Cystic Fibrosis
This 9-month-old infant with meconium ileus at birth, chronic respiratory symptoms (wheezing, labored breathing, productive cough), and malodorous greasy stools most likely suffers from cystic fibrosis.
Diagnostic Rationale
The clinical presentation is pathognomonic for cystic fibrosis based on several key features:
Meconium ileus occurs in 10-20% of newborns with cystic fibrosis and represents the earliest clinical manifestation, with a median age of diagnosis of 0.2 months in these patients 1, 2, 3. When meconium ileus is present at birth, cystic fibrosis is the underlying diagnosis in the vast majority of cases 4, 5, 6.
The malodorous and greasy stools indicate pancreatic exocrine insufficiency with fat malabsorption (steatorrhea), which occurs in 85% of individuals with cystic fibrosis 1. This is directly caused by defective CFTR protein function affecting pancreatic secretions 1.
The chronic respiratory symptoms (wheezing, labored breathing, productive cough) at 9 months reflect early pulmonary involvement characteristic of cystic fibrosis, with viscous mucus accumulation leading to recurrent and persistent pulmonary infections 1, 2.
Immediate Diagnostic Confirmation
Sweat chloride testing is the gold standard and definitive diagnostic test that must be performed immediately 1, 2, 7, 3:
- Values >60 mEq/L confirm the diagnosis 2, 7, 3
- Values between 30-59 mEq/L are intermediate and require genetic testing for confirmation 2, 7, 3
- Infants with cystic fibrosis often have initial values in the 30-59 mEq/L range 2, 3
CFTR genetic testing should be performed simultaneously to identify specific mutations, with detection of two disease-causing CFTR mutations on biallelic alleles confirming the diagnosis 1, 2, 7.
Critical Immediate Management
Respiratory Management
Aggressive respiratory intervention must begin immediately to prevent irreversible lung damage 7:
Start empiric antibiotics targeting Haemophilus influenzae, Staphylococcus aureus, and Pseudomonas aeruginosa 2, 7. This is critical because Pseudomonas infection leads to irreversible lung damage, with survival to 16 years of only 53% in chronically infected children versus 84% without chronic infection 7.
Initiate chest physiotherapy immediately to establish airway clearance techniques 2, 7
Trial of bronchodilators (albuterol) may be attempted to assess for bronchospasm component, though response is often limited in cystic fibrosis 2
Flexible bronchoscopy with bronchoalveolar lavage should be performed to identify bacterial pathogens and rule out anatomical abnormalities in the setting of persistent productive cough 2
Nutritional Support
Pancreatic enzyme replacement therapy (PERT) must be initiated empirically immediately given the strong clinical suspicion based on steatorrhea 2, 7, 3:
High-calorie diet targeting 120-150 kcal/kg/day to address malnutrition and promote catch-up growth 2, 7
Macronutrient balance: 8-12% protein, 40-50% carbohydrate, 40-50% fat 2, 7
Fat-soluble vitamin supplementation (A, D, E, K) is mandatory with pancreatic insufficiency 2, 7, 3
Stool studies (72-hour fecal fat collection or spot stool elastase) should be obtained to confirm fat malabsorption 2
Critical Pitfalls to Avoid
Do not label this infant as having asthma or reactive airway disease without excluding cystic fibrosis first 2. The combination of chronic productive cough, steatorrhea, and meconium ileus history makes cystic fibrosis the diagnosis until proven otherwise.
Do not attribute symptoms solely to gastroesophageal reflux 2. While GERD exists in 47-100% of infants with persistent wheezing, it does not explain the steatorrhea and failure to thrive pattern 2.
Do not delay treatment while awaiting confirmatory testing. The clinical presentation warrants immediate empiric therapy given the risk of irreversible pulmonary damage 7.
Ongoing Management After Confirmation
Immediate referral to a cystic fibrosis center for multidisciplinary care is essential once diagnosis is confirmed 2, 3
Establish chronic airway clearance regimen and antimicrobial prophylaxis protocols 2, 3
Genetic counseling for the family should be arranged 2
Regular monitoring for pulmonary function decline and bacterial colonization must be implemented 2
Aggressive nutritional rehabilitation with pancreatic enzymes titrated to stool normalization 2
Prognosis
The median age of survival for cystic fibrosis has improved to approximately 30-33 years with modern treatment 1, 7. However, respiratory failure remains the primary cause of death in >90% of patients with cystic fibrosis 7. Early diagnosis and aggressive management, particularly in patients presenting with meconium ileus, is critical for optimizing long-term outcomes 1, 6.