Accurate coding is an important function of neurologic practice. This section of Continuum, contributed by members of the AAN Medical Economics and Management Committee, includes a table of helpful coding information related to the issue topic. The table may include diagnosis coding, Evaluation and Management (E/M) coding, procedure coding, or a combination, depending on which is most useful for the subject area of the issue.
Below is a list of International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) (diagnosis) codes useful in the evaluation and management of dementia. This list is not all inclusive, and reference to a full volume of the ICD-9-CM is recommended for helpful subterms, instructions, and coding other conditions that may be causative or affecting the presenting illness. For a full set of rules regarding diagnosis coding, see Official ICD-9-CM Guidelines for Coding and Reporting, which may be found at: www.cdc.gov/nchs/data/icd9/icdguide09.pdf.
ICD-9-CM is an old classification system with updates that attempt to capture current knowledge. Since codes cannot be moved, the primary behavioral dementia description codes remain in the "Mental Disorders" chapter. Fortunately, several of these codes are accompanied by a "Code first" instruction that makes the primary-listed code one also listed elsewhere in ICD-9-CM. As a result, Alzheimer disease requires the listing of two codes: first list 331.0, and then a second from the codes 290.0 to 290.3. Likewise, codes 294.0 to 294.9 are secondary codes requiring a causative condition to be listed first. During the initial evaluation for dementia, before a diagnosis is made, it is permissible to use a symptom code such as 780.93, memory loss.