Teaching NeuroImage: Glutaredoxin-5-Associated Variant Nonketotic Hyperglycinemia.

A 5-year-old boy presented with subacute motor regression since age 2.5 years. Examination revealed spasticity of bilateral lower extremities, generalized dystonia, and pseudobulbar palsy. Investigations revealed raised plasma lactate (2.5 mmol/L, normal range 0.8-1.5 mmol/L) and no evidence of sideroblastic anemia. Neuroimaging showed cavitating leukoencephalopathy with involvement of long tracts (corticospinal, spinothalamic tracts) and dorsolateral columns of cervicothoracic cord (Figures 1 and 2). A next-generation sequencing test identified a novel homozygous missense variant (c.171C > A, p.Phe57Leu) in exon 1 of the Glutaredoxin-5 (GLRX5) gene.

Nonketotic Hyperglycinemia: Two Case Reports and Review.

Nonketotic hyperglycinemia (NKH) or glycine encephalopathy is an autosomal recessive disorder of glycine metabolism resulting in an excessive accumulation of glycine in all body tissues, including the central nervous system. It is caused by a biochemical defect in the glycine cleavage system and considered as a rare disorder with an estimated prevalence of 1:60,000. The neonatal form presents in the first few days of life with progressive encephalopathy, hypotonia, myoclonic jerks, hiccups, seizures, rapid progression to coma and often death due to central apnea. Surviving infants often have severe developmental delay and refractory seizures. Atypical forms of NKH present with heterogeneous and nonspecific disease course. Classical glycine encephalopathy usually carries a very poor prognosis. We describe two neonates who presented with neonatal encephalopathy, apnea, and progressive lethargy. Increased CSF glycine level along with an elevated CSF to plasma glycine ratio was suggestive of classic NKH. Burst suppression EEG and agenesis of the corpus callosum were supportive findings. Evolution of the EEG patterns and course of the disease are discussed in detail. Transient phases of clinical stabilization and normalized plasma biochemical results may not necessarily reflect the actual encephalopathic process. Serial EEGs are helpful to assess the efficacy of treatment and to modify the therapeutic approach.

Brain imaging in classic nonketotic hyperglycinemia: Quantitative analysis and relation to phenotype.

Patients with severe nonketotic hyperglycinemia (NKH) have absent psychomotor development and intractable epilepsy, whereas attenuated patients have variable psychomotor development and absent or treatable epilepsy; differences in brain magnetic resonance imaging (MRI) between phenotypes have not been reported. In a retrospective cross-sectional study, we reviewed 38 MRI studies from 24 molecularly proven NKH patients, and 2 transient NKH patients. Quantitative analyses included corpus callosum size, apparent diffusion coefficient, automated brain volumetric analysis, and glycine/creatine ratio by spectroscopy. All patients age <3 months had restricted diffusion in the posterior limb of the internal capsule, anterior brainstem, posterior tegmental tracts, and cerebellum, not present in transient NKH. In older infants, the pattern evolved and included generalized diffusion restriction in the supratentorial white matter, which quantitatively peaked between 3 and 12 months. No patient had absent corpus callosum or gyral malformation. The corpus callosum was relatively short in severe compared to attenuated phenotypes, and thin in severe cases only. The corpus callosum growth rate differed by severity; age-matched Z-scores of thickness worsened in severe cases only. Cerebral volume was decreased in the hippocampus, globus pallidus, cerebral cortex, thalamus, and cerebellum. Severe patients had greatest glycine/creatine ratios. In this study, no brain malformations were identified. The growth failure of the corpus callosum is worse in severe NKH, whereas the diffusion restriction pattern, reflecting microspongiosis, does not discriminate by phenotypic severity. NKH is therefore a disorder of brain growth best recognized in the corpus callosum, whereas spongiosis is not prognostic.

Hyperglycemic Nonketotic Signal Changes of the Striatum: An Unusual Complication in the Setting of Neurosurgical Procedures.

