Rare Cases of Filarial Chyluria in Children

Introduction

Lymphatic filariasis (LF) is a mosquito-borne tropical disease that causes significant disability. The World Health Organization (WHO) estimated that LF is found in 81 tropical and subtropical countries with 120 million infected cases and one billion people at risk; 947 million people are threatened, whereas this infection disfigures 40 million people. ¹ About 90% of the estimated 120 million cases of LF in the world are caused by the filarial parasite Wuchereria bancrofti.² In children, microfilariae nest in the lymphatic system post-infection remains subclinical for years. It gives rise only to non-specific presentations of adenitis/adenopathy hence difficult to recognize. However, after puberty, adult disease syndromes like lymphoedema and hydrocoele manifest.³ Recognizing LF by atypical presentation like chyluria in children and timely diagnostic tests have therapeutic and preventive implications.

Novelty

Our cases highlight rare clinical presentation of LF in children along with the use of newer point of care diagnostic tests and management strategies.

Case Presentation

We report two cases who presented in the pediatric outpatient Department of a tertiary care hospital with the intermittent passage of milky white urine after obtaining written informed consent for publication of their details from the patient kin. Institutional ethical committee of Dr Ram Manohar Lohia Institute of Medical Sciences approved the study and granted approval to publish the case details.

Case 1: an 8-year girl with a history of undocumented fever for one year with the passage of white urine. There was no accompanying abdominal pain, dysuria, hematuria, decreased urine output, edema, or burning micturition. There was no aggravating or relieving factor, no history of abdominal trauma. On examination, mild pallor was present, the physical examination was normal.

Investigations

Blood serum chemistry showed normal complete blood counts (hemoglobin 10.5g/dL, white blood cell 7x109/L, platelet count 250 x10^9/L).Eosinophil count normal. The peripheral blood film showed microcytic hypochromic anemia with no parasites. Renal function tests and serum electrolytes were normal. Serum albumin level was 3.2 g/dL (normal range: 3.5–5.5 g/dL), total cholesterol level was 180mg/dL (normal range: 120–220 mg/dL), and serum triglycerides were 128 mg/dL (normal range: 80–150 mg/dL). Urine was milky white in color (Figure 1) and albumin was (2+), urine triglycerides was 140 mg/dl, which was high. 24-hour urinary protein was 1.5 gm/day. The absence of nephrotic range proteinuria, edema, hypoproteinemia, and hypercholesteremia ruled out nephrotic syndrome. Urine did not clear on heating and on adding 10% acetic acid suggesting the absence of urates and phosphates, respectively. Timing of symptoms and ultrasonography of the abdomen ruled out any congenital causes. Furthermore, since urine triglycerides were high, we did a blood examination for filarial antigen (CFA), which was positive.

Figure 1 White urine/chyluria (Case 1).

Case 2: 10 years old girl presented with poor appetite and not gaining weight. She revealed intermittent passage of white urine since one year. She was afebrile with a normal systemic examination. Her weight for age was 20 kg (less than 3 SD for age), BMI was 12.5, which was less than 3rd centile for age.⁴ Investigations showed normal blood counts. Peripheral smear was also normal. Renal function tests, serum albumin and Serum cholesterol level, serum electrolytes were normal. Urine was milky white (Figure 2). Urine protein was negative, and urine triglycerides was high at 135mg/dl, which raised the suspicion for filaria. After ruling out nephrotic syndrome, we did a filarial antigen (CFA) test, which was positive. It is a very sensitive test for diagnosing Wuchereria bancrofti infections.

Figure 2 Chyluria (Case 2).

Treatment

The etiology of chyluria was filaria in both cases, which showed remission after treatment with diethylcarbamazine (DEC) (6 mg/kg/day) for 21 days. The urine had completely cleared.

Dietary modifications of low fat and high protein diet (2–4 gm/kg) were done along with medium-chain triglycerides(MCT) supplementation.Fat-soluble vitamins ADEK were given inappropriate doses.

