International Classification of Diseases (ICD-11)

Except as indicated above, it may not be reviewed, abstracted, reproduced, transmitted, distributed, translated or adapted, in part or in whole, in any form or by any means. WHO will not issue any authorizations (permissions, translation rights, etc.) for use of ICD-11.  ICD-11 was approved at the recent Seventy-second World Health Assembly on May 25th 2019, and it will be formally published by WHO.

WHO initially granted CPI permission to reproduce the codes mentioned below, and we acknowledge the original source as follows: ICD-11 (version for implementation) Geneva: World Health Organization, 2018. ICD-11 codes may be subject to change.

What is ICD-11

The International Classification of Disease, Eleventh Revision (ICD-11) is a system of medical coding created by the World Health Organization (WHO) for documenting diagnoses, diseases, signs and symptoms and social circumstances. 

Disclaimer: Dear reader, while every attempt has been made to represent accurate information in accordance to the WHO’s publication of ICD 11, this document should not be used for diagnostic purposes and is for reference only. This is not an exhaustive list of all conditions please refer to the WHO website for the original, official document. www.who.int CHAPTER 21

Symptoms, signs or clinical findings, not elsewhere classified Pain (BlockL3‑MG3)

MG30.0 Chronic primary pain

MG30.1 Chronic cancer related pain

MG30.2 Chronic postsurgical or post traumatic pain

MG30.3 Chronic secondary musculoskeletal pain

MG30.4 Chronic secondary visceral pain

MG30.5 Chronic neuropathic pain

MG30.6 Chronic secondary headache or orofacial pain

MG30.Y Other specified chronic pain

MG30.Z Chronic pain, unspecified

MG30 Chronic pain Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage. Chronic pain is pain that persists or recurs for longer than 3 months. Note: This code should be used if a pain condition persists or recurs for longer than 3 months.  Exclusions: Acute pain (MG31) 

MG30.0 Chronic primary pain Chronic primary pain is chronic pain in one or more anatomical regions that is characterized by significant emotional distress (anxiety, anger/frustration or depressed mood) or functional disability (interference in daily life activities and reduced participation in social roles). Chronic primary pain is multifactorial: biological, psychological and social factors contribute to the pain syndrome. The diagnosis is appropriate independently of identified biological or psychological contributors unless another diagnosis would better account for the presenting symptoms. Other chronic pain diagnoses to be considered are chronic cancer-related pain, chronic postsurgical or posttraumatic pain, chronic neuropathic pain, chronic secondary headache or orofacial pain, chronic secondary visceral pain and chronic secondary musculoskeletal pain. Exclusions: Acute pain (MG31) Coded Elsewhere: Complex regional pain syndrome (8D8A.0)

MG30.00 Chronic primary visceral pain Chronic primary visceral pain is chronic pain localized in the thoracic, abdominal or pelvic region, and that is associated with significant emotional distress or functional disability. The distinct anatomical location is compatible with typical referral pain patterns from specific internal organs. The symptoms are not better explained by a diagnosis of chronic secondary visceral pain. Chronic primary visceral pain is multifactorial: biological, psychological and social factors contribute to the pain syndrome. The diagnosis is appropriate independently of identified biological or psychological contributors unless another diagnosis would better account for the presenting symptoms.

MG30.01 Chronic widespread pain 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) [1]. 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 [2] and identified psychological and social contributors. Inclusions: Fibromyalgia Exclusions: Acute pain (MG31)

MG30.02 Chronic primary musculoskeletal pain Chronic primary musculoskeletal pain is chronic pain in the muscles, bones, joints or tendons that is characterized by significant emotional distress (anxiety, anger/frustration or depressed mood) or functional disability (interference in daily life activities and reduced participation in social roles). Chronic primary musculoskeletal pain is multifactorial: biological, psychological and social factors contribute to the pain syndrome. The diagnosis is appropriate independently of identified biological or psychological contributors unless another diagnosis would better account for the presenting symptoms. Other chronic musculoskeletal pain diagnoses to be considered are those listed under chronic secondary musculoskeletal pain. Exclusions: Acute pain (MG31)

