Altered Mental Status

According to this entry in the Tabular List, what condition can likely be coded with Altered mental status, unspecified as described with the Excludes 1 note:

R41.82 Altered mental status, unspecified

           Change in mental status NOS

Excludes 1:    Altered level of consciousness (R40.-)

                       Altered mental status due to known condition - code to condition

                       Delirium NOS (R41.0)"

According to the entry for R41, the following; 82 Altered mental status, unspecified in the Tabular List, the condition that can likely be coded with this diagnosis is altered mental status when the cause of the change in the mental status is not known or stated. The Excludes 1 note indicates that this code should not be used for:The Excludes 1 note indicates that this code should not be used for:

 Altered level of consciousness (R40. -): This code is used in particular alteration of consciousness where a patient maybe in coma or stupor.

 Altered mental status due to a known condition: When the altered mental status is attributable to a particular disease or disorder, one should code to the specific condition instead of using R41. 82.

 Delirium NOS (R41. 0): In case of presence of delirium without further specification, the code R41 should be assigned. 0 instead.

 Therefore, R41. 81 should be used where there is a change in the patient’s mental state but no particular diagnosis is recorded or where the specific change in the mental status is not described in more detail.