Primary spinal extradural hydatid cyst: a rare cause of compressive neuropathy in a pediatric patient

Abstract

Introduction:

Hydatid illness is caused by the parasite tapeworm Echinococcus. Spinal hydatid disease without visceral involvement is a rare condition. Symptoms of spinal hydatid disease are not specific and typically stem from spinal cord compression. Back pain is common, while radicular pain is observed in 25% to 95% of patients. Paraparesis is noted in 25% to 77% of individuals.

Case presentation:

We present a case of an isolated spinal hydatid cyst in the lumbar spine in a 13-year-old girl presented with progressive bilateral lower limb paraparesis. The radiological, laboratory, and clinical findings were consistent with a diagnosis of brucellosis. However, the symptoms persisted despite treatment, and it was later revealed through surgery and pathological examination that the child had isolated hydatid cysts in the vertebrae.

Discussion:

While primary spinal hydatid cysts are rare, the incidence of these lesions might be higher if cases that resembled other cystic lesions on radiological scans but were conservatively managed, especially in endemic regions, are considered. When determining a surgical approach, it is important to consider hydatid disease as a possibility for certain bone cystic lesions.

Conclusion:

Hydatid cysts should be considered in any child with a history of paralysis, especially if the child comes from an endemic area. In our case, the child was initially diagnosed with brucellosis, but it was later found that isolated hydatid cysts in the vertebrae caused the paralysis.

Introduction

Hydatid is a Greek term that translates as “watery cyst.” Hydatid illness is caused by the parasite tapeworm Echinococcus (E. granulosus and, less commonly, E. multilocularis)^[1]. The most prevalent locations of infection are the liver (75%), lung (15%), brain (2–4%), and genitourinary tract (2–3%)^[1]. Only 0.5–3.1% of individuals get bone involvement, half of which occurs in the spine^[2]. Hydatid disease of the bone most commonly affects the spine. Spinal hydatid cysts make up 1% of all instances of hydatid illness^[3]. Spinal hydatid disease without visceral involvement is a rare condition^[2].

Unfortunately, the diagnosis is frequently accidental, and unusual settlements may go unnoticed, resulting in increased morbidity and mortality^[4]. In addition, there are differing viewpoints about therapy and follow-up, and there is still no universal consensus on this subject^[5,6].

We present a case of an isolated spinal hydatid cyst in the lumbar spine with neurological symptoms.

Case presentation

A 13-year-old female was referred to our medical institution exhibiting progressive bilateral lower limb paraparesis. Four months antecedent to presentation, she manifested lower lumbar pain concomitant with fever and headache, prompting consultation with a general internist. Brucellosis was diagnosed, leading to an unspecified 10-day treatment course that the family did not adhere to. Seeking resolution for ongoing lumbar discomfort, the patient sought the expertise of an orthopedic practitioner, leading to the identification of vertebral compression fracture at the T12-L1 level via computed tomography (CT) imaging. Concurrently, due to persistent fever, a Wright test was requisitioned, revealing a titer of 1/320 indicative of Maltese infection. Subsequently, the patient underwent treatment with rifampicin and Bactrim. After the course of treatment, Wright was retested and the result was negative, so the patient was transferred to our facility for paraparesis evaluation. Clinical neurologic examination revealed a Glasgow Coma Scale score of 15/15, absence of cranial nerve deficits, and normal upper limb strength, tone, and reflexes. However, scrutiny of the lower limbs unveiled 1/5 strength in hip and knee flexion and extension bilaterally, 2/5 in the left ankle and fingers, and 3/5 in the right one. Additional findings included hypotonia, hyporeflexia, and normative bilateral plantar reflex. Sensory paresthesia extended to the inguinal ligament, unaccompanied by sphincter involvement, alongside an unexplained elevation in body temperature.

Based on the CT scan and clinical findings, a vertebral collapse at the L1 level was disclosed, prompting the decision for surgical intervention (Fig. 1). Doctors thought the CT findings go with the diagnosis of Maltese infection. During the abdominal position surgery, a radiographic determination of the first vertebra’s level was made, and the layers were opened from T11 to L3. Spinal fusion was performed using eight screws at T11-12 and L2-3. Notably, an extrameningeal cyst within the spinal canal at L1, exerting pressure on the meninges, was discovered and excised. Histopathological analysis revealed an acellular hyalinized laminated wall consistent with a hydatid (echinococcus) cyst (Fig. 2). Postoperatively, the patient’s condition was stable with normal vital signs. Treatment included albendazole 400 mg daily for 9 weeks, with 1-week intervals between every 3 weeks, alongside a prescribed physical therapy regimen.

Figure 1.

CT scan relieved a vertebral collapse at the L1 level.

Figure 2.

Diagrammatic representation of the three layers of hydatid cyst. Black arrow endocyst: comprising the germinal membrane along with protoscolices; blue arrow exocyst: comprising lamellated eosinophilic acellular avascular structures; orange arrow: pericyst: fibrocellular tissue.