MG30.03 Chronic primary headache or orofacial pain Chronic primary headache or orofacial pain is defined as headache or orofacial pain that occurs on at least 50% of the days during at least three months. It is characterized by significant emotional distress (anxiety, anger/frustration or depressed mood) or functional disability (interference in daily life activities and reduced participation in social roles). Chronic primary headache or orofacial pain is multifactorial: biological, psychological and social factors contribute to the pain syndrome. The diagnosis is appropriate independently of identified biological or psychological contributors unless another diagnosis would better account for the presenting symptoms. Other chronic headache or orofacial pain diagnoses to be considered are listed under chronic secondary headache and orofacial pain. The duration of pain per day is at least 4 hours (untreated) or several shorter attacks per day occur. Exclusions: Headache disorders (BlockL1‑8A8) Coded Elsewhere: Chronic migraine (8A80.2) Tension-type headache (8A81) Trigeminal autonomic cephalalgias (8A82) Burning mouth syndrome (DA0F.0)

MG30.0Y Other specified chronic primary pain

MG30.0Z Chronic primary pain, unspecified

MG30.1 Chronic cancer related pain Chronic cancer-related pain is pain caused by the primary cancer itself or metastases (chronic cancer pain) or its treatment (chronic post-cancer treatment pain). It is distinct from pain caused by co-morbid disease [1-3]. It should be highly probable that the pain is due to cancer or its treatment; if its genesis is vague, consider using codes in the section of Primary pain.

MG30.10 Chronic cancer pain Chronic cancer pain is chronic pain caused by the primary cancer or metastases. It should be highly probable that the pain is due to cancer; if its genesis is vague, consider using codes in the section of chronic primary pain.

MG30.11 Chronic post cancer treatment pain Chronic post-cancer treatment pain is pain caused by any treatment given to treat the primary tumour or metastases. The most common forms are: (i) Chronic painful chemotherapy-induced polyneuropathy (CIPN): chronic peripheral neuropathic pain caused by oral or intravenous chemotherapy. (ii) Chronic post-radiotherapy pain: chronic pain caused by delayed local damage to the nervous system in the field of radiotherapy. It is distinct from pain caused by tumour recurrence or co-morbid disease. Other treatments include surgery and hormonal therapy.

MG30.1Y Other specified chronic cancer related pain

MG30.1Z Chronic cancer related pain, unspecified

MG30.2 Chronic postsurgical or post traumatic pain Chronic postsurgical and post traumatic pain is pain developing or increasing in intensity after a surgical procedure or a tissue injury (involving any trauma including burns) and persisting beyond the healing process, i.e. at least 3 months after surgery or tissue trauma. The pain is either localized to the surgical field or area of injury, projected to the innervation territory of a nerve situated in this area, or referred to a dermatome (after surgery/injury to deep somatic or visceral tissues). Other causes of pain including infection, malignancy etc. need to be excluded as well as pain continuing from a pre-existing pain problem. Dependent on type of surgery, chronic postsurgical and posttraumatic pain often may be neuropathic pain. Even if neuropathic mechanisms are crucial, the type of pain should be diagnosed here. The postsurgical or posttraumatic etiology of the pain should be highly probable; if it is vague, consider using codes in the section of chronic primary pain.

