Central nervous system infections after solid organ transplantation.

PURPOSE OF REVIEW: Significant advances to our understanding of several neuroinfectious complications after a solid organ transplant (SOT) have occurred in the last few years. Here, we review the central nervous system (CNS) infections that are relevant to SOT via a syndromic approach with a particular emphasis on recent updates in the field. RECENT FINDINGS: A few key studies have advanced our understanding of the epidemiology and clinical characteristics of several CNS infections in SOT recipients. Risk factors for poor prognosis and protective effects of standard posttransplant prophylactic strategies have been better elucidated. Newer diagnostic modalities which have broad clinical applications like metagenomic next-generation sequencing, as well as those that help us better understand esoteric concepts of disease pathogenesis have been studied. Finally, several studies have provided newer insights into the treatment of these diseases. SUMMARY: Recent findings reflect the steady progress in our understanding of CNS infections post SOT. They provide several avenues for improvement in the prevention, early recognition, and therapeutic outcomes of these diseases.

Central Nervous System Histoplasma-Associated Post-infectious Inflammatory Response Syndrome (Histo-PIIRS).

We present a case of central nervous system (CNS) histoplasmosis in a previously healthy adult with hepatitis C (HCV) presenting with neurological symptoms refractory to antifungal therapy and ventriculoperitoneal (VP) shunting 4 months after initial diagnosis. Persistent symptoms were thought to be inflammatory rather than infectious given negative cerebrospinal fluid (CSF) and serum fungal antigens. The patient promptly improved after initiation of corticosteroid therapy. Elevated CSF cytokines and regional enhancement on brain MRI resolved with corticosteroid treatment. This is the first case of Histoplasma-associated post-infectious inflammatory response syndrome (Histo-PIIRS) documented by CSF cytokine reduction in response to corticosteroid therapy.

Angio-invasive Cerebral Aspergillosis Resulting in Hemispheric Infarct in an Immunocompetent Man.

BACKGROUND: Cerebral aspergillosis usually affects immunocompromised hosts and may rarely occur in immunocompetent individuals. Due to its angio-invasive nature, Aspergillus may cause various vascular complications, particularly mycotic aneurysms and infarcts. CASE PRESENTATION: A 22-year-old immunocompetent male with diagnosed case of sino-cerebral aspergillosis was taking voriconazole for two months. His headache worsened and repeat imaging showed an increase in the size of the lesion. The patient was managed with right frontal craniotomy and surgical debridement, and voriconazole was continued. After ten days of uneventful post-operative course, the patient developed left-sided hemispheric infarct. The patient is doing well at nine months' follow-up, and he is off voriconazole for three months after the follow-up imaging showed complete resolution of disease. CONCLUSION: Treatment of choice for cerebral aspergillosis is voriconazole. Surgical debridement may be a useful adjunct in patients not responding to voriconazole alone.

Invasive rhino-orbital-cerebral aspergillosis in an immunocompetent patient.

INTRODUCTION: Rhino-orbital-aspergillosis (ROA) is a rare but serious disease in immunocompetent patients. Diagnosis is often delayed due to the absence of specific clinical symptoms. We describe the case of a patient who presented initially with ROA which spread progressively to the right ethmoid-sphenoid sinuses and then to the brain. OBSERVATION: A 61-year-old patient with a history of well-controlled diabetes presented with a sudden severe decrease in right visual acuity. Cerebral MRI showed the presence of an infiltrate in the right orbital apex extending to the homolateral cavernous sinus without any cerebral involvement. A diagnosis of right orbital myositis was made and corticosteroid therapy was started. His symptoms worsened progressively leading to quasi-blindness. A new MRI showed the development of right sphenoid-ethmoid osteolytic lesions. A fungal aetiology was suspected and tests for fungal biomarkers found a ß-(1-3)-D-glucan level of 99pg/ml but negative galactomannan. An ethmoid biopsy was performed for histological and mycological investigations, including the detection of Aspergillus DNA by qPCR. qPCR was positive and culture resulted in the isolation of multi-sensitive Aspergillus fumigatus. Treatment was initiated with voriconazole. Due to persistence of blindness and the appearance of a lesion extending to the right frontal lobe, surgical excision was performed followed by antifungal treatment for a total duration of 1year. The patient is currently stable, but has persistence of blindness in the right eye. CONCLUSION: Invasive ROA is a rare but serious disease in immunocompetent patients which should be evoked in the differential diagnosis of a tumour or vasculitis. Early diagnosis is essential for optimal management.

