DxCodebookFY2027 · Oct 1, 2026 – Sep 30, 2027

Category · FY2027

G90 Disorders of autonomic nervous system

  • Header · not billable

G90 is not billable. The category heads 21 billable codes in FY2027, grouped under 10 subdivisions.

Index → code

Where it sits

  1. Chapter 6 Diseases of the nervous system (G00-G99)
  2. G89-G99 Other disorders of the nervous system (G89-G99)
  3. G90 Disorders of autonomic nervous system
Billable codes
21
Subdivisions
10
CC / MCC codes
11 / 0
HCC V28 codes
3
New FY2027
0
Index entries
75

Codes in G90

  1. G90.0
    Idiopathic peripheral autonomic neuropathy
    Header
  2. G90.01
    Carotid sinus syncope
    Billable
    Inclusion terms 1

    Inclusion terms

    • Carotid sinus syndrome
  3. G90.09
    Other idiopathic peripheral autonomic neuropathy
    Billable
    Inclusion terms 1

    Inclusion terms

    • Idiopathic peripheral autonomic neuropathy NOS
  4. G90.1
    Familial dysautonomia [Riley-Day]
    Billable182
  5. G90.2
    Horner's syndrome
    Billable
    Inclusion terms 2

    Inclusion terms

    • Bernard(-Horner) syndrome
    • Cervical sympathetic dystrophy or paralysis
  6. G90.3
    Multi-system degeneration of the autonomic nervous system
    BillableCC199
    Inclusion terms 1, Excludes1 1

    Inclusion terms

    • Neurogenic orthostatic hypotension [Shy-Drager]

    Excludes1

    • orthostatic hypotension NOS (I95.1) I95.1
  7. G90.4
    Autonomic dysreflexia
    Billable
    Use additional code 4

    Use additional code

    • code to identify the cause, such as:
    • fecal impaction (K56.41) K56.41
    • pressure ulcer (pressure area) (L89.-) L89
    • urinary tract infection (N39.0) N39.0
  8. G90.5
    Complex regional pain syndrome I (CRPS I)
    Header
    Inclusion terms 1, Excludes1 4

    Inclusion terms

    • Reflex sympathetic dystrophy

    Excludes1

    • causalgia of lower limb (G57.7-) G57.7
    • causalgia of upper limb (G56.4-) G56.4
    • complex regional pain syndrome II of lower limb (G57.7-) G57.7
    • complex regional pain syndrome II of upper limb (G56.4-) G56.4
  9. G90.50
    Complex regional pain syndrome I, unspecified
    BillableCC
  10. G90.51
    Complex regional pain syndrome I of upper limb
    Header
  11. G90.511
    Complex regional pain syndrome I of right upper limb
    BillableCC
  12. G90.512
    Complex regional pain syndrome I of left upper limb
    BillableCC
  13. G90.513
    Complex regional pain syndrome I of upper limb, bilateral
    BillableCC
  14. G90.519
    Complex regional pain syndrome I of unspecified upper limb
    BillableCC
  15. G90.52
    Complex regional pain syndrome I of lower limb
    Header
  16. G90.521
    Complex regional pain syndrome I of right lower limb
    BillableCC
  17. G90.522
    Complex regional pain syndrome I of left lower limb
    BillableCC
  18. G90.523
    Complex regional pain syndrome I of lower limb, bilateral
    BillableCC
  19. G90.529
    Complex regional pain syndrome I of unspecified lower limb
    BillableCC
  20. G90.59
    Complex regional pain syndrome I of other specified site
    BillableCC
  21. G90.8
    Other disorders of autonomic nervous system
    Header
  22. G90.81
    Serotonin syndrome
    Billable
    Inclusion terms 1, Code first 5, Use additional code 12

    Inclusion terms

    • Serotonin toxicity

    Code first

    • poisoning due to drug or toxin, such as:
    • linezolid (T36.8X- with sixth character 1-4) T36.8X
    • monoamine oxidase inhibitors (T43.1X with sixth character 1-4) T43.1X
    • selective serotonin and norepinephrine reuptake inhibitors [SSNRI] (T43.21 with sixth character 1-4) T43.21
    • selective serotonin reuptake inhibitors [SSRI] (T43.22 with sixth character 1-4) T43.22

