Pulmonology Coding Alert

Question: We have been unable to find a code for exacerbation of mild, intermittent asthma in the ICD-9-CM manual, and our carrier could not lead us to an appropriate code either. What is the appropriate code to report when a patient presents with mild, intermittent asthma with an exacerbation?

Wisconsin Subscriber

Answer: For the diagnosis of mild, intermittent asthma, most coding experts would consider this to be unspecified, as one cannot discern the etiology nor the duration of the disease from the diagnosis alone.

In this particular instance, unless your physician's documentation offers details that haven't been shared here, you would therefore use this code: 493.92 (Asthma, unspecified; with [acute] exacerbation).

You are right that the ICD-9 manual does not include a specific code for mild, intermittent asthma. Rather, asthma is broadly classified under 493.x with several subclassifications, including the following, among others:

• 493.0x -- Extrinsic asthma

• 493.1x -- Intrinsic asthma

• 493.2x -- Chronic obstructive asthma

• 493.8x -- Other forms of asthma

• 493.9x -- Asthma, unspecified.

The fifth digit should be "0" if the patient has no acute proces and "2" if the patient has acute bronchitis. Codes 493.0x and 493.1x imply the existence of specific etiologies (causes) for the asthma.

Example: Extrinsic asthma is commonly due to allergic reactions and often occurs in children, whereas intrinsic asthma commonly occurs in adults due to reasons other than allergies (for instance, respiratory infections, chemical inhalation, smoke inhalation, etc.).

The definition for code 493.2x implies a prolonged duration of the disease, and 493.8x classifies the remaining types of asthma that are specified, meaning exercised-induced (493.81) and cough variants (493.82).

Finally, 493.9x is for asthma cases that are unspecified.