What is the most likely diagnosis for a patient with a history of vomiting partially digested foods, unintentional weight loss, and poorly controlled diabetes mellitus (DM) with a past partial gastrectomy?

Gastric Outlet Obstruction (Answer: D)

The most likely diagnosis is gastric outlet obstruction (GOD) secondary to the patient's prior partial gastrectomy, given the classic presentation of postprandial vomiting of partially digested food, significant weight loss, cachexia, and radiographic evidence of gastric distention with decompressed small bowel. 1

Key Diagnostic Features Supporting GOD

The clinical presentation strongly points to mechanical obstruction rather than functional gastroparesis:

• Vomiting pattern: Emesis of partially digested food within 30 minutes of eating is characteristic of mechanical outlet obstruction, not the delayed emptying pattern typical of gastroparesis 1

• Radiographic findings: An enlarged gastric bubble with decompressed (not dilated) small intestinal loops indicates gastric retention with normal distal bowel, pathognomonic for gastric outlet obstruction 1

• Surgical history: Partial gastrectomy at age 52 creates significant risk for anastomotic stricture, adhesions, or marginal ulceration causing mechanical obstruction 1

• Absence of nausea: The lack of significant nausea before vomiting is more consistent with mechanical obstruction than gastroparesis, where nausea is typically prominent 1, 2

• Severe cachexia and weight loss: The 30-pound weight loss over 6 months with BMI of 17 and temporal wasting indicates severe nutritional compromise from near-complete obstruction 1

Why Not Gastroparesis?

While the patient has poorly controlled diabetes (HbA1c 8.9%), several features argue against diabetic gastroparesis as the primary diagnosis:

• Gastroparesis typically presents with prominent nausea, early satiety, and bloating - this patient lacks significant nausea 1, 3, 2

• Gastroparesis affects 20-40% of diabetics, primarily those with long-standing type 1 diabetes and other complications - the question doesn't specify diabetes type or duration 1

• The radiographic pattern is wrong: Gastroparesis would show a dilated, atonic stomach without the characteristic decompressed small bowel pattern seen here 1

• Gastroparesis requires exclusion of mechanical obstruction before diagnosis - this fundamental principle from AGA guidelines mandates ruling out GOD first 1, 4

Critical Diagnostic Algorithm

Before confirming gastroparesis, guidelines mandate:

1. Esophagogastroduodenoscopy (EGD) or barium study to exclude mechanical gastric outlet obstruction or peptic ulcer disease 1

2. Only after mechanical causes are excluded should gastric emptying scintigraphy be performed to diagnose gastroparesis 1, 4

3. In post-surgical patients, anastomotic stricture, marginal ulceration, and adhesions must be ruled out before attributing symptoms to gastroparesis 1

Why Not the Other Options?

• Small bowel obstruction (A): Would show dilated small bowel loops, not decompressed ones 1

• Esophageal stricture (C): Would present with dysphagia to solids progressing to liquids, not postprandial vomiting of partially digested food 1

• Cholelithiasis (E): Presents with right upper quadrant pain, not postprandial vomiting and cachexia 1

Clinical Pitfall

The most common error is attributing all upper GI symptoms in diabetics to gastroparesis without first excluding mechanical obstruction. 1 The presence of diabetes does not exclude concurrent mechanical pathology, especially in patients with prior gastric surgery. The AGA explicitly states that gastroparesis is a diagnosis of exclusion requiring absence of obstructing structural lesions. 1