Neurology & Pain Management Coding Alert

Diagnosis codes differ for early vs. late onset of symptoms.

When reporting Alzheimer's disease, keep one thing in mind for guiding your diagnosis choice under ICD-10: the patient's age at the onset of symptoms, not just the severity of symptoms. Prepare now to help your physician document the necessary information to keep your coding on track.

Distinguish the Early and Late Onset of Symptoms

With ICD-9, you have a single diagnosis code -- 331.0 (Alzheimer's disease) -- for Alzheimer's disease. Under ICD-10, however, you'll have three choices based on when the patient's symptoms begin.

• When Alzheimer's sets in before 65 years of age, you report ICD-10 code G30.0 (Alzheimer's disease with early onset).
• On the other hand, if your physician documents the onset of symptoms in a patient who is above 65 years in age, you report ICD-10 code G30.1 (Alzheimer's disease with late onset).

If your physician fails to document the time of onset of symptoms for Alzheimer's disease, you report ICD-10 code G30.9 (Alzheimer's disease, unspecified). The coded descriptor here clearly specifies that the type of Alzheimer's disease (early or late onset) has not been specified. "The ICD codes are not the only differences between ICD-9 and ICD-10," says Marvel Hammer, RN, CPC, CCS-P, PCS, ACS-PM, CHCO, owner of MJH Consulting in Denver, CO. "The listing in the alphabetic index of the codebooks is also different. In the ICD-9 codebook index, you would need to look up the condition under "A" and look for Alzheimer's, whereas in the ICD-10 codebook index, you would need to find the listing for Disease and then locate the listings for Alzheimer's."

Don't Worry About the Severity of Symptoms

Alzheimer's disease can manifest with symptoms of varying severity at any age. In other words, don't assume that early onset is always mild and late onset is always severe. Alzheimer's is a disease of slow onset and the symptoms gradually worsen over a period of years,affecting the patient's memory, thinking, judgment, language, and personality.

When your neurologist documents the patient has Familial Alzheimer's disease (FAD) rather than early or late onset, you would report code G30.8 (Other Alzheimer's disease). This condition is known to be entirely inherited with at least two generations diagnosed. Fifty percent of the offspring will carry the genetic fault and all will go on to develop Alzheimer's, typically with a much earlier onset, in the 40 to 50 age range.

Take note: Symptoms of mild Alzheimer's disease and mild cognitive impairment can overlap. When your physician diagnoses mild cognitive impairment, you should currently report 331.83 (Mild cognitive impairment, so stated). The corresponding ICD-10 code will be G31.84 (Mild cognitive impairment, so stated).

Differentiate Alzheimer's from Cognitive Impairment

Remember that Alzheimer's disease is different from mild cognitive impairment (MCI). "Alzheimer's disease is the most common form of dementia and accounts for 50 -- 80% of all cases," says Hammer. "Dementia usually first appears as forgetfulness. Mild cognitive impairment is the stage between normal forgetfulness due to aging, and the development of AD. People with MCI have mild problems with thinking and memory that do not interfere with everyday activities. They are often aware of the forgetfulness. Not everyone with MCI develops AD."