MG30.20 Chronic post traumatic pain Chronic post traumatic pain is pain developing or increasing in intensity after a tissue injury (involving any trauma including burns) and persisting beyond the healing process, i.e. at least 3 months after the tissue trauma. The pain is either localized to the area of injury, projected to the innervation territory of a nerve situated in this area, or referred to a dermatome (after surgery/injury to deep somatic or visceral tissues). Other causes of pain including infection, malignancy etc. need to be excluded as well as pain continuing from a pre-existing pain problem. Chronic posttraumatic pain often may be neuropathic pain. Even if neuropathic mechanisms are crucial, this type of pain should be diagnosed here. The posttraumatic etiology of the pain should be highly probable; if it is vague, consider using codes in the section of chronic primary pain. Coded Elsewhere: Whiplash associated disorder with complaint of neck pain, stiffness or tenderness only (NA23.40) Whiplash associated disorder with complaint of neck pain with musculoskeletal signs (NA23.41) Whiplash associated disorder with complaint of neck pain with neurological signs (NA23.42) Chronic central neuropathic pain associated with spinal cord injury (MG30.50) Chronic central neuropathic pain associated with brain injury (MG30.50)

MG30.21 Chronic postsurgical pain Chronic postsurgical pain is chronic pain developing after a surgical procedure and persisting beyond the healing process, i.e. at least 3 months after surgery. The pain is either localized to the surgical field, projected to the innervation territory of a nerve situated in this area, or referred to a dermatome (after surgery/injury to deep somatic or visceral tissues). Other causes of pain including infection, malignancy etc. need to be excluded as well as pain continuing from a pre-existing pain problem. The postsurgical etiology of the pain should be highly probable; if it is vague, consider using codes in the section of chronic primary pain. Dependent on type of surgery, chronic postsurgical pain often may be neuropathic pain. Even if neuropathic mechanisms are crucial, this type of pain should be diagnosed here. The postsurgical etiology of the pain should be highly probable; if it is vague, consider using codes in the section of chronic primary pain.

MG30.2Y Other specified chronic postsurgical or post traumatic pain

MG30.2Z Chronic postsurgical or post traumatic pain, unspecified

MG30.3 Chronic secondary musculoskeletal pain Chronic secondary musculoskeletal pain is chronic pain arising from bone(s), joint(s), muscle(s), vertebral column, tendon(s) or related soft tissue(s). It is a heterogeneous group of chronic pain conditions originating in persistent nociception in joint, bone, muscle, vertebral column, tendons and related soft tissues, with local and systemic etiologies, but also related to deep somatic lesions. The pain may be spontaneous or movement-induced. If the pain is related to visceral lesions, it should be considered whether a diagnosis of chronic visceral pain is appropriate; if it is related to neuropathic mechanisms, it should be coded under chronic neuropathic pain; and if the pain mechanisms are non-specific, chronic musculoskeletal pain should be coded under chronic primary pain. Exclusions: Acute pain (MG31) Chronic neuropathic pain (MG30.5) Chronic primary pain (MG30.0) Chronic secondary visceral pain (MG30.4)

MG30.30 Chronic secondary musculoskeletal pain from persistent inflammation Chronic secondary musculoskeletal pain from persistent inflammation is chronic pain due to inflammatory mechanisms in joint(s), bone(s), tendon(s), muscle(s), soft tissue(s) or vertebral column. The pain may be spontaneous or movement-induced. It is characterized by clinical features of inflammation, including increased sensitivity of the part to stimuli.

MG30.31 Chronic secondary musculoskeletal pain associated with structural changes Chronic secondary musculoskeletal pain associated with structural changes is chronic pain of unknown mechanism(s) that is attributable to anatomical changes in joint(s), bone(s) or tendon(s). The structural change needs to be inferred from clinical examination and/or demonstrable on imaging. The pain may be spontaneous or movement-induced. It is characterized by clinical features such as swelling, allodynia or restricted movement.

