Parasitic diseases of the central nervous system

Multiantigen print immunoassay (MAPIA) for the diagnosis of neurocysticercosis: a single-center diagnostic optimization and accuracy study in Lima, Peru

Neurocysticercosis (NCC) is the most common helminthic infection of the human central nervous system. The antibody detection assay of choice is the enzyme-linked immunoelectrotransfer blot assay using lentil-lectin purified parasite antigens (LLGP-EITB, Western blot), an immunoassay with exceptional performance in clinical samples. However, its use is mainly restricted to a few research laboratories because the assay is labor-intensive and requires sophisticated equipment, expertise, and large amounts of parasite material for preparation of reagents. We report a new immunoprint assay (MAPIA) that overcomes most of these barriers. We initially compared the performance of five different antigen combinations in a subset of defined samples in the MAPIA format. After selecting the best-performing assay format (a combination of rGP50 + rT24H + sTs14 antigens), 148 archived serum samples were tested, including 40 from individuals with parenchymal NCC, 40 with subarachnoid NCC, and 68 healthy controls with no evidence of neurologic disease. MAPIA using three antigens (rGP50 + rT24H + sTs14) was highly sensitive and specific for detecting antibodies in NCC. It detected 39 out of 40 (97.5%) parenchymal NCC cases and 40/40 (100%) subarachnoid cases and was negative in 67 out of 68 (98.53%) negative samples. MAPIA using three recombinant and synthetic antigens is a simple and economical tool with a performance equivalent to the LLGP-EITB assay for the detection of specific antibodies to NCC. The MAPIA overcomes existing barriers to adoption of the EITG LLGP and is a candidate for worldwide use.

Racemose neurocysticercosis presenting with thalamic stroke: A case report and literature review

Racemose neurocysticercosis is an uncommon type of neurocysticercosis that represents a particularly aggressive infection. It is characterized by the presence of multiple confluent cysts within the subarachnoid space and it carries unique diagnostic challenges. Clinical manifestations include headache, cerebrovascular events, and life-threatening hydrocephalus. A 56-year-old female presented with sudden onset headache and right-sided hemisensory loss. Brain MRI revealed multiple cystic lesions in the subarachnoid space consistent with racemose neurocysticercosis and left thalamus acute lacunar infarct. This case report emphasizes the clinical importance, unique characteristics, and imaging features of racemose neurocysticercosis and its complications.

Consistent Measurement of Parasite-Specific Antigen Levels in Sera of Patients with Neurocysticercosis Using Two Different Monoclonal Antibody (mAb)-Based Enzyme-Linked Immunosorbent Assays

Monoclonal antibody (mAb)-based enzyme-linked immunosorbent assay (ELISA) is a complementary diagnosis technique for neurocysticercosis (NCC), which detects circulating parasite antigen (Ag) indicative of viable infection and Ag levels that correlate well with the parasite burden. In this study, we compared the performance of two Ag-ELISA techniques for the detection of NCC. We assessed the agreement between our in-house TsW8/TsW5 Ag-ELISA and the widely used B158/B60 Ag-ELISA for measuring T. solium antigen levels in the sera from 113 patients with calcified, parenchymal, and subarachnoid NCC. Concordance was demonstrated evaluating the limits of agreement (LoAs) stratified by the type of NCC. Both ELISA's detected 47/48 (97.8%) subarachnoid NCC cases. In parenchymal and calcified NCC, the B158/B60 Ag-ELISA detected 19/24 (79.2%) and 18/41 (43.9%) cases, while the TsW8/TsW5 Ag-ELISA detected 21/24 (87.5%) and 13/41 (31.7%), respectively. Parenchymal and calcified NCC obtained a perfect agreement (100%), indicating that all sample results were within the predicted LoA, while for subarachnoid NCC, the agreement was 89.6%. The high concordance between the assays was confirmed by Lin's concordance coefficient (LCC = 0.97). Patients with viable parenchymal NCC (LCC = 0.95) obtained the highest concordance between assays, followed by subarachnoid NCC (LCC = 0.93) and calcified NCC (LCC = 0.92). The TsW8/TsW5 Ag-ELISA and B158/B60 Ag-ELISA showed high Ag measurement correlations across diverse types of NCC.

Acrophialophora: A Comprehensive Review of Clinical Guidelines and Diagnosis

Acrophialophora is a saprotrophic genus of fungi found in both temperate and tropical regions. The genus is comprised of 16 species, with the subspecies A. fusispora and A. levis necessitating the most clinical concern. Acrophialophora is an opportunistic pathogen with a broad range of clinical manifestations; the fungus has been implicated in cases of fungal keratitis, lung infection, and brain abscess. Acrophialophora infection is particularly of concern for immunocompromised patients, who often present with a more severe disease course involving disseminated infection and may not exhibit typical symptoms. Early diagnosis and therapeutic intervention are critical to the successful clinical management of Acrophialophora infection. Guidelines for antifungal treatment have yet to be established, partially due to the lack of documented cases. Aggressive use of antifungal agents and long-term treatment is required, especially in immunocompromised patients and patients with systemic involvement, due to the potential for morbidity and mortality. In addition to outlining the rarity and epidemiology of the disease, this review provides an overview of the diagnosis and clinical management of Acrophialophora infection to facilitate an early diagnosis and appropriate interventions.

