Matthew A. Uhlman, MD, MBA
James A. Brown, MD, FACS
BASICS
DESCRIPTION
• Chyluria is the presence of chyle (a combination of lymphatic fluid and triglycerides) in urine
• Presents as milky white urine that can be constant or present primarily after meals
• Often self-limiting or resolves with conservative treatment including dietary changes
• Extended chyluria can lead to malnutrition, vitamin deficiencies, and immunosuppression (due to depletion of fat soluble vitamins) (1)[C]
EPIDEMIOLOGY
Incidence
• 2–10% of patients infected with filariasis can develop chyluria (2)[C]
• Extremely low rates of clinically significant chyluria (1)[C]
– Clinically significant in <1% of postsurgical patients
– Reports of subclinical chyluria based on CT in 3–41% of postpartial nephrectomy or radiofrequency ablation (RFA) patients (2,3)[C][B]
Prevalence
• 120 million people suffer from filariasis worldwide, primarily in Asia, Africa, Pacific Islands, and South America (2)[C]
• Chyluria is a manifestation of chronic infection, most often by Wuchereria Bancrofti, Brugia malayi, or Brugia timori (2)[C]
• Rare in developed countries
• Nontropical chyluria most often caused by trauma, renal surgery, infection, mass effect (AAA, tumor, abscess), pregnancy, or congenital abnormality (1)[C]
RISK FACTORS
• Parasitic chyluria
– W. bancrofti, B. malayi, and B. timori are primary causes of filariasis. All are transmitted by mosquito. Less common parasitic infections have been reported to cause chyluria (echinococcus, bilharzias, onchocerca, ascariasis) (1,2)[C]
• Nontropical chyluria
– Retroperitoneal surgery (most often radical or partial nephrectomy, RFA, or renal tumors) (1,3,4)[C][B]
– Trauma
– Mass effect: Retroperitoneal tumors (primary or metastatic) or lymphadenopathy
– Infectious: TB, abscess
– Aortic aneurysm
– Pregnancy
– Congenital fistula or lymphangioma
PATHOPHYSIOLOGY
• Parasitic
– Adult filariasis causes lymphangitis
– Obstruction of suprarenal lymphatics (thoracic duct or upper retroperitoneal lymph drainage)
– Results in rupture of lymphatic vessel into calyceal fornix, forming intrarenal lymphatic urinary fistula
– Lymphatic HTN, with valvular incompetence:
With obstruction between intestinal lacteals and thoracic duct, the resulting cavernous malformation opens into the urinary system, creating a fistula
Common fistula sites are renal fornix, pelvicalyceal system, trigone, and prostatic urethra
Primary causal agents: W. bancrofti, B. malayi, and B. timori
Less commonly caused by external compression or trauma
• Nontropical
– Disruption of peripelvic lymphatics during surgery allows backflow into pyelocaliceal system (1)[C]
– Congenital fistulous connections between urinary tract and lymphatic system have been described, primarily in children
ASSOCIATED CONDITIONS
W. bancrofti, B. malayi, and B. timori are considered the three causative agents of lymphatic filariasis. Mosquitos serve as vectors for all 3 nematodes (2)[C]
GENERAL PREVENTION
• Control of mosquito vector that transmits W. bancrofti, B. malayi, and B. timori (2)[C]
• Insect repellant and mosquito nets in endemic areas
• Diethylcarbamazine (DEC) fortified salt
• Annual DEC + albendazole are used to treat asymptomatic filariasis via action on microfilaria
DIAGNOSIS
HISTORY
• Patient complaints of intermittent or continuous milky or cloudy urine
– If intermittent, most often occurs following meals
• Country of origin of patient:
– Asia, Africa, Pacific Islands, South America
• Travel to tropical regions
• History of trauma
• History of renal surgery within prior 2 yr
• History of TB exposure/infection
• Significant weight loss, anemia, lower urinary tract symptoms (frequency, urgency, dysuria), hematuria, nutritional deficiency, proteinuria, or signs of immunosuppression
• Heavy chyluria can cause clot colic or, rarely, urinary retention
PHYSICAL EXAM
• Elephantiasis of lower limbs and genitals
• Lymphadenitis/lymphangitis
• Male groin exam may reveal hydrocele or epididymitis
• Palpable abdominal or flank mass
• Chylous output from surgical wound or surgical drain
DIAGNOSTIC TESTS & INTERPRETATION
Lab
• Urinalysis typically positive for albuminuria
• Postprandial urinary triglycerides
• Fat globules in urine identified by Sudan III stain
• Peripheral blood eosinophilia, may indicate parasitic infection
• Evaluate for TB if clinically indicated (tuberculin test, urine stain, and culture for acid-fast bacillus)
• ICT antigen card test (immunochromatographic card test, a commercial assay) is widely used in the diagnosis of W. bancrofti
• WB rapid and panLF rapid (2 commercially available assays) tests detect W. bancrofti, B. malayi, and B. timori
Imaging
• Abdominal/pelvic CT (3,4)[B]:
– Exclude retroperitoneal mass
– Fat fluid level seen in the urinary tract
– Can demonstrate contrast communication between collecting system and perinephric collection but does not show communications between perinephric collection and lymphatics
• Lymphangiography (traditional or magnetic resonance)
– Demonstrates abnormal lymphatics and entrance of contrast material into renal collecting system
• Lymphoscintigraphy
– Can be useful in delineating site of fistula, though not as precise as lymphangiography
• Retrograde pyelography
– Rarely warranted, but may show diffuse pyelolymphatic backflow
Diagnostic Procedures/Surgery
• Blood smear: Examine for microfilariae (early stage in life cycle of nematodes) using Giemsa stain
• Cystourethroscopy: Can help localize site of milky efflux of urine. Rarely, efflux seen from bladder or posterior urethra.
