May Acute Appendicitis Complicate the Management of Pseudotumor Cerebri in Shunt-Dependent Patients? A Paediatric Case Report

Abstract

Introduction

Shunt-dependent secondary pseudotumor cerebri may remain clinically stable for many years; however, intra-abdominal sepsis such as perforated appendicitis can necessitate abrupt shunt removal, eliminating cerebrospinal fluid (CSF) diversion and precipitating sudden, vision-threatening intracranial pressure (ICP) elevation.

Case Presentation

A 17-year-old girl with a long-standing ventriculoperitoneal shunt for a childhood arachnoid cyst initially developed papilledema that was successfully managed with the addition of a lumboperitoneal shunt. Nine months later, she presented with perforated appendicitis requiring emergent appendectomy and removal of both shunts because of the high risk of ascending shunt infection. Although visual acuity was initially preserved after surgery, rapidly progressive bilateral papilledema developed within days, accompanied by marked retinal nerve fibre layer thickening and enlarging visual field defects despite maximal acetazolamide therapy. As reinstitution of CSF diversion was not feasible, bilateral optic nerve sheath fenestration (ONSF) was performed as a vision-preserving intervention. Visual acuity, visual fields, and papilledema improved promptly and subsequently normalised.

Conclusion

Perforated appendicitis in shunt-dependent patients may precipitate abrupt, vision-threatening ICP elevation following unavoidable shunt removal. Abdominal pain in patients with a history of CSF diversion should raise immediate suspicion for intra-abdominal sepsis. Early recognition of appendicitis may prevent perforation-related shunt complications, and timely ONSF is critical to avert permanent optic nerve damage when CSF diversion cannot be promptly restored.

Introduction

Pseudotumor cerebri is characterised by elevated intracranial pressure (ICP) in the absence of an intracranial mass lesion or hydrocephalus and is most commonly manifested by papilledema and headache. While idiopathic intracranial hypertension (IIH) represents the most frequent form, secondary pseudotumor cerebri may occur in association with structural abnormalities or altered cerebrospinal fluid (CSF) dynamics, including long-term shunt dependency. Ventriculoperitoneal (VP) and lumboperitoneal (LP) shunts can provide sustained ICP control; however, patients remain vulnerable to abrupt decompensation when shunt function is interrupted. Intra-abdominal sepsis, particularly perforated appendicitis, may necessitate urgent shunt removal because of the risk of ascending infection, potentially leading to rapid ICP elevation and vision-threatening complications. We present a paediatric case in which perforated acute appendicitis resulted in unavoidable shunt removal and subsequent fulminant papilledema requiring optic nerve sheath fenestration (ONSF) as a vision-preserving intervention. The CARE Checklist has been completed by the authors for this case report, attached as online supplementary material (for all online suppl. material, see https://doi.org/10.1159/000552023).

Case Presentation

A 17-year-old girl presented to the emergency department in November 2024 with several days of progressively worsening headache, nausea, and blurred vision. Her medical history was significant for an arachnoid cyst diagnosed in early childhood, for which a VP shunt had been placed at the age of two. The shunt had remained functional without revision, and she had been neurologically and visually stable for many years.

At presentation, best-corrected visual acuity (VA) was 20/20 in both eyes. Pupillary light reflexes and colour vision assessed by Ishihara plates were normal. Funduscopic examination revealed bilaterally elevated and blurred optic disc margins with peripapillary splinter haemorrhages, raising concern for raised ICP. Brain magnetic resonance imaging demonstrated enlargement of the perioptic subarachnoid spaces, more pronounced on the left, posterior scleral flattening (Fig. 1). Plain radiographs demonstrated the VP and LP shunt systems in situ, confirming catheter course and abdominal termination (Fig. 2). Lumbar puncture revealed a markedly elevated opening pressure of 106 cm H₂O. This value was rechecked and confirmed from the original neurosurgical records and was measured in the lateral decubitus position under standard lumbar puncture conditions. Although markedly higher than typical IIH ranges, pressures exceeding 40 cm H₂O are considered severely elevated and are relatively rare. In this long-term shunt-dependent patient, the extreme elevation was interpreted as severe secondary IIH related to altered CSF dynamics rather than acute mechanical shunt failure, as imaging confirmed shunt continuity without obstruction and hydrocephalus was absent. Automated perimetry (Humphrey Field Analyzer II-750i, Carl Zeiss Meditec AG, Germany) showed enlargement of the physiological blind spot in the right eye, with a normal visual field in the left.

