Conservative management of chylous leak after open radical nephrectomy in an adult patient: a case report and literature review

Chylous ascites is rare but still a recognized complication of retroperitoneal surgeries caused mostly by inadvertent trauma to lymphatic channels. In this article, we present a case report and literature review of adult patient, with malignant tumor of upper urinary tract, who developed chylous leak after open nephrectomy. We present a case of chylous leak for a 67-year-old female patient, presented to urology clinic with complaining of left loin pain and gross hematuria, found to have upper urinary tract tumor, she underwent open radical nephrectomy with lymph nodes dissection, and postoperatively she had chylous leak that is treated conservatively using octreotide and spironolactone without the need for total parenteral nutrition. Conservative management should always be the first choice of management of chylous leak and chylous ascites. Careful anatomical identification and securing of the periaortic lymphatics are needed to decrease the risk of postoperative chylous leak and ascites.


Background
Chylous ascites defined as the accumulation of lipid-rich lymph in the peritoneal cavity is an uncommon complication after open radical nephrectomy. It carries significant morbidity and increases both the cost and hospital stay [1].
The postoperative chylous ascites is related to inadvertent disruption of lymphatic channels during the surgery [2]. Because the incidence of postoperative chylous ascites is low, no level-one evidence can be made on the treatment of chylous ascites though most specialists start conservative management first and reserve surgical management for refractory cases [1,2].
Most reported urological cases in English literature are those after laparoscopic nephrectomy and donor nephrectomy. There are only few reported cases of chylous ascites after open radical nephrectomy/nephroureterectomy, only one of them was performed for upper urinary tract urothelial carcinoma. To our knowledge, we present here the first case of chylous leak after open radical nephrectomy with lymphadenectomy for upper urinary tract urothelial carcinoma that was treated conservatively without the need for total parenteral nutrition (TPN).

Case presentation
A 67-year-old female patient presented to our clinic with history of left loin pain and gross hematuria. She had also loss of appetite and significant weight loss over the last 3 months. She is a heavy smoker with history of ischemic heart disease. She had no previous surgeries. Physical examination revealed a large palpable left upper quadrant mass. Her preoperative complete blood count, kidney function tests, electrolytes and liver function tests were within normal limits. Computed tomography (CT) scan revealed a large soft tissue mass arising from the left kidney (8 × 7 × 13 cm) with few hilar necrotic lymph nodes (Figs. 1, 2). There was an ill-defined necrotic nodule of about (3.5) cm on the left adrenal gland. There were no other distant metastatic lesions, and the right kidney was looking normal.
An open left radical nephrectomy was performed through an intercostal incision in which the mass (involving the kidney and adrenal gland) and the hilar lymph nodes were removed en bloc. The peritoneum was opened and part of it excised with the mass. No lymphatic leak was noted intraoperatively, and a drainage tube was inserted. Histopathology revealed high-grade urothelial carcinoma with sarcomatoid features, central necrosis, and perinephric fat invasion, two out of eleven perihilar and three out of nine perinephric lymph nodes were positive for malignancy.
The patient was doing well and resumed oral diet on the second postoperative day (POD), on the next day, she started to have whitish milky output drainage through the abdominal drain (250 ml/day), at this point we had two main differential diagnoses; chylous leak and pancreatic fistula, but the biochemical analysis was consistent with chyle. On POD 4, the patient was started on low salt, low fat and high protein diet which resulted in a drop in the chylous output to about (100 ml/day). On the POD 6, the patient was started on octreotide injection (0.1 mcg three times a day) and spironolactone. The chylous leak resolved so the drainage tube was removed on the POD 10 and the patient received a long acting somatostatin analogue (20 mg given as a depot muscular injection). She was discharged and advised to stay on low fat diet for further 3 weeks. Upon follow-up for 3 months, the patient was doing well with no abdominal distension nor leak from the drain site.
To the best of our knowledge, only few cases of chylous ascites after open nephrectomy/nephroureterectomy for adult patient with malignant pathology are reported in the English literature. A summary of our literature review is provided in (Table 1).

Discussion
Chylous ascites is the accumulation of triglyceride-rich lymph in the peritoneal cavity, which can be classified into primary and secondary, the primary is caused by congenital lymphatic system dysfunction while the secondary chylous ascites can be caused by malignant process, infection, trauma, and postsurgeries [10,11].
The incidence of chylous ascites after open donor nephrectomy is (0.6%) and (2%) after laparoscopic donor nephrectomy [12]. Some experts hypothesized that the use of bipolar and other energy devices rather than clipping in laparoscopic surgery has contributed to the higher incidence of chylous ascites in laparoscopic surgery compared to open renal surgery [13].
The lymphatic drainage of the abdomen, pelvis and lower limb goes into paralumbar trunks which joins the intestinal trunks to form the cisterna chyle [14]. So paraaortic dissection of renal artery may result in injury to paralumbar lymphatic trunks resulting in chylous leak and chylous ascites. Because of the anatomical proximity of left renal artery, aorta, and paralumbar lymphatic trunks, chylous ascites is more common after left nephrectomy compared with right nephrectomy comprising (75%) to (99%) of all cases of chylous ascites [14,15].  Lymphadenectomy increases the risk of postoperative chylous ascites [13]; a retrospective study done by Kim et al. concluded that the incidence of chylous ascites is three times more common if lymphadenectomy is done [15].
Patient with chylous leak usually present on POD 4 [16], but can present as early as POD 0 [7], and can be as late as few weeks or months postoperatively [16]. The clinical presentation of chylous ascites and chylous leak differs whether there is a drain or not, patients with drain are usually presented with persistent drainage of milky fluid, while those without drain or those whose drain removed early are presented with abdominal distention, pain, nausea, or less commonly presented with chylous discharge from the wound [15].
The diagnosis of chylous ascites is not difficult but needs high index of suspicion, to confirm the diagnosis many experts use biochemical analysis of the draining fluid and abdominal imaging such as ultrasonography and CT scan, and more invasive imaging modality such as lymphangiography and lymphoscintigraphy is used sometimes when surgical intervention is planned to localize the site of lymphatic disruption [1].
Because of limited number of reported cases of chylous leak after open nephrectomy for adult patients with malignant renal tumors, management of this complication has been guided by reports from other specialties [16]. In general, most patients with chylous ascites after abdominal surgery are successfully treated conservatively [16], and that is consistent with our literature review [3][4][5][6][7][8]. The conservative management consists mainly of diet modification (high protein, low fat, medium-chain triglyceride diet), keep NPO and TPN, paracentesis especially helpful in patient without drain [5,6,9], some medications may be helpful such as octreotide and diuretics, the exact mechanism of octreotide is not completely understood, but it has been shown to decrease the intestinal absorption of fats and decrease the lymphatic flow and thus improves the chylous ascites [16][17][18].