A patient is admitted to the hospital after ingesting lye. The following day he complains of chest pain. His pulse is 120 bpm. On physical examination he is found to have subcutaneous crepitus on palpation. His chest x-ray shows widening of the mediastinum and a pleural effusion. What has occurred?

**Core Concept**
The patient has ingested a caustic substance (lye), which has caused severe esophageal and mediastinal damage, leading to a mediastinitis and subsequent complications.

**Why the Correct Answer is Right**
The ingestion of lye causes severe alkaline burns to the esophagus and surrounding tissues, leading to a necrotizing esophagitis and mediastinitis. The subcutaneous crepitus on palpation is a result of gas formation due to the bacterial fermentation of necrotic tissue. The widening of the mediastinum on chest x-ray is indicative of the mediastinitis, which is an infection of the tissues in the mediastinum. The pleural effusion is a result of the inflammation and infection spreading to the pleural space.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not accurately describe the complications of lye ingestion. The patient's symptoms and signs are not typical of a simple esophageal stricture.
**Option B:** This option is incorrect because it is more typical of a pulmonary embolism, which would not cause subcutaneous crepitus or a pleural effusion.
**Option C:** This option is incorrect because it does not accurately describe the complications of lye ingestion. The patient's symptoms and signs are not typical of a simple gastroesophageal reflux disease (GERD).

**Clinical Pearl / High-Yield Fact**
Lye ingestion is a medical emergency that requires prompt treatment, including endoscopy and esophageal dilation, as well as broad-spectrum antibiotics to treat the mediastinitis.

**Correct Answer: D. Esophageal rupture and subsequent mediastinitis.**

✓ Correct Answer: C. Esophageal perforation