Echinococcosis

Hydatid disease of central nervous system, a clinicopathological study of 33 cases

Objectives

Involvement of central nervous system (CNS) by Hydatid cyst is rare comprising 0.5-4% of all hydatid cysts and principally affecting those younger than 20 years, giving rise to cystic masses mostly in the cerebral hemispheres. To report the clinicopathological findings of CNS hydatid cysts, we diagnosed and review the findings of the previous studies.

Materials and Methods

All cases reported in our Section between January 1, 2001, and June 30, 2022, were included in the study. By searching our files, cases were retrieved, and diagnosis was confirmed. Follow-up was received on telephone. Ethical exemption was obtained.

Results

Thirty-three cases were diagnosed. Almost all were received from rural areas. There were 17 females and 16 males. Mean and median age were 20 and 19 years, respectively. Over 60% were younger than 20 years of age. All 33 involved the cerebral and cerebellar hemispheres. Seventy six percent were supratentorial while 24% were infratentorial. The most common signs and symptoms included weakness, headaches, and seizures. All appeared as solitary cystic masses on imaging. Almost 67% were clinically suspected to be hydatid cysts. Grossly, thin-walled transparent unilocular or multilocular cysts filled with viscous material were received intact in 52% and in multiple pieces in 48% cases. Intact cysts measured 7 cm on average. All demonstrated typical histology. Of the nine patients whose follow-up was available, one died from unspecified acute surgery related complications. Four patients were asymptomatic at the time of follow-up, whereas four developed recurrent cysts. All eight received albendazole therapy.

Conclusion

Cerebellum/posterior fossa location was common. Several cases were received in multiple pieces with increased risk of recurrence. Clinicopathological features were similar to those reported in literature. This series will hopefully serve to increase awareness regarding CNS hydatid disease.

Hydatid disease of the brain and spine

Hydatid disease of the central nervous system is relatively rare and comprises about 2-3% of all the hydatid cyst cases reported in the world. Spinal hydatid disease is an even rarer entity. It is endemic in sheep and cattle-raising regions, seen mainly in Mediterranean countries including Turkey and Syria. Pediatric neurosurgeons in non-endemic countries face a challenge when they encounter children with hydatid cysts of the central nervous system, mostly due to lack of awareness and the ensuing diagnostic dilemmas. It is also a significant socioeconomic problem in developing countries, due to improper hygiene and lack of dedicated veterinary practice. The clinical features are largely nonspecific and very according to location and severity of disease. However, with the advent of advances in MR imaging, the diagnostic accuracy of hydatic disease involving the brain and spine has increased. Intact removal of the cyst/s, without causing any spillage, and appropriate antihelminthic therapy is the goal and key to cure and prevention of recurrence. In this manuscript, the current literature on hydatid cyst of the brain and spine is reviewed to better understand the epidemiology, pathophysiology, diagnostic accuracy, and advances in therapeutic options. A heightened clinical suspicion, awareness of MR imaging features, improved surgical strategies, and options for prevention are discussed.

Echinococcus multilocularis Calreticulin Interferes with C1q-Mediated Complement Activation

As a zoonotic disease caused by Echinococcus multilocularis larvae, alveolar echinococcosis (AE) is one of the most severe forms of parasitic infection. Over a long evolutional process E. multilocularis has developed complex strategies to escape host immune attack and survive within a host. However, the mechanisms underlying immune evasion remain unclear. Here we investigated the binding activity of E. multilocularis calreticulin (EmCRT), a highly conserved Ca²⁺-binding protein, to human complement C1q and its ability to inhibit classical complement activation. ELISA, Far Western blotting and immunoprecipitation results demonstrated that both recombinant and natural EmCRTs bound to human C1q, and the interaction of recombinant EmCRT (rEmCRT) inhibited C1q binding to IgM. Consequently, rEmCRT inhibited classical complement activation manifested as decreasing C4/C3 depositions and antibody-sensitized cell lysis. Moreover, rEmCRT binding to C1q suppressed C1q binding to human mast cell, HMC-1, resulting in reduced C1q-induced mast cell chemotaxis. According to these results, E. multilocularis expresses EmCRT to interfere with C1q-mediated complement activation and C1q-dependent non-complement activation of immune cells, possibly as an immune evasion strategy of the parasite in the host.