Cerebral paragonimiasis: Clinicoradiological features and serodiagnosis using recombinant yolk ferritin

Cerebral paragonimiasis (CP), caused by aberrant migration of Paragonimus worms, frequently invokes serious illness. The causal relationship between the lesion characteristics and patients’ symptoms has poorly been understood. CP serodiagnosis has not been properly evaluated to date. A total of 111 CP cases were diagnosed in our laboratory between 1982 and 2003. This study retrospectively assessed the clinical and imaging characteristics of the 105 patients along with the evaluation of diagnostic potentials of recombinant P. westermani yolk ferritin (rPwYF) by enzyme-linked immunosorbent assay (ELISA) employing patients’ sera and cerebrospinal fluids (CSFs). We analyzed 60 male and 45 female patients; 50 early-stage patients with non-calcified enhancing nodule(s) (median age, 38 years; interquartile range [IQR], 24.75–52; median symptom duration, 0.75 years; IQR, 0.2–2) and 54 chronic cases having calcified lesion(s) (median age, 33 years; IQR, 25–41; median symptom duration, 10 years; IQR, 5–20). One patient showed a normal neuroimage. The patients were largely diagnosed in their 30s. The parietal lobe was most commonly affected, followed by occipital, frontal, and temporal lobes. Twenty-six patients had lesions encompassing ≥ two lobes. The patients complained mainly of seizures, headaches, hemiparesis, and focal neurologic deficits (P < 0.001). Seizures and visual defects were predominant in patients with calcified lesion(s) (P < 0.001). The diagnostic sensitivity and specificity of rPwYF against serum/CSF were 100%/97% and 97.2%/92.5%, respectively. The specific IgG antibody levels against rPwYF in sera and CSFs showed a positive correlation (r = 0.59). The clinical manifestations of the early-stage patients might be associated with cortical lesions or meningeal irritation, while those in the chronic stage were caused by conglomerated space-occupying lesions. rPwYF would be useful for the serodiagnosis of both early and chronic CP cases.

Paragonimiasis, caused by the lung fluke Paragonimus spp., is a global foodborne zoonosis of great public health concern. Paragonimiasis is primarily a pleuropulmonary disease. However, the worms sometimes migrate aberrantly to other parts of the body, thereby causing the granulomatous lesion(s). The most serious condition elicited by ectopic migration is cerebral paragonimiasis. This study retrospectively analyzed the clinical and imaging features of the largest number of 105 cases diagnosed between 1982 and 2003 in our laboratory. We also evaluated diagnostic feasibility of recombinant P. westermani yolk ferritin by ELISA. The patients were largely diagnosed in their 30s with the chief complaints of seizures, headaches, hemiparesis, and focal neurologic deficits. Seizures and visual defect were significant in the chronic stage patients having calcified lesion(s). The diagnostic sensitivity and specificity of recombinant P. westermani yolk ferritin by ELISA against patients’ sera or CSFs were 100% or 97%, and 97.2% or 92.5%, respectively. The diverse neurological manifestations of patients might be related to the nature and/or location of the lesions. P. westermani yolk ferritin is a promising antigen for serodiagnosis of both early-stage patients with non-calcified lesion(s) and chronic calcified cerebral paragonimiasis cases.

Case Report: Moving Tumor-Like Foci Behind Refractory Epilepsy-Cerebral Sparganosis Successfully Treated by Surgery After Failure of Praziquantel Treatment

Cerebral sparganosis is clinically non-specific and easily misdiagnosed, exposing patients to the risk of severe brain damage and neurological dysfunction caused by actively migrating larvae. Diagnostic biomarkers from typical cases can help to establish an early diagnosis and proper treatment. We present a 25-year-old woman who suffered from 9 years of refractory epilepsy and was misdiagnosed with glioma and subjected to surgery. The postoperative pathology confirmed granuloma, and the tumor-like foci reappeared 3 months later. Along with the “tunnel sign” on MRI, cerebral sparganosis was suspected and confirmed by positive serum and cerebrospinal fluid antibodies against Spirometra mansoni. The patient visited us after a failure of four cycles of praziquantel treatment, recurrent seizures and hemiplegia with basal ganglia foci. Craniotomy was not carried out until the larva moved to the superficial lobe on follow-up MRIs, and pathology revealed sparganosis granuloma. The patient became seizure-free and recovered myodynamia but had long-lasting cognitive dysfunction due to severe brain damage. This case indicated the importance of tunnel signs and moving tumor-like foci on MRI as diagnostic clues of cerebral sparganosis. An early diagnosis is vitally important to avoid severe neural dysfunction by the long-living and moving larvae. Surgical removal of the larva is a critical remedy for cases failed by praziquantel treatment.

Advanced magnetic resonance imaging and spectroscopy in a case of neurocysticercosis from North America

Neurocysticercosis (NCC) is a parasitic infection caused by Cysticercus cellulosae, the metacestode of pork tapeworm (Taenia solium). NCC is one of the most common public health problems worldwide. We present a patient harboring a bilobed ring-enhancing lesion with a presumed diagnosis of brain metastasis, who returned to the USA after traveling to an endemic region. The diagnosis of NCC was established based on a characteristic resonance of succinate on proton magnetic resonance spectroscopy. Also, higher mean diffusivity and lower fractional anisotropy along with relative cerebral blood volume were observed from the lesion compared to contralateral normal brain regions. Multiparametric analysis may improve the differential diagnosis of ring-enhancing intracranial lesions such as NCC.

Migration characteristics as a prognostic factor in cerebral sparganosis

OBJECTIVE

To differentiate diagnostic and prognostic factors from the clinical material of patients with cerebral sparganosis in central South China.

METHODS

Consecutive patients with cerebral sparganosis from our hospital between 2010 and 2018 were retrospectively enrolled. The clinical manifestations, radiographic features, treatment, and outcomes of these patients were analyzed.

RESULTS

Thirty patients with cerebral sparganosis were included, and foci migration on magnetic resonance imaging was detected in 22 patients, from whom we observed 4 migration modes: interlobar migration (50.0%, 11/22); transmidline migration (27.3%, 6/22); transventricular migration (13.6%, 3/22); and cerebellum-brainstem migration (9.1%, 2/22). The percentage of good outcomes was higher in patients with live worm capture than in those without live worm capture (75.0%, 12/16 vs 33.3%, 2/6). Exposure to preoperative antiparasitic medication was associated with worm migration toward the cortical surface, which led to a higher probability of live worm capture.

CONCLUSIONS

We propose 4 modes of sparganosis migration that are correlated with worm capture and neurologic prognosis. We found that exposure to antiparasitic medication was associated with worm migration toward the cortical surface, leading to a higher probability of live worm capture. These observations suggest a novel significance for preoperative medication of cerebral sparganosis.

Intrahepatic manifestation and distant extrahepatic disease in alveolar echinococcosis: a multicenter cohort study

BACKGROUND

The main endemic areas of alveolar echinococcosis (AE) are in central Europe and western China. The infiltration of intrahepatic vascular and bile ducts as well as extrahepatic disease can lead to complications and may increase morbidity in AE.

