Abdominal Complications in Patients with a Ventriculoperitoneal Shunt

Abstract

Hydrocephalus is a complex disease. The placement of a ventriculoperitoneal shunt is a treatment that has been in use since the 1960s. Although in recent years, the development of the endoscopic technique has gained importance in the treatment of hydrocephalus, the use of valves continues to be used. Valves can be associated with different complications. In this chapter, we develop the abdominal complications associated with these devices. Both in patients with abdominal pseudocysts and with intestinal infections or ascites, they should be studied with brain tomography, x-rays of the valvular system, and ultrasound. The first step of treatment in these patients is to define if the valve works correctly or not. The second topic to take into account is the presence of infection associated with the catheter, which is detected by taking a sample of cerebrospinal fluid. The treatment of these valve-associated complications in many cases requires an approach involving multiple specialists, general practitioners, infectious diseases specialists, and general surgeons, among others. In patients with ventriculoperitoneal shunt-related abdominal complications, surgical treatment depends on symptom severity and the possible associated infection at the time of diagnosis.

1. Introduction

Hydrocephalus is a complex disease, common in childhood, that can cause permanent damage to the development of cognitive functions. Hydrocephalus results from an imbalance between cerebrospinal fluid (CSF) production and absorption. Within the physio pathogenesis, they are classically classified into communicating and noncommunicating hydrocephalus.

Noncommunicating or obstructive hydrocephalus is due to the presence of a lesion within the ventricular system that causes its obstruction with the consequent accumulation of cerebrospinal fluid, for example, stenosis of the sylvian aqueduct or tumors.

The ventriculoperitoneal valve placement technique was developed in the 1960s. The ventriculoperitoneal valve is made up of three parts, a tubing that is placed intracranially, the valve reservoir, and the distal catheter that is inserted into the peritoneum. Despite the passing of the years, this treatment is currently used effectively in patients with communicating hydrocephalus [1, 2, 3].

Although in recent years, the endoscopic technique has been developed for patients with obstructive hydrocephalus. Placement of a ventriculoperitoneal catheter continues to be used.

The placement of ventriculoperitoneal valves is a surgery that is not free of complications. The most frequent VPS-related complications are infection and shunt malfunction. Shunt infection can be caused by various microorganisms. The causes of the malfunction of the shunt may be due to obstruction of the proximal catheter with choroid plexus (more frequent). The distal catheter can be cut with growth in pediatric patients. Occlusion of the valvular reservoir can also occur in patients with a large amount of protein in the cerebrospinal fluid, among others.

There are other less frequent complications than infection and valve obstruction that involve the gastrointestinal tract. Within this group of pathologies are the abdominal pseudocyst (APC), ascites, or complications related to the intestine. Knowledge of possible abdominal diseases in patients with ventriculoperitoneal shunt is important for proper management in these cases [1, 4, 5, 6, 7]. In this chapter, we propose management guidelines for patients with VPS-associated abdominal complications, such as APC, bowel-related complications, and ascites based on our experience at a tertiary-care hospital [8].

2. Patients with a VPS-related abdominal pseudocyst

Abdominal pseudocysts receive that name because they are not true cysts. They are produced by adhesion between the intestinal loops with the consequent accumulation of fluid [9, 10, 11, 12]. These pseudocysts lack their own wall or capsule. One of the possible theories to explain the physio pathogenesis is that the same material of the valvular catheter produces an inflammatory reaction of the intestinal loops, thus generating this fluid-filled cavity and preventing the catheter from functioning correctly. Another theory is that there is an infection with some germ that generates adhesion between the intestinal loops (Tables 1 and 2).

Table 1.

Management of patients with abdominal Pseudocyst, which cannot wait for the culture results, CFS cerebrospinal fluid, DCI distal catheter insertion, EVD external ventricular drainage, ETV endoscopic third ventriculostomy, US ultrasonography, VAS ventriculoatrial shunt, VPS ventriculoperitoneal shunt. Importantly, Conservative management is not advocated in any clinical scenario.

Table 2.

Management of patients with an abdominal pseudocyst and mild symptoms. CFS cerebrospinal fluid, DCI distal catheter insertion, ETV endoscopic third ventriculostomy, US ultrasonography, VAS ventriculoatrial shunt, VPS ventriculoperitoneal shunt. Importantly, Conservative management is not advocated in any clinical scenario.

This pathology should be suspected in patients who have had a ventriculoperitoneal valve placed and who present with fever, abdominal pain, and symptoms of intracranial hypertension. Since the correct functioning of the shunt may be affected by the presence of the abdominal pseudocyst [13, 14, 15, 16, 17, 18, 19], it is mandatory to perform complementary imaging studies to evaluate the shunt system.

