Surgical Management of Multiple Cerebral Hydatid Cysts without Systemic Involvement: A Case Report

Abstract

Hydatidosis is a rare and serious parasitic disease caused by Echinococcus granulosus larvae, with central nervous system (CNS) involvement being a potentially fatal complication. We present a case of neurohydatidosis in a 55-year-old male farmer exhibiting symptoms of the left parietal syndrome. Imaging studies revealed six well-defined, non-enhancing cystic lesions in the left parietal lobe, and serological evaluation confirmed the presence of Echinococcus-specific IgG antibodies. A chest-abdomen-pelvis CT scan showed no additional hydatid cysts in other organs.

The patient underwent microsurgical resection of all six cerebral parietal cysts without rupture, using Dowling's maneuver of hydrodissection with isotonic saline solution. Intraoperatively, the membrane of a previously ruptured seventh cyst was found and excised, and the remaining cavity was irrigated with hypertonic saline solution to prevent recurrence. The patient recovered well without any new neurological deficits or postoperative complications, and a histopathological examination confirmed the diagnosis. He was discharged with previous symptoms in remission and continued antihelminthic treatment with albendazole for 28 days.

Cerebral cystic echinococcosis should be included in the differential diagnosis for patients with multiple cystic lesions in the brain. This case report highlights the unusual presentation of multiple cerebral hydatid cysts without the involvement of other parenchymal organs. Surgical resection using hydrodissection combined with antihelminthic therapy is an effective treatment approach for neurohydatidosis.

 

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Resumo

A hidatidose é uma doença parasitária rara e grave causada pelas larvas de Echinococcus granulosus, com envolvimento do sistema nervoso central (SNC) sendo uma complicação potencialmente fatal. Apresentamos um caso de neurohidatidose em um agricultor de 55 anos que manifestava sintomas da síndrome parietal esquerda. Estudos de imagem revelaram seis lesões císticas bem definidas e não captantes no lobo parietal esquerdo, e a avaliação sorológica confirmou a presença de anticorpos IgG específicos para Echinococcus. Uma tomografia computadorizada de tórax, abdômen e pelve não mostrou cistos hidatídicos adicionais em outros órgãos.

O paciente foi submetido à ressecção microcirúrgica de todos os seis cistos parietais cerebrais sem ruptura, utilizando a manobra de Dowling para hidrodissecção com solução salina isotônica. Durante a operação, a membrana de um sétimo cisto, previamente rompido, foi encontrada e removida, e a cavidade restante foi irrigada com solução salina hipertônica para prevenir recorrência. O paciente teve uma boa recuperação, sem nenhum novo déficit neurológico ou complicações pós-operatórias, e o exame histopatológico confirmou o diagnóstico. Ele teve alta com os sintomas anteriores em remissão e continuou o tratamento anti-helmíntico com albendazol por 28 dias.

A equinococose cística cerebral deve ser incluída no diagnóstico diferencial para pacientes que apresentam múltiplas lesões císticas no cérebro. Este caso destaca a apresentação incomum de múltiplos cistos hidáticos cerebrais sem envolvimento de outros órgãos parenquimatosos. A ressecção cirúrgica usando hidrodissecção combinada com antihelmínticos é uma abordagem eficaz para neurohidatidose.

 

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Keywords

echinococcus granulosus - cerebral hydatid cysts - dowling's technique - antihelminthic therapy

Palavras-chave

echinococcus granulosus - cistos hidatídicos cerebrais - técnica de dowling - terapia anti-helmíntica

Introduction

Hydatid disease in humans is an infrequent parasitic condition resulting from the larval stages of tapeworms belonging to the Echinococcus genus, with cystic echinococcosis being the predominant manifestation. The endemic areas of this disease encompass the Mediterranean region, Australia, Africa, the Middle East, and specific regions of South America, with an annual incidence rate of 1–200 per 100.000 inhabitants.[1]

Adult Echinococcus granulosus lives in the intestines of dogs. Eggs are released through feces and are infectious. When ingested by intermediate hosts like sheep, eggs hatch in the intestine, penetrate the intestinal wall, and migrate through various organs of the body, with a particular affinity for the liver and lungs. Within these organs, eggs mature into hydatid cysts containing protoscolices and daughter cysts. Dogs become infected by consuming the organs of intermediate hosts. In humans, which are abnormal hosts, the ingestion of eggs leads to the development of hydatid cysts in various organs. If cysts rupture, protoscolices can form new cysts elsewhere in the body (secondary echinococcosis).[2]

Hydatid infections can occur in various organs. The most common is the liver, followed by the lungs and spleen. Other less common locations include the brain, spine, retroperitoneal space, kidneys, and musculoskeletal system.[3]

Neurohydatidosis accounts for 1–2% of all primary hydatid cysts. Cysts within the cranial region can be categorized as primary or secondary hydatid cysts.

