Ten days after Splenectomy for blunt abdominal trauma, a 23- year-old man complains of upper abdominal and lower chest pain exacerbated by deep breathing. He is anorectic but ambulatory and otherwise making satisfactory progress. On examination his temperature is 38.20C and he has decreased breath sounds at left lung base. His abdominal wound appears to be healing well, bowel sounds are active and there are no peritoneal signs. Digital rectal examination is negative. WBC 12,500/mm3 with a shift to left. CXR show ‘plate like’ atelectasis of the left lung field. Abdominal radiograph shows a non-specific gas pattern in bowel and an air-fluid level in LUQ. Serum Amylase is 150 Somogyi units per dL. The most likely diagnosis is:

**Core Concept**
The patient presents with symptoms and signs suggestive of a post-surgical complication, specifically a diaphragmatic injury or a complication related to the spleen's removal, which needs to be differentiated from other possible causes of abdominal pain and respiratory distress.

**Why the Correct Answer is Right**
The patient's symptoms and signs, including upper abdominal and lower chest pain exacerbated by deep breathing, fever, and decreased breath sounds at the left lung base, are highly suggestive of a diaphragmatic injury or a diaphragmatic hernia. The presence of a 'plate-like' atelectasis on the chest radiograph and an air-fluid level in the left upper quadrant (LUQ) on the abdominal radiograph further support this diagnosis. The patient's recent history of splenectomy for blunt abdominal trauma increases the likelihood of a diaphragmatic injury.

**Why Each Wrong Option is Incorrect**
**Option A:** This option does not provide a plausible explanation for the patient's symptoms and signs. A gastrointestinal issue, such as pancreatitis, could cause abdominal pain but would not explain the respiratory symptoms or the specific radiographic findings.

**Option B:** This option is incorrect because pancreatitis, while possible, would not explain the patient's respiratory symptoms or the specific radiographic findings.

**Option C:** This option is incorrect because a peptic ulcer would not explain the patient's respiratory symptoms or the specific radiographic findings.

**Clinical Pearl / High-Yield Fact**
A diaphragmatic hernia can occur after splenectomy, particularly if the spleen was removed for blunt abdominal trauma. It is essential to consider this diagnosis in patients with respiratory symptoms and signs after abdominal surgery.

**Correct Answer:** D. Diaphragmatic hernia. Diaphragmatic hernia is the most likely diagnosis in this patient, given the symptoms and signs of respiratory distress, abdominal pain, and the specific radiographic findings.

✓ Correct Answer: A. Subphrenic abscess