Liver Abscess as the Complication of Ventriculoperitoneal Shunt Associated with Skin Injury

Abstract

A 50-year-old male who had undergone ventriculoperitoneal shunt for hydrocephalus following acoustic neurinoma surgery 18 months earlier presented with progressive fatigue and loss of appetite. Three months prior to visiting our hospital, he fell off his bicycle and sustained a skin laceration just above the tube on the right clavicle. He exhibited tenderness in the right upper quadrant but no other neurological symptoms. A contrast-enhanced abdominal computed tomography scan revealed a large well-defined lesion in the right lobe of the liver, with the shunt tube having migrated into the lesion. Ultrasound-guided percutaneous drainage was performed, resulting in a diagnosis of liver abscess. Culture of the drainage fluid confirmed the presence of methicillin-resistant Staphylococcus aureus, and vancomycin therapy was initiated. Later, an increased cell count, predominantly neutrophils, was observed in his cerebrospinal fluid. We then removed the entire shunt system and administered linezolid, after which the cerebrospinal fluid cell count normalized within almost one month. Liver abscesses as a complication of ventriculoperitoneal shunt are rare, with only 11 cases reported in the previous literature. This is possibly the first case associated with traumatic skin injury occurring long after ventriculoperitoneal shunt placement. With proper management of the shunt tube and administration of the appropriate antibiotic treatment, a favorable prognosis can be expected.

Introduction

Intraperitoneal complications following ventriculoperitoneal shunt (VPS) as a treatment for hydrocephalus are considerably rare compared to those following shunt obstruction or meningitis. However, some cases of peritonitis, intra-abdominal abscesses or cysts, and tube perforation or migration to abdominal or pelvic organs, such as the colon, intestines, bladder, ureter, or scrotum, have been reported.^1-3) We experienced a rare case of a solitary liver abscess with shunt tube migration into the liver 18 months after VPS placement. It was possibly associated with a local skin injury at the shunt route site, and this is the first reported case of such a complication occurring long after VPS placement.

Case Report

A 50-year-old male visited our hospital complaining of abdominal pain, fatigue, and loss of appetite. These symptoms had worsened over the previous month. He exhibited tenderness in the right upper quadrant but no other neurological symptoms. Two years earlier, he had undergone surgery for an acoustic neurinoma, followed by VPS surgery for hydrocephalus. During this procedure, a shunt tube was inserted into the intraperitoneal space via a middle pararectal incision in his abdomen.

Three months prior to his visit, he had fallen off his bicycle and sustained a skin laceration just above the tube on the right clavicle. Later, pus discharge was observed from the laceration, but as it gradually subsided, the patient decided to wait and see without going to the hospital. Although the crust and scar were still visible at the time of his visit (Figure 1), no pus discharge was observed, and we did not perform a culture test. In addition, it was also unclear whether the shunt tube had been exposed at the time of the injury. Routine blood examinations revealed a white blood cell count of 11,000/μL, of which 83.5% were neutrophils, and a C-reactive protein level of 12.61 mg/dL. The liver enzymes, aspartate aminotransferase and alanine aminotransferase, were both below normal limits (21 U/L and 26 U/L, respectively). A contrast-enhanced computed tomography (CT) scan of his abdomen revealed a well-defined, hypodense, round lesion with marginal capsular formation in the right lobe of the liver. The tip of the tube in the intraperitoneal space had migrated into the lesion (Figure 2). A head CT scan showed ventricular enlargement compared to the scan performed three months earlier (Figure 3). He was finally suspected of having a liver abscess associated with VPS infection, for which reason he was admitted to our hospital. Since no visible pus discharge was observed, wound culture test was not performed. After admission, abdominal surgeons promptly performed ultrasound-guided percutaneous drainage of the lesion, confirming that the contents drained were white pus. The shunt valve was clamped immediately after the liver abscess was diagnosed. At this time, he had no fever and examination of his cerebrospinal fluid (CSF) revealed a cell count of 18/μL. Culture of the abscess drainage fluid confirmed the presence of methicillin-resistant Staphylococcus aureus (MRSA), so vancomycin therapy was initiated at a dose of 1,200 mg once daily.

Figure 1

Image of the crust and scar observed during the initial visit. It was observed just above the tube on the right clavicle, and it was located just near where the shunt tube was positioned.

