Differential Diagnosis

The patient's presentation of severe epigastric discomfort, especially following meals, inducing vomiting, constipation, significant weight loss, and specific physical and diagnostic findings, suggests a range of potential diagnoses. These can be categorized as follows:

• Single Most Likely Diagnosis

  • Bulimia Nervosa: The patient's behavior of inducing vomiting after meals to alleviate discomfort, along with significant weight loss, normal appetite but eating small portions, and physical signs like erosions of upper teeth (due to frequent vomiting), strongly points towards bulimia nervosa. The mild generalized tenderness and mild anemia could be secondary to malnutrition and frequent vomiting.

• Other Likely Diagnoses

  • Gastroesophageal Reflux Disease (GERD): Although the upper endoscopy revealed mild GERD, the patient's primary complaint and behavior suggest that GERD might be a contributing factor but not the primary diagnosis.
  • Functional Dyspepsia: This condition involves recurring signs and symptoms of indigestion that have no obvious cause. The patient's severe epigastric discomfort, especially after meals, could be indicative of functional dyspepsia, but the self-induced vomiting and significant weight loss are not typical.
  • Irritable Bowel Syndrome (IBS): Given the patient's constipation and abdominal discomfort, IBS could be considered. However, the inducing of vomiting and significant weight loss are not characteristic of IBS.

• Do Not Miss Diagnoses

  • Gastric Cancer: Although rare in young individuals, gastric cancer can present with weight loss, abdominal discomfort, and vomiting. It's crucial to rule out this diagnosis, especially given the patient's significant weight loss.
  • Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease or ulcerative colitis can cause chronic abdominal pain, weight loss, and changes in bowel habits. The presence of mild scratches on the joints could suggest an extraintestinal manifestation of IBD.
  • Eating Disorders with Medical Complications: Besides bulimia nervosa, other eating disorders like anorexia nervosa can lead to severe medical complications, including gastrointestinal issues, malnutrition, and significant weight loss.

• Rare Diagnoses

  • Gastroparesis: A condition where the stomach takes too long to empty its contents, which can cause nausea, vomiting, and weight loss. It's less likely given the patient's specific behaviors but could be considered if other diagnoses are ruled out.
  • Superior Mesenteric Artery Syndrome: A rare condition that causes abdominal pain, nausea, and vomiting due to compression of the duodenum between the abdominal aorta and the superior mesenteric artery. It's an unlikely diagnosis but could be considered in the context of significant weight loss and abdominal discomfort.