Case: An 85 year old male with past history of CVA and GERD is admitted from home for RLL “community acquired” pneumonia (CAP) and treated with Rocephin and Zithromax.

Documentation throughout the record including discharge summary is CAP except ID consult on day 2 with impression “CAP due to aspiration” and Rocephin changed to Zosyn.

What is the principal diagnosis?

Answer: The principal diagnosis should be aspiration pneumonia. A query for clarification is not required even though the diagnosis of “CAP due to aspiration” is documented by a physician other than the attending. Rationale:

  • ICD-9-CM coding guidelines require that codes be assigned to the highest degree of specificity: Aspiration describes a specific type (cause) of pneumonia, CAP does not and is assigned to code 486 (unspecified pneumonia).

    ICD-9-CM Official Conventions state: “[NOS] is equivalent to ‘unspecified’ and should only be used when the coder lacks the information necessary [in the medical record] to code a more specific four-digit subcategory.”

  • “CAP” and “CAP due to aspiration pneumonia are not conflicting diagnosis: The ID consultant wrote a more specific diagnosis than the attending physician, however this diagnosis does not conflict with that written by the attending physician. Aspiration pneumonia may occur in both community-acquired and healthcare-associated circumstances.

    As noted in the Guidelines section of the CDI Pocket Guide, the Official Coding Guidelines states the following:
    “The entire record should be reviewed to determine the specific reason for the encounter and the conditions treated… the term provider is used throughout the guidelines to mean physician or any qualified health care practitioner who is legally accountable for establishing the patient’s diagnosis.”

    Also from Medicare’s MLN SE1121: “The failure of the attending physician to mention a consultant’s diagnosis is not a conflict…. As with all codes, clinical evidence should be present in the medical record to support code assignment.”

  • The diagnosis of “CAP due to aspiration pneumonia” is clinically validated by documentation in the record: Pneumonia is clearly and consistently documented throughout the record with additional clarifying information that it is due to aspiration which is confirmed by several clinical indicators: elderly, history of CVA and GERD, and RLL infiltrate. Antibiotics were specifically changed to provide coverage for anaerobic organisms associated with aspiration (Zosyn). That documentation is taken from any provider (not just the attending) so long as there is no “conflict”.

    Official Coding Guidelines Section I.A.5.b includes: “[Codes] titled ‘unspecified’ are for use when the information in the medical record is insufficient to assign a more specific code.”