What is the diagnosis for a 45-year-old female with complaints of lower right abdominal pain for 1 week, with a history of Postural Orthostatic Tachycardia Syndrome (POTS) and migraines?

Differential Diagnosis for 45 F with Lower Right Abdominal Pain

Single Most Likely Diagnosis

• Appendicitis: The patient's presentation of lower right abdominal pain is a classic symptom of appendicitis, which is a common cause of acute abdominal pain in adults. The duration of pain for 1 week could indicate a more chronic or smoldering appendicitis.

Other Likely Diagnoses

• Ovarian Cyst: Given the patient's sex and the location of the pain, an ovarian cyst could be a likely cause, especially if the cyst is ruptured or torsioned.
• Constipation or Bowel Obstruction: Although less specific, constipation or a bowel obstruction could cause lower abdominal pain and should be considered, especially if the patient has a history of gastrointestinal issues.
• Diverticulitis: Inflammation of a diverticulum in the colon could cause lower abdominal pain, typically on the left side but can occur on the right in some cases.

Do Not Miss Diagnoses

• Ectopic Pregnancy: Although less likely given the patient's age and no mention of missed periods or pregnancy symptoms, ectopic pregnancy is a life-threatening condition that must be ruled out in any female patient of childbearing age presenting with lower abdominal pain.
• Ruptured Aneurysm or Vascular Emergency: A ruptured abdominal aortic aneurysm or other vascular emergencies can present with abdominal pain and are life-threatening conditions that require immediate diagnosis and treatment.
• Intestinal Ischemia: Reduced blood flow to the intestines can cause severe abdominal pain and is a medical emergency.

Rare Diagnoses

• Endometriosis: While endometriosis can cause chronic pelvic pain, it is less likely to cause acute lower right abdominal pain. However, it should be considered in the differential diagnosis, especially if the patient has a history of pelvic pain or infertility.
• Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease or ulcerative colitis can cause chronic abdominal pain and should be considered if the patient has a history of gastrointestinal symptoms or if other diagnoses are ruled out.