Disfuncțiile șunturilor ventriculo-peritoneale cauzate de infecții multiple la copii: prezentare de caz

Introduction

An excessive accumulation of cerebrospinal fluid (CSF) within the brain of the children causes hydrocephalus, and the treatment of choice for these patients is the placement of ventriculoperitoneal shunts (VPS)^(1,2). The complications that might appear can be separated into three categories: mechanical failure (obstruction, fracture, disconnection, migration, perforation), infection (bacterial, parasitic or fungal) and functional failure (overdrainage, slit ventricle syndrome, pseudocyst, ascites, metastasis)⁽¹⁾.

One type of complication, the shunt infection, has an incidence that ranges from 5% to 12%, varying from study to study^(1,3). It can happen early after the procedure, within the first 6 months, or delayed, 6 months or more after the surgery^(1,3,4). Early infections are the most common and they are usually caused by bacteria from the patient’s own skin flora (Staphylococcus epidermidis, Staphylococcus aureus). Other pathogens found in early shunt infections could be Propionibacterium acnes, Haemophilus influenzae and Enterococcus species^(1,3,4). Delayed shunt infections are less frequent and they are caused by the spread of infection from other sites. In this case, the pathogen is often difficult to isolate⁽⁴⁾.

Fungal or parasitic infections are rare, affecting especially premature neonates and highly immunocompromised patients. The most common fungi that cause VPS complications are Candida species, out of which more than 75% are due to Candida albicans⁽⁵⁾. Morbidity and mortality increase in the infections with more-aggressive organisms (such as Gram-negative bacteria or Candida species), compared to infections from the skin bacterial flora (Gram-positive opportunistic pathogens)⁽⁵⁾.

There have been described a series of risk factors for VPS infections, such as low gestational age and preterm birth, young age at shunt placement, etiology of hydrocephalus (intraventricular hemorrhage, malignant disease, immunosuppression) and existence of postoperative CSF leaks^(3,6).

In the acute setting, VPS infections are harmful and severe, requiring antibiotic treatment (if they are of bacterial etiology) and additional surgical procedures.

Case presentation

A 2-year-old boy with a history of 5 VPS presents in February 2016 with decreased level of consciousness, lethargy and food refusal, symptoms of intracranial hypertension. The physical examination reveals spastic quadriplegia and lack of head and neck control. Under the presumption of shunt malfunction, the child is admitted to the Section of Paediatric Intensive Care Unit, at the University Hospital “Puerta del Mar”, Cádiz. After the neurosurgery consultation, a CSF specimen with purulent aspect from a shunt tap is obtained. Its analysis leads to the diagnosis of obstructive hydrocephalus secondary to shunt infection. Also, a cranial computed tomography (CT) scan is performed (Figure 1A).

The medical team of neurosurgeons decides to replace one VPS (from the left posterior parietal region, a Codman Hakim programmable valve) with an external ventricular drain (EVD). Analysis of the intraoperative CSF sample showed pleocytosis (299 leukocytes/µL - 63% polymorphonuclear cells and 37% mononuclear cells), 4000 red blood cells/µL, elevated protein level (235.7 mg/dL) and normal glucose level (43 mg/dL). Empirical antibiotherapy with ceftazidime and vancomycin was started, while waiting for the culture results.

Regarding the microbiologic diagnosis, the cultures from both CSF and previous surgical wound demonstrated the growth of Corynebacterium propinquum, with resistance to penicillin, erythromycin, azithromycin and fosfomycin, but vancomycin-susceptible. The post-operative evolution was good, the patient being afebrile, with respiratory and hemodynamic stability and normal state of consciousness. Also, bacterial growth was not present in the following samples. After an accidental removal of the EVD in the seventh day, the medical team decided to continue with the antibiotherapy and limit the invasive therapeutic interventions, due to his negative long-term prognosis. At this point, another CT scan was performed and interpreted by comparison with the one from admission (Figure 1B).

The medical history of the patient is relevant for the case, as it reveals his evolution as infant and toddler. He was born from the second pregnancy of a hypertensive mother. Following preterm caesarean birth due to placental abruption (at 31 weeks of gestation), the neonate of 1300 grams developed a hyaline membrane disease (respiratory distress syndrome). He required tracheal intubation, mechanical ventilation and two doses of surfactant.

