Gastroenterology Coding Alert

Knowing your way around the K57.- codes is key.

Diverticulosis and diverticulitis have their fair share of similarities: they are both types of diverticular disease, they both involve abnormal pouches in the bowel wall, and their names both measure in at a whopping six syllables.

Though they may have commonalities, diverticulosis and diverticulitis are distinct in their own ways. As a result, the ICD-10-CM code set contains different codes for diverticulosis and diverticulitis.

Coding mistakes with diverticulosis and diverticulitis are common for even experienced gastroenterology coders, but keeping a few best practices in mind can simplify coding diverticular disease.

Here are some tips for keeping diverticulosis and diverticulitis straight and navigating the codes designated for the two diseases.

Find out How Diverticulosis and Diverticulitis Differ

Diverticulosis is a condition common in older adults characterized by diverticula (small pouches) in the intestinal wall without any signs of inflammation. While most patients with diverticulosis do not have symptoms, symptomatic patients may experience mild pain or constipation, or in some cases, diverticular bleeding.

Diverticulosis progresses to diverticulitis when there is inflammation in at least one diverticulum; this often occurs due to a bacterial infection. Diverticulitis can cause pain and complications. Diverticulitis symptoms include fever, nausea and vomiting, bloating, and bowel changes.

Uncomplicated diverticulitis can resolve on its own, but complications may indicate a need for medication or surgery. Complicated diverticulitis involves abscess formation and perforation.

Turn to K57.- Codes for Diverticular Disease

The 10^th edition of the ICD-10-CM code set lists eight codes for diverticular disease:

• K57.0- (Diverticulitis of small intestine with perforation and abscess)
• K57.1- (Diverticular disease of small intestine without perforation or abscess)
• K57.2- (Diverticulitis of large intestine with perforation and abscess)
• K57.3- (Diverticular disease of large intestine without perforation or abscess)
• K57.4- (Diverticulitis of both small and large intestine with perforation and abscess)
• K57.5- (Diverticular disease of both small and large intestine without perforation or abscess)
• K57.8- (Diverticulitis of intestine, part unspecified, with perforation and abscess)
• K57.9- (Diverticular disease of intestine, part unspecified, without perforation or abscess)

Recognize These Diverticular Disease Coding Tips

When applicable, use an appropriate K65.- (Peritonitis) code alongside any of the K57.- codes, as instructed by the Code also note under the K57.- parent code.

Keep in mind that each of the K57.- codes has subcodes that specify more details about the patient’s condition and allow for more accurate coding. You will not use any of the K57.- codes listed above for reimbursement purposes, because each of those codes require a 5^th character to complete the code. Instead, use the code listed under the appropriate K57.- code that best fits the patient’s condition.

The 5^th character indicates whether a patient has a perforation, an abscess, or bleeding (or some combination of one or two of these conditions).

Perforation occurs when a diverticulum becomes so inflamed and swollen that it tears open. This complication of diverticulitis is an emergency because a ruptured diverticulum can lead to sepsis if intestinal bacteria leaks into the peritoneal cavity.

People diagnosed with diverticulitis may develop a pus-filled lump, also known as an abscess, outside of their intestinal lining. Clinicians typically use antibiotic medication or a percutaneous drainage procedure to treat abscesses depending on the size and severity of the infection.

Example: You’ll assign K57.00 (Diverticulitis of small intestine with perforation and abscess without bleeding) for a patient diagnosed with diverticulitis of the small intestine with perforation and abscess, but no bleeding; and you’ll use K57.01 (Diverticulitis of small intestine with perforation and abscess with bleeding) for a patient diagnosed with diverticulitis of the small intestine with perforation, abscess, and bleeding.

Be Careful to Avoid Common Dx Coding Mistakes

There are many exclusions for the K57.- codes, which is why it is important to understand the rules for each code, especially when coding cases of complicated diverticulitis that may involve perforation or abscess. Code subcategories K57.0- through K57.3- exclude diverticulitis of both the small and large intestine with or without perforation and abscess because this is covered under K57.4- and K57.5-.

Additionally, the K57.- codes for diverticular disease feature Excludes1 and Excludes2 notes. The Excludes1 note instructs you not to report Q43.8 (Other specified congenital malformations of intestine) for congenital diverticulum of the intestine and Q43.0 (Meckel’s diverticulum (displaced) (hypertrophic)) with a K57.- code. On the other hand, you may report K38.2 (Diverticulum of appendix) with K57.- if the provider diagnoses the patient as having both conditions simultaneously.

Know the Right Times to Use K57.8- and K57.9- Codes

You should only use the K57.8- and K57.9- codes if the information available about a patient’s diverticular disease is not specific enough to use one of the other K57.- codes.

For patients diagnosed with diverticulitis with perforation and abscess whose cases do not apply to any other K57.-code, use one of the K57.8- codes with the appropriate 5^th character. Use K57.80 (Diverticulitis of intestine, part unspecified, with perforation and abscess without bleeding) for patients who do not have bleeding, while K57.81 (Diverticulitis of intestine, part unspecified, with perforation and abscess with bleeding) is appropriate for patients with bleeding.

The K57.9- codes include options for both diverticulosis and diverticulitis without perforation and abscess; refer to the list of 5^th characters under K57.9- to find the best match to the patient’s diagnosis and symptoms.

Michelle Falci, BA, M Falci Communications LLC