Differential Diagnosis for 9-Month-Old Infant with Wheezing, Labored Breathing, and Malodorous Greasy Stool

• Single Most Likely Diagnosis

  • Cystic Fibrosis: This condition is characterized by recurrent respiratory infections, wheezing, and malabsorption leading to malodorous, greasy stools due to pancreatic insufficiency. The chronic nature of symptoms and combination of respiratory and gastrointestinal findings make it a strong candidate.

• Other Likely Diagnoses

  • Asthma: Although asthma can cause wheezing and labored breathing, the presence of malodorous and greasy stools suggests a gastrointestinal component that is not typically part of asthma.
  • Gastroesophageal Reflux Disease (GERD): GERD can lead to respiratory symptoms due to aspiration, but the greasy stools are more suggestive of malabsorption.
  • Chronic Pneumonia: Could explain the respiratory symptoms but does not account for the gastrointestinal symptoms.

• Do Not Miss Diagnoses

  • Congenital Heart Disease: Certain congenital heart defects can lead to respiratory symptoms due to pulmonary congestion or decreased cardiac output. While less likely to cause greasy stools directly, the diagnosis is critical due to its potential for severe outcomes if missed.
  • Immunodeficiency: Conditions like Severe Combined Immunodeficiency (SCID) can lead to recurrent infections, including those causing respiratory symptoms, and potentially malabsorption if the gut is involved.

• Rare Diagnoses

  • Alpha-1 Antitrypsin Deficiency: A genetic disorder that can cause lung disease and liver disease, potentially leading to symptoms like those described, though it's less common in infants.
  • Shwachman-Diamond Syndrome: A rare genetic disorder characterized by exocrine pancreatic insufficiency, bone marrow dysfunction, and skeletal abnormalities, which could explain some of the symptoms.
  • Primary Ciliary Dyskinesia: A disorder of the cilia that can lead to chronic respiratory infections and potentially gastrointestinal symptoms due to the role of cilia in the gut, though it's less likely to cause greasy stools directly.