Non-Organ Specific Systemic Autoimmune Disorders

Coded Elsewhere:

Rheumatoid arthritis (FA20)

Lupus erythematosus

Definition of Lupus erythematosus: An autoimmune non-organ specific inflammatory disease characterised by the presence of antibodies to DNA, RNA and other components of the nucleus. It has a very variable clinical presentation and course ranging from an acute fulminant life-threatening disorder with involvement of heart, central nervous system and kidneys to an indolent chronic scarring skin disorder.

ICD 11 Code For Lupus erythematosus

4A40 Lupus erythematosus

Coded Elsewhere:

Subacute cutaneous lupus erythematosus (EB50)
Chronic cutaneous lupus erythematosus (EB51)
Neonatal lupus erythematosus (KA07.0)

4A40.0 Systemic lupus erythematosus

Definition of Systemic lupus erythematosus: Systemic lupus erythematosus (SLE) is a clinically multisystem disease, which is autoimmune in origin and is characterised by the presence of autoantibodies directed against nuclear antigens. Manifestations include rash, arthritis and fatigue, nephritis, neurological problems, anaemia and thrombocytopenia at the more severe end of the spectrum.

4A40.00 Systemic lupus erythematosus with skin involvement

Definition of Systemic lupus erythematosus with skin involvement: Systemic lupus erythematosus (SLE) involving the skin. This may present with a malar “butterfly” erythema or with extensive necrolysis of sun-exposed skin, particularly on the head, neck and upper torso.

Coded Elsewhere:

Immunobullous systemic lupus erythematosus (EB4Y)

4A40.0Y Other specified systemic lupus erythematosus

4A40.0Z Systemic lupus erythematosus unspecified

4A40.1 Drug-induced lupus erythematosus

Definition of Drug-induced lupus erythematosus: Drug-induced lupus erythematosus is a syndrome in which positive antinuclear antibodies are associated with symptoms, such as fever, malaise, arthritis, intense arthralgia/myalgia, serositis, and/or rash. The syndrome appears during therapy with certain medications (e.g., procainamide, hydralazine, phenytoin) and tumour necrosis factor inhibitors. It occurs predominantly in Caucasians, has less female predilection than SLE, rarely involves kidneys or brain, is rarely associated with anti-dsDNA, is commonly associated with antibodies to histones, and usually resolves over several weeks after discontinuation of the offending medication.

4A40.Y Other specified lupus erythematosus

4A40.Z Lupus erythematosus unspecified

Idiopathic inflammatory myopathy

Definition of Idiopathic inflammatory myopathy: These comprise a diverse group of syndromes that have in common persistent muscle inflammation of unknown pathophysiology, resulting in damage that affects muscle function. The inflammatory muscle disease can either be acute or chronic in nature.

ICD 11 Code For Idiopathic inflammatory myopathy

4A41 Idiopathic inflammatory myopathy

Coded Elsewhere:

Extraocular myositis (9C82.3)

4A41.0 Dermatomyositis

Definition of Dermatomyositis: Dermatomyositis is an inflammatory myopathy, showing progressive, symmetrical muscle weakness, low muscle endurance, and cutaneous manifestations such as Gottron’s papules, heliotrope rash, shawl sign, V-sign and mechanic’s hand. Internal organ manifestations such as interstitial pneumonia (pneumonitis) and myocarditis sometimes develop. The skin rash may precede the muscle symptoms and may be the only clinical sign of dermatomyositis in some patients (clinically, amyopathic dermatomyositis).

4A41.00 Adult dermatomyositis

Definition of Adult dermatomyositis: Adult dermatomyositis is a systemic inflammatory disorders affecting the skeletal muscles, the skin, and other organs. It is characterised by symmetric proximal muscle weakness, increased serum muscle enzymes, myopathic changes upon electromyography, typical histological findings on muscle biopsy, and typical dermatologic manifestations such as heliotrope rash or Gottron’s papules.

Exclusions:

Myasthenia gravis or certain specified neuromuscular junction disorders (BlockL2‑8C6)

4A41.01 Juvenile dermatomyositis

Definition of Juvenile dermatomyositis: Juvenile dermatomyositis is the early-onset form of dermatomyositis, a systemic autoimmune inflammatory muscle disorder, characterised by proximal muscle weakness, evocative skin lesion, and systemic manifestations.

