Chyluria is ‘milky white’ urine due to the presence of chyle that enters the urinary drainage system as a result of fistulous communications with the renal lymphatics. Chyluria is a symptom and not a disease. It is rare in Europe but not uncommon in the tropics, particularly in areas where filariasis is common. Filariasis is the most common cause of chyluria. Wuchereria bancrofti, a viviparous nematode, accounts for 90 per cent of human filariasis. Man is the only host. The disease is spread by bites from mosquitoes (Anopheles or Culex): adult worms migrate to the lymphatics, where they cause obstruction. The disease affects 5 to 10 per cent of the population in the endemic areas of the Indian subcontinent. Chyluria is a late sequelae, seen in 1 to 2 per cent of such cases 10 to 20 years after initial infection, usually when active filariasis is no longer demonstrable.

Chyluria affects young males and females equally. It is painless, profuse, and intermittent because of spontaneous remissions and is often worse after a ‘fatty meal’. The loss of protein in urine causes hypoproteinaemia. Chylous clots may produce renal colic and urinary retention.

A clot is formed in the chyluric specimen of urine on standing, which on shaking with an equal amount of ether, does not dissolve. The presence of chyle in urine is confirmed by the estimation of urinary colloidal suspension of fat in the form of chylomicrons. Oral ingestion of fat leavened with Sudan Red Three turns the urine pink in those with chyluria but not in normal subjects, a test useful in differentiating chyluria from artefact.

The intravenous urogram is usually normal. Lymphangiography shows small nodes with dilated, plexus shaped lymphatics in para-aortic regions; retrograde filling of lymphatics running towards the hilum of kidneys appears to be the site of fistulization. Intravenous urography combined with lymphangiography usually demonstrates the site of lymphaticourinary fistulae (Fig. 2) 2772. Demonstration of fistulae by administration of protein tagged with radioactive isotope is a much simpler and non-invasive procedure. The isotope appears in the urine promptly, concentrates in the renal area, and does not drain down to the bladder after obliteration of lymphaticourinary fistulae.

Cystoscopy during the episode of chyluria or 2 h after a ‘fatty meal’ often confirms efflux of milky white urine from one or both the ureteric orifices.

No medical treatment will stop chyluria, but spontaneous remissions are common. Mild chyluria is managed with a low fat and high protein diet. High levels of fluid intake help to reduce the incidence of clot colic or clot retention. Surgical treatment should be reserved for patients with significant problems such as persistent clot colic, clot retention, and with significant hypoproteinaemia.

Operative procedures to disconnect the lymphatics from the kidneys involve mobilization of the kidneys, laying bare the renal vessels and upper ureter by dividing and individually ligating all the dilated lymphatics. Transient renal ischaemia during dissection around the renal artery occasionally results in permanent renal damage. Surgical capsulotomy and renal decapsulation have always met with poor results. Lymphaticovenous anastomosis to divert the flow of chyle into the venous system usually results in technical failure. Renal autotransplantation is rarely indicated for chyluria.

Passage of sclerosing agents such as 1 to 5 per cent silver nitrate solution, 15 to 25 per cent sodium iodide or potassium bromide, or hypertonic glucose or saline into the renal lymphatics through the pyelolymphatic channels, a potential communication that exists between the renal lymphatics and the pelvicaliceal system, produces lymphangiitis and finally fibrosis, resulting in obliteration of lymphaticourinary fistulae. Irrigation of the renal pelvis with 5 per cent silver nitrate solution helped to relieve symptoms in 90 per cent of our 200 patients with chyluria seen during the last 20 years.

Cystoscopy is performed 2 h after a fatty meal, consisting of 10 g of butter and a cup of creamy milk. The procedure is performed with local instillation of 2 per cent lignocaine, except in very apprehensive individuals who receive caudal block for anaesthesia. A balloon ureteric catheter is passed inside the ureteric orifice, effluxing chylous urine. The position of the ureteric catheter inside the renal pelvis is indicated by the sudden gush of urine and confirmed by imaging. If chyluria is bilateral the more severely affected side is irrigated first, the contralateral side being treated a week later.

The renal pelvis is filled with a measured quantity of distilled water until the patient experiences flank pain: this provides a rough estimate of the pelvic capacity. Equal amounts of freshly prepared 5 per cent silver nitrate solution are pushed forcefully through the ureteric catheter into the renal pelvis. As soon as the patient feels lumbar pain the silver nitrate is aspirated out and renal pelvis is thoroughly lavaged with distilled water. Frusemide is administered to induce diuresis. The ureteric catheter is removed after urine starts dripping from it. Before removing the cystoscope the silver nitrate is washed out of the bladder. Those with suspected bladder outflow obstruction are catheterized. Most patients feel sick and experience mild abdominal discomfort immediately or a few hours after the procedure. Those who develop transient haematuria and flank pain respond very well to this treatment. Clear urine suggests disappearance of chyle, and absence of urinary chylomicrons signifies obliteration of lymphaticopelvicaliceal fistulae.

Silver nitrate solution occasionally enters the bloodstream through the pylovenous flow and produces an anaphylactic reaction. High doses of hydrocortisone and fluids help to bring the situation under control. If silver nitrate enters the parenchymal tissue due to improper placement of ureteric catheter, cortical and perinephric abscesses develop, necessitating open drainage. If there is spillage of silver nitrate through the pelviureteric junction double-J stenting prevents ureteric stricture. Chemical cystitis which fails to respond to anticholinergics requires corticosteroids and repeated bladder distension to prevent bladder contracture.

This procedure, besides being easy to perform, seems to be a cost-effective treatment for chyluria in endemic areas. Chyluria commonly recurs in spite of open surgical procedures whereas this treatment can be repeated safely without any distortion of renal anatomy or risk to the patient.

Karanjaval DK. Lymphangiography in the management of filarial chyluria. Ann R Coll Surg Engl, 1970; 46: 267 - 76.

Diamond DE, Schapira HE. Chyluria—a review of the literature. Urology, 1985; 25: 427 - 31.