Successful management of a renal fungal ball in a pretermature neonate: A case report and review of literature.

Invasive fungal infection is common in the present day NICUs - generally manifesting as candiduria or candida sepsis. Fungal balls in the kidneys are very uncommon and most are amenable to higher antifungal agents. However, we had a child who did not respond to such measures and ultimately needed a surgical removal of the fungal ball in his kidney. We report this case along with a review of literature to highlight about this uncommon, but an important cause of persistent sepsis in pre-term infants and to review the treatment options including a surgical removal.

INTRODUCTION

In the current era of better survivals of low and very low birth weight babies and a widespread use of higher antibiotics, the incidence of fungal infection is commonly seen in high volume NICUs - particularly those that accept out-born babies from distant places.

Even though a vast majority of them subside with the regular anti-fungal agents, some of them require higher anti-fungal agents. We report a rare instance which warranted a surgical intervention for a fungal ball in the kidney.

CASE REPORT

A 34-week preterm male baby delivered by vaginal delivery, weighing 1.45 kg, was admitted to Neonatal Intensive Care Unit (NICU) for ventilatory assistance in view of prematurity related apneic episodes. During the course of its management, the child was detected to have bacterial sepsis and antibiotics were changed as per culture sensitivity reports. The baby also received parenteral nutrition through a central line in view of prolonged ileus secondary to sepsis.

Repeat blood culture sensitivity after 2 weeks yielded significant growth of Candida albicans. Blood urea and serum creatinine had also risen to 86 mg and 1.1 mg, respectively, perhaps due to fungal sepsis. Urine microscopy showed presence of yeast cells. Ultrasound of the abdomen revealed a 3.3-mm hyper echoic lesion in the left renal pelvis with mild hydronephrosis, suggestive of a fungal ball. The other kidney was reported to be normal.

The neonate was put on liposomal amphotericin B for 2 weeks as per standard protocol. But, candiduria continued with systemic sepsis and the size of the fungal ball remained the same, necessitating start of the next generation antifungal agent, voriconozole. No response was noted clinically and sonologically after 2 more weeks of treatment, although blood urea and serum creatinine had gradually returned to normal limits. The neonatologists were concerned about the continuing sepsis and persistent candiduria and the persistence of the fungal ball in the left kidney, with no response to the parenteral antifungal for over a month.

Hence, the child was referred for possible surgical intervention. Three options were considered, as follows:

Per-cutaneous nephrostomy insertion with irrigation of the pelvis

Cystoscopic insertion of a Double J stent

Open surgical approach

The first two options were considered not feasible in this preterm baby because of the small renal pelvis and there was also technical difficulty involved in stenting the 1.5-kg infant. Hence, an open surgical approach was selected.

OPERATIVE DETAILS

Left pyelotomy was done through an anterior retroperitoneal approach. The pelvis and peripelvic planes appeared healthy. A soft friable mass measuring 3 mm in diameter was noted in the pelvis [Figure 1], extending to the upper calyx, which was retrieved. The pelvis was thoroughly irrigated to clear any debris. A nephrostomy tube was placed for further irrigations. The wound was primarily closed without any perinephric drain. The nephrostomy tube accidentally expelled on the second postoperative day and hence the pelvic irrigations could not be done. Although the initial postoperative ultrasound showed a tiny echogenic material in the upper calyx of left kidney, it cleared on the subsequent sonograms done after 2 weeks. The blood culture was sterile, the urine cleared of Candida, and the baby was discharged on oral voriconozole for another 2 weeks. Repeat ultrasound scan after 2 weeks showed complete resolution.

Figure 1

Pyelotomy with removal of fungal ball

DISCUSSION

Invasive candidiasis is increasingly becoming a serious cause of late-onset sepsis in neonates and has a high mortality rate (25 to 35%) if not promptly and aggressively treated. Invasive fungal infection involving the urinary tract, eyes, meninges, spleen, liver, and joints is well known. About 35 to 42% of neonates hospitalized at NICU with candiduria have renal candidiasis, and a few of them are indeed fungal balls. Candida species are the 3rd most common organism (after coagulase-negative Staphylococcus aureus) isolated in late-onset sepsis in very low birth weight (VLBW) infants (<1500 g). It is the most common cause of urinary tract infection in NICU.

Various factors contributing to the development of fungal sepsis include the immune-compromised state, low birth weight, use of broad spectrum antibiotics, central venous catheters, prolonged urinary catheterization, and parenteral alimentation. [1]

Although urinary candidiasis is fairly common in the current day NICUs, invasive renal candidiasis leading to fungal ball is uncommon. Occasionally, it can end up as abscesses with unilateral or bilateral renal obstruction. Fungal balls in the urinary tract may cause long-lasting urinary obstruction and renal failure if adequate appropriate antifungal therapy is not promptly instituted.

The diagnosis of fungal sepsis in high-risk neonates is difficult and is often delayed or missed as there are no specific clinical features. Sustained decline in the platelet count of 10% per day or more in a neonate on broad-spectrum antibiotics for suspected sepsis may be indicative of fungemia. [2]

Ultrasound is a very useful investigation for diagnosis of renal fungal balls. It can be used to assess the dimensions of the lesion and, more importantly, the response to antifungal therapy. In the presence of candidemia and the absence of hematuria or pyuria, the calyces and the non-shadowing echo-dense material in the renal pelvis suggest renal candidiasis even without hydronephrosis. [3] However, it is operator dependent and a high index of suspicion is required during sonography for the correct diagnosis.

The initial management of renal fungal ball is medical with antifungal therapy. Many drugs are used including amphotericin B, flucanazole, and flucytosine. The response to these antifungal agents is usually good. In cases with incomplete obstruction, treatment with a combination of liposomal amphotericin B and fluconazole may cause resolution of the lesion and obviate the need for surgical intervention. [4]

Percutaneous streptokinase injection to renal pelvis through catheters has also been tried in conjunction with parenteral antifungal agents to lyse urinary fungus balls that are resistant to medical treatment and percutaneous drainage or irrigation. [5]

In fungal balls causing urinary obstruction and not responding to antifungals, surgical treatment in the form of percutaneous nephrostomy insertion with antifungal irrigation of the pelvis may be required. However, if the renal pelvis is not adequately dilated, per cutaneous nephrostomy would be difficult. In such situations, surgical removal of the fungal ball through a pyelotomy incision may be required.

However, this procedure is challenging and technically difficult due to small renal pelvis. The mobile fungal ball may be difficult to retrieve. Intraoperative use of flexible renoscope and ultrasound, if available, may help in precise localization and in ensuring complete clearance of the lesion. The pelvis needs to be thoroughly irrigated to clear the debris completely.

No guidelines are yet available for the indication, the mode of treatment, and duration of treatment in neonates and infants with obstructing fungal balls. Our case did not show any response to 2 weeks of liposomal amphotericin and 2 weeks of voriconozole. With persistent sepsis, candiduria, and persistient fungal ball in the kidney, surgical option was best in view of the size of the child, and we obtained good results.

This paper highlights the necessity for a prompt diagnosis and aggressive treatment of renal invasive candidiasis.

CONCLUSION

Renal candidiasis with fungal balls is a rare but important cause of morbidity and mortality in low-birth weight neonates. A high degree of suspicion is needed in preterm neonates with persistent fungal sepsis not responding to routine antifungals. A timely ultrasound scan can pick up the diagnosis. Although aggressive medical treatment with higher antifungal medications is effective in most cases, surgical intervention may be needed occasionally. In such cases, surgical removal can be safely accomplished.