Differential Diagnosis for 29-year-old Female with Abdominal Pain

Single Most Likely Diagnosis

• Gastroesophageal Reflux Disease (GERD) or Peptic Ulcer Disease: The patient's symptoms of intermittent sharp abdominal pain that was initially relieved by Tums (an antacid) and later recurred, along with nausea and decreased appetite, are suggestive of GERD or peptic ulcer disease. The recent history of traveler's diarrhea could have contributed to the onset of these symptoms due to changes in gut flora or increased susceptibility to gastric irritation.

Other Likely Diagnoses

• Irritable Bowel Syndrome (IBS): Given the patient's recent history of traveler's diarrhea, which has now resolved, and current symptoms of bloating, nausea, and abdominal pain, IBS is a plausible diagnosis. IBS can be triggered by gastrointestinal infections.
• Functional Dyspepsia: This condition is characterized by recurring symptoms of upper abdominal discomfort or pain that are not explained by other pathologic conditions. The patient's symptoms of pain, nausea, and bloating could fit this diagnosis, especially if no other cause is found.

Do Not Miss Diagnoses

• Appendicitis: Although the patient's pain is not localized to the right lower quadrant, appendicitis can present atypically, especially in women. The severe pain and nausea warrant consideration of this diagnosis to avoid missing a potentially life-threatening condition.
• Ectopic Pregnancy: Given the patient's age and sex, ectopic pregnancy must be considered, especially if there is any chance of pregnancy. Severe abdominal pain and nausea are symptoms that could be associated with an ectopic pregnancy.
• Ovarian Torsion or Rupture: These are gynecological emergencies that can present with severe abdominal pain and nausea. A history of recent travel or changes in bowel habits does not rule out these conditions.

Rare Diagnoses

• Inflammatory Bowel Disease (IBD): While less likely given the acute onset, IBD (including Crohn's disease and ulcerative colitis) could be considered, especially if the patient has a family history or if other symptoms such as weight loss, fever, or bloody stools are present.
• Gallbladder Disease: Gallstones or cholecystitis could cause the patient's symptoms, especially if the pain is localized to the right upper quadrant or worsens after eating fatty foods. However, the absence of these specific details makes this diagnosis less likely at the moment.