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Cystic fibrosis — MRCPCH FOP MCQ

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HardRespiratoryCystic fibrosisMRCPCH FOP

A 6-month-old girl has recurrent wet cough, loose greasy stools and faltering growth. She had meconium ileus at birth and now has bilateral crackles but no fever. What is the most appropriate investigation?

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Correct answer: C — Sweat chloride testing at a specialist centre

The combination of recurrent respiratory symptoms, steatorrhoea, faltering growth and meconium ileus strongly suggests cystic fibrosis, and sweat chloride testing is the key diagnostic investigation. A chest radiograph may show complications but does not confirm the diagnosis. Faecal calprotectin would be more relevant to inflammatory bowel disease. The pearl is that pancreatic features can be the clue when respiratory symptoms are non-specific.

Reference: NICE CKS Cystic fibrosis; UK Cystic Fibrosis Trust standards