Differential Diagnosis for a 5-month-old Male with Weight Faltering and Severe Normocytic Anemia
- Single Most Likely Diagnosis
- Hirschsprung's Disease: Given the clinical presentation of severe constipation (as suggested by the need for a rectal enema) and failure to thrive, Hirschsprung's disease is a strong consideration. The disease is characterized by the absence of ganglion cells in the distal bowel, leading to functional obstruction.
- Other Likely Diagnoses
- Celiac Disease: Although less directly linked to the symptoms of constipation and anemia, celiac disease can cause malabsorption leading to failure to thrive and anemia due to iron deficiency or folate/vitamin B12 deficiency.
- Cow's Milk Protein Allergy (CMPA): Initially suspected, CMPA can cause gastrointestinal symptoms, including diarrhea or constipation, and failure to thrive. However, the presence of severe anemia and constipation might suggest other diagnoses are more likely.
- Infectious Enteritis: Chronic infection could lead to malabsorption and failure to thrive. The presence of parainfluenza and rhinovirus might indicate a predisposition to infections, but the specific symptoms suggest a more chronic condition.
- Do Not Miss Diagnoses
- Intestinal Obstruction: Conditions like intussusception or volvulus could present with abdominal distress and failure to pass stool, mimicking Hirschsprung's disease but requiring urgent surgical intervention.
- Neurological Disorders: Conditions affecting the enteric nervous system, such as chronic intestinal pseudo-obstruction, could mimic Hirschsprung's disease but have different management strategies.
- Chronic Infections (e.g., TB): Although rare in this context, chronic infections could cause similar symptoms and would require specific treatment.
- Rare Diagnoses
- Congenital Sucrase-Isomaltase Deficiency: A rare genetic disorder leading to malabsorption of carbohydrates, which could result in failure to thrive and gastrointestinal symptoms.
- Autoimmune Enteropathy: A rare condition characterized by autoimmune destruction of the intestinal lining, leading to severe diarrhea, malabsorption, and failure to thrive.
- Mitochondrial Disorders: Certain mitochondrial disorders can affect the gastrointestinal system, leading to chronic diarrhea, constipation, or intestinal pseudo-obstruction, and failure to thrive.
Each of these diagnoses should be considered in the context of the patient's overall clinical presentation, and diagnostic testing should be tailored to confirm or rule out these conditions as appropriate.