Neuroradiology of infectious diseases.

PURPOSE OF REVIEW: Early diagnosis of central nervous system (CNS) infections is crucial given high morbidity and mortality. Neuroimaging in CNS infections is widely used to aid in the diagnosis, treatment and to assess the response to antibiotic and neurosurgical interventions. RECENT FINDINGS: The Infectious Diseases Society of America (IDSA) guidelines have clear recommendations for obtaining a computerized tomography of the head (CTH) prior to lumbar puncture (LP) in suspected meningitis. In the absence of indications for imaging or in aseptic meningitis, cranial imaging is of low utility. In contrast, cranial imaging is of utmost importance in the setting of encephalitis, bacterial meningitis, ventriculitis, bacterial brain abscess, subdural empyema, epidural abscess, neurobrucellosis, neurocysticercosis, and CNS tuberculosis that can aid clinicians with the differential diagnosis, source of infection (e.g., otitis, sinusitis), assessing complications of meningitis (e.g., hydrocephalus, venous sinus thrombosis, strokes), need for neurosurgical interventions and to monitor for the response of therapy. Novel imaging techniques such as fast imaging employing steady-state acquisition (FIESTA), susceptibility-weighted imaging (SWI), and chemical exchange saturation transfer (CEST) contrast are briefly discussed. SUMMARY: Though the radiological findings in CNS infections are vast, certain patterns along with clinical clues from history and examination often pave the way to early diagnosis. This review reiterates the importance of obtaining cranial imaging when necessary, and the various radiological presentations of commonly encountered CNS infections.

Case Report: Isolated Central Nervous System Melioidosis from a Non-Endemic Area.

Central nervous system (CNS) melioidosis is a rare neurological infectious disease which carries a high mortality. We describe a previously healthy middle-aged female, who presented to us with left-sided hemiparesis and was on antitubercular therapy from a previous presumed diagnosis of CNS tuberculoma. Non-characteristic imaging picture, multiple negative body fluid cultures, and positive Cerebrospinal fluid galactomannan led to a further delay in diagnosis. Gram stain of the tissue obtained from brain biopsy revealed Gram-negative rods in "safety pin" appearance. By picking up the colonies that appeared on blood agar and MacConkey agar, the identification of the clinical isolates was performed using VITEK® matrix (BioMérieux, Marcy-L'Etoile, France)-assisted laser desorption ionization time-of-flight mass spectrometry (VITEK MALDI TOF MS database version 3.2) which revealed Burkholderia pseudomallei. After the institution of appropriate treatment, she survived but with significant morbidity. A high index of suspicion should be kept for such previously healthy individuals belonging to non-endemic areas, where presentation is suspicious of an infective etiology, but not improving despite appropriate therapy. This may help in early recognition and institution of recommended treatment so that mortality can be avoided.

A Case of Brain Abscess Caused by Actinomyces Cardiffensis and Parvimonas Micra.

Brain abscesses occur in 0.3-1.3 per 100,000 worldwide each year with 0.4-0.9 in Japan alone. Most of the causes are direct infection from a nearby infectious lesion and are rarely caused by an odontogenic infection. Here, we reported a case of brain abscess suspected to be associated with odontogenic infection. The patient was a 55-year-old woman. Blurred eyes and pain in the left eye noted, for which she consulted an ophthalmologist, but her eyes were normal. She was conscious and was able to converse clearly, but she could not read the letters and had difficulty in writing at the time of admission. A brain abscess was diagnosed based on the head magnetic resonance imaging (MRI) and clinical course, and a small craniotomy abscess drainage was performed. A. cardiffensis and P. micra were detected in the abscess, suggesting the involvement of periodontal disease bacteria. After the surgery, antimicrobial treatment was performed for about 2 months. At the same time, perioperative treatment was performed. On the 70th day after the surgery, tooth extraction, which was considered as the source of infection, was performed. The patient was discharged 74 days after surgery. A good turning point was obtained without relapse of symptoms.

Amide Proton Transfer-Weighted (APTw) Imaging of Intracranial Infection in Children: Initial Experience and Comparison with Gadolinium-Enhanced T1-Weighted Imaging.

