Other arthritis (M13)

ICD-10 code folder M13 covers various forms of other arthritis not classified elsewhere, including both monoarthritis (affecting a single joint) and polyarthritis (affecting multiple joints). These codes help specify arthritis by joint location and type when conditions don’t fit more common arthritis categories.

The M13.0 code represents polyarthritis, unspecified, which includes terms like polyarthropathy and arthropathy of multiple joints. Monoarthritis codes, such as M13.1 and its site-specific subcodes (e.g., M13.111 for right shoulder, M13.161 for right knee), identify arthritis limited to one joint without further classification. The codes from M13.8 onward cover other specified arthritis by joint and side, including shoulder, elbow, wrist, hand, hip, knee, ankle, and foot, with synonyms like allergic arthritis, inflammation of joint, and degenerative polyarthritis indicating varied underlying causes and presentations. This detailed coding system assists coders and clinicians in capturing specific arthritis diagnoses when common categories do not apply, ensuring accurate classification for diverse joint disorders.

  • Diseases of the musculoskeletal system and connective tissue (M00–M99)

    • Inflammatory polyarthropathies (M05-M14)

        • Other arthritis (M13)

        • M13 Other arthritis
        • M13.0 Polyarthritis, unspecified
        • M13.1 Monoarthritis, not elsewhere classified
        • M13.10 Monoarthritis, not elsewhere classified, unspecified site
        • M13.11 Monoarthritis, not elsewhere classified, shoulder
        • M13.111 Monoarthritis, not elsewhere classified, right shoulder
        • M13.112 Monoarthritis, not elsewhere classified, left shoulder
        • M13.119 Monoarthritis, not elsewhere classified, unspecified shoulder
        • M13.12 Monoarthritis, not elsewhere classified, elbow
        • M13.121 Monoarthritis, not elsewhere classified, right elbow
        • M13.122 Monoarthritis, not elsewhere classified, left elbow
        • M13.129 Monoarthritis, not elsewhere classified, unspecified elbow
        • M13.13 Monoarthritis, not elsewhere classified, wrist
        • M13.131 Monoarthritis, not elsewhere classified, right wrist
        • M13.132 Monoarthritis, not elsewhere classified, left wrist
        • M13.139 Monoarthritis, not elsewhere classified, unspecified wrist
        • M13.14 Monoarthritis, not elsewhere classified, hand
        • M13.141 Monoarthritis, not elsewhere classified, right hand
        • M13.142 Monoarthritis, not elsewhere classified, left hand
        • M13.149 Monoarthritis, not elsewhere classified, unspecified hand
        • M13.15 Monoarthritis, not elsewhere classified, hip
        • M13.151 Monoarthritis, not elsewhere classified, right hip
        • M13.152 Monoarthritis, not elsewhere classified, left hip
        • M13.159 Monoarthritis, not elsewhere classified, unspecified hip
        • M13.16 Monoarthritis, not elsewhere classified, knee
        • M13.161 Monoarthritis, not elsewhere classified, right knee
        • M13.162 Monoarthritis, not elsewhere classified, left knee
        • M13.169 Monoarthritis, not elsewhere classified, unspecified knee
        • M13.17 Monoarthritis, not elsewhere classified, ankle and foot
        • M13.171 Monoarthritis, not elsewhere classified, right ankle and foot
        • M13.172 Monoarthritis, not elsewhere classified, left ankle and foot
        • M13.179 Monoarthritis, not elsewhere classified, unspecified ankle and foot
        • M13.8 Other specified arthritis
        • M13.80 Other specified arthritis, unspecified site
        • M13.81 Other specified arthritis, shoulder
        • M13.811 Other specified arthritis, right shoulder
        • M13.812 Other specified arthritis, left shoulder
        • M13.819 Other specified arthritis, unspecified shoulder
        • M13.82 Other specified arthritis, elbow
        • M13.821 Other specified arthritis, right elbow
        • M13.822 Other specified arthritis, left elbow
        • M13.829 Other specified arthritis, unspecified elbow
        • M13.83 Other specified arthritis, wrist
        • M13.831 Other specified arthritis, right wrist
        • M13.832 Other specified arthritis, left wrist
        • M13.839 Other specified arthritis, unspecified wrist
        • M13.84 Other specified arthritis, hand
        • M13.841 Other specified arthritis, right hand
        • M13.842 Other specified arthritis, left hand
        • M13.849 Other specified arthritis, unspecified hand
        • M13.85 Other specified arthritis, hip
        • M13.851 Other specified arthritis, right hip
        • M13.852 Other specified arthritis, left hip
        • M13.859 Other specified arthritis, unspecified hip
        • M13.86 Other specified arthritis, knee
        • M13.861 Other specified arthritis, right knee
        • M13.862 Other specified arthritis, left knee
        • M13.869 Other specified arthritis, unspecified knee
        • M13.87 Other specified arthritis, ankle and foot
        • M13.871 Other specified arthritis, right ankle and foot
        • M13.872 Other specified arthritis, left ankle and foot
        • M13.879 Other specified arthritis, unspecified ankle and foot
        • M13.88 Other specified arthritis, other site
        • M13.89 Other specified arthritis, multiple sites

Instructional Notations

Type 1 Excludes

A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.

