M35.81 - Multisystem inflammatory syndrome

Version 2023
ICD-10:M35.81
Short Description:Multisystem inflammatory syndrome
Long Description:Multisystem inflammatory syndrome
Status: Valid for Submission
Version:ICD-10-CM 2023
Code Classification:
  • Diseases of the musculoskeletal system and connective tissue (M00–M99)
    • Systemic connective tissue disorders (M30-M36)
      • Other systemic involvement of connective tissue (M35)

M35.81 is a billable ICD-10 code used to specify a medical diagnosis of multisystem inflammatory syndrome. The code is valid during the fiscal year 2023 from October 01, 2022 through September 30, 2023 for the submission of HIPAA-covered transactions.

Approximate Synonyms

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

Clinical Information

Tabular List of Diseases and Injuries

The Tabular List of Diseases and Injuries is a list of ICD-10 codes, organized "head to toe" into chapters and sections with coding notes and guidance for inclusions, exclusions, descriptions and more. The following references are applicable to this diagnosis code:


Inclusion Terms

Inclusion Terms
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.

Code First

Code First
Certain conditions have both an underlying etiology and multiple body system manifestations due to the underlying etiology. For such conditions, the ICD-10-CM has a coding convention that requires the underlying condition be sequenced first followed by the manifestation. Wherever such a combination exists, there is a "use additional code" note at the etiology code, and a "code first" note at the manifestation code. These instructional notes indicate the proper sequencing order of the codes, etiology followed by manifestation.

Code Also

Code Also
A "code also" note instructs that two codes may be required to fully describe a condition, but this note does not provide sequencing direction.

Use Additional Code

Use Additional Code
The “use additional code” indicates that a secondary code could be used to further specify the patient’s condition. This note is not mandatory and is only used if enough information is available to assign an additional code.

Index to Diseases and Injuries References

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 this diagnosis code are found in the injuries and diseases index:

Replacement Code

M3581 replaces the following previously assigned ICD-10 code(s):

Patient Education


Connective Tissue Disorders

Your connective tissue supports many different parts of your body, such as your skin, eyes, and heart. It is like a "cellular glue" that gives your body parts their shape and helps keep them strong. It also helps some of your tissues do their work. It is made of many kinds of proteins. Cartilage and fat are types of connective tissue.

Over 200 disorders that impact connective tissue. There are different types:

Each disorder has its own symptoms and needs different treatment.

NIH: National Institute of Arthritis and Musculoskeletal and Skin Diseases


[Learn More in MedlinePlus]

Code History