History 35-year-old man with sudden-onset left-sided pleuritic chest pain and rapidly worsening breathlessness. HR 128, BP 92/60, RR 32, SpO₂ 86% on room air.
Frontal chest radiograph · Click an image to enlarge.
Answer each question aloud before you reveal it. Marks and domains appear only in the revealed answers, as in the exam.
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Q1 What are the pertinent findings?
Reveal answer
A Annotated 3 marks Observation
- Large left pneumothorax: visible visceral pleural edge, with no lung markings beyond it (1)
- Mediastinum and trachea displaced to the right (away from the abnormal side) (1)
- Depressed / flattened left hemidiaphragm and widened left intercostal spaces (0.5)
- Small left pleural effusion (blunted left costophrenic angle) (0.5)
Examiner note 'Left pneumothorax' alone scores 1/3. The shift and the diaphragm are the tension signs.
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Q2 What is your preferred diagnosis? Give one differential diagnosis for the lucent hemithorax.
Reveal answer
2 marks Interpretation
- Preferred: left tension pneumothorax (radiographic signs of tension in this clinical setting) (1)
- Differential: giant bulla / bullous emphysema (accept skin fold artefact for 0.5) (1)
Examiner note Tension is a clinical, physiological diagnosis. The film supports it; the BP and SpO₂ confirm it.
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Q3 The systolic BP falls to 80 mmHg while you review the film. What is the immediate management, and what is the role of further imaging?
Reveal answer
2 marks Management/Safety
- Immediate decompression; no further imaging (no CT) before treatment (1)
- Needle or finger thoracostomy at the 4th/5th intercostal space just anterior to the mid-axillary line in adults (ATLS 10th ed.), then a definitive ICC; post-procedure CXR for tube position and re-expansion (1)
Examiner note ATLS 10th ed. moved adult needle decompression to the 4th/5th ICS, anterior to the mid-axillary line; 2nd ICS mid-clavicular line is still an option. Follow the local EMST/ED protocol.
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Q4 Why does this condition cause haemodynamic compromise?
Reveal answer
1 mark Applied sciences
- A one-way valve leak raises intrapleural pressure; mediastinal shift and compression of the great veins reduce venous return and preload, so cardiac output falls (obstructive shock) (1)
Examiner note Hypoxia from shunt through the collapsed lung adds to it.
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Q5 You are the radiology registrar and you find this film on the ED worklist. What do you do?
Reveal answer
2 marks Intrinsic roles
- Phone the treating ED doctor directly and immediately (critical finding); do not rely on the written report (1)
- Closed loop: identify yourself and the patient (2 identifiers), state the finding and urgency, ask for read-back; record the name, time and content of the call in the report (1)
Examiner note LO 6.1.26, 6.1.28 and 6.1.29: recognise emergencies, communicate directly, confirm receipt.
End of the OSCER block (10 marks).
Beyond the exam: teaching extension
Q6–Q10: not part of the 10-mark OSCER block. Untimed, viva-style discussion: mimics and pitfalls, complications, guidelines and report wording.
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Q6 How does a pneumothorax look on a supine film, and why is it easy to miss?
Reveal answer
- Air collects anteriorly and inferiorly: deep sulcus sign (deep, lucent costophrenic angle)
- Hyperlucent upper abdomen or hemithorax; unusually sharp heart border and hemidiaphragm
- No apical rim of air, so the classic pleural line may be absent
- In trauma, CT finds 'occult' pneumothoraces that the supine CXR misses
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Q7 What are the common mimics, and how do you separate them?
Reveal answer
- Skin fold: a broad edge rather than a thin white line, often running beyond the chest wall; lung markings continue past it
- Giant bulla: concave inner margin, septations; CT before an ICC if in doubt (a drain into a bulla risks a bronchopleural fistula)
- Medial border of the scapula, clothing, tubing; hyperlucency after mastectomy
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Q8 How do current guidelines classify pneumothorax and decide on intervention?
