Disorders of autonomic nervous system (G90) ICD-10-CM
The G90 code range covers disorders of autonomic nervous system with 27 ICD-10-CM diagnosis codes. 21 of them are billable and valid for claim submission in fiscal year 2026, and the category headers group them but cannot themselves be billed.
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.
- dysfunction of the autonomic nervous system due to alcohol G31.2
Codes in the G90 Range 27 codes · 21 billable
- G90 Disorders of autonomic nervous systemNon-billable
- G90.0 Idiopathic peripheral autonomic neuropathyNon-billable
- G90.01 Carotid sinus syncope
- G90.09 Other idiopathic peripheral autonomic neuropathy
- G90.1 Familial dysautonomia [Riley-Day]
- G90.2 Horner's syndrome
- G90.3 Multi-system degeneration of the autonomic nervous system
- G90.4 Autonomic dysreflexia
- G90.5 Complex regional pain syndrome I (CRPS I)Non-billable
- G90.50 Complex regional pain syndrome I, unspecified
- G90.51 Complex regional pain syndrome I of upper limbNon-billable
- G90.511 Complex regional pain syndrome I of right upper limb
- G90.512 Complex regional pain syndrome I of left upper limb
- G90.513 Complex regional pain syndrome I of upper limb, bilateral
- G90.519 Complex regional pain syndrome I of unspecified upper limb
- G90.52 Complex regional pain syndrome I of lower limbNon-billable
- G90.521 Complex regional pain syndrome I of right lower limb
- G90.522 Complex regional pain syndrome I of left lower limb
- G90.523 Complex regional pain syndrome I of lower limb, bilateral
- G90.529 Complex regional pain syndrome I of unspecified lower limb
- G90.59 Complex regional pain syndrome I of other specified site
- G90.8 Other disorders of autonomic nervous systemNon-billable
- G90.81 Serotonin syndrome
- G90.89 Other disorders of autonomic nervous system
- G90.9 Disorder of the autonomic nervous system, unspecified
- G90.A Postural orthostatic tachycardia syndrome [POTS]
- G90.B LMNB1-related autosomal dominant leukodystrophy
Clinical Terms in This Code Range
Definitions from the National Library of Medicine for conditions coded in the G90 range.
Autonomic Dysreflexia
A syndrome associated with damage to the spinal cord above the mid thoracic level (see SPINAL CORD INJURIES) characterized by a marked increase in the sympathetic response to minor stimuli such as bladder or rectal distention. Manifestations include HYPERTENSION; TACHYCARDIA (or reflex bradycardia); FEVER; FLUSHING; and HYPERHIDROSIS. Extreme hypertension may be associated with a STROKE. (From Adams et al., Principles of Neurology, 6th ed, pp538 and 1232; J Spinal Cord Med 1997;20(3):355-60)
Horner Syndrome
A syndrome associated with defective sympathetic innervation to one side of the face, including the eye. Clinical features include MIOSIS; mild BLEPHAROPTOSIS; and hemifacial ANHIDROSIS (decreased sweating)(see HYPOHIDROSIS). Lesions of the BRAIN STEM; cervical SPINAL CORD; first thoracic nerve root; apex of the LUNG; CAROTID ARTERY; CAVERNOUS SINUS; and apex of the ORBIT may cause this condition. (From Miller et al., Clinical Neuro-Ophthalmology, 4th ed, pp500-11)
Hypohidrosis
Abnormally diminished or absent perspiration. Both generalized and segmented (reduced or absent sweating in circumscribed locations) forms of the disease are usually associated with other underlying conditions.
Multiple System Atrophy
A syndrome complex composed of three conditions which represent clinical variants of the same disease process: STRIATONIGRAL DEGENERATION; SHY-DRAGER SYNDROME; and the sporadic form of OLIVOPONTOCEREBELLAR ATROPHIES. Clinical features include autonomic, cerebellar, and basal ganglia dysfunction. Pathologic examination reveals atrophy of the basal ganglia, cerebellum, pons, and medulla, with prominent loss of autonomic neurons in the brain stem and spinal cord. (From Adams et al., Principles of Neurology, 6th ed, p1076; Baillieres Clin Neurol 1997 Apr;6(1):187-204; Med Clin North Am 1999 Mar;83(2):381-92)
Orthostatic Intolerance
Symptoms of cerebral hypoperfusion or autonomic overaction which develop while the subject is standing, but are relieved on recumbency. Types of this include NEUROCARDIOGENIC SYNCOPE; POSTURAL ORTHOSTATIC TACHYCARDIA SYNDROME; and neurogenic ORTHOSTATIC HYPOTENSION. (From Noseworthy, JH., Neurological Therapeutics Principles and Practice, 2007, p2575-2576)
Postural Orthostatic Tachycardia Syndrome
A syndrome of ORTHOSTATIC INTOLERANCE combined with excessive upright TACHYCARDIA, and usually without associated ORTHOSTATIC HYPOTENSION. All variants have in common an excessively reduced venous return to the heart (central HYPOVOLEMIA) while upright.
Pure Autonomic Failure
A degenerative disease of the AUTONOMIC NERVOUS SYSTEM that is characterized by idiopathic ORTHOSTATIC HYPOTENSION and a greatly reduced level of CATECHOLAMINES. No other neurological deficits are present.
Serotonin Syndrome
An adverse drug interaction characterized by altered mental status, autonomic dysfunction, and neuromuscular abnormalities. It is most frequently caused by use of both serotonin reuptake inhibitors and monoamine oxidase inhibitors, leading to excess serotonin availability in the CNS at the serotonin 1A receptor.
About the G90 Code Range
The ICD-10 codes in the G90 section classify various disorders of the autonomic nervous system, which impact the body's automatic functions like blood pressure, heart rate, and sweating. These codes include specific conditions such as hereditary diseases, idiopathic neuropathies, and pain syndromes.
This section includes codes for idiopathic peripheral autonomic neuropathy (G90.0), carotid sinus syncope (G90.01)—also known as carotidynia or carotid sinus hypersensitivity—and familial dysautonomia or Riley-Day syndrome (G90.1). It covers conditions like Horner's syndrome (G90.2), which involves drooping eyelid and pupil changes, and multi-system degeneration of the autonomic nervous system (G90.3), linked to disorders such as Parkinson's disease and multiple system atrophy. The codes also include autonomic dysreflexia (G90.4), and complex regional pain syndrome type I affecting limbs (G90.5 series), with synonyms like sympathetically independent pain. Other codes capture serotonin syndrome (G90.81), various unspecified or autoimmune autonomic neuropathies (G90.89–G90.9), and postural orthostatic tachycardia syndrome (POTS) (G90.A), a disorder causing heart rate and blood flow abnormalities upon standing. This categorization assists coders and healthcare providers in accurately identifying and documenting autonomic nervous system dysfunctions for diagnosis and treatment.
Questions About This Page
How many billable codes are in the G90 range?
Of the 27 codes in this range, 21 are billable and valid for claim submission from October 1, 2025 through September 30, 2026. Category header codes group them but cannot be reported on claims.
What does the G90 range classify?
The range classifies disorders of autonomic nervous system. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2026 ICD-10-CM Tabular List and order file, effective October 1, 2025 through September 30, 2026.
