2022 ICD-10-CM Code K51.312

Ulcerative (chronic) rectosigmoiditis with intestinal obstruction

Version 2021

Valid for Submission

ICD-10:K51.312
Short Description:Ulcerative (chronic) rectosigmoiditis w intestinal obst
Long Description:Ulcerative (chronic) rectosigmoiditis with intestinal obstruction

Code Classification

  • Diseases of the digestive system (K00–K93)
    • Noninfective enteritis and colitis (K50-K52)
      • Ulcerative colitis (K51)

K51.312 is a billable diagnosis code used to specify a medical diagnosis of ulcerative (chronic) rectosigmoiditis with intestinal obstruction. The code K51.312 is valid during the fiscal year 2022 from October 01, 2021 through September 30, 2022 for the submission of HIPAA-covered transactions.

The ICD-10-CM code K51.312 might also be used to specify conditions or terms like intestinal obstruction due to chronic ulcerative proctitis, intestinal obstruction due to chronic ulcerative rectosigmoiditis or intestinal obstruction due to ulcerative colitis.

Index to Diseases and Injuries

The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10 code(s). The following references for the code K51.312 are found in the index:

Approximate Synonyms

The following clinical terms are approximate synonyms or lay terms that might be used to identify the correct diagnosis code:

Convert K51.312 to ICD-9 Code

Information for Patients


Intestinal Obstruction

An intestinal obstruction occurs when food or stool cannot move through the intestines. The obstruction can be complete or partial. There are many causes. The most common are adhesions, hernias, cancers, and certain medicines.

Symptoms include

A complete intestinal obstruction is a medical emergency. It often requires surgery.

NIH: National Institute of Diabetes and Digestive and Kidney Diseases


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Ulcerative Colitis

Ulcerative colitis (UC) is a disease that causes inflammation and sores, called ulcers, in the lining of the rectum and colon. It is one of a group of diseases called inflammatory bowel disease.

UC can happen at any age, but it usually starts between the ages of 15 and 30. It tends to run in families. The most common symptoms are pain in the abdomen and blood or pus in diarrhea. Other symptoms may include

About half of people with UC have mild symptoms.

Doctors use blood tests, stool tests, colonoscopy or sigmoidoscopy, and imaging tests to diagnose UC. Several types of drugs can help control it. Some people have long periods of remission, when they are free of symptoms. In severe cases, doctors must remove the colon.

NIH: National Institute of Diabetes and Digestive and Kidney Diseases


[Learn More in MedlinePlus]

Ulcerative colitis

Ulcerative colitis is a chronic disorder that affects the digestive system. This condition is characterized by abnormal inflammation of the inner surface of the rectum and colon, which make up most of the length of the large intestine. The inflammation usually causes open sores (ulcers) to develop in the large intestine. Ulcerative colitis usually appears between ages 15 and 30, although it can develop at any age. The inflammation tends to flare up multiple times throughout life, which causes recurring signs and symptoms.

The most common symptoms of ulcerative colitis are abdominal pain and cramping and frequent diarrhea, often with blood, pus, or mucus in the stool. Other signs and symptoms include nausea, loss of appetite, fatigue, and fevers. Chronic bleeding from the inflamed and ulcerated intestinal tissue can cause a shortage of red blood cells (anemia) in some affected individuals. People with this disorder have difficulty absorbing enough fluids and nutrients from their diet and often experience weight loss. Affected children usually grow more slowly than normal. Less commonly, ulcerative colitis causes problems with the skin, joints, eyes, kidneys, or liver, which are most likely due to abnormal inflammation.

Toxic megacolon is a rare complication of ulcerative colitis that can be life-threatening. Toxic megacolon involves widening of the colon and an overwhelming bacterial infection (sepsis). Ulcerative colitis also increases the risk of developing colon cancer, especially in people whose entire colon is inflamed and in people who have had ulcerative colitis for 8 or more years.

Ulcerative colitis is one common form of inflammatory bowel disease (IBD). Another type of IBD, Crohn disease, also causes chronic inflammation of the intestines. Unlike ulcerative colitis, which affects only the inner surface of the large intestine, Crohn disease can cause inflammation in any part of the digestive system, and the inflammation extends deeper into the intestinal tissue.


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Code History

  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016 (First year ICD-10-CM implemented into the HIPAA code set)