Differential Diagnosis for a 10-year-old Boy with Bright Red Blood Stained Stools

Single Most Likely Diagnosis

• Anal Fissure: The presence of bright red blood stained stools without fever or pain abdomen, along with the specific mention of anal fissure, makes this the most likely diagnosis. Anal fissures are a common cause of rectal bleeding in children, especially if they are associated with constipation or hard stools that can cause a tear in the anal mucosa.

Other Likely Diagnoses

• Constipation with Rectal Bleeding: Constipation can lead to hard stools that may cause rectal bleeding due to the strain during bowel movements. This is a common issue in children and can be associated with bright red blood.
• Hemorrhoids: Though less common in children, hemorrhoids can cause bright red blood per rectum, especially if they are thrombosed or prolapsed.
• Infectious Gastroenteritis: While the question specifies no fever, some cases of infectious gastroenteritis can present with minimal or no systemic symptoms, leading to bloody stools due to the infection.

Do Not Miss Diagnoses

• Intussusception: Although it typically presents with abdominal pain, vomiting, and currant jelly stool (a mixture of blood and mucus), intussusception can occasionally present with painless, bright red rectal bleeding. It's a medical emergency that requires prompt diagnosis and treatment.
• Meckel's Diverticulum: This congenital anomaly can cause painless, bright red rectal bleeding due to the presence of ectopic gastric mucosa that can lead to ulceration and bleeding. It's a critical diagnosis not to miss due to the potential for significant blood loss.
• Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease and ulcerative colitis can present with rectal bleeding, although they are typically accompanied by other symptoms such as diarrhea, weight loss, and abdominal pain.

Rare Diagnoses

• Juvenile Polyps: These are benign growths in the colon that can cause rectal bleeding, usually painless and intermittent. They are more common in younger children.
• Vascular Malformations: Rare conditions like arteriovenous malformations can cause rectal bleeding due to abnormal blood vessel structures in the gastrointestinal tract.
• Trauma: Accidental or non-accidental trauma to the rectum or anus can cause bleeding, though this would typically be associated with a clear history of injury.