| G90 | Disorders of autonomic nervous system | NON-BILLABLE CODE |
| G90.0 | Idiopathic peripheral autonomic neuropathy | NON-BILLABLE CODE |
| G90.01 | Carotid sinus syncope | BILLABLE CODE |
| G90.09 | Other idiopathic peripheral autonomic neuropathy | BILLABLE CODE |
| G90.1 | Familial dysautonomia [Riley-Day] | BILLABLE CODE |
| G90.2 | Horner's syndrome | BILLABLE CODE |
| G90.3 | Multi-system degeneration of the autonomic nervous system | BILLABLE CODE |
| G90.4 | Autonomic dysreflexia | BILLABLE CODE |
| G90.5 | Complex regional pain syndrome I (CRPS I) | NON-BILLABLE CODE |
| G90.50 | Complex regional pain syndrome I, unspecified | BILLABLE CODE |
| G90.51 | Complex regional pain syndrome I of upper limb | NON-BILLABLE CODE |
| G90.511 | Complex regional pain syndrome I of right upper limb | BILLABLE CODE |
| G90.512 | Complex regional pain syndrome I of left upper limb | BILLABLE CODE |
| G90.513 | Complex regional pain syndrome I of upper limb, bilateral | BILLABLE CODE |
| G90.519 | Complex regional pain syndrome I of unspecified upper limb | BILLABLE CODE |
| G90.52 | Complex regional pain syndrome I of lower limb | NON-BILLABLE CODE |
| G90.521 | Complex regional pain syndrome I of right lower limb | BILLABLE CODE |
| G90.522 | Complex regional pain syndrome I of left lower limb | BILLABLE CODE |
| G90.523 | Complex regional pain syndrome I of lower limb, bilateral | BILLABLE CODE |
| G90.529 | Complex regional pain syndrome I of unspecified lower limb | BILLABLE CODE |
| G90.59 | Complex regional pain syndrome I of other specified site | BILLABLE CODE |
| G90.9 | Disorder of the autonomic nervous system, unspecified | BILLABLE CODE |
| G90.A | Postural orthostatic tachycardia syndrome [POTS] | BILLABLE CODE |
| G90.B | LMNB1-related autosomal dominant leukodystrophy | BILLABLE CODE |