PURPOSE

To evaluate the vascular/biliary involvement of hepatic alveolar echinococcosis (HAE) and distant extrahepatic disease at each of four locations in Germany, France, and China.

MATERIAL AND METHODS

Contrast-enhanced abdominal magnetic resonance imaging (MRI) scans of patients with HAE, 200 in total, were evaluated by five examiners. AE liver lesions were classified according to Kodama's classification. Furthermore, distant extrahepatic manifestations were documented with additionally performed imaging modalities. Vascular/biliary involvement of hepatic manifestations as well as the presence of extrahepatic manifestations were correlated with the respective Kodama type of the liver lesion.

RESULTS

Distant extrahepatic AE manifestations were significantly more frequent in China than in Europe (12/100 vs. 3/100; Fisher's exact test: P=0.0286). A significant relationship exists between presence of distant extrahepatic disease manifestation and size of the AE liver lesion (132.53 ± 48.65 vs. 92.49 ± 50.06; P = 0.0030). Vascular/biliary involvement is significantly more frequent in China than in Europe (86/100 vs. 65/100; χ² = 11.92; P = 0.0006). Vascular/biliary involvement depends on lesion size (111.10 ± 47.44 vs. 47.36 ± 24.36; P<0.0001). Different types of AE liver lesions are associated with differences in vascular/biliary involvement and extrahepatic manifestations.

CONCLUSION

Vascular/biliary involvement and presence of distant extrahepatic manifestations depend on size of the HAE lesions and are more frequently detected in China. Different MRI morphological patterns influence vascular/biliary involvement and the occurrence of distant extrahepatic manifestations.

Diffusion-weighted MRI and FLAIR sequence for differentiation of hydatid cysts and simple cysts in the liver

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DWI signal characteristics are useful in differentiating between hydatid cysts and simple cysts.

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ADC values (b600 and b1000) can distinguish hydatid cyst and simple cyst.

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FLAIR sequence contributes to the differentiation of type 2 hydatid and simple cysts.

Purpose

The contribution of DWI and FLAIR to the differential diagnosis of type 1, 2, and 3 hydatid cysts and simple liver cysts was investigated according to the Gharbi classification. This study is the first report using FLAIR sequence for the differential diagnosis of liver hydatid cysts in this regard.

Methods

A total of 82 hydatid cysts and 40 simple cysts were scanned with DWI (in b600-b1000 values) and FLAIR sequence. In 64 patients included in the study, a total of 122 cystic lesions were diagnosed histopathologically or during follow-up. FLAIR and DWI signal characteristics were evaluated, and ADC values were calculated.

Results

The mean ADC value of hydatid cysts on DWI (b600) was 3.07 ± 0.41 × 10⁻³ s/mm², while it was 3.91 ± 0.51 × 10⁻³ s/mm² for simple cysts and the difference was statistically significant (p < 0.05). On b1000 DWI, the mean ADC values of hydatid and simple cysts were 2.99 ± 0.38 × 10⁻³ s/mm² and 3.43 ± 0:29 × 10⁻³ s/mm², respectively (p < 0.05). The qualitative evaluation of the signal intensity on b600−1000 DWI demonstrated the difference between the simple and hydatid cyst groups (p < 0.05). Type 2 hydatid cysts alone were distinguished from type 2–3 hydatid and simple cysts by FLAIR (p < 0.05).

Conclusions

ADC values can distinguish between hydatid cyst and simple cyst. FLAIR contributes to the differentiation of type 2 hydatid and simple cysts.

Intracranial Abnormalities with Diffusion Restriction

Multiple pathologic conditions can cause changes in the random movement of water, which can be detected with diffusion-weighted imaging (DWI). DWI plays a powerful clinical role in detecting restricted diffusion associated with acute brain infarction. Other disorders can also result in restricted diffusion. This article focuses on showing examples of common and uncommon disorders that have restricted diffusion secondary to cytotoxic and/or intramyelinic edema. These disorders include ischemia, infection, noninfectious demyelinating diseases, genetic mutations affecting metabolism, acquired metabolic disorders, toxic or drug exposures, neoplasms and tumorlike lesions, radiation treatment, trauma, and denervation.

Differential diagnosis of brain lesions in a metastatic endometrial carcinosarcoma patient

The differential diagnosis of ring-enhancing brain lesions in a patient with metastatic malignancy may initially seem straightforward, and easily attributed to brain metastases. On rare occasions, the physician needs to avoid anchoring bias by re-evaluating the entire clinical context in which these ring-enhancing brain lesions are found. We report a case of cerebral toxoplasmosis mimicking brain metastases in a patient with metastatic cancer and without a prior history of human immunodeficiency virus. A 65-year-old lady with a recently detected relapse of her endometrial carcinosarcoma presented with a 2-week history of fever with no localising symptoms or signs of infection. The initial investigations were unremarkable. She had daily fever despite empirical broad-spectrum antibiotics. A positron emission tomography-computed tomography (PET-CT) was performed to evaluate the pyrexia of unknown origin, which showed metastatic deposits in the pelvis. A magnetic resonance imaging (MRI) of the brain was subsequently performed due to fluctuating mentation, which reported metastatic disease to the brain. Her pyrexia of unknown origin was attributed to malignancy-related fever. The medical oncologist was cautious about starting systemic treatment because the PET-CT had FDG-avid diffuse ground glass opacities in both lung fields, and requested for a bronchoscopic evaluation, which returned positive for Pneumocystis jirovecii. In light of this new finding, a multi-disciplinary discussion and a review of the brain MRI were undertaken, during which it was concluded that the likelihood of cerebral toxoplasmosis was much higher than brain metastases. She was treated with high dose trimethoprim-sulfamethoxazole for both P. jirovecii pneumonia and cerebral toxoplasmosis, with clinical and radiological improvement. This case highlights the importance of (a) clinical input in interpreting imaging findings, (b) entertaining the possibility of multiple concurrent pathologies explaining a patient’s symptoms, (c) being open to alternate diagnoses when new information surfaces even though the current working diagnosis is the most plausible and (d) multi-disciplinary communication when faced with diagnostic difficulty.