MG30.32 Chronic secondary musculoskeletal pain due to disease of the nervous system Chronic secondary musculoskeletal pain due to diseases of the nervous system is chronic pain localized in joint(s), bone(s), tendon(s) or muscle(s) that is related to peripheral or central neurological disorders classified elsewhere. It includes pain due to altered motor function and altered sensory function. Altered biomechanical function due to the neurological disease is responsible for the activation of nociceptors in musculoskeletal tissue. The pain may be spontaneous or movement-induced. Note: Code also the underlying condition

MG30.3Y Other specified chronic secondary musculoskeletal pain

MG30.3Z Chronic secondary musculoskeletal pain, unspecified

MG30.4 Chronic secondary visceral pain Chronic visceral pain is persistent or recurrent pain originating from internal organs of the head/neck region and of the thoracic, abdominal and pelvic cavities. The visceral etiology of the pain should be highly probable; if it is vague, consider using codes in the section of Chronic Primary Pain. Exclusions: Neuropathic pain (8E43.0)

MG30.40 Chronic visceral pain from mechanical factors Chronic visceral pain from mechanical factors is chronic pain deriving from a) the obstruction of hollow viscera as a consequence of internal migrating obstacles (e.g., stones) or stenosis, with dilation above the obstacle/stenosis or b) from the traction of ligaments and vessels of internal organs or the external compression of internal organs.

MG30.41 Chronic visceral pain from vascular mechanisms Chronic visceral pain from vascular mechanisms is chronic visceral pain due to alterations of arterial and/or venous blood vessels to/from viscera of the head/neck region, thoracic, abdominal and pelvic cavities or pain conditions of the vascular system producing pain in other locations.

MG30.42 Chronic visceral pain from persistent inflammation Chronic visceral pain from persistent inflammation is chronic pain due to long lasting inflammation of internal organs of the head/neck region and of the thoracic, abdominal, or pelvic cavities. MG30.4Y Other specified chronic secondary visceral pain

MG30.4Z Chronic secondary visceral pain, unspecified

MG30.5 Chronic neuropathic pain Chronic neuropathic pain is chronic pain caused by a lesion or disease of the somatosensory nervous system. The pain may be spontaneous or evoked, as an increased response to a painful stimulus (hyperalgesia) or a painful response to a normally nonpainful stimulus (allodynia). The diagnosis of chronic neuropathic pain requires a history of nervous system injury or disease and a neuroanatomically plausible distribution of the pain. Negative (for example, decreased or loss of sensation) and positive sensory symptoms or signs (for example, allodynia or hyperalgesia) indicating the involvement of the somatosensory nervous system must be compatible with the innervation territory of the affected nervous structure. Coded Elsewhere: Trigeminal neuralgia (8B82.0) Postherpetic neuralgia (1E91.5) Causalgia (8D8A.01)

MG30.50 Chronic central neuropathic pain Chronic central neuropathic pain is chronic pain caused by a lesion or disease of the central somatosensory nervous system. The pain may be spontaneous or evoked, as an increased response to a painful stimulus (hyperalgesia) or a painful response to a normally nonpainful stimulus (allodynia). The diagnosis of central neuropathic pain requires a history of central nervous system injury or disease and a neuroanatomically plausible distribution of the pain. Negative (e.g., decreased or loss of sensation) and positive sensory symptoms or signs (e.g., allodynia or hyperalgesia) indicating the involvement of the central somatosensory nervous system must be compatible with the innervation territory of the affected nervous structure.

MG30.51 Chronic peripheral neuropathic pain Chronic peripheral neuropathic pain is chronic pain caused by a lesion or disease of the peripheral somatosensory nervous system. The pain may be spontaneous or evoked, as an increased response to a painful stimulus (hyperalgesia) or a painful response to a normally nonpainful stimulus (allodynia). The diagnosis of peripheral neuropathic pain requires a history of peripheral nervous system injury or disease and a neuroanatomically plausible distribution of the pain. Negative (e.g., decreased or loss of sensation) and positive sensory symptoms or signs (e.g., allodynia or hyperalgesia) indicating the involvement of the peripheral somatosensory nervous system must be compatible with the innervation territory of the affected nervous structure. Coded Elsewhere: Trigeminal neuralgia (8B82.0) Postherpetic neuralgia (1E91.5)