A follow-up month revealed a 40% decrease in the first lumbar vertebra’s body height, accompanied by inconsistent signs and the recurrence of cysts on both sides, varying in size, with the largest measuring 2.2 cm.

Discussion

Hydatid cyst disease is an infectious condition transmitted to humans through the ingestion of contaminated food containing Echinococcus granulosus eggs. This disease is prevalent in regions such as Asia, the Mediterranean (including Syria), and South America^[7].

Hydatid disease primarily affecting the spine, without accompanying systemic symptoms, can occur when larvae from hydatid cysts are carried through the portovertebral venous system into the epidural space of the vertebral canal. As the cysts gradually enlarge, they cause bone destruction and spread into the epidural space, leading to compression of nerves and resulting neurological symptoms. Unlike secondary epidural hydatidosis, instances where there’s no apparent involvement of the vertebral column on radiological scans are extremely rare. Alternatively, spinal involvement may stem from the direct spread of hydatid cysts originating from the lungs, abdomen, or pelvis^[7].

Symptoms of spinal hydatid disease are not specific and typically stem from spinal cord compression. Back pain is common, occurring in 85% of cases, while radicular pain is observed in 25% to 95% of patients. Paraparesis is noted in 25% to 77% of individuals. Additionally, occurrences of urinary retention, sciatica, and paraplegia have been documented^[8].

The most effective treatment for curing this disease involves surgery, where the cyst is completely removed without any rupture, ensuring the integrity of the cyst wall is maintained. Laminectomy is typically the preferred surgical approach to alleviate the compression caused by the cysts. The focus during surgery should be on completely removing the cysts without causing any rupture. Even if the surgical removal is successful, it’s advisable to complement it with anthelminthic therapy as an additional measure^[9].

Primary spinal intradural extramedullary hydatid cyst disease including our case is extremely rare^[8].

Magnetic resonance imaging (MRI) is considered the primary diagnostic tool for identifying spinal hydatid cysts. Key MRI findings include a cyst wall appearing hypointense on both T1- and T2-weighted images, along with a uniformly hyperintense cyst content specifically on T2-weighted images. Nonetheless, confirmation of the diagnosis typically relies on histopathological examination of the excised tissue^[9].

Recurrence presents a significant challenge in spinal hydatidosis, with reported rates ranging from 30% to 100%. Due to this high recurrence rate, the prognosis for spinal hydatidosis is unfavorable, often likened to that of spinal malignancies. We stress the importance of using MRI for both diagnosis and ongoing monitoring to detect any residual or recurring lesions. The poor prognosis may be attributed to the localization of the cysts (intradural versus extradural), as the penetration of albendazole, an anthelminthic drug, into the intradural space is limited due to passive diffusion transport mechanisms^[3].

Comparing our case with those reported in the literature, we find that radiographic imaging may be misleading in some instances, as in our case neuroimaging revealed the identification of vertebral compression fracture at the T12-L1 level, and therefore cannot be solely relied upon. Doubt should be cast upon such diagnoses based on the region. Our patient hails from an area dependent on sheep grazing, and we observed recurrence post-surgery, which is disappointing given the difficulty of repeating surgical interventions. The pivotal question we aim to address through this research is: what is the optimal surgical approach in such cases to minimize the likelihood of recurrence.

While primary spinal hydatid cysts are rare, the incidence of these lesions might be higher if cases that resembled other cystic lesions on radiological scans but were conservatively managed, especially in endemic regions, are considered. When determining a surgical approach, it’s important to consider hydatid disease as a possibility for certain bone cystic lesions. The work has been reported in line with the SCARE 2023 criteria^[10].

Key clinical message

Hydatid cysts should be considered in any child presenting with a history of paralysis, especially if they come from an endemic area. Reaching a diagnosis should not prevent us from continuing investigations, given the possibility of coexisting diseases that share the same clinical symptoms. In our case, the child was initially diagnosed with brucellosis, but it was later found that the cause of the paralysis was isolated hydatid cysts in the vertebrae.

Ethical approval

Not applicable.

Consent

Written informed consent was obtained from the patient's parents/legal guardian for publication and any accompanying images. A copy of the written consent form is available for review by the editor-in-chief of this journal upon request.

Sources of funding

All the authors declare to have received no financial support or sponsorship for this study.

Author’s contribution

MA, JZ contributed to drafting, reviewing, editing, and approving the final manuscript; AA, Mh, SH contributed to drafting, editing, and approving the final manuscript; GB contributed to drafting, reviewing, editing, corresponding, and approving the final manuscript; EA, MA contributed to reviewing, supervising, and approving the final manuscript; GH, MS supervision.

Conflicts of interest disclosure

All the authors declare to have no conflicts of interest relevant to this study.

Research registration unique identifying number (UIN)

Not applicable.

Guarantor

Sultaneh Haddad.

Provenance and peer review

Not commissioned, externally peer-reviewed.

Data availability statement

Not applicable.