    Use additional code

    • code for adverse effect, if applicable, to identify drug, such as:
    • linezolid (T36.8X5) T36.8X5
    • monoamine oxidase inhibitors (T43.1X5) T43.1X5
    • selective serotonin and norepinephrine reuptake inhibitors [SSNRI] (T43.215) T43.215
    • selective serotonin reuptake inhibitors [SSRI] (T43.225) T43.225
    • code, if applicable, to identify:
    • disseminated intravascular coagulation (D65) D65
    • hypertensive crisis (I16.-) I16
    • metabolic acidosis (E87.2-) E87.2
    • shock, not elsewhere classified (R57.-) R57
    • toxic encephalopathy (G92.-) G92
    • ventricular tachycardia (I47.2-) I47.2
  23. G90.89
    Other disorders of autonomic nervous system
    Billable
  24. G90.9
    Disorder of the autonomic nervous system, unspecified
    Billable
  25. G90.A
    Postural orthostatic tachycardia syndrome [POTS]
    Billable
    Inclusion terms 2

    Inclusion terms

    • Chronic orthostatic intolerance
    • Postural tachycardia syndrome
  26. G90.B
    LMNB1-related autosomal dominant leukodystrophy
    Billable200

CC/MCC: as a secondary diagnosis, unless the principal diagnosis is on the code’s PDX exclusion list (MS-DRG v44 Appendix C; list on the code card).

Sources of each column.

Instructions

At G90

Excludes1

  • dysfunction of the autonomic nervous system due to alcohol (G31.2) G31.2

Notes that also apply

Chapter 6 instructions (Excludes2 8): printed on the chapter 6 page.

Index entries

  • Carotid body or sinus syndrome → G90.01
  • Carotidynia → G90.01
  • Faciocephalalgia, autonomic → G90.09
  • Sphenopalatine ganglion neuralgia → G90.09
  • Weiss-Baker syndrome → G90.09
  • Dysautonomia (familial) → G90.1
  • Riley-Day syndrome → G90.1
  • Bernard-Horner syndrome → G90.2
  • Claude Bernard-Horner syndrome → G90.2
  • Horner (-Claude Bernard) syndrome → G90.2
  • Shy-Drager syndrome → G90.3
  • Dysreflexia, autonomic → G90.4
  • Steinbrocker's syndrome → G90.89
  • Sympatheticotonia → G90.89
  • POTS (postural orthostatic tachycardia syndrome) → G90.A
  • Hypersensitive, hypersensitiveness, hypersensitivitycarotid sinus → G90.01
  • Sensitive, sensitivitycarotid sinus → G90.01
  • Syncope (near) (pre-)carotid sinus → G90.01
  • Bradycardia (sinoatrial) (sinus) (vagal)reflex → G90.09
  • Insufficiency, insufficientidiopathic autonomic → G90.09
  • Neuralgia, neuralgic (acute)sphenopalatine (ganglion) → G90.09
  • SyndromeCharcot-Weiss-Baker → G90.09
  • SyndromeHilger's → G90.09
  • SyndromeWeiss-Baker → G90.09
  • Dystrophy, dystrophiacervical sympathetic → G90.2
  • SyndromeHorner's → G90.2
  • Degeneration, degenerativemulti-system → G90.3
  • Hypotension (arterial) (constitutional)neurogenic, orthostatic → G90.3
  • Parkinsonism (idiopathic) (primary)with neurogenic orthostatic hypotension (symptomatic) → G90.3
  • Syndromeserotonin → G90.81
  • Compressionsympathetic nerve NEC → G90.89
  • Imbalanceautonomic → G90.89
  • Imbalancesympathetic → G90.89
  • Irritable, irritabilitysympathetic → G90.89
  • Irritationperipheral autonomic nervous system → G90.89
  • Irritationsympathetic nerve NEC → G90.89
  • Paralysis, paralytic (complete) (incomplete)sympathetic → G90.89
  • Paralysis, paralytic (complete) (incomplete)vasomotor NEC → G90.89
  • Syndromehand-shoulder → G90.89
  • Disease, diseasedsympathetic nervous system → G90.9

35 more, longer entries are not listed; the search box finds them by word.

NCHS Alphabetic Index. Index first, then the Tabular List.

Hierarchy