A 68-year-old male musician presents to the emergency department with a sudden onset of colicky abdominal pain and massive vomiting of 4-hour duration. Examination shows an elevated WBC of 13,200 with a HCT of 45%. Electrolytes and blood urea nitrogen (BUN) are normal. An erect film of the abdomen reveals dilatation of the stomach with distended loops of bowel. What is his clinical diagnosis?

**Core Concept**
The clinical presentation of a patient with sudden onset of colicky abdominal pain, vomiting, and abdominal distension is suggestive of an intestinal obstruction. The key to diagnosis lies in the distinction between complete and incomplete obstructions, which have different clinical implications and management strategies.

**Why the Correct Answer is Right**
The patient's symptoms and examination findings are characteristic of a complete proximal intestinal obstruction. The sudden onset of colicky abdominal pain and massive vomiting indicate an obstruction at a high level, likely in the small intestine. The elevated WBC count suggests an inflammatory response, which is often seen in complete obstructions due to ischemia and bacterial overgrowth. The erect film of the abdomen reveals dilatation of the stomach with distended loops of bowel, indicating a high level of obstruction. This is consistent with a complete obstruction, where the bowel is completely blocked, leading to dilation of the proximal bowel.

**Why Each Wrong Option is Incorrect**
**Option B:** Incomplete proximal intestinal obstruction would present with less severe symptoms and may not cause significant dilation of the proximal bowel.

**Option C:** Complete ileal obstruction would present with a more distal level of obstruction, likely causing more pronounced symptoms in the lower abdomen and potentially leading to more severe electrolyte imbalances.

**Option D:** Incomplete ileal obstruction would also present with less severe symptoms and may not cause significant dilation of the bowel.

**Clinical Pearl / High-Yield Fact**
In cases of suspected intestinal obstruction, the erect film of the abdomen is a crucial diagnostic tool. A "double bubble" sign, where the stomach and duodenum are dilated and the small intestine is not visible, is highly suggestive of a complete proximal intestinal obstruction.

**✓ Correct Answer: A. Complete proximal intestinal obstruction**

✓ Correct Answer: A. Complete proximal intestinal obstruction