Discussion
Chylothorax is a rare but life-threatening condition in neonates,
particularly in neonates with chromosomal abnormalities. It is well
known that chylothorax is often seen in children with chromosomal
abnormalities, such as trisomy 21, Turner’s syndrome, and Noonan’s
syndrome due to vascular and lymphatic
malformations2). Conservative treatment using
MCT-based formula, octreotide, somatostatin analogues, or
corticosteroids has traditionally been performed due to their effect on
splanchnic circulation and lipid absorption4). With
conservative treatment, complete resolution of pleural fluids can be
observed within 30 days for 80% of congenital chylothorax
patients5).
However, there are no definite guidelines about which treatment is the
most useful for persistent chylothorax. Some authors have suggested that
surgical intervention may be necessary in cases with massive or
persistent pleural drainage6,7). However, surgery such
as pleuroperitoneal shunting, thoracic duct ligation, and
lymphaticovenous anastomosis, should be performed only when conservative
treatments fail, as such approaches are highly invasive in children.
Pharmacologic or chemical pleurodesis has also been suggested as a
possible alternative step before surgery in pediatric patients, with
instillation of various agents (OK-432, bleomycin, tetracycline,
povidone-iodine) in the pleural space8). However,
there are no recommendations about which agent is the most useful for
managing chylothorax.
OK-432 is an inactivated preparation of Streptococcus pyogenesthat is an effective sclerosing agent9). It causes
pleurodesis by inducing a strong cellular and cytokine-mediated
inflammatory response and has been widely used to treat macrocystic
lymphatic malformations in children10). Although the
successful treatment of neonatal and prenatal chylothorax by
intrapleural instillation of OK-432 has been
reported3,5,7), there are only a few reports in
neonates with chylothorax, with reports concerning such patients with
chromosomal abnormalities being even rarer. Furthermore, there have been
no reports concerning the efficacy of pleurodesis using OK-432 for
high-risk patients, such as a low-birth-weight infant with 18 trisomy.
We selected OK-432 because it was allowed for the treatment of
chylothorax under the insurance system of our country and had fewer side
effects than other agents5). Regarding the dosage,
previous reports described the injection of 0.5 KE OK-432 for
pleurodesis3). In our case, 1 KE OK-432 (at a
concentration of 1 KE in 10 ml normal saline) was injected into the
pleural cavity, as substantial chylous effusion was noted, so the
concentration of OK-432 might have become diluted. OK-432 was
ineffective at the first two sessions due to the shortness of the clamp
time because of the patient’s respiratory disorder associated with
increasing pleural effusion. Therefore, at the third pleurodesis
session, the concentration was changed from 0.1 KE/ml to 0.2 KE/ml, and
1 KE of OK-432 was injected. The chylous effusion gradually decreased
due to the increased concentration of OK-432, and chylothorax was
ultimately cured after performing pleurodesis five times.
OK-432 is useful for refractory chylothorax, but there are some side
effects, including a fever and respiratory disorder5).
A fever was observed in the present case after pleurodesis but resolved
within a few days. Furthermore, this patient was able to finally be
withdrawn from mechanical ventilation at 143 days of life. Now, only
oxygenation with a 0.5-L nasal cannula is required at 1 year old, and
chest X-ray has shown that the lung field is
clear.