Successful medical management of a Nocardia farcinica multiloculated pontine abscess.

A 60-year-old man on chronic corticosteroids developed diplopia, gait instability and facial weakness. Brain MRI revealed a multiloculated pontine lesion. Cerebrospinal fluid (CSF) analysis demonstrated a neutrophil-predominant pleocytosis with elevated protein and low glucose. CSF cultures were negative, as was an extensive infectious diseases evaluation. Neurosurgical intervention was deferred in favour of empiric antimicrobial therapy due to the lesion's inaccessible location. After discontinuation of therapy, the patient reported a severe headache. A subsequent MRI demonstrated intraventricular pus. CSF culture grew Nocardia farcinica. The patient received parenteral therapy followed by oral trimethoprim-sulfamethoxazole. At 9 months, he is symptom free. This case illustrates the importance of including Nocardia in the differential diagnosis of brainstem abscesses, especially in immunocompromised patients. The availability of antimicrobial agents with excellent Nocardia activity and CSF penetration may enable treatment of brainstem abscesses for which surgical intervention has traditionally been considered necessary with medical management alone.

Incidental MRI finding of a pons tuberculoma in a patient with so-far-undiagnosed multisystemic tuberculosis infection.

Tuberculomas are routinely included in the differential diagnosis of newly detected intracranial lesions in patients with known systemic tuberculosis, but are rarely considered in patients without systemic disease. We report a 49-year-old patient without any neurological symptoms whose magnetic resonance imaging examination showed a lesion in the pons that was suspected of being an opportunistic, DD granulomatous lesion, which prompted further laboratory examinations revealing systemic tubercle bacillus (TB) infection. Tuberculosis should be included in the differential diagnosis of an intracranial solitary lesion even in atypical locations and in asymptomatic patients without prior diagnosis of a TB.

Isolated pontine tuberculoma presenting as "fou rire prodromique".

The authors present the case of a young child with "fou rire prodromique" as an initial manifestation of pontine tuberculoma. This report is the first description of fou rire prodromique as the presenting sign of CNS tuberculosis. The combination of clinical information and CT findings allowed for precise localization of the lesion and suggested tuberculoma as the possible etiology.

Pontocerebellar angle aspergillosis: clinical and radiological findings.

INTRODUCTION: Cerebral aspergillosis is a rare and severe condition mostly affecting immunocompromised patients. The lesions are usually intra-axial and supratentorial; several radiologic patterns have been reported. CASE REPORT: A 65-year-old patient with chronic lymphocytic leukemia presented with fever, headache, and a pontocerebellar syndrome. A brain magnetic resonance imaging (MRI) showed a ring-enhancing left pontocerebellar mass consistent with an infectious disease. Despite broad-spectrum antibiotic therapy, the patient worsened. A follow-up MRI examination disclosed a concomitant acute ischemic lesion in the ipsilateral thalamus and an irregular narrowing of the posterior cerebral artery close to the lesion. A retrospective analysis of the first MRI revealed a small mesencephalic ischemic lesion, contiguous to the extra-axial pontocerebellar mass. At surgical inspection the mass was found to be an extra-axial granuloma, with purulent components, attached to the petrous-tentorial angle, surrounded by a thick capsule. The lesion was only partially removed because of the tight relationship with the leptomeninges of the brain stem. Cerebral aspergillosis was the final histologic and microbiological diagnosis. CONCLUSION: In immunocompromised patients, the coexistence of an infectious lesion with involvement of contiguous vessels and consequent ischemic infarction should raise the suspicion of aspergillosis, even in unusual locations such as the pontocerebellar angle.

Pontine tuberculoma presenting with horizontal gaze palsy.

A 38-year-old immunocompetent man presented with a horizontal supranuclear gaze palsy as the only neurologic manifestation of a pontine tuberculoma. Although a biopsy of the brain lesion was not performed, it was attributed to tuberculosis because of chest x-ray evidence. The patient was given empirical anti-tuberculous therapy. After one month, the gaze palsy had fully recovered and repeat MRI showed a decrease in the size of the lesion. This is the first reported case of supranuclear gaze palsy without diplopia as a manifestation of a tuberculous brain stem lesion.

Trigeminal neuralgia caused by a pontine abscess: case report.

OBJECTIVE AND IMPORTANCE: Various intracranial abnormalities, including infectious conditions, may manifest as trigeminal neuralgia. CLINICAL PRESENTATION: A 33-year-old man presented with a 15-day history of right-sided facial pain and numbness. Neurological examination revealed diminished corneal reflex and facial sensation in the right V(1)-V(2) distribution. Magnetic resonance imaging revealed a contrast-enhancing lesion centered at the right pons with extension of the enhancement to the sphenoid sinus. INTERVENTION: Broad-spectrum antibiotics were administered for 6 weeks. This resulted in alleviation of symptoms and resolution of the lesion as revealed by repeat magnetic resonance imaging. CONCLUSION: Presentation of a pons abscess with trigeminal neuralgia is rare, and to the best of our knowledge has not been reported previously. The patient was treated successfully with antibiotics alone.

