ICD10
ICD-10 Code K59.3: Megacolon, not elsewhere classified
Reviewed by HealthAssure Clinical TeamUpdated 26 May 2026
What is this code?
ICD-10 entries help standardize how diagnoses are organized for coding, reporting, analytics, and documentation. This code sits within the broader ICD-10 area for Diseases of the digestive system (K00-K95).
When is it used?
- May be used when a clinician documents megacolon, not elsewhere classified in a patient's medical record.
- May appear in hospital records, claims, referrals, and clinical documentation.
- This code may act more like a grouping or parent code, so a more specific child code may be used in final documentation when available.
What it does not mean
- A code alone does not explain severity, treatment plan, or outcome.
- A medical code should not be treated as a substitute for a doctor's diagnosis or advice.
- This entry may represent a broader category rather than the most specific billable code.
Code hierarchy
chapter
11Diseases of the digestive system (K00-K95)
block
K55-K64Other diseases of intestines
category
K59Other functional intestinal disorders
currentK59
Official coding notes
Inclusion terms
- Dilatation of colon
Applicable to
- , if applicable (T51-T65) to identify toxic agent
Excludes1 (do not code together)
- congenital megacolon (aganglionic) (Q43.1)
- megacolon (due to) (in) Chagas' disease (B57.32)
- megacolon (due to) (in) Clostridium difficile (A04.7-)
- megacolon (due to) (in) Hirschsprung's disease (Q43.1)
Code first
- , if applicable (T51-T65) to identify toxic agent
Where you may see this code
You may see this entry in coding references, medical records, or claims workflows when a broader diagnosis category is being reviewed before a more specific code is chosen.
Related specialists
GastroenterologistGeneral Physician
Related codes
Sibling codes
Mapped diagnoses and classifications
SNOMED_CT 33995003high
Acquired megacolon
Source: SNOMED International ICD-10 map
SNOMED_CT 1269300004high
Acquired megacolon in adult
Source: SNOMED International ICD-10 map
SNOMED_CT 259058004high
Acquired megacolon in child
Source: SNOMED International ICD-10 map
SNOMED_CT 46996005high
Dilatation of cecum
Source: SNOMED International ICD-10 map
SNOMED_CT 46791000087103high
Dilatation of large intestine
Source: SNOMED International ICD-10 map
SNOMED_CT 235830005high
Drug-induced megacolon
Source: SNOMED International ICD-10 map
Coding guidelines
Compatibility
Legacy code aligns to an official FY 2026 category. Frontend should resolve to the official category page and surface the billable child codes.
Legacy codes
K59.3
Replacement codes
K59.31 — Toxic megacolonK59.39 — Other megacolon
Common synonyms
Megacolon, not elsewhere classified
Frequently asked questions
About this content
This page is prepared by HealthAssure's clinical team using official coding standards from ICD-10. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.