4A41.0Z Dermatomyositis unspecified

4A41.1 Polymyositis

Definition of Polymyositis: Polymyositis is an inflammatory muscle disease of unknown aetiology occurring predominantly in adults and characterised clinically by proximal muscle weakness (shoulders, arms, thighs), often with associated myalgia. Involvement of pharyngeal and oesophageal muscles may result in dysphagia and a risk of aspiration pneumonia. Myocarditis with rhythm disturbances or cardiomyopathy is a rare but serious complication. Polymyositis may be associated with other autoimmune diseases, malignancy or viral infection. Although serum muscle enzyme concentrations and electromyography are usually abnormal, definitive diagnosis requires demonstration of characteristic histological changes, including muscle necrosis, muscle fibre regeneration and diffuse infiltration by CD8+ T lymphocytes, on muscle biopsy.

4A41.10 Juvenile polymyositis

Definition of Juvenile polymyositis: Juvenile polymyositis is a rare childhood idiopathic inflammatory myopathy. It is frequently misdiagnosed, as it lacks a unique clinical phenotype. Traditionally, it presents with weakness of the proximal muscles that evolves over weeks to months. The primary histologic features in are fibre size variability, scattered necrotic and regenerating fibres, and perivascular and endomysial cellular infiltrates.

Exclusions:

Systemic sclerosis (4A42)
Overlap or undifferentiated nonorgan specific systemic autoimmune disease (4A43)
Antiphospholipid syndrome (4A45)
Vasculitis (4A44)
Lupus erythematosus (4A40)

4A41.11 Paraneoplastic polymyositis

Definition of Paraneoplastic polymyositis: Paraneoplastic is a rare cancer associated entity. It presents sub-, or acutely with proximal weakness, often including the neck flexors, dysphagia, rarely the respiratory muscles and the heart are involved. Sometimes muscle pain or myalgia occur. Myopathology shows a targeted, cell-mediated lymphocyte toxicity against muscle fibres in focal areas of inflammation within perimysial connective tissue and surrounding blood vessels. Muscle fibres may be destroyed by cytotoxic T cells.

Non-Hodgkin’s lymphoma, lung, and bladder carcinoma are the most frequently observed associated cancer types.

4A41.1Y Other specified polymyositis

4A41.1Z Polymyositis unspecified

4A41.2 Inclusion body myopathy

Definition of Inclusion body myopathy: Inclusion body myopathy (IBM) is distinguished from polymyositis (PM) and dermatomyositis (DM) on the basis of clinical and histopathological features. A characteristic clinical phenotype is characterised by insidious onset of muscle weakness over months to years, muscle weakness localised predominantly in the thigh muscles and finger flexors, and resistance to glucocorticoid treatment. Typical histopathologic features include sarcoplasmic and nuclear inclusions and rimmed vacuoles. (Kelley’s Textbook of Rheumatology, 6th Ed.)

4A41.20 Inflammatory inclusion body myositis

Definition of Inflammatory inclusion body myositis: Inclusion body miositis (IBM) is the most common idiopathic inflammatory myopathies after age 50. It typically presents with chronic insidious proximal leg and/or distal arm asymmetric muscle weakness leading to recurrent falls and loss of dexterity. Creatine kinase is up to 15 times elevated in IBM and needle electromyography mostly shows a chronic irritative myopathy. Muscle histopathology demonstrates endomysial inflammatory exudates surrounding and invading non-necrotic muscle fibres often times accompanied by rimmed vacuoles and protein deposits. Despite inflammatory muscle pathology, it likely that IBM is has a prominent degenerative component as supported by refractoriness to immunosuppressive therapy.

Exclusions:

Myasthenia gravis or certain specified neuromuscular junction disorders

4A41.21 Noninflammatory inclusion body myopathy

Definition of Noninflammatory inclusion body myopathy: Noninflammatory inclusion body myositis (IBM) is an idiopathic muscle disorder without inflammatory exudates and expression of class I major histocompatibility complex. Rimmed vacuoles and “IBM-like” filaments without inflammatory cells are described in muscle biopsy.

