Other

Question 1

What is Pulmonary surfactant?

Answer 1

Pulmonary surfactant is a complex mixture of proteins and phospholipids. 10% is composed of SP-A (surfactant protein) SP-B and SP-C. surfactant is produced by the alveolar type 2 cells (AT-II cells).
The main function of surfactant is to reduce the surface tension of the alveoli at the onset of breathing allowing lung expansion, and subsequently preventing collapse.
Abnormalities in surfactant have been found in many child and adult lung diseases incl Respiratory Distress syndrome, bronchiolitis, COPD and ILD.

Question 2

What is the pathophysiology of Pulmonary Alveolar Proteinosis?

Answer 2

Disruption of GM-CSF signalling in macrophages leads to impairments in catabolism of surfactant proteins. Accumulation of surfactant leads to impaired gas exchange.

Question 3

What is the arterial supply to the pleura?

Answer 3

Cervical pleura - branches of subclavian artery
Costovertebral pleura - intercostal arteries
Diaphragmatic pleura - vascular plexus from surface of diaphragm
Parietal pleura - bronchial arteries

Question 4

List the bronchopulmonary segments of the right (10) and left (9) lung

Answer 4

RUL (3): apical, posterior, anterior
RML (2): lateral, medial
RLL (5): superior, medial basal, anterior basal, lateral basal, posterior basal
LUL (5): apical, posterior, anterior, superior lingula, inferior lingula
LLL (4): apical, anteriomedial basal, lateral basal, posterior basal

Question 5

Describe the anatomical borders of the mediastinum

Answer 5

Superior: thoracic inlet
Inferior: diaphragm
Anterior: sternum
Posterior: vertebral column

Question 6

List the structures which pass through the 3 openings of the diaphragm, and at which vertebral levels they do so

Answer 6

IVC - T8
Oesophagus - T10
Aorta - T12

Question 7

What is the nerve supply to the diaphragm?

Answer 7

Phrenic nerve - C3,4,5 keeps the diaphragm alive

Question 8

At how many weeks of embryological development does a) the respiratory system b) alveolar development occur?

Answer 8

A) The development of the Respiratory system occurs at around 26 days (4 weeks) gestation with a diverticulum arising from the foregut. The laryngotracheal tube and main bronchi are formed first
B) Alveolar development occurs from 28 weeks gestation, and continues beyond birth, into early childhood

Question 9

What is the cell type described?
The most common cells in sputum. Irregularly polygonal or rectangular. Well demarcated borders, small nuclei, abundant pale cytoplasm (cyanophilic to eosinophilia in Pap preparations)

Answer 9

Squamous cell

Question 10

What is the cell type described?
Columnar or triangular. Can be single, in ribbons or in flat sheets. Bluish-grey cytoplasm on MGG stains, or cyanophilic on Pap preparations. Nuclei vary in size and shape but usually basal. Cilia appear red on Pap preparations.

Answer 10

Bronchial epithelial cell

Question 11

What is the cell type described?
Columnar cells with basal nucleus. Supranuclear cytoplasm distended by globules of mucin. Cilia are absent.

Answer 11

Goblet cells

Question 12

What are Curshmann’s spirals?

Answer 12

Curshmann’s spirals are coils of compressed mucus (mucus plugs), which represent casts of small bronchioles. They are seen in sputum. They are most commonly associated with asthma.

Question 13

What are Charcot-Leyden crystals?

Answer 13

Charcot-Leyden crystals are derived from the breakdown products of eosinophil granules. They are needle shaped or diamond shaped crystals in sputum. They are associated with eosinophilia lung diseases, most commonly asthma.

Question 14

Name the receptor which is upregulated in cough hypersensitivity syndrome

Answer 14

TRPV1 is the capsaicin sensitive receptor, which is in the family of nociceptors called Transient Receptor Potential (TRP). TRPV1 is upregulated in people with cough hypersensitivity syndrome due to increased expression in neurones or airway tissues secondary to pro-inflammatory mediators.

