Imaging cerebral malaria with a susceptibility-weighted MR sequence

Neuroimaging of Infectious Vasculopathy

Vasculitis is a complication of several infectious diseases affecting the central nervous system, which may result in ischemic and/or hemorrhagic stroke, transient ischemic attack, and aneurysm formation. Infectious agents may directly infect the endothelium causing vasculitis or indirectly affect the vessel wall through an immunological cascade. Clinical manifestations usually overlap with those of noninfectious vascular diseases, making diagnosis challenging. Neuroimaging enables the identification of inflammatory changes in intracranial vasculitis. In this article, we review the imaging features of infectious vasculitis of bacterial, viral, fungal and parasitic causes.

Pathogenetic mechanisms and treatment targets in cerebral malaria

Malaria, the most prevalent mosquito-borne infectious disease worldwide, has accompanied humanity for millennia and remains an important public health issue despite advances in its prevention and treatment. Most infections are asymptomatic, but a small percentage of individuals with a heavy parasite burden develop severe malaria, a group of clinical syndromes attributable to organ dysfunction. Cerebral malaria is an infrequent but life-threatening complication of severe malaria that presents as an acute cerebrovascular encephalopathy characterized by unarousable coma. Despite effective antiparasite drug treatment, 20% of patients with cerebral malaria die from this disease, and many survivors of cerebral malaria have neurocognitive impairment. Thus, an important unmet clinical need is to rapidly identify people with malaria who are at risk of developing cerebral malaria and to develop preventive, adjunctive and neuroprotective treatments for cerebral malaria. This Review describes important advances in the understanding of cerebral malaria over the past two decades and discusses how these mechanistic insights could be translated into new therapies.

Imaging features of fulminant cerebral malaria: A case report

Cerebral malaria is associated with high mortality and morbidity in patients infected with Plasmodium Falciparum. The mechanisms of cerebral malaria include sequestration of parasitized red blood cells in brain capillaries, production of cytokines, immune cell/platelet accumulation, and release of microparticles, resulting in disruption of the blood-brain barrier, which caused brain injuries. The severity of this reflects on neurological findings ranging from simple delirium to profound coma. We herein present unique magnetic resonance imaging findings of a case of fulminant cerebral malaria as computed tomography studies usually underestimate the extent of cerebral involvement in malaria.

Temporal Trends of Blood Glucose in Children with Cerebral Malaria

Hypoglycemia, defined as a blood glucose < 2.2 mmol/L, is associated with death in pediatric cerebral malaria (CM). The optimal duration of glucose monitoring in CM is unknown. We collected data from 1,674 hospitalized Malawian children with CM to evaluate the association between hypoglycemia and death or neurologic disability in survivors. We assessed the optimal duration of routine periodic measurements of blood glucose. Children with hypoglycemia at admission had a 2.87-fold higher odds (95% CI: 1.35-6.09) of death and, if they survived, a 3.21-fold greater odds (95% CI: 1.51-6.86) of sequelae at hospital discharge. If hypoglycemia was detected at 6 hours but not at admission, there was a 7.27-fold higher odds of death (95% CI: 1.85-8.56). The presence of newly developed hypoglycemia after admission was not independently associated with neurological sequelae in CM survivors. Among all new episodes of blood sugar below a treatment threshold of 3.0 mmol/L, 94.7% occurred within 24 hours of admission. In those with blood sugar below 3.0 mmol/L in the first 24 hours, low blood sugar persisted or recurred for up to 42 hours. Hypoglycemia at admission or 6 hours afterward is strongly associated with mortality in CM. Children with CM should have 24 hours of post-admission blood glucose measurements. If a blood glucose less than the treatment threshold of 3.0 mmol/L is not detected, routine assessments may cease. Children who have blood sugar values below the treatment threshold detected within the first 24 hours should continue to have periodic glucose measurements for 48 hours post-admission.