BACKGROUND: Hyperglycemic nonketotic chorea is an uncommon complication of poorly controlled diabetes mellitus. Patients typically develop abnormal signal changes in the striatum on imaging studies. Whereas the condition is well reported in the medical literature, reports on this topic in the surgical literature are lacking. CASE DESCRIPTION: We report the first case of striatal hyperglycemic nonketotic signal changes occurring in the setting of a frontotemporal craniotomy for resection of a sphenoid wing meningioma. Postoperative magnetic resonance imaging (MRI) of the patient demonstrated restricted diffusion within the bilateral caudate nuclei, globus pallidus, putamen, and thalami in response to intraoperative hyperglycemia. Normalization of the patient's serum glucose levels postoperatively was followed by improvement in the radiographic abnormalities and their associated clinical sequelae. At the patient's last follow-up appointment 5 months after surgery, MRI demonstrated complete resolution of the abnormal signal changes to the patient's neurologic baseline. CONCLUSIONS: Although uncommon, striatal signal changes associated with nonketotic hyperglycemia should be recognized as a potential complication of surgery. Knowledge of this rare entity is important so that tight control of perioperative serum glucose can be achieved in diabetic patients to prevent this rare entity.

Nonketotic hyperglycinemia: spectrum of imaging findings with emphasis on diffusion-weighted imaging.

PURPOSE: The purpose of this study was to explore brain abnormalities in nonketotic hyperglycinemia (NKH) using diffusion-weighted imaging (DWI) and when feasible, diffusion tensor imaging (DTI) and tractography. METHODS: Seven patients with confirmed diagnosis of NKH (8 days-2 years) underwent brain MRI. Conventional T1 and T2WI were acquired in all patients, DWI in six and DTI and tractography in two (4 months and 2 years). Measurements of fractional anisotropy (FA), radial diffusivity (RD), axial diffusivity (AD) and Trace from eight white matter regions were compared between the two patients and age-matched controls. Tractography of corpus callosum, superior longitudinal fasciculus and corticospinal tracts was performed with extraction of their FA and diffusivity indices. RESULTS: MRI showed nonspecific brain atrophy in three children. Corpus callosum atrophy was found as a part of these atrophic changes. Cerebellar vermian hypoplasia and supratentorial hydrocephalus were seen in one patient. The topographic distribution of diffusion restriction was different among patients. The affected white matter regions were not predominantly following the expected areas of myelination according to patients' age. Deep grey matter nuclei were affected in one patient. DTI revealed lower FA with higher RD in most of the measured white matter regions and tracts. These changes were more appreciated in the 2-year-old patient. However, Trace was higher in the 2-year-old patient and lower in the 4-month-old one. The extracted tracts were decreased in volume. CONCLUSION: DWI, DTI and tractography with FA and diffusivity measurements can give insights into white matter microstructural alterations that can occur in NKH.

[A stroke mimic: hemichorea associated with non-ketotic hyperglycaemia].

An 85-year-old man with a history of diabetes was admitted with acute onset hemichorea. Laboratory findings confirmed poorly controlled diabetes. A brain computed tomography (CTC) revealed contralateral striatal hyperdensity. The findings were compatible with hyperglycaemia-induced hemichorea, and antidiabetic and symptomatic treatment was initiated. The symptoms remitted completely after six days, and a follow-up CTC showed partial resolution of the striatal changes. This case illustrates the importance of considering if hyperglycaemia is the cause of hemichorea, as early diagnosis and treatment yield an excellent prognosis.

Hemichorea caused by nonketotic hyperosmolar state: A case report and review of the literature.

Our report involves a case of hemichorea caused by the nonketotic hyperosmolar state. We have analyzed the clinical data and relevant features of a patient who presented herself to the Affiliated Hospital of Xuzhou Medical University. The patient had unilateral involuntary movements for 1 month. We discovered that her blood glucose levels were very high. The patient underwent computed tomography (CT), magnetic resonance imaging (MRI), and magnetic resonance angiography (MRA), indicating right basal ganglia lesion. Control of the patient's blood glucose plus supportive treatment resulted in a significant improvement of her clinical state.