Exclusions:

Myasthenia gravis or certain specified neuromuscular junction disorders

4A41.2Z Inclusion body myopathy unspecified

4A41.Y Other specified idiopathic inflammatory myopathy

4A41.Z Idiopathic inflammatory myopathy unspecified

Systemic sclerosis

Definition of Systemic sclerosis: Systemic sclerosis is a systemic disorder of the connective tissue; manifested by hardening and thickening of the skin, by abnormalities involving the microvasculature and larger vessels, and by fibrotic degenerative changes in various body organs including the heart, lungs, kidneys, and gastrointestinal tract. (Arthritis Rheum 1980;23:581-590)

ICD 11 Code For Systemic sclerosis

4A42 Systemic sclerosis

Inclusions:

Systemic scleroderma

Exclusions:

Circumscribed scleroderma (EB61.0)

4A42.0 Paediatric onset systemic sclerosis

Definition of Paediatric onset systemic sclerosis: Systemic sclerosis arising before the age of 16. Involvement of internal organs is less common but arthritis and myositis are more common than in adults.

4A42.1 Diffuse systemic sclerosis

Definition of Diffuse systemic sclerosis: Diffuse cutaneous systemic sclerosis (dcSSc) is a subtype of Systemic Sclerosis (SSc) characterised by truncal and acral skin fibrosis with an early and significant incidence of diffuse involvement (interstitial lung disease, oliguric renal failure, diffuse gastrointestinal disease, and myocardial involvement).

4A42.2 Limited systemic sclerosis

Definition of Limited systemic sclerosis: Combination of calcinosis, Raynaud phenomenon, (o)oesophageal dysfunction, sclerodactyly and telangiectasia.

4A42.Z Systemic sclerosis unspecified

Overlap or undifferentiated non-organ specific systemic autoimmune disease

Definition of Overlap or undifferentiated non-organ specific systemic autoimmune disease: Nonorgan specific systemic autoimmune diseases which do not fulfil the diagnostic criteria for any single recognised disease entity.

ICD 11 Code For Overlap or undifferentiated non-organ specific systemic autoimmune disease

4A43 Overlap or undifferentiated non-organ specific systemic autoimmune disease

4A43.0 IgG4 related disease

Definition of IgG4 related disease: IgG4 related syndrome (IgG4-related disease: IgG4-RD) is a clinical disease characterised by elevated serum IgG4 concentration and tumefaction or tissue infiltration by IgG4-positive plasma cells. The diagnostic criteria for IgG4 related syndrome have been proposed, and it may be present in a certain population of patients with a wide variety of diseases, including Mikulicz disease, autoimmune pancreatitis, hypophysitis, Riedel thyroiditis, interstitial pneumonitis, interstitial nephritis, prostatitis, lymphadenopathy, retroperitoneal fibrosis, inflammatory aortic aneurysm, and inflammatory pseudo tumour.

Coded Elsewhere:

Primary cutaneous plasmacytosis (EK91.2)
Benign dermal lymphocytic or lymphoplasmacytic infiltrations or proliferations (EE90-EE91)
Type 1 IgG4 related autoimmune pancreatitis (DC33)

4A43.1 Mikulicz disease

Definition of Mikulicz disease: Mikulicz disease is a disorder first reported by Johann von Mikulicz in 1892 and characterised by symmetrical swelling of the lachrymal, submandibular, and parotid glands, with massive infiltration of these glands by mononuclear cells. Serum autoantibodies, such as anti-Ro/SS-A, are usually negative and serum IgG4 concentration may be increased. Unlike Sjögren disease, IgG4-Mikulicz disease is characterised by the formation of lymphoid follicles, but shows lower levels of lymphocytic infiltration into salivary ducts, such that their structure remains intact.

4A43.2 Sjögren syndrome

Definition of Sjögren syndrome: Sjögren syndrome is a slowly progressive, systemic inflammatory autoimmune disease affecting primarily the exocrine glands. Lymphocytic infiltrates replace functional epithelium, leading to oral and ocular dryness. Characteristic autoantibodies (e.g., anti-Ro/SS-A and/or anti-La/SS-B) are produced. The disorder can occur alone (it is then known as “primary-SS”) or in association with another autoimmune disease (it is then known as “secondary-SS”).