Acute Fluctuant Neurological Symptoms in Stable Chronic Cryptococcus gattii Cryptococcomas: A Novel Disease Complication.

BACKGROUND: Cryptococcus, a yeast-like fungus, is the most common cause of fungal meningitis worldwide. The Cryptococcus gattii variety is concentrated in Australia has a greater propensity to infect immunocompetent hosts, cause meningitis and form crytococcomas. This case presents a novel disease complication, that is, acute neurological symptoms without seizures, disease progression or reactivation. CASE PRESENTATION: A 58-year-old immunocompetent male was brought to the emergency department with dysarthria and right arm paraesthesias. Computed tomography of the brain brain and magnetic resonance imaging revealed no stroke but found several previously identified crytococcomas that demonstrated no interval change. Blood tests and lumbar puncture found only a low cryptococcal antigen complex titer (CRAG) (1:10) and a negative cell culture. He had remained compliant on his maintenance fluconazole therapy and had no immunocompromise or seizure activity. He was initially treated as a relapse of cryptococcal disease and restarted on induction therapy but after the cell culture returned negative and the symptoms resolved over the following days he was reverted back to maintenance therapy. DISCUSSION AND CONCLUSIONS: Central nervous system cryptococcomas are difficult to treat, chronic infections, that in our patient had lasted over 10 years despite treatment compliance. A true cryptococcal meningitis relapse is indicated by positive cell cultures in previously sterile fluid but cryptococcoma progression is measured by serial magnetic resonance imaging or computed tomography scans. In the case of progression or relapse induction and consolidation therapy should be restarted. Our patient demonstrated neither relapse nor progression but presented with a novel disease complication of acute fluctuating neurology in chronic stable cryptococcomas.

Cryptococcal meningoencephalitis presenting as cerebral venous thrombosis.

Cerebral venous thrombosis (CVT) is characterized by its variety of neurological manifestations and difficulty in diagnosis. In subacute cases, the main symptoms are secondary to increased intracranial pressure. This condition is associated with an extensive range of medical disorders, but only 2% are caused by a CNS infection in recent series. We report a 45-year-old patient, with no previous medical history, who developed a syndrome of increased intracranial pressure as the presentation of a cryptococcal meningoencephalitis (CM) complicated with a CVT. The patient was first diagnosed of a CVT, and later on, the VIH infection and the CM diagnosis were made. Despite being treated with anticoagulation, liposomal amphotericin B, and a therapeutic lumbar puncture, the patient continued to deteriorate and suffered a respiratory arrest secondary to the increased intracranial pressure, with subsequent brain death. Cryptococcus is an infrequent cause of CNS infection in developed countries, despite being the most frequent cause of meningits in adults in several countries with high rates of HIV infection. CVT is a very rare complication of CM which can contribute to worsen the increased intracranial pressure and in consequence, its prognosis and outcome. A high level of suspicion is needed for diagnosing CM as the underlying cause of CVT and the subsequent increased intracranial pressure should be managed exhaustively.

Intracranial invasive mycosis mimicking hepatic encephalopathy in a patient with cirrhosis.

A 45-year-old man with alcohol-related decompensated cirrhosis presented with jaundice, fever, headache and altered sensorium. At presentation, he had tachycardia, disorientation to time and place, asterixis, icterus and upgoing plantar response. Investigations showed anaemia, thrombocytopenia, leucocytosis, hyperbilirubinemia and elevated arterial ammonia. Despite management with antihepatic coma measures and normalisation of ammonia, broad-spectrum antibiotics, 20% albumin, the patient worsened. On day 3, the patient developed generalised tonic-clonic seizure prompting mechanical ventilation. Examination showed right proptosis, chemosis and pupillary anisocoria. MRI brain showed multifocal infarcts in the right temporal lobe, right cerebellum and brainstem with inflammation in the right orbit, infratemporal fossa with right internal carotid artery thrombosis, and suspicious maxillary sinus thickening. Nasal scrapings showed aseptate fungal hyphae and serum galactomannan index was positive. Despite receiving liposomal amphotericin-B, patient had an unfavourable outcome. Intracranial invasive mycosis can mimic hepatic encephalopathy and is associated with high mortality in cirrhotics. A high index of suspicion, positive biomarkers and diagnostic radiology may provide the key to the diagnosis.