Fig. 1.

T2-weighted magnetic resonance images of the brain and orbits. a Coronal section demonstrating the target sign around the optic nerves, indicating distension of the perioptic subarachnoid space. b Axial section showing enlargement of the perioptic CSF space with increased optic nerve sheath diameter and associated posterior scleral flattening, consistent with raised ICP.

Fig. 2.

Plain radiographs demonstrating the course of the VP shunt. a Lateral skull radiograph showing the proximal intracranial portion of the VP shunt catheter. b Abdominal radiograph demonstrating the distal peritoneal segment of the shunt catheter within the abdominal cavity.

Acetazolamide was initiated at a dose of 250 mg four times daily, and an additional LP shunt was subsequently placed. The patient was discharged on a tapering acetazolamide regimen. At follow-up visits over the subsequent 2 months, optic disc swelling gradually resolved, and retinal nerve fibre layer (RNFL) thickness stabilised at 133 µm bilaterally. Although substantially improved, an RNFL value of 133 µm likely represented mild residual thickening rather than complete normalisation.

Nine months later, the patient re-presented with acute abdominal pain, fever, and vomiting. Computed tomography confirmed perforated acute appendicitis, and she underwent emergent appendectomy. Owing to the contaminated peritoneal field and the risk of ascending intracranial infection, both the VP and LP shunts were removed. Ten days after shunt removal, ophthalmic examination revealed preserved VA and colour vision; however, bilateral Frisén grade 2–3 papilledema had developed. Swept-source optical coherence tomography (DRI OCT Triton, Topcon Corporation, Tokyo, Japan) demonstrated renewed RNFL thickening, measuring 303 µm in the right eye and 307 µm in the left. Visual field testing remained normal in the right eye, while a newly enlarged blind spot was observed in the left eye. Acetazolamide was restarted and escalated to 250 mg four times daily following the onset of pulsatile tinnitus and severe headaches.

Despite maximal tolerated medical therapy, papilledema continued to progress over the ensuing weeks. Two months after shunt removal, VA had declined to 20/25 in the right eye and 20/30 in the left. The left pupil demonstrated a reduced light response, without a relative afferent pupillary defect, and colour vision was mildly reduced in the left eye. Funduscopic examination showed persistent bilateral optic papilledema with splinter haemorrhages, while OCT-derived RNFL measurements became unreliable due to severe disc swelling (Fig. 3a). Visual field testing revealed bilateral enlargement of the blind spots with associated peripheral scotomata. Reinstitution of CSF diversion was discussed in a multidisciplinary setting involving neurosurgery and general surgery. Early reimplantation of a VP or LP shunt was considered unsafe because of recent peritoneal contamination and the post-operative inflammatory state. Temporary external CSF diversion was also evaluated; however, in the absence of hydrocephalus and given ongoing infection concerns, it was not pursued. Given the progressive visual deterioration, the patient’s young age, and the absence of a feasible CSF diversion strategy as determined by neurosurgery, ONSF was recommended as a vision-preserving intervention.

Fig. 3.

a Colour fundus photograph obtained after removal of the VP and LP shunts, showing marked bilateral papilledema with hyperaemic and elevated optic discs and blurred disc margins. b Follow-up fundus photograph after ONSF, demonstrating substantial regression of papilledema with improved disc contour and resolution of papilledema-related changes.

