The clinical distinction between community-acquired pneumonia (CAP), acquired without health care contact, and health care-associated pneumonia (HCAP), acquired outside the hospital but in connection with other health care contact, is crucial for correct management and antibiotic selection. http://www.acphospitalist.org/archives/2011/05/coding1.pdf
CAP is usually caused by Pneumococcus, Chlamydia or Mycoplasma pneumoniae or by viruses, and is typically treated with one or more of the following antibiotics depending on whether the patient is admitted to an ICU: ceftriaxone, azithromycin, doxycycline or a fluoroquinolone (e.g., levofloxacin).
Patients with HCAP are considered high-risk for gram-negative and possibly staphylococcal infection, including MRSA, and they require multiple, broad-spectrum antibiotics such as piperacillin/tazobactam, vancomycin, cefepime, aminoglycosides and others.
When it comes to the coding of pneumonia, the rules do not recognize nosocomial terms like HCAP, which means that this diagnosis will automatically default to a “simple” pneumonia like CAP, even though the patient may be in a critical, life-threatening condition.
To capture the true severity and complexity of HCAP with the correct codes, the physician must document what organisms are probable, likely or suspected as the cause, or that the pneumonia is due to aspiration. Unlike in outpatient coding, any condition documented as probable, likely or suspected will be considered “confirmed” for inpatient coding unless the diagnosis changes prior to discharge.
Since HCAP is very likely to involve gram-negative organisms and/or staphylococcus, it is perfectly appropriate and necessary to mention these as the possible/probable cause when clinical criteria are met and multiple, broad-spectrum antibiotics are prescribed. A positive sputum culture is not required. The terms “coverage” or “coverage for” are not adequate documentation for coding purposes; the suspected organism or organisms must be specifically mentioned.
Also, do not forget that aspiration pneumonia is much more common than generally recognized; this diagnosis should be considered whenever two or more risk factors for aspiration are present.
In summary, in all cases of pneumonia, make the clinical distinction between CAP and HCAP, and select the appropriate antibiotics while awaiting culture results. Whenever the diagnosis is HCAP, be sure to document the suspected organism or organisms based on clinical criteria and your antibiotic selection. Consider aspiration pneumonia especially when two or more risk factors are present and include anaerobic antibiotic coverage.