Central nervous system infections

Chronic Cerebellar Meningoencephalitis in Adulthood: A Report of a Rare Case

The development of meningoencephalitis is a result of an inflammation of the meninges and the brain, which can cause neurological sequelae. Cerebellar meningoencephalitis in adult patients is extremely rare and requires special diagnostic approaches. The aim of this report is to present a rare case of meningoencephalitis and evaluate the diagnostic and therapeutic techniques. We present a 45-year-old male patient who has entered the neurosurgery clinic with a severe headache lasting for a month. Neurological status determines intracranial hypertension. Magnetic resonance tomography (MRT) showed evidence of hyperintense lesions with homogenous enhancement in the right hemisphere of the cerebellum. The patient underwent a suboccipital paramedian craniotomy to excise the lesions and for the pathohistological examination of the biopsy material. Biopsy examination found sections expressing an infection process causing chronic meningoencephalitis in the right hemisphere of the cerebellum. The patient was treated postoperatively with cephalothin 2 g every 12 hours for 14 days. Follow-up examinations proved a relief of the symptoms. Meningoencephalitis of the cerebellum and the meninges is a complication that may occur in adulthood, and surgical excision, biopsy examination, and antibiotic therapy are promising methods for managing the disease.

['Masks' of acute neuroinfections and markers of differencial diagnosis]

AIM

To compare thе medical history, clinical features, composition of cerebrospinal fluid (CSF), results of laboratory and instrumental examinations of patients with acute neuroinfections and differentiable diseases including a pseudoinflammatory variant of the acute stage of uncomplicated subarachnoid hemorrhage (SAH), consequences of traumatic brain injury (traumatic SAH, SAN combination with secondary purulent meningitis, posttraumatic nasal liquorrhea, intracerebral hematomas), abscesses and tumors of the brain, lymphoma with proven CNS. These diagnoses were mistakenly made to patients admitted to an infectious department.

MATERIAL AND METHODS

Forty-six patients, aged from 18 to 83 years, hospitalized in the Department of neuroinfections and intensive care in 2010-2016 were examined. Conventional clinical neurological, laboratory, instrumental (including MRI) examinations of patients, comprehensive examination of CSF samples, the study of markers of inflammation (C - reactive protein, CSF lactate), immunophenotyping of CSF cells were performed.

RESULTS AND CONCLUSION

The misdiagnosis can be explained by the overestimation of such symptoms as the acute (in most cases) onset of the disease with increased body temperature to febrile levels, presence of meningeal syndrome, disorders of consciousness and focal symptoms of varying severity. The authors showed the errors and difficulties in the diagnosis, the role and importance of an integrated, interdisciplinary approach taking into account history, clinical data, results of CSF study, conventional and special methods of laboratory and instrumental examination of patients.

The Etiological Spectrum of Febrile Encephalopathy in Adult Patients: A Cross-Sectional Study from a Developing Country

The profile of febrile encephalopathy varies based on different demographic and geographical characteristics of the study population. This retrospective, cross-sectional study was conducted to evaluate the etiological spectrum of febrile encephalopathy in hospitalized adult patients. A total of 293 patients with the mean age of 49.7 ± 23 were evaluated of whom 77.1% presented with encephalopathy syndrome. The most common diagnosis in patients with clinical syndromes suggestive of central nervous system (CNS) infection was sepsis associated encephalopathy (SAE) (22.9%), followed by bacterial meningitis (14%) and neurotuberculosis (9.9%). The comparison between the elderly and young adults showed that, in the young adults, bacterial meningitis and neurotuberculosis, and in the elderly SAE, are among the most common causes of clinical syndromes suggestive of CNS infection including febrile encephalopathy in our region. Moreover, we illustrated an upward trend for the proportion of diagnosing CNS infections among those who underwent diagnostic LP, from 40.4% in 2011 to 70% in 2015, that could be indicative of an increasing threshold for performing LP at least in our center in recent years. Whether these changes have been associated with increasing the rate of diagnostic errors or not needs to be evaluated in future studies.

Neuroimaging in Central Nervous System Infections

Radiologic imaging is often employed to supplement clinical evaluation in cases of suspected central nervous system (CNS) infection. While computed tomography (CT) is superior for evaluating osseous integrity, demineralization, and erosive changes and may be more readily available at many institutions, magnetic resonance imaging (MRI) has significantly greater sensitivity for evaluating the cerebral parenchyma, cord, and marrow for early changes that have not yet reached the threshold for CT detection. For these reasons, MRI is generally superior to CT for characterizing bacterial, viral, fungal, and parasitic infections of the CNS. The typical imaging features of common and uncommon CNS infectious processes are reviewed.

Magnetic resonance imaging of infectious meningitis and ventriculitis in adults

Magnetic resonance imaging findings of meningitis are usually nonspecific with respect to the causative pathogen because the brain response to these insults is similar in most cases. In this article, we will use a few representative cases to describe the characteristic magnetic resonance findings of meningitis and its complications, including ventriculitis.

