Movatterモバイル変換

Urine examination

Chyluria can be diagnosed by examining a freshly voided sample of morning urine. A fatty meal should be taken before voiding. On visual examination, chylous urine is milky in appearance and may contain fibrin and blood clots. The urine becomes clear on adding ether and bright red with ingestion of Sudan III mixed butter. Analysis of urine reveals chylomicrons and triglycerides. Estimation of urinary chylomicrons is the most specific and sensitive test for chyluria.4

Haematological examination

A haemogram typically shows eosinophilia.

Imaging

Intravenous urography, retrograde pyelography and lymphangiography are used to locate the lymphourinary fistulas. Recently, magnetic resonance pyelography and lymphoscintigraphy have also been used.6 If available, lymphangiography is an excellent diagnostic modality. It can demonstrate the site, calibre and number of fistulous communications. Findings include lymphourinary fistula at the level of the kidneys, ureters or bladder. The presence of lymphangiectesias may be noted. In 40% of cases contrast enters the pelvicalyceal system. Lymphangiography is rarely used nowadays as it is an invasive, time-consuming and technically demanding procedure. Lymphoscintigraphy is a non-invasive technique which uses Tc-99 m diethylenetriamine pentaacetic acid radionucleotides to demonstrate lymphourinary fistulas.4

Immunological examination

Filarial antigen detection in the urine and serum can be done with ELISA.7

The differential diagnosis of milky urine includes phosphaturia (dissolves with 10% acetic acid), amorphous urates, gross pyuria, lipiduria, pseudochylous urine and caseouria due to renal tuberculosis.

Conservative treatment

Patients with mild chyluria are managed with dietary restriction and drugs. Dietary restriction of long-chain triglycerides along with the use of medium-chain triglycerides is advocated. Dietary triglyceride restriction leads to prevention of chylomicron production by enterocytes and chyluria cessation. Medium-chain triglycerides (<12 carbon atoms) are directly absorbed via the portal circulation, bypassing the lymphatics.8 The use of coconut oil, which contains medium-chain triglycerides, is promoted. An Indian study has found that both the commonly used cooking medium in northern India ghee (clarified unsalted butter) and mustard oil contribute to chyluria, with ghee being the worst offender.9 Dietary therapy is combined with drugs. The commonly used drugs include diethylcarbamazine (DEC) (6 mg/kg/day for 21 days), albendazole (400–800 mg/day for 10–14 days), ivermectin (6–12 mg stat, repeated after 3 weeks) and benzathine penicillin (1.2 million units weekly for 12 weeks). We use a combination of drugs in most cases. DEC is the most widely used drug and has a selective action on microfilariae, which is the larval stage. Its action appears to be a change to the larval membrane so that they are phagocytosed by macrophages. Albendazole is a benzimidazole congener that kills parasites by inhibiting microtubular proteins. Ivermectin as a single dose has a potent action on parasites by blocking their neurogenic transmission. Rest and abdominal binders have also been found useful.

Two or three courses of drug therapy are given to the patient. Conservative management has a success rate of more than 70%. The factors associated with a poor response to treatment include higher grade disease, pretreatment with drugs and higher urinary cholesterol at baseline.10

Sclerotherapy

For patients not responding to conservative therapy, RPIS is used. It is based on the observation that the lymphourinary fistula is most commonly located at the renal pelvis. Injection of sclerosant here causes it to pass to the lymphatic channels and induce a chemical lymphatic reaction. The resultant oedema leads to blockade of the lymphatics and immediate relief to the patient. Permanent relief of chyluria occurs when the lymphatics heal by fibrosis. The procedure is performed under local anaesthesia or sedation. A fatty meal in the morning or previous night facilitates identification of the affected ureteric orifice. As the chyluria is intermittent, the orifice needs to be observed for 15 min or longer for diagnosis. Pressing the kidney through the abdominal wall also sometimes helps. A ureteric catheter is passed to the renal pelvis under radiological control and an amount of sclerosant equal to the renal pelvic capacity (7–10 mL) is injected. The instillation is done in the head-down position and continues until the patient experiences pain.11

The commonly used sclerosants include silver nitrate (0.1–1%), povidone iodine (0.2–5%), sodium iodide (15–25%), potassium bromide (10–25%), 50% dextrose, hypertonic saline (3%) or a combination of these. For instillation, an 8-hourly instillation for 3 days has been found to be superior to a weekly instillation for 6 weeks.12

Surgical therapy

Patients who do not respond to two or three courses of RPIS are labelled as ‘refractory chyluria’ and are considered for surgical therapy. Other indications for surgery include extensive weight loss, hypoproteinaemia, anasarca, recurrent clot retention, haematochyluria, recurrent urinary tract infections secondary to chyluria, altered immune status and psychological disturbances.16 Hemalet al17 classified chyluria into the following three grades based on involvement of the calyces on retrograde pyelography (RGP):

• Mild chyluria: involvement of a single calyx on RGP (figure 1A).

• Moderate chyluria: involvement of two or more calyces on RGP (figure 1B).

• Severe chyluria: involvement of most calyces with/without involvement of the ureter on RGP (figure 1C).

• Download figure
• Open in new tab
• Download powerpoint

Figure 1

Drawing showing amount of calyx involvement marked by dotted red line. (A) Involvement of single calyx. (B) Involvement two calyces. (C) Involvement of most of the calyx plus the ureter.

They advocated surgery in failed cases of mild to moderate grade and in those with severe grade of chyluria.

The operations described for chyluria include chylolymphatic disconnection, lymphovenous anastomosis, retroperitoneal lymphovenous anastomosis, transinguinal spermatic lymphovenous anastomosis, inguinal lymph node–saphenous venous anastomosis and autotransplantation or nephrectomy.

Stepwise approach to the management of patients with chyluria

• Suspected chyluria (white urine, haematuria)

• 

• Urinary triglycerides, urinary chylomicrons present

• 

• Dietary therapy, medium-chain triglycerides, DEC

• 

• Recurrence

• 

• Intravenous urography, CT scan, MRI

• 

• RPIS: betadine, silver nitrate (up to two courses)

• 

• Chylolymphatic disconnection (open or laparoscopic)

• 

• Recurrence

• 

• Lymphovenous, lymph node–venous anastomosis

• 

• Nephrectomy, autotransplantation

Mass chemoprophylaxis

An important strategy in the control of tropical lymphatic diseases such as filariasis includes mass chemoprophylaxis in endemic areas. Globally, the preferred regime is DEC 6 mg/kg along with albendazole 400 mg. In India a single dose of DEC is used. It is estimated that chemoprophylaxis has to reach 90% of the population for elimination of filariasis.24

Environmental measures

Filariasis is transmitted by mosquito bite of the generaAedes,Anopheles andCulex. These mosquitoes thrive around sources of stagnant water. Community and government participation to clean up the surroundings is essential to control the disease. The government carries out periodic spraying of dichlorodiphenytrichloroethane (DDT) and other disinfectants in endemic areas. Other personal measures to combat mosquitoes include use of mosquito nets and repellents.