MG30.5Y Other specified chronic neuropathic pain

MG30.5Z Chronic neuropathic pain, unspecified

MG30.6 Chronic secondary headache or orofacial pain Chronic secondary headache and orofacial pain comprises all headache and orofacial pain disorders that have underlying causes and occur on at least 50% of the days during at least three months. The duration of pain per day is at least 4 hours (untreated) or several shorter attacks per day occur. If the etiology is vague, consider using codes in the section of chronic primary pain. Exclusions: Acute pain in the face, not elsewhere classified (MG31.0) Acute headache, not elsewhere classified (MG31.1) Coded Elsewhere: Secondary headache (8A84) Acute headache attributed to traumatic injury to the head (8A84.0) Persistent headache attributed to traumatic injury to the head (8A84.1) Headache attributed to injury to the head or neck (8A84.Y) Headache attributed to cranial or cervical vascular intracranial disorder (8A84.Y) Headache attributed to nonvascular intracranial disorder (8A84.Y) Headache attributed to disorder of homeostasis (8A84.Y) Headache or facial pain attributed to disorder of the face or neck (8A84.Y) Headache attributed to a substance (8A84.Y) Headache attributed to substance withdrawal (8A84.Y) Medication-overuse headache (8A84.Y)

MG30.60 Chronic secondary orofacial pain Chronic secondary orofacial pain comprises orofacial pain disorders that have a clear underlying cause and that occur on at least 50% of the days during at least three months. Pain duration (untreated) is variable ranging from hours to several shorter attacks per day. Note: Each distinct type, subtype or sub form of orofacial pain must be separately diagnosed and coded. When there is more than one diagnosis, these should be listed in the order of significance and importance to the patient. Most chronic orofacial pain disorders can also be found in the chapter “Diseases of the nervous system”. If the orofacial pain disorder is the primary diagnosis of the patient, the code of the neurological chapter should be used. Otherwise, both codes can be used.

MG30.61 Chronic dental pain Chronic dental pain is chronic pain that is caused by a disorder involving the teeth or associated tissues (pulpal, periodontal or gingival pain) and that occurs for two hours or more per day on at least 50% of the days during at least three months. The typical causative factor will be caries or trauma to a tooth or teeth or associated tissues. In addition to clinical examination, imaging (intraoral x-rays, CT scans etc.) may facilitate the correct diagnosis. If the etiology is vague, consider using codes in the section of chronic primary pain.

MG30.62 Chronic headache or orofacial neuropathic pain

MG30.63 Headache or orofacial pain attributed to chronic secondary temporomandibular disorders Chronic secondary temporomandibular disorder pain is chronic pain in the temporomandibular joint(s) or masseter or temporalis muscle(s) attributed to persistent inflammation (due to e.g. infection, crystal deposition or autoimmune disorders), structural changes (such as osteoarthritis or spondylosis), injury, or diseases of the nervous system It occurs on at least 50% of the days during at least three months. The duration of pain per day is at least 4 hours (untreated) or several shorter attacks per day occur. If the etiology is vague, consider using codes in the section of chronic primary pain.

MG30.6Y Other specified chronic secondary headache or orofacial pain MG30.6Z Chronic secondary headache or orofacial pain, unspecified

MG30.Y Other specified chronic pain MG30.Z Chronic pain, unspecified Other Conditions Which May be of Interest: 8E43.0 Neuropathic pain Parent • 8E43 Pain disorders Description Neuropathic pain is described as electric, burning, or shock like, caused by metabolic, nutritional, infectious, genetic, autoimmune, and/or vasculitic processes. The pain may occur spontaneously, without provocation, or be provoked by noxious or nonnoxious stimuli. Pain is characteristic of small fibre neuropathy, but even in large fibre neuropathies, a sufficient number of small fibres may be damaged to cause pain. Neuropathic pain usually affects distal skin and subcutaneous structures. The pain may be constant or intermittent, and may be described as searing, burning, or icy cold. Complex regional pain syndrome follows trauma and comprises regional pain, sensory changes, abnormalities of temperature, sudomotor activity, colour changes of the skin, and edema. Coded Elsewhere • Complex regional pain syndrome (8D8A.0)

8E43.00 Phantom limb syndrome Phantom limb pain is the perception of sensations, including pain, in a limb that has been amputated or a body part that has been removed. These sensations may include a specific position, shape, or movement of the phantom, feelings of warmth or cold, itching, tingling, or electric sensations, and other paraesthesias.