A brain tomography should be performed to assess the size of the ventricles and some indirect signs of intracranial hypertension such as decreased subarachnoid spaces or the presence of periventricular transependymal edema. Radiographs of the system allow evaluation of the indemnity of the valvular system. It is recommended to perform a skull, thorax, and abdomen plate to evaluate the complete path.

The presence of a pseudocyst should be suspected when two abdominal radiographs show the tip of the catheter in the same position.

Abdominal ultrasonography is a useful and noninvasive method to confirm the presence of the pseudocyst by imaging. Although it is an operator-dependent method, which means that it requires the skills of the person who performs it, the tip of the distal catheter can be seen in contact with a hypoechogenic cavity.

In these patients, it should be initially suspected that APC may be associated with a shunt infection by a low-virulence or slow-growing organism [2]. As described in the literature, in recent years, about 41% of patients with abdominal valves and pseudocysts had an infection at the time of diagnosis [20, 21]. Due to this, we recommend ruling out the presence of a nervous system infection before deciding on surgical treatment. In a patient with VPS and an APC, a brain CT scan, radiographs, and abdominal ultrasound should be ordered to determine if the APC is causing the ventriculoperitoneal shunt to malfunction [7, 22].

In case of shunt malfunction, suspicion of APC is based on clinical manifestations (headache, fever, abdominal discomfort, etc.), lack of mobility of the distal tip of the catheter on routine x-rays, and is confirmed with abdominal ultrasound (US) (Figure 1). The latter study is safe and rapid and should be performed immediately as symptoms of shunt malfunction are already present [1, 4, 6, 7, 20, 23].

Figure 1.

Abdominal ultrasonography shows an anechoic fluid collection measuring 5 x 2 x 2 cm in the left iliac fossa, the region where the patient reported pain, around the tip of the distal catheter.

APC does not always cause the full spectrum of symptoms of intracranial hypertension syndrome [21]. It is recommended to collect CSF for culture, to rule out infection. The sample could be taken by lumbar puncture (LP), but sampling from the shunt is recommended because LP is not always possible, for example in patients with spinal dysraphism. Furthermore, in obstructive hydrocephalus, the lumbar cistern may not be in communication with the ventricular space [24, 25]. Some of the organisms responsible for this type of complication are slow growing. Therefore, it is recommended that the minimum reading time of the culture fluid be approximately one week (five to seven days).

It must also be taken into account that some microorganisms produce biofilm. Therefore, its recovery in cultures will be greater in prostheses, in this case, the ventriculoperitoneal valve.

After evaluating the CT scan, the severity of the symptoms of intracranial hypertension, and the degree of abdominal pain, we can classify patients as oligosymptomatic or asymptomatic. The treatment will be different according to the presence or not of severe symptoms.

In patients with an abdominal pseudocyst and symptoms of intracranial hypertension and/or ventricular enlargement on computed tomography or abdominal pain that is difficult to manage clinically with medication, it is recommended to remove the distal peritoneal catheter. The externalization of the distal catheter, that is to say, the removal of the system from the abdomen and its connection to a collecting system abroad should be carried out while awaiting the results of the culture [7]. To define the site where the outsourcing will take place, the patient’s anatomy must be considered.

We found the thoracic site the easiest and safest to outsource the shunt since it is easy to palpate in this region. If this is not the case, x-rays can be used to locate it in the operating room. However other sites may be considered. It is recommended to attempt to evacuate the APC by aspiration through the proximal end of the severed distal catheter before removing it from the abdominal cavity. It is important to consider that some catheters have a non-return mechanism at the tip that prevents aspiration of the cyst. Some authors consider the possibility of performing an abdominal tomography and aspiration puncture of the pseudocyst. We do not consider it necessary, since it is not a true cyst, only the withdrawal of the catheter allows the absorption of the liquid.

If a microorganism is isolated from the CSF culture collected from the reservoir, it is an infection associated with the ventriculoperitoneal valve. In this case, the system should be removed and an external ventricular drain (EVD) placed. Long-term treatment consists of reinsertion of the shunt. Ultrasound- or laparoscopy-guided repositioning into the peritoneum may be considered. Placement of a ventriculoatrial shunt (VAS) may also be considered [5]. The decision should be made after an evaluation together with the general surgeon. If the ventricular anatomy is favorable and the endoscopic third ventriculostomy (ETV) success score is high, then ETV can be considered [26].

In patients with an abdominal pseudocyst without shunt malfunction or with mild symptoms of intracranial hypertension and/or mild abdominal pain, the result of the CSF sample can be awaited without externalizing the shunt system. CSF reading is recommended for approximately one week (five to seven days) to rule out low-virulence and slow-growing pathogens. If no germs are present, a new distal catheter can be inserted at another location in the abdomen. Ultrasound or laparoscopy can be used as a guide. Reinsertion into the abdomen can also be avoided by diverting it to the cardiac atrium. In candidate patients, endoscopic treatment of hydrocephalus should be considered; ETV is another option.

