Visceral larva migrans presenting as multiple intracranial and intraspinal abscesses

Involvement of nervous system by toxocariasis is rare and can produce a spectrum of pathology that includes eosinophillic meningoencephalitis, meningomyelitis, space occupying lesions, vasculitis causing seizures or behavioral abnormalities posing diagnostic dilemmas. We describe a 38-year-old man who presented with multiple intracranial and intramedullary abscesses caused by visceral larva migrans. Neurohelminthiasis as a cause of multiple abscesses, though rare, should be entertained as a differential diagnosis particularly in tropical South-east Asian countries where helminthiasis is still an epidemiological concern prevalent in the pediatric age group.

Cestode parasitic infestation: intracranial and spinal hydatid disease--a clinicopathological study of 29 cases from South India

In developing countries hydatidosis is both a medical and economic problem related to environmental hygiene and healthy veterinary practice. This cestode parasitic infestation, uncommonly involving the nervous system, presents with varied clinical manifestation, at times causing diagnostic dilemmas. Multiple intracranial and spinal hydatidosis is rare. A series of 29 histologically confirmed cases of hydatidosis of neuraxis (21 intracranial and 8 spinal) from South India are presented. Among the 21 cases of intracranial hydatidosis, 12 cases were in pediatric age, while only 1 spinal lesion was noted in a 5-year-old child. The clinical presentation of intracranial lesions was predominantly that of raised intracranial pressure and visual symptoms, while spinal hydatidosis manifested with severe back pain, weakness and sphincter disturbances. The cranial cysts were usually single and uniloculated (12 cases), multiple in 7 and single but multiloculated in 2. In spinal hydatidosis, the cysts are usually multiple and extradural, rare ones being intramedullary and intradural. Based on clinical features and imaging, the differential diagnosis for intracranial lesions were cystic tumors and arachnoid cyst while metastasis and tuberculosis were considered in cases of spinal hydatidosis because of vertebral bony involvement. The majority of the cysts could be surgically resected totally and some were aspirated under control suction and resected. None of the cases had anaphylactic reaction, with no significant post-operative morbidity and no mortality. One intracranial and 2 spinal lesions caused by fertile cysts recurred to undergo repeated surgery.

Balamuthia mandrillaris, an opportunistic agent of granulomatous amebic encephalitis, infects the brain via the olfactory nerve pathway

Balamuthia mandrillaris is a free-living ameba and an opportunistic agent of lethal granulomatous amebic encephalitis (GAE) in humans and other mammals. Its supposed routes of infection have been largely assumed from what is known about Acanthamoeba spp. and Naegleria fowleri, other free-living amebae and opportunistic encephalitis agents. However, formal proof for any migratory pathway, from GAE patients or from animal models, has been lacking. Here, immunodeficient mice were infected with B. mandrillaris amebae by intranasal instillation, the most likely natural portal of entry. By means of classical and immunohistology, the amebae are shown to adhere to the nasal epithelium, progress along the olfactory nerves, traverse the cribriform plate of the ethmoid bone, and finally infect the brain. A similar invasion pathway has been described for N. fowleri. The data suggest that the olfactory nerve pathway is a likely route for natural infection of the brain by B. mandrillaris amebae.

[Cerebrovascular disease in the tropics]

OBJECTIVES

To review the clinical manifestations, diagnosis, and therapy of diseases causing cerebrovascular disease (CVD) in the tropics.

DEVELOPMENT

Most prevalent conditions causing CVD in the tropics include: sickle cell disease, Takayasu s arteritis, cysticercosis, infective endocarditis, Chagas disease, viral hemorrhagic fevers, gnathostomiasis, leptospirosis, snake bites, cerebral malaria, puerperal venous thrombosis, and tuberculosis. These conditions may cause cerebral infarcts or hemorrhages, and in most instances are related to either vascular damage secondary to angiitis or hemorrhagic diathesis with bleeding in other organs. In some patients, the severity of the neurological picture makes impossible to identify an specific stroke syndrome and cerebrovascular complications are only recognized on neuroimaging studies or autopsy.

CONCLUSIONS

There is a group of tropical infectious and non infectious diseases that may cause cerebral infarcts or hemorrhages. Prompt diagnosis and therapy are needed to reduce the severity or brain damage and to avoid recurrent strokes.

Infection of organotypic slice cultures from rat central nervous tissue with Trypanosoma brucei brucei

We recently described a new procedure to grow nervous tissue as organotypic culture. The main feature of these slice cultures is to maintain a well preserved, three-dimensional organisation of the central nervous tissue. As these cultures can be kept for several weeks (up to three months), we have used this in vitro approach to study the complex interactions between host tissue and parasites during late stages of cerebral African trypanosomiasis. Light and electron microscopical studies, as well as electrophysiological recordings demonstrate that the structure and function of the nervous tissue is not severely affected even after several weeks of trypanosome infection. The presence of a large number of parasites does not seem to be deleterious to neuronal survival. Secondly, most of the trypanosomes are located around the periphery of the nervous tissue, but many of them also penetrate into the nervous parenchyma. Thirdly, trypanosomes with well-conserved morphology are found within the cytoplasm of glial cells, which in some cases were identified as astrocytes. These "intracellular parasites" seem to actively invade the target cells. Our study demonstrates that the presence of proliferating trypanosomes does not per se interfere with the neural activity of CNS tissues. Secondly, it provides, to the best of our knowledge, the first in vitro demonstration of intracellular forms of African trypanosomes.