Mechanical Block of Shunt Chamber Due to Fungal Growth in an Immunocompetent Child

Abstract

Invasive aspergillosis is a serious fungal infection caused by the proliferation and invasion of Aspergillus hyphae in tissue.1 Invasive aspergillosis is an increasing problem in immunocompetent patients after prolonged steroid therapy, cancer radiochemotherapy, and bone marrow or solid organ transplantation.2,3 Fungal ventriculoperitoneal shunt infections seem to be a complication of shunts placed in previously infected persons rather than nosocomial transmission during placement.4 We report a successfully treated case of shunt malfunction caused by mechanical block due to fungal growth inside the chamber in an immunocompetent child without systemic manifestations caused by Aspergillus fumigatus. CASE REPORT An 8-month-old female child with a case of congenital aqueductal stenosis with obstructive hydrocephalus underwent right ventriculoperitoneal shunt. Two months after surgery, she was apparently all right; then, again, she started to develop an increase in the size of her head. There was no history of fever and vomiting, and the child was playful and accepting feeds. On examination, anterior fontanelle was tense, and head circumference was 52 cm. Shunt tap was tried, but there was no flow of cerebrospinal fluid (CSF). The child was planned for shunt revision. During the procedure, the lower end was opened, but there was no flow of CSF even after pressing the chamber. After that, the upper end was opened; there was some whitish material in the chamber, and it was blocking the flow of CSF (Fig. 1). It was thought that it might be because of the collection of proteinaceous material. The material collected from the shunt tube and chamber was removed. Histopathology of whitish material collected from the shunt system showed fungal hyphae; after culture, there was growth of A.fumigatus (Figs. 2 and 3). These A. fumigatus isolates were identified by their cultural characteristics, their ability to grow at a temperature of 48°C, and the appearances of their conidiophores and conidia. Shunt tube was removed, and ventricular CSF was sent for fungal and bacterial culture and sensitivity. Ventricular CSF was sterile for both bacterial and fungal culture. In the meantime, the child was managed with ventricular tap. Later on, the shunt was placed on the opposite side, and the child was doing well.FIGURE 1: Whitish material in the shunt causing complete block.FIGURE 2: Photomicrograph showing fungal hyphae (left) that was characterized as A. fumigatus after culture (right).FIGURE 3: Photomicrograph showing fungal hyphaeDISCUSSION The central nervous system (CNS) involvement caused by Aspergillus species is very rare. This syndrome often manifests itself with fever and headache that may be present for several weeks before a diagnosis is established, and meningismus may be present but is nonspecific.2,5 Our child was not having any other complaints except a reincrease in the size of the head because the fungus was confined to the shunt system, and there was no systemic involvement. The CSF findings are inconclusive because, typically, only a small number of fungal cells are present in the CSF.3,6 Culture is the key to make the diagnosis, and it showed growth only in the shunt system, and there was no growth in the ventricular CSF in the present. This explains that, in the present case, the patient was not the source of infection as described in the literature;4 however, the shunt system got contaminated during the surgical procedure. The fact that establishing a diagnosis of CNS involvement due to Aspergillus is difficult and that many cases have been diagnosed only at autopsy indicates the gravity of the condition.7-9 Neutrophils (polymorphonuclear neutrophils) are the most important line of defense against Aspergillus hyphae, and they need the integrity of the immune system.1 The management of CNS aspergillosis is problematic because diagnosing the infection is difficult, and treatment should include a drug with activity against Aspergillus species that also penetrates into the CSF.5 Given the rarity of aspergillus meningitis, there is no standard therapy. Early antifungal treatment is the only chance of survival.3,5 Intravenous and intraventricular5,10 amphotericin B desoxycholate, itraconazole,11 and voriconazole2,5 have been tried in the management of cerebral aspergillosis with variable success. Despite increasing availability of antifungal drugs, the prognosis of cerebral aspergillosis is poor.2 These patients need a long-term treatment and follow-up.5 This case illustrates the importance of asepsis during surgery and careful handling of the shunt system during surgery.