Figure 2

A: A contrast-enhanced computed tomography (CT) scan shows the liver abscess along with the distal end of the peritoneal catheter (arrow). B: 3D reconstructed image showing the path of the shunt tube.

Figure 3

A: Head computed tomography (CT) scan performed three months prior to admission. B: Head CT scan performed after admission. Compared to the previous scan, ventricular enlargement has occurred due to shunt dysfunction.

The abdominal side of the shunt tube was scheduled for removal once the abscess had drained sufficiently to prevent pus from leaking into the peritoneal cavity. However, a few days later, he developed a fever and started vomiting. His CSF test results showed an increased cell count of 720/μL, which predominantly contained neutrophils. We therefore decided to remove the entire shunt system under general anesthesia. The tube was removed smoothly, with no abnormal findings such as damage or cracks on the tube itself, and the subcutaneous tissue along the tube also seemed normal. MRSA was also cultured from the tip of the ventricular tube. We changed the antibiotic from vancomycin to linezolid at a dose of 600 mg every 12 hours, and the CSF cell count eventually normalized after almost one month of treatment. As no progression of hydrocephalus has been observed on CT scans or in neurological symptoms since the shunt was removed, we have monitored the patient for five months without reconstruction of the VPS. If hydrocephalus gradually worsens, we will perform reconstructive VPS surgery as usual.

Discussion

In this case, we believe that shunt tube migration into the liver was associated with traumatic skin damage along the shunt route, subsequently developing into a liver abscess. Liver abscesses as a complication of VPS have been rarely reported, with only 11 cases found in the previous reports,^4-14) which are listed in Table 1. This is the only case that may be associated with traumatic skin injury occurring long after VPS placement. A liver abscess is often discovered alongside presenting symptoms such as fever, fatigue, and pain or tenderness in the upper right quadrant of the abdomen, as observed in our patient. However, it is usually caused by inflammation spreading from the biliary tract or by intestinal infections. The causative bacteria are therefore most commonly Escherichia coli or Klebsiella pneumoniae. According to our review series of shunt-related liver abscesses, staphylococcal species, including MRSA, were identified as the causative bacteria in six of ten cases, as in this study. This is the most significant difference between general and shunt-related liver abscesses. Abscess formation was either solitary or multiple and was always associated with a migrated tube. In nine of 11 cases, the period between undergoing VPS and the onset of clinical symptoms such as fever or tenderness was within three months. Only in one case, this occurred 24 months after VPS, but the causative bacterium in that case was Enterococcus. Although the mechanism by which the tube migrates and liver abscesses form remains unclear, Paone et al.¹⁰⁾ speculated that chronic aseptic inflammation of the Glisson's sheath, caused by mechanical stimulation from the tube tip, leads to fibrous encasement and fixation of the tube in place. Repeated irritation at the site then causes perforation. However, considering the superficial bacteria, such as staphylococci, and the relatively short period after VPS, as in previous reports, we propose that the mild infectious inflammation occurred at the abdominal tube tip due to the superficial bacteria that became attached during the surgery. This can lead to migration of the tube into the liver and subsequent local abscess formation. In this sense, the period of about two months from the traumatic injury to the onset of symptoms in our case is similar to intervals after VPS placement in previous cases, making it plausible that the liver abscess in our case developed from a wound infection. Unfortunately, we had not performed any radiological evaluations of his abdomen since confirming the appropriate VPS placement just after the surgery. Though we could not determine the exact timing of the tube's migration into the liver, considering that the shunt remained functional until this incident occurred, it is possible that the migration happened relatively recently, perhaps triggered by an infection followed by inflammation.