Coded Elsewhere:

Keratoconjunctivitis sicca (9A79)

4A43.20 Primary Sjögren syndrome

4A43.21 Secondary Sjögren syndrome

Definition of Secondary Sjögren syndrome: Secondary Sjögren syndrome is a progressive inflammatory autoimmune disease affecting the exocrine glands in the presence of other systemic autoimmune diseases, such as rheumatoid arthritis, systemic lupus erythematosus, and systemic sclerosis. Lymphocytic infiltrates replace functional epithelium, leading to oral and ocular dryness.

Coding Note:

Code also the causing condition

4A43.22 Paediatric onset Sjögren syndrome

4A43.2Y Other specified sjögren syndrome

4A43.3 Mixed connective tissue disease

Definition of Mixed connective tissue disease: Mixed connective tissue disease is an overlapping syndrome combining features of systemic lupus erythematosus, systemic sclerosis, and polymyositis with the presence of autoantibodies to U1-ribonucleoprotein. Raynaud’s phenomenon is seen in nearly all patients and pulmonary arterial hypertension is the most common cause of death in MCTD patients.

4A43.4 Diffuse eosinophilic fasciitis

Definition of Diffuse eosinophilic fasciitis: Also called Shulman disease/diffuse fasciitis, diffuse eosinophilic fasciitis is a rare idiopathic disorder associated with induration of the skin (orange-peel sign) that generally develops rapidly. It is a dermal and hypodermal sclerosis associated with fibrotic thickening of the subcutaneous adipose lobular septa, superficial fascia, and perimysium. Full thickness excisional biopsy of skin lesions revealing fibrosis of the subcutaneous fascia is generally required for diagnosis. Onset follows unusual physical exertion and trauma, especially in males.

4A43.Y Other specified overlap non-organ specific systemic autoimmune disease

4A43.Z Undifferentiated non-organ specific systemic autoimmune disease

Vasculitis

Definition of Vasculitis: Vasculitides represent a heterogenous group of diseases of multifactorial aetiology characterised by inflammatory lesions of vessels. These lesions consist of fibrinoid necrosis (necrotizing arteritis), giant cell infiltration without necrosis, immunoglobulins deposit or leukocytoclastic infiltration. The spectrum and severity of the systemic vaculitides is broad, from life or sight threatening fulminant disease to relatively minor skin disease.

ICD 11 Code For Vasculitis

4A44 Vasculitis

Coded Elsewhere:

Behçet disease (4A62)
Thrombotic microangiopathy, not elsewhere classified (3B65)

4A44.0 Rhizomelic pseudopolyarthritis

4A44.1 Aortic arch syndrome

Definition of Aortic arch syndrome: Arteritis, often granulomatous, predominantly affecting the aorta and/or its major branches. Onset usually in patients younger than 50.

4A44.2 Giant cell arteritis

Definition of Giant cell arteritis: Arteritis, often granulomatous, usually affecting the aorta and/or its major branches, with a predilection for the branches of the carotid artery. Often involves the temporal artery. Onset usually in patients older than 50 and often associated with polymyalgia rheumatica.

4A44.3 Single organ vasculitis

Definition of Single organ vasculitis: Vasculitis in arteries or veins of any size in a single organ that has no features that indicate that it is a limited expression of a systemic vasculitis. The involved organ and vessel type should be included in the name (e.g. cutaneous SVV, testicular arteritis, central nervous system vasculitis). Vasculitis distribution may be unifocal or multifocal (diffuse) within an organ. Some patients originally diagnosed with SOV will develop additional disease manifestations that warrant re-defining the case as one of the systemic vasculitides (e.g. cutaneous arteritis later becoming systemic polyarteritis nodosa, etc.).Chapel Hill Consensus Conference, 2011)

4A44.4 Polyarteritis nodosa

Definition of Polyarteritis nodosa: Polyarteritis nodosa is an immunologically mediated systemic necrotising vasculitis affecting medium-sized vessels. In a few cases, the disease appears after viral infection but in the majority of cases there is no known triggering event. The clinical manifestations involve numerous organs and lead to a general alteration in the health status including rapid weight loss, paralysis of the peripheral nerves, renal disease, and digestive problems such as haemorrhages, perforation, appendicitis and pancreatitis. Arthralgia is almost always present and myalgia occurs in half of patients. Cardiac and cerebral anomalies (cephalalgia) are also reported, as well as ocular and genital (orchitis) manifestations.