Bilateral ONSF was performed via a medial conjunctivoplasty approach. Intraoperatively, a brisk egress of CSF from both optic nerve sheaths was observed, confirming markedly elevated perioptic pressure. In the early post-operative period, best-corrected VA returned to 20/20 in both eyes. Pupillary responses, colour vision, and visual fields normalised, and funduscopic examination demonstrated substantial regression of papilledema (Fig. 3b). At post-operative month 3, automated perimetry (Humphrey 30-2 SITA-Fast) demonstrated a mean deviation of −3.12 dB (p < 1%) and a pattern standard deviation of 2.80 dB (p < 5%) in the right eye, and an mean deviation of −4.11 dB (p < 1%) with a pattern standard deviation of 2.48 dB (p < 5%) in the left eye. Final RNFL measurements at post-operative month 3 were 163 µm in the right eye and 123 µm in the left eye. Although delayed shunt reimplantation was planned after resolution of abdominal inflammation, subsequent VP reinsertion was further postponed due to an active fungal infection of the scalp at the intended surgical site, posing additional risk for device-related infection. The chronological clinical course of the patient is summarised in Table 1.

Table 1.

Clinical timeline of the case

Time	Clinical event	Intervention	Outcome
Age 2	Diagnosis of arachnoid cyst	VP shunt placement	Long-term neurological and visual stability
Age 17	Progressive headache, nausea, blurred vision; lumbar puncture opening pressure 106 cm H2O	Acetazolamide initiated (250 mg QID); LP shunt placement	Gradual resolution of papilledema
2-month follow-up	Ophthalmic reassessment	Continued medical therapy	RNFL stabilised at 133 µm OU
9 months later	Acute perforated appendicitis	Emergent appendectomy; removal of VP and LP shunts	Loss of CSF diversion
10 days post-shunt removal	Frisén grade 2–3 papilledema; RNFL 303 µm OD/307 µm OS	Acetazolamide restarted and escalated	Progressive disc oedema
2 months post-shunt removal	Progressive visual decline	Bilateral ONSF	Immediate visual improvement
Early post-operative period	Post-ONSF evaluation	—	VA 20/20 OU; regression of papilledema
Post-operative month 3	Follow-up evaluation	—	Stable vision; RNFL 163 µm OD/123 µm OS

VP, ventriculoperitoneal; LP, lumboperitoneal shunt; QID, quatre in die (four times daily); RNFL, retinal nerve fibre layer; OU, oculus uterque (both eyes); CSF, cerebrospinal fluid; OD, oculus dexter (right eye); OS, oculus sinister (left eye); ONSF, optic nerve sheath fenestration; VA, visual acuity.

Discussion

Pseudotumor cerebri is characterised by signs and symptoms of raised ICP, most notably papilledema, in the absence of an intracranial mass, hydrocephalus, or central nervous system infection [1]. Although often used interchangeably with IIH, the pseudotumor cerebri phenotype may also arise from secondary disturbances of CSF dynamics, including structural abnormalities and prior neurosurgical interventions [2].

The present case illustrates a secondary pseudotumor cerebri syndrome related to a childhood arachnoid cyst requiring long-term CSF diversion. VP shunting provided durable ICP control for nearly 14 years. There was no recurrence while both VP and LP shunts were in place; papilledema developed only after removal of both systems due to perforated appendicitis. The initial recurrence that occurred 15 years after VP shunt placement resolved following addition of the LP shunt, and the patient remained clinically stable for approximately 9 months prior to the appendicitis episode.

Management aims to reduce ICP and preserve visual function. Acetazolamide remains first-line therapy, while surgical intervention is indicated when papilledema progresses or visual function deteriorates despite maximal medical therapy [3, 4]. CSF diversion procedures (VP/LP shunts) are widely used for sustained ICP reduction. ONSF is primarily used for vision-threatening papilledema, providing local decompression of the optic nerve head without altering global ICP. As previously stated, ONSF does not normalise global ICP; therefore, continued neurological follow-up and definitive CSF diversion planning remain essential despite ophthalmic improvement.