Molecular and immunological evidence of oral Treponema in the human brain and their association with Alzheimer's disease.

The purpose of this investigation was to use molecular and immunological techniques to determine whether oral Treponema infected the human brain. Pieces of frontal lobe cortex from 34 subjects were analyzed with species-specific PCR and monoclonal antibodies. PCR detected Treponema in 14/16 Alzheimer's disease (AD) and 4/18 non-AD donors (P < 0.001), and AD specimens had more Treponema species than controls (P < 0.001). PCR also detected Treponema in trigeminal ganglia from three AD and two control donors. Cortex from 15/16 AD subjects and 6/18 controls contained Treponema pectinovorum and/or Treponema socranskii species-specific antigens (P < 0.01). T. pectinovorum and/or T. socranskii antigens were also found in trigeminal ganglia and pons from four embalmed cadavers, and 2/4 cadavers also had Treponema in the hippocampus. These findings suggest that oral Treponema may infect the brain via branches of the trigeminal nerve.

Pontine cryptococcoma in a nonimmunocompromised individual: MRI characteristics.

The case of a pontine cryptococcoma in a nonimmunocompromised, previously healthy 16-year-old boy is presented. The patient had slowly progressive brainstem signs with right cranial nerves V, VII, and VIII palsies, and contralateral corticospinal and spinothalamic deficits. Magnetic resonance images (MRI) revealed, within the right pons, a 1-cm diameter round mass lesion, hypointense on T1-weighted images, hyperintense on T2-weighted images, and with rim enhancement after infusion of gadopentetate dimeglumine. This is the only report of the MRI findings in an isolated pontine cryptococcoma in an immunocompetent patient. Early recognition of this specific MRI pattern is essential, because complete recovery can be achieved with prompt antifungal treatment.

Acute disseminated encephalomyelitis following Pontiac fever.

We report the case of a 35-year-old woman who developed headache and psychosis and gradually became comatose within 3 weeks after a flu-like infection. MRI revealed bifrontal demyelination consistent with acute disseminating encephalomyelitis (ADEM). Two different cerebrospinal fluid samples were positively tested for Legionella cincinnatiensis by direct sequencing of a PCR-amplified Legionella-specific fragment. This result made it possible to interpret the initial symptoms as Pontiac fever. We think it most likely that this is a case of ADEM following the very rare situation of a systemic infection with L. cincinnatiensis. A review of the literature on Legionella-associated encephalopathy suggests that some of these cases may also have had ADEM.

Central nervous system innervation of the penis as revealed by the transneuronal transport of pseudorabies virus.

Transneuronal tracing techniques were used in order to identify putative spinal interneurons and brainstem sites involved in the control of penile function. Pseudorabies virus was injected into the corpus cavernosus tissue of the penis in rats. After a four day survival period, rats were perfused with fixative and virus-labelled neurons were identified by immunohistochemistry. Postganglionic neurons were retrogradely labelled in the major pelvic ganglia. In the spinal cord, sympathetic and parasympathetic preganglionic neurons were labelled transneuronally. Presumptive interneurons were also labelled in the lower thoracic and lumbosacral spinal cord in locations consistent with what is currently known about such interneurons. In the brainstem, transneuronally labelled neurons were found in the medulla, pons and hypothalamus. Regions consistently labelled included the nucleus paragigantocellularis, parapyramidal reticular formation of the medulla, raphe pallidus, raphe magnus, A5 noradrenergic cell group, Barrington's nucleus and the paraventricular nucleus of the hypothalamus. This study confirmed previous studies from our lab and others concerning the preganglionic and postganglionic neurons innervating the penis. The number, morphology and location of these neurons were consistent with labelling seen following injection of conventional tracers into the penis. The brainstem nuclei labelled in this study were also consistent with what is currently known about the brainstem control of penile function. The labelling appeared to be highly specific, in that descending systems involved in other functions were not labelled. These results provide further evidence that the pseudorabies virus transneuronal tracing technique is a valuable method for identifying neural circuits mediating specific functions.

Ultrastructural analysis of attachment to and penetration of capillaries in the murine pons, midbrain, thalamus, and hypothalamus by Nocardia asteroides.

