World Health Organization

The World Health Organization (WHO) "directs and coordinates" international health within the United Nations. It was established on 7th April 1948, and is headquartered in Geneva, Switzerland. The WHO works with 194 member states across the world.

The International Statistical Classification of Diseases and Related Health Problems (ICD) is the "the bedrock for health statistics" and is maintained by WHO. It aims to classify every possible injury or disease a person may experience, including causes of death.

First recognition of ME/CFS
Myalgic encephalomyelitis (ME) has been recognized by the World Health Organization as a neurological disease since 1969, when it published the ICD-8 classification of diseases using code 323 for myalgic encephalomyelitis. The ICD-8 listing for ME/CFS is:


 * VI. DISEASES OF THE NERVOUS SYSTEM AND SENSE ORGANS
 * Inflamatory diseases of central nervous system (320-324)
 * Encephalitis, myelitis, and encephalomyelitis (except acute infectious As 343)
 * Encephalomyelitis (chronic) (disseminated, acute) (granulomatous)
 * (hemarrhagic necrotizing. acute)
 * (myalgic, benign)
 * (postexanthematous)
 * (postinfectious) (see also Encephalitis) 343)

The United States edition of the ICD-8 included both myalgic encephalomyelitis (ME) and what is now known as postviral fatigue syndrome (PVFS), classifying both with code 323:


 * Encephalomyelitis (chronic) (disseminated, acute) (Branulomalous)
 * (hemorrhagic necrotizing, acute)
 * (myalgic, benign)
 * (postexanthematous)
 * (postinfectious) (see also Encephalitis).

The ICD-8 did not include any alternative names for myalgic encephalomyelitis although postinfectious encephalomyelitis could be classified under the same code; fatigue-related alternative names were not added in any later revisions. The alternative name chronic fatigue syndrome (CFS) was not in use at this time; it was proposed in 1988 by the Centers for Disease Control, which adopted new diagnostic criteria at the same time.

The current version of the ICD is the ICD-10; the newer ICD-11 has been published but is expected to be in widespread use within the next few years.

ICD-9 classification of ME/CFS
In the ICD-9, which was published in 1989, the entry for myalglc encephalomyelitis is uses code 323.9:


 * DISEASES OF THE NERVOUS SYSTEM AND SENSE ORGANS
 * Encephalomyelitis (chronic) (granulomatous) (hemorrhagic necrotizing, acute) (myalgic, benign) (see also Encephalitis) 323.9
 * - acute disseminated (postinfectious) 136.9 323.6*
 * - - postimmunization 323.5
 * — due to or resulting from vaccination (any) 323.5
 * - postchickenpox 052 323.6*
 * - postmeasles 055.0 323.6*
 * - postvaccinal 323.5
 * - rubella 056.0 323.4*

ICD-10 classification of ME/CFS
The ICD-10 lists myalgic encephalomyelitis, chronic fatigue syndrome, and postviral syndrome (PVFS) as the same neurological disease, within the neurological disorders section.


 * Diseases of the nervous system
 * Other disorders of brain
 * Other disorders of the nervous system


 * G93.3 Postviral fatigue syndrome
 * Benign myalgic encephalomyelitis

Myalgic encephalomyelitis (ME) has been classified by the WHO as a neurological disease since 1969 and has occurred in both epidemic and sporadic form since at least the 1930s, although is probably much older.

Malaise and fatigue
The World Health Organization has stated that ME and CFS can only be classed as a neurological disorder and cannot be classified under the following "malaise and fatigue" diagnosis (in the General signs, symptoms and abnormal findings), or as neurasthenia or Fatigue syndrome in the mental and behavioral disorders category:

R53.83 Malaise and fatigue categorizies "lethargy" and  "tiredness" which are regarded as "Signs, symptoms and abnormal findings" rather than a specific disease.

