Differential Diagnosis for 8-year-old with Groin and Abdominal Pain

Single most likely diagnosis

• Appendicitis: The pain starting near the belly button and radiating to the left groin could be indicative of appendicitis, especially given the severity of the pain that initially rendered the patient unable to move. Although appendicitis typically presents with pain migrating to the right lower quadrant, variations in presentation, especially in children, can occur.

Other Likely diagnoses

• Ovarian torsion or ovarian cyst: In prepubescent girls, ovarian torsion or ruptured ovarian cysts can present with severe, acute abdominal pain that may radiate to the groin. The absence of fever and the fact that the pain has somewhat resolved might make this less likely, but it remains a consideration.
• Intussusception: This condition, where a part of the intestine slides into an adjacent part, can cause severe abdominal pain, often intermittent, and may radiate to the groin. It's more common in younger children but should be considered.
• Constipation: Severe constipation can cause significant abdominal and groin pain, especially if there is a large, hard stool mass. The pain might decrease as the constipation is relieved.

Do Not Miss (ddxs that may not be likely, but would be deadly if missed)

• Testicular torsion: Although the pain has decreased and the patient is an 8-year-old, testicular torsion is a surgical emergency that can present with sudden, severe groin pain and must be ruled out promptly to preserve the testicle.
• Ectopic pregnancy: Extremely unlikely in an 8-year-old but theoretically possible in cases of precocious puberty or sexual abuse. It's crucial to consider all possibilities, no matter how rare, in the context of severe abdominal pain.
• Ruptured ectopic kidney or other renal anomalies: Rare conditions but could present with severe pain if there's an associated complication like a stone or infection.

Rare diagnoses

• Inguinal hernia: While not typically causing severe, acute pain unless incarcerated or strangulated, an inguinal hernia could potentially cause groin pain, especially if it becomes incarcerated.
• Psoas abscess: A collection of pus in the psoas muscle can cause abdominal and groin pain, usually accompanied by fever and other signs of infection, which are not prominently featured in this case.
• Sickle cell crisis: In children with sickle cell disease, a crisis can cause severe pain almost anywhere, including the abdomen and groin, due to vaso-occlusive episodes.

Each of these diagnoses should be considered in the context of the patient's full history, physical examination, and appropriate diagnostic tests to determine the underlying cause of the pain.