ICDcodes.org
FY2027

G56.4 vs G90

G56.4 and G90 can never be reported together. ICD-10-CM declares them mutually exclusive with an Excludes1 note, meaning the two conditions cannot occur in the same patient — so exactly one of them is correct for any given encounter.

The official note, declared on G56.4
complex regional pain syndrome I of lower limb (G90.52-)
G56.4

Causalgia of upper limb

Not billable
Chapter 6
Diseases of the nervous system
Section
G50-G59
Use when the record says
  • Complex regional pain syndrome II of upper limb
Indexed under
  • Causalgia (upper limb)
G90

Disorders of autonomic nervous system

Not billable
Chapter 6
Diseases of the nervous system
Section
G89-G99

Excludes1 is not always absolute: where two conditions covered by the note are genuinely unrelated, CMS guidance permits reporting both. Document the reasoning rather than assuming it. More on Excludes1 vs Excludes2 · FY2027