F48.0 Neurasthenia

This is classed as a neurotic (anxiety) disorder, within the mental disorders section of the ICD-10; it is describes this as "increased fatigue" which may be after mental effort, or emphasizing "feelings of bodily or physical weakness and exhaustion after only minimal effort", with an inability to relax and "a feeling of muscular aches and pains".

In the ICD-10 this excludes burn-out (Z73.0), malaise and fatigue (R53) and postviral fatigue syndrome (G93.3).

Chronic fatigue with no known cause which does not meet the criteria for chronic fatigue syndrome is referred to as either idiopathic chronic fatigue or a medically unexplained symptom in medical literature.

ICD-10 coding manual
The ICD-10-CM used in the United States is a coding manual used for insurance purposes, differs from other countries, and includes two different classifications, each with virtually identical symptoms:
 * R53.82 Chronic fatigue, unspecified, which is given the alternative name Chronic Fatigue Syndrome and classified "not otherwise specified", and excludes Myalgic Encephalomyelitis and Chronic Fatigue Syndrome (and anything that can be classified as G93.3),
 * G93.3 Postviral Fatigue Syndrome, alternatively known as Benign Myalgic Encephalomyelitis or Chronic Fatigue Syndrome. ICD 9 (and 10) "consider NOS the physician's fault: The documentation does not provide enough information to assign a more specific diagnosis code."

ICD-11
In the more recently released ICD-11, Postviral fatigue syndrome (PVFS) is the name used for benign myalgic encephalomyelitis and chronic fatigue syndrome, and remains a disorder of the nervous system.

08 Diseases of the nervous system
 * Other disorders of the nervous system
 * 8E49 Postviral fatigue syndrome
 * Benign myalgic encephalomyelitis
 * chronic fatigue syndrome

ICD Diagnostic coding
ICD-10 is the 10th revision of the ICD and was first published in 1992. The ICD-11 was published in July 2018, but is not implemented in most countries at present.

Different countries' government healthcare systems might use different codes depending on their interpretation of some diseases, illnesses, and syndromes but still working within the ICD code structure. When using ICD10Data.com, certain pages will display a country's flag indicating the diagnostic coding used by that nation's healthcare system. Additionally, a country does not have to officially implement the latest ICD release; the United States delayed the implementation of ICD-10 for over 20 years before implementing it's own WHO-approved adaption, the ICD-10-CM.

ICD-10-CM
United States


 * G93.3 Postviral fatigue syndrome and benign myalgic encephalomyelitis.

ICD-10-CM G93.3 is grouped within Diagnostic Related Group(s) (MS-DRG v35.0):


 * 947 Signs and symptoms with mcc
 * 948 Signs and symptoms without mcc

Convert G93.3 to ICD-9-CM

Code History


 * 2016 (effective 10/1/2015): New code (first year of non-draft ICD-10-CM)
 * 2017 (effective 10/1/2016): No change
 * 2018 (effective 10/1/2017): No change

Code annotations containing back-references to G93.3:


 * Type 1 Excludes: A85, R53.82
 * Type 2 Excludes: G04

Diagnosis Index entries containing back-references to G93.3:


 * Akureyri's disease G93.3
 * Disease, diseased - see also Syndrome
 * Iceland G93.3
 * Encephalomyelitis G04.90 - see also Encephalitis
 * benign myalgic G93.3
 * myalgic, benign G93.3
 * Neuromyasthenia G93.3 (epidemic) (postinfectious)
 * Syndrome - see also Disease
 * postviral NEC G93.3
 * fatigue G93.3

ICD-11 (2018)

 *  8E49 Postviral fatigue syndrome 

All ancestors up to top


 * 08 Diseases of the nervous system


 * Other disorders of the nervous system
 * 8E49 Postviral fatigue syndrome

Inclusions


 * Benign myalgic encephalomyelitis
 * chronic fatigue syndrome

The ICD-11 no longer has a fatigue syndrome of any kind in the "Mental and Behavioral Disorders" section. Neurasthenia is not mentioned in any section. In response to the Wessely school's textbook which incorrectly stated that chronic fatigue syndrome (CFS) can be classed as a mental disorder, Audre L'Hours from WHO has stated that a disorder can only be classed under one rubic, and that all WHO countries must follow the WHO classification of CFS or ME as a neurological disorder only.