In the case of a central nervous system infection, the shunt system should be removed and an EVD placed temporarily until the infection resolves. Once the infection is resolved, a new shunt system should be placed taking into account the same aspects as in patients with negative cultures.

The two main theories about the pathophysiology of APCs are that it originates from an infection and the other that APC is caused by an allergic reaction. Therefore, shunt infection should always be ruled out. In case the patient has mild symptoms or no symptoms and can wait for the final result of the CSF culture, it is recommended to change the distal catheter with a new one in another location or to perform an endoscopy.

There is no high-grade evidence to support the exteriorization of a system in oligosymptomatic patients without infection in the nervous system. We propose not to carry out the exteriorization in a systematic way, since surgery and/or superinfection of the valve can be avoided when exteriorizing it.

3. Patients with VPS-related bowel complications

Within this group, we consider patients with appendicitis, intestinal perforation, intestinal adhesions, intestinal volvulus, fistulas, plastron, anal extrusion of the peritoneal catheter, bladder perforation, abdominal wall perforation, and migration of the distal end of the catheter to the scrotal sac.

In this group of patients, it is also important to evaluate the functioning of the ventriculoperitoneal shunt valve with brain tomography and system radiographs. Because infections, intestinal rupture, among others. Can generate a malfunction of the shunt.

In patients with intestinal complications, the characteristics of the intestinal process and whether it is in contact with the distal catheter in the peritoneum should be assessed initially with abdominal ultrasound [27, 28, 29, 30, 31, 32]. The multidisciplinary evaluation of the patient is mandatory by a medical clinic, infectology, and general surgeons, because many of these pathologies are surgically resolved by the general surgery service. In case of an infectious process such as appendicitis, in contact with the catheter distal to the valve or perforation, exteriorization of the shunt at the thoracic level is recommended. The distal catheter is considered contaminated and must, therefore, be removed from the abdominal cavity [33]. A CSF sample for culture should be taken from all patients and culture results should be awaited before placing a new shunt.

In patients in whom the CSF culture is positive, it is most likely an ascending infection caused by germs of abdominal origin. As it is an infection in the nervous system, the entire shunt system must be removed and an EVD placed until the infectious process is resolved [7]. After completing the appropriate antibiotic treatment for the infection, a new catheter should be placed. Preferably in the atrium of the heart to avoid a new approach to the abdomen, abdominal surgeries and infectious processes predispose to the formation of intestinal adhesions and/or a peritoneum with less absorptive capacity. If the ventricular anatomy is favorable and the VTE success score is high, endoscopic surgery can be performed for treatment of hydrocephalus.

4. VPS-related ascites

Ascites are the abnormal accumulation of intraperitoneal fluid. Fluid accumulation occurs as a consequence of a nonabsorptive peritoneum. In addition to the clinical suspicion on physical examination, a globose abdomen, with an ascitic wave on palpation. Abdominal ultrasound is an imaging diagnostic method that, although it is operator dependent, is useful in diagnosing ascites (Figure 2). It is important to study the possible malfunction of the valve, so a brain tomography and x-rays of the system should also be requested [34, 35, 36].

Figure 2.

Abdominal ultrasonography shows the distal catheter and abundant peritoneal fluid (ascites). DC distal catheter, AC ascites.

In the case of the presence of ascites, CSF sampling is also recommended to rule out infection associated with the system. If the culture result is positive, removal of the shunt and placement of an EVD is recommended along with administration of antibiotics until resolution [37, 38].

If the patient has symptoms of intracranial hypertension, ventricular enlargement on CT scan, or dyspnea (respiratory distress) secondary to ascites, the shunt should be exteriorized while awaiting culture results. If cultures are negative, the site of choice for a new distal catheter is the atrium of the heart as reinsertion into the peritoneal cavity is not recommended [6, 35, 36] Although spontaneous resolution of ascites without the need for shunt intervention has been published, we recommend reinsertion of the catheter in a space other than the peritoneum [37]. If the patient is a candidate for endoscopic treatment of hydrocephalus, ETV could be considered.

Each patient must be managed individually based on their clinical context and the abdominal pathology associated with the shunt. The decision to remove the ventriculoperitoneal valve should be taken into account that CSF cell count, glucose, and protein may not be reliable indicators of infection and therefore do not justify immediate removal of the shunt [25].

5. Conclusion

DPVs have been used for the treatment of hydrocephalus for more than 60 years. Abdominal conditions in patients with shunts can make therapeutic decision-making difficult. The analysis of each case taking into account the presence of symptoms of intracranial hypertension and/or infection is important since in many cases a multidisciplinary team is required for treatment.