[Neurohistoplasmosis and cutaneous leishmaniasis in an immunocompetent patient]. / Neurohistoplasmosis y leishmaniasis cutánea en paciente inmunocompetente.

Histoplasmosis and leishmaniasis are neglected and endemic diseases in Argentina, and generally are found associated with immunosuppression. We report the case of an immunocompetent 16-years-old man with simultaneous occurrence of central nervous system histoplasmosis and cutaneous leishmaniasis. Upon admission, the patient showed a one-month old skin lesion in a leg and mild paraparesis. Imaging studies detected thickening and edema in the spinal cord and the cerebrospinal fluid analysis was within normal range. The case was diagnosed as a demyelinating disorder and treated with high-dose short-term steroids. Seventy-two hours later the patient showed severe paraparesis and nuclear magnetic resonance imaging revealed nodular lesions in the spinal cord. Histoplasma capsulatum belonging to the phylogenetic species LamB was isolated from cerebrospinal fluid samples. The patient received intravenous antifungal therapy with amphotericin B for 30 days, followed by oral fluconazole and itraconazole for one year. Three months after initiation of antifungal treatment, the cutaneous lesion recrudesced and Leishmania amastigotes were observed on microscopic examination. The cutaneous leishmaniasis was treated with intramuscular meglumine antimoniate. The patient's outcome was favorable after treatment for both diseases.

La histoplasmosis y la leishmaniasis son enfermedades olvidadas, endémicas en Argentina, y generalmente se asocian a inmunocompromiso. Presentamos el caso de un varón de 16 años, inmunocompetente, con histoplasmosis del sistema nervioso central y leishmaniasis cutánea. Inicialmente, el paciente presentó una lesión en la pierna de un mes de evolución seguida de paraparesia leve, diagnosticada como un proceso de desmielinización mediante estudios de imágenes. El cuadro fue tratado con altas dosis de corticoides y en 72 horas evolucionó a paraparesia grave con lesiones nodulares en las vértebras cervicales, observadas en las imágenes de resonancia magnética nuclear. Se aisló Histoplasma capsulatum de líquido cefalorraquídeo, genotípicamente identificado como perteneciente a la especie filogenética LamB. El paciente recibió tratamiento intravenoso con anfotericina B deoxicolato durante 30 días y posteriormente fluconazol e itraconazol oral durante un año. A los tres meses de iniciado el tratamiento con antifúngicos se reactivó la lesión de la pierna y en el examen directo se observaron amastigotes de Leishmania. La leishmaniasis cutánea fue tratada con antimoniato de meglumina intramuscular. La respuesta clínica al tratamiento de ambas enfermedades fue favorable.

Neurohistoplasmosis y leishmaniasis cutánea en paciente inmunocompetente / Neurohistoplasmosis and cutaneous leishmaniasis in an immunocompetent patient

La histoplasmosis y la leishmaniasis son enfermedades olvidadas, endémicas en Argentina, y generalmente se asocian a inmunocompromiso. Presentamos el caso de un varón de 16 años, inmunocompetente, con histoplasmosis del sistema nervioso central y leishmaniasis cutánea. Inicialmente, el paciente presentó una lesión en la pierna de un mes de evolución seguida de paraparesia leve, diagnosticada como un proceso de desmielinización mediante estudios de imágenes. El cuadro fue tratado con altas dosis de corticoides y en 72 horas evolucionó a paraparesia grave con lesiones nodulares en las vértebras cervicales, observadas en las imágenes de resonancia magnética nuclear. Se aisló Histoplasma capsulatum de líquido cefalorraquídeo, genotípicamente identificado como perteneciente a la especie filogenética LamB. El paciente recibió tratamiento intravenoso con anfotericina B deoxicolato durante 30 días y posteriormente fluconazol e itraconazol oral durante un año. A los tres meses de iniciado el tratamiento con antifúngicos se reactivó la lesión de la pierna y en el examen directo se observaron amastigotes de Leishmania. La leishmaniasis cutánea fue tratada con antimoniato de meglumina intramuscular. La respuesta clínica al tratamiento de ambas enfermedades fue favorable.

