Reye's syndrome with cortical laminar necrosis: MRI

Acute hepatic encephalopathy presenting as cortical laminar necrosis: case report

We report on a 55-year-old man with alcoholic liver cirrhosis who presented with status epilepticus. Laboratory analysis showed markedly elevated blood ammonia. Brain magnetic resonance imaging (MRI) showed widespread cortical signal changes with restricted diffusion, involving both temporo-fronto-parietal cortex, while the perirolandic regions and occipital cortex were uniquely spared. A follow-up brain MRI demonstrated diffuse cortical atrophy with increased signals on T1-weighted images in both the basal ganglia and temporal lobe cortex, representing cortical laminar necrosis. We suggest that the brain lesions, in our case, represent a consequence of toxic effect of ammonia.

Pediatric Inflammatory Diseases

Some rare neurological diseases affecting children have no well defined etiology and pathogenetic mechanisms. In this article diseases like Reye syndrome, Behçet disease, pediatric neurosarcoidosis, Posterior Reversible Encephalopathy Syndrome are described. Some of the main neuroradiological differential aspects are also critically considered. Reye syndrome is characterized by symmetric thalamic, white matter and basal ganglia lesions, in children with recent history of salycilates or immunosuppressive drugs intake. The most typical MRI feature of neurosarcoidosis is basilar meningeal thickening and enhancement with intraparenchymal enhancing nodules and white matter focal abnormalities. The classical distribution of lesions helps differential diagnosis with infectious meningoencephalitis. Differential diagnosis with relapsing-remitting multiple sclerosis his helped by the evidence of meningeal abnormalities. Neuro-Behçet is characterized by mesodiencephalic lesions in children with encephalopathy and coexistence of oral and genital ulcers and ocular abnormalities. PRES can be differentiated from vasculitis for the typical posterior white matter involvement and the different clinical features.

Magnetic resonance imaging findings in Reye syndrome: case report and review of the literature

Magnetic resonance imaging findings in Reye syndrome have been reported only infrequently. A previously well 8-year-old boy presented with repeated episodes of vomiting and abdominal pain followed by altered sensorium and tonic spasms. This occurred 5 days after upper respiratory tract infection. His laboratory data revealed elevated liver enzymes, prolonged prothrombin time, and high blood ammonia levels. Magnetic resonance imaging of the brain done on the day of admission revealed diffuse cerebral edema and signal alterations in brainstem, bilateral thalami, medial temporal lobes, parasagittal cortex, and cerebellar and subcortical white matter. Diffusion restriction was seen in thalami, midbrain, cerebellar white matter, subcortical white matter, and parasaggital cortex in the watershed territory. The patient made a full recovery. Follow-up magnetic resonance imaging after a week revealed complete resolution of all except thalamic lesions. Although diffusion restriction in thalami and midbrain has been reported previously, this is the first report indicating diffusion restriction in subcortical white matter and the parasagittal cortex.

Susceptibility-weighted imaging findings of cortical laminar necrosis in pediatric patients

BACKGROUND AND PURPOSE

MR susceptibility-weighted imaging (SWI) is a highly sensitive technique for detection of hemorrhage, but its utility in the evaluation of children with laminar necrosis is not yet known. We assessed whether cortical laminar necrosis in pediatric patients contains hemorrhage on SWI.

MATERIALS AND METHODS

"Cortical laminar necrosis" was defined as a hyperintense cortical lesion on T1-weighted imaging in the subacute or chronic phase of brain damage in some foci involving the cerebral cortex and white matter such as hypoxic-ischemic incidents and encephalopathy. Medical records, CT, and MR images were retrospectively analyzed. Fifteen patients (7 boys, 8 girls; age range, 0-13 years) were included. The areas of signal-intensity loss on SWI that were considered to be hemorrhage were correlated with the laminar necrosis. CT was assessed to correlate with the presence of calcification at the location of the signal-intensity loss on SWI. To assess appearance or signal-intensity changes of hemorrhage in the laminar necrosis, follow-up SWI was performed.

RESULTS

The causes of laminar necrosis included infarction in 4 patients, ischemic changes from Moyamoya disease in 2, meningoencephalitis in 2, hypoxic-ischemic encephalopathy in 2, shaken baby syndrome in 1, encephalopathy from severe infection in 1, status epilepticus in 1, citrullinemia in 1, and brain injury with posterior reversible encephalopathy syndrome in 1. T1-weighted imaging showed focal laminar necrosis in 8, multifocal laminar necrosis in 2, and diffuse laminar necrosis in 5. SWI findings correlated with laminar necrosis included the following: no hemorrhage in 13 patients (80.0%), dotted hemorrhage in 2 (13.3%), and laminar hemorrhage in 1 (6.7%). Follow-up SWI performed in 6 patients showed no additional hemorrhage.