Cerebral Amyloid Angiopathy

Cerebral amyloid angiopathy (CAA) is associated with deposition of amyloid proteins within the intracranial vessels. It is most frequently sporadic and risk increases with advancing age. Amyloid deposition is associated with increased risk of peripheral microhemorrhage, lobar hemorrhage, and/or repetitive subarachnoid hemorrhage. The presence of a peripherally located lobar hemorrhage on computed tomography in an elderly patient should raise concern for underlying CAA, as should multiple foci of peripheral susceptibility artifact or superficial siderosis on susceptibility-weighted imaging, the most sensitive modality for these findings. Newer PET radiotracers are also useful in detecting amyloid deposition.

Cerebral Malaria Is Regulated by Host-Mediated Changes in Plasmodium Gene Expression

Cerebral malaria (CM), the deadliest complication of Plasmodium infection, is a complex and unpredictable disease. However, our understanding of the host and parasite factors that cause CM is limited. Using a mouse model of CM, experimental CM (ECM), we performed a three-way comparison between ECM-susceptible C57BL/6 mice infected with ECM-causing Plasmodium ANKA parasites [ANKA(C57BL/6)], ECM-resistant BALB/c mice infected with Plasmodium ANKA [ANKA(BALB/c)], and C57BL/6 mice infected with Plasmodium NK65 that does not cause ECM [NK65(C57BL/6)]. All ANKA(C57BL/6) mice developed CM. In contrast, in ANKA(BALB/c) and NK65(C57BL/6), infections do not result in CM and proceed similarly in terms of parasite growth, disease course, and host immune response. However, parasite gene expression in ANKA(BALB/c) was remarkably different than that in ANKA(C57BL/6) but similar to the gene expression in NK65(C57BL/6). Thus, Plasmodium ANKA has an ECM-specific gene expression profile that is activated only in susceptible hosts, providing evidence that the host has a critical influence on the outcome of infection. IMPORTANCE Hundreds of thousands of lives are lost each year due to the brain damage caused by malaria disease. The overwhelming majority of these deaths occur in young children living in sub-Saharan Africa. Thus far, there are no vaccines against this deadly disease, and we still do not know why fatal brain damage occurs in some children while others have milder, self-limiting disease progression. Our research provides an important clue to this problem. Here, we showed that the genetic background of the host has an important role in determining the course and the outcome of the disease. Our research also identified parasite molecules that can potentially be targeted in vaccination and therapy approaches.

Transcellular blood-brain barrier disruption in malaria-induced reversible brain edema

We present how reversible edema can reliably be induced in experimental cerebral malaria and show that it is associated with transcellular blood–brain barrier disruption and delayed microhemorrhages.

Brain swelling occurs in cerebral malaria (CM) and may either reverse or result in fatal outcome. It is currently unknown how brain swelling in CM reverses, as brain swelling at the acute stage is difficult to study in humans and animal models with reliable induction of reversible edema are not known. In this study, we show that reversible brain swelling in experimental murine CM can be induced reliably after single vaccination with radiation-attenuated sporozoites as proven by in vivo high-field magnetic resonance imaging. Our results provide evidence that brain swelling results from transcellular blood–brain barrier disruption (BBBD), as revealed by electron microscopy. This mechanism enables reversal of brain swelling but does not prevent persistent focal brain damage, evidenced by microhemorrhages, in areas of most severe BBBD. In adult CM patients magnetic resonance imaging demonstrate microhemorrhages in more than one third of patients with reversible edema, emphasizing similarities of the experimental model and human disease. Our data suggest that targeting transcellular BBBD may represent a promising adjunct therapeutic approach to reduce edema and may improve neurological outcome.

Infectious Causes of Stroke

Stroke is one of the primary causes of mortality and morbidity worldwide. It can be ischemic or hemorrhagic, and the former can be due to an in-situ thrombus or a distant embolus. Despite being a rare cause, stroke can also be caused in the setting of infection. Bacterial agents are the most common cause of stroke, among other infectious agents. Until the antibiotic era, rheumatic heart disease was a predisposing risk factor of infective endocarditis. VZV is the most common cause of strokes in pediatric and adult populations. Cryptococcus and Candida spp are the most common yeasts involved in CNS infections, especially in immunocompromised patients. In COVID-19 patients, ischemic strokes are more common than hemorrhagic strokes. In this review, we will discuss the most common infectious agents, with particular emphasis on COVID-19.