8E43.0Y Other specified neuropathic pain

8E43.0Z Neuropathic pain, unspecified

8E43.Y Other specified pain disorders

8E43.Z Pain disorders, unspecified Movement disorders Parent • 08 Diseases of the nervous system Description This is a group of involuntary movement disorders. Coded Elsewhere • Restless legs syndrome (7A80) • Periodic limb movement disorder (7A81)

8E49 Postviral fatigue syndrome Parent • Other disorders of the nervous system Show all ancestors Inclusions • Benign myalgic encephalomyelitis • chronic fatigue syndrome

Postprocedural disorders of the nervous system Parent • 08 Diseases of the nervous system Coded Elsewhere • Injury or harm arising from surgical or medical care, not elsewhere classified (NE80-NE8Z) • Post dural puncture headache (8A84.Y) • Dural graft-associated Creutzfeldt-Jakob Disease (8E01.0)

Headache disorders (BlockL1‑8A8) Coded Elsewhere: Headache, not elsewhere classified (MB6Y)

8A80 Migraine A primary headache disorder, in most cases episodic. Disabling attacks lasting 4-72 hours are characterized by moderate or severe headache, usually accompanied by nausea, vomiting and/or photophobia and phonophobia, and sometimes preceded by a short-lasting aura of unilateral fully-reversible visual, sensory or other central nervous system symptoms. In a small minority of cases headache, but not necessarily the associated symptoms, becomes very frequent, with loss of episodicity. Exclusions: Headache, not elsewhere classified (BlockL2‑MB4)

8A80.0 Migraine without aura Recurrent headache disorder manifesting in attacks lasting 4–72 hours. The duration of attacks may be shorter in children. Typical characteristics of the headache are unilateral location, pulsating quality, moderate or severe intensity, aggravation by routine physical activity and headache is associated with nausea and/or photophobia and phonophobia.

8A80.1 Migraine with aura Recurrent attacks, lasting minutes, of unilateral fully-reversible visual, sensory or other central nervous system symptoms that usually develop gradually and are usually followed by headache and associated migraine symptoms. 8A80.10 Hemiplegic migraine Migraine with aura including motor weakness.

8A80.1Y Other specified migraine with aura

8A80.1Z Migraine with aura, unspecified

8A80.2 Chronic migraine Headache occurring on 15 or more days per month for more than three months, which, on at least 8 days per month, has the features of migraine headache and is not associated with medication overuse.

8A80.3 Complications related to migraine 8A80.30 Status migrainosus A debilitating migraine attack lasting for more than 72 hours

8A80.3Y Other specified complications related to migraine 8A80.4 Cyclic vomiting syndrome Recurrent episodic attacks, usually stereotypical in the individual patient, of vomiting and intense nausea. Attacks are associated with pallor and lethargy. There is complete resolution of symptoms between attacks.

8A80.Y Other specified migraine

8A80.Z Migraine, unspecified 8A81 Tension-type headache A primary and highly prevalent headache disorder, in most cases episodic. Attacks of highly variable frequency and duration are characterized by mild-to-moderate headache without associated symptoms, although pericranial tenderness may be present. In a minority of cases the disorder evolves, with increasingly frequent headache and sometimes loss of episodicity. Exclusions: New daily-persistent headache (8A83)

8A81.0 Infrequent episodic tension-type headache Infrequent episodes of headache, typically bilateral, pressing or tightening in quality and of mild to moderate intensity, lasting minutes to days. The pain does not worsen with routine physical activity and is not associated with nausea, but photophobia or phonophobia may be present.