• Retrograde pyelography: Rarely warranted, but may show diffuse pyelolymphatic backflow
Pathologic Findings
Lipid contents of chyluria are mainly chylomicrons, 90% of which are in the form of triglycerides
DIFFERENTIAL DIAGNOSIS
• Filariasis from W. bancrofti, B. malayi, or B. timori
• Pyelolymphatic fistula
• Phosphaturia, most common cause of cloudy urine
• Pyuria
• Hyperuricosuria
• Nephropathy—urinary sediment can cause cloudy appearing urine
• Enterovesical fistula
TREATMENT
GENERAL MEASURES
• Nontropical
– Up to 50% of cases resolve spontaneously under dietary restriction (1)[C]
– Bed rest and/or use of abdominal binder to increase abdominal pressure may allow spontaneous closure.
– Medium-chain triglyceride (MCT) diet (avoidance of long-chain triglycerides)
MCTs are transported via portal system, not by chylomicrons through lymphatics
– Ureteral stent placement to reduce renal pelvis pressure
MEDICATION
Nontropical
Dietary modifications to reduce chylomicrons in diet—recommendations are often for fat-free or very low-fat diet, though this should not be observed for more than several weeks given the body’s need for some fats
Parasitic Chyluria
• DEC and albendazole, or ivermectin and albendazole
• DEC fortified salt can be used to treat and prevent lymphatic filariasis
SURGERY/OTHER PROCEDURES
• Procedures of choice involve disconnection of renal pedicle lymphatics (1,5,6)[C][A]
• Nephrolysis:
– Stripping and ligation of all lymphatic vessels to the kidney and upper ureter; open and laparoscopic techniques described
– Laparoscopic transabdominal and retroperitoneoscopic approaches described
– Success rates 80–98%; recurrence rates 3–25%
• Endoscopic coagulation of fistula
• Lymphangiovenous anastomosis with ligation of renal lymphatics
• Renal autotransplantation
• Nephrectomy was described prior to minimally invasive techniques
ADDITIONAL TREATMENT
Radiation Therapy
N/A
Additional Therapies
• Sclerotherapy with various agents instilled into collecting system (1,3)[C][B]
– Povidone iodine (5%) and dextrose (50%) in renal pelvic instillation sclerotherapy; 87% success reported
– Silver nitrate (1–3%) instillation into the affected collecting system causes sclerosis of lymphatic fistulas; 48% success reported
– Case reports of successful sclerotherapy with:
N-butyl-2-cyanoacrylate (component of medical cyanoacrylate glues)
Radiographic contrast media
Complementary & Alternative Therapies
N/A
ONGOING CARE
PROGNOSIS
• Rarely fatal, with high success rates reported for surgical intervention
• Recurrence rates after surgery reported as high as 25%
COMPLICATIONS
• Hypoalbuminemia and anasarca from massive protein loss (1)[C]
• Immunosuppression from fat soluble vitamin loss in chronic cases (1)[C]
• Underlying filariasis may cause epididymitis, hydrocele, and elephantiasis of the penis/scrotum and lower extremities
FOLLOW-UP
Patient Monitoring
• Treatment failures are readily apparent as urine returns to milky color (1,5)[C][A]
• Re-evaluate if chyluria recurs following treatment; consider the contralateral kidney as the source
Patient Resources
N/A
REFERENCES
1. Kim RJ, Joudi FN. Chyluria after partial nephrectomy: Case report and review of the literature. ScientificWorldJournal. 2009;9:1–4.
2. Tandon V, Singh H, Dwivedi US, et al. Filarial chyluria: Long-term experience of a university hospital in India. Int J Urol. 2004;11:193–199.
3. Panchal VJ, Chen R, Ghahremani GG. Non-tropical chyluria: CT diagnosis. Abdom Imaging. 2012;37(3):494–500.
4. Kaur H, Matin SF, Javadi S, et al. Chyluria after radiofrequency ablation of renal tumors. J Vasc Interv Radiol. 2011;22:924–927.
5. Zhang CJ, Chen RF, Zhu HT, et al. Retroperitoneoscopic renal pedicle lymphatic disconnection for chyluria in presence of complex renal vasculature. Urology. 2012;80:1273–1276.
6. Gomella LG, Shenot P, Abdel-Meguid TA. Extraperitoneal laparoscopic nephrolysis for the treatment of chyluria. Br J Urol. 1998;81(2):320–321.
ADDITIONAL READING
Kaul A, Bhadhuria D, Bhat S, et al. Chyluria: A mimicker of nephrotic syndrome. Ann Saudi Med. 2012;32(6):593–595.
See Also (Topic, Algorithm, Media)
• Chyluria Image 
• Filariasis, Urologic Considerations
• Urine, Abnormal Colored
CODES
ICD9
• 125.0 Bancroftian filariasis
• 125.9 Unspecified filariasis
• 791.1 Chyluria
ICD10
• B74.0 Filariasis due to Wuchereria bancrofti
• B74.9 Filariasis, unspecified
• R82.0 Chyluria
CLINICAL/SURGICAL PEARLS
• Milky or cloudy urine (often after meals) is the most common presentation, though phosphaturia is the most common cause of cloudy urine.
• W. bancrofti, B. malayi, and B. timori are the primary causes of filariasis, the most common cause of chyluria (parasitic chyluria).
• Following renal surgery, incidence of chyluria (up to 41% on CT) is likely much higher than is clinically significant (<<1%).
• Up to 50% of cases of chyluria resolve spontaneously with a medium chain fatty acid or very low-fat diet.
• There is no “best” imaging technique, though lymphangiography can demonstrate entrance of contrast from lymphatics into the collecting system.