Magnetic resonance imaging in viral and prion diseases of the central nervous system

The early detection and specific diagnosis of viral infections of the central nervous system are important because many of these diseases are potentially treatable. However, clinical symptoms and physical examination are often nonspecific, and rapid diagnostic tests are available for some, but not all, viruses. Neuroimaging, in conjunction with clinical history and laboratory tests, plays an important role in narrowing the differential diagnoses. In this article, we review the clinical features, imaging characteristics, diagnosis, and treatment of the more common viral infections and prions that involve the central nervous system.

The role of dynamic susceptibility contrast-enhanced perfusion MR imaging in differentiating between infectious and neoplastic focal brain lesions: results from a cohort of 100 consecutive patients

Background and Purpose

Differentiating between infectious and neoplastic focal brain lesions that are detected by conventional structural magnetic resonance imaging (MRI) may be a challenge in routine practice. Brain perfusion-weighted MRI (PWI) may be employed as a complementary non-invasive tool, providing relevant data on hemodynamic parameters, such as the degree of angiogenesis of lesions. We aimed to employ dynamic susceptibility contrast-enhanced perfusion MR imaging (DSC-MRI) to differentiate between infectious and neoplastic brain lesions by investigating brain microcirculation changes.

Materials and Methods

DSC-MRI perfusion studies of one hundred consecutive patients with non-cortical neoplastic (n = 54) and infectious (n = 46) lesions were retrospectively assessed. MRI examinations were performed using a 1.5-T scanner. A preload of paramagnetic contrast agent (gadolinium) was administered 30 seconds before acquisition of dynamic images, followed by a standard dose 10 seconds after starting imaging acquisitions. The relative cerebral blood volume (rCBV) values were determined by calculating the regional cerebral blood volume in the solid areas of lesions, normalized to that of the contralateral normal-appearing white matter. Discriminant analyses were performed to determine the cutoff point of rCBV values that would allow the differentiation of neoplastic from infectious lesions and to assess the corresponding diagnostic performance of rCBV when using this cutoff value.

Results

Neoplastic lesions had higher rCBV values (4.28±2.11) than infectious lesions (0.63±0.49) (p<0.001). When using an rCBV value <1.3 as the parameter to define infectious lesions, the sensitivity of the method was 97.8% and the specificity was 92.6%, with a positive predictive value of 91.8%, a negative predictive value of 98.0%, and an accuracy of 95.0%.

Conclusion

PWI is a useful complementary tool in distinguishing between infectious and neoplastic brain lesions; an elevated discriminatory value for diagnosis of infectious brain lesions was observed in this sample of patients when the rCBV cutoff value was set to 1.3.

Imaging of central nervous system viral diseases

Viral infections of the central nervous system (CNS) are commonly encountered and there has been continued emergence of new neurotropic viruses which are being frequently recognized. These may present clinically as encephalitis, meningitis, encephalomyelitis, and encephalomyeloradiculitis. The clinical manifestations are usually nonspecific and diagnosis is usually based on the laboratory investigations. Imaging plays a role in its early detection and at times suggests the specific diagnosis that may help in early institution of appropriate therapy. In this review, we summarize the pathology, clinical, and imaging features of the common viral infections that affect the CNS.

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.

Eccentric target sign in cerebral toxoplasmosis: neuropathological correlate to the imaging feature

Cerebral toxoplasmosis remains one of the most common focal brain lesions in patients with acquired immune deficiency syndrome (AIDS). Diagnosis is a challenge because on cranial imaging it closely mimics central nervous system lymphoma, primary and metastatic central nervous system (CNS) tumors, or other intracranial infections like tuberculoma or abscesses. A magnetic resonance imaging (MRI) feature on postcontrast T1-weighted sequences considered pathognomonic of toxoplasmosis is the "eccentric target sign." The pathological correlate of this imaging sign has been speculative. Herein we correlate the underlying histopathology to the MR feature of eccentric target sign in a patient with autopsy-proven HIV/AIDS-related cerebral toxoplasmosis. The central enhancing core of the target seen on MRI was produced by a leash of inflamed vessels extending down the length of the sulcus that was surrounded by concentric zones of necrosis and a wall composed of histiocytes and proliferating blood vessels, with impaired permeability producing the peripheral enhancing rim.

Neurological complications

Patients with neurological malignancies are subject to developing a unique set of complications that require emergent evaluation and treatment. With the increasing incidence of cancer in the general population and improved survival, these emergencies will be more frequently encountered. Physicians must be able to recognize these conditions and institute appropriate therapy after a focused initial evaluation. The approach to definitive therapy is commonly multidisciplinary, involving surgeons, radiation oncologists, medical oncologists, and other medical specialists. Prompt interventions can be lifesaving and may spare patients considerable morbidity and pain. In neuro-oncology, there are some more specific complications and emergencies. The more general complications are not reviewed here.