Nervous System Involvement in Coronavirus Disease 2019: Results from a Retrospective Consecutive Neuroimaging Cohort

Background Neurologic complications in coronavirus disease 2019 (COVID-19) have been described, but the understanding of their pathophysiologic causes and neuroanatomical correlates remains limited. Purpose To report on the frequency and type of neuroradiological findings in COVID-19. Materials and Methods In this retrospective study, all consecutive adult hospitalized patients with polymerase chain reaction positivity for severe acute respiratory syndrome coronavirus 2 and who underwent neuroimaging at Karolinska University Hospital between March 2 and May 24, 2020, were included. All examinations were systematically re-evaluated by 12 readers. Summary descriptive statistics were calculated. Results A total of 185 patients with COVID-19 (62 years ± 14 [standard deviation]; 138 men) underwent neuroimaging. In total, 222 brain CT, 47 brain MRI, and seven spinal MRI examinations were performed. Intra-axial susceptibility abnormalities were the most common finding (29 of 39; 74%, 95% CI: 58, 87) in patients who underwent brain MRI, often with an ovoid shape suggestive of microvascular pathology and with a predilection for the corpus callosum (23 of 39; 59%; 95% CI: 42, 74) and juxtacortical areas (14 of 39; 36%; 95% CI: 21, 53). Ischemic and macrohemorrhagic manifestations were also observed, but vascular imaging did not demonstrate overt abnormalities. Dynamic susceptibility contrast perfusion MRI in 19 patients did not reveal consistent asymmetries between hemispheres or regions. Many patients (18 of 41; 44%; 95% CI: 28, 60) had leukoencephalopathy and one patient had a cytotoxic lesion of the corpus callosum. Other findings included olfactory bulb signal abnormalities (seven of 37; 19%), prominent optic nerve subarachnoid spaces (20 of 36; 56%), and enhancement of the parenchyma (three of 20; 15%), leptomeninges (three of 20; 15%), cranial nerves (two of 20; 10%), and spinal nerves (two of four; 50%). At MRI follow-up, regression of leukoencephalopathy and progressive leptomeningeal enhancement was observed in one patient each, respectively, which is suggestive of dynamic processes. Conclusion Patients with coronavirus disease 2019 had a wide spectrum of vascular and inflammatory involvement of both the central and peripheral nervous system. © RSNA, 2020 Online supplemental material is available for this article.

Brain magnetic resonance imaging in imported malaria

Background

Previous studies have documented a spectrum of brain magnetic resonance imaging (MRI) abnormalities in patients with cerebral malaria, but little is known about the prevalence of such abnormalities in patients with non-cerebral malaria. The aim of this study was to assess the frequency of brain MRI findings in returning travellers with non-cerebral malaria.

Methods

A total of 17 inpatients with microscopically confirmed Plasmodium falciparum non-cerebral malaria underwent structural brain MRI at 3.0 Tesla, including susceptibility-weighted imaging (SWI). Presence of imaging findings was recorded and correlated with clinical findings and parasitaemia.

Results

Structural brain abnormalities included a hyperintense lesion of the splenium on T2-weighted imaging (n = 3) accompanied by visible diffusion restriction (n = 2). Isolated brain microhaemorrhage was detected in 3 patients. T2-hyperintense signal abnormalities of the white matter ranged from absent to diffuse (n = 10 had 0–5 lesions, n = 5 had 5–20 lesions and 2 patients had more than 50 lesions). Imaging findings were not associated with parasitaemia or HRP2 levels.

Conclusion

Brain MRI reveals a considerable frequency of T2-hyperintense splenial lesions in returning travellers with non-cerebral malaria, which appears to be independent of parasitaemia.

