F05 vs R41.0
F05 and R41.0 are not coded together. ICD-10-CM declares them mutually exclusive with an Excludes1 note — the two conditions are not expected to occur together, so exactly one of them is normally correct for a given encounter. The Official Guidelines carve out one exception: if the two conditions are clearly unrelated to each other, both may be reported.
Delirium due to known physiological condition
- Chapter 5
- Mental, Behavioral and Neurodevelopmental disorders
- Section
- F01-F09
- Acute or subacute brain syndrome
- Acute or subacute confusional state (nonalcoholic)
- Acute or subacute infective psychosis
- Acute or subacute organic reaction
- Acute or subacute psycho-organic syndrome
- Delirium of mixed etiology
- Delirium superimposed on dementia
- Sundowning
- Sundowning
- Confusion, confused › epileptic
- Delirium, delirious › postprocedural (postoperative)
- Delirium, delirious › puerperal
- Epilepsy, epileptic, epilepsia › twilight
Disorientation, unspecified
- Chapter 18
- Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified
- Section
- R40-R46
- Confusion NOS
- Delirium NOS
- Confusion, confused
- Delirium, delirious (acute or subacute) (not alcohol- or drug-induced)
- Disorientation
- Confusion, confused › acute
- Delirium, delirious › due to › unknown etiology
These two codes sit in different chapters of the Tabular List, which is usually the clearest signal that they describe different underlying processes rather than different degrees of the same one.
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