Differential Diagnosis for RLQ Pain in an 82 y/o Female

Single Most Likely Diagnosis

• Diverticulitis: Given the patient's age, diverticulitis is a common condition that can cause lower abdominal pain, often localized to the left lower quadrant but can sometimes present in the right lower quadrant, especially if the diverticula are located in the sigmoid colon which can be on the right side due to anatomical variations.

Other Likely Diagnoses

• Appendicitis: Although less common in the elderly, appendicitis can occur at any age and should be considered, especially if the pain is severe and accompanied by fever and vomiting.
• Ovarian Cyst or Torsion: In postmenopausal women, ovarian cysts can still occur and may cause pain if they rupture or torsion occurs.
• Urinary Tract Infection (UTI) or Pyelonephritis: Elderly individuals are more prone to UTIs, which can cause abdominal pain, and if the infection ascends to the kidneys, it can lead to pyelonephritis.
• Constipation: A common issue in the elderly that can cause significant abdominal pain and discomfort.

Do Not Miss Diagnoses

• Ectopic Pregnancy: Although highly unlikely in an 82-year-old, it's theoretically possible with assisted reproductive technologies, and missing this diagnosis could be catastrophic.
• Ruptured Abdominal Aortic Aneurysm (AAA): This condition is more common in older adults and can present with abdominal pain, although it typically is more central.
• Mesenteric Ischemia: This is a serious condition that can cause severe abdominal pain out of proportion to the physical examination findings and is more common in the elderly due to atherosclerosis.
• Intussusception: A condition where a part of the intestine telescopes into another part, which can cause bowel obstruction and ischemia, more common in children but can occur in adults.

Rare Diagnoses

• Carcinoid Tumor: A rare tumor of the neuroendocrine system that can cause abdominal pain among other symptoms.
• Malrotation with Volvulus: A rare condition where the intestine twists around its base, cutting off blood supply, more common in children but can be seen in adults.
• Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease and ulcerative colitis can cause chronic abdominal pain and are less common in the elderly but should be considered if other diagnoses are ruled out.
• Endometriosis: Although rare in postmenopausal women, especially without hormone replacement therapy, it could be considered if the patient is on estrogen replacement.