CONCLUSION

Most areas of cortical laminar necrosis in pediatric patients showed no hemorrhage on SWI.

Klüver-Bucy syndrome following status epilepticus associated with hepatic encephalopathy

Described here is the case of a patient with liver cirrhosis who developed bilateral temporo-occipital lobe lesions on MRI and Klüver-Bucy syndrome following status epilepticus. Herpes encephalitis, paraneoplastic syndrome, Hashimoto's encephalopathy, reversible posterior leukoencephalopathy syndrome, mitochondrial encephalomyopathy, lactic acidosis, and strokelike episode syndrome were judged not to be involved on the basis of laboratory results. The possible cause of the temporo-occipital lesions on MRI in this patient was cortical damage related mainly to status epilepticus and partially to coexisting hepatic encephalopathy.

Acute Encephalitis of Unknown Etiology: Early Diagnosis and Follow-up of Disease Evolution. MRI

Two women with viral encephalitis of unknown etiology were studied with serial MR studies at 1.5 Tesla using: Spin-Echo (SE) T1-weighted (T1w) sequences before and after i.v. administration of paramagnetic contrast agent, with/without magnetization transfer (MT), Fast SE and Fluid-attenuated Inversion Recovery (FLAIR) T2-weighted sequences, Echo-Planar Single-Shot sequences for the assessment of water diffusivity (Diffusion Weighted, DW, and Apparent Diffusion Coefficient maps, ADC). The DW and T1w sequences with MT after contrast were most useful to detect the initial pathologic alterations, thereby reinforcing the clinical diagnostic hypothesis and prompting appropriate drug treatment, even if the laboratory data were not conclusive for viral etiology. In a later phase, both cases showed MR evidence of lacunar foci in the grey matter, and cortical laminar necrosis, probably indicating a concomitant hypoxic/ischemic mechanism.

Viral diseases of the central nervous system

Viral diseases of the central nervous system encompass a wide range of different processes, mainly inflammation affecting the brain (encephalitis), the meninges (meningitis), or a combined meningoencephalitis. The spinal cord can be affected as well (myelitis). Another group of viral-related disorders, sometimes without a clear pathophysiological mechanism disclosed, include post-viral illnesses. All of these groups of diseases are discussed in this article, with an emphasis on their imaging presentation, using magnetic resonance imaging.

Magnetic resonance imaging of cerebral cortical necrosis (polioencephalomalacia) in a dog

A 3-year-old neutered female mixed breed dog was examined because of severe, generalized seizure activity, tetraparesis, and encephalopathic signs. Cerebrospinal fluid (CSF) evaluation was unremarkable except for a mild increase in protein. Serum and CSF titers for infectious diseases were negative. Magnetic resonance (MR) imaging examination of the brain was performed and lesions were found within the cerebral gray matter of the temporal and parietal lobes. The lesions had increased signal intensity on T1, T2, and proton density-weighted images. There was mild inhomogeneous enhancement following intravenous contrast medium administration. Neurologic status improved and the seizures were well controlled, but the dog never regained normal mentation and euthanasia was performed 10 weeks after initial evaluation. At necropsy, severe cerebral cortical necrosis was found in the regions corresponding to the lesions seen on MR imaging examination. Large numbers of fat-containing macrophages (gitter cells) were found within these areas, and are thought to be responsible for the characteristic hyperintensity seen on the MR images.

Laminar cortical necrosis in central nervous system lupus: sequential changes in MR images

A 44-year-old woman with systemic lupus erythematosus developed central nervous system lupus presenting with headache, fever, cloudiness of consciousness, and psychotic symptoms. T1-weighted and proton MR images showed laminar high intensity lesions in the parietal and temporal cortex bilaterally. T2-weighted images of the lesions showed low signal intensity. Treatment with corticosteroids alleviated the clinical symptoms within 7 months. The low T2 and high T1 signal abnormalities disappeared in a year and in 5 years, respectively. The laminar cortical lesions on MR images were suggested to represent cortical necrosis associated with central nervous system lupus.