Spontaneous rupture or rupture triggered by trauma or surgical intervention can occur in primary hydatid cysts. When the cyst ruptures, the larvae are released into the brain tissue, resulting in the formation of multiple secondary hydatid cysts. Another potential scenario for the development of multiple cysts is if a cyst ruptures and circulates through the left cardiac chambers, in the presence of cardiac pathology, or within the major arterial vessels, thereby facilitating the dissemination of larvae to the brain. In rare cases, multiple cerebral hydatid cysts can occur due to the ingestion of multiple larvae, which then travel through the arteries and cause embolism in the brain. These rare multiple secondary cysts are infertile, meaning they lack the necessary structures for reproduction.[1]

 

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Case Presentation

A 55-year-old male from a pastoral area, where he owns sheep and dogs, presented to the hospital with a concerning history of neurological symptoms. He reported that approximately one month before admission, he noticed subtle changes in his daily activities. He observed a gradual decline in his right-hand coordination, making it difficult for him to perform tasks such as buttoning his shirt and holding objects steadily. This decline was accompanied by agraphia; he found it increasingly challenging to write notes or even sign his name. Additionally, he experienced acalculia, leading to difficulty with simple calculations.

One week prior to admission, the patient experienced a sudden loss of consciousness and was transported to the hospital. This episode of loss of consciousness was brief but concerning, lasting several minutes, and followed by confusion and disorientation. Magnetic Resonance Imaging (MRI) revealed six distinct cystic lesions in the left parietal lobe, extending toward the lateral ventricle. These lesions appeared well-defined and non-enhancing with minimal perilesional edema ([[Fig. 1]]). The serological evaluation showed positive results for Echinococcus-specific immunoglobulin G (IgG) antibodies. However, the complete blood count did not indicate eosinophilia. A Chest-Abdomen-Pelvis Computed Tomography (CT) scan was conducted to assess the presence of hydatid cysts in other organs, but no additional cysts were detected.

Fig. 1 The MRI showing the cysts with minimal perilesional edema suggesting a possible cyst rupture.

A left parietal craniotomy was performed, followed by a C-shaped durotomy. Intraoperative ultrasound was used to locate the cysts. A minimal corticectomy was done at the posterior border of the superior parietal lobule. Subsequently, a cluster of six hydatid cysts was exposed at 1 cm subcortically. The cysts were carefully dissected and individually removed using the Dowling-Orlando technique. We used an isotonic saline solution (0.9% NaCl) for hydrodissection, which facilitates the separation of the hydatid cysts from the surrounding brain tissue without damaging the delicate cyst wall. This technique minimizes the risk of rupture during the dissection process by providing a gentle and controlled method for cyst removal. During the procedure, a previously ruptured seventh cyst membrane was discovered and exercised. The remaining cavity was flushed with a hypertonic saline solution (3% NaCl), a standard scolicidal agent used to prevent recurrence by destroying any residual protoscolices. Following this, the resection cavity and the rest of the surgical field were irrigated with an isotonic saline solution once again to ensure that any remaining debris was cleared without causing any other complications ([[Fig. 2]]).

Fig. 2 Gross appearance of the hydatid cyst in the operative field and after intact removal.

