chylous, malignant, and tuberculous effusions (Table 138-1).However, the yield of pleural fluid cultures is low. Transudative pleural effusions have a low specific gravity (<1.015) and protein content (<2.5 g/dL), low lactate dehydrogenase activity (<200 IU/L), and a low white blood cell (WBC) count with few polymorphonuclear cells. In contrast, exudates are characterized by high specific gravity and high protein (>3 g/dL) and lactate dehydrogenase (>250 IU/L) levels. They may also have a low pH (<7.2); low glucose level (<40 mg/dL); and a high WBC count with many lymphocytes or polymorphonuclear leukocytes.
Therapy is directed at the underlying condition causing the effusion and at relief of the mechanical consequences of the fluid collection. For small effusions, especially if they are transudates, no pleural drainage is required. Large effusions that are causing respiratory compromise should be drained. Transudates and most exudates other than parapneumonic effusions can be drained with a chest tube. With parapneumonic effusions/empyema, a chest tube alone is often not sufficient because the fluid may be thick and loculated. In such cases, pleural drainage is best achieved with either the administration of fibrinolytic agents via chest tubes or video-assisted thoracoscopic surgery (VATS). Both fibrinolytic therapy via chest tubes and VATS can reduce morbidity and length of hospital stay, but many patients with small to moderate-sized parapneumonic effusions can be managed conservatively with intravenous antibiotics alone.
Levitzky MG: Pulmonary Physiology, ed 7, New York, 2007, McGraw-Hill
Kliegman RM, Stanton BF, St. Geme JW, et al: Nelson Textbook of Pediatrics, ed 19, Philadelphia, 2011, Saunders
Taussig LN, Landau LI, et al: Pediatric Respiratory Medicine, ed 2, Philadel phia, 2008, Mosby
Wilmott RW, Boat TF, Bush A, et al: Kendig and Chernick’s Disorders of the
Respiratory Tract in Children, ed 8, Philadelphia, 2012, Saunders
The Cardiovascular System
Daniel S. Schneider 19
A maternal history of medication, drug, or alcohol use or excessive smoking may contribute to cardiac and other systemic findings. The prenatal history may reveal a maternal infection early in pregnancy (possibly teratogenic) or later in pregnancy (causing myocarditis or myocardial dysfunction in infants). Infants with heart failure exhibit poor growth, with weight being more significantly affected than height and head circumference.
Heart failure may present with fatigue or diaphoresis with feeds or fussiness. Tachypnea without significant dyspnea may be present. Older children with heart failure may have easy fatigability, shortness of breath on exertion, and sometimes orthopnea. Not keeping up with other children during play or exercise is a sign of exercise intolerance. Heart failure may be misdiagnosed as recurrent pneumonia, bronchitis, wheezing, or asthma.