The clinical features of chronic intestinal schistosomiasis-related intestinal lesions

Background

Chronic intestinal schistosomiasis has been reported to be associated with colonic polyps, colorectal cancer and ulcerative colitis. We aim to investigate the clinical characteristics of intestinal-related lesions caused by chronic intestinal schistosomiasis japonicum.

Methods

Patients with and without chronic intestinal schistosomiasis were retrospectively enrolled from the endoscopy center of Wuhan Union Hospital from September 1, 2014, to June 30, 2019 with a ratio of 4:1. The characteristics of infected intestinal segments were analyzed in patients with chronic intestinal schistosomiasis. We also compared the characteristics of intestinal-related lesions, including colorectal polyps, colorectal cancer (CRC), ulceration or erosion of the intestinal mucosa and hemorrhoids, between the two groups.

Results

A total of 248 patients with chronic intestinal schistosomiasis and 992 patients without chronic intestinal schistosomiasis were analyzed. The most common sites of chronic intestinal schistosomiasis were the sigmoid colon (79.0%) and rectum (84.7%). The frequency of intestinal polyps (64.5% vs. 42.8%, p < 0.001), especially rectal polyps (62.5% vs. 45.0%, p = 0.002), in the intestinal schistosomiasis group was significantly higher than that in the control group. Morphologically, type IIa polyps were more common in the schistosomiasis enteropathy group (68.5% vs. 60.7%, p = 0.001). Female patients with intestinal schistosomiasis had a higher detection rate of CRC than women in the control group (13.8% vs. 5.4%, p = 0.017). There was no significant difference in the incidence of ulcerative colitis between the two groups (0.8% vs. 0.6%, p = 0.664). In addition, the schistosomiasis enteropathy patients had a higher detection rate of internal hemorrhoids (58.9% vs. 51.0%, p = 0.027).

Conclusions

Chronic intestinal schistosomiasis mainly involved the rectum and sigmoid colon and was more likely to induce intestinal polyps, especially rectal polyps and internal hemorrhoids. Women with chronic schistosomiasis have a higher risk of colorectal cancer.

Quantitative assessment of lesion load and efficacy of 3 cycles of albendazole in disseminated cysticercosis: a prospective evaluation

BACKGROUND

The management of disseminated cysticercosis is unclear and largely considered hazardous. The role of albendazole remains controversial in such patients.

METHODS

A tertiary care, University hospital-based prospective intervention study was conducted from December 2015 to December 2017. Patients with disseminated cysticercosis, defined as the presence of multiple viable neurocysticerci (≥ 3) in the brain along with involvement of an additional extra site, were included in the study. Patients with cysticercal encephalitis were excluded. A detailed evaluation, including ophthalmoscopy, ocular B scans, ultrasound abdomen, and X-rays were done. Albendazole was administered at a dose of 15 mg/kg/day in 3 cycles of 28 days each. All patients were also given adjuvant corticosteroids and anti-epileptic drugs. Clinical and radiological follow up was carried out at a difference of 3 months between each treatment cycle. For radiological quantification, lesions were counted at 10 pre-specified levels. Statistical analysis was done to estimate the difference in seizure frequency and lesion load.

RESULTS

Twenty-nine patients (21 with > 20 lesions; 8 with ≤ 20 lesions) were given albendazole as per the protocol. There was a significant reduction in the occurrence of seizures (P < 0.001) and headache (P < 0.001). A significant reduction in lesion load from baseline to third follow-up was seen in the estimations done at different levels (P < 0.001). No patient developed serious side-effect warranting cessation of therapy.

CONCLUSION

Cyclical use of albendazole appears efficacious in treating disseminated cysticercosis. The method of quantification described may be used in future studies for objective assessment.

TRIAL REGISTRATION

ISRCTN11630542; 28th September 2019; Retrospectively registered.

Simultaneous Paragonimus infection involving the breast and lung: A case report

BACKGROUND

Paragonimiasis is a food-borne parasitic infection caused by lung flukes of the genus Paragonimus. Although the most common site of infection is the pleuropulmonary area, the parasite can also reach other parts of the body on its journey from the intestines to the lungs, ending up in locations such as the brain, abdomen, skin, and subcutaneous tissues. Ectopic paragonimiasis is difficult to diagnose due to the rarity of this disease.

CASE SUMMARY

Here, we report a rare case of simultaneous breast and pulmonary paragonimiasis in a woman presenting painless breast mass and lung nodule with a history of eating raw trout. To confirm the diagnosis, serologic testing and tissue confirmation of the breast mass were performed. The patient was treated with surgical resection of the mass and praziquantel medication.

CONCLUSION

Ectopic paragonimiasis is difficult to diagnose due to the rarity of this disease. Thus, thorough history-taking and clinical suspicion of parasitic infection are important.

Cryptococcal Meningitis Presenting as New-Onset Seizures in an Immunocompetent Patient

This report describes a 30-year-old immunocompetent male with new-onset seizures, later found on imaging to have 2 enhancing lesions in the brain. The patient underwent a left parietal craniectomy with resection of one of the masses, which demonstrated focal areas of necrosis and many small cystic structures positive for periodic acid-Schiff and Gomori's methenamine silver special stain. Numerous laboratory examinations, including HIV test, rapid plasma reagin, toxoplasma immunoglobulin G and immunoglobulin M, Lyme, cytomegalovirus, tuberculosis, cysticercosis, and Echinococcus serology, were all negative. Despite negative cerebrospinal fluid (CSF) culture and several negative CSF antigen tests, continued investigation, and follow-up, CSF antigen testing ultimately revealed Cryptococcus as the causative agent. In light of the mysterious and unusual presentation, the authors discuss potential infectious differential diagnoses in patients with atypical clinical presentation, laboratory tests, and surgical pathology.

