Differential Diagnosis for 37-year-old Female with Six Days of Right Iliac Fossa (RIF) Pain and Nausea
Single Most Likely Diagnosis
- Constipation: Given the normal laboratory and imaging findings, constipation is a common cause of abdominal pain and nausea, especially if the patient has not had a bowel movement recently or is experiencing hard stools.
Other Likely Diagnoses
- Irritable Bowel Syndrome (IBS): This condition can cause chronic or intermittent abdominal pain, often accompanied by nausea and changes in bowel habits. The normal investigations do not rule out IBS.
- Gastroenteritis: Although the patient's white cell count (WCC) and C-reactive protein (CRP) are normal, viral gastroenteritis could still be a cause, especially if the onset was sudden and accompanied by nausea.
- Ovarian Cyst: While the ultrasound is reported as normal, small cysts or those not causing significant impedance on the ultrasound might still cause pain, especially if they are functioning or have undergone torsion not evident on the provided imaging.
Do Not Miss Diagnoses
- Ectopic Pregnancy: Although less likely given the patient's presentation and normal ultrasound, ectopic pregnancy is a life-threatening condition that must be considered, especially if there's any chance the patient could be pregnant.
- Appendicitis: Early appendicitis might not always present with elevated WCC or CRP, and a normal urinalysis does not rule out this diagnosis. Appendicitis can be a surgical emergency.
- Diverticulitis: If the patient has diverticula in the sigmoid colon, which is on the left side but can sometimes refer pain to the right, diverticulitis could be a consideration, especially if the patient is older or has risk factors.
Rare Diagnoses
- Intussusception: A condition where a part of the intestine slides into an adjacent part, which can cause intermittent abdominal pain and is more common in children but can occur in adults.
- Mesenteric Lymphadenitis: Inflammation of the lymph nodes in the mesentery, which can mimic appendicitis and might not always show abnormal lab values or specific findings on ultrasound.
- Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease or ulcerative colitis can present with chronic abdominal pain, nausea, and normal initial investigations, especially if the disease is mild or in early stages.