Table 1

List of Reported Cases of Liver Abscess Associating with VPS

No.	Report	Patient’s age/sex	Fever or abdominal symptoms	Abscess after VPS	Causative bacteria	Treatment for abscess	Shunt management	Meningitis	Outcome
CT: computed tomography; F: female; M: male; MRSA: methicillin-resistant Staphylococcusaureus; N/A: not applicable; VPS: ventriculo-penetorial shunt
1	Fisher et al. (6), 1984	31 / M	Fever	19 days	Corynebacterium	CT-guided drainage	Externalization	+	Recovered
2	Reddy (12), 1987	59 / M	N/A	3 months	Staphylococci / Enterococci	N/A	N/A	N/A	Recovered
3	Kohno et al. (8) 1987	31 / F	Fever and pain	3 months	Staphylococcus epidermidis	Ultrasound-guided drainage	Externalization	+	Recovered
4	Peterfy and Atri (11), 1990	24 / M	Fever and pain	21 days	Streptomyces albus	CT-guided drainage	Removal of VPS	N/A	Recovered
5	Paone and Mercer (10), 1991	2 / F	Fever and tenderness	24 months	Enterococcus faecalis	Laparotomy	Externalization	+	Recovered
6	Farrell et al. (5) 1994	48 / F	Fever and tenderness	N/A	N/A	N/A	Removal of VPS	N/A	Recovered
7	Mechaber and Tuazon (9), 1997	63 / F	Fever, vomiting and tenderness	30 days	Staphylococcus epidermidis	Antibiotic treatment	Externalization	+	Recovered
8	Huang et al. (7), 1998	4 months / F	Fever and vomiting	80 days	Enterococcus coli	CT-guided drainage	Externalization	-	Recovered
9	Shen et al. (13) 2003	53 / F	Fever	3 months	MRSA	Ultrasound-guided drainage	Externalization	+	Recovered
10	Borkar et al. (4) 2007	10 / F	Fever and tenderness	20 days	N/A	Antibiotic treatment	Removal of VPS	N/A	Recovered
11	Yang and Sim (14) 2013	50 / F	Fever	65 days	Staphylococcus capitis	Ultrasound-guided drainage	Continued detention of VPS	-	Recovered
12	This case	50 / M	Fever and tenderness	18 months	MRSA	Ultrasound-guided drainage	Removal of VPS	+	Recovered

The most concerning aspect of a VPS infection following skin complications is avoiding the development of bacterial meningitis.¹⁵⁾ In our literature review of 11 cases, meningitis was reported in five of them. Notably, all three cases with MRSA as the causative bacterium, including our case, resulted in meningitis. Therefore, treatment for a liver abscess following VPS placement involves either the immediate removal of the shunt catheter or the temporary externalization of the VPS, alongside aggressive antibiotic therapy and, if necessary, transhepatic drainage of the abscess. We were concerned that removing the tube from the liver abscess might cause peritonitis because the walls of the abscess are potentially more fragile and prone to leakage than those of pseudocysts,^16,17) which have a fibrous sheath around the tube. Furthermore, after the abscess was identified, clamping the valve to block CSF flow may actually have allowed bacteria to ascend through the tube lumen, leading to the bacterial meningitis. Even if the patient shows no clinical symptoms of meningitis or evidence of CSF infection during abscess treatment, we should immediately decide to remove the VPS tube or temporarily externalize the peritoneal tube in cases of identified liver abscess. Recently, laparoscopic drainage techniques, which allow direct visualization and irrigation if leakage of contents is observed, have become common in the treatment of liver or intraperitoneal abscesses,^3,18) alongside the administration of appropriate antibiotics. All reported cases have resulted in complete recovery with no recurrence, including this case. This suggests that the prognosis is favorable when the diagnosis is made rapidly and the appropriate treatment is administered. Finally, we emphasize that safe and definitive results should be obtained by draining the abscess and by carefully removing the shunt tube using laparoscopic techniques before meningitis develops in such cases.

This case has shown no significant progression of hydrocephalus so far, and the patient is currently under observation. It is known that hydrocephalus associated with an acoustic neurinoma may resolve spontaneously following tumor resection. In this case, although the ventricles were slightly enlarged at the time of onset, a shunt may not be necessary in the future. Regarding reconstruction methods, some authors recommend a ventriculo-atrial shunt in cases where only a short time has passed since an abdominal infection, as the peritoneal side of the shunt tends to malfunction within a few months of surgery.

Conclusions

We presented a rare case of a liver abscess as a complication of VPS long after placement that occurred in association with a traumatic skin laceration on the tube route. Even if the patient does not exhibit symptoms of meningitis, the shunt tube should be promptly removed, and the patient should receive appropriate antibiotic treatment, which can lead to a favorable prognosis.

Conflicts of Interest Disclosure

All authors have no conflict of interest.

Informed Consent

Informed consent for publication was obtained from the patient.

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