PURPOSE: To evaluate the performance of amide proton transfer-weighted (APTw) imaging against the reference standard of gadolinium-enhanced T1-weighted imaging (Gd-T1w) in children with intracranial infection. MATERIALS AND METHODS: Twenty-eight pediatric patients (15 males and 13 females; age range 1-163 months) with intracranial infection were recruited in this study. 2D APTw imaging and conventional MR sequences were conducted using a 3 T MRI scanner. Kappa (κ) statistics and the McNemar test were performed to determine whether the hyperintensity on APTw was related to the enhancement on Gd-T1w. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of APTw imaging to predict lesion enhancement were calculated. RESULT: In twelve patients with brain abscesses, the enhancing rim of the abscesses on the Gd-T1w images was consistently hyperintense on the APTw images. In eight patients with viral encephalitis, three showed slight spotted gadolinium enhancement, while the APTw image also showed a slight spotted high signal. Five of these patients showed no enhancement on Gd-T1w and isointensity on the APTw image. In eleven patients with meningitis, increased APTw signal intensities were clearly visible in gadolinium-enhancing meninges. Sixty infectious lesions (71%) showed enhancement on Gd-T1w images. The sensitivity and specificity of APTw were 93.3% (56/60) and 91.7% (22/24). APTw demonstrated excellent agreement (κ = 0.83) with Gd-T1w, with no significant difference (P = 0.69) in detection of infectious lesions. CONCLUSIONS: These initial data show that APTw MRI is a noninvasive technique for the detection and characterization of intracranial infectious lesions. APTw MRI enabled similar detection of infectious lesions to Gd-T1w and may provide an injection-free means of evaluation of intracranial infection.

Neuroimaging of Emergent and Reemergent Infections.

Infectious diseases emerge and reemerge over the years, and many of them can cause neurologic disease. Several factors contribute to the emergence and reemergence of these conditions, including human population growth, an increase in international travel, the geographic expansion of recognized pathogens to areas where they were previously nonendemic, and greater contact with wild animal reservoirs. The antivaccination social movement has played an important role in the reemergence of infectious diseases, especially some viral conditions. The authors review different viral (arboviruses such as dengue, chikungunya, and Zika virus; enterovirus 71; measles; and influenza), bacterial (syphilis, Lyme disease, and listeriosis), and parasitic (Chagas disease) diseases, focusing primarily on their neurologic complications. Although there are several additional infectious diseases with central nervous system manifestations that could be classified as emergent or reemergent, those listed here are the most relevant from an epidemiologic standpoint and are representative of important public health issues on all continents. The infections caused by these pathogens often show a variety of neuroimaging patterns that can be identified at CT and MRI, and radiology is central to the diagnosis and follow-up of such conditions. Given the increasing relevance of emerging and reemerging infections in clinical practice and public health scenarios, radiologists should be familiar with these infections. Online supplemental material is available for this article. ©RSNA, 2019.

Infectious Myelitis.

Myelitis refers to inflammation of the spinal cord which can result in a spectrum of neurologic impairment. Infectious pathogens are an important etiologic category, and can result in myelitis through direct pathogenic effect or through immune-mediated parainfection; this review focuses on the former category. The spectrum of clinical manifestations is summarized and a diagnostic workup provided to aid clinicians in developing an approach to patients presenting with symptoms suggestive of infectious myelitis. This is followed by an overview of the important viral, bacterial, parasitic, and fungal causes of infectious myelitis. The typical presentations, diagnostic modalities, and treatment approaches are outlined for key pathogens culprit in infectious myelitis to allow clinicians to promptly recognize and diagnose specific infectious etiologies of myelitis.

Clinical Utility of Diffusion-Weighted Imaging in Spinal Infections.

