ICD-10-CM Codes
M00-M99 Diseases of the musculoskeletal system and connective tissue
M30-M36 Systemic connective tissue disorders
M35- Other systemic involvement of connective tissue
2023 ICD-10-CM Diagnosis Code M35.81

2023 ICD-10-CM Diagnosis Code M35.81

Multisystem inflammatory syndrome

2016

2017

2018

2019

2020

2021

2022

2023

Billable/Specific Code

M35.81 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 M35.81 became effective on October 1, 2022.
This is the American ICD-10-CM version of M35.81 - other international versions of ICD-10 M35.81 may differ.

Applicable To

MIS-A
MIS-C
Multisystem inflammatory syndrome in adults
Multisystem inflammatory syndrome in children
Pediatric inflammatory multisystem syndrome
PIMS

Use Additional

Use Additional Help

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. In most cases the manifestation codes will have in the code title, "in diseases classified elsewhere." Codes with this title are a component of the etiology/manifestation convention. The code title indicates that it is a manifestation code. "In diseases classified elsewhere" codes are never permitted to be used as first listed or principle diagnosis codes. They must be used in conjunction with an underlying condition code and they must be listed following the underlying condition.

code, if applicable, for:
exposure to COVID-19 or SARS-CoV-2 infection (
ICD-10-CM Diagnosis Code Z20.822
Contact with and (suspected) exposure to COVID-19
Applicable To
- Contact with and (suspected) exposure to SARS-CoV-2
Z20.822
)
personal history of COVID-19 (
ICD-10-CM Diagnosis Code Z86.16
Personal history of COVID-19
Type 1 Excludes
- post COVID-19 condition (U09.9)
Z86.16
)
post COVID-19 condition (
ICD-10-CM Diagnosis Code U09.9
Post COVID-19 condition, unspecified
Code First
- the specific condition related to COVID-19 if known, such as:
- chronic respiratory failure (J96.1-)
- loss of smell (R43.8)
- loss of taste (R43.8)
- multisystem inflammatory syndrome (M35.81)
- pulmonary embolism (I26.-)
- pulmonary fibrosis (J84.10)
Note
- This code enables establishment of a link with COVID-19.
- This code is not to be used in cases that are still presenting with active COVID-19. However, an exception is made in cases of re-infection with COVID-19, occurring with a condition related to prior COVID-19.
- Post-acute sequela of COVID-19
U09.9
)

Code First

Code First Help

Certain conditions have both an underlying etiology and multiple body system manifestations due to the underlying etiology. For such conditions, 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. In most cases the manifestation codes will have in the code title, "in diseases classified elsewhere." Codes with this title are a component of the etiology/manifestation convention. The code title indicates that it is a manifestation code. "In diseases classified elsewhere" codes are never permitted to be used as first listed or principle diagnosis codes. They must be used in conjunction with an underlying condition code and they must be listed following the underlying condition.

, if applicable, COVID-19 (
ICD-10-CM Diagnosis Code U07.1
COVID-19
Type 1 Excludes
- coronavirus infection, unspecified (B34.2)
- coronavirus as the cause of diseases classified elsewhere (B97.2-)
- pneumonia due to SARS-associated coronavirus (J12.81)
Use Additional
- code to identify pneumonia or other manifestations
U07.1
)

Code Also

Code Also Help

A code also note instructs that 2 codes may be required to fully describe a condition but the sequencing of the two codes is discretionary, depending on the severity of the conditions and the reason for the encounter.