Advice to Parents

Since it is a mosquito-borne disease, proper measures to prevent mosquito bites are advised. Urine had completely cleared after two weeks. Antigen tests done at six weeks were negative for microfilariae. Both children were afebrile and also showed improvement in their appetite. Follow-up was done for six months. There were no recurrences.

Discussion

In children, intermittent chyluria is often missed. They are investigated and treated for common conditions like nephrotic syndrome characterized by the passage of white urine due to loss of significant amount of proteins, which is more than 1gm/m2/day.⁵ Index of suspicion should be high for filaria, and timely diagnosis is important for early treatment. There are only a few case reports in children of lymphatic filariasis.^5–8 Differentiating from nephrotic syndrome is necessary to avoid unnecessary renal biopsies^9,10 and treatment.There are reports¹¹ of adult patients having chyluria who were misdiagnosed and aggressively treated with immunosuppressive drugs. Other causes of white urine are the presence of urates and phosphates, congenital abnormal lymphatic-urinary communication, and post abdominal trauma.^12,13 White urine having urates clears on heating, and phosphaturia clears on adding acetic acid.⁸ Our patients tested negative for both. Chyluria can be diagnosed by the presence of triglycerides in urine, as in our patient. Other urine tests are mixing a milky urine sample with equal amounts of ether, which clears it, and oral ingestion of fat labeled with Sudan III, which causes orange, pink discoloration of urine.¹⁴ We did not do these tests in our patients.

Chyluria occurs due to intestinal lymph drainage following dilatation and rupture into the urinary tract due to obstruction.^15,16 Congenital abnormalities of the lymphatic vessels, malignancy, lymph urinary fistulas secondary to renal injuries are causes of non-parasitic chyluria.^17–19 Most cases of parasitic chyluria are by Wuchereria bancrofti filariasis.¹

Transmission

Adult worms nest in the lymphatic vessels for 6–8 years, disrupting its normal function. Subsequently, they produce millions of immature larvae or microfilariae, which circulate in the blood. Mosquitoes are infected with microfilariae while taking a blood meal of an infected host which subsequently spreads to others. Mature parasite larvae are deposited on the skin of humans. They then migrate to the lymphatic vessels, thus continuing the transmission cycle.²⁰ Chyluria is rare in children, with no clear-cut diagnostic approach and management strategies.

Diagnosis of Filaria

Childhood LF is incompletely documented due to the lack of specific clinical features and limitations of previously available diagnostic methods. Most published surveys based their diagnosis of infection on smear examination. Demonstration of microfilaria in blood is a specific test but lacks sensitivity, especially in children where adult worms are present but no microfilariae.²¹ The microfilariae can be detected directly through blood smear examination or DEC-provocative test.

However, in our patients, the smear was negative. Alere Filariasis Test Strip (FTS) – is a qualitative, point-of-care diagnostic tool that detects Wuchereria bancrofti circulating filarial antigen (CFA) in human blood, serum, or plasma.^21–23 Usage of the point-of-care rapid diagnostic test is essential for early detection.

Dietary therapy is of paRamount importance in children with chyle leaks as it aims to improve nutritional status and maintain hydration and electrolyte balance also decrease chyle production.²⁴

As per available literature,^24,25 dietary modifications like fat-free/very low-fat diet (a diet containing <0.5 g fat per serving), increased intake of MCTs like coconut oil and a high-protein diet is beneficial. Medium-chain triglycerides (MCT) are recommended to treat chyle leaks. Consumption of cereals, fruits, and vegetables would further improve the nutrition status of children with chyluria. Nutritional status must be monitored; fat-soluble vitamin and essential fatty acid supplementation is of paramount importance.

Conclusion

Both our patients had chyluria due to lymphatic filariasis, which is rare in children. A high index of suspicion is required regarding its clinical manifestations. Circulating filarial antigen-(CFA) is an important point of care test. Proper Medical management is required for complete remission and to prevent recurrences, along with dietary management.