**Question:** Investigation of choice for Acute pancreatitis: September 2005 & 2006

**Core Concept:** Acute pancreatitis is an inflammation of the pancreas, typically triggered by gallstones, alcohol consumption, or other causes. The diagnosis involves a combination of clinical assessment and appropriate investigations.

**Why the Correct Answer is Right:**

Acute pancreatitis is a clinical diagnosis, but certain investigations help confirm the diagnosis and guide management. In the context of the question, the correct answer is:

**Correct Answer:** D. Abdominal ultrasound

**Why Each Wrong Option is Incorrect:**

A. Blood tests (e.g., amylase and lipase) are useful for confirming the diagnosis but are not considered the investigation of choice. They may be normal in early stages or if the patient has hyperglycaemic stress response.

B. Computed tomography (CT) scan is important, but it is an advanced investigation and may not be readily available in all centers or may expose the patient to ionizing radiation.

C. Serum lipase and amylase levels help confirm the diagnosis but are not the investigation of choice, as mentioned above.

**Why Abdominal Ultrasound is Right:** Abdominal ultrasound is a non-invasive, readily available, and radiation-free imaging modality that can demonstrate acute pancreatitis by showing pancreatic enlargement, fluid collections (peripancreatic fluid), and gallstones (which are often the cause of acute pancreatitis).

**Clinical Pearl:** In clinical practice, a combination of a thorough clinical examination, blood tests, and abdominal ultrasound can lead to a definitive diagnosis of acute pancreatitis and guide management. In certain cases, further investigations like CT or MRI may be required.

**Core Concept:** Acute pancreatitis is a clinical diagnosis, but confirmatory tests and imaging modalities can help guide management. Abdominal ultrasound is a readily available, non-invasive, and radiation-free imaging modality that can demonstrate the key features of acute pancreatitis.