4A44.5 Mucocutaneous lymph node syndrome

Definition of Mucocutaneous lymph node syndrome: Mucocutaneous lymph node syndrome (Kawasaki disease) is a globally distributed acute vasculitis of young children affecting medium to small calibre arteries and if untreated leads to coronary artery aneurysms in about a quarter of cases. Cardinal signs include cervical lymphadenopathy, conjunctival injection, rash (maculopapular, erythrodermic or erythema multiforme-like), strawberry tongue, oropharyngeal erythema, erythema and swelling of hands and feet and periungual desquamation. The cause is unknown but thought to be environmental, possibly from viral infection. A variant of the disease has been linked to SARS CoV-2 infection.

Inclusions:

Kawasaki syndrome

4A44.6 Sneddon syndrome

Definition of Sneddon syndrome: Sneddon syndrome associates livedo reticularis and neurological signs. Livedo is permanent, cyanotic, with no infiltration, and affects the limbs, trunk and sometimes the face. Neurological signs appear later and include cerebrovascular accidents, epilepsy, vertigo and more rarely a pseudobulbar syndrome, chorea, episodes of amnesia or transient amaurosis.

4A44.7 Primary angiitis of the central nervous system

Definition of Primary angiitis of the central nervous system: In primary angiitis of the central nervous system, vasculitis is limited to the central nervous system. Primary angiitis of the central nervous system is a very rare disease, and its manifestation can be mimicked by many other diseases. Patients with primary angiitis commonly show headache, waxing and waning altered mental status, and transient ischemic attack-like events. Diagnosis is often based on angiography, although brain biopsy remains the only definitive diagnostic test.

4A44.8 Thromboangiitis obliterans

Definition of Thromboangiitis obliterans: Thromboangiitis obliterans (TAO), or Buerger’s disease, is a segmental occlusive inflammatory condition of arteries and veins, with thrombosis and recanalization of the affected vessels. It is a nonatherosclerotic inflammatory disease affecting small and medium sized arteries and veins of upper and lower extremities. TAO can be distinguished from other types of vasculitis based on its tendency to occur in young male subjects. The etiology and pathogenesis of TAO remains unknown; however, tobacco consumption plays a key role in the initiation and persistence of the disease.

4A44.9 Immune complex small vessel vasculitis

Coded Elsewhere:

Anti-glomerular basement membrane antibody mediated disease (MF85)
Susac syndrome (8A45.2Y)

4A44.90 Cryoglobulinaemic vasculitis

Definition of Cryoglobulinaemic vasculitis: Vasculitis with cryoglobulin immune deposits affecting small vessels (predominantly capillaries, venules, or arterioles) and associated with cryoglobulins in serum. Skin and glomeruli are often involved.

4A44.91 Hypocomplementaemic urticarial vasculitis

Definition of Hypocomplementaemic urticarial vasculitis: Vasculitis accompanied by urticaria and hypocomplementemia affecting small vessels (i.e., capillaries, venules, or arterioles), and associated with anti-C1q antibodies. Glomerulonephritis, arthritis, obstructive pulmonary disease, and ocular inflammation are common.(Chapel Hill Consensus Conference, 2011)

4A44.92 IgA vasculitis

Definition of IgA vasculitis: Vasculitis, with IgA1-dominant immune deposits, affecting small vessels (predominantly capillaries, venules, or arterioles). Often involves skin and gut, and frequently causes arthritis. Glomerulonephritis indistinguishable from IgA nephropathy may occur.