The attachment to and penetration of endothelial cells in the pons and midbrain (especially the substantia nigra) regions of the brains of BALB/c mice by log-phase Nocardia asteroides GUH-2 cells were determined by both scanning and transmission electron microscopic analysis. Within 15 min after exposure, the nocardiae attached to the surface of the endothelial cell membrane. This attachment occurred primarily at the growing tip of the nocardial filament, and the outermost layer of the nocardial cell wall had regions (electron-dense areas) that bound firmly to the cytoplasmic membrane of the host cell. There appeared to be specificity for this binding localized within the capillaries and arterioles because some regions had large numbers of bacteria bound, whereas adjacent areas had no bacterial cells. Nocardial filaments that attached by the apex induced a cuplike deformation of the endothelial cell membrane. This was followed by a rapid penetration of the endothelial cell so that within 25 min many of the bacteria were internalized within the host cell. These internalized bacteria remained within vesicles, and there was no ultrastructural evidence of damage to the nocardial cell during this process. Heat-killed GUH-2 cells still attached to endothelial surfaces (at a reduced frequency), but they did not penetrate into the endothelial cell. These data suggest that brain-invasive nocardiae possess both an adhesin for attachment to the membrane of endothelial cells and an invasion factor that promotes nocardial penetration of these cells.

Acyclovir treatment of disseminated herpes simplex virus type 2 infection in weanling mice: alteration of mortality and pathogenesis.

Intranasal inoculation of weanling mice with herpes simplex virus type 2 (HSV-2) provides an experimental infection that closely resembles disseminated and central nervous system HSV infections of human neonates. Intraperitoneal treatment with acyclovir (ACV) successfully reduced mortality even when therapy was begun as late as 2 days and oral therapy as late as 4 days after viral challenge. Treatment with ACV beginning on day 1 completely inhibited HSV-2 replication in lung, spleen, kidney, olfactory lobe, and cerebrum and decreased viral titers in the pons by 2-3 logs. Comparison of these data with our previous experiments using adenine arabinoside and adenine arabinoside 5' monophosphate indicates that ACV is more effective in the murine model of neonatal disease and suggests that ACV may also be more effective in treating the disease in humans.

Autonomic nervous system involvement in experimental genital infection by herpes simplex virus type 2.

Peroxidase-antiperoxidase technique and histology were employed to elucidate the peripheral routes involved in HSV-2 progression from vagina towards the central nervous system in mice. 12 week-old female Balb/c mice were intravaginally infected with 5 X 10(5)LD50 of HSV-2. Sixty per cent of animals developed vulvovaginitis, perigenital alopecia and hind-limb paresia. Death occurred at 9-11 days post-infection. Colon dilatation and urinary bladder distention were observed in all cases. Complete transversal sections from vulva to kidneys were obtained of each animal, including the spinal cord in situ. Herpes antigen were regularly detected in vulvovaginal epithelium, intramural, perigenital and perivesical small nerves. Besides, their invariable presence in Auerbach's plexus and sympathetic ganglia, strongly suggests preferential autonomic nervous system involvement in the progression of HSV-2 intravaginal infection towards the spinal cord.

[Pontine histoplasmosis: report of a case]. / Histoplasmose pontina: registro de um caso.

A case of central nervous system histoplasmosis located at the pons is reported. The authors point out difficulties for the diagnosis of the pathology during life and some aspects of the treatment and their results. The rarity of the process is emphasized.

A low thymidine kinase-producing mutant of herpes simplex virus type 1 causes latent trigeminal ganglia infections in mice.

The wild type NIH strain of herpes simplex virus type 1 (HSV-1) has a mixed plaque morphology of both large and small plaques. From this virus we selected a large plaque isolate that was a high producer of thymidine kinase (TK) activity (designated TK+) and a small plaque isolate that produced 25 per cent of the TK activity of the large plaque mutant (designated TK 1/4). A TK- mutant of the large plaque virus was obtained after passage of the virus in the presence of BUdR. The pathogenicity of the TK 1/4 virus strain in relation to the TK+ and TK- strains was investigated in mice after inoculation of the virus into the eyes by corneal scarification. The TK+ strain was highly pathogenic, caused encephalitis and killed most of the mice, whereas the TK- strain did not cause latent infections in the trigeminal ganglia or kill the mice. The TK 1/4 virus strain replicated in the eyes within 24 hours after inoculation and entered the trigeminal ganglia, establishing a latent infection in almost all of the mice. By increasing the infectious dose tenfold, the TK 1/4 virus caused an active infection in the trigeminal ganglia (ganglionitis), migrated to the brain, and killed the mice. The results indicate that not only is a low level of TK required to establish latent infections in mice, but also the degree of virulence is determined by the amount of TK produced by the infecting virus.