PARAPNEUMONIC EMPYEMA Uncomplicated effusion. Thoracic empyema.

Uncomplicated Effusion Nonpurulent. Negative Gram’s stain result, negative culture. Free flowing, pH 7.3, normal glucose level, LDH less than 1000 IU/L. Most resolve with appropriate antibiotics treatment and resolution of the pulmonary infection.

Thoracic Empyema Bacteria invade the normally sterile pleural space. Three stage Table 58-1

Thoracic Empyema-- Stage 1 Exudative effusion. Increase permeability of the inflammatory and swollen pleural surface. Correspond to the uncomplicated parapneumonic effusion. Sterile, fibrin and PMN may present.

Thoracic Empyema-- Stage 2 Fibropurulent, true empyema, complicated pleural effusion. Initial-- fluid is clear : WBC greater than 500 cell/μL, gravity greater than 1.08, protein level greater than 2.5 g/dL, ph less 7.2, LDH reach 1000 IU/L, fibrin deposit. Angioblastic and fibroblastic proliferation, heavy fibrin deposition on both pleura, particularly the parietal pleura. Later– fluid purulent, WBC 15000, ph less 7.0, glucose less than 50 mg/dL, LDH greater 1000 IU/L.

Thoracic Empyema-- Stage 3 1 week after infection-- collagen organization, entrapment the underlying lung. 3-4 week-- mature, turned peel. Chronic-- dense fibrosis contraction and trapping the lung, atelectasis and prolonged pulmonary infection, reduction the size of hemithorax. Fibrothorax-- invasion the chest wall and narrow the intercostals space-- As the end stage of the process.

Complication of Empyema Early or late. Necrosis of visceral pleura. Bronchopleural fistula. Necrosis parietal pleura and chest wall. Osteomyelitis of rib or spine. Esophageal fistula. Metastatic spread （ brain abscess ）.

BACTERIOLOGY Before antibiotics （ 1941 ）, 10% pf pneumonia develop the empyema, the streptoccus and pneumococcus were most frequently. After antibiotics, the empyema decrease as mortality. Staphylococcus became the most prevalent. Recently, the penicillin-resistant staphylococcus, gram’s –negative, anaerobic been predominant microbes.

BACTERIOLOGY Predominant aerobic-- Streptococcus pneumonia, Staphylococcus aureus, E. coli, Klebsiella pneumoniae, Hoemophilus influenzae. Predominat anaerobic-- Anaerobic cocci, pigmented prevotella, porphyromonas, bacteroid fragilis, fusobacterium spp.

BACTERIOLOGY Older children-- Most commonly caused by pneumococcus. Child-- 40% empyema caused by S. pneumoniae, 15% were penicillin-resistant, 44% negative culture （ pretreatment with antibiotics in community setting ）.

BACTERIOLOGY S. pneumoniae responsible for 60%-75% community acquired pneumonia, only 2% develop empyema. S. aures account 1-2% community-acquired pneumonia, 10% adult and 50% children develop empyema. In hospital, the staphylococcus and gram’negative are most common.

CLINICAL FEATURE Shortness of breath, cough, chest pain-- common to pneumonia. Febrile respiratory illness, accentuation, prolongation the symptoms in pneumonia-- alert the possibility of empyema. Aerobic empyema-- acute febrile illness. Anaerobic empyema-- more indolent, usually 10 days.

DIAGNOSIS Chest x-ray—The posterior lateral diaphragmatic angle-- The most dependent position-- Most empyema are found. (Inverted D or pregnant lady sign). Sonography– guide thoracocentesis. Fluid analysis. Aerobic pus-- little odor. Anaerobic-- foul smelling.

Differential diagnosis Lung abscess. Bronchopleural fistula. Lung abscess-- air-fluid level in both PA and lateral view. Empyema-- air-fluid level rare in same in these view.

MAMAGEMENT Effective management require: 1) Control infection and sepsis by antibiotics. 2) Evacuation of pus from pleural space. 3) Obliteration the empyema cavity. ﹡ Delay in drainage increase mortality from 3.4% to 16%.

Antibiotics Therapy Blood, empyema culture, gram stain. Community-acquired--- Third-generation cephalosporin or clindamycin. Gram negative or anaerobes-- third generation cephalosporin and clindamycin. Hospital-acquired-- should guide by culture.

Thoracocentesis 18-gauge needle. Fluid analysis. Chest x ray repeated in 24 hours. Repeated thoracocentesis if volume increased.

Chest tube drainage First step in treatment of acute empyema. Highly effective in treating-- Uncomplicated parapneumonic effusion and classic empyema without loculation. 36 Fr, suction –20 cmH 2 O. Clinical improve in hour. Remove-- drainage less than 50 ml within 24 hour, lung re-expansion. Usually within 5-10 day. Antibiotics should continue 6 week.

Intrapleural fibrinolytic agents Empyema cavity– Composed of fibrin. Fibrolysis agent—Streptokinase and Streptodornase— Significant systemic reaction, unsatisfactory. Purified streptokinase, urokinase– Not allergic– Success rate– 80% for streptokinase （ U/100ml normal saline ）, 90% for urokinase （ U/100ml normal saline ）.

Open drainage Cutting off the chest tube a few centimeter from the skin. Anchoring it with safety pin and tape. Tube may withdrawn a few centimeter each week as the granulation tissue fill the tract.

Video-assisted thoracoscopy （ VATS ） Primary modality for treating complicated empyema after initial therapy. Adhesiolysis and débridement with better exposure and mini-thoracotomy, decortation for lung expansion. Higher successful rate （ 90% ）, shorter hospital stay, less cost. Three-port triangle approach. Morbidity low, chest tube can be removed 3-4 day.

Chronic Empyema. Chronicity– continued infection associated with both fibrosis and bronchopleural fistula. Uncommon. Thoracotomy and decortication Empyemectomy. Thoracoplasty.

EMPYEMA IN CHILDREN Associated with pneumonia. Incidence– Decrease greatly in successful treatment of pneumonia with antibiotics. Past– H. influenzae, β-hemolytic streptococci, S. pneumoniae, anaerobes. Recently– S. pneumoniae, often penicillin resistant is most.

EMPYEMA IN CHILDREN S/S– Fever, cough, dyspnea, tactile and vocal fremitus tachypnea, tachycardia. Goal of therapy– Antibiotics, chest tube drainage, aggressive care. Early thoracotomy– Led early recovery and excellent long-term results. VATS. Open drainage– Not indicated-- because of late skeletal deformities. Enzyme– Not used.