Pleural effusion is relatively less frequent in children; almost all cases are seen beyond 5 years of age.
Tuberculosis is responsible for majority of the cases followed by pyogenic infection (empyema) and, in a small proportion, thoracic lymphoreticular malignancy.
pleural effusion results from discharge of the caseous material of a peripheral (sub pleural) primary focus or enlarged regional lymph node. Hematogenous, or local spread as also allergic reaction to tuberculous proteins too can cause pleural effusion.
Onset is usually subacute with such manifestations as high fever, cough, chest pain on affected side that worsens on deep breathing and coughing, reflex abdominal pain in case of basal effusion and weight loss.
physical examination reveals decreased chest movements on affected side, mediastinal shift to the opposite side, fullness of the intercostal spaces, decreased vocal fermitus, remarkably dull percussion note, pleural rub, decreased vocal resonance, and decreased breath sounds, Above the effusion level, egophony ( marked hyper-resonance due to compensatory emphysema) may be elicited. percussion note in axilla may be a higher level. This is what is termed as Ellis curve.
X-ray chest shows a uniform opacity with a curved fluid line which may become horizontal when air is also coexisting. There is a definite mediastinal shit to the opposite side.
Aspiration of fluid by a pleural tap confirms the diagnosis. straw-colored fluid with mostly lymphocytuic response strongly favors tuberculous pathology.
Specific chemotherapy depends on the etiology of pleural effusion.therapeutic thoracocentesis is indicated in case of large pleural effusion causing respiratory distress.