Diverticulitis: This condition is a common cause of sharp left lower quadrant (LLQ) pain, especially in older adults. The pain is often intermittent and can be accompanied by changes in bowel habits, fever, and nausea.

Constipation: Severe constipation can cause sharp LLQ pain due to the buildup of stool in the sigmoid colon, which is located in the left lower quadrant.
Irritable Bowel Syndrome (IBS): IBS can cause intermittent abdominal pain, including sharp LLQ pain, although the pain is often crampy and accompanied by changes in bowel habits.
Ovarian Cyst: An ovarian cyst can cause sharp LLQ pain, especially if it ruptures or torsions, although this is more common in women of reproductive age.

Ectopic Pregnancy: Although less common, an ectopic pregnancy can cause sharp LLQ pain and is a life-threatening condition that requires immediate medical attention.
Appendicitis (with atypical presentation): While appendicitis typically presents with right lower quadrant pain, it can occasionally present with LLQ pain, especially if the appendix is retrocecal.
Intestinal Obstruction: An intestinal obstruction can cause severe, intermittent abdominal pain, including sharp LLQ pain, and can lead to bowel ischemia and necrosis if not promptly treated.
Ruptured Abdominal Aortic Aneurysm: A ruptured abdominal aortic aneurysm can cause severe, sharp LLQ pain and is a life-threatening condition that requires immediate medical attention.

Inflammatory Bowel Disease (e.g., Crohn's disease, Ulcerative Colitis): These conditions can cause chronic abdominal pain, including sharp LLQ pain, although they are less common causes of intermittent pain.
Splenic Infarction: A splenic infarction can cause sharp LLQ pain, especially if the spleen is enlarged or if there is a history of sickle cell disease or other conditions that increase the risk of splenic infarction.
Left Kidney Stone: A kidney stone in the left ureter can cause sharp LLQ pain, although this is less common than other causes of LLQ pain.