Question 15

Why is purulent sputum green in colour?

Answer 15

Purulent sputum is green in colour due to myeloperoxidase. This is a peroxidase enzyme encoded by the MPO gene on Ch17. It is highly expressed in neutrophil granulocytes. When degranulation occurs, myeloperoxidase is released into the extra cellular space. It has a Haem pigment and therefore neutrophil rich sputum appears green.

Question 16

You are asked to review an X-coded CT scan of the chest which includes the comment ‘In the right lower lobe there is a nodular opacity which demonstrates Cheerios sign.’

Which ONE of the following is the most likely diagnosis?
A. Angioinvasive aspergillosis
B. Lung adenocarcinoma
C. Pneumocystis jirovecii infection
D. Pulmonary Pleuroparenchymal Fibroelastosis
E. ​Sarcoidosis

Answer 16

B. Lung adenocarcinoma

The Cheerio sign is a CT finding of a nodule with a hypodense centre, resembling the ring-shaped Cheerios breakfast cereal. It is caused by peribronchiolar cellular proliferation around a patent airway.

Common causes for Cheerio sign include pulmonary Langerhans cell histiocytosis and lung adenocarcinoma. Occassionally cavitating lesions of the lung, such as fungal infections, metastatic cancers , lymphoma, rheumatoid nodules and granulomatosis with polyangiitis can demonstrate this sign.

Question 17

You are asked to review an X-coded CT scan of the chest which includes the comment ‘In the right lower lobe there is a nodular opacity which demonstrates Cheerios sign.’

Which ONE of the following is the most likely diagnosis?
A. Angioinvasive aspergillosis
B. Lung adenocarcinoma
C. Pneumocystis jirovecii infection
D. Pulmonary Pleuroparenchymal Fibroelastosis
E. ​Sarcoidosis

Answer 17

B. Lung adenocarcinoma

The Cheerio sign is a CT finding of a nodule with a hypodense centre, resembling the ring-shaped Cheerios breakfast cereal. It is caused by peribronchiolar cellular proliferation around a patent airway.

Common causes for Cheerio sign include pulmonary Langerhans cell histiocytosis and lung adenocarcinoma. Occassionally cavitating lesions of the lung, such as fungal infections, metastatic cancers , lymphoma, rheumatoid nodules and granulomatosis with polyangiitis can demonstrate this sign.

Question 18

You are asked for advice on a CT scan which reports ‘there is a curvilinear opacity extending from the subpleural opacity toward the ipsilateral hilum, consistent with comet tail sign’.
Which ONE of the following is the most likely diagnosis?
A. Adenocarcinoma
B. Benign pleural fibroma
C. Malignant Mesothelioma
D. Rounded atelectasis
E. Semi-invasive aspergillosis

Answer 18

D. Rounded atelectasis
The description in the report of a curvilinear opacity that extends from a subpleural “mass” toward the ipsilateral hilum describes comet tail sign. This is produced by the distortion of vessels and bronchi that lead to an adjacent area of rounded atelectasis. The bronchovascular bundles appear to be pulled into the ‘mass’ and resemble a comet tail.

Question 19

A new diagnostic test, the electronic molecular profiling nose (or e-nose) has been developed to identify patients with COPD who also have early stage lung cancer. In a study of 1000 patients with COPD 50 patients had positive e-nose tests, and 35 of those had lung cancer proven on further testing. There were also 20 patients who had lung cancer diagnosed but who had negative e-nose tests.
Which ONE of the following is most accurate in relation to the e-nose?
A. The false positive rate was 5%
B. The true negative rate was 80%
C. The prevalence of lung cancer in this study population was 15%
D. The sensitivity was 75%
E. The specificity was 98%

Answer 19

E. The specificity was 98%

The best way to approach this sort of question is to construct a 2x2 table. You can then answer questions on true and false positive/negative rates, sensitivity, specificity, positive predictive value and negative predictive value.
Specificity = True negative / (True negative + false positive)