A 54-year-old reports vomiting blood. Tests reveal portal hypertension. Which of the following is the most likely cause of this condition?

Choice A reason:
Loss of muscle tone at the lower esophageal sphincter (LES) is the primary cause of GERD. The LES normally prevents stomach contents from refluxing into the esophagus. When its tone is reduced, acidic gastric contents can flow back, leading to symptoms such as heartburn, regurgitation, and potential damage to the esophageal lining. Factors contributing to LES dysfunction include obesity, hiatal hernia, and certain dietary habits.
Choice B reason:
Sympathetic nerve stimulation is not a cause of GERD. The autonomic nervous system plays a role in regulating digestive functions, but GERD is primarily a mechanical issue involving the LES and is not directly related to sympathetic nervous activity.
Choice C reason:
Fibrosis of the lower third of the esophagus is typically associated with conditions such as scleroderma, which can lead to esophageal motility disorders. While fibrosis might contribute to esophageal dysfunction, it is not the primary cause of GERD.
Choice D reason:
Reverse peristalsis of the stomach is not a mechanism for GERD. GERD results from dysfunction of the LES, not from the backward movement of stomach contents due to altered motility.

Choice A reason:
An embolus is the term used to describe a detached blood clot or other material that travels through the bloodstream and can cause a blockage in a blood vessel. Emboli can be composed of blood clots, fat, air, or other substances, and they can lead to serious conditions like strokes or pulmonary embolisms when they obstruct blood flow.

Choice B reason:
A thrombus is a blood clot that forms in a blood vessel and remains at its site of origin. It does not refer to a clot that has detached and is traveling through the bloodstream. The distinction between thrombus and embolus is crucial in understanding and describing vascular conditions.

Choice C reason:
Thromboembolus is a term that combines thrombus and embolus, indicating that a thrombus has become an embolus. While accurate, the more precise and commonly used term for a detached blood clot is simply "embolus."

Choice D reason:
Infarction refers to tissue death due to a lack of blood supply, often caused by an embolus or thrombus blocking a blood vessel. It does not describe the detached blood clot itself but rather the result of its action.