A 74 year old male with a past medical history of advanced dementia and type 2 diabetes presents via EMS from his long term advanced care facility for cough and shortness of breath. Patient is AOx1 and intermittently follows commands at baseline. EMS reports that the facility nurse noticed that he was hypoxic and had a “nasty cough.” Vitals include Temp 100.6F, HR 110, BP 126/80, RR 22, SpO2 89% on room air. Exam shows a chronically ill, pale appearing older male in mild respiratory distress with a productive cough. Lung sounds are notable for crackles in the lower right lung. A chest x-ray demonstrates focal consolidations of the right middle and right lower lobes with a moderate sized pleural effusion above the right hemidiaphragm. Which of the following laboratory values is NOT part of the diagnostic criteria for an empyema?
A: pleural gram stain of culture
B: pleural LDH
C: pleural pH
D: pleural protein
Answer: pleural protein
This patient is presenting with pneumonia demonstrated by imaging results consistent with the clinical findings of fever, cough, and hypoxia. Pneumonia is the most common cause of an empyema which has specific diagnostic criteria distinct from the Light Criteria for pleural effusions. Approximately 40% of cases have negative cultures. Treatment is drainage and broad spectrum antibiotics with anaerobic coverage.
| Diagnostic Criteria for Empyema | Light Criteria for Exudative Pleural Effusion (requires 1 of the following) |
| Aspiration of grossly purulent fluid plus one of the following: | Pleural protein/serum protein > 0.5 |
| Positive gram stain or culture | Pleural LDH/serum LDH > 0.6 |
| Pleural fluid glucose < 40 | Pleural LDH > 2/3 upper limit of normal serum LDH |
| Pleural pH < 7.2 | |
| Pleural LDH > 1000 |
References:
Mace SE, Anderson E. Lung Empyema and Abscess. In: Tintinalli JE, Ma O, Yealy DM, Meckler GD, Stapczynski J, Cline DM, Thomas SH. eds. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 9e. McGraw Hill; 2020.
Birkenkamp K, O’Horo JC, Kashyap R, et al: Empyema management: a cohort study evaluating antimicrobial therapy. J Infect 72: 537, 2016.