Glycans in the roles of parasitological diagnosis and host-parasite interplay

The investigation of the glycan repertoire of several organisms has revealed a wide variation in terms of structures and abundance of glycan moieties. Among the parasites, it is possible to observe different sets of glycoconjugates across taxa and developmental stages within a species. The presence of distinct glycoconjugates throughout the life cycle of a parasite could relate to the ability of that organism to adapt and survive in different hosts and environments. Carbohydrates on the surface, and in excretory-secretory products of parasites, play essential roles in host-parasite interactions. Carbohydrate portions of complex molecules of parasites stimulate and modulate host immune responses, mainly through interactions with specific receptors on the surface of dendritic cells, leading to the generation of a pattern of response that may benefit parasite survival. Available data reviewed here also show the frequent aspect of parasite immunomodulation of mammalian responses through specific glycan interactions, which ultimately makes these molecules promising in the fields of diagnostics and vaccinology.

Peripontomedullary hydatid cyst: Case report and literature review

INTRODUCTION

Hydatid cyst represents the parasitic infection by Genus Echenococcus Granulosis. This disease usually involves liver followed by lungs and rarely the CNS. The CNS involvement by the Hydatid Cyst is present in 1-2% of all hydatidosis. Even when it is found in the Brain it presents usually in the supratentorial compartment. However this case was unique in having the Hydatid cyst within the infratentorial fossa. With multiple small cysts, causing mass effect and challenging for surgical resection.

PRESENTATION

A 44 years female presented with headache, diplobia and bulbar symptoms, followed by ataxia. Full examination, proper investigations showed the peripontomedullary hydatid cysts. Surgical management is illustrated.

DISCUSSION

It is still challenging for the neurosurgeons to operate on these lesions in spite of modern technologies and fancy approaches due to its delicate nature, associated risk of allergic reaction, cyst's material dissemination and irreversible injury of multiple neurological structure due to prolonged compression of cranial nerves crossing the cerebellopontine angle.

CONCLUSION

In this case report we are presenting a rare case of Multiple Hydatid cysts involving a rare location in the brain; peripontomedullary area and extending all the way down to the foramen magnum. Supported with a literature review in relation to disease etiology, epidemiology, clinical presentation and management.

Cured Transudative Pleural Effusion: A Case Report

Echinococcosis or hydatid disease is a helminthic infection caused by larvae of tapeworm Echinococcus granulosus. While the cysts can involve all organs, liver is the most common site of infection and the lungs are the second most commonly involved organ in young adults. In addition to endemic areas its incidence is growing all around the world due to the ease of transcontinental travel. Disease presentation varies and usually is due to mass effect or dysfunction of the involved organ and surgical resection is the recommended treatment. Here we present the case of a young man with primary pulmonary echinococcosis with involvement of the entire right lung.

Immunodiagnosis of CNS parasitic infections

The nature of many parasitic infections of the central nervous system (CNS) requires immunodiagnosis to confirm presumptive diagnoses. The CNS is the primary site of parasite infection for some parasitic organisms and for others, neurological infection occurs only in immunocompromised hosts. Still other parasites cause ectopic infections of the CNS and occur very rarely. This review concentrates on laboratory diagnosis of diseases that are caused by parasites with a primary predilection for the CNS. Emphasis is placed on laboratory diagnostic methods that are used and suitable for clinical diagnosis, rather than a comprehensive review of all the experimental methods that have been reported in the literature. Immunodiagnosis is not appropriate for the diagnosis of all parasitic infections of the CNS; in those cases, alternative diagnostic methods are presented, but not discussed in detail. In some instances potential new antigens or methods are presented, particularly if adoption of these methods is expected in the near future.

Pathology of CNS parasitic infections

Parasitic infections of the central nervous system (CNS) include two broad categories of infectious organisms: single-celled protozoa and multicellular metazoa. The protozoal infections include malaria, American trypanosomiasis, human African trypanosomiasis, toxoplasmosis, amebiasis, microsporidiasis, and leishmaniasis. The metazoal infections are grouped into flatworms, which include trematoda and cestoda, and roundworms or nematoda. Trematoda infections include schistosomiasis and paragonimiasis. Cestoda infections include cysticercosis, coenurosis, hydatidosis, and sparganosis. Nematoda infections include gnathostomiasis, angiostrongyliasis, toxocariasis, strongyloidiasis, filariasis, baylisascariasis, dracunculiasis, micronemiasis, and lagochilascariasis. The most common route of CNS invasion is through the blood. In some cases, the parasite invades the olfactory neuroepithelium in the nasal mucosa and penetrates the brain via the subarachnoid space or reaches the CNS through neural foramina of the skull base around the cranial nerves or vessels. The neuropathological changes vary greatly, depending on the type and size of the parasite, geographical strain variations in parasitic virulence, immune evasion by the parasite, and differences in host immune response. Congestion of the leptomeninges, cerebral edema, hemorrhage, thrombosis, vasculitis, necrosis, calcification, abscesses, meningeal and perivascular polymorphonuclear and mononuclear inflammatory infiltrate, microglial nodules, gliosis, granulomas, and fibrosis can be found affecting isolated or multiple regions of the CNS, or even diffusely spread. Some infections may be present as an expanding mass lesion. The parasites can be identified by conventional histology, immunohistochemistry, in situ hybridization, and PCR.