any associated complications such as:
acute hepatic failure (
ICD-10-CM Diagnosis Code K72.0
Acute and subacute hepatic failure
Applicable To
- Acute non-viral hepatitis NOS
K72.0-
)
acute kidney failure (
ICD-10-CM Diagnosis Code N17
- N17 Acute kidney failure
  - N17.0 Acute kidney failure with tubular necrosis
  - N17.1 Acute kidney failure with acute cortical necr...
  - N17.2 Acute kidney failure with medullary necrosis
  - N17.8 Other acute kidney failure
  - N17.9 Acute kidney failure, unspecified
N17.-
)
acute myocarditis (
ICD-10-CM Diagnosis Code I40
- I40 Acute myocarditis
  - I40.0 Infective myocarditis
  - I40.1 Isolated myocarditis
  - I40.8 Other acute myocarditis
  - I40.9 Acute myocarditis, unspecified
I40.-
)
acute respiratory distress syndrome (
ICD-10-CM Diagnosis Code J80
Acute respiratory distress syndrome
Applicable To
- Acute respiratory distress syndrome in adult or child
- Adult hyaline membrane disease
Type 1 Excludes
- respiratory distress syndrome in newborn (perinatal) (P22.0)
J80
)
cardiac arrhythmia (
ICD-10-CM Diagnosis Code I47
Paroxysmal tachycardia
Code First
- tachycardia complicating:
- abortion or ectopic or molar pregnancy (O00-O07, O08.8)
- obstetric surgery and procedures (O75.4)
Type 1 Excludes
- tachycardia NOS (R00.0)
- sinoauricular tachycardia NOS (R00.0)
- sinus [sinusal] tachycardia NOS (R00.0)
I47
-
ICD-10-CM Diagnosis Code I49
Other cardiac arrhythmias
Code First
- cardiac arrhythmia complicating:
- abortion or ectopic or molar pregnancy (O00-O07, O08.8)
- obstetric surgery and procedures (O75.4)
Type 1 Excludes
- neonatal dysrhythmia (P29.1-)
- sinoatrial bradycardia (R00.1)
- sinus bradycardia (R00.1)
- vagal bradycardia (R00.1)
Type 2 Excludes
- bradycardia NOS (R00.1)
I49
.-)
pneumonia due to COVID-19 (
ICD-10-CM Diagnosis Code J12.82
Pneumonia due to coronavirus disease 2019
Applicable To
- Pneumonia due to 2019 novel coronavirus (SARS-CoV-2)
- Pneumonia due to COVID-19
Code First
- COVID-19 (U07.1)
J12.82
)
severe sepsis (
ICD-10-CM Diagnosis Code R65.2
Severe sepsis
Applicable To
- Infection with associated acute organ dysfunction
- Sepsis with acute organ dysfunction
- Sepsis with multiple organ dysfunction
- Systemic inflammatory response syndrome due to infectious process with acute organ dysfunction
Code First
- underlying infection, such as:
- infection following a procedure (T81.4-)
- infections following infusion, transfusion and therapeutic injection (T80.2-)
- puerperal sepsis (O85)
- sepsis following complete or unspecified spontaneous abortion (O03.87)
- sepsis following ectopic and molar pregnancy (O08.82)
- sepsis following incomplete spontaneous abortion (O03.37)
- sepsis following (induced) termination of pregnancy (O04.87)
- sepsis NOS (A41.9)
Use Additional
- code to identify specific acute organ dysfunction, such as:
- acute kidney failure (N17.-)
- acute respiratory failure (J96.0-)
- critical illness myopathy (G72.81)
- critical illness polyneuropathy (G62.81)
- disseminated intravascular coagulopathy [DIC] (D65)
- encephalopathy (metabolic) (septic) (G93.41)
- hepatic failure (K72.0-)
R65.2-
)
viral cardiomyopathy (
ICD-10-CM Diagnosis Code B33.24
Viral cardiomyopathy
B33.24
)
viral pericarditis (
ICD-10-CM Diagnosis Code B33.23
Viral pericarditis
B33.23
)

The following code(s) above M35.81 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 M35.81:

M00-M99
2023 ICD-10-CM Range M00-M99
Diseases of the musculoskeletal system and connective tissue
Note
- Use an external cause code following the code for the musculoskeletal condition, if applicable, to identify the cause of the musculoskeletal condition
Type 2 Excludes
- arthropathic psoriasis (L40.5-)
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- compartment syndrome (traumatic) (T79.A-)
- 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 musculoskeletal system and connective tissue
M30-M36
2023 ICD-10-CM Range M30-M36
Systemic connective tissue disorders
Includes
- autoimmune disease NOS
- collagen (vascular) disease NOS
- systemic autoimmune disease
- systemic collagen (vascular) disease
Type 1 Excludes
- autoimmune disease, single organ or single cell-type -code to relevant condition category
Systemic connective tissue disorders
M35
ICD-10-CM Diagnosis Code M35
Other systemic involvement of connective tissue
Type 1 Excludes
- reactive perforating collagenosis (L87.1)
Other systemic involvement of connective tissue

ICD-10-CM M35.81 is grouped within Diagnostic Related Group(s) (MS-DRG v40.0):

545 Connective tissue disorders with mcc
546 Connective tissue disorders with cc
547 Connective tissue disorders without cc/mcc

Convert M35.81 to ICD-9-CM

Code History

2016 (effective 10/1/2015): No change
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

Code annotations containing back-references to M35.81:

Code First: U09.9

ICD-10-CM Diagnosis Code U09.9
Post COVID-19 condition, unspecified
Code First
- the specific condition related to COVID-19 if known, such as:
- chronic respiratory failure (J96.1-)
- loss of smell (R43.8)
- loss of taste (R43.8)
- multisystem inflammatory syndrome (M35.81)
- pulmonary embolism (I26.-)
- pulmonary fibrosis (J84.10)
Note
- This code enables establishment of a link with COVID-19.
- This code is not to be used in cases that are still presenting with active COVID-19. However, an exception is made in cases of re-infection with COVID-19, occurring with a condition related to prior COVID-19.
- Post-acute sequela of COVID-19

Diagnosis Index entries containing back-references to M35.81:

MIS-A M35.81
MIS-C M35.81
Multisystem inflammatory syndrome M35.81 (in adult) (in children)
Pediatric inflammatory multisystem syndrome M35.81
PIMS M35.81
Syndrome - see also Disease
- multisystem inflammatory M35.81 (in adults) (in children)
- pediatric inflammatory multisystem M35.81

ICD-10-CM Codes Adjacent To M35.81

M35.0C …… with dental involvement

M35.09 …… with other organ involvement

M35.1 Other overlap syndromes

M35.2 Behçet's disease

M35.3 Polymyalgia rheumatica

M35.4 Diffuse (eosinophilic) fasciitis

M35.5 Multifocal fibrosclerosis

M35.6 Relapsing panniculitis [Weber-Christian]

M35.7 Hypermobility syndrome

M35.8 Other specified systemic involvement of connective tissue

M35.81 Multisystem inflammatory syndrome

M35.89 Other specified systemic involvement of connective tissue

M35.9 Systemic involvement of connective tissue, unspecified

M36 Systemic disorders of connective tissue in diseases classified elsewhere

M36.0 Dermato(poly)myositis in neoplastic disease

M36.1 Arthropathy in neoplastic disease

M36.2 Hemophilic arthropathy

M36.3 Arthropathy in other blood disorders

M36.4 Arthropathy in hypersensitivity reactions classified elsewhere

M36.8 Systemic disorders of connective tissue in other diseases classified elsewhere

M40 Kyphosis and lordosis

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

2023 ICD-10-CM Diagnosis Code M35.81

Multisystem inflammatory syndrome

Contact with and (suspected) exposure to COVID-19

Personal history of COVID-19

Post COVID-19 condition, unspecified

COVID-19

Acute and subacute hepatic failure

Acute respiratory distress syndrome

Paroxysmal tachycardia

Other cardiac arrhythmias

Pneumonia due to coronavirus disease 2019

Severe sepsis

Viral cardiomyopathy

Viral pericarditis

Diseases of the musculoskeletal system and connective tissue

Systemic connective tissue disorders

Other systemic involvement of connective tissue

Post COVID-19 condition, unspecified