Clinical applications of diffusion weighted imaging in neuroradiology

Abstract

Diffusion-weighted imaging (DWI) has revolutionised stroke imaging since its introduction in the mid-1980s, and it has also become a pillar of current neuroimaging. Diffusion abnormalities represent alterations in the random movement of water molecules in tissues, revealing their microarchitecture, and occur in many neurological conditions. DWI provides useful information, increasing the sensitivity of MRI as a diagnostic tool, narrowing the differential diagnosis, providing prognostic information, aiding in treatment planning and evaluating response to treatment. Recently, there have been several technical improvements in DWI, leading to reduced acquisition time and artefacts and enabling the development of diffusion tensor imaging (DTI) as a tool for assessing white matter. We aim to review the main clinical uses of DWI, focusing on the physiological mechanisms that lead to diffusion abnormalities. Common pitfalls will also be addressed.

Teaching Points

• DWI includes EPI, TSE, RESOLVE or EPI combined with reduced volume excitation.

• DWI is the most sensitive sequence in stroke diagnosis and provides information about prognosis.

• DWI helps in the detection of intramural haematomas (arterial dissection).

• In diffusion imaging, ADC is inversely proportional to tumour cellularity.

• DWI and DTI derived parameters can be used as biomarkers in different pathologies.

Intracranial Infectious and Inflammatory Diseases Presenting as Neurosurgical Pathologies

There are many infectious and inflammatory processes affecting the central nervous system that can simulate other neurosurgical pathologies (e.g. tumor) and may precipitate a brain biopsy for definitive diagnosis if not suspected a priori. The challenge for the healthcare team is to recognize imaging features that support a nonsurgical pathology to avoid unnecessary interventions. This review aims to give a general overview of some common inflammatory and infectious entities that affect the central nervous system, with illustrative examples and highlighting important pearls and pitfalls.

Hydatid disease: MR imaging of calvarium and superior sagittal sinus involvement

Extra-axial hydatid disease (HD) is rare and may create a diagnostic challenge. Herein, we report an extremely rare case of calvarial HD with superior sagittal sinus invasion and an extension to the scalp with unusual magnetic resonance imaging findings simulating osteomyelitis and abscess. Recognition of detached endocystic membranes was the most important clue for the correct diagnosis. HD should be included in the differential diagnosis for a patient having a destructive skull lesion with peripheral enhancing extra-axial soft tissue component. Preoperative correct imaging diagnosis is crucial to improving patient management.

Cerebral Toxoplasmosis: A Case Report with Correlation of Radiographic Imaging, Surgical Pathology, and Autopsy Findings

Cerebral toxoplasmosis is an opportunistic infection of the central nervous system. Certain radiographic findings can be highly suggestive of the disease, but there is considerable overlap with both lymphoma and brain metastases, making the diagnosis difficult or delayed. Herein we present the case of a 77-year-old woman with a history of treated diffuse large B-cell lymphoma who presented with neurological symptoms four months after she was declared to be in remission. Her initial head computed tomography scan showed multiple low-attenuated lesions in her brain and a contrast enhanced magnetic resonance imaging scan showed multiple T1- and T2- enhancing lesions in the basal ganglia and at the gray-white junction. The clinical team was highly suspicious of a recurrence of her lymphoma so she had an extensive workup, including a brain biopsy, which did not lead to a definite diagnosis. After she died, an autopsy was performed, and multiple necrotic lesions were discovered in her brain. Histologic sections demonstrated numerous parasitic organisms, and immunohistochemical staining for Toxoplasma gondii was positive, confirming the diagnosis of cerebral toxoplasmosis. This case highlights an unusual case of cerebral toxoplasmosis that was diagnosed at autopsy and reviews the relevant radiographic findings as well as the gross and microscopic pathological features of the disease.

Parasitic diseases of the central nervous system: lessons for clinicians and policy makers

Parasitic diseases of the central nervous system are associated with high mortality and morbidity, especially in resource-limited settings. The burden of these diseases is amplified as survivors are often left with neurologic sequelae affecting mobility, sensory organs, and cognitive functions, as well as seizures/epilepsy. These diseases inflict suffering by causing lifelong disabilities, reducing economic productivity, and causing social stigma. The complexity of parasitic life cycles and geographic specificities, as well as overlapping clinical manifestations in the host reflecting the diverse pathogenesis of parasites, can present diagnostic challenges. We herein provide an overview of these parasitic diseases and summarize clinical aspects, diagnosis, therapeutic strategies and recent milestones, and aspects related to prevention and control.

Cerebral toxoplasmosis in a diffuse large B cell lymphoma patient

Background

Toxoplasmosis is an opportunistic protozoal infection that has, until now, probably been an underestimated cause of encephalitis in patients with hematological malignancies, independent of stem cell or bone marrow transplant. T and B cell depleting regimens are probably an important risk factor for reactivation of a latent toxoplasma infection in these patients.

Case report

We describe a 62-year-old HIV-negative right-handed Caucasian female with systemic diffuse large B cell lymphoma who presented with sudden onset of high fever, headache, altered mental status, ataxia and findings of pancytopenia, a few days after receiving her final, 8^th cycle of rituximab, cyclophosphamide, vincristine, doxorubicin, prednisolone (R-CHOP) chemotherapy regimen. A progression of lymphoma to the central nervous system was suspected. MRI of the head revealed multiple on T2 and fluid attenuated inversion recovery (FLAIR) hyperintense parenchymal lesions with mild surrounding edema, located in both cerebral and cerebellar hemispheres that demonstrated moderate gadolinium enhancement. The polymerase chain reaction on cerebrospinal fluid (CSF PCR) was positive for Toxoplasma gondii. The patient was diagnosed with toxoplasmic encephalitis and successfully treated with sulfadiazine, pyrimethamine and folic acid. Due to the need for maintenance therapy with rituximab for lymphoma remission, the patient now continues with secondary prophylaxis of toxoplasmosis.

Conclusions

With this case report, we wish to emphasize the need to consider cerebral toxoplasmosis in patients with hematological malignancies on immunosuppressive therapy when presenting with new neurologic deficits. In such patients, there are numerous differential diagnoses for cerebral toxoplasmosis, and the CNS lymphoma is the most difficult among all to distinguish it from. If left untreated, cerebral toxoplasmosis has a high mortality rate; therefore early recognition and treatment are of essential importance.