Pathology of tropical diseases

Tropical diseases affecting the central nervous system include infections, infestations, and nutritional deficiency disorders. This article discusses the commonly encountered diseases. The infections include bacterial, mycobacterial, fungal, parasitic, and viral infections with varied clinical manifestations. Imaging sensitivity and specificity for the prediction of the cause of infections has improved with application of advanced techniques. Microbial demonstration and histology remain the gold standard for diagnosis. Understanding the basis of imaging changes is mandatory for better evaluation of images. Nutritional disorders present with generalized and nonspecific imaging manifestations. The pathology of commonly encountered vitamin deficiencies is also discussed.

Helminthic invasion of the central nervous system: many roads lead to Rome

Invasion of the central nervous system (CNS) by parasitic worms often represents most severe complication of human helminthiasis. The pathways from the portal of entry to the CNS are manifold and differ from species to species. In this mini-review, we analysed the contemporary knowledge and current concepts of the routes pathogenic helminths take to gain access to brain, spinal cord and subarachnoid space.

Cardiac involvement with parasitic infections

Parasitic infections previously seen only in developing tropical settings can be currently diagnosed worldwide due to travel and population migration. Some parasites may directly or indirectly affect various anatomical structures of the heart, with infections manifested as myocarditis, pericarditis, pancarditis, or pulmonary hypertension. Thus, it has become quite relevant for clinicians in developed settings to consider parasitic infections in the differential diagnosis of myocardial and pericardial disease anywhere around the globe. Chagas' disease is by far the most important parasitic infection of the heart and one that it is currently considered a global parasitic infection due to the growing migration of populations from areas where these infections are highly endemic to settings where they are not endemic. Current advances in the treatment of African trypanosomiasis offer hope to prevent not only the neurological complications but also the frequently identified cardiac manifestations of this life-threatening parasitic infection. The lack of effective vaccines, optimal chemoprophylaxis, or evidence-based pharmacological therapies to control many of the parasitic diseases of the heart, in particular Chagas' disease, makes this disease one of the most important public health challenges of our time.

Delayed diagnosis of traumatic rupture of hydatid cyst of the liver--a case report

We present a patient with slow rupture of hydatid cyst into the peritoneal cavity, presenting as massive abdominal distension and respiratory embarrassment. On paracentesis, no fluid could be drained. A small lateral incision was made under local anaesthesia to drain the 'ascites', but daughter cysts typical of hydatid came out. On laparotomy, there was a cyst in the right lobe of liver which had ruptured into the peritoneal cavity leading to secondary echinococcosis.

Cardiac tamponade via a fistula to the pericardium from a hydatid cyst: case report and review of the literature

Although echinococcus is endemic in many sheep-raising areas of the world, cardiac involvement is rare. Cysts usually reach the heart by means of the coronary circulation, but other routes have been proposed. Pericardial tamponade due to a hydatid cyst has not yet been described in the literature. We present the case of a 46-year-old woman who presented to the Emergency Department with complaints of chest pain and mild dyspnea. Her medical history was positive for a liver hydatid cyst operation 26 years earlier. She was tachypneic, tachycardic, and hypotensive. Pleural and pericardial effusions were detected on transthoracic echocardiography. When she worsened clinically, pericardiocentesis was performed and she promptly improved. A fistula was detected between the liver and pericardium on computed tomography (CT) scan of the torso. Serologic test (agglutination) for Echinococcus granulosus was positive in a 1/32 dilution. A final diagnosis of mediastinal hydatic cyst was made, and a 4-week course of albendazol was given. Then the cyst was surgically excised, and the patient recovered without complications.

Anaphylactic shock as the only clinical manifestation of hepatic hydatid disease

The case of a 35-year-old man is reported who developed a spontaneous anaphylactic shock as the only clinical manifestation of hepatic hydatidosis. Dermatologists should consider asymptomatic hydatid disease in the differential diagnosis of anaphylactic reactions, particularly in patients from regions in which echinococcosis is endemic.

