In many cases, patients who present to the emergency department with symptoms of nausea, vomiting, diarrhea and abdominal pain are diagnosed with gastroenteritis after their visit to the emergency department. Gastroenteritis is one of the top 25 diagnosis codes worked up in the emergency department and coded by web2pro Emergency Department coders. 

Gastroenteritis is defined as “inflammation of the lining of the stomach and intestines, predominantly manifested by upper gastrointestinal (GI) tract symptoms (anorexia, nausea, vomiting), diarrhea, and abdominal discomfort.”1 Many differential conditions are taken into consideration after the physician obtains the patient’s past medical history (i.e. if the patient was on any medications, like antibiotics) and history of recent contact with any food, water, or people who might be infected with certain microorganisms. The physician would also conduct a thorough physical examination before considering any management options of diagnostic study or therapeutic intervention.

Gastroenteritis may be of non-specific, uncertain, unknown etiology or of viral, bacteria, or parasitic etiology. Moreover, gastroenteritis can present as either non-infectious or infectious. The type and severity of the condition’s symptoms would depend on what may have caused the symptoms, the length of the occurrence, the patient’s tolerance level and how much of the patient’s organ system is contaminated/affected.  The severity of the condition will directly affect  the gastrointestinal system and then associated organ systems, all requiring the need for additional medical attention. As an example, if a patient complains of nausea, vomiting and persistent diarrhea, that patient will become, to some degree, dehydrated and may require fluid/electrolyte replacement therapy.

Treatment generally includes bed rest with easy access to the bathroom being desirable, fluids as can be tolerated, but even while still vomiting, sips of fluids are recommended. If the condition shows severe dehydration, IV replacement of electrolytes may be necessary, and even antiemetic (a drug that is effective against vomiting and nausea) medication may be warranted.

There is a one-to-one crosswalk (ICD-9 to ICD-10) for Gastroenteritis, not otherwise specified (NOS) but both ICD-9 and ICD-10 contain many other types of gastroenteritis including, but not limited to, what is shown on the table below.

ICD-9 to ICD-10 Documentation for Gastroenteritis

As mentioned above, treatment for gastroenteritis depends on the patient’s presentation, age and any current or historical underlying conditions.

It is imperative that the provider document exactly what the examination and the diagnostic studies’ findings are, if any, to determine the exact course of action for the condition presented or defined after study. This will also allow the coding staff to select the most appropriate ICD-9 or ICD-10 diagnosis code for reporting on the claim for reimbursement.

1The Merck Manual, Seventeenth Edition, Centennial Edition, Section 3, Chapter 28 Gastroenteritis, Page 283


  • ICD-10-CM, 2014 Complete Draft Code Set, Chapter 11, Page 621, Symptoms, Signs, and Abnormal Clinical and Laboratory Findings, not Elsewhere Classified (K00 – K95), AAPC, Optuminsight 2013
  • ICD-9-CM, 2014, Sixth Edition, 9th Revision, Clinical Modification, Chapter 9, Page 171, Diseases of the Digestive System (codes 520 - 579), Editor – Anita C. Hart, Optuminsight August 2013
  • Merck Manual, Section 3, Pages  283 – 293, Editor – Keryn A. G. Lane, Publisher – Gary Zelko, June 1999


Author - Male

About the author

Robert Bunting, CPC, CPC-H, CHC, CEDC, CEMC, CAC is Compliance Director – Emergency Medicine, web2pro Business Performance Services.