Differential Diagnosis for Sharp Abdominal RLQ Pain Relieved by Localized Pressure

• Single Most Likely Diagnosis
  • Appendicitis: The sharp pain in the right lower quadrant (RLQ) that is relieved by localized pressure is highly suggestive of appendicitis, especially if the pain initially started around the navel and then moved to the RLQ. The relief with localized pressure could indicate a localized peritonitis or an appendiceal mass that is partially contained, reducing the pain when pressure is applied.
• Other Likely Diagnoses
  • Ovarian Cyst or Torsion: In females, ovarian cysts or torsion can cause sharp RLQ pain. The pain might be relieved by localized pressure if the cyst is small or if the torsion is intermittent.
  • Intestinal Obstruction: Early stages of intestinal obstruction can cause sharp, intermittent pain that might be relieved by localized pressure, although this is less common.
  • Mesenteric Lymphadenitis: This condition, often seen in children and young adults, involves inflammation of the lymph nodes in the mesentery and can mimic appendicitis, with pain that might be relieved by pressure.
• Do Not Miss Diagnoses
  • Ectopic Pregnancy: Although less likely, ectopic pregnancy is a critical diagnosis to consider in females of childbearing age, as it can present with sharp, unilateral lower abdominal pain. The pain might be relieved by localized pressure but can rapidly escalate.
  • Ruptured Aneurysm or Aortic Dissection: While these conditions typically present with back or mid-abdominal pain, in rare cases, they can cause RLQ pain if the dissection or rupture involves branches that affect the right lower quadrant.
  • Diverticulitis: Although more common on the left side, diverticulitis can occur on the right and cause severe pain that might be relieved by localized pressure.
• Rare Diagnoses
  • Right Lower Quadrant Pancreatitis: Pancreatitis usually causes mid-abdominal pain radiating to the back, but in rare cases, especially with a pancreatic tail lesion, it can cause RLQ pain.
  • Retrocecal Appendicitis: While not rare, the presentation can be atypical, with the pain sometimes being more diffuse or relieved by certain positions or localized pressure due to the retrocecal location of the appendix.
  • Inflammatory Bowel Disease (IBD) Flare: IBD, such as Crohn's disease or ulcerative colitis, can cause sharp abdominal pain that might be relieved by localized pressure during a flare, although this is less common in the RLQ.