The Revised Atlanta Classification for acute pancreatitis assesses the severity of the condition based on user input regarding local or systemic complications and organ failure. The process involves evaluating two main inputs and determining the severity of acute pancreatitis (AP) by categorizing it as mild, moderate, or severe.

Inputs required are:

1. Local or systemic complications (such as pancreatic necrosis) with options:
   - Absent
   - Present

2. Organ failure with options:
   - Absent
   - Transient (resolving in <= 48 hours)
   - Persistent (> 48 hours; single or multiple)

The inputs are evaluated using a logic-based computation to result in one of the three categories of acute pancreatitis:

- Mild AP: Characterized by the absence of both local or systemic complications and organ failure. This is determined if local or systemic complications are absent and organ failure is absent (A and C).

- Moderate AP: Defined by the presence of local or systemic complications with no organ failure or transient organ failure, or when complications are absent but organ failure is transient. This is assessed when local or systemic complications are present, and organ failure is absent or transient (B and (C or D)); or when complications are absent and organ failure is transient (A and D).

- Severe AP: Identified by the presence of persistent organ failure, irrespective of local or systemic complications. This is recognized when organ failure is persistent (E).

In computation:

- If localOrSystemicComplications is absent and organFailure is absent, the result is Mild AP.
- If localOrSystemicComplications is present and organFailure is absent or transient, or if localOrSystemicComplications is absent and organFailure is transient, the result is Moderate AP.
- If organFailure is persistent, the result is Severe AP.

If all decision conditions are unmet, the output prompts the user to make a selection for all inputs as a result, signaling a missing or incorrect input configuration.

The system systematically evaluates the combination of inputs to place the condition in the appropriate category, thus informing about the severity level of acute pancreatitis. Here is the summary in a table format for clarity:

| Local or Systemic Complications | Organ Failure                        | Result     |
|--------------------------------|-------------------------------------|------------|
| Absent                          | Absent                              | Mild AP    |
| Present                         | Absent or Transient                 | Moderate AP|
| Absent                          | Transient                           | Moderate AP|
| Any                             | Persistent                          | Severe AP  |

The Revised Atlanta Classification for Acute Pancreatitis is a clinical scoring system used to classify the severity of acute pancreatitis. This classification system is applicable to patients who present with symptoms suggestive of acute pancreatitis, such as abdominal pain, nausea, vomiting, and elevated levels of pancreatic enzymes in the blood.

The Revised Atlanta Classification provides a standardized approach to stratify patients into different severity levels based on clinical and imaging findings. It categorizes acute pancreatitis into two phases: early (first week) and late (after the first week), and further classifies the disease into mild, moderately severe, and severe. This classification helps in predicting the clinical course, management, and prognosis of the disease.

The clinical utility of this calculator lies in its ability to guide clinicians in making decisions about the appropriate level of care, potential need for interventions, and to predict patient outcomes. It also aids in communication between healthcare providers and in research settings.

There are no specific exclusion criteria for the use of the Revised Atlanta Classification. However, it should be noted that it is not designed to diagnose acute pancreatitis, but rather to classify the severity of the disease in patients in whom a diagnosis of acute pancreatitis has already been established based on clinical, laboratory, and imaging findings.

Revised Atlanta classification for acute pancreatitis