Differential Diagnosis for Left Lower Quadrant Pain

Single Most Likely Diagnosis

• Diverticulitis: This is the most common cause of left lower quadrant pain, especially in older adults. It occurs when diverticula in the colon become inflamed, leading to pain, tenderness, and potentially serious complications if not treated.

Other Likely Diagnoses

• Constipation: Constipation can cause left lower quadrant pain due to the accumulation of stool in the sigmoid colon, which is located in the left lower quadrant.
• Irritable Bowel Syndrome (IBS): IBS can cause abdominal pain, including left lower quadrant pain, due to altered bowel habits and sensitivity.
• Ovarian Cyst or Torsion: In women, ovarian cysts or torsion can cause left lower quadrant pain, especially if the cyst is large or has ruptured.
• Kidney Stone: A kidney stone in the left ureter can cause severe left lower quadrant pain, often radiating to the groin.

Do Not Miss Diagnoses

• Ectopic Pregnancy: Although less common, an ectopic pregnancy can cause left lower quadrant pain and is a life-threatening condition if not promptly diagnosed and treated.
• Appendicitis (atypical presentation): While appendicitis typically presents with right lower quadrant pain, it can occasionally present with left lower quadrant pain, especially if the appendix is retrocecal.
• Intestinal Obstruction: An intestinal obstruction can cause left lower quadrant pain, nausea, vomiting, and constipation, and is a medical emergency if not promptly treated.
• Inflammatory Bowel Disease (IBD): IBD, such as Crohn's disease or ulcerative colitis, can cause left lower quadrant pain, diarrhea, and weight loss, and requires prompt diagnosis and treatment to prevent complications.

Rare Diagnoses

• Colonic Cancer: Although rare, colonic cancer can cause left lower quadrant pain, especially if the tumor is large or has metastasized.
• Endometriosis: Endometriosis can cause left lower quadrant pain, especially during menstruation, due to the growth of endometrial tissue outside the uterus.
• Inferior Mesenteric Artery Occlusion: This rare condition occurs when the inferior mesenteric artery becomes occluded, causing left lower quadrant pain, nausea, and vomiting.
• Splenic Infarction: A splenic infarction can cause left lower quadrant pain, especially if the spleen is enlarged or has ruptured.