Coding Bowel Obstruction in ICD-10-CM

With the implementation of ICD-10-CM came different codes and coding rules for many diagnoses. One of these is the coding of bowel obstruction when the patient presents for this condition that is caused by another condition.  In the past, bowel obstruction was almost always coded as a diagnosis as the physician usually addressed the condition and did work up as to the cause, many times addressing the cause also. 

In 2017 there was a Coding Clinic that stated that coders would follow the Excludes1 note and NOT code bowel obstruction when documented as due to an underlying cause. However for FY2024, as of October 1, 2023, that excludes1 note has been removed and the 2017 Coding Clinic advice is no longer valid. The coder may now code bowel obstruction when documented. Keep in mind that there are some combination codes such as adhesions with bowel obstruction which is one code according to the index.

What is bowel obstruction caused by?

Bowel obstruction usually occurs when the lumen of the intestine is either obstructed by fecal matter or other debris/foreign bodies, or is compressed by external forces such as tumors or adhesions.  These are called a “mechanical” cause of the obstruction.   When there is a condition in which the bowel does not work correctly, but there is no structural problem causing it, it is called “ileus.”  We are going to talk about mechanical bowel obstruction in this coding tip.

Mechanical bowel obstruction can be caused by a number of conditions.  Some of the most common causes are:

• Adhesions or scar tissue that forms after surgery
• Foreign bodies (objects that are swallowed and block the intestines)
• Gallstones (rare)
• Hernias
• Impacted stool
• Intussusception (telescoping of one segment of bowel into another)
• Tumors blocking the intestines
• Volvulus (twisted intestine)

Symptoms may include:

• Abdominal swelling (distention)
• Abdominal fullness, gas
• Abdominal pain and cramping
• Breath odor
• Constipation
• Diarrhea
• Inability to pass gas
• Vomiting

Exams and Tests

During a physical exam, the health care provider may find bloating, tenderness, or hernias in the abdomen.

Tests that show obstruction include:

• Abdominal CT scan
• Abdominal x-ray
• Barium enema
• Upper GI and small bowel series

Treatment

Treatment involves placing a tube through the nose into the stomach or intestine. This is to help relieve abdominal swelling (distention) and vomiting. Volvulus of the large bowel may be treated by passing a tube into the rectum.

Surgery may be needed to relieve the obstruction if the tube does not relieve the symptoms. It may also be needed if there are signs of tissue death.

How is bowel obstruction coded in ICD-10-CM?

Bowel obstruction can be due to many different causes as was stated above.  The ICD-10-CM index can be a little tricky when coding intestinal obstruction. Some encoders actually put in a warning entry such as the entries in red below that reflect tabular excludes1 notes and Coding Clinic advice.  See the index entry below:

ICD-10-CM Index entry for obstruction, intestine: 

Obstruction:

intestine K56.609

complete K56.601

incomplete K56.600

partial K56.600

with

      adhesions (intestinal) (peritoneal) K56.50

           complete K56.52

           incomplete K56.51

           partial K56.51

adynamic K56.0

by gallstone K56.3

congenital (small) Q41.9

      large Q42.9

            specified part NEC Q42.8

neurogenic K56.0

      Hirschsprung’s disease or megacolon Q43.1

newborn P76.9

      due to

           fecaliths P76.8

           inspissated milk P76.2

           meconium (plug) P76.0

                 in mucoviscidosis E84.11

      specified NEC P76.8

postoperative K91.30

      complete K91.32

      incomplete K91.31

      partial K91.31

reflex K56.0

specified NEC K56.699

      complete K56.691

      incomplete K56.690

      partial K56.690

volvulus K56.2

Code assignment starts with the index along with  medical record documentation as to the cause of the intestinal obstruction.  There are also entries for “partial” or “complete” intestinal obstruction, so the coder will need to look for that documentation. Note that it does not make any difference if it is the small or large intestine that is obstructed in code assignment.

If the physician documents a large intestine obstruction for example, and does not find a specific cause, then the unspecified code, K56.609, Unspecified intestinal obstruction, unspecified as to partial versus complete obstruction  is assigned. 

As of October 1, 2023, coders can code both the underlying condition AND the bowel obstruction code. The principal diagnosis would depend on the circumstances of the admission.

Here is the tabular for specified condition causing intestinal obstruction that coders must follow:

K56.69  Other intestinal obstruction

Enterostenosis NOS

Obstructive ileus NOS

Occlusion of colon or intestine NOS

Stenosis of colon or intestine NOS

Stricture of colon or intestine NOS

K56.690  Other partial intestinal

K56.691   Other complete intestinal obstruction

K56.699   Other intestinal obstruction unspecified as to partial versus complete obstruction

Other intestinal obstruction, NEC

In addition, coders may see Excludes1 note at K56 that excludes intestinal obstruction with these conditions.

K56    Paralytic ileus and intestinal obstruction without hernia

      Excludes1: congenital stricture or stenosis of intestine (Q41-Q42)

                        cystic fibrosis with meconium ileus (E84.11)

                       ischemic stricture of intestine (K55.1)

                       meconium ileus NOS (P76.0)

                       neonatal intestinal obstructions classifiable to P76.-

                       obstruction of duodenum (K31.5)

                       postprocedural intestinal obstruction (K91.3-)

Excludes2: stenosis of anus or rectum (K62.4)

In addition, certain conditions will include a “with” notation and code within the index.   See Adhesions entry below from the index:

Adhesions, adhesive (postinfective) K66.0

       with intestinal obstruction K56.50

complete K56.52

incomplete K56.51

partial K56.51

So given the above, if a patient has intestinal obstruction due to adhesions, only code K56.50, intestinal adhesions [bands], unspecified as to partial versus complete obstruction would be assigned, not two codes.

Lastly, if intestinal obstruction is a complication of surgery, code K91.3-, may be warranted. Coders must validate that this is truly intestinal obstruction as a complication of surgery, and not just occurring after surgery due to another cause. The term “postoperative’ can be misleading.  A query may be necessary.

Take Aways

• Coders must be aware of the index entries for intestinal obstruction and follow the index
• For conditions in the index, look for “with obstruction” underneath the main entry or subterm entries
• Always follow the Excludes1 notes at these codes in the tabular, and at time these are located at the three digit section code or chapter beginning rather than only individual codes
• Check the documentation for “partial” or “complete” obstruction and for the documented cause of intestine obstruction
• Check the documentation for “postoperative” bowel obstruction and documentation that it is a complication of surgery.  If in doubt query the physician.

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The information contained in this post is valid at the time of posting. Viewers are encouraged to research subsequent official guidance in the areas associated with the topic as they can change rapidly.