EMPYEMA
الدكتور خلدون ذنون- كلية طب نينوى -المرحلة الرابعةObjectives
Pay attention to the following:
1. Definition: pus in the pleural space
2. Bacterial pneumonia is the main cause.
3. Sequelae: bronchopleural fistula and chest wall sinus if untreated.
4. Features: fever, toxicity and physical signs of pleural effusion.
5. Diagnosis needs chest X-ray and wide bore needle aspiration.
6. Treatment: chest tube drainage and long course of antibiotics,
occasionally decortication is needed.
7. TB may cause empyema.
Criteria
Pus in the pleural space.Thin serous fluid or thick, difficult to aspirate.
Microscopy: high neutrophil count.
Whole pleural surfaces involved or loculated-encysted.
Almost unilateral.
Aetiology
Bacterial pneumonias: 40% develop pleural effusion &15%
of them are secondarily infected.
TB
Infection of haemothorax.
Rupture of subphrenic abscess.
Pathology
Both layers of pleura are covered by thick inflammatory exudate.If not treated pus may rupture in to a bronchus causing
bronchopleural fistula, pyopneumothorax or form
subcutaneous abscess & sinus through the chest wall
(empyema necessitans).
Clinical features
Suspect empyema if there is chest infection associated with severe pleuritic chest pain and fever persists or recurs despite use of antibiotics.Unrecognized pulmonary infection may present for the first time as empyema.
High remittent fever, rigor, sweating, malaise & weight loss.
Pleural pain, breathlessness, cough & sputum of underlying lung disease, copious purulent sputum if empyema ruptures in to bronchus (bronchopleural fistula).
Clinical signs of fluid in pleural space.
Investigations
Chest x-ray simulate pleural effusion; air-fluid level is present in pyopneumothorax.
Ultrasonography & CT scan: define extent of pleural thickening &site of fluid, also CT assess underlying lung parenchyma & patency of major bronchi.
Aspiration of pus using wide bore needle under U/S & CT guidance.
Pleural biopsy, histology & culture and nucleic acid amplification test (NAAT) may be needed to differentiate between bacterial & tuberculous empyema.
Biochemical analysis of fluid: glucose < 3.3mmol/L, LDH> 1000U/L, PH<7.
Blood examination: neutrophil leukocytosis, elevated C-reactive
protein.
Management
Thin pus aspirate is managed by wide-bore intercostal tube inserted under U/S or CT guidance connected to a water-seal drain system.If initial aspirate reveals turbid fluid or frank pus or loculation seen on U/S, the tube should be put on 5-10 cm water suction & flushed regularly with 20 ml normal saline.
Antibiotics for 2-4 weeks using C&S. Empirical antibiotics: i.v co-amoxiclav, or cefuroxime with metronidazole
Surgery: If the tube is not providing adequate drainage e.g thick pus, loculated pus; empyema cavity is cleared of pus & adhesions &a wide bore tube is inserted.
Decortication of the lung: if gross thickening of visceral pleura
preventing re-expansion of the lung.
Surgery is also needed if there is bronchpleural fistula.