Coding Infectious Diseases differences between ICD-9 and ICD-10
The first chapter of the new ICD-10-CM codes is infectious and parasitic diseases and you will find some coding infectious diseases are different from the ICD-9-CM code manual. In ICD-10-CM, infections that present with specific manifestations such as meningitis, bronchitis and pyogenic arthritis are found in the body system chapters and are reported with codes that have both the manifestation and the infectious organism.
The very first disease listed in the ICD-9-CM Manual is cholera.There is not much of a change in the coding pattern for Cholera in ICD-10-CM just the new system code numbers. There are three codes under Cholera:
- Cholera due to Vibrio cholerae 01, biovar cholera A00.0
- Cholera due to Vibrio cholerae 01, biovar eltor A00.1
- Cholera, unspecified A00.9
There are many infectious diseases and not all are as easy to translate from ICD-9-CM to ICD-10-CM. For example Tuberculosis, under ICD-9-CM, a fifth character was used to identify TB. ICD-10-CM does not need that information. In addition, while TB is divided by location or affected organ in both ICD-9-CM and ICD-10-CM, the categories are different and they include different subcategories.
There are a total of six possible for Tuberculosis of the eye under ICD-10-CM:
- A18.50, Tuberculosis of eye, unspecified
- 51, Tuberculous episcleritis
- 52, Tuberculous keratitis
- 53, Tuberculous chorioretinitis
- 54, Tuberculous iridocyclitis
- 59, Other tuberculosis of eye
Histoplasmosis is an infection that occurs from breathing in the spores of the fungus Histoplasma capsulatum. It is also known as caver?s disease and spelunker?s lung.
ICD-10-CM includes seven codes:
- 0, acute pulmonary histoplasmosis capsulati
- 1, chronic pulmonary histoplasmosis capsulati
- 2, pulmonary histoplasmosis capsulati, unspecified
- 3, disseminated histoplasmosis capsulati
- 4, histoplasmosis capsulati, unspecified
- 5, histoplasmosis duboisii
- 9, histoplasmosis, unspecified
In ICD-10-CM, any associated manifestations are coded by using an additional code. There is no need in adding a fifth character for associated manifestations in ICD-10-CM .
Reviewing the coding guidelines is very important in ICD-10, while reviewing the new codes for infectious and parasitic diseases. Not all the guidelines remain the same. The guidelines for Methicillin-resistant Staphylococcus aureus are similar, just with different codes, but the guidelines for sepsis are different.
Acute bronchitis due to respiratory syncytial virus, or RSV is reported with a combination code – J20.5.
J20.5 code indicates both the site and manifestation as acute bronchitis and the infectious organism RSV. In ICD-9-CM the case was different.
Acute bronchitis required two codes in ICD-9-CM :
- One for acute bronchitis from the body system chapter
- Second for the infectious agent RSV from Chapter 1.
There are three coding possibilities with meningitis however,
- Code B37.5 Candidal meningitis indicates both the infectious organism and the site and manifestation of the infection.
- Code G00.0 hemophilus meningitis, in the body system indicates the site and manifestation and the infectious organism.
- Code A80.0 acute paralytic poliomyelitis, vaccine-associated, and G02 meningitis in other infectious and parasitic diseases classified elsewhere are two separate codes, one from the infectious disease chapter that is sequenced first and a second from the nervous system chapter that is reported additionally.
Another important section in the ICD-10-CM is coding for bacteremia , septicemia, sepsis, systemic inflammatory response syndrome (SIRS), severe sepsis and septic shock. It is important to understand the medical terms and coding guidelines related to these conditions.
Bacteremia
Bacteremia is the presence of bacteria in the blood and is an abnormal laboratory finding. The healthcare provider should be queried for clarification, if sepsis symptoms are present .The coding should be based on the physician?s documentation and not based on laboratory or radiology findings.
Septicemia
The updated terminology includes ?sepsis? and ?systemic inflammatory response syndrome,? and this practice is same in ICD-10-CM. There is only a single reference to septicemia in ICD-10-CM, and this is found under the code for sepsis, unspecified organism, A41.9. The ICD-10-CM Official Guidelines for Coding and Reporting does not have all references to septicemia.
Systemic Inflammatory Response Syndrome (SIRS)
The idea behind defining SIRS was to create a clinical response to a nonspecific condition of either infectious or noninfectious origin.
There are two codes for SIRS of a non-infectious origin in ICD-10-CM, depending on the presence or absence of associated organ dysfunction:
- 10, systemic inflammatory response syndrome (SIRS) of non-infectious origin without acute organ dysfunction and
- 11, systemic inflammatory response syndrome (SIRS) of non-infectious origin with acute organ dysfunction.
There is no longer a code for SIRS occurring due to an infectious process. The only reference to SIRS in the ICD-10-CM Official Guidelines for Coding and Reporting are those which are related to SIRS due to a non-infectious process. The instructional notes in ICD-10-CM help to code the underlying condition to be sequenced before the SIRS code from subcategory 65.1. One of the most significant classification changes related to sepsis documentation in ICD-10 is in the SIRS category of codes.
Sepsis
Sepsis can be defined as the presence of both an infection and a systemic inflammatory response. In the ICD-10-CM world, in order to accurately reflect the severity of illness , SIRS and sepsis, the provider must document sepsis as a diagnosis. A localized infection with clinical documentation of SIRS only can be coded and reported as the localized infection. The biggest change in ICD-10-CM is that sepsis if not documented as severe will require the code for the sepsis. There will not be an underlying code to indicate SIRS (Systemic Inflammatory Response Syndrome). It would be code A41.9 if the organism is unknown or the appropriate code from A41.x if the organism is known.
Severe sepsis or sepsis with an organ dysfunction will require 2 codes:
- A code from category A41.x and a code from category R65.2x and a code for the organ dysfunction, if known.
- There is no code for multi-organ dysfunction ? each one must be coded individually.
- In ICD-9, sepsis could be used if the document mentioned ?SIRS due to infection.? In ICD-10-CM, it has changed and requires the physician to actually document the word sepsis. Documentation of ?SIRS due to infection? will only code to the infection in ICD-10. Sepsis, severe sepsis, or septic shock should be mentioned to be coded.
Severe Sepsis
When a patient has sepsis with evidence of organ dysfunction, this is known as severe sepsis.
It is classified in ICD-10-CM:
- Code R65.20, severe sepsis without septic shock, or R65.21, severe sepsis with septic shock.
- According to the ICD-10-CM Official Guidelines for Coding and Reporting, an acute organ dysfunction must be associated with the sepsis in order to assign the severe sepsis code. If the clinical documentation does not state the relation of acute organ dysfunction to the sepsis or another medical condition, the provider must be queried for clarification.
- The coding of severe sepsis requires a minimum of two codes.
- The first code will identify the underlying systemic infection, followed by a code from subcategory R65.2, severe sepsis.
- The codes for severe sepsis from subcategory R65.2 should not be assigned as a principal diagnosis.
- Any associated organ dysfunction can be added as an additional code.
Remember, correct coding of infectious diseases in ICD-10-CM requires careful review of the guidelines, alphabetic index and all instructions in the tabular list.