Parasitic and rare spinal infections

The imaging features of spinal parasitic diseases and other rare infections are herein discussed. These diseases are distributed worldwide, with increased prevalence in areas with poor sanitary conditions and in developing countries. In nonendemic areas, sporadic cases may occur, consequent to increased international travel and immunocompromising conditions. Infectious diseases are usually treatable, and early detection is often crucial. A thorough comprehension of the imaging patterns associated with the clinical features, epidemiology, and laboratory results allows the radiologist to narrow down the options for differential diagnosis and facilitates the timely implementation of appropriate therapies.

Toxocariasis: A Rare Cause of Multiple Cerebral Infarction

Toxocariasis is a parasitic infection caused by the roundworms Toxocara canis or Toxocara cati, mostly due to accidental ingestion of embryonated eggs. Clinical manifestations vary and are classified as visceral larva migrans or ocular larva migrans according to the organs affected. Central nervous system involvement is an unusual complication. Here, we report a case of multiple cerebral infarction and concurrent multi-organ involvement due to T. canis infestation of a previous healthy 39-year-old male who was admitted for right leg weakness. After treatment with albendazole, the patient's clinical and laboratory results improved markedly.

Cerebral paragonimiasis: a retrospective analysis of 27 cases

OBJECT

The authors retrospectively analyzed the clinical characteristics, existing problems, and treatment experiences in recently diagnosed cerebral paragonimiasis (CP) cases and sought to raise awareness of CP and to supply reference data for early diagnosis and treatment.

METHODS

Twenty-seven patients (22 male and 5 female; median age 20.3 years, range 4-47 years) with CP were diagnosed between September 2008 and September 2013. These diagnoses were confirmed by IgG enzyme-linked immunosorbent assays. Follow-up was performed in 24 cases for a period of 6-56 months.

RESULTS

Cerebral paragonimiasis accounted for 21.6% of paragonimiasis cases (27 of 125). The average duration from onset to praziquantel treatment was 69 days. All patients resided in rural areas. Twenty patients had positive lung results, which included visible lung lesions in 14 cases. The lesions were surgically removed in 8 of these cases. Twenty-four patients had high eosinophil counts (≥ 0.08 × 10(9)/L), and eosinophilic meningitis was noted in 17 cases. The rate of misdiagnosis and missed diagnosis was 30.4%. Most symptoms were markedly improved after treatment, but mild movement disorders combined with impaired memory and personality changes remained in a small number of patients.

CONCLUSIONS

Clinicians should be alert to the possibility of CP in young patients (4-16 years) with the primary symptoms of epilepsy and hemorrhage. Early diagnosis and timely treatment can reduce the need for surgery and further impairments to brain function. Liquid-based cytological examination of CSF and peripheral blood eosinophil counts can aid in differentiating CP from similar lesions.

Imaging in neurologic infections I: bacterial and parasitic diseases

Often presenting as medical emergencies, nervous system infections can be diagnostically challenging. Knowledgeable utilization of neuroimaging modalities and the understanding of characteristic imaging findings facilitate early diagnosis and treatment. In the first part of this two-part review, we address common and unique diagnostic imaging features of bacterial and parasitic nervous system infections.

Parasitoses with central nervous system involvement

Most of the parasitoses manifest systemically, including the central nervous system (CNS). Among the most prevalent parasitoses in Central Europe (cysticercosis, toxocarosis, echinococcosis, and toxoplasmosis), cerebral involvement is well recognized and part of the clinical presentation, which cannot be neglected. CNS involvement results from invasion of larvae of these parasites via the blood stream or by direct migration into the CNS. Most frequently larvae reside within the cerebral parenchyma, but sometimes also within the ventricles, in the meningeas within cerebral aneurysms, or in the parenchyma of the spinal cord. Depending on the stage of their development, they cause a local defect or more widespread damage, such as encephalitis, ventriculitis, ependymitis, arachnoiditis, meningitis, myelitis, polyradiculitis, mechanical obstruction of the arterial or cerebrospinal fluid (CSF) flow, or vasculitis with appropriate clinical presentations. These include epilepsy, headache, impaired consciousness, orientation, cognition, focal neurological motor, sensory, or vegetative deficits, or visual impairment. CNS involvement is diagnosed on the clinical presentation, the epidemiological background, blood and CSF investigations, imaging studies, and sometimes biopsy. Treatment is based on various antihelminthic agents and, occasionally, surgery.

Neuroimaging of infectious disease

This article provides an imaging overview of several of the common central nervous system (CNS) infections. Neurologic clinicians who provide acute care for patients should be familiar with the range of imaging findings for patients with acute neurologic infections, including knowledge of the appropriate study and the best protocol and views to show the disorder, and the ability to properly interpret them. This requirement applies particularly for CNS infections, as in stroke, in which a rapid appreciation of the exact cause of a patient's infection may play a major role in reducing mortality and morbidity.

Midichlorians--the biomeme hypothesis: is there a microbial component to religious rituals?

Background

Cutting edge research of human microbiome diversity has led to the development of the microbiome-gut-brain axis concept, based on the idea that gut microbes may have an impact on the behavior of their human hosts. Many examples of behavior-altering parasites are known to affect members of the animal kingdom. Some prominent examples include Ophiocordyceps unilateralis (fungi), Toxoplasma gondii (protista), Wolbachia (bacteria), Glyptapanteles sp. (arthropoda), Spinochordodes tellinii (nematomorpha) and Dicrocoelium dendriticum (flat worm). These organisms belong to a very diverse set of taxonomic groups suggesting that the phenomena of parasitic host control might be more common in nature than currently established and possibly overlooked in humans.

Presentation of the hypothesis

Some microorganisms would gain an evolutionary advantage by encouraging human hosts to perform certain rituals that favor microbial transmission. We hypothesize that certain aspects of religious behavior observed in the human society could be influenced by microbial host control and that the transmission of some religious rituals could be regarded as the simultaneous transmission of both ideas (memes) and parasitic organisms.

Testing the hypothesis

We predict that next-generation microbiome sequencing of samples obtained from gut or brain tissues of control subjects and subjects with a history of voluntary active participation in certain religious rituals that promote microbial transmission will lead to the discovery of microbes, whose presence has a consistent and positive association with religious behavior. Our hypothesis also predicts a decline of participation in religious rituals in societies with improved sanitation.

