Differential Diagnosis for Left-Sided Abdominal Pain

The patient's presentation of left-sided abdominal pain that is cramping, sharp, and constant, without radiation to the back or flank, and not worsened by eating, suggests several potential diagnoses. The differential diagnosis can be categorized as follows:

• Single Most Likely Diagnosis

  • Diverticulitis: This condition is characterized by inflammation of a diverticulum in the colon, which can cause left-sided abdominal pain. The pain's description and location, along with the absence of symptoms like nausea, vomiting, or fever, make diverticulitis a plausible diagnosis, especially given the patient's age and the nature of the pain.

• Other Likely Diagnoses

  • Irritable Bowel Syndrome (IBS): Given the initial episode of diarrhea and the nature of the pain, IBS could be considered, especially if the patient has a history of similar gastrointestinal symptoms.
  • Constipation: Although the patient denies current diarrhea, constipation could cause left-sided abdominal pain, especially if the pain is exacerbated by movement.
  • Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease or ulcerative colitis could present with abdominal pain, although they typically have additional symptoms like diarrhea, weight loss, or blood in the stool.

• Do Not Miss Diagnoses

  • Ectopic Pregnancy: Although the patient is male, it's essential to consider ectopic pregnancy in any patient presenting with abdominal pain, as it can be life-threatening. However, given the patient's gender, this is extremely unlikely.
  • Appendicitis: While appendicitis typically presents with right lower quadrant pain, it can occasionally present atypically, especially if the appendix is retrocecal. It's crucial to consider appendicitis due to its potential for serious complications if not promptly treated.
  • Ovarian Torsion: Again, given the patient's gender, this is not applicable but would be a critical diagnosis to consider in female patients.
  • Testicular Torsion: This condition, although more commonly associated with testicular pain, could potentially cause lower abdominal pain and is a medical emergency.

• Rare Diagnoses

  • Intussusception: A condition where a part of the intestine slides into an adjacent part, which can cause abdominal pain, is more common in children but can occur in adults.
  • Mesenteric Ischemia: This condition involves insufficient blood flow to the intestines and can cause severe abdominal pain. It's more common in older adults or those with cardiovascular disease.
  • Splenic Infarction: Although rare, splenic infarction can cause left upper quadrant pain and could be considered if the patient has a history of sickle cell disease, thrombocytosis, or other conditions that predispose to splenic infarction.

Each of these diagnoses should be considered in the context of the patient's full clinical presentation, including history, physical examination, and diagnostic tests as appropriate.