Q&A: Appropriate coding for the flu

Q: I am never sure of correct sequencing when the admission is for flu, pneumonia, and asthma.

The patient presented in the emergency department (ED) with shortness of breath, still tight after nebulizer treatment in the emergency room. The patient was kept for observation for one day, then was admitted. Documentation includes:

• Influenza and upper respiratory tract infection
• Superimposed RLL community-acquired pneumonia (CAP), per chest x-ray
• Fever 101.8 in ED; respiratory rate (RR) 24; white blood cell count (WBC) 12.6
• Mild persistent asthma in exacerbation due to the above (wheezing, tachycardia in the ED, 130s); acute hypoxic respiratory failure (PO 90%).

Can you suggest proper sequencing and if queries are needed?

A: Per the Official Guidelines for Coding and Reporting only confirmed cases of influenza are coded. No laboratory tests are required, just the diagnostic statement by the provider that the patient has influenza. In ICD-10, there are combination codes that represent both influenza and its manifestations, such as pneumonia. Provider documentation linking the conditions is necessary to use these combination codes, so a query may be needed if the documentation is not present in the chart.

When a patient has both influenza and pneumonia due to the influenza, per coding conventions the influenza will be sequenced first, under code J14 Pneumonia Due To H. Flu. There is a “code first” note for associated influenza, if applicable. The influenza codes will map to different MS-DRGs, depending on the combination code applied.

Another reason for a query when there is documentation of pneumonia would be to identify the etiology of the pneumonia. Based on the documented etiology, the MS-DRG assignment could vary.  If there is a bacterial organism causing the pneumonia, the identification of the organism could move a simple pneumonia to a complex pneumonia. The alphabetic index does not have an entry in ICD-10 for CAP. It is typically simple pneumonia. However, it could also be atypical pneumonia, which does have an entry in the alphabetic index code J18.9 (the default code for pneumonia). If no organism is identified, and only the term “CAP” is documented, it will default to J18.9 pneumonia, unspecified organism.

The specificity required for a diagnosis of asthma would be the frequency, severity, and any complications associated with it such as an exacerbation or status asthmaticus. If any of these elements are missing, query the provider. The documentation of asthma with acute exacerbation or status asthmaticus would give you a “CC,” and if both were present, per Coding Clinic, only the status asthmaticus would be coded.  

You also mentioned acute hypoxic respiratory failure, but I am unsure if this diagnosis is clinically supported, as the question does not include any treatment provided. For accurate code assignment, we need to know if this diagnosis meets the definition of the principal diagnosis. If the acute hypoxic respiratory failure meets the definition of the principal diagnosis, then we would follow the Official Guidelines for Coding and Reporting for selection of the principal diagnosis. There is also Coding Clinic, First Quarter, 2005 which tells us when a patient is admitted with respiratory failure and another acute condition, the principal diagnosis will depend on the circumstances of admission. If both the respiratory failure and the other acute condition are responsible for occasioning the admission to the hospital, then follow the Official Guidelines for Coding and Reporting regarding two or more diagnoses that equally meet the definition for principal diagnosis (Section II, C).

In the scenario as described, I also see that the patient had a fever of 101.8, heart rate in 130’s, respiratory rate 24, and WBC of 12.6 with documentation of an infection, I do not know what the patient received for treatment, but I would look to see if there is possibility that the patient might have been septic on admission and, if so, I would query the provider for sepsis and ask if the acute respiratory failure or pneumonia was related to the sepsis. If the provider agreed that the acute organ dysfunction was related to the sepsis, a code for severe sepsis would also be assigned.

Remember some conditions such as sepsis, obstetrics, HIV, and poisoning have chapter-specific guidelines that give us additional information about sequencing, so they also need to be reviewed.

Editor’s note: Sharme Brodie, RN, CCDS answered this question. Brodie is a CDI education specialist for HCPro in Middleton, Massachusetts. Contact her at sbrodie@hcpro.com. For information regarding CDI Boot Camps offered by HCPro, visit www.hcprobootcamps.com.