The patient recovered well without any new neurological deficits or postoperative complications. He received therapy with ceftriaxone, levetiracetam, dexamethasone, and albendazole. Ceftriaxone was administered at a dose of 2 g intravenously once daily, starting 60 minutes prior to surgery and continued for the next 48 hours postoperatively until the removal of the epicranial drain. This was done as a prophylactic measure to minimize the risk of infection due to potential contamination during surgery. Levetiracetam was initiated at a dose of 500 mg twice daily (total 1000 mg/day) upon admission due to the patient's sudden loss of consciousness, which raised concerns about potential seizures. This treatment continued throughout the postoperative period for 3 weeks to prevent any seizure activity, considering the brain manipulation during surgery and the patient's neurological history. Dexamethasone was given at a dose of 4 mg intravenously every 6 hours for 5 days, followed by a taper over the next 5 days. This medication was initiated upon admission to manage cerebral edema and inflammation associated with hydatidosis and the surgical procedure. Lastly, albendazole was initiated on the day of surgery and administered at a dose of 400 mg orally twice daily (total 800 mg/day) for 28 days, with the patient being monitored for response to treatment in the infectious disease department. Albendazole is a standard antiparasitic treatment for hydatid cysts that is intended to prevent recurrence and eliminate any residual parasitic material.

Histopathological examination confirmed the diagnosis of hydatid cysts. Postoperative computed tomography showed complete removal of the hydatid cysts ([[Fig. 3]]). The patient was discharged on postoperative day 10, and parietal syndrome symptoms were in remission.

Fig. 3 The postoperative CT scan showing the complete removal of the hydatid cyst.

 

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Discussion

Hydatidosis is a rare parasitic disease with potentially fatal complications.[1] [2]

Serological tests, such as ELISA or immunoblot assays detect immunoglobulin G antibodies against specific antigens of Echinococcus species. These tests are used to diagnose and monitor cases of echinococcosis.[4] Notably, in our case, while serology showed positive IgG antibodies for Echinococcus, there was an absence of peripheral eosinophilia, which is consistent with reports that eosinophilia is not always present in cerebral hydatidosis cases. Interestingly, the literature suggests that eosinophilia is more commonly associated with complicated cystic echinococcosis,[5] which could explain its absence in uncomplicated cerebral cases, as in our case.

Imaging studies, such as ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI), are valuable for visualizing hydatid cysts in various organs. These imaging techniques can help identify cyst location, size, and number.

CT scans generally show hydatid cysts as well-defined, circular or oval lesions with smooth walls that appear hypodense due to fluid content, similar to cerebrospinal fluid. In cases where the cysts are infected, fluid-fluid levels or gas bubbles may be visible. Edema and mass effects can occur around the cysts, particularly if they exert pressure on surrounding brain tissue.[6]

Hydatid cysts are primarily concentrated within the watershed zone of the middle cerebral artery. MRI displays cystic structures that exhibit a distinct and well-defined appearance. These cysts are notably non-enhancing, indicating a lack of increased contrast uptake in the imaging, and contain fluid that appears in isointense to cerebrospinal fluid across all pulse sequences. Notably, there is an absence of calcification or surrounding edema in the usual course, although the existence of perilesional edema may suggest complications like rupture or secondary infection.[7]

Fine Needle Aspiration may be performed to obtain a sample of cyst fluid for analysis, particularly in organs outside the brain. Microscopic examination of the fluid can reveal characteristic structures such as protoscolices or hooklets, which help confirm hydatid disease. In some cases, if the fluid analysis is inconclusive or additional information is required, a biopsy of the cyst wall or the affected organ may be needed for definitive diagnosis.[8]

Hydatid cysts have three main components: the laminated layer, germinal layer, and cyst wall. The laminated layer is a dense outer layer that protects the cyst. The germinal layer is where the parasite grows and produces protoscolices and daughter cysts. The cyst wall consists of host tissue and often shows signs of chronic inflammation. Protoscolices are infective structures within the cyst fluid, while daughter cysts are smaller cysts formed within the germinal layer. The host's immune response leads to inflammation and the formation of granulomas.[9]

The differential diagnosis of hydatid cysts encompasses various conditions that share similarities in imaging characteristics. These include pyogenic or fungal abscesses, which are infectious collections; cystic granulomas indicating inflammatory responses; cystic astrocytoma, a type of primary brain tumor presenting with cystic components; arachnoid cysts originating from the arachnoid membrane; and porencephalic cysts associated with localized brain tissue loss. Discerning these conditions is crucial for accurate diagnosis and appropriate management.[10] [11]

