Gastroenterology Coding Alert

Other diseases of appendix get more accuracy from next year.

Think of a gastroenterology practice and you get visions of patients with abdominal pain. Abdominal pain most commonly translates to appendicitis, so understanding how to report appendicitis will reduce your pains in the long run after ICD-10 comes into play from next October. 

Background: Appendicitis is an inflammation of the appendix— a small, around 3 1/2-inch-long tube-like structure of tissue that extends from the large intestine. The appendix is a vestigial organ and generally has no known function. Additional diagnosis coding options include peritonitis, an inflammation of the abdominal cavity’s lining (the peritoneum). Peritonitis can be fatal unless treated quickly with antibiotics.

Appendicitis can be categorized as either acute appendicitis or other/unspecified appendicitis. The documentation is the key to discerning the difference between the different types.

Beware of Peritonitis in Acute Appendicitis 

Currently, you have to scan through the documentation to check for the presence of peritonitis, localized or generalized, before committing to a code. Based on the presence of peritonitis or absence thereof, you choose from the 540 group among the ICD-9 codes with fourth digit providing details of peritonitis:

• 540.0 -- Acute appendicitis with generalized peritonitis
• 540.1 -- Acute appendicitis with peritoneal abscess
• 540.9 -- Acute appendicitis without peritonitis

The criteria for diagnosis and coding will remain unchanged even after ICD-10 change over next year. Peritonitis will remain the deciding factor for coding acute appendicitis. Under ICD-10, code, you will have to look up the K35 group with a fourth expansion providing a clue toward the specificity of peritonitis. So, 540.0 will convert to K35.2 (Acute appendicitis with generalized peritonitis) with descriptor remaining the same. Likewise, 540.1 walks over to K35.3 (Acute appendicitis with localized peritonitis) and 540.9 crosswalks to K35.8 (Other and unspecified acute appendicitis) respectively. ICD-10 has brought in more accuracy through changes in descriptors depending on the involvement of the peritoneum (localized or generalized). Note that K35.3 is also used to report acute appendicitis with peritoneal abscess, as is done at present using 540.1 in ICD-9.

ICD-10 has further expanded K35.8 to two more codes, K35.80 (Unspecified acute appendicitis) that includes acute appendicitis without any peritonitis and acute appendicitis that is not otherwise specified (NOS) and K35.89 (Other acute appendicitis).

Other Forms of Appendicitis Get More Accuracy

If your gastro does not bring in a confirmed diagnosis of acute appendicitis, then you are left with four more codes in ICD-9 for other appendicitis conditions. The codes you can choose from currently are: 

• 541 -- Appendicitis unqualified
  
• 542 -- Other appendicitis
  
• 543.0 -- Hyperplasia of appendix (lymphoid)
  
• 543.9 -- Other and unspecified diseases of appendix
  

You don’t have to worry too much after the ICD-10 change as 541 directly crosses over to K37 (Unspecified appendicitis) and 542 walks over to K36 (Other appendicitis).

However, the two codes in group 543 have given way to six possible expansions in ICD-10 for removing generalizations and giving more accuracy to the condition. Therefore, 543.0 will change to K38.0 (Hyperplasia of appendix) and 543.9 will be represented by K38.9 (Disease of appendix, unspecified). ICD-10 has added K38.1 (Appendicular concretions), K38.2 (Diverticulum of appendix), K38.3 (Fistula of appendix) and K38.8 (Other specified diseases of appendix), which will help in narrowing the diagnosis and result in better documentation.