Implications of the hypothesis

If proven true, our hypothesis may provide insights on the origin and pervasiveness of certain religious practices and provide an alternative explanation for recently published positive associations between parasite-stress and religiosity. The discovery of novel microorganisms that affect host behavior may improve our understanding of neurobiology and neurochemistry, while the diversity of such organisms may be of interest to evolutionary biologists and religious scholars.

Reviewers

This article was reviewed by Prof. Dan Graur, Dr. Rob Knight and Dr. Eugene Koonin

Magnetic resonance imaging in neurocysticercosis

Cysticercosis in one of the most common parasitic infections in the central nervous system. The complex and unpredictable nature of the host immune reaction against cysticercosis as well as the pleomorphism of your injuries make the disease neurocysticercosis interesting and fascinating to study. Imaging studies play an important role in the diagnosis of this disease. Advanced imaging techniques have improved detection and visualization of scolex cysts extraparenchymal spaces.

Neurological and ocular fascioliasis in humans

Fascioliasis is a food-borne parasitic disease caused by the trematode species Fasciola hepatica, distributed worldwide, and Fasciola gigantica, restricted to given regions of Africa and Asia. This disease in humans shows an increasing importance, which relies on its recent widespread emergence related to climate and global changes and also on its pathogenicity in the invasive, biliary, and advanced chronic phases in the human endemic areas, mainly of developing countries. In spite of the large neurological affection capacity of Fasciola, this important pathogenic aspect of the disease has been pronouncedly overlooked in the past decades and has not even appear within the numerous reviews on the parasitic diseases of the central nervous system. The aim of this wide retrospective review is an in-depth analysis of the characteristics of neurological and ocular fascioliasis caused by these two fasciolid species. The terms of neurofascioliasis and ophthalmofascioliasis are restricted to cases in which the direct affection of the central nervous system or the eye by a migrant ectopic fasciolid fluke is demonstrated by an aetiological diagnosis of recovered flukes after surgery or spontaneous moving-out of the fluke through the orbit. Cases in which the ectopic fluke is not recovered and the symptoms cannot be explained by an indirect affection at distance may also be included in these terms. Neurofascioliasis and ophthalmofascioliasis cases are reviewed and discussed. With regard to fascioliasis infection giving an indirect rise to neurological affection, the distribution and frequency of cases are analysed according to geography, sex, and age. Minor symptoms and major manifestations are discussed. Three main types of cases are distinguished depending on the characteristics of their manifestations: genuine neurological, meningeal, and psychiatric or neuropsychic. The impressive symptoms and signs appearing in each type of these cases are included. Brain examination techniques and neuroimaging useful for the diagnosis of neurological cases are exposed. Within fascioliasis infection indirectly causing ocular manifestations, case distribution and frequency are similarly analysed. A short analysis is devoted to clarify the first reports of a human eye infection. The affection of related and close organs is discussed by differentiating between cases of the dorsal spine, pulmonary manifestations, heart and vessel affection, findings in blood vessels, skin and dermatologic reactions, cases of ectopic mature flukes, and upper body locations. The clinical complexity of the puzzling polymorphisms, the disconcerting multifocality of the manifestations, and their changes along the evolution of the disease in the same patient, as well as the differences between the clinical pictures shown by different patients, are highlighted. The many syndromes involved are enumerated. The pathogenic and physiological mechanisms underlying neurofascioliasis and ophthalmofascioliasis caused by ectopic flukes and the physiopathogenic processes indirectly affecting the central nervous system and causing genuine neurological, meningeal, psychiatric, and ocular manifestations are discussed. The diagnosis of neurological and ophthalmologic fascioliasis is analysed in depth, including clinical and paraclinical diagnosis, eosinophilia in the blood and cerebrospinal fluid, differential diagnosis from other parasitic infections such as helminthiases and myiases, an update of human fascioliasis diagnosis, and fluke and/or fluke egg recovery by surgery. Diagnostic analyses with faecal and blood samples for fascioliasis patients are updated. Therapy for patients with major neurological manifestations includes both antiparasitic treatments and anti-inflammatory therapeutics. Prognosis in fascioliasis patients with neurological manifestations is discussed, with emphasis on sequelae and fatal cases, and the care of patients with ophthalmologic manifestations is added. Conclusions indicate that neurological cases are overlooked in human fascioliasis endemic areas and also in developing countries in general. In remote zones, rural health centres and small hospitals in or near the human endemic areas do not dispose of the appropriate equipments for neurological analyses. Moreover, physicians may not be aware about the potential relationship between liver fluke infection and neurological implications, and such cases may therefore remain misdiagnosed, even in developed countries. Priority should henceforth be given to the consideration of neurological and ocular affection in human endemic areas, and efforts should be implemented to assess their characteristics and frequency. Their impact should also be considered when estimating the global burden of fascioliasis.

Brain abscess: Current management

Brain abscess (BA) is defined as a focal infection within the brain parenchyma, which starts as a localized area of cerebritis, which is subsequently converted into a collection of pus within a well-vascularized capsule. BA must be differentiated from parameningeal infections, including epidural abscess and subdural empyema. The BA is a challenge for the neurosurgeon because it is needed good clinical, pharmacological, and surgical skills for providing good clinical outcomes and prognosis to BA patients. Considered an infrequent brain infection, BA could be a devastator entity that easily left the patient into dead. The aim of this work is to review the current concepts regarding epidemiology, pathophysiology, etiology, clinical presentation, diagnosis, and management of BA.

Intracranial cysts: an imagery diagnostic challenge

Intracerebral cysts and cystic appearing intracerebral masses are common findings at routine cerebral imaging examination. We discuss here the most interesting aspects of some intracerebral cysts encountered in medical practice in terms of imaging, clinical and pathological description, and problems of differential diagnosis. On an almost routine basis, the neurologists have to deal with such differentials. Therefore, we aim to mention here some of the frequently encountered diagnosis problems when a patient presents with a cystic cerebral mass.

