A patient presents with dysphagia of 4 weeks duration. Now he is able to swallow liquid food only. Which of the following is the one investigation to be done?
**Core Concept**
The patient's presentation of dysphagia, particularly the progression to difficulty swallowing liquids, suggests an esophageal obstruction or motility disorder. The primary goal of initial investigation is to identify the cause and location of the obstruction.
**Why the Correct Answer is Right**
Esophagogastroduodenoscopy (EGD) is a crucial investigation in this scenario. It allows for direct visualization of the esophageal mucosa, identification of any strictures or tumors, and biopsy of suspicious lesions. Additionally, EGD can assess esophageal motility and rule out other causes of dysphagia such as esophagitis or gastritis. The procedure can also aid in the placement of dilators or stents if necessary.
**Why Each Wrong Option is Incorrect**
**Option A:** Upper GI series (barium swallow) may be useful in detecting structural abnormalities, but it does not provide the same level of detail as EGD for mucosal assessment and biopsy.
**Option B:** CT scan of the thorax can help identify extraluminal causes of dysphagia, such as mediastinal tumors or lymphadenopathy, but it is not the first-line investigation for esophageal pathology.
**Option C:** Manometry is a useful tool for assessing esophageal motility disorders, but it is typically used after initial imaging has been performed to guide further management.
**Clinical Pearl / High-Yield Fact**
In cases of suspected esophageal obstruction or dysphagia, EGD is often the investigation of choice due to its ability to provide both diagnostic and therapeutic options.
**Correct Answer: C. Esophagogastroduodenoscopy (EGD).**