This is a favourite question that I ask candidates when we are practicing chest vivas, but it works well for the other systems as well. It is a key part of understanding the purpose of the case (i.e. why is the examiner showing it) and formulating a sensible diagnosis or differential. Being able to pick the type of viva that you are in only comes with practice, be that running cases with a tutor, in a study group or on your own.
One of the great advantages of the Australian and New Zealand part II exam is that you know that there is an abnormality. You just have to find it. When you find it, try and categorise it (but remember you can't do this for every case).
Examples of types of chest vivas include:
- Interstitial lung disease
- Mediastinal masses
- Pulmonary masses and consolidation
- Pleural or chest wall processes
- Trauma
- "Train-wreck" cases (where the patient is really sick and there is lots going on)
Let's consider the example of interstitial lung disease. Sometimes, the hardest thing about working through an interstitial lung disease case is acknowledging you are in an interstitial lung disease case.
If you are looking at a chest x-ray and get the sense that there are reticular opacities, nodules or too many lines, you can start to feel comfortable that there is an interstitial process underlying everything. The associated findings, causes and complications you will be assessing for are quickly whittled down.
In these cases, the pathology is going to be diffuse and often bilateral. Think firstly about where it is. Upper and mid zones, or lower zones? Perihilar, diffuse or peripheral? You might not be able to definitely tell on a chest x-ray but you can give some broad assessments.
Secondly, think about what it is. Lines or nodules? Mass like opacification or diffuse change? Ring shaped opacities or subtle cystic shadows i.e. bronchiectasis or perhaps cystic lung disease?
Thirdly, is the volume lost or preserved? Think about whether the lungs are under inflated, normally inflated or hyperinflated (check the ribs if you are on the fence). Look at the hilar - are they pulled up or pulled down?
Pair these findings with the clinical history. If the patient is acutely unwell, you might put infection higher on your list. If they have a long history of cough and shortness of breath , pulmonary fibrosis or another chronic interstitial lung disease. For a subacute course differentials may include sarcoidosis or hypersensitivity pneumonitis. (These differentials are not exhaustive).
Then look around for associated findings such as lymphadenopathy or pleural effusions, and features which may point you to the cause (e.g. shoulder and AC joint arthritis in rheumatoid, a dilated oesophagus for scleroderma, asbestos plaques for asbestosis).
At this stage you might be able to formulate a sensible differential, or category of differential diagnosis such as upper zone fibrosis. You don't have to list every differential diagnosis under the sun (see The Goldilocks Zone for more on this), but enough to demonstrate that you can synthesize the findings and relate it to the patient the image represents. Like you would in real life. Remember the aim is to get the HRCT up so you can nail the case down byshowing off your beautiful and hard-learned categorisation of perilymphatic pulmonary nodules. Don't forget to suggest it.
A small piece of advice to finish. It is an important part of viva preparation to have spiels for set-pieces (click here for Radiopaedia.org's introduction if this term is new to you). What you don't want to do is try and cram a viva into a set-piece when it doesn't quite fit. You have to adapt to the case - not the other way around. The purpose of learning the set-piece is to give you a guide on how to answer, not a rigid script. Show your ability to think on your feet, and always consider the case in relation to the patient's age, gender and clinical history. You will be rewarded for it.