Keywords
Chylous ascites - intranodal lymphangiography - therapeutic
Introduction
Chylous ascites (CA) is a rare type of ascites, rich in triglycerides and low-density
lipoproteins (LDL), occurring because of lymphatic leakage into the peritoneal cavity.
This is particularly rare in the pediatric population, with only ~ 100 reported cases,[1] iatrogenic injury to the lymphatic vessels being the most common cause. Most of
the cases which have been reported are those of post-retroperitoneal lymph node dissection
for germ cell tumors of testis or neuroblastoma. In our case, CA followed resection
of an intra-abdominal lymphangioma, which is particularly rare. Recently, there has
been increased interest in the diagnostic as well as the therapeutic utility of ultrasound-guided
intranodal lymphangiography with ethiodized oil (lipiodol; Guerbet Japan, Tokyo, Japan).[2],[3],[4] However, there are scarce reports on their utility in the pediatric population.[5]
We herein present a child with refractory postoperative CA who was treated by combined
ultrasound and fluoroscopy-guided intranodal lymphangiography with lipiodol.
Case Report
A 7-year-old male child presented to our tertiary care center with progressive abdominal
distention since birth. The child was antenatally diagnosed with a large cystic abdominal
lesion at 28 weeks of gestation, which was excised at 4 months of age. Histopathology
confirmed a diagnosis of lymphangioma. After a brief period of relief, there was a
recurrence of the lesion followed by re-excision at 3 years of age. This was followed
by progressively increasing abdominal distension with nonspecific abdominal pain.
Abdominal examination showed marked distention with mild tenderness. Abdominal ultrasound
revealed marked ascites. Paracentesis to study the nature of ascites showed a milky
and cloudy appearance of fluid with markedly raised triglyceride (1842 mg/dL), LDL
(435 IU/L), and cholesterol (86 mg/dL) levels suggestive of chylous nature of the
ascites.
Medical treatment with medium-chain triglyceride (MCT)-based, low-fat diet and inj.
octreotide 50 μg TDS followed by paracentesis with sclerotherapy was performed, which
failed to show any improvement. Dynamic magnetic resonance (MR) lymphangiography (dMRL)
was performed, wherein bilateral inguinal lymph nodes were punctured using 25-gauge
spinal needle under ultrasound guidance, which was secured and fixed. Injection of
5 mL diluted (1:1) gadobenate dimeglumine (MultiHance; Bracco International B.V.)
at 1 mL/min into bilateral inguinal lymph nodes simultaneously was performed followed
by careful positioning of the patient in the MR suite (Philips Ingenia, Best, the
Netherland). A T1-weighted 3D gradient sequence was acquired which was repeated sequentially
until the contrast leak was identified. The study revealed gross ascites with left
inguinal and abdominal wall lymphangiomas, with extravasation of contrast on the left
side of the pelvic cavity and rectovesical pouch, providing indirect evidence of leak;
however, the exact site of leakage could not be delineated [Figure 1]A.
Figure 1 (A-E): Intranodal MR lymphangiography image (A) showing pooling of contrast (thin arrow)
in the cystic spaces of residual lymphangioma in the left lateral pelvic wall and
ascites (asterisk). There is layering of contrast in the dependent part of the rectovesical
pouch (outlined arrow) suggesting contrast leak. Images (B and C) showing an intranodal
injection of lipiodol (thick arrow) which is seen to opacify the lymph nodes, lymphatics,
and the cystic spaces of lymphangioma. The post-procedure CT scan (D and E) showing
the distribution of lipiodol as well as leakage into the rectovesical pouch (CT: Computed
tomography, MR: Magnetic resonance)
In order to detect the site of the leak, intranodal lymphangiography was performed.
Under ultrasound guidance, the largest left inguinal lymph node was punctured with
a 25-gauge spinal needle. In order to reduce the needle movement after lymph node
puncture, the stylet of the spinal needle was removed and was attached to a connecting
tube, flushed with lipiodol. The needle tip was carefully positioned between the cortex
and fatty hilum of the lymph node. The rate of lipiodol administration was kept extremely
slow to prevent perinodal extravasation. A total volume of 5 mL of lipiodol was slowly
injected over a period of 10 min under serial fluoroscopic guidance. Inguinal lymphatic
vessels were visualized along with a globular area medial to Inferior iliac spine
suggesting filling up of the lymphangioma itself [Figure 1]B and [Figure 1]C. There was no passage of lipiodol proximally into the pelvic lymphatics or the
cisterna chyli. There was persistence of lipiodol in the inguinal lymphatics in the
follow-up CT obtained 48 h later [Figure 1]D and [Figure 1]E. The patient was followed-up after 7 days when there was a dramatic decrease in
the abdominal distension and ultrasound showed minimal residual ascites. There was
sustained remission of disease at 6 months after the procedure and the child has been
kept on follow-up.
Discussion
CA in the pediatric population is a rare type of ascites that develops most commonly
as a result of surgical disruption of the lymphatic system. It leads to local complications,
such as infection and delayed wound healing, as well as more grave systemic complications
like malnutrition and immune dysfunction because of the loss of triglyceride, lymphocytes
as well as immunoglobulins in the ascitic fluid.[6]
The therapeutic options include a trial of conservative therapy with (1) diet control
with low-fat, MCT diet; (2) total parenteral nutrition; (3) medical treatment with
somatostatin analogs like octreotide, and (4) large volume paracentesis with the addition
of sclerosing agents. It has been reported that 66% to 77% of patients can be successfully
treated by conservative methods.[7] On the other hand, a few authors describe that if drainage volume is >1000 − 1500
mL/day for >5 days, surgical repair of large lymphatic leaks or peritoneovenous shunt
placement should be attempted.[4] However, these procedures cause high morbidity and are often unsuccessful in cases
where there is leakage from small retroperitoneal and pelvic lymphatics.
Lymphangiography is a promising minimally invasive technique for the diagnosis as
well as the treatment of chyle leakage. Intranodal lymphangiography in contrast to
the conventional, more invasive pedal lymphangiography involves ultrasound-guided
access to the inguinal lymph nodes for direct puncture, requiring no incision and
bypassing the lymphatics of the lower limb, markedly reducing the procedural time,
contrast volume, and radiation exposure, proving to be that much more valuable in
the pediatric population.
The therapeutic effect of lipiodol in lymphangiography has previously been described
in adults; two articles describe a success rate of 65–89% in their 14 and 9 patients
series of refractory CA,[2],[4] respectively. The proposed mechanism for this effect is that lipiodol accumulates
near the point of leakage and induces a local inflammatory reaction, which is followed
by fibrosis.[7],[8] An interesting observation by Kawasaki et al.[4] was that higher success rate (100%) could be achieved in the minor leak groups as
compared with major leaks, as also seen in our case. This denotes a particularly valuable
role to lymphangiography in the niche group with minor and undetectable lymphatic
leaks, not responding to conservative therapy, as these leaks would be easily missed
and would not be amenable to surgical repair.
In conclusion, intranodal lymphangiography with lipiodol may play a valuable role
in the treatment of refractory postoperative CA in children, particularly in cases
of minor and undetectable leaks. MRL, being radiation-free modality, can be particularly
useful to distinguish major leaks from the minor ones in the pediatric population,
as in our case, and dictate the difference in management from surgical repair of lymphatic
leaks to lymphangiography using lipiodol.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms.
In the form the patient(s) has/have given his/her/their consent for his/her/their
images and other clinical information to be reported in the journal. The patients
understand that their names and initials will not be published and due efforts will
be made to conceal their identity, but anonymity cannot be guaranteed.
