Acute pancreatitis is loosely defined as an acute inflammatory condition of the pancreas. It is one of the most common diseases of the gastrointestinal tract and in 2009 was the most common gastroenterology discharge diagnosis. Common causes include ampullary obstruction, excess consumption of alcohol, hypertriglyceridemia, hypercalcemia, infection, medication, and trauma.
Severity ranges widely. In mild cases, pancreatitis may be subclinical and not even come to medical attention, or it can be severe, sometimes necrotizing, and associated with high mortality. Primary infection is unusual, but necrosis may lead to secondary infection, abscess formation, and subsequent sepsis. Chronic complications like pseudocyst, chronic pancreatitis, or pancreatic insufficiency are not infrequent and may create a predisposition to pancreatic cancer.
Establishing the diagnosis should be straightforward. According to the American College of Gastroenterology (ACG)'s 2013 guideline on management of acute pancreatitis, acute pancreatitis is identified by the presence of at least two of the three following criteria:
- abdominal pain consistent with pancreatitis pain,
- serum amylase and/or lipase levels greater than three times the upper limit of the reference range, or
- characteristic findings from contrast-enhanced computed tomography (CECT) and/or MRI.
ACG also recommends abdominal ultrasonography to help establish the cause of pancreatitis, but pancreatic findings from ultrasound are not part of the diagnostic standard. According to the American College of Radiology's Appropriateness Criteria, the main role of ultrasound is to identify gallstones, biliary dilation, and/or choledocholithiasis, but it is not recommended for the diagnosis of pancreatitis.
Unfortunately, clinicians may not be fully aware of these ACG diagnostic criteria or may not exactly know how to interpret and apply them, causing problems down the line with coding, billing, reimbursement, compliance, and recovery auditors.
The pain associated with acute pancreatitis has very specific characteristics. It is typically epigastric or left upper quadrant in location and is usually described as constant and severe in nature, with radiation to the back, chest, or flank. From a diagnostic standpoint, clinicians should keep in mind that, as the ACG points out, pain described as dull, colicky, or located in the lower abdomen is not consistent with acute pancreatitis and suggests an alternative cause.
Clinicians also commonly hold the mistaken impression that elevation of amylase or lipase levels above the normal reference range is indicative of pancreatitis when the actual diagnostic criterion is greater than three times the upper limit. Many extrapancreatic abdominal diseases are associated with lesser degrees of elevation of these two pancreatic enzymes, including appendicitis, cholecystitis, bowel obstruction or ischemia, peptic ulcer, and gynecological disorders.
ACG's guideline recommends that CECT and MRI of the pancreas “should be reserved for patients in whom the diagnosis is unclear or who fail to improve clinically within the first 48-72 hours after hospital admission.”
Sometimes a clinician may be convinced that a patient with a marked elevation of pancreatic enzymes (greater than three times upper limit) but without significant pain and negative CECT or MRI actually has “subclinical” pancreatitis. In this situation, the clinician should document his/her reasoning, acknowledging that only one ACG diagnostic criterion is present but noting that in this particular case the patient's condition and circumstances are clinically convincing based on professional judgment.
Correct coding and billing of acute pancreatitis require an accurate diagnosis that can be clinically substantiated according to ACG guidelines, clear and consistent documentation, and specification of the cause if possible.
Diagnostic substantiation is an important regulatory, contractual, compliance, and reimbursement concept. Payers often do not accept that a patient actually has a coded condition documented by a clinician unless it can be substantiated by other qualified health care professionals based on authoritative consensus criteria, professional guidelines, evidence-based medical literature, or recognized diagnostic standards of practice that are widely accepted by the medical profession. This is why the ACG guideline diagnostic standard is so important to documentation of pancreatitis.
The International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM), provides multiple codes for acute pancreatitis that allow identification of some of the specific causes: biliary, alcoholic, drug-induced, idiopathic, a code for unspecified cause, and a catch-all code (“Other”) for any other cause specified by the clinician.
All of these codes also require identification of whether pancreatitis is associated with what ICD-10 identifies as infected necrosis, uninfected necrosis, or no associated necrosis or infection. There is no code to describe infection without necrosis, presumably because infection (including abscess) is unusual without necrosis.
Acute pancreatitis codes are all found in category K95 with fourth and fifth digits identifying the cause and the necrosis/infection distinction, respectively. To illustrate, the codes for alcoholic pancreatitis are listed in the Table. The other codes follow the same pattern with a different fourth digit to describe the cause.
Incidentally, chronic pancreatitis without any acute component has only two codes: K86.0 (alcohol-related) and K86.1 (unspecified and other specified causes or types).
In summary, the correct and compliant coding of acute pancreatitis requires clear and consistent documentation of the diagnosis that can be “clinically validated” by other qualified health care professionals. The cause is also an important diagnostic consideration to document, as well as any complicating necrosis or infection/abscess.