Differential Diagnosis for Rebound Tenderness in the LLQ The patient's presentation of 9 out of 10 rebound tenderness in the lower left quadrant (LLQ) suggests a significant abdominal pathology. The differential diagnosis can be categorized as follows:
- Single most likely diagnosis
- Appendicitis: Although appendicitis typically presents with pain in the lower right quadrant (LRQ), it can occasionally occur in the LLQ, especially if the appendix is retrocecal or has a long mesentery. The high level of rebound tenderness supports this diagnosis.
- Other Likely diagnoses
- Diverticulitis: This condition is characterized by inflammation of the diverticula in the colon, often presenting with pain in the LLQ. The rebound tenderness could be indicative of a diverticular abscess or perforation.
- Intestinal obstruction: Obstruction of the intestine can cause severe abdominal pain, nausea, vomiting, and rebound tenderness, especially if the obstruction is complete or near-complete.
- Ovarian torsion or cyst rupture: In female patients, ovarian torsion or cyst rupture can cause severe pain and rebound tenderness in the LLQ.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed)
- Ectopic pregnancy: Although less common, an ectopic pregnancy can present with abdominal pain and rebound tenderness, and is a life-threatening condition if not promptly diagnosed and treated.
- Ruptured abdominal aortic aneurysm: This is a rare but potentially fatal condition that can cause severe abdominal pain and rebound tenderness, often accompanied by hypotension and other signs of shock.
- Pneumococcal peritonitis: This is a rare but serious condition that can cause severe abdominal pain, rebound tenderness, and sepsis, often in patients with underlying medical conditions.
- Rare diagnoses
- Gastrointestinal foreign body: A foreign body in the gastrointestinal tract can cause abdominal pain, nausea, vomiting, and rebound tenderness, especially if the object is sharp or has caused a perforation.
- Inflammatory bowel disease (IBD) flare: Patients with IBD, such as Crohn's disease or ulcerative colitis, can experience exacerbations of their condition, leading to severe abdominal pain and rebound tenderness.
- Mesenteric ischemia: This is a rare condition characterized by reduced blood flow to the intestines, which can cause severe abdominal pain, rebound tenderness, and other symptoms.