Cerebral amyloid angiopathy: Review of clinico-radiological features and mimics

Cerebral amyloid angiopathy (CAA) is an important cause of lobar intracerebral haemorrhage (ICH) in the elderly, but has other clinico-radiological manifestations. In the last two decades, certain magnetic resonance imaging (MRI) sequences, namely gradient-recalled echo imaging and the newer and more sensitive susceptibility-weighted imaging, have been utilised to detect susceptibility-sensitive lesions such as cerebral microbleeds and cortical superficial siderosis. These can be utilised sensitively and specifically by the Modified Boston Criteria to make a diagnosis of CAA without the need for 'gold-standard' histopathology from biopsy. However, recently, other promising MRI biomarkers of CAA have been described which may further increase precision of radiological diagnosis, namely chronic white matter ischaemia, cerebral microinfarcts and lobar lacunes, cortical atrophy, and increased dilated perivascular spaces in the centrum semiovale. However, the radiological manifestations of CAA, as well as their clinical correlates, may have other aetiologies and mimics. It is important for the radiologist to be aware of these clinico-radiological features and mimics to accurately diagnose CAA. This is increasingly important in a patient demographic that has a high prevalence for use of antiplatelet and antithrombotic medications for other comorbidities which inherently carries an increased risk of ICH in patients with CAA.

Plasmodium vivax Malaria Presenting with Multifocal Hemorrhagic Brain Infarcts in a School-going Child

Cerebral malaria is a well-known complication of Plasmodium falciparum malaria. Over recent years, however, Plasmodium vivax also has been reported to cause cerebral malaria with or without co-infection with P. falciparum Here, we report a boy aged 10 years presenting with acute febrile encephalopathy with raised intracranial pressure to the emergency, who was later diagnosed to have P. vivax malaria. His neurological status improved gradually during 6 weeks of pediatric intensive care unit stay. We report this case to highlight the unusual radiologic findings in the patient, such as multifocal hemorrhagic infarcts in the brainstem, bilateral thalami, frontal cortex and basal ganglia, which have not been reported with P. vivax malaria.

Bacterial, Fungal, and Parasitic Infections of the Central Nervous System: Radiologic-Pathologic Correlation and Historical Perspectives

Despite remarkable progress in prevention and treatment, infectious diseases affecting the central nervous system remain an important source of morbidity and mortality, particularly in less-developed countries and in immunocompromised persons. Bacterial, fungal, and parasitic pathogens are derived from living organisms and affect the brain, spinal cord, or meninges. Infections due to these pathogens are associated with a variety of neuroimaging patterns that can be appreciated at magnetic resonance imaging in most cases. Bacterial infections, most often due to Streptococcus, Haemophilus, and Neisseria species, cause significant meningitis, whereas the less common cerebritis and subsequent abscess formation have well-documented progression, with increasingly prominent altered signal intensity and corresponding contrast enhancement. Atypical bacterial infections are characterized by the development of a granulomatous response, classically seen in tuberculosis, in which the tuberculoma is the most common parenchymal form of the disease; spirochetal and rickettsial diseases are less common. Fungal infections predominate in immunocompromised hosts and are caused by yeasts, molds, and dimorphic fungi. Cryptococcal meningitis is the most common fungal infection, whereas candidiasis is the most common nosocomial infection. Mucormycosis and aspergillosis are characterized by angioinvasiveness and are associated with high morbidity and mortality among immunocompromised patients. In terms of potential exposure in the worldwide population, parasitic infections, including neurocysticercosis, toxoplasmosis, echinococcosis, malaria, and schistosomiasis, are the greatest threat. Rare amebic infections are noteworthy for their extreme virulence and high mortality. The objective of this article is to highlight the characteristic neuroimaging manifestations of bacterial, fungal, and parasitic diseases, with emphasis on radiologic-pathologic correlation and historical perspectives.

Magnetic resonance imaging during life: the key to unlock cerebral malaria pathogenesis?

Understanding the mechanisms underlying the pathophysiology of cerebral malaria in patients with Plasmodium falciparum infection is necessary to implement new curative interventions. While autopsy-based studies shed some light on several pathological events that are believed to be crucial in the development of this neurologic syndrome, their investigative potential is limited and has not allowed the identification of causes of death in patients who succumb to it. This can only be achieved by comparing features between patients who die from cerebral malaria and those who survive. In this review, several alternative approaches recently developed to facilitate the comparison of specific parameters between fatal, non-fatal cerebral malaria and uncomplicated malaria patients are described, as well as their limitations. The emergence of neuroimaging as a revolutionary tool in identifying critical structural and functional modifications of the brain during cerebral malaria is discussed and highly promising areas of clinical research using magnetic resonance imaging are highlighted.

