Diffusion-Weighted MR Imaging in a Prospective Cohort of Children with Cerebral Malaria Offers Insights into Pathophysiology and Prognosis

BACKGROUND AND PURPOSE

Validation of diffusion-weighted images obtained on 0.35T MR imaging in Malawi has facilitated meaningful review of previously unreported findings in cerebral malaria. Malawian children with acute cerebral malaria demonstrated restricted diffusion on brain MR imaging, including an unusual pattern of restriction isolated to the subcortical white matter. We describe the patterns of diffusion restriction in cerebral malaria and further evaluate risk factors for and outcomes associated with an isolated subcortical white matter diffusion restriction.

MATERIALS AND METHODS

Between 2009 and 2014, comatose Malawian children admitted to the hospital with cerebral malaria underwent admission brain MR imaging. Imaging data were compiled via NeuroInterp, a RedCap data base. Clinical information obtained included coma score, serum studies, and coma duration. Electroencephalograms were obtained between 2009 and 2011. Outcomes captured included death, neurologic sequelae, or full recovery.

RESULTS

One hundred ninety-four/269 (72.1%) children with cerebral malaria demonstrated at least 1 area of diffusion restriction. The most common pattern was bilateral subcortical white matter involvement (41.6%), followed by corpus callosum (37.5%), deep gray matter (36.8%), cortical gray matter (17.8%), and posterior fossa (8.9%) involvement. Sixty-one (22.7%) demonstrated isolated subcortical white matter diffusion restriction. These children had lower whole-blood lactate levels (OR, 0.9; 95% CI, 0.85-0.98), were less likely to require anticonvulsants (OR, 0.6; 95% CI, 0.30-0.98), had higher average electroencephalogram voltage (OR, 1.01; 95% CI, 1.00-1.02), were less likely to die (OR, 0.09; 95% CI, 0.01-0.67), and were more likely to recover without neurologic sequelae (OR, 3.7; 95% CI, 1.5-9.1).

CONCLUSIONS

Restricted diffusion is common in pediatric cerebral malaria. Isolated subcortical white matter diffusion restriction is a unique imaging pattern associated with less severe disease and a good prognosis for full recovery. The underlying pathophysiology may be related to selective white matter vulnerability.

Brain imaging in normal kids: a community-based MRI study in Malawian children

OBJECTIVE

To collect normative MRI data for effective clinical and research applications. Such data may also offer insights into common neurological insults.

METHODS

We identified a representative, community-based sample of children aged 9-14 years. Children were screened for neurodevelopmental problems. Demographic data, medical history and environmental exposures were ascertained. Eligible children underwent the Neurologic Examination for Subtle Signs (NESS) and a brain MRI. Descriptive findings and analyses to identify risk factors for MRI abnormalities are detailed.

RESULTS

One hundred and two of 170 households screened had age-appropriate children. Two of 102 children had neurological problems - one each with cerebral palsy and epilepsy. Ninety-six of 100 eligible children were enrolled. Mean age was 11.9 years (SD 1.5), and 43 (45%) were boys. No acute MRI abnormalities were seen. NESS abnormalities were identified in 6 of 96 children (6%). Radiographic evidence of sinusitis in 29 children (30%) was the most common MRI finding. Brain abnormalities were found in 16 (23%): mild diffuse atrophy in 4 (4%), periventricular white matter changes/gliosis in 6 (6%), multifocal punctuate subcortical white matter changes in 2 (2%), vermian atrophy in 1 (1%), empty sella in 3 (3%) and multifocal granulomas with surrounding gliosis in 1 (1%). Having an abnormal MRI was not associated with age, sex, antenatal problems, early malnutrition, febrile seizures, an abnormal neurological examination or housing quality (all P values >0.05). No predictors of radiographic sinusitis were identified.

CONCLUSION

Incidental brain MRI abnormalities are common in normal Malawian children. The incidental atrophy and white matter abnormalities seen in this African population have not been reported among incidental findings from US populations, suggesting Malawi-specific exposures may be the cause.

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.