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RD7.5 | Imaging in Paediatrics — PBL Case

CLINICAL SETTING

It is a busy evening in a district hospital paediatric outpatient clinic. A 14-month-old boy, Arjun, is brought by his anxious grandmother. He has had a low-grade fever and an irritable, intermittent cough for the past day. He is feeding reasonably, is alert, and his oxygen saturation is 96% on room air. The grandmother is convinced 'something is stuck in his chest' and is demanding a CT scan 'to be sure'. Your task as the clinical team is to decide what imaging, if any, is justified — balancing the family's anxiety against the principle of imaging children gently.

Trigger 1: The well child and the demand for a scan

On full examination Arjun is well: he is playful, well-perfused, has a respiratory rate of 34/min, no recession, and scattered transmitted upper-airway sounds but clear lung fields on auscultation. There is no definite history of a choking episode — the grandmother says he 'might have' put a small toy part in his mouth earlier in the day but she did not see him swallow or choke on anything. The grandmother repeats her request for an urgent CT scan.

DISCUSSION POINTS

  • Is any imaging indicated at this point? Justify your answer using the principle that imaging should be ordered only when the result will change management.
  • Why is a CT scan an inappropriate first response here? What are the specific concerns about CT in a 14-month-old?
  • How would you explain to the grandmother, in plain language, why withholding a scan is the safer, more responsible choice for her grandson right now?
  • What safety-net advice and follow-up plan would you give so that the family knows exactly when to return?
Click to reveal Trigger 2: A clearer story emerges (discuss previous trigger first!)

Trigger 2: A clearer story emerges

Two days later Arjun returns. The cough has become persistent and is now associated with an audible wheeze on the right side. The grandmother now clearly recalls that the day before the first visit he had a sudden coughing and choking fit while playing near his older sibling's building blocks, after which he settled. On examination there is reduced air entry on the right with a monophonic wheeze. A frontal inspiratory chest radiograph is reported as 'normal'.

DISCUSSION POINTS

  • How does the new history change your level of clinical suspicion, and why is the history more important than the radiograph here?
  • The inspiratory film is 'normal'. Explain why this does NOT exclude an aspirated foreign body in a child of this age.
  • What additional radiographic views or techniques could help unmask an indirect sign, and what specific indirect signs would you look for (and how would the mediastinum shift in air-trapping versus collapse)?
  • What is the definitive next step given a convincing choking history, and why is it both diagnostic and therapeutic?
Click to reveal Trigger 3: After bronchoscopy — a second clue (discuss previous trigger first!)

Trigger 3: After bronchoscopy — a second clue

Rigid bronchoscopy confirms and removes a small fragment of plastic from the right main bronchus, and Arjun recovers well. During the admission, however, the nursing notes reveal that Arjun has also had two documented febrile urinary tract infections in the past six months. The paediatric team asks whether any uroradiological investigation is warranted before discharge planning.

DISCUSSION POINTS

  • Using age- and risk-based (NICE/ISPN) protocols, decide what uroradiological work-up, if any, is appropriate for a 14-month-old with recurrent febrile UTIs.
  • Map each potential test to the single question it answers: ultrasound (anatomy), MCUG/VCUG (reflux and its grading I-V), DMSA (cortical scarring). Which would you order first and why?
  • How would an abnormal result on each test change Arjun's longer-term management (for example, antibiotic prophylaxis, surgical referral, or scar surveillance)?
  • Reflect on the whole case: how did the 'image gently' principle and the 'one tool, one question' rule guide every imaging decision across his respiratory and urinary problems?

Group Task Assignments

  • Group A: Build a one-page 'imaging decision flowchart' for a child presenting with possible foreign body aspiration, from history through plain films and unmasking views to bronchoscopy, annotating where each indirect sign appears.
  • Group B: Draft a parent-facing explanation (in lay language) of why a CT scan is not the automatic first test in children, and what 'image gently' means for their child.
  • Group C: Construct a comparison table of USG vs MCUG vs DMSA in paediatric UTI — the question each answers, what it shows, the radiation involved, and the management decision it informs.

Learning Issues

Research these questions and bring your findings to the discussion.

  1. [RD7.5] Why are children more radiosensitive than adults, and how does the ALARA / 'image gently' principle translate into modality choice (USG/MRI over CT) in paediatric imaging?
  2. [RD7.5] What is the imaging strategy for paediatric chest infection — when is a CXR indicated, what is the role of ultrasound for effusion/empyema, and when (if ever) is CT justified?
  3. [RD7.5] Why does a normal chest radiograph not exclude foreign body aspiration, what direct and indirect signs may be present, and why is bronchoscopy both diagnostic and therapeutic?
  4. [RD7.5] How do age- and risk-based protocols (NICE/ISPN) determine which children with UTI are imaged, and how do USG, MCUG (reflux grades I-V) and DMSA (cortical scarring) each contribute?