Differential Diagnosis for Left Upper and Lower Quadrant Pain

The patient presents with left upper and lower quadrant pain and pressure radiating to the side, diffuse tenderness, recent loose bowel movements, and no blood in urine. Here's a categorized differential diagnosis:

• Single Most Likely Diagnosis

  • Constipation or Gastroenteritis: Given the symptoms of loose bowel movements and abdominal pain, these conditions are common and can cause the described symptoms. The absence of blood in urine and the nature of the pain suggest a gastrointestinal issue rather than a urinary tract problem.

• Other Likely Diagnoses

  • Diverticulitis: Inflammation of the diverticula in the colon can cause left lower quadrant pain, changes in bowel habits, and tenderness. It's a common condition, especially in older adults.
  • Irritable Bowel Syndrome (IBS): While IBS can cause a variety of symptoms including abdominal pain and changes in bowel habits, it typically doesn't cause diffuse tenderness. However, it's a common condition and should be considered.
  • Kidney Stone: Although the patient reports no blood in urine, small stones might not always cause hematuria. The pain from a kidney stone can radiate and cause significant discomfort.

• Do Not Miss Diagnoses

  • Appendicitis: Although the pain is on the left side, which is less common for appendicitis, it's crucial not to miss this diagnosis due to its potential for serious complications if not treated promptly.
  • Ectopic Pregnancy: In women of childbearing age, an ectopic pregnancy can present with abdominal pain and could be life-threatening if not recognized early.
  • Intestinal Obstruction: This condition can cause severe abdominal pain, changes in bowel habits, and tenderness. It requires immediate medical attention.
  • Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease or ulcerative colitis can cause chronic abdominal pain, changes in bowel habits, and weight loss. They are important to diagnose due to their chronic nature and potential complications.

• Rare Diagnoses

  • Ovarian Torsion: A rare condition where the ovary twists around its ligaments, cutting off blood supply. It causes severe pain and is a surgical emergency.
  • Splenic Infarction or Rupture: These conditions can cause left upper quadrant pain and are more common in individuals with certain underlying conditions like sickle cell disease or trauma.
  • Pancreatitis: Inflammation of the pancreas can cause severe abdominal pain that radiates to the back and is associated with nausea, vomiting, and changes in bowel habits. It's less common but serious.