Hydatidosis management strategies involve a diverse array of therapeutic choices tailored to the specific characteristics and location of the cyst and the patient's condition. Surgical resection, which involves complete cyst removal, is a fundamental treatment option. Another technique, known as PAIR (puncture, aspiration, injection of protoscolicidal agent, and respiration), involves a series of steps to puncture the cyst, aspirate its contents, inject a protoscolicidal agent to neutralize any remaining larvae, and then aspirate. Anti-helminthic agents like albendazole and mebendazole work to eradicate larvae and reduce cyst size. This approach is crucial in cases where surgical options may be limited or as a complementary treatment to minimize the risk of recurrence. In cases in which the cysts are inactive and asymptomatic, a watchful waiting approach is adopted, involving regular monitoring to assess any changes in the cyst's status.[12]

The management of cerebral hydatid cysts typically requires surgical intervention. The preferred approach is Dowling's maneuver, which involves careful infusion of warm saline to safely and separate the cyst from the brain, minimizing the risk of rupture. If complete removal without rupture is challenging, an alternative approach involves puncturing the cyst and aspirating its contents before removal.[13] [14]

The choice of surgical technique depends on the specific characteristics of the cyst and the assessment of the surgical team.

The Dowling technique is a highly effective surgical method for removing cerebral hydatid cysts without causing rupture. It was described by Dowling in 1929, before the introduction of microscopes in neurosurgery. Magnification is recommended during the early stages of surgery to avoid damaging the fragile cyst wall and to establish a precise surgical plane. A saline solution serves a dual purpose in the surgical procedure, facilitating the dissection of the cyst wall from surrounding brain tissue and aiding in the subsequent extraction of the hydatid. This irrigating solution not only assists in maintaining tissue integrity but also contributes to a smoother and more controlled removal process. Tilting the operation table toward the lesion site and lowering the patient's head helps in the gravity-assisted removal of the cyst.[15]

In our case, the use of the Dowling-Orlando technique was highly effective for safely removing multiple cerebral hydatid cysts. Given the proximity of the cysts to the lateral ventricle and their subcortical location, the precise hydrodissection approach, using isotonic saline, minimized rupture risk and facilitated separation from the surrounding brain tissue. This step is particularly crucial in cerebral hydatidosis because rupture can lead to serious complications, including infection, recurrence, or systemic allergic reactions.[16]

Furthermore, the presence of a ruptured seventh cyst necessitated the use of hypertonic saline as a scolicidal agent in the residual cavity to effectively reduce the risk of recurrence by eliminating any remaining protoscolices. This application, supported by literature as having a relatively safe, non-toxic profile for neural tissue and being an effective scolicidal agent in neurosurgical cases of hydatidosis,[16] [17] [18] was integral to the treatment strategy.

Hydatid cysts are delicate and easily prone to rupture. The primary goal of curative treatment is to meticulously remove the intact cysts, emphasizing the avoidance of any unintended spillage. In the event of rupture, the surgical procedure necessitates meticulous suctioning of the cyst contents and subsequent irrigation of the cavity with a hypertonic saline solution to prevent recurrence and eliminate any residual parasitic material.[17] [18] It is crucial to acknowledge that hydatid cyst rupture not only increases the risk of local complications and recurrence but also elevates the potential for systemic reactions, such as anaphylaxis. Therefore, surgeons must be vigilant, employing preventive strategies to avoid rupture and being prepared to manage anaphylactic reactions promptly.[19]

Specifically, cyst aspiration is a common procedure for brainstem lesions, with the preference against Dowling's technique due to associated higher morbidity rates. For asymptomatic and deeply situated lesions, medical treatment may be considered. However, when surgically removing large cysts, a gradual approach is essential to mitigate the risk of rapid decompression syndrome. This approach entails a careful and deliberate process to minimize potential complications associated with rapid decompression during surgery.[20]

 

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Conclusion

Hydatidosis is an infrequent parasitic disease that poses the potential for severe complications. The presence of multiple cerebral hydatid cysts without involvement of other organs is uncommon. Early diagnosis and timely treatment are essential for a favorable outcome. The primary objective of surgery is meticulous and complete removal of the intact cysts. Postoperatively, a comprehensive treatment regimen entails the administration of antibiotics and antihelminthic medications, strategically implemented to forestall recurrence and promote a successful recovery.

 

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Conflict of Interest

The authors report no conflict of interest.

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Publikationsverlauf

Eingereicht: 24. November 2023

Angenommen: 20. März 2025

Artikel online veröffentlicht:
07. Juli 2025