Cystic fibrosis is a serious genetic disease that usually gets caught through newborn screening tests. But this case shows it can sometimes be missed. A 5-year-old boy had breathing problems, stomach issues, and wasn’t growing properly, yet his newborn screening came back normal. Doctors eventually discovered he had cystic fibrosis through additional testing. This story is important because it reminds doctors to keep cystic fibrosis in mind even when initial screening tests seem fine, especially if a child keeps getting respiratory infections and digestive problems.

The Quick Take

  • What they studied: Why a child with cystic fibrosis wasn’t diagnosed until age 5, even though newborn screening should have caught it earlier
  • Who participated: One 5-year-old African American boy with a history of repeated lung infections, digestive problems, and slow growth
  • Key finding: The boy had cystic fibrosis confirmed by sweat chloride tests and genetic testing, despite having a normal newborn screening result
  • What it means for you: If your child has repeated respiratory infections, digestive issues, or isn’t growing well, ask your doctor about cystic fibrosis testing even if newborn screening was normal. Early diagnosis and treatment can significantly improve outcomes

The Research Details

This is a case report, which means doctors documented the medical story of one patient in detail. The boy presented to doctors with multiple health problems: frequent respiratory infections with fevers, digestive issues including oily stools and a prolapsed rectum, poor weight gain, speech delays, and a distinctive rash. Doctors performed various tests including blood work, stool analysis, and a sweat chloride test (the gold standard for cystic fibrosis diagnosis). They also did genetic testing to identify the specific mutations causing his disease.

The case report format is useful for highlighting unusual presentations or diagnostic challenges. In this situation, the boy’s normal newborn screening initially made doctors less suspicious of cystic fibrosis, which delayed his diagnosis by five years. By documenting this case, the doctors wanted to alert other healthcare providers to remain vigilant for cystic fibrosis even when screening tests appear normal.

Once diagnosed, the boy started pancreatic enzyme replacement therapy, which helped his body digest food better and improved his nutritional status and respiratory symptoms.

Case reports are important for identifying gaps in our current diagnostic approaches. This case demonstrates that newborn screening, while very effective, isn’t perfect. Some children with cystic fibrosis can slip through the system, especially if they have atypical presentations. By sharing this story, doctors help other healthcare providers recognize warning signs they might otherwise miss.

This is a single case report, which is the lowest level of scientific evidence. It describes one patient’s experience and cannot prove that delayed diagnosis is common or predict outcomes for other children. However, case reports are valuable for raising awareness about diagnostic challenges and unusual presentations. The detailed documentation of symptoms, test results, and response to treatment provides useful clinical information for other doctors.

What the Results Show

The 5-year-old boy presented with a combination of respiratory and digestive symptoms that should have raised suspicion for cystic fibrosis. His respiratory issues included recurrent infections and fevers. His digestive problems included oily stools (a sign of fat malabsorption) and a prolapsed rectum. He was significantly underweight at the 5th percentile for his age and had delayed speech development.

Laboratory testing revealed several abnormalities: elevated amylase (an enzyme related to pancreatic function), low vitamin D (common in cystic fibrosis due to fat malabsorption), and high fecal calprotectin (a marker of intestinal inflammation). Most importantly, his sweat chloride test showed values of 92 and 96 mmol/L, which are diagnostic for cystic fibrosis (normal is below 30). Genetic testing confirmed he had two copies of the DeltaF508 mutation, one of the most common cystic fibrosis mutations.

Despite these clear diagnostic findings, the boy’s newborn screening had been normal, which initially delayed diagnosis. Once he started pancreatic enzyme replacement therapy, his nutritional status improved significantly, and his respiratory symptoms improved as well.

The case highlighted several secondary findings that are typical of cystic fibrosis: finger clubbing (thickened fingertips), a maculopapular rash, and speech delay (likely related to overall poor health and nutrition). The elevated pancreatic enzymes and low vitamin D indicated pancreatic insufficiency and fat-soluble vitamin malabsorption, both common complications of cystic fibrosis.

This case aligns with existing medical knowledge that cystic fibrosis can occasionally be missed by newborn screening, particularly in certain populations or with atypical presentations. Previous research has shown that newborn screening programs catch approximately 95-98% of cystic fibrosis cases, but this case represents the small percentage that are missed. The boy’s presentation with both respiratory and gastrointestinal symptoms is typical of cystic fibrosis, but the normal newborn screening created diagnostic confusion.

This is a single case report describing one patient’s experience. It cannot establish how common delayed diagnosis is, whether certain populations are at higher risk, or whether outcomes would be similar for other children. The case does not include information about why the newborn screening was normal or whether there were any technical issues with the screening process. Additionally, the long-term outcomes for this child beyond the initial treatment response are not described.

The Bottom Line

Healthcare providers should maintain suspicion for cystic fibrosis in children with recurrent respiratory infections and digestive problems, even if newborn screening was normal (moderate confidence). Parents concerned about these symptoms should discuss cystic fibrosis testing with their pediatrician (moderate confidence). Early diagnosis and treatment with pancreatic enzymes and respiratory therapies can significantly improve quality of life and outcomes (high confidence based on established cystic fibrosis management).

Parents and caregivers of children with unexplained recurrent respiratory infections, digestive problems, poor growth, or failure to thrive should be aware of this case. Healthcare providers, especially primary care doctors and pediatricians, should remember that cystic fibrosis can occasionally be missed by newborn screening. This case is particularly relevant for families with a history of cystic fibrosis or genetic carriers.

In this case, improvement in nutritional status and respiratory symptoms began after starting pancreatic enzyme therapy, though the timeline for complete symptom resolution is not specified. Generally, children with cystic fibrosis show nutritional improvement within weeks of starting appropriate enzyme therapy, but long-term respiratory outcomes depend on consistent treatment and management.

Want to Apply This Research?

  • Track your child’s weight, growth percentile, and frequency of respiratory infections monthly. Note any changes in stool consistency or digestive symptoms. This data can help identify patterns that might warrant discussion with your doctor about cystic fibrosis screening.
  • If your child has symptoms suggestive of cystic fibrosis, use the app to schedule a doctor’s appointment and prepare a list of symptoms to discuss. Document when symptoms started and how they’ve progressed to share with your healthcare provider.
  • For children diagnosed with cystic fibrosis, use the app to track medication adherence (pancreatic enzymes, vitamins), monitor weight gain and growth, record respiratory symptoms and infections, and track nutritional intake to ensure adequate calorie consumption for growth and development.

This case report describes one child’s experience with delayed cystic fibrosis diagnosis. It is not medical advice and should not be used for self-diagnosis. If you are concerned that your child may have cystic fibrosis or similar symptoms, consult with a qualified healthcare provider for proper evaluation and testing. While this case highlights the importance of considering cystic fibrosis in children with certain symptoms, only medical professionals can diagnose this condition through appropriate testing. Always seek professional medical guidance for your child’s health concerns.