Korean J Pediatr 2012;55(5):177-180 • http://dx.doi.org/10.3345/kjp.2012.55.5.177 179 ) L m ( d i u l f l a r u e l P Postnatal day Fig. 2. Changes in pleural drainage after OK-432 (picibanil) instillation in case 2. Lt, left; Rt, right. gradually. Right pleural drainage had resolved after three days, and the right chest tube was removed on postnatal day 14. However, the right pleural fluid reaccumulated three days after tube removal. The amount of right pleural fluid drained was 80 to 100 mL/day until postnatal day 25. We performed pleurodesis with OK­432 on the right pleural spaces on postnatal day 26 as a bedside procedure. The amount of pleural fluid drainage promptly decreased after OK­432 instillation and there was no reaccumulation (Fig. 2). We noticed no immediate side effects related to OK­432 instillation. Medium chain triglycerides (MCT)­rich formula feeding was successfully switched to regular formula before discharge. The infant was discharged in good condition with improvement at five months of age. Discussion Congenital chylothorax is the accumulation of lymph fluid or chyle in the pleural space. The clinical course of chylothorax is highly variable and ranges from spontaneous resolution to progression into hydrops fetalis and fetal death. If congenital chylothorax is severe or develops in the second trimester, it may lead to pulmonary hypoplasia as a result of impaired lung growth by compression13). The prognosis mostly depends on the underlying etiology and associated conditions. Standard treatment algorithms are based on adequate drainage of the pleural fluid, in combination with parenteral nutrition or feeding with MCT­rich formula. With conservative treatment, complete resolution of pleural fluid can be observed within 30 days for 80% of congenital chylothorax patients14). However, there are no definite guidelines about which treatment is the most useful for persistent congenital chylothorax. Some authors recommend that surgical intervention may be necessary in cases with massive (50 mL/kg/ day) or persistent (>4 weeks after onset of the chylothorax) pleural drainage4,15). Recent reports have suggested octreotide or pleurodesis as an alternative medical therapy for infants with persistent chylothorax. Octreotide, a somatostatin analogue, has been used effectively in postoperative cases of chylothorax in both adult and pediatric patients. There have been several previous reports of the use of octreotide as a second­line treatment of congenital chylothorax that did not resolve with conservative treatment16,17). Its usefulness and relative freedom from side effects have been documented. However, caution is advised for patients prone to necrotizing enterocolitis because of the detrimental effects of somatostatin on splanchnic blood flow, especially for premature babies. In our first case study, octreotide infusion was initially started up to a maximum dose of 10 gµ/kg/hr for about two weeks, but no significant decrease in chest tube drainage was noted. Another treatment option is pleurodesis, which obliterates chylous leaks to obtain pleural adhesion. OK­432 (picibanil) is a lyophilized preparation of a low­virulence strain of group AS. pyogenes of human origin, inactivated by heating with penicillin G, and has been proposed as a sclerosing agent. It causes pleurodesis by inducing a strong cellular and cytokine­mediated inflammatory response. OK­ 432 has been widely used to treat postoperative chylothorax and cystic lymphangioma in children5­7). Recently, in fetal chylothorax, intrapleural administration of OK­432 has had favorable outcomes; 22 of 25 patients showed remission of pleural effusion after intrapleural injection since 20018­11). For its first use in neonates, Matsukuma et al.12) reported the successful use of OK­432 for the