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Infection-Associated Ocular Cranial Nerve Palsies
Published in Vivek Lal, A Clinical Approach to Neuro-Ophthalmic Disorders, 2023
Hardeep Singh Malhotra, Imran Rizvi, Neeraj Kumar, Kiran Preet Malhotra, Gaurav Kumar, Manoj K. Goyal, Manish Modi, Ravindra Kumar Garg, Vivek Lal
Enzyme-linked immunotransfer blot has been recommended over enzyme-linked immunosorbent assays (using crude antigen) for the diagnosis of patients suspected of NCC (37). Well-defined cystic lesion with a scolex is often visible, pending degeneration, on CT, MRI, or USG. The muscle containing the cyst is enlarged and may show signs of inflammation. MRI of orbits may show diffuse muscle enlargement with signs of soft tissue inflammation (Figure 16.14). MRI of the brain may reveal NCC in various stages of evolution, in addition to ocular lesions. The presence of a cystic lesion differentiates the condition from other differentials like thyroid ophthalmopathy.
The Parasitic Protozoa and Helminth Worms
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
Upon ingestion of uncooked, infected pork by humans, the bladder of the cysticer-cus is digested away, and the scolex attaches to the intestine wall where it develops into an adult worm. Regardless of the number of cysticerci ingested, an individual almost always harbors only one adult worm in the intestine; the reason is not known. Most infected individuals exhibit no symptoms and may be unaware of the presence of the worm. However, if a human ingests the eggs these can hatch and develop into cysticerci throughout the body. These eventually degenerate and calcify but if located in the brain or other vital organ, they can cause severe disease or death. Very little is known about immunity to the adult stages of T. solium in humans although spontaneous recoveries have been recorded. It is thought that there might be some concomitant immunity directed against the invading larval stages. The cysticerci, on the other hand, do elicit immune responses characterized by the production of specific antibodies and cellular responses. How the parasites survive immune attack is not known.
Candida and parasitic infection: Helminths, trichomoniasis, lice, scabies, and malaria
Published in Hung N. Winn, Frank A. Chervenak, Roberto Romero, Clinical Maternal-Fetal Medicine Online, 2021
All helminths are classified as Platyhelminthes (flatworms) or Nematoda (roundworms). Flatworms are further divided into cestodes and trematodes (Table 2). Cestodes, or tapeworms, have segmented bodies consisting of proglottids attached via the neck zone to a head or scolex. The scolex provides attachment and locomotion via grooves, suckers, and hooks extending from its surface (Fig. 1). Tapeworms are hermaphroditic, with both male and female reproductive organs contained in each segment. There is no organized digestive tract; nutrients are absorbed via the integument. Excretory and nervous systems are present, but only in primitive form (31).
Imaging of infectious and inflammatory cystic lesions of the brain, a narrative review
Published in Expert Review of Neurotherapeutics, 2023
Anna Cervantes-Arslanian, Hector H Garcia, Otto Rapalino
Imaging in NCC varies depending upon life cycle of the organism and host response (Figures 3 and Figure 4). Once T. solium embryos invade the human brain, they establish as viable, non-enhancing cysts (vesicular stage), and fully-grown cysts form three to four months after infection. CT may show small cysts with thin smooth walls with up to half demonstrating a scolex within (mural nodule that appears as a hole with a dot) [21]. MR demonstrates cysts with well-defined thin walls with little or no enhancement. A scolex may be visible within the cysts. Cysts signal intensity are isointense to CSF on T1 and T2, T1 iso to hypointense and T2 iso- to hyperintense relative to white matter. Cysts typically do not show DWI restriction and have high ADC signal [1].
Inflammation in neurocysticercosis: clinical relevance and impact on treatment decisions
Published in Expert Review of Anti-infective Therapy, 2021
Pedro T Hamamoto Filho, Gladis Fragoso, Edda Sciutto, Agnès Fleury
The factors underlying the development of this edema are still unclear. It is feasible that although the parasite looks calcified, parasite antigens or genetic material are still present and elicit some degree of local inflammation by the host [61]. In this context, the histopathologic characteristics of calcification with perilesional edema surgically excised in a patient with refractory epilepsy are interesting [80]. A marked mononuclear infiltrate in the capsule around the calcified cysticerci and extending to the adjacent brain was found, in clear contrast with the classic description of cysticercal calcification, in which the capsule is fibrous without noticeable inflammation [43]. It is also relevant to note that the presence of scolex remnants within the calcified lesion was significantly more frequently observed in calcifications associated with edema than in calcified lesions without edema [81]. The presence of scolex remnants in certain parasites could probably be interpreted as incomplete degradation of the parasite with preservation of certain antigenic components [81] and would be in accordance with the inflammatory hypothesis.
Orbital cysticercosis: clinical features and management outcomes
Published in Orbit, 2021
Shebin Salim, Md Shahid Alam, Varsha Backiavathy, Nirav Dilip Raichura, Bipasha Mukherjee
The characteristic appearance of a live cyst in the USG B scan is a well-defined lesion having clear contents, and a high-reflective echo dense nodule within, suggestive of the scolex.6 CT scan shows a hypodense lesion with a central hyperdensity suggestive of the scolex. MRI reveals a hypointense cystic lesion and hyperintense scolex.13The scolex is not seen if the parasite is dead or the cyst is ruptured. The imaging features may change as the disease progresses with less prominent scolex, features of variable orbital inflammation, and thickening of the extraocular muscles.6 Lack of characteristic features can result in misdiagnosis by radiologists unfamiliar with orbital imaging. Many of the study patients had received a course of albendazole elsewhere with resultant death of the cyst; this along with the delayed presentation could explain the absence of scolex in imaging in 13 (21.31%) patients. The possibility of seeing a definite cyst with scolex on imaging is around 50%.6 In our study, definite scolex was seen in 48 patients (78.69%).