PURPOSE: Both laboratory markers and radiographic findings in the setting of spinal infections can be nonspecific in determining the presence or absence of active infection, and can lag behind both clinical symptoms and antibiotic response. Magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI) has been shown to be helpful in evaluating brain abscesses but has not been commonly used in evaluating spinal infections. We aimed to correlate findings on DWI of the spine to results of microbiological sampling in patients with suspected spinal infections. METHODS: Patients who underwent MRI with DWI for suspicion of spinal infections and microbiological sampling from 2002 to 2010 were identified and reviewed retrospectively in this institutional review board approved study. In addition to DWI, scans included sagittal and axial T1, fast-spin echo (FSE) T2, and post-gadolinium T1 with fat saturation. Regions of interest were drawn on apparent diffusion coefficient (ADC) maps in the area of suspected infections, and ADC values were correlated with microbiological sampling. RESULTS: Of 38 patients with suspected spinal infections, 29 (76%) had positive microbiological sampling, and 9 (24%) had negative results. The median ADC value was 740â€¯× 10-6 mm2/s for patients with positive microbiological sampling and 1980â€¯× 10-6 mm2/s for patients with negative microbiological sampling (p < 0.001). Using an ADC value of 1250â€¯× 10-6 mm2/s or less as the cut-off value for a positive result for spinal infection, sensitivity was 66%, specificity was 88%, positive predictive value was 95%, negative predictive value was 41% and accuracy was 70%. CONCLUSION: In patients with suspected spine infection, ADC values on DWI are significantly reduced in those patients with positive microbiological sampling compared to patients with negative microbiological sampling. The DWI of the spine correlates well with the presence or absence of spinal infection and may complement conventional magnetic resonance imaging (MRI).

The imaging features of cerebral septic infarction in two patients with infective endocarditis.

BACKGROUND: Neurologic complications are frequently seen in infective endocarditis (IE) and were identified in about 70% of patients with IE. However, the imaging features of the cerebral septic infarction were less investigated. PURPOSE: To demonstrate the imaging features of the cerebral septic infarction of IE. MATERIAL AND METHODS: Two patients were clinically diagnosed as IE according to the modified Duke criterion. We studied their imaging profiles and reviewed the literature of the imaging features of neurologic complications of IE. RESULTS: The critical features are multiple ischemic and hemorrhagic lesions, most of which locate at the cortical-medullary junction. The septic infarctions are irregular patchy in shape and have characteristic imaging features indicating complications of IE. CONCLUSION: Magnetic resonance imaging (MRI) with different sequences can detect the features and provide clinical evidence to physicians to make the correct diagnoses and then the treatment plans.

Nocardial spinal epidural abscess with lumbar disc herniation: A case report and review of literature.

RATIONALE: Nocardial spinal epidural abscess is rare. The diagnosis is often difficult to make and, if delayed, poses a high risk of long-term disability. Nocardial spinal epidural abscess with severe lumbar disc herniation has not previously been reported. PATIENT CONCERNS: A 50-year-old man presented with progressive lumbago and leg pain for 6 weeks after receiving acupuncture therapy, and then the patient suddenly occurred urine retention after walking. DIAGNOSES: Clinical examination revealed sign of cauda equina syndrome. Magnetic resonance imaging (MRI) revealed a Lumbar(L)4 to L5 disc herniation, L3 to Sacrum(S)1 epidural abscess, and L2 to S1 paravertebral abscess. The causative organism was Nocardia farcinica. INTERVENTIONS: An urgent paravertebral abscess debridement and right L4 to L5 laminectomy were performed. Simultaneously, the disc tissue protruding into the spinal canal was removed, as well as irrigation and drainage. And antimicrobial treatment was continued for 12 months. OUTCOMES: Fortunately, the patient was able to walk with a cane and urinate autonomously without a catheter, although this remained difficult 7 days after surgery. After 1 year of treatment, the patient has recovered completely and returned to work. LESSONS: Nocardial spinal epidural abscess with severe lumbar disc herniation is extremely rare. Pain from spinal degenerative diseases often masks the early symptoms of spinal infection. It's worth noting that invasive treatment of spine is a way of causing spinal nocardial infection.

Brain Abscess of Basal Ganglia Presenting with Persistent Hiccups.

