2023 ICD-10-CM Diagnosis Code K31.1

Adult hypertrophic pyloric stenosis

    2016 2017 2018 2019 2020 2021 2022 2023 Billable/Specific Code Adult Dx (15-124 years)
  • K31.1 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.
  • The 2023 edition of ICD-10-CM K31.1 became effective on October 1, 2022.
  • This is the American ICD-10-CM version of K31.1 - other international versions of ICD-10 K31.1 may differ.
ICD-10-CM Coding Rules
  • K31.1 is applicable to adult patients aged 15 - 124 years inclusive.
Applicable To
  • Pyloric stenosis NOS
Type 1 Excludes
Type 1 Excludes Help
A type 1 excludes note is a pure excludes. It means "not coded here". A type 1 excludes note indicates that the code excluded should never be used at the same time as K31.1. A type 1 excludes note is for used for when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
  • congenital or infantile pyloric stenosis (
    ICD-10-CM Diagnosis Code Q40.0

    Congenital hypertrophic pyloric stenosis

      2016 2017 2018 2019 2020 2021 2022 2023 Billable/Specific Code POA Exempt
    Applicable To
    • Congenital or infantile constriction
    • Congenital or infantile hypertrophy
    • Congenital or infantile spasm
    • Congenital or infantile stenosis
    • Congenital or infantile stricture
The following code(s) above K31.1 contain annotation back-references
Annotation Back-References
In this context, annotation back-references refer to codes that contain:
  • Applicable To annotations, or
  • Code Also annotations, or
  • Code First annotations, or
  • Excludes1 annotations, or
  • Excludes2 annotations, or
  • Includes annotations, or
  • Note annotations, or
  • Use Additional annotations
that may be applicable to K31.1:
  • K00-K95
    2023 ICD-10-CM Range K00-K95

    Diseases of the digestive system

    Type 2 Excludes
    • certain conditions originating in the perinatal period (P04-P96)
    • certain infectious and parasitic diseases (A00-B99)
    • complications of pregnancy, childbirth and the puerperium (O00-O9A)
    • congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
    • endocrine, nutritional and metabolic diseases (E00-E88)
    • injury, poisoning and certain other consequences of external causes (S00-T88)
    • neoplasms (C00-D49)
    • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
    Diseases of the digestive system
  • K20-K31
    2023 ICD-10-CM Range K20-K31

    Diseases of esophagus, stomach and duodenum

    Type 2 Excludes
    Diseases of esophagus, stomach and duodenum
  • K31
    ICD-10-CM Diagnosis Code K31

    Other diseases of stomach and duodenum

      2016 2017 2018 2019 2020 2021 2022 2023 Non-Billable/Non-Specific Code
    • functional disorders of stomach
    Type 2 Excludes
    Other diseases of stomach and duodenum
Approximate Synonyms
  • Acquired hypertrophic pyloric stenosis
  • Gastric outlet obstruction
  • Obstruction, gastric outlet
  • Pyloric obstruction
  • Pyloric stenosis
  • Stenosis, pyloric
Clinical Information
  • Narrowing of the pyloric canal with varied etiology. A common form is due to muscle hypertrophy (pyloric stenosis, hypertrophic) seen in infants.
  • Narrowing of the pyloric lumen caused either by hypertrophy of the surrounding muscles or tissue scarring due to a chronic peptic ulcer.
ICD-10-CM K31.1 is grouped within Diagnostic Related Group(s) (MS-DRG v40.0):
  • 380 Complicated peptic ulcer with mcc
  • 381 Complicated peptic ulcer with cc
  • 382 Complicated peptic ulcer without cc/mcc

Convert K31.1 to ICD-9-CM

Code History
  • 2016 (effective 10/1/2015): New code (first year of non-draft ICD-10-CM)
  • 2017 (effective 10/1/2016): No change
  • 2018 (effective 10/1/2017): No change
  • 2019 (effective 10/1/2018): No change
  • 2020 (effective 10/1/2019): No change
  • 2021 (effective 10/1/2020): No change
  • 2022 (effective 10/1/2021): No change
  • 2023 (effective 10/1/2022): No change

Diagnosis Index entries containing back-references to K31.1:

ICD-10-CM Codes Adjacent To K31.1
K29.71 …… with bleeding
K29.8 Duodenitis
K29.80 …… without bleeding
K29.81 …… with bleeding
K29.9 Gastroduodenitis, unspecified
K29.90 …… without bleeding
K29.91 …… with bleeding
K30 Functional dyspepsia
K31 Other diseases of stomach and duodenum
K31.0 Acute dilatation of stomach
K31.1 Adult hypertrophic pyloric stenosis
K31.2 Hourglass stricture and stenosis of stomach
K31.3 Pylorospasm, not elsewhere classified
K31.4 Gastric diverticulum
K31.5 Obstruction of duodenum
K31.6 Fistula of stomach and duodenum
K31.7 Polyp of stomach and duodenum
K31.8 Other specified diseases of stomach and duodenum
K31.81 Angiodysplasia of stomach and duodenum
K31.811 …… with bleeding
K31.819 …… without bleeding

Reimbursement claims with a date of service on or after October 1, 2015 require the use of ICD-10-CM codes.