Clinical Terms

The following clinical terms provide additional context, helping users better understand the clinical background and common associations for each diagnosis listed in this section. Including related terms alongside ICD-10-CM codes supports coders, billers, and healthcare professionals in improving accuracy, enhancing documentation, and facilitating research or patient education.

Arthritis

Acute or chronic inflammation of JOINTS.

Arthritis, Experimental

ARTHRITIS that is induced in experimental animals. Immunological methods and infectious agents can be used to develop experimental arthritis models. These methods include injections of stimulators of the immune response, such as an adjuvant (ADJUVANTS, IMMUNOLOGIC) or COLLAGEN.

Arthritis, Gouty

Arthritis, especially of the great toe, as a result of gout. Acute gouty arthritis often is precipitated by trauma, infection, surgery, etc. The initial attacks are usually monoarticular but later attacks are often polyarticular. Acute and chronic gouty arthritis are associated with accumulation of MONOSODIUM URATE in and around affected joints.

Arthritis, Infectious

Arthritis caused by BACTERIA; RICKETTSIA; MYCOPLASMA; VIRUSES; FUNGI; or PARASITES.

Arthritis, Juvenile

Arthritis in children, with onset before 16 years of age. The terms juvenile rheumatoid arthritis (JRA) and juvenile idiopathic arthritis (JIA) refer to classification systems for chronic arthritis in children. Only one subtype of juvenile arthritis (polyarticular-onset, rheumatoid factor-positive) clinically resembles adult rheumatoid arthritis and is considered its childhood equivalent.

Arthritis, Psoriatic

A type of inflammatory arthritis associated with PSORIASIS, often involving the axial joints and the peripheral terminal interphalangeal joints. It is characterized by the presence of HLA-B27-associated SPONDYLARTHROPATHY, and the absence of rheumatoid factor.

Arthritis, Reactive

An aseptic, inflammatory arthritis developing secondary to a primary extra-articular infection, most typically of the GASTROINTESTINAL TRACT or UROGENITAL SYSTEM. The initiating trigger pathogens are usually SHIGELLA; SALMONELLA; YERSINIA; CAMPYLOBACTER; or CHLAMYDIA TRACHOMATIS. Reactive arthritis is strongly associated with HLA-B27 ANTIGEN.

Arthritis, Rheumatoid

A chronic systemic disease, primarily of the joints, marked by inflammatory changes in the synovial membranes and articular structures, widespread fibrinoid degeneration of the collagen fibers in mesenchymal tissues, and by atrophy and rarefaction of bony structures. Etiology is unknown, but autoimmune mechanisms have been implicated.

Arthritis-Encephalitis Virus, Caprine

A species of LENTIVIRUS, subgenus ovine-caprine lentiviruses (LENTIVIRUSES, OVINE-CAPRINE), closely related to VISNA-MAEDI VIRUS and causing acute encephalomyelitis; chronic arthritis; PNEUMONIA; MASTITIS; and GLOMERULONEPHRITIS in goats. It is transmitted mainly in the colostrum and milk.

Crystal Arthropathies

Joint disorders that are characterized by accumulation of microcrystals in and around the joint including in the SYNOVIAL FLUID. They are classified according to the chemical nature of the crystals such as CALCIUM PYROPHOSPHATE; basic CALCIUM PHOSPHATES; and monosodium urate (see URIC ACID).

Joints

Also known as articulations, these are points of connection between the ends of certain separate bones, or where the borders of other bones are juxtaposed.

Lyme Disease

An infectious disease caused by a spirochete, BORRELIA BURGDORFERI, which is transmitted chiefly by Ixodes dammini (see IXODES) and pacificus ticks in the United States and Ixodes ricinis (see IXODES) in Europe. It is a disease with early and late cutaneous manifestations plus involvement of the nervous system, heart, eye, and joints in variable combinations. The disease was formerly known as Lyme arthritis and first discovered at Old Lyme, Connecticut.

Osteoarthritis

A progressive, degenerative joint disease, the most common form of arthritis, especially in older persons. The disease is thought to result not from the aging process but from biochemical changes and biomechanical stresses affecting articular cartilage. In the foreign literature it is often called osteoarthrosis deformans.

Rheumatic Fever

A febrile disease occurring as a delayed sequela of infections with STREPTOCOCCUS PYOGENES. It is characterized by multiple focal inflammatory lesions of the connective tissue structures, such as the heart, blood vessels, and joints (POLYARTHRITIS) and brain, and by the presence of ASCHOFF BODIES in the myocardium and skin.

Spine

The spinal or vertebral column.

Spondylarthritis

Inflammation of the joints of the SPINE, the intervertebral articulations.