Contrast-enhanced ultrasonographic findings of hepatic paragonimiasis

AIM: To investigate the features of hepatic paragonimiasis on contrast-enhanced ultrasound (CEUS) imaging.

METHODS: Fifteen patients with hepatic paragonimiasis who were admitted to our hospital between March 2008 and August 2012 were enrolled to this study. The conventional ultrasound and CEUS examinations were performed with a Philips IU22 scanner with a 1-5-MHz convex transducer. After conventional ultrasound scanning was completed, the CEUS study was performed. Pulse inversion harmonic imaging was used for CEUS. A bolus injection of 2.4 mL of a sulfur hexafluoride-filled microbubble contrast agent (SonoVue) was administered. CEUS features were retrospectively reviewed and correlated with pathological findings.

RESULTS: In total, 16 lesions were detected on CEUS. The mean size of the lesions was 4.4 ± 1.6 cm (range, 1.7-6.6 cm). Subcapsular location was found in 12 lesions (75%). All the lesions were hypoechoic. Six lesions (37.5%) were of mixed content, seven (43.8%) were solid with small cystic areas, and the other three (18.8%) were completely solid. Ten lesions (62.5%) were rim enhanced with irregular tract-like nonenhanced internal areas. Transient wedge-shaped hyperenhancement of the surrounding liver parenchyma was seen in seven lesions (43.8%). Areas with hyper- or iso-enhancement in the arterial phase showed contrast wash-out and appeared hypoenhanced in the late phase. The main pathological findings included: (1) coagulative or liquefactive necrosis within the lesion, infiltration of a large number of eosinophils with the formation of chronic eosinophilic abscesses and sporadic distribution of Charcot-Leyden crystals; and (2) hyperplasia of granulomatous and fibrous tissue around the lesion.

CONCLUSION: Subcapsular location, hypoechogenicity, rim enhancement and tract-like nonenhanced areas could be seen as the main CEUS features of hepatic paragonimiasis.

Imaging of small-animal models of infectious diseases

Infectious diseases are the second leading cause of death worldwide. Noninvasive small-animal imaging has become an important research tool for preclinical studies of infectious diseases. Imaging studies permit enhanced information through longitudinal studies of the same animal during the infection. Herein, we briefly review recent studies of animal models of infectious disease that have used imaging modalities.

Parasitoses of the human central nervous system

Cerebral involvement in parasitoses is an important clinical manifestation of most of the human parasitoses. Parasites that have been described to affect the central nervous system (CNS), either as the dominant or as a collateral feature, include cestodes (Taenia solium (neurocysticerciasis), Echinococcus granulosus (cerebral cystic echinococcosis), E. multilocularis (cerebral alveolar echinococcosis), Spirometra mansoni (neurosparganosis)), nematodes (Toxocara canis and T. cati (neurotoxocariasis), Trichinella spiralis (neurotrichinelliasis), Angiostrongylus cantonensis and A. costaricensis (neuroangiostrongyliasis), Gnathostoma spinigerum (gnathostomiasis)), trematodes (Schistosoma mansoni (cerebral bilharziosis), Paragonimus westermani (neuroparagonimiasis)), or protozoa (Toxoplasma gondii (neurotoxoplasmosis), Acanthamoeba spp. or Balamuthia mandrillaris (granulomatous amoebic encephalitis), Naegleria (primary amoebic meningo-encephalitis), Entamoeba histolytica (brain abscess), Plasmodium falciparum (cerebral malaria), Trypanosoma brucei gambiense/rhodesiense (sleeping sickness) or Trypanosoma cruzi (cerebral Chagas disease)). Adults or larvae of helminths or protozoa enter the CNS and cause meningitis, encephalitis, ventriculitis, myelitis, ischaemic stroke, bleeding, venous thrombosis or cerebral abscess, clinically manifesting as headache, epilepsy, weakness, cognitive decline, impaired consciousness, confusion, coma or focal neurological deficits. Diagnosis of cerebral parasitoses is dependent on the causative agent. Available diagnostic tools include clinical presentation, blood tests (eosinophilia, plasmodia in blood smear, antibodies against the parasite), cerebrospinal fluid (CSF) investigations, imaging findings and occasionally cerebral biopsy. Treatment relies on drugs and sometimes surgery. Outcome of cerebral parasitoses is highly variable, depending on the effect of drugs, whether they are self-limiting (e.g. Angiostrongylus costaricensis) or whether they remain undetected or asymptomatic, like 25% of neurocysticerciasis cases.

Reduced diffusion in neurocysticercosis: circumstances of appearance and possible natural history implications

BACKGROUND AND PURPOSE

Few studies discuss DWI findings in patients with NCC, and their conclusions are variable and contradictory. The aim of our study was to describe DWI findings of a cohort of patients with NCC, emphasizing the frequency of reduced diffusion.

MATERIALS AND METHODS

This retrospective study included 48 patients with NCC. Two neuroradiologists analyzed MR images regarding location, number, and stage of NCC lesions. On the basis of visual analysis, they defined, by consensus, the presence of high signal within NCC lesions on DWI and measured their ADC values when feasible.

RESULTS

The total number of lesions was 342: parenchymal (263), subarachnoid (65), and intraventricular (14); 83 were DWI hyperintense. The first pattern was a small eccentric hyperintense dot/curvilinear structure on DWI (representing the scolex) noted in intraparenchymal lesions in vesicular (41 lesions, 29%) and colloidal vesicular (18 lesions, 19%) stages, in 14 (22%) subarachnoid lesions, and 2 (14%) intraventricular lesions; rADC calculations were hampered by the intrinsic small dimensions of this finding. The second pattern was the presence of total/subtotal DWI hyperintensity in intraparenchymal lesions, 5 in the colloidal vesicular stage (5%) and 1 in the granular nodular phase (3%). Two subarachnoid lesions also showed the same presentation; in this second pattern, reduced diffusion was present in different degrees, measured by rADC calculations.

CONCLUSIONS

DWI may identify the scolex, increasing diagnostic confidence for NCC. Total/subtotal DWI hyperintensity, related to the stage of the lesion, though uncommon, allows including NCC as a consideration in the differential diagnosis of lesions with reduced diffusion and ring enhancement.