Diseases of the nervous system include disorders of the central nervous system that affect the brain and spinal cord, and diseases of the peripheral nervous system. Some examples of disorders of the central nervous system are Parkinson’s disease and cerebral degeneration. Diseases of the peripheral nervous system include polyneuropathy, myasthenia gravis, and muscular dystrophy.
In ICD-10-CM, chapter 6, we no longer see the inclusion of the sense organs-the eye and adnexa, and the ear and mastoid process, as we see now in ICD-9-CM. So while both the nervous system diseases in ICD-9-CM and in ICD-10-CM are still found in chapter 6, the diseases of the eye and adnexa are in chapter 7 in ICD-10-CM. The ear and mastoid process are in chapter 8 in ICD-10-CM.
Since physician documentation is the basis for code selection in both the ICD-9 and ICD-10 code sets, the need for proper documentation has always been important. However, in ICD-10 we see that there is a much greater level of specificity, necessitating the provider’s medical record documentation includes more precise clinical information.
In addition, ICD-10 utilizes more current, updated, and standardized clinical terms. For example, such common terms as “intractable” in the ICD-10 code set covers many other commonly used clinical words. According to an instructional note under category G40, the following terms are to be considered equivalent to intractable: pharmacoresistent (pharmacologically resistant), treatment resistant, refractory (medically), and poorly controlled. Therefore, any one of these terms will code to “intractable.”
In the case of “epilepsy” and “seizure disorder,” which are central nervous system disorders both characterized by sudden-onset seizures and muscle contractions, the seizure disorders and recurrent seizures are coded to epilepsy. However, convulsions, new-onset, and single, febrile or hysterical seizures are coded as non-epileptic.
Additionally, several of the nervous system conditions are manifestation of other diseases; therefore, dual coding is necessary to report both the underlying condition and the manifestation. ICD-10-CM expands the use of combination codes for common etiologies and symptoms or manifestations (e.g. dementia with Parkinsonism).
ICD-10-CM classifies diseases of the nervous system by the type of disease and by the cause of the disease or disorder, such as intraoperative and postprocedural complications or drug-induced. Severity and status of the disease in terms of acute or chronic, in addition to the site, etiology, and any secondary disease process are the components needed within the provider’s documentation.
Next week, in Part 3 of this series, we will cover coding guidelines for ICD-10-CM Chapter 7: Diseases of the Eye and Adnexa.
Part 1 of the series, including tables of the specific sections or blocks of codes in chapters 6-8, also is available for review: Coding for Nervous System Diagnoses – ICD-10-CM Compared to ICD-9-CM – PART 1.
For more ICD-10 articles, please visit our ICD-10 Updates page.
— Compiled by former CIPROMS ICD-10 Coordinator, Angela Hickman, CPC, CEDC, AHIMA-Approved ICD-10 CM/PCS Trainer, AHIMA Ambassador. All rights reserved. For use or reprint in your blog, website, or publication, please contact us at firstname.lastname@example.org.