8E4A

ICD-11 MMS 2026-01

Paraneoplastic or autoimmune disorders of the nervous system

Description

Paraneoplastic and autoimmune disorders of the nervous system result from a targeted immune attack on neurons or glial cells in the central (e.g. encephalopathy, ataxia, myelitis) or peripheral nervous systems (peripheral or autonomic neuropathies, neuromuscular junction disorders or myopathy). In the paraneoplastic context, this attack is a consequence of a potentially effective tumour immune response initiated by onco-neural antigens derived from a systemic cancer. In the non-paraneoplastic context termed autoimmune the etiology remains elusive though increasing evidence indicates a preceding infectious trigger in at least some cases. These disorders are commonly multifocal causing injury and symptoms arising from involvement at many levels of the nervous system. A personal or family history of autoimmunity is often found. Accompanying neural and non-organ specific (thyroid peroxidase [TPO] antibodies) autoantibodies may be found. The neural autoantibody profile may be predictive of a specific cancer type and may be associated with a particular neurological phenotype. Exclusion of alternative etiologies (e.g. infections) is important. Response to immunotherapy may support the diagnosis.

Exclusions from above levels

  • 05 – Endocrine, nutritional or metabolic diseases
  • 18 – Complications of pregnancy, childbirth and the puerperium
  • 19 – Certain conditions originating in the perinatal period
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  • 22 – Injury, poisoning or certain other consequences of external causes

Child codes

  • 8E4A.0 – Paraneoplastic or autoimmune disorders of the central nervous system, brain or spinal cord
  • 8E4A.1 – Paraneoplastic or autoimmune disorders of the peripheral or autonomic nervous system
  • 8E4A.2 – Paraneoplastic or autoimmune neuromuscular transmission disorders
  • 8E4A.3 – Paraneoplastic or autoimmune disorders of the muscle
  • 8E4A.Y – Other specified paraneoplastic or autoimmune disorders of the nervous system
  • 8E4A.Z – Paraneoplastic or autoimmune disorders of the nervous system, unspecified

Sibling codes

  • 8E40 – Disorders of the meninges excluding infection
  • 8E41 – Pachymeningitis
  • 8E42 – Superficial siderosis of the nervous system
  • 8E43 – Pain disorders
  • 8E44 – Post anoxic brain damage
  • 8E45 – Locked-in syndrome
  • 8E46 – Reye syndrome
  • 8E47 – Encephalopathy, not elsewhere classified
  • 8E48 – Encephalitis, not elsewhere classified
  • 8E49 – Postviral fatigue syndrome

Foundation entity

Paraneoplastic or autoimmune disorders of the nervous system – http://id.who.int/icd/entity/1058231555

Allowed postcoordination axes

Part of: 08: Diseases of the nervous system