K58.9
Irritable bowel syndrome without diarrhea
Irritable bowel syndrome (IBS) without diarrhea is a common functional gastrointestinal disorder characterized by chronic abdominal pain, bloating, and altered bowel habits where diarrhea is not the predominant symptom. This classification typically encompasses patients who suffer from IBS with constipation (IBS-C) or mixed bowel habits (IBS-M), although specific codes exist for those subtypes. Diagnosis is primarily clinical, often utilizing the Rome IV criteria which focus on recurrent abdominal pain associated with defecation or changes in stool frequency and form. Unlike inflammatory bowel disease, IBS does not cause permanent damage to the intestines or increase the risk of colorectal cancer, but it significantly impacts quality of life.
Clinical Symptoms
- Recurrent abdominal pain
- Bloating and abdominal distension
- Constipation or infrequent bowel movements
- Straining during defecation
- Sense of incomplete evacuation
- Passing of mucus in the stool
- Hard or lumpy stools (Bristol Stool Scale 1 or 2)
Common Causes
- Gut-brain axis dysregulation
- Visceral hypersensitivity (increased sensitivity to pain in the gut)
- Altered gastrointestinal motility
- Changes in the gut microbiome (dysbiosis)
- Post-infectious changes following gastroenteritis
- Psychosocial factors including stress and anxiety
- Food sensitivities or intolerances
Documentation & Coding Tips
Specify the predominant bowel habit if known to determine if K58.1 (IBS with constipation) or K58.2 (Mixed IBS) is more appropriate than the non-specific K58.9.
Example: Patient meets Rome IV criteria for IBS with a predominance of hard stools; use K58.1 instead of K58.9.
Document the duration and frequency of symptoms to support the diagnosis of a chronic functional disorder.
Example: Abdominal pain present at least one day per week for the past three months with symptom onset at least six months prior to diagnosis.
Note the absence of 'red flag' symptoms such as unintended weight loss, rectal bleeding, or nocturnal symptoms to justify the functional diagnosis.
Example: Patient reports bloating and pain; negative for hematochezia, weight loss, or family history of IBD/CRC.