Infectious causes of stroke

Most infectious pathogens have anecdotal evidence to support a link with stroke, but certain pathogens have more robust associations, in which causation is probable. Few dedicated prospective studies of stroke in the setting of infection have been done. The use of head imaging, a clinical standard of diagnostic care, to confirm stroke and stroke type is not universal. Data for stroke are scarce in locations where infections are probably most common, making it difficult to reach conclusions on how populations differ in terms of risk of infectious stroke. The treatment of infections and stroke, when concomitant, is based on almost no evidence and requires dedicated efforts to understand variations that might exist. We highlight the present knowledge and emphasise the need for stronger evidence to assist in the diagnosis, treatment, and secondary prevention of stroke in patients in whom an infectious cause for stroke is probable.

Rabies, tetanus, leprosy, and malaria

The developing world is still endemic to rabies, tetanus, leprosy, and malaria. Globally more than 55000 people die of rabies each year, about 95% in Asia and Africa. Annually, more than 10 million people, mostly in Asia, receive postexposure vaccination against the disease. World Health Organization estimated tetanus-related deaths at 163000 in 2004 worldwide. Globally, the annual detection of new cases of leprosy continues to decline and the global case detection declined by 3.54% during 2008 compared to 2007. Malaria is endemic in most countries, except the US, Canada, Europe, and Russia. Malaria accounts for 1.5-2.7 million deaths annually. Much of the disease burden related to these four infections is preventable.

Imaging Plasmodium immunobiology in the liver, brain, and lung

Plasmodium falciparum malaria is responsible for the deaths of over half a million African children annually. Until a decade ago, dynamic analysis of the malaria parasite was limited to in vitro systems with the typical limitations associated with 2D monocultures or entirely artificial surfaces. Due to extremely low parasite densities, the liver was considered a black box in terms of Plasmodium sporozoite invasion, liver stage development, and merozoite release into the blood. Further, nothing was known about the behavior of blood stage parasites in organs such as the brain where clinical signs manifest and the ensuing immune response of the host that may ultimately result in a fatal outcome. The advent of fluorescent parasites, advances in imaging technology, and availability of an ever-increasing number of cellular and molecular probes have helped illuminate many steps along the pathogenetic cascade of this deadly tropical parasite.

Adjunctive management of malaria

PURPOSE OF REVIEW

Artesunate treatment reduces mortality in severe malaria when compared with quinine. Nevertheless, severe malaria is associated with mortality rates between 1.4 and 9.5% after hospitalization. This review puts into context the recent developments in understanding the pathophysiology of malaria and how these may be reflected in renewed attempts at improving adjunct therapies. Identifying new adjunct approaches has been particularly difficult for severe malaria because most interventions have either caused harm or failed to confer benefit.

RECENT FINDINGS

Imaging and postmortem findings in children with severe and cerebral malaria have given impetus to study new interventions that could be added to antimalarial treatment. Some pilot studies have (re)tested different approaches to improve complications of cerebral malaria such as the use of N-acetyl cysteine or mannitol. Fluids administration, blood transfusions and red cell exchanges in severe malaria are controversial and important areas that are also reviewed with new evidence. Other interventions such as measures to increase nitric oxide, manage acute renal failure or optimize artesunate dosing are discussed.

SUMMARY

Outcomes with adjunct therapies for severe malaria have been poor, but as insights into pathophysiological processes are deepened it may be possible eventually to reduce mortality further.

Acute brain MRI findings in 120 Malawian children with cerebral malaria: new insights into an ancient disease

BACKGROUND AND PURPOSE

There have been few neuroimaging studies of pediatric CM, a common often fatal tropical condition. We undertook a prospective study of pediatric CM to better characterize the MRI features of this syndrome, comparing findings in children meeting a stringent definition of CM with those in a control group who were infected with malaria but who were likely to have a nonmalarial cause of coma.