Inclusions:

Henoch-Schönlein purpura

Coded Elsewhere:

Respiratory disorders in IgA vasculitis (CB05.4Y)
Noninfectious enteritis or ulcer due to IgA vasculitis (DA94.Y)

4A44.9Y Other specified immune complex small vessel vasculitis

4A44.9Z Immune complex small vessel vasculitis unspecified

4A44.A Antineutrophil cytoplasmic antibody-associated vasculitis

Definition of Antineutrophil cytoplasmic antibody-associated vasculitis: Necrotizing vasculitis, with few or no immune deposits, predominantly affecting small vessels (i.e., capillaries, venules, arterioles and small arteries), associated with MPO-ANCA or PR3-ANCA. Not all patients have ANCA. Add a prefix indicating ANCA reactivity, e.g. PR3-ANCA, MPO-ANCA, ANCA-negative.

4A44.A0 Microscopic polyangiitis

Definition of Microscopic polyangiitis: Necrotizing vasculitis, with few or no immune deposits, predominantly affecting small vessels (i.e., capillaries, venules, or arterioles). Necrotizing arteritis involving small and medium sized arteries may be present. Necrotizing glomerulonephritis is very common. Pulmonary capillaritis often occurs. Granulomatous inflammation is absent.

Inclusions:

Microscopic polyarteritis

Exclusions:

Polyarteritis nodosa (4A44.4)

4A44.A1 Granulomatosis with polyangiitis

Definition of Granulomatosis with polyangiitis: Necrotizing granulomatous inflammation usually involving the upper and lower respiratory tract, and necrotizing vasculitis affecting predominantly small to medium-sized vessels (e.g., capillaries, venules, arterioles, arteries and veins). Necrotizing glomerulonephritis is common . (Arthritis Rheum 1990;33:1101-1107)

Inclusions:

Wegener granulomatosis

4A44.A2 Eosinophilic granulomatosis with polyangiitis

Definition of Eosinophilic granulomatosis with polyangiitis: Eosinophil-rich and necrotizing granulomatous inflammation often involving the respiratory tract, and necrotizing vasculitis predominantly affecting small to medium-sized vessels, and associated with asthma and eosinophilia. ANCA is most frequent when glomerulonephritis is present. (Arthritis Rheum 1990;33:1094-1100)

Inclusions:

Churg-Strauss syndrome

4A44.AY Other specified antineutrophil cytoplasmic antibody-associated vasculitis

4A44.AZ Antineutrophil cytoplasmic antibody-associated vasculitis unspecified

4A44.B Leukocytoclastic vasculitis

Definition of Leukocytoclastic vasculitis: Leukocytoclastic vasculitis (hypersensitivity vasculitis; hypersensitivity angiitis) is a histopathological term commonly used to denote a small-vessel vasculitis. It may be localised to the skin or may manifest in other organs. The internal organs affected most commonly include the joints, the gastrointestinal tract, and the kidneys. The prognosis is good in the absence of internal involvement. Leukocytoclastic vasculitis has many causes including infections, drugs and systemic autoimmune diseases but no cause is identified in up to 50% of patients with this condition.

4A44.B0 Cutaneous leukocytoclastic vasculitis

Definition of Cutaneous leukocytoclastic vasculitis: Skin-limited small vessel leucocytoclastic vasculitis of unspecified or unknown aetiology

4A44.BY Other specified leukocytoclastic vasculitis

4A44.BZ Leukocytoclastic vasculitis unspecified

4A44.Y Other specified vasculitis

4A44.Z Vasculitis unspecified

Antiphospholipid syndrome

Definition of Antiphospholipid syndrome: Antiphospholipid syndrome, also known as Hughes syndrome, is a systemic autoimmune condition characterised by the presence of antiphospholipid antibodies (aPL) in the serum of patients with thrombotic events and/or recurrent pregnancy complications.

ICD 11 Code For Antiphospholipid syndrome

4A45 Antiphospholipid syndrome

4A45.0 Primary antiphospholipid syndrome

4A45.1 Secondary antiphospholipid syndrome

Coding Note:

Code also the causing condition

4A45.2 Antiphospholipid syndrome in pregnancy

4A45.3 Lupus anticoagulant-hypoprothrombinaemia syndrome

4A45.Z Antiphospholipid syndrome unspecified

Other specified non-organ specific systemic autoimmune disorders

ICD 11 Code For Other specified non-organ specific systemic autoimmune disorders

4A4Y Other specified non-organ specific systemic autoimmune disorders