Histoplasmosis and leishmaniasis are neglected and endemic diseases in Argentina, and generally are found associated with immunosuppression. We report the case of an immunocompetent 16-years-old man with simultaneous occurrence of central nervous system histoplasmosis and cutaneous leishmaniasis. Upon admission, the patient showed a one-month old skin lesion in a leg and mild paraparesis. Imaging studies detected thickening and edema in the spinal cord and the cerebrospinal fluid analysis was within normal range. The case was diagnosed as a demyelinating disorder and treated with high-dose short-term steroids. Seventy-two hours later the patient showed severe paraparesis and nuclear magnetic resonance imaging revealed nodular lesions in the spinal cord. Histoplasma capsulatum belonging to the phylogenetic species LamB was isolated from cerebrospinal fluid samples. The patient received intravenous antifungal therapy with amphotericin B for 30 days, followed by oral fluconazole and itraconazole for one year. Three months after initiation of antifungal treatment, the cutaneous lesion recrudesced and Leishmania amastigotes were observed on microscopic examination. The cutaneous leishmaniasis was treated with intramuscular meglumine antimoniate. The patient´s outcome was favorable after treatment for both diseases.

The Frozen Brain State of Cryptococcus gattii: A Globe-Trotting, Tropical, Neurotropic Fungus.

Initially reported in tropical regions, Cryptococcus gattii infection is now diagnosed globally. Methods: case report; Literature review. Although initial reports described outbreaks of pulmonary and central nervous system (CNS) disease in tropical regions such as Australia and New Guinea, it is now clear that Cryptococcus gattii is a global, neurotropic pathogen. In contrast with C. neoformans, C. gattii patients are more likely to present with cryptococcomas in the brain and lungs and are often HIV negative. Imaging findings can mimick cancer leading to delays in diagnosis and definitive treatment. Some experts have speculated that the spread of C. gattii is due to climate change, newly recognized genotypes that cause disease in temperate zones (genotype VGII), international travel, and improved awareness among physicians and veterinarians. We emphasize neurocritical and neurosurgical management, because patients with CNS involvement often have high intracranial pressures (ICP). Cryptococcus gattii patients often have elevated ICP without 'red flag' radiographic signs of elevated ICP such as ventriculomegaly, cerebral edema, or effaced basal cisterns. Therefore, diagnosis of high ICP should be suspected based on clinical symptoms such as incapacitating headaches, progressive visual loss and associated papilledema, and then confirmed by measuring the opening pressure with lumbar puncture (LP). Cerebral intraparenchymal deposition of the large cryptococcal polysaccharide capsule and cryptococcal organisms causes poor brain compliance leading to a 'frozen brain state.' Mortality rates and clinical outcomes are significantly improved with early diagnosis, antifungal therapies, steroids, and aggressive management of elevated ICP including cerebrospinal fluid (CSF) diversion by serial LP's, external ventricular drains and CSF shunts. Following institution of antifungal therapy, about 10% of patients can worsen due to immune reconstitution inflammatory syndrome which responds to steroids. We recommend neurocritical and neurosurgical management of C. gattii patients with CNS involvement and elevated ICP. There is often poor correlation between elevated ICP and neuroimaging due to the frozen brain state.

Central nervous system histoplasmosis: Multicenter retrospective study on clinical features, diagnostic approach and outcome of treatment.

Central nervous system (CNS) involvement occurs in 5 to 10% of individuals with disseminated histoplasmosis. Most experience has been derived from small single center case series, or case report literature reviews. Therefore, a larger study of central nervous system (CNS) histoplasmosis is needed in order to guide the approach to diagnosis, and treatment.A convenience sample of 77 patients with histoplasmosis infection of the CNS was evaluated. Data was collected that focused on recognition of infection, diagnostic techniques, and outcomes of treatment.Twenty nine percent of patients were not immunosuppressed. Histoplasma antigen, or anti-Histoplasma antibodies were detected in the cerebrospinal fluid (CSF) in 75% of patients. One year survival was 75% among patients treated initially with amphotericin B, and was highest with liposomal, or deoxycholate formulations. Mortality was higher in immunocompromised patients, and patients 54 years of age, or older. Six percent of patients relapsed, all of whom had the acquired immunodeficiency syndrome (AIDS), and were poorly adherent with treatment.While CNS histoplasmosis occurred most often in immunocompromised individuals, a significant proportion of patients were previously, healthy. The diagnosis can be established by antigen, and antibody testing of the CSF, and serum, and antigen testing of the urine in most patients. Treatment with liposomal amphotericin B (AMB-L) for at least 1 month; followed by itraconazole for at least 1 year, results in survival among the majority of individuals. Patients should be followed for relapse for at least 1 year, after stopping therapy.

