A five-year-old female with profound developmental delays and epilepsy has chronic static encephalopathy secondary to epilepsy and epileptic encephalopathy. In the Alphabetic Index, under the main term Encephalopathy there is no subentry for static. What is the appropriate ICD-10-CM diagnosis code assignment for chronic static encephalopathy secondary to epilepsy and epileptic encephalopathy? Is static encephalopathy inherent to the epilepsy and not coded separately?
Assign code G93.49, Other encephalopathy, for chronic static encephalopathy. Assign also code G40.909 Epilepsy, unspecified, not intractable, without status epilepticus, for the epilepsy. Although the static encephalopathy is linked to the epilepsy, the provider has documented that it is a chronic condition. Unlike transient epileptic encephalopathy occurring in the postictal state, where the patient returns to baseline, static encephalopathy is a chronic or permanent condition and is therefore coded separately.
When encephalopathy is linked to a specific condition, it is appropriate to use the code describing “other encephalopathy,” since codes describing “other” or “other specified” are for use when the information in the medical record provides detail for which a specific code does not exist. This is consistent with advice published in Coding Clinic Second Quarter 2018, pages 24-25.