ICD-10 essentials for busy neurologists who would rather be doing something else: Alzheimer's, migraine, neurologic defects

Chemists can dismiss all human physiology as just chemistry, and physicists might go even further -- all chemistry is just physics. I find all human physiology pretty amazing and fascinating. The fact that we keep taking that next breath, that our heart beats one more time, that we pee at regular intervals -- holy cow, the whole thing is incredible. But I have to confess, I find something extra intriguing and mysterious about the physiology of the brain and its associated wiring -- maybe because one of its byproducts is what we call consciousness, maybe because at 50 my particular flavor of Charcot-Marie-Tooth Syndrome is starting to become interesting. I mean, the world needs proctologists, but neurology is extra cool.

Hopefully I have awakened all the old physician specialty rivalries, and I will get some interesting mail. Meanwhile, let’s talk about ICD-10. There is new stuff and reclassified stuff in ICD-10 for documentation and coding of neurological conditions. There are so many to choose from I feel like a kid in a candy store picking only three, but here are some purported biggies: Alzheimer’s disease, migraine and neurologic deficits following a stroke.

Alzheimer’s disease
ICD-9 only has one code for Alzheimer’s disease. In ICD-10, if you document whether the disease is early onset or late onset, that distinction can be coded. I trust there are generally accepted definitions of this distinction. In addition, the ICD-10 book provides precise instruction for which additional codes to use when there is associated delirium (F05), dementia with behavioral disturbance (F02.81) or dementia without behavioral disturbance (F02.80). The new Alzheimer’s disease codes are listed below.

G30.0 Alzheimer's disease with early onset 
G30.1 Alzheimer's disease with late onset 
G30.8 Other Alzheimer's disease 
G30.9 Alzheimer's disease, unspecified

331.0 Alzheimer's disease    

The new migraine codes in ICD-10 are a simple fleshing-out of the “other migraine” category to include four specific types of migraine: cyclical vomiting, ophthalmoplegic migraine, periodic headache syndromes and abdominal migraine. All the other terminology used is just as it is in ICD-9. Like ICD-9, there are also separate codes for all conditions when documented as intractable. Examples of the not intractable variety are given below.

G43.809 Other migraine, not intractable, without status migrainosus
G43.A0 Cyclical vomiting, not intractable 
G43.B0 Ophthalmoplegic migraine, not intractable 
G43.C0 Periodic headache syndromes in child or adult, not intractable 
G43.D0 Abdominal migraine, not intractable

346.20 Variants of migraine, not elsewhere classified, without mention of intractable migraine without mention of status migrainosus   

Neurologic deficits following a stroke
The terminology and classification of the deficits themselves — hemiplegia, dysphasia, dysphagia and all the rest — have not changed in ICD-10, but two other levels of detail have been added to the codes in this area.

1) If documented, the specific type of cerebrovascular event (e.g., subarachnoid hemorrhage, cerebral infarction, etc.) that preceded the neurologic deficit can be coded. In addition, the use of the term late effect is discontinued, replaced by the more literal and precise term following, as in [neurologic deficit] following [cerebrovascular accident]. The resulting expansion of detail is shown in the dysphasia example below.

I69.021 Dysphasia following nontraumatic subarachnoid hemorrhage 
I69.121 Dysphasia following nontraumatic intracerebral hemorrhage 
I69.221 Dysphasia following other nontraumatic intracranial hemorrhage 
I69.321 Dysphasia following cerebral infarction 
I69.821 Dysphasia following other cerebrovascular disease 
I69.921 Dysphasia following unspecified cerebrovascular disease

438.12 Late effects of cerebrovascular disease, dysphasia

2) Codes for hemiplegia or monoplegia following a CVA have the same expansion of detail above. If documented, the type of CVA that caused the paralysis can be coded. In addition, in ICD-10 you also have the ability to specify whether the affected side is the left or right side. In ICD-9, you can only specify whether the affected side is dominant or non-dominant.

Two new axes of classification applied across an area creates a lot of new codes, so I won’t reproduce the whole chunk of them here but will just show one example of what is available, for coding a patient with “hemiplegia of the non-dominant side following a nontraumatic intracerebral hemorrhage”:

I69.153 Hemiplegia and hemiparesis following nontraumatic intracerebral hemorrhage affecting right non-dominant side 
I69.154 Hemiplegia and hemiparesis following nontraumatic intracerebral hemorrhage affecting left non-dominant side 

438.22 Late effects of cerebrovascular disease, hemiplegia affecting nondominant side 

These are modest improvements, to be sure. I always pick the conditions before I look at the differences between the two code sets so I am not influenced either way by the difference or similarity between ICD-9 and ICD-10. I was frankly hoping for something a little more extra cool to go with my intro.  But let’s face it, codes are not that exciting. They are the CliffsNotes version of our most recent understanding of disease, as processed through the minds of an enormous global committee with its own timelines and traditions. Not exactly a recipe for cool stuff, but it does the job.

Rhonda Butler is a senior clinical research analyst with 3M Health Information Systems. She is responsible for the development and maintenance of the ICD-10 Procedure Coding System since 2003 under contract to CMS, and for the development and maintenance of the ICD-10 General Equivalence Mappings (GEMs) and Reimbursement Mappings under contract to CMS and the CDC.  She leads the 3M test project to convert the MS-DRGs to ICD-10 for CMS, and is on the team to convert 3M APR-DRGs to ICD-10. Rhonda also writes for the 3M Health Information Systems blog.

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