Infectious Disease Compendium

Empyema

Diagnosis

Infection of the pleural space; make the diagnosis on the basis of the parameters of the tap of the pleural fluid. Lots of PMN's, bacteria on gram stain, pH < 7.2 (if in the 6 range think esophageal rupture), glucose level < 40 mg/dl, and lactic dehydrogenase > 1000 IU/liter. From 2007 review: PubMed

Plural Fluid

Uncomplicated Complicated Empyema
Appearance slightly turbid cloudy pus
Ph >7.3 <7.2 na
Glucose >60 <40 na
Glucose ratio pleural/serum >0.5 <0.5 na
LDH <700 >1000 na
PMN count <15,000 >25,000 na
Culture negative occ positive usually positive

These often occur on a spectrum, and the closer it is to pus, the more loculation, the more you should push to drainage.

Epidemiologic Risks

Pneumonia, esophageal rupture, trauma.

Microbiology

Anything (PubMed).

- Community-acquired infections: 50% are Streptococci, and 20% have anaerobes.

- Hospital-acquired:methicillin-resistant Staphylococcus aureus, 25%; Enterobacteriaceae, 18%; Pseudomonas spp. 5%, Enterococcus 12%. Mortality: hospital-acquired infection 47% vrs community 17% and gram-negative 45%, S. aureus 44%, or mixed aerobic infections 46%, vrs streptococcal infection 17% and anaerobes bacteria 20%. Staphylococcus aureus, Streptococcus pneumoniae, Streptococci of all kinds, esp S. milleri, anaerobes, are all high on the list; gram negative rods after trauma.

If you find Candida, think esophageal perforation.

Most common form of extra-pulmonary tuberculosis. The adenosine deaminase is useful in making the diagnosis (PubMed).

Empiric Therapy

Depends on what you suspect and the gram stain. Usually a (third generation cephalosporins PLUS metronidazole) OR (quinolone PLUS metronidazole OR clindamycin) OR carbapenems alone OR penicillin/beta-lactamase inhibitors alone. Duration of therapy is longer rather than shorter; it is until the patient is cured. What a concept.

Pearls

Drain it. Sooner rather than later. Never let the sun set on an empyema unless, of course, you live at the poles. Video Assisted Thoracic Surgery (VATS) has a better outcome than regular chest tubes for large complex empyemas.

Culture positive empyema's do worse clinically by most parameters (PubMed).

Rants

In the middle ages they did not take prisoners on the battlefield. There was someone whose job it was to slit the throats of the enemy wounded (barbers became surgeons, these folks became agents). That is the role of antibiotics in empyema: You win or lose based on the drainage.

ICD9 Codes (Soon to be supplanted by ICD10)

Empyema 510.9.