Dr Tarun Dua proposed moving Myalgic Encephalomyelitis from the Neurological Disorders section to Symptoms, signs or clinical findings of the musculoskeletal system, which would have re-classified ME/CFS as medically unexplained physical symptoms rather than a specific, neurological disease: this proposal was rejected.

ICD-10-CM
United States


 * R53.82 is for Chronic fatigue, unspecified under ICD-10-CM Diagnosis Code.

R53.82 (ICD-10-CM) is grouped within Diagnostic Related Group(s) (MS-DRG v35.0):


 * 947 Signs and symptoms with mcc
 * 948 Signs and symptoms without mcc


 * Convert R53.82 to ICD-9-CM


 * Code History
 * 2016 (effective 10/1/2015): New code (first year of non-draft ICD-10-CM)
 * 2017 (effective 10/1/2016): No change
 * 2018 (effective 10/1/2017): No change


 * Code annotations containing back-references to R53.82:
 * Type 1 Excludes: G93.3


 * Diagnosis Index entries containing back-references to R53.82:
 * Fatigue R53.83
 * chronic R53.82
 * Syndrome - see also Disease
 * fatigue
 * chronic R53.82

ICD-11 (2019)

 *  8E49 Postviral fatigue syndrome 

All ancestors up to top


 * 08 Diseases of the nervous system


 * Other disorders of the nervous system
 * 8E49 Postviral fatigue syndrome

Inclusions


 * Benign myalgic encephalomyelitis
 * chronic fatigue syndrome

DSM
The American diagnostic manual for mental and behavioral disorders, known as the DSM-5, does not contain include myalgic encephalomyelitis or chronic fatigue syndrome, because they are not mental health conditions.

History with Fibromyalgia
The WHO ICD-10 lists fibromyalgia as a "disease of the musculoskeletal system and connective tissue," diagnostic code M79.7.

ICD-10-CM

 * M79.7 Fibromyalgia


 * Fibromyositis
 * Fibrositis
 * Myofibrositis

In 2015, the United States adopted the 1992 ICD-10 and fibromyalgia as a diagnosis.

ICD-11 (2019)
Fibromyalgia was renamed to Chronic Widespread Pain in the ICD-11 update, with fibromyalgia retained as an indexed term. The ICD-11 uses diagnostic code MG30.1 Chronic widespread pain for fibromyalgia.


 * MG30.01 Chronic widespread pain

Parent


 * MG30.0 Chronic primary pain

Description


 * "Chronic widespread pain (CWP) is diffuse pain in at least 4 of 5 body regions and is associated with significant emotional distress (anxiety, anger/frustration or depressed mood) or functional disability (interference in daily life activities and reduced participation in social roles). CWP is multifactorial: biological, psychological and social factors contribute to the pain syndrome. The diagnosis is appropriate when the pain is not directly attributable to a nociceptive process in these regions and there are features consistent with nociplastic pain and identified psychological and social contributors."

Inclusions


 * Fibromyalgia

Exclusions


 * Acute pain (MG31)

DSM
Fibromyalgia is not included in the American DSM-5 manual of mental and behavioral disorders because it is a physical rather than psychological illness. Fibromyalgia is also classified within a chapter of physical health conditions, and not in the mental and behavioral chapter of the ICD diagnostic manual.

Online presence
The WHO uses social media in many languages.

English language

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 * Website

Learn more

 * 2009, WHO ICD in relation to M.E. and "CFS"—Short via The Hummingbirds' Foundation for ME
 * History of Chronic Fatigue Syndrome - International Classifications via Wikipedia