Lung sounds and clinical manifestations in empyema assessment

Empyema Clinical Manifestation

Empyema: Lung Sounds and other Clinical Manifestations

Over the past decade, empyema has consistently been recognized as an acute, potentially life-threatening respiratory disease. A large number of studies have been conducted over the last years that address the unique symptomatology of empyema and the clinical implications of these symptoms.

The biggest diagnostic challenge of empyema is that patient often present with symptoms very similar and difficult to distinguish from an uncomplicated pneumonia. A patient typically shows symptoms such as fever and chills, excessive sweating, malaise, cough, dyspnea, pleuritic chest pain and unintentional weight loss (Sahn, 2007). These symptoms individually do not warrant a diagnosis of empyema. They do, however, require precautionary follow-up testing that should include a pleural fluid aspiration. The presence of pus -- an opaque, whitish-yellow viscous fluid consisting of serum coagulation proteins, cellular debris and fibrin deposition -- aspirated from the pleural space is a direct indication of empyema and requires immediate drainage. A pleural fluid glucose of less than 40 mg/dL and a lactate dehydrogenase level of less than 1000 IU/L are further indications of empyema and the need to drain the pleural space.

Empyema develops from an untreated pneumonia and represents a continuum from clear fluid with low white cell numbers to the characteristic pus and a high white blood count (Walker, Wheeler, Legg, 2011). This fluid aggregation in the pleural space often causes chest pain and reduced lung sounds. The chest pain worsens when the patient breathes in deeply. Associated signs include absent breath sounds, reduced chest expansion, and dullness to percussion (Clark, 2009). Lung sounds may also be "wet" and present as crackles from the build-up of fluid. A case study of a patient who presented with empyema reveals that patients often present with seemingly innocuous symptoms (Buyers, 2010). An examination showed vital signs -- temperature, pulse, blood pressure and oxygen saturation -- that were not out of normal range or cause for concern. Upon performing chest radiography, however, the attending physician recognized a massive fluid collection in the left hemi-thorax.

Heffner, Klein and Sampson conducted a study that evaluates the diagnostic usefulness of chest imaging for identifying pleural space infections including empyema (2010). The authors found that pleural effusions in ultrasonography typically appear as triangular anechoic collections above the diaphragm. This clinical assessment provides corroborating evidence to the abovementioned symptoms. In children, an even faster diagnostic tool that provides a 96% positive predictive value of the causative agent of empyema is a new Binax NOW Streptococcus pneumoniae Antigen test (Flores, Moro, Berron, Jimenez, & Casal, 2010).

Other studies identify a number of risk factors or secondary non-specific symptoms that are often associated with empyema. In a review of the empyema literature, Froudarakis identifies malignancies such as lung cancer, breast cancer, gastric cancer and lymphoma as contributing factors for pleural disease (2008). According to another study, at least two-third of patients will present with an identifiable risk factor including immunosuppressive states (HIV infection, diabetes mellitus, and malnutrition), alcohol or intravenous drug abuse, poor dental hygiene and gastroesophageal reflux.

References:

1. Walker W, Wheeler R, Legg J. (2011). Update on the causes, investigation and management of empyema in childhood. Archives of Disease in Childhood, 96, 5, 482-488.