During the 15^th day of life, the infant presented an abnormal head growth, with a size increase. The outcome of the transfontanelar ultrasound technique indicated a grade IV intraventricular hemorrhage. It was bilateral, with distended ventricles, affecting lateral and third ventricles (posthemorrhagic hydrocephalus). Besides, by the means of a cranial CT scan, he was diagnosed with bilateral periventricular venous infarction and cystic periventricular leukomalacia. The rate of growth in head circumference was superior to 1 cm/week and the newborn presented an increment in the intracranial pressure, with clinical and sonographic signs. After daily lumbar punctures without the reduction of ventricular dilatations, the patient was transferred the University Hospital “Puerta del Mar”, Cádiz, where a VPS has been placed in the right frontal area (programmable Codman Hakim valve system, adjusted at 50 mmH₂O and recalibrated afterwards at 60 mmH₂O).


 

After two months, the boy presented obstructive hydrocephalus and bacterial meningitis, due to the infection of the VPS by Klebsiella pneumoniae (resistant to amoxicillin). Antibiotic treatment (cefotaxime) was started and the VPS was replaced by an EVD with antibiotic-impregnated Bactiseal catheter (ventriculostomy). After a poor evolution, represented by the presence of ventriculomegaly with necrotic detritus, with signs of ependymitis (ventriculitis) and brain absces­ses, intrathecal gentamicin has been administrated. The remnant multiloculated postinfectious hydrocephalus needed the implantation of five VPS (Figure 2), in order to manage the drainage of excess CSF:

• VPS from the fourth ventricle to the peritoneum, without any valve.
• VPS entering the brain through the right parieto-occipital area, with Pudenz Flushing valve of low pression.
• VPS entering the brain through the right temporal area, with Pudenz Flushing valve of low pression (connected in “Y” with the prevous to the peroritoneum).
• VPS entering the brain through the left parieto-occipital area, with Codman Hakim programmable valve, adjusted at 30 mmH₂O.
• VPS entering the brain through the left temporal area, with Pudenz Flushing valve of low pression.

The child developed right clonic seizures and the electroencephalogram demonstrated hypsarrythmia (Figure 3). These features led to the diagnosis of West syndrome (infantile spasms). He was treated with vigabatrin and later with levetiracetam, baclofen and adrenocorticotropic hormone (ACTH), causing the appearance of Cushing’s syndrome.


 

After less than a year, a CSF specimen with purulent aspect from a shunt tap demonstrated the presence of another ventriculitis, with malfunction of the shunt. After the removal of the left parieto-occipital VPS, a temporary EVD with antibiotic-impregnated Bactiseal catheter has been placed. Intraoperatory samples of CSF and pus from the abcess were obtained and the results of the cultures showed bacterial growth of Enterococcus faecalis (resistant to gentamicin, tobramycin, amikacin, erythromycin, clindamycin, quinupristin/ dalfopristin, trimetoprin/ sulfametoxazol) and Corynebacterium amycolatum (resistant to penicillin and rifampicin). After the removal of the EVD, VPS was placed again (entering the brain through the left parieto-occipital area, with Codman Hakim programmable valve). During the following year, the child suffered another two valve and distal catheter replacements for the VPS which enters the brain through the left temporal area (Pudenz Flushing valve of low pression).

Discussion and conclusions

This case report shows that the placement of VPS in the pediatric population comes with the potential for increased complications. The management of such a complex case of hydrocephalus requires a multidisciplinary approach, in which the neurosurgeon plays the central role.


 

According to the guidelines of Infectious Diseases Society of America, empirical therapy for suspected VPS infection should be realised with a glycopeptide, if necessary in combination with ceftazidime, cefepime or meropenem⁽³⁾. Broad-spectrum antibiotics can be given to the patient until specific organisms are identified⁽¹⁾. Empirically, the antibiotics should be chosen depending on the resistance patterns in the community⁽¹⁾. After the performance of antimicrobial susceptibility testing, it is important to confirm susceptibility to the chosen empirical antibiotic. Otherwise, the treatment should be modified, based on the resistance pattern of the pathogen^(1,3). Beside the intravenous antibiotic treatment, the neurosurgeon can opt for intrathecal antibiotherapy, externalization or removal of the shunt^(1,7).

Current evidence-based guidelines suggest that CSF shunt infections should be treated by supplementation of antibiotics, with partial or complete shunt hardware removal⁽⁷⁾. In each case, clinical judgement will determine the preferred approach, as there is insufficient evidence to recommend an universal treatment⁽⁷⁾. Intrathecal antibiotic therapy is taken into consideration, alone or in combination with systemic antibiotherapy, but its adverse reactions (potential neurotoxicity, allergic and inflammatory responses) lead to a limited routine use⁽⁷⁾.

Prevention of VPS infections is advancing due to the development of antimicrobial shunt catheters. One meta-analysis showed that the use of antimicrobial-impregnated or coated shunt catheters reduce the risk of infectious complications in patients with hydrocephalus, but additional trials are needed to investigate their effectiveness⁽⁸⁾. 

Conflict of interests: The authors declare no conflict of interests.