Answer 27

Excessive fluid in the pleural space. Transudate protein < 30g/l LDH < 200 Heart failure, nephrotic syndrome, pericarditis Exudate protein > 30g/l LDH > 200 Pneumonia, cancer, TB, autoimmunity, MI, pancreatitis

Question 28

Respiratory Failure

Answer 28

Occurs when gas exchange is inadequate, resulting in hypoxia. It is defined as PaO2 <8kPa, subdivided according to PaCO2 level. Type I Respiratory Failure = hypoxia (PaO2 < 8kPa) with normal or low PaCO2 Type II Respiratory Failure = hypoxia (PaO2 < 8kPa) + hypercapnia (PaCO2 > 6.0 kPa)

Question 29

Acute Respiratory Distress Syndrome (Acute Lung Injury)

Answer 29

Respiratory distress due to stiff lungs (reduce pulmonary compliance) and gas exchange impairment. Lung injury, severe sepsis and pneumonia result in fibrous exudate lining alveolar walls, impairing gas exchange and destroying alveoli.

Question 30

Pulmonary Hypertension/Cor Pulmonale

Answer 30

Defined as mean pulmonary artery pressure of ≥25mmHg at rest. Cor pulmonale = right heart failure due to pulmonary hypertension. Can occur in advanced COPD: alveolar collapse (emphysema) results in hypoxia which causes vasoconstriction, increasing pressure in the right side of the heart.

Question 31

Pulmonary Embolism

Answer 31

Thrombus, usually from systemic veins, lodges in pulmonary arteries. Virchow’s triad: endothelial damage, abnormal blood flow or hypercoagulable blood -> clot formation.

Question 32

Pulmonary Oedema

Answer 32

Accumulation of fluid in lung interstitium/alveolar spaces. Usually due to congestive heart failure.

Question 33

Lung Cancer

Answer 33

Small Cell Carcinoma - Arise from APUD cells; secrete ACTH, often centrally located, rapid metastasis
Squamous Cell Carcinoma - Most common. Arise from epithelial cells, occasionally cavitates; central necrosis, local, slow metastasis. Hypercalcaemia, PTH
Adenocarcinoma - Common in non-smokers; smoking can cause it, arises from mucus-secreting glandular cells, metastasises widely
Large Cell Carcinoma - Poorly differentiated, metastasises early on