Fungal infection in neural tissue of patients with amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease and the main cause of motor neuron pathology. The etiology of the disease remains unknown, and no effective therapy exists to halt the disease or improve the quality of life. Here, we provide compelling evidence for the existence of fungal infection in ALS. Immunohistochemistry analysis using a battery of antifungal antibodies revealed fungal structures such as yeast and hyphae in the motor cortex, the medulla and the spinal cord, in eleven patients with ALS. Some fungal structures were localized intracellularly and even intranuclearly, indicating that this infection is not the result of post-mortem colonization. By contrast, this burden of fungal infection cannot be observed in several CNS areas of control subjects. PCR analysis and next generation sequencing of DNA extracted from frozen neural tissue identified a variety of fungal genera including Candida, Malassezia, Fusarium, Botrytis, Trichoderma and Cryptococcus. Overall, our present observations provide strong evidence for mixed fungal infections in ALS patients. The exact mixed infection varies from patient to patient consistent with the different evolution and severity of symptoms in each ALS patient. These novel findings provide a logical explanation for the neuropathological observations of this disease, such as neuroinflammation and elevated chitinase levels, and could help to implement appropriate therapies.

Infant Central Nervous System Aspergillosis with First-episode of Intracranial Hemorrhage: A case report.

RATIONALE: Central nervous system (CNS) aspergillosis has the characteristics of multifocality, polymorphism, and coexistence of pathological types, and missed diagnosis and misdiagnosis frequently occur at the initial stage. The thesis reports a rare case of infant infection of CNS aspergillosis with the first-episode of intracranial hemorrhage. PATIENT CONCERNS: An 11-month-old female infant suffered convulsion and coma two days after the onset of fever and emesis. Its cranial computed tomography (CT) displayed subdural hemorrhage in the left tentorium cerebelli and tests indicated normal cerebrospinal fluid (CSF). Three days after being hospitalized, the infant had difficulty breathing and its CT presents consolidation in the right lung. However, treatment with ceftriaxone (ivgtt) had no effect on the baby. DIAGNOSIS: The patient's bronchoalveolar lavage fluid (BALF) was cultured into Aspergillus spp, its galactomannan (GM) antigen in CSF counted 3.0, higher than that in BALF which counted 2.6, and cranial magnetic resonance imaging (MRI) revealed multiple ring reinforced tubercles in sulci. Hence it was clinically diagnosed with CNS aspergillosis. INTERVENTIONS: Voriconazole for intravenous injection. After the intravenous injection, its trough concentration was 4.2 µg/mL, and it was within the recommended range. OUTCOMES: After one week's treatment with voriconazole, the infant's consciousness was improved. Four weeks later, with normothermia and clear consciousness, the patient was discharged. With oral administration of voriconazole up to 16 weeks, its physical state suggests no relapse and cranial MRI indicated disappearance of nodules in sulci. LESSONS: CNS aspergillosis with first-episode of intracranial hemorrhage probably leads to misdiagnosis and GM test combined with cranial MRI can augment its accuracy in the early diagnosis.

Clinical management of infectious cerebral vasculitides.

A wide range of infections (virus, bacteria, parasite and fungi) may cause cerebral vasculitides. Headache, seizures, encephalopathy and stroke are common forms of presentation. Infection and inflammation of intracranial vessels may cause pathological vascular remodelling, vascular occlusion and ischemia. Vasculitis in chronic meningitis may cause ischemic infarctions, and is associated with poor outcome. Appropriate neuroimaging (CT-angiography, MR-angiography, conventional 4-vessel angiography) and laboratory testing (specific antibodies in blood and CSF, CSF culture and microscopy) and even brain biopsy are needed to quickly establish the aetiology. Enhancement of contrast, wall thickening and lumen narrowing are radiological signs pointing to an infectious vasculitis origin. Although corticosteroids and prophylactic antiplatelet therapy have been used in infectious cerebral vasculitis, there are no randomized clinical trials that have evaluated their efficacy and safety. Stable mycotic aneurysms can be treated with specific antimicrobial therapy. Endovascular therapy and intracranial surgery are reserved for ruptured aneurysms or enlarging unruptured aneurysms.