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Differential Diagnosis for Right Lower Quadrant (RLQ) Pain with Appendicitis Ruled Out

Single Most Likely Diagnosis

  • Mesenteric Lymphadenitis: This condition is often considered the most likely diagnosis after appendicitis has been ruled out, especially in children and young adults. It presents with similar symptoms to appendicitis, including RLQ pain, and is usually caused by a viral infection.

Other Likely Diagnoses

  • Ovarian Cyst or Torsion: In females, ovarian cysts or torsion can cause severe RLQ pain. The pain can be sudden and may be accompanied by nausea and vomiting.
  • Ectopic Pregnancy: Although less common, ectopic pregnancy should be considered in females of childbearing age presenting with RLQ pain, especially if there's a possibility of pregnancy.
  • Diverticulitis: While more common on the left side, diverticulitis can occur on the right side and cause RLQ pain, especially in individuals with right-sided diverticula.
  • Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease or ulcerative colitis can cause chronic or acute RLQ pain, depending on the location and severity of the disease.

Do Not Miss Diagnoses

  • Intussusception: A condition where a part of the intestine telescopes into another, which can cause severe abdominal pain, vomiting, and bloody stools. It's more common in children but can occur in adults.
  • Volvolus: A twisting of a portion of the intestine that can cut off blood supply, leading to tissue death. It's a surgical emergency.
  • Hernias: Incarcerated or strangulated hernias can cause severe pain and require immediate surgical intervention.
  • Pneumonia: Basilar pneumonia, especially if involving the right lower lobe, can refer pain to the RLQ.

Rare Diagnoses

  • Meckel's Diverticulum: A congenital anomaly of the small intestine that can cause pain, bleeding, or obstruction, typically in the RLQ.
  • Retrocecal Appendicitis: Although appendicitis has been ruled out, a retrocecal appendix (located behind the cecum) might not always present with the classic symptoms and could be considered if other diagnoses are excluded.
  • Yersinia Ileitis: A rare bacterial infection that can mimic appendicitis, causing RLQ pain and intestinal inflammation.
  • Carcinoid Tumors: Rare tumors that can cause abdominal pain, flushing, and diarrhea, depending on their location and secretion of serotonin.

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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