Reveal answer
- Primary spontaneous, secondary spontaneous (underlying lung disease), traumatic, iatrogenic; tension is a physiological state, not a size
- BTS 2010: 'large' = visible rim ≥ 2 cm at the level of the hilum
- BTS 2023: symptoms, physiology and patient priorities drive intervention more than size; options include conservative care, needle aspiration and ambulatory devices for PSP
- Tension or haemodynamic compromise: immediate decompression in every guideline
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Q9 Describe the 'safe triangle' for ICC insertion. Which complications do you check for on the post-drain film?
Reveal answer
- Borders: anterior border of latissimus dorsi, lateral border of pectoralis major, a line at the level of the nipple (5th ICS); apex below the axilla
- Insert just above the upper border of the rib to avoid the intercostal neurovascular bundle
- Check for: malposition (intrapulmonary, fissural, subcutaneous, kinked), re-expansion pulmonary oedema, surgical emphysema, residual pneumothorax, haemothorax
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Q10 Draft the key sentences of your report.
Reveal answer
- 'Large left pneumothorax with rightward mediastinal shift and depression of the left hemidiaphragm, in keeping with tension physiology in this clinical setting. Small left pleural effusion.'
- 'Discussed by telephone with Dr [name], ED, at [time]; read-back confirmed.'
End of questions. Reveal the diagnosis, key takeaways and syllabus mapping below.
Reveal diagnosis, key takeaways & syllabus mapping
Diagnosis Tension pneumothorax (left)
Key takeaways
- Tension pneumothorax is a clinical emergency: decompress first; imaging must not delay treatment.
- Name the tension signs: contralateral mediastinal shift, depressed ipsilateral hemidiaphragm, widened rib spaces.
- Exclude a bulla before an ICC in emphysematous lungs; CT if stable and in doubt.
- Phone it: direct, closed-loop communication and documentation of every critical result.
Syllabus mapping
| OSCER station | Thoracic and Cardiovascular |
|---|---|
| Learning Outcomes section | §6.5 Cardiothoracic (+ §6.1.26, 6.1.28–29) |
| Appendix 1 condition | Pneumothorax including non-traumatic (Appendix 1 E, Cardiothoracic, Traumatic conditions, p69) |
| Category | Category 1 |
| Key Condition | Yes |
| Core marks by domain | Observation 3 · Interpretation 2 · Management/Safety 2 · Applied sciences 1 · Intrinsic roles 2 (= 10) |
| Learning objectives | Recognise a large pneumothorax and the radiographic signs of tension; Put decompression before imaging; Communicate a critical result with closed-loop documentation |
Mapped to the RANZCR Clinical Radiology Learning Outcomes v1.3 (January 2024), section 6 and Appendix 1.
Further reading
- American College of Surgeons Committee on Trauma. Advanced Trauma Life Support (ATLS) Student Course Manual. 10th ed. Chicago: ACS; 2018. (Taught in Australia as EMST through RACS.)
- Roberts ME, Rahman NM, Maskell NA, et al. British Thoracic Society Guideline for pleural disease. Thorax. 2023;78(Suppl 3):s1–s42. PMID 37433578.
- MacDuff A, Arnold A, Harvey J. Management of spontaneous pneumothorax: British Thoracic Society Pleural Disease Guideline 2010. Thorax. 2010;65(Suppl 2):ii18–ii31. PMID 20696690.
- RANZCR. Clinical Radiology Learning Outcomes, v1.3 (January 2024), §6 and Appendix 1. Sydney: RANZCR.
- RANZCR. Clinical Radiology Phase 2 OSCER Sample Questions, v1.6 (4 May 2026). Sydney: RANZCR. (Format reference only; no RANZCR images reproduced.)
Always check current Australian/local guidelines.
Image credits
- A by User:Clinical Cases, CC BY-SA 2.5, via Wikimedia Commons. Changes: resized and re-encoded (WebP/JPEG). Teaching arrows and labels are a separate overlay added by this site. Adapted image shared under the same licence.
Original file titles are listed on the image credits page (they may reveal the diagnosis).