MATERIALS AND METHODS

Consecutive children admitted with traditionally defined CM (parasitemia, coma, and no other coma etiology evident) were eligible for this study. The presence or absence of malaria retinopathy was determined. MRI findings in children with ret+ CM (patients) were compared with those with ret- CM (controls). Two radiologists blinded to retinopathy status jointly developed a scoring procedure for image interpretation and provided independent reviews. MRI findings were compared between patients with and without retinopathy, to assess the specificity of changes for patients with very strictly defined CM.

RESULTS

Of 152 children with clinically defined CM, 120 were ret+, and 32 were ret-. Abnormalities much more common in the patients with ret+ CM were markedly increased brain volume; abnormal T2 signal intensity; and DWI abnormalities in the cortical, deep gray, and white matter structures. Focal abnormalities rarely respected arterial vascular distributions. Most of the findings in the more clinically heterogeneous ret- group were normal, and none of the abnormalities noted were more prevalent in controls.

CONCLUSIONS

Distinctive MRI findings present in patients meeting a stringent definition of CM may offer insights into disease pathogenesis and treatment.

Neuroimaging of pediatric intracranial infection--part 2: TORCH, viral, fungal, and parasitic infections

In the second half of this 2-part review, the neuroimaging features of the most common viral, fungal, and parasitic infections of the pediatric central nervous system are discussed. Brief discussions of epidemiology and pathophysiology will be followed by a review of the imaging findings and potential differential considerations.

Relevance of neuroimaging in the diagnosis and management of tropical neurologic disorders

The development in neuroimaging techniques has revolutionized the way neurology is practiced, including neurologic disorders in tropics. Some diseases occur exclusively, whereas some are more common in tropical regions. However, some are becoming increasingly prevalent in the developed world too, as a result of patterns of human migration and globalization. It is imperative to learn about the role of imaging in tropical neurology, which might assist early diagnosis and treatment and also add to the existing knowledge. Infections are more common in the tropics and require special attention in view of their potential treatability.

Parasitic diseases of the central nervous system

This article reviews the characteristic imaging appearances of parasitic diseases of the central nervous system, including cysticercosis, toxoplasmosis, cystic echinococcosis, schistosomiasis, amebiasis, malariasis, sparganosis, paragonimiasis, and American and African trypanosomiases. Routine precontrast and postcontrast MR imaging helps in localization, characterization, delineation of extension, and follow-up of the parasitic lesions. Moreover, recently developed tools, such as diffusion, perfusion, and MR spectroscopy, help to differentiate parasitic diseases of the central nervous system from simulating lesions. Combining imaging findings with geographic prevalence, clinical history, and serologic tests is required for diagnosis of parasitic diseases of the central nervous system.

CNS hypoxia is more pronounced in murine cerebral than noncerebral malaria and is reversed by erythropoietin

Cerebral malaria (CM) is associated with high mortality and risk of sequelae, and development of adjunct therapies is hampered by limited knowledge of its pathogenesis. To assess the role of cerebral hypoxia, we used two experimental models of CM, Plasmodium berghei ANKA in CBA and C57BL/6 mice, and two models of malaria without neurologic signs, P. berghei K173 in CBA mice and P. berghei ANKA in BALB/c mice. Hypoxia was demonstrated in brain sections using intravenous pimonidazole and staining with hypoxia-inducible factor-1α-specific antibody. Cytopathic hypoxia was studied using poly (ADP-ribose) polymerase-1 (PARP-1) gene knockout mice. The effect of erythropoietin, an oxygen-sensitive cytokine that mediates protection against CM, on cerebral hypoxia was studied in C57BL/6 mice. Numerous hypoxic foci of neurons and glial cells were observed in mice with CM. Substantially fewer and smaller foci were observed in mice without CM, and hypoxia seemed to be confined to neuronal cell somas. PARP-1-deficient mice were not protected against CM, which argues against a role for cytopathic hypoxia. Erythropoietin therapy reversed the development of CM and substantially reduced the degree of neural hypoxia. These findings demonstrate cerebral hypoxia in malaria, strongly associated with cerebral dysfunction and a possible target for adjunctive therapy.

