Paeds Cases · nephrology-urology-fluids-and-electrolytes
Paediatric kidney assessment OSCE — febrile infant, bag culture and residual-risk counselling
Observed structured encounter testing urine collection method choice, dipstick and microscopy interpretation, reliable-sample confirmation, and family counselling after an equivocal culture in a febrile infant.
osce clinical reasoning and communication station
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Target exams
RACP General PaediatricsRACP DCEMRCPCH ClinicalRCPSC Pediatrics
Prompt
A 14-month-old febrile infant has a bag-urine culture growing mixed growth. The candidate must decide collection method, interpret the dipstick and microscopy, and explain the plan to the family under uncertainty.
Candidate brief
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Decide whether the bag-urine result can confirm infection, and state the preferred next step. [3]
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Interpret the dipstick and microscopy provided, and integrate them with the clinical picture. [2]
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Explain the plan to the family in plain language, including safety-netting. [3]
Scripted clinical data
- 14-month-old, day 2 of fever, irritable but perfusing well, mildly dehydrated. [3]
- Bag-urine dipstick: leukocyte esterase positive, nitrite negative, blood negative, protein trace. [2]
- Bag-urine culture: mixed growth of coliforms and skin flora. [3]
- No history of recurrent urinary tract infection or antenatal renal abnormality. [3]
Expected performance
Collection method
- Recognise that bag urine has a high contamination rate and mixed growth cannot confirm infection. [3] [5]
- Request a clean-catch or catheter sample for diagnosis, and weigh the child's clinical state in deciding how urgently. [3] [5]
Dipstick and microscopy interpretation
- Leukocyte esterase positive with nitrite negative is a weaker signal for infection; nitrite needs bladder dwell time. [2]
- Integrate dipstick with culture and clinical appearance rather than acting on the strip alone. [2] [3]
- Consider asymptomatic bacteriuria and avoid over-treating a contaminated result. [6]
Communication
- Explain in plain language: the first sample may have picked up skin bacteria, so a cleaner sample is needed to be sure before committing to treatment. [3]
- Give clear safety-net and return triggers, and describe what would prompt starting antibiotics in the interim. [3]
Handover
- State the working concern, the residual risk, the planned reliable sample, the owner, and the review timeframe. [3]
Examiner scoring anchors
| Domain | Borderline | Clear pass |
|---|---|---|
| Collection method | Accepts bag result | Requests reliable sample and justifies it |
| Interpretation | Reads dipstick alone | Integrates dipstick, culture and clinical state |
| Communication | Jargon-heavy | Plain language with usable safety-net |
| Handover | Forgets owner or timeframe | Owner, plan and review time stated |
Common fails
- Treating a mixed-growth bag culture as confirmed infection. [3]
- Reading the dipstick without the microscopy or the clinical picture. [2]
- Forgetting to give a usable safety-net or a review timeframe. [3]
- Over-treating asymptomatic or contaminated bacteriuria. [6]
References
- [1]Schwartz GJ, et al New equations to estimate GFR in children with CKD J Am Soc Nephrol, 2009.PMID 19158356
- [2]Simerville JA, et al Urinalysis: a comprehensive review Am Fam Physician, 2005.PMID 15791892
- [3]Whiting P, et al Rapid tests and urine sampling techniques for the diagnosis of urinary tract infection (UTI) in children under five years: a systematic review BMC Pediatr, 2005.PMID 15811182
- [4]Stevens PE, et al Evaluation and management of chronic kidney disease: synopsis of the kidney disease: improving global outcomes 2012 clinical practice guideline Ann Intern Med, 2013.PMID 23732715
- [5]Bogie AL, et al Is There a Difference in the Contamination Rates of Urine Samples Obtained by Bladder Catheterization and Clean-Catch Collection in Preschool Children? Pediatr Emerg Care, 2021.PMID 34772880
- [6]Shaikh N, et al Prevalence of Asymptomatic Bacteriuria in Children: A Meta-Analysis J Pediatr, 2020.PMID 31787323