BACKGROUND: Brain abscesses are well-known to neurologic surgeons with well-recognized presentations, which include seizures, neurologic deficit, and headache. Rare symptoms may lead to a delay in diagnosis, which can be life threatening in the setting of a brain abscess. CASE DESCRIPTION: We present the case of a 46-year-old male with intractable hiccups found to have an abscess of the right basal ganglia. The brain abscess was treated by frameless stereotactic-guided aspiration. The patient's hiccups improved after surgical aspiration and medical management. CONCLUSIONS: A comprehensive literature review confirmed brain abscess as a rare cause of intractable hiccups. In addition, there are few reports of lesions of the basal ganglia causing intractable hiccups. Aspiration and medical therapy resulted in resolution of the hiccups. Knowledge of the hiccup reflex arc and unusual presentation of basal ganglia lesions may shorten time to diagnosis.

Actinomicosis diseminada con compromiso de sistema nervioso central / Disseminated actinomycosis with central nervous system involvement

Resumen La actinomicosis diseminada es muy infrecuente, así como la afección del sistema nervioso central (SNC) asociada, con mortalidad de hasta 28%. Sus manifestaciones pueden ser similares a cuadros infecciosos de otras etiologías, por lo que el conocimiento de la entidad aumenta la sospecha clínica y permite brindar un tratamiento oportuno. Se presenta el caso clínico de un adulto con edema en una extremidad superior como manifestación de una tromboflebitis y una lesión abscedada axilar, en que se confirmó una infección por actinomicetos. Presentó una diseminación hematógena con compromiso de SNC, de evolución fatal.

Actinomycosis is very rare, as well as the central nervous system (CNS) condition associated with it, presenting a mortality up to 28%. Its manifestations could be similar to infectious conditions from other etiologies, thus, having a better understanding of the entity increases clinical suspicion and also it can provide a timely treatment. The clinical case of an adult with edema in an upper extremity is presented as a manifestation of thrombophlebitis and an abscessed axillary lesion, in which actinomycetes infection was confirmed. He presented a haematogenous spread with CNS involvement, with fatal ending.

[Disseminated actinomycosis with central nervous system involvement]. / Actinomicosis diseminada con compromiso de sistema nervioso central.

Actinomycosis is very rare, as well as the central nervous system (CNS) condition associated with it, presenting a mortality up to 28%. Its manifestations could be similar to infectious conditions from other etiologies, thus, having a better understanding of the entity increases clinical suspicion and also it can provide a timely treatment. The clinical case of an adult with edema in an upper extremity is presented as a manifestation of thrombophlebitis and an abscessed axillary lesion, in which actinomycetes infection was confirmed. He presented a haematogenous spread with CNS involvement, with fatal ending.

Rapid Time to Positivity of Cerebrospinal Fluid Culture with Coagulase-Negative Staphylococcus Is More Likely to Reflect a True Infection Than Contamination.

OBJECTIVE: Cerebrospinal fluid (CSF) culture is the gold standard for diagnosing postoperative central nervous system infection. The time to positivity (TTP) of an automated continuous blood culture system may indicate the original concentration of the organism. Coagulase-negative Staphylococcus (CoNS), the common organism recovered in CSF, poses difficulty in differentiating infection from contamination. This study investigated the TTP of CSF culture with CoNS and its relationship to clinical parameters and prognosis. METHODS: Adult neurosurgical patients with CoNS who recovered via the use of CSF culture in BacT/ALERT Pediatric FAN blood culture bottles and were admitted from September 2013 to July 2015 were enrolled. The demographics, clinical and microbiological data, and treatment were reviewed, and the TTP of each culture was retrieved. RESULTS: Thirty-nine adult patients with CoNS recovered from CSF culture were included. The TTP ranged from 7.68 to 57.36 hours. A univariate logistic regression analysis indicated patients with rapid TTP (<21.5 hours) compared with those with longer TTP were more likely to be female, show an effective response to antibiotic therapy within 7 days, have clean-contaminated surgical incisions, and show CSF leak. A multivariate logistic regression analysis indicated that being female, an effective antibiotic therapy within 7 days, and clean-contaminated surgical incisions were independent predictors of rapid TTP. CONCLUSIONS: Targeted antibiotic therapy was more likely to be beneficial to patients with a rapid TTP within 7 days, which suggested that CoNS with a rapid TTP represents the pathogen of central nervous system infection rather than contamination in neurosurgical patients.

