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RD7.3 | Imaging in Internal Medicine — PBL Case
CLINICAL SETTING
You are the intern on the Internal Medicine ward. Mrs Lakshmi, a 58-year-old woman with long-standing rheumatic heart disease and atrial fibrillation, is admitted with one week of worsening breathlessness, fatigue and abdominal distension. She has not been taking her medications regularly. This case unfolds over three triggers; discuss each trigger fully and agree your imaging reasoning before revealing the next.
Trigger 1: Breathlessness and a big heart on the film
On examination Mrs Lakshmi is breathless at rest with a raised JVP, bibasal crackles and pitting pedal oedema. A bedside chest radiograph shows an enlarged cardiac silhouette (cardiothoracic ratio ~0.6 on a PA film), upper-lobe blood diversion, Kerley B lines and small bilateral pleural effusions. Her oxygen saturation is 90% on room air.
DISCUSSION POINTS
- How do you read this chest radiograph as a 'pressure gauge'? Identify each sign and the stage of rising pulmonary venous pressure it represents.
- What single imaging investigation would you request next to guide long-term management, and what specific parameter are you seeking from it?
- How would the ejection fraction (e.g. HFrEF <40% versus a preserved EF) change your understanding of her heart failure and its treatment?
Click to reveal Trigger 2: A sudden change on the ward round (discuss previous trigger first!)
Trigger 2: A sudden change on the ward round
On day 3, while still being treated for heart failure, Mrs Lakshmi suddenly develops dense weakness of the left side of her face and arm with new difficulty speaking. She is in atrial fibrillation and her anticoagulation had been stopped before admission. The stroke team is called.
DISCUSSION POINTS
- Given her atrial fibrillation and stopped anticoagulation, what is the most likely mechanism of this event, and what is the single most urgent imaging investigation?
- Why must a non-contrast CT brain be performed before any decision about thrombolysis, and what early CT signs (hyperdense MCA, loss of grey–white differentiation, insular ribbon sign) would you actively look for?
- How would the CT result — haemorrhage versus no haemorrhage with a hyperdense MCA — change the immediate management pathway?
Click to reveal Trigger 3: The distended abdomen (discuss previous trigger first!)
Trigger 3: The distended abdomen
As her cardiac and neurological issues are stabilised, attention turns to her abdominal distension. Examination suggests ascites, and her liver function tests are abnormal. There is a history of long-standing right heart strain, and the team wonders whether there is underlying chronic liver disease. An abdominal ultrasound is requested.
DISCUSSION POINTS
- Why is ultrasound the first-line imaging modality for diffuse liver disease here, and what features would distinguish fatty liver from cirrhosis with portal hypertension?
- If a focal liver lesion were found in a cirrhotic liver, what further imaging would you request and what enhancement pattern would suggest hepatocellular carcinoma?
- How would her cardiac and renal status influence decisions about iodinated contrast, and what surveillance would you recommend if cirrhosis is confirmed?
Group Task Assignments
- Construct a single integrated imaging timeline for Mrs Lakshmi across all three problems (heart failure, stroke, liver disease), justifying the order of investigations against her acuity, haemodynamic status and renal function.
- For each modality used (CXR, echocardiography, non-contrast CT brain, abdominal ultrasound, multiphasic CT/MRI), summarise the specific clinical question it answers and the key finding that changes management.
- Prepare a short teaching summary on contrast and radiation safety in a comorbid internal-medicine patient, including when iodinated contrast should be used with caution (eGFR <30).
Learning Issues
Research these questions and bring your findings to the discussion.
- [RD7.3] How are chest radiograph and echocardiographic findings integrated to diagnose, classify and manage heart failure?
- [RD7.3] Why is non-contrast CT brain the mandatory first investigation in acute stroke, and how do its findings determine thrombolysis or thrombectomy?
- [RD7.3] What is the staged imaging strategy (ultrasound first, then CT/MRI) for liver parenchymal disease and HCC surveillance, and how do comorbidities modify contrast use?