Non-ketotic hyperglycaemia presenting as epilepsia partialis continua.

Epilepsia partialis continua is a rare epileptic syndrome observed in patients with brain structural lesions and metabolic disorders. We report a patient with non-ketotic hyperglycaemia presenting as epilepsia partialis continua with reversible focal brain lesions. An 83-year-old woman visited our hospital due to sudden and repetitive left facial twitching lasting for two days. Initial laboratory data revealed serum glucose, osmolality, and sodium levels of 631 mg/dl, 310 mOsm/l, and 130 mEq/l, respectively. EEG was normal. Brain MRI showed low signal changes in the right frontal subcortical area and high signal changes in the surrounding right frontal cortical areas on T2-weighted, fluid-attenuated inversion recovery, and diffusion-weighted images. No seizures recurred after correcting blood glucose levels, hydrating the patient, and infusing valproate (900 mg/day). Follow-up MRI, six months later, showed complete resolution of the signal changes in the right frontal cortical and subcortical areas and no clinical seizures. When considering non-ketotic hyperglycaemia with epilepsia partialis continua in an elderly patient, early diagnosis and administration of the appropriate therapy is very important in order to decrease morbidity.

[Hemichorea with Contralateral High Signal Intensity Putaminal Lesion on T1-Weighted Images in Non-Ketotic Hyperglycemia]. / Hemichorea mit T1-hyperintenser Signalalteration im kontralateralen Putamen bei nichtketotischer Hyperglykämie.

A 64-year-old diabetic female patient presented with involuntary unilateral hyperkinetic movements of the left limbs. Cranial MRI showed a contralateral high signal intensity putaminal lesion on T1-weighted images without any signal changes in the T2-weighted images. This finding is characteristic for hemichorea-hemiballism associated with insufficiently treated diabetes mellitus. Additionally, proton MR spectroscopy was performed and revealed a decreased N-acetylaspartate/creatine and N-acetylaspartate/choline ratio, indicating neuronal damage of the contralateral putamen.

Diabetic nonketotic hyperosmolar state: interesting imaging observations in 2 patients with involuntary movements and seizures.

We report two patients of diabetic nonketotic hyperosmolar state presenting acutely with "self-limiting hemichorea - hemiballismus" and "generalized convulsive status epilepticus". CT scan in both the patients revealed a hyperdense nonenhancing basal ganglia. Magnetic resonance imaging brain of patient 1 showed it to be hyperintense on T1W image and iso-hyper intense on T2W image, minimally enhancing with contrast injection.

Prenatal diagnosis of hypoplasia of the corpus callosum in association with non-ketotic hyperglycinemia.

Abnormalities of the corpus callosum are often associated with a poor prognosis due to the anatomical defect itself and associated anomalies that include malformations and inherited metabolic disorders. We report a case of the prenatal diagnosis of hypoplasia of the corpus callosum that was associated with non-ketotic hyperglycinemia. Metabolic disorders are a known association with corpus callosum abnormalities and carry a dismal prognosis. A diagnosis of non-ketotic hyperglycinemia should be considered when a fetus presents with an abnormality of the corpus callosum. A literature search reviews other inherited diseases associated with hypoplasia of the corpus callosum.

Acute hydrocephalus in nonketotic hyperglycinemia.

We present four patients with typical neonatal onset non-ketotic hyperglycinemia (NKH) who developed hydrocephalus requiring shunting in early infancy. Brain imaging revealed acute hydrocephalus, a megacisterna magna or posterior fossa cyst, pronounced atrophy of the white matter, and an extremely thin corpus callosum in all. The three older patients had profound developmental disabilities. This suggests that the development of hydrocephalus in NKH is an additional poor prognostic sign.