In this patient, the long-standing equilibrium achieved through dual CSF diversion was abruptly disrupted by perforated acute appendicitis. Because VP and LP shunts establish a conduit between the central nervous system and the peritoneal cavity, intra-abdominal sepsis poses a substantial risk of retrograde infection, including meningitis or ventriculitis [5–7]. Perforated appendicitis therefore represents a compelling indication for urgent shunt externalisation or removal. Although broad-spectrum intravenous antibiotics are initiated promptly, perforation with peritoneal contamination substantially increases the risk of ascending shunt infection, and shunt externalisation or removal is frequently recommended to prevent life-threatening intracranial infection. Had the appendicitis been non-perforated, shunt removal might not have been mandatory, and close observation under broad-spectrum intravenous antibiotic therapy could have been considered.

Shunt-related complications remain common over the lifetime of implantation, with paediatric series reporting high cumulative revision rates within the first decade [8, 9]. Appendicitis in VP-shunted patients is often diagnosed late and may present after perforation, increasing the likelihood of shunt intervention and the risk of ICP decompensation [10–12]. In the present case, removal of both VP and LP shunts led to rapid ICP elevation and fulminant papilledema refractory to maximal medical therapy. Reinstitution of CSF diversion was discussed in a multidisciplinary setting. Early reimplantation was considered unsafe because of recent peritoneal contamination and post-operative inflammatory state. Temporary external CSF diversion was also evaluated but not pursued due to the absence of hydrocephalus and ongoing infection concerns. Although delayed shunt reimplantation was planned after resolution of abdominal inflammation, subsequent VP reinsertion was further postponed due to an active fungal infection of the scalp at the intended surgical site. Consequently, no immediate CSF diversion strategy was feasible at that stage. Under these circumstances, urgent bilateral ONSF represented the only viable vision-preserving strategy, with rapid post-operative regression of papilledema and restoration of visual function.

In conclusion, abrupt loss of long-standing CSF diversion during intra-abdominal sepsis can precipitate rapid ICP decompensation and severe visual compromise. Although shunt removal may be essential to prevent ascending infection in the setting of peritoneal contamination, it may leave shunt-dependent patients vulnerable to fulminant papilledema; early ophthalmic recognition and multidisciplinary coordination are therefore critical.

Acknowledgment

This case report was prepared in accordance with the CARE reporting guidelines. The completed CARE checklist is provided as online supplementary material.

Statement of Ethics

Ethical approval is not required for this case report in accordance with local and national guidelines. Written informed consent was obtained from the patient’s legal guardian for publication of this case report and any accompanying images.

Conflict of Interest Statement

The authors declare that they have no conflicts of interest.

Funding Sources

This study received no specific funding.

Author Contributions

S. Gedik contributed to the conception and design of the study, participated in the patient’s clinical follow-up, and critically revised the manuscript for important intellectual content. R.N. Karakaya participated in the patient’s clinical follow-up, contributed to data acquisition, analysis, and interpretation, and drafted the manuscript. O. Ocal participated in the patient’s clinical follow-up and contributed to data acquisition and literature review. H.D. Ilhan participated in the patient’s clinical follow-up, was involved in the surgical management including optic nerve sheath fenestration, and contributed to data analysis and manuscript editing. M.S. Kazan participated in the patient’s clinical follow-up, was involved in the surgical management including lumboperitoneal and ventriculoperitoneal shunt procedures, and contributed to data acquisition. All authors contributed to the conception, clinical management, data collection, analysis, and writing of the manuscript, and approved the final version of the manuscript.

Funding Statement

This study received no specific funding.

Data Availability Statement

All data generated or analysed during this study are included in this published article. Any further enquiries regarding the data may be directed to the corresponding author.