Infection = A host response to the presence of microorganisms or tissue invasion by microorganisms.
Bacteremia = The presence of viable bacteria in circulating blood.
SIRS (Systemic Inflammatory Response Syndrome) = The systemic inflammatory response to a wide variety of severe clinical insults, manifested by two or more of the following conditions:
- Temperature above 101 F (38.3 C) or below 96.8 F (36 C)
- Heart rate higher than 90 beats a minute
- Respiratory rate higher than 20 breaths a minute or PaCO2 < 32 mm Hg
- WBC count > 12,000/mm3, < 4000/mm3, or > 10% immature (band) forms
Sepsis = The systemic inflammatory response to infection and is defined as the presence of SIRS (Systemic Inflammatory Response Syndrome) in addition to a documented or presumed infection. The clinical manifestations would include two or more of the following conditions as a result of a documented infection.
Severe Sepsis/SIRS = Sepsis (SIRS) associated with organ dysfunction, hypoperfusion, or hypotension. Hypoperfusion and perfusion abnormalities may include, but are not limited to, lactic acidosis, oliguria, or an acute alteration in mental status. Sepsis is usually considered severe when the patient exhibits at least one of the following signs and symptoms (which may indicate an organ may be failing):
- Significantly decreased urine output
- Abrupt change in mental status
- Decrease in platelet count
- Difficulty breathing
- Abnormal heart pumping function
- Abdominal pain
Refractory (Septic) Shock/SIRS Shock = A subset of severe sepsis (SIRS) and defined as sepsis (SIRS) induced hypotension despite adequate fluid resuscitation along with the presence of perfusion abnormalities that may include, but are not limited to, lactic acidosis, oliguria, or an acute alteration in mental status. Patients receiving inotropic or vasopressor agents may no longer be hypotensive by the time they manifest hypoperfusion abnormalities or organ dysfunction, yet they would still be considered to have septic (SIRS) shock.
To be diagnosed with septic shock, the patient will have signs and symptoms of severe sepsis, plus extremely low blood pressure that does not respond to simple fluid replacement.
Multiple Organ Dysfunction Syndrome (MODS) = Presence of altered organ function in an acutely ill patient such that homeostasis cannot be maintained without intervention.
Coding of SIRS
SIRS, Systemic Inflammatory Response Syndrome is found in R65.1-. Note that there is an Excludes1 here for sepsis, which instructs coders to code to the infection. There is also an Excludes1 for “severe sepsis” which is found in R65.2-. Also note that the concept of SIRS is that it is of “noninfectious origin.”
Coding of Sepsis
For a diagnosis of sepsis, assign the appropriate code for the underlying systemic infection. If the type of infection or casual organism is not further specified, assign code A41.9, Sepsis, unspecified organism.
A code from subcategory R65.2, Severe sepsis, should NOT be assigned unless severe sepsis or an associated acute organ dysfunction is documented.
Note that “urosepsis” is a nonspecific term, and is not to be considered synonymous with sepsis.
If sepsis is documented with organ dysfunction or multiple organ dysfunction (MOD), then follow the rules for coding severe sepsis.
Coding of Severe Sepsis
The coding of severe sepsis requires a minimum of 2 codes:
- A code for the underlying systemic infection, followed by
- A code from subcategory 2, Severe sepsis.
If the causal organism is not documented, assign code A41.9, Sepsis, unspecified organism, for the infection. Additional codes for any associated acute organ dysfunction are also required. The term “severe sepsis” includes the following alternative wording:
- Infection with associated acute organ dysfunction
- Sepsis with acute organ dysfunction
- Sepsis with multiple organ dysfunction
- Systemic Inflammatory Response Syndrome (SIRS) due to infectious process with acute organ dysfunction
Sequencing of Severe Sepsis
If severe sepsis is present on admission, and meets the definition of a principal diagnosis, the underlying systemic infection should be assigned as principal diagnosis followed by the appropriate code from subcategory R65.2, as required by the sequencing rules in the Tabular List. A code from subcategory R65.2 can never be assigned as a principal diagnosis.
When severe sepsis develops during an admission (it was not present on admission) the underlying systemic infection and the appropriate code from subcategory R65.2 should be assigned as secondary diagnoses.
Coding of Septic Shock
Septic shock generally refers to circulatory failure associated with severe sepsis, and therefore, it represents a type of acute organ dysfunction. For all cases of septic shock, the code for the underlying systemic infection should be sequenced first, followed by code R65.21, Severe sepsis with septic shock. (Septic shock indicates severe sepsis is also present.) Any additional codes for any other acute organ dysfunction should also be assigned.
For cases of septic shock, the code for the systemic infection should be sequenced first, followed by code R65.21, Severe sepsis with septic shock or code T81.12, Post-procedural septic shock. Any additional codes for any other acute organ dysfunctions should also be assigned. As noted in the Tabular List, the code for septic shock CANNOT be assigned as a principal diagnosis.
Sepsis and Severe Sepsis in Other Infections
Sepsis and Severe Sepsis in a Localized Infection:
If the reason for treatment is both sepsis and severe sepsis and a localized infection such as pneumonia or cellulitis, a code for the underlying systemic infection should be assigned first, and the code for the localized infection should be assigned as a secondary diagnosis. If the patient has severe sepsis, a code from subcategory R65.2 should also be assigned as a secondary diagnosis.
Sepsis Due to a Post-procedural Infection:
The provider’s documentation must link the cause of the infection being due to the procedure. For such cases, the post-procedural infection code, such as T80.2, Infections following infusion, transfusion, and therapeutic injection; T81.4, Infection following a procedure; T88.0, Infection following immunization; or O86.0, Infection of obstetrical surgical wound, should be coded first, followed by the code for the specific infection. If severe sepsis, or septic shock is also present, the appropriate additional code should also be assigned.