Accidental drainage of a cerebral hydatid cyst into the peritoneal cavity

Intracranial hydatidosis is more common in children than in adults. The most severe complication is anaphylactic response after direct rupture into the subarachnoid spaces. We report a case of brain hydatid cyst that was accidentally drained into the peritoneal cavity and was not complicated by an anaphylactic response or dissemination.

Antigenic glycans in parasitic infections: implications for vaccines and diagnostics

Infections by parasitic protozoans and helminths are a major world-wide health concern, but no vaccines exist to the major human parasitic diseases, such as malaria, African trypanosomiasis, amebiasis, leishmaniasis, schistosomiasis, and lymphatic filariasis. Recent studies on a number of parasites indicate that immune responses to parasites in infected animals and humans are directed to glycan determinants within cell surface and secreted glycoconjugates and that glycoconjugates are important in host-parasite interactions. Because of the tremendous success achieved recently in generating carbohydrate-protein conjugate vaccines toward microbial infections, such as Haemophilus influenzae type b, there is renewed interest in defining parasite-derived glycans in the prospect of developing conjugate vaccines and new diagnostics for parasitic infections. Parasite-derived glycans are compelling vaccine targets because they have structural features that distinguish them from mammalian glycans. There have been exciting new developments in techniques for glycan analysis and the methods for synthesizing oligosaccharides by chemical or combined chemo-enzymatic approaches that now make it feasible to generate parasite glycans to test as vaccine candidates. Here, we highlight recent progress made in elucidating the immunogenicity of glycans from some of the major human and animal parasites, the potential for developing conjugate vaccines for parasitic infections, and the possible utilization of these novel glycans in diagnostics.

Giant Supratentorial Enterogenous Cyst: Report of a Case, Literature Review, and Discussion of Pathogenesis

OBJECTIVE AND IMPORTANCE

To describe a histologically well-documented adult case of a giant supratentorial enterogenous cyst (EC). Fewer than 15 cases of supratentorial ECs are on record: 8 associated with the brain hemispheres or the overlying meninges, 4 with the sellar region, and 2 with the optic nerve.

CLINICAL PRESENTATION

A 31-year-old woman complained of long-standing mild left brachial and crural motor deficit precipitated by headache and signs of intracranial hypertension. Magnetic resonance imaging revealed a huge cyst overlying the frontoparietal brain.

INTERVENTION

Symptoms were relieved by evacuation of the cyst content by means of a Rickam's reservoir, and the lesion was subsequently removed in toto. Histological and immunohistochemical examination of the cyst wall clearly established the enterogenous nature of its epithelium. Follow-up for up to 2 years after intervention showed no sign of recurrence, and symptoms, including treatment-resistant seizures in the postoperative period, have entirely subsided.

CONCLUSION

Supratentorial ECs, distinctly rare in adult patients, may in some cases present as giant lesions. Total removal seems to be curative once careful examination has eliminated the possibility of a metastasis from an unknown primary. A correct histological diagnosis is important because, in contrast to other benign cysts of similar location and size, ECs may be prone to intraoperative dissemination.

Stage-specific expression and targeting of cyst wall protein-green fluorescent protein chimeras in Giardia

In preparation for being shed into the environment as infectious cysts, trophozoites of Giardia spp. synthesize and deposit large amounts of extracellular matrix into a resistant extracellular cyst wall. Functional aspects of this developmentally regulated process were investigated by expressing a series of chimeric cyst wall protein 1 (CWP1)-green fluorescent protein (GFP) reporter proteins. It was demonstrated that a short 110 bp 5' flanking region of the CWP1 gene harbors all necessary cis-DNA elements for strictly encystation-specific expression of a reporter during in vitro encystation, whereas sequences in the 3' flanking region are involved in modulation of steady-state levels of its mRNA during encystation. Encysting Giardia expressing CWP1-GFP chimeras showed formation and maturation of labeled dense granule-like vesicles and subsequent incorporation of GFP-tagged protein into the cyst wall, dependent on which domains of CWP1 were included. The N-terminal domain of CWP1 was required for targeting GFP to regulated compartments of the secretory apparatus, whereas a central domain containing leucine-rich repeats mediated association of the chimera with the extracellular cyst wall. We show that analysis of protein transport using GFP-tagged molecules is feasible in an anaerobic organism and provides a useful tool for investigating the organization of primitive eukaryotic vesicular transport.