Differential Diagnosis for a 6-year-old with Constipation and Abdominal Pain

Single Most Likely Diagnosis

• Functional Constipation: This is the most common cause of constipation and abdominal pain in children. The patient's past medical history of constipation and the current presentation of constipation and abdominal pain for 4 days support this diagnosis. Functional constipation is a diagnosis of exclusion, but given the chronic nature of the patient's symptoms, it is a reasonable starting point.

Other Likely Diagnoses

• Gastroenteritis: Although the primary complaint is constipation, some forms of gastroenteritis can present with abdominal pain and changes in bowel habits, including constipation, especially if the child is not vomiting.
• Lactose Intolerance or Other Dietary Intolerances: These can cause abdominal pain and changes in bowel habits, including constipation, in some cases, depending on the specific intolerance and the child's diet.
• Urinary Tract Infection (UTI): UTIs can cause abdominal pain and, in some cases, changes in urinary habits that might be mistaken for constipation symptoms.

Do Not Miss Diagnoses

• Intussusception: Although more common in younger children, intussusception can occur in a 6-year-old and presents with abdominal pain (often intermittent) and possibly changes in bowel habits. It's a surgical emergency.
• Appendicitis: While less common in this age group, appendicitis can present with abdominal pain and changes in bowel habits. It's crucial to consider, especially if the pain is localized to the right lower quadrant.
• Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease and ulcerative colitis can present with chronic constipation, abdominal pain, and other systemic symptoms. Early diagnosis is crucial for management.

Rare Diagnoses

• Hirschsprung's Disease: Typically diagnosed in infancy, but in some cases, it might not be diagnosed until later in childhood. It involves an aganglionic segment of the colon leading to severe constipation.
• Spinal Cord Lesions or Tumors: These can cause neurogenic bowel, leading to constipation among other symptoms. They are rare but important to consider in the differential diagnosis.
• Endocrine Disorders (e.g., Hypothyroidism): Certain endocrine disorders can cause constipation as a symptom. While rare, they are important to rule out, especially if other systemic symptoms are present.