In the eye of experimental cerebral malaria

Cerebral malaria is the most severe complication of Plasmodium falciparum infection, accounting for 1 million deaths per year. We characterized the murine disease using in vivo magnetic resonance imaging (MRI) at 4.7 T, proving that ischemic edema is responsible for fatality. The aim of the present study was to identify early markers of experimental cerebral malaria using very high field conventional MRI (11.75 T). CBA/J mice infected with Plasmodium berghei ANKA were observed at an early stage of the disease, before the onset of detectable brain swelling and at the most acute stage of cerebral malaria. Herein, we report the first detection of damage to the optic and trigeminal nerves on T(2)-weighted MRI. The trigeminal nerves appeared hypointense, with significantly reduced diameter and cross-sectional area. The optic nerves were hypointense and often not visible. In addition, the internerve distance between the optic nerves was significantly and progressively reduced between the early and severest stages. Cranial nerve injury was the earliest anatomic hallmark of the disease, visible before brain edema became detectable. Thus, cranial nerve damage may manifest in neurologic signs, which may assist in the early recognition of cerebral malaria.

Magnetic resonance imaging in cerebral malaria: a report of four cases

OBJECTIVES

This is a retrospective institutional review of clinical data and radiological findings of cerebral malaria patients presenting to a tertiary centre in India, which is an known to be endemic for malarial disease.

METHODS

The present series describes MRI in four cases all of which revealed bithalamic infarctions with or without haemorrhages in patients with cerebral malaria, and this review examines a subset of patients with this condition. In addition, acute haemorrhagic infarctions were also seen the in brain stem, cerebellum, cerebral white matter and insular cortex in two of the four patients.

RESULTS

In this series, the patient with cerebellum and brain stem involvement died. The remaining three survived with antimalarial and supportive treatment. No neurological symptoms were noted on clinical follow-up. MRI follow-up was obtained in only one of the three patients (3 months post-treatment) and showed resolution of thalamic infarctions.

CONCLUSION

These imaging features may help in the early diagnosis of cerebral malaria so that early treatment can begin and improve the clinical outcome.

Rethinking cerebral malaria pathology

PURPOSE OF REVIEW

Intense interventions are ongoing to combat malaria. Malaria mortality investigation remains as an intense area of study with controversies, competing models of pathogenesis, and a few carefully proceeding clinical trials. This review suggests a reframing of the question of cerebral malaria pathology in light of recent findings to focus on dissection of pathogenesis that will lead to effective treatments.

RECENT FINDINGS

Pediatric and adult manifestations of cerebral malaria within the retina allows for intense study of the clinical defined patients including the advent of multiple imaging modalities in endemic regions. Basic pathogenesis in mouse models and human studies, focused on cytokines, inflammation, cytoadherence, and endothelial activation, continues to be elucidated molecule by molecule. Coagulation is variably important and may serve as one of several unifying principles of current pathogenesis models. Parasite-derived molecules - surface or soluble - remain necessary but not sufficient to explain pathologic manifestations.

SUMMARY

As we close the gaps in the fight against global malaria, the question of cerebral malaria mortality remains a source of great concern. We currently have no effective means of reversal of coma or impacting mortality in the comatose patient. As transmission is broken, cerebral malaria will spread to older age groups in Africa where we expect mortality will be higher. Continued directed study of pathogenesis with the primary goal of efficacious interventions in the comatose is a necessity.

Reversible splenial lesion syndrome in cerebral malaria

A 71-year-old Caucasian man living in Congo was investigated by serial magnetic resonance imaging (MRI) after having presented cerebral malaria due to Plasmodium falciparum. The clinical picture was characterized initially by coma and seizures. The patient developed multiple organ failure. There was, at 4 months follow-up only, a minimal neurological improvement consistent with minimally conscious state. The first cerebral MRI on day 17 showed a lesion of the splenium of corpus callosum with high signal intensity on DWI and FLAIR sequence and reduced ADC, and small cortical infarcts in the internal occipital regions. Follow-up MRI obtained 36 days later showed a complete resolution of splenial lesion, though without clinical improvement. Cerebral malaria should be added to the list of possible causes of reversible lesion of the splenium of corpus callosum.