Epidemiological and clinical characteristics of neurobrucellosis case patients in Tunisia.

OBJECTIVE: We aimed to identify epidemiological, clinical, therapeutic, diagnostic, and outcome characteristics of neurobrucellosis case patients in Tunisia. PATIENTS AND METHODS: We conducted a retrospective and descriptive study over a 17-year period (January 1997-December 2013). We included all neurobrucellosis patients hospitalized in the infectious disease department of La Rabta Hospital of Tunis during the study period. RESULTS: A total of 13 patients were included in the study: 9 men and 4 women. Mean age was 31.6 years. Six patients presented with meningitis, three with encephalitis, two with meningoencephalitis, and two with meningo-myeloradiculitis. All patients had a lumbar puncture performed. Eleven patients had an abnormal cerebrospinal fluid (CSF) (84.6%): lymphocytic pleocytosis in seven patients, high level of CSF proteins in 11, and low level of CSF glucose in seven. All patients had a positive Brucella serological test in blood. A Brucella serological test was also performed in CSF and was positive for 10 patients (77%). A total of nine patients had a cerebral CT scan and/or MRI performed and abnormalities were observed in six patients. Antibiotic therapy was prescribed to all patients: a combination of rifampicin and co-trimoxazole (n=9) or doxycycline (n=4) for an average duration of eight months. Two patients also received steroids. A positive outcome was observed in 10 patients. Three patients were lost to follow up. CONCLUSION: Brucellosis may be severe when neurological involvement occurs. Brucellosis should be considered in the event of any neurological involvement associated with suggestive epidemiological features.

Central Nervous System Melioidosis Mimics Malignancy: A Case Report and Literature Review.

BACKGROUND: Central nervous system (CNS) melioidosis is notorious because of the difficulty in bacteria eradication and the destruction of brain structures. Early manifestation of CNS melioidosis mimics malignancy or stroke. We present a case of CNS melioidosis that initially manifested as malignancy. CASE DESCRIPTION: A 30-year-old man presented with sudden onset of left limb weakness and seizure. Computed tomography of the brain showed a low-density lesion over the right parietal lobe, and magnetic resonance imaging showed a well-enhanced lobulated lesion. Neuronavigation-guided open surgery was performed but failed to find a malignancy. The patient presented 3 days later with sudden loss of consciousness, pupil dilation, and high fever. Emergent craniectomy was performed for severe right hemisphere swelling with midline shift. After craniectomy, pus was found in the previous operative field. Burkholderia pseudomallei was cultured from pus and blood samples 1 week after collection. The brain lesion developed into an organized abscess and led to mass effect and ventriculitis. Extraventricular drainage and débridement was performed repeatedly accompanied by systemic and intraventricular antibiotic administration. After 4 months of treatment, the patient achieved a complete consciousness recover while left hemiparesis. CONCLUSIONS: CNS melioidosis requires accurate pathogen identification and appropriate long-term antibiotic treatment for eradication of bacteria and prevention of relapse. Débridement and adequate drainage provide better infection control and outcome.

Linezolid and dexamethasone experience in a serious case of listeria rhombencephalitis.

Listeria rhombencephalitis is a rare cause of brain stem encephalitis. We report a case with a history of immunosupressive therapy due to Takayasu's arteritis that was treated with corticosteroids and linezolid for Listeria rhombencephalitis. A 63-year-old woman was admitted to the hospital with fever, headache, nausea, and vomiting. The patient's body temperature was 38°C, and she had a stiff neck. Listeria monocytogenes was isolated from the cerebrospinal fluid (CSF), and penicillin G and gentamicin treatment was initiated. Linezolid and dexamethasone were added. Due to hematuria and thrombocytopenia, the linezolid was discontinued. In immunocompromised patients with CNS infections, Listeria rhombencephalitis should be suspected. Linezolid can be used in combination with dexamethasone.