8A81.1 Frequent episodic tension-type headache Frequent episodes of headache, typically bilateral, pressing or tightening in quality and of mild to moderate intensity, lasting minutes to days. The pain does not worsen with routine physical activity and is not associated with nausea, but photophobia or phonophobia may be present.

8A81.2 Chronic tension-type headache A disorder evolving from frequent episodic tension-type headache, with daily or very frequent episodes of headache, typically bilateral, pressing or tightening in quality and of mild to moderate intensity, lasting hours to days, or unremitting. The pain does not worsen with routine physical activity, but may be associated with mild nausea, photophobia or phonophobia.

8A81.Y Other specified tension-type headache 8A81.Z Tension-type headache, unspecified

8A82 Trigeminal autonomic cephalalgias A group of related primary headache disorders essentially characterized by unilateral headache and trigeminal autonomic activation. In most but not all of these disorders, the headache is short-lasting and very frequently recurring, but sometimes remitting for long periods.

8A83 Other primary headache disorder A group of clinically heterogeneous headache disorders, believed to be primary. Although largely unrelated, they fall into four categories: headaches associated with physical exertion; headaches attributed to direct physical but innocuous stimuli; epicranial headaches; and other miscellaneous primary headache disorders.

8A84 Secondary headache Chronic secondary headache is defined as headache that has underlying causes occurring on at least 50% of the days during at least 3 months The duration of pain per day is at least 4 hours (untreated) or several shorter attacks per day occur. Note: Code also the underlying condition

8A84.0 Acute headache attributed to traumatic injury to the head Headache of less than three months’ duration caused by traumatic injury to the head.

8A84.1 Persistent headache attributed to traumatic injury to the head Headache of greater than three months’ duration caused by traumatic injury to the head.

8A84.Y Other specified secondary headache Note: Code also the underlying condition

8A84.Z Secondary headache, unspecified Note: Code also the underlying condition

8A85 Painful cranial neuropathies or other facial pains A group of disorders characterized by head and/or facial pain, presenting variably as a neuralgia or as pain of neuropathic or central origin. Coded Elsewhere: Trigeminal neuralgia (8B82.0) Burning mouth syndrome (DA0F.0)

8A8Y Other specified headache disorders 8A8Z Headache disorders, unspecified 8B82 Disorders of trigeminal nerve The trigeminal nerve is a mixed nerve with three divisions, ophthalmic, maxillary and mandibular divisions, that provides sensory innervation to the face and mucous membrane of the oral and nasal cavities and motor innervations to the muscle of mastication, tensor tympani, tensor veli palatine, mylohyoid and anterior belly of the digastric muscle. The trigeminal nuclear complex extends throughout the brainstem, hence it is susceptible to many pathologic processes including demyelination, ischemia, hemorrhage, infectious and non-infectious inflammation and neoplasm leading to symptoms of trigeminal nerve involvement. Compression of the sensory nerve root outside the brain stem by a vascular loop leads to trigeminal neuralgia. Symptoms and signs depend on the site of the lesion. In general, a trigeminal nerve disorder is associated with hemisensory facial loss, deviation of the jaw to paralyzed side on opening of the mouth, and loss of the corneal reflex.

8B82.0 Trigeminal neuralgia Trigeminal neuralgia is a manifestation of orofacial neuropathic pain restricted to one or more divisions of the trigeminal nerve. The pain is recurrent, abrupt in onset and termination, triggered by innocuous stimuli and typically compared to an electric shock or described as shooting or stabbing. Some patients experience continuous pain between these painful paroxysms.

8B82.1 Atypical facial pain This is a chronic pain of the face, which does not meet other diagnostic criteria.

8B82.Z Disorders of trigeminal nerve, unspecified