Differential diagnosis of white matter diseases in the tropics: An overview

Juvenile Alexander Disease: A Rare Leukodystrophy

Alexander disease is an uncommon autosomal dominant leukodystrophy that influences the white matter of the central nervous system (CNS), predominantly affecting the frontal lobe bilaterally. The most obvious pathogenic hallmark is the extensive deposition of cytoplasmic inclusions known as "Rosenthal fibers" in perivascular, subpial, and subependymal astrocytes throughout the CNS. The hereditary cause is mutations in the glial fibrillary acidic protein (GFAP) gene. Infantile, adult, and juvenile onsets are the three subtypes. Psychomotor retardation, mile-stone regression, spastic paresis, brain stem symptoms (swallowing, speech, etc.), and seizures define the juvenile variety, which emerges between the ages of three and 10 years. Macrocephaly has a lower likelihood of being a juvenile type. It is generally diagnosed based on clinical and magnetic resonance imaging findings. A five-year-old girl is presented as a case of juvenile Alexander disease, with typical clinical and MRI features.

Early-Onset Multiple Sclerosis With Frequent Relapses: A Challenging Diagnosis With a Less Favorable Prognosis

Pediatric multiple sclerosis (MS) is a rare demyelinating disease of the brain, spinal cord, and optic nerve caused by immune modulators mediating against the neuronal axons of the central nervous system. MS is usually characterized by a series of neurological events, without any features of encephalopathy, separated in time and space. The complications arise from the permanent degeneration of the nerves. This condition can be diagnosed based on International Pediatric Multiple Sclerosis Study Group diagnostic criteria, and there is no definitive treatment for MS. We report the case of a male child who was diagnosed with MS at the age of six years when he presented with right hemiparesis and visual impairment. Subsequently, he had multiple relapses with varied neurological presentations, and each relapse was treated with methylprednisolone.

Rationalization of Using the MR Diffusion Imaging in B12 Deficiency

Context:

The structural imaging of brain does not demonstrate any changes in the vast majority of patients with vitamin B12 deficiency, even in the advanced stages.

Aims:

We investigated the microstructural changes in the brain with diffusion imaging among patients with biochemical evidence of B12 deficiency.

Patients and Methods:

We retrospectively analyzed all diffusion-weighted MRI images between the periods 2014–2016 who had biochemical evidence of B12. The age-sex matched controls were chosen from the group with normal B12 levels. Patients with pathological findings in conventional MRI images were excluded from the study.

Results:

About 37 patients were recruited (22 women, 15 men; mean age, 34.1 ± 9.9 years; age range). They were about thirty-four age-and sex-matched controls (with normal B12 levels), which were also included in the study. The mean apparent diffusion coefficient (ADC) value of amygdala (773.8 ± 49.9 vs. 742.2 ± 24.2, P = 0.01), hypothalamus (721.3 ± 39.2 vs. 700.2 ± 38.2, P = 0.02), striate cortex (737.6 ± 77.6 vs. 704.3 ± 58.2, P = 0.04), suprafrontal gyrus (740.7 ± 46.9 vs. 711.6 ± 40.7, P = 0.007) and medulla oblongata-olivary nucleus (787.3 ± 56.4 vs. 759.7 ± 46.2, P = 0.02) were significantly higher in B12 deficiency group compared to controls, whereas ADC values were similar at hippocampus, thalamus, insula, corpus striatum, cingulate gyrus, occipital gyrus, dentate nucleus, cerebral pedicle, tegmentum, pons, and posterior medulla oblongata.

Conclusions:

Our study indicates that a significant increase in ADC values occurs in multiple brain regions in patients with vitamin B12.

Novel Alanyl-tRNA Synthetase 2 Pathogenic Variants in Leukodystrophies

The white matter disease spectrum is associated with many genetic diseases, including AARS2, CADASIL, ALD, and others. In this study, to determine the novel alanyl-tRNA synthetase 2 mutation implicated in white matter disease, several families with an autosomal recessive inheritance pattern of white matter disease were analyzed by whole-exome sequencing. Variants were prioritized according to their rarity and pathogenic variants in genes already known to be associated with leukodystrophies and were confirmed by Sanger sequencing using standard protocols. We identified 5 rare variants (c.452T>C chr6:44279256 p.M151T, c.1871G>A chr6:44272054 p.W624X, c.802A>G chr6:44278128 p.M268V, c.1703-1704del chr6:-44272430-44272431 p.Q568fs, and c.179C>A chr6-44280882 p.P60H) with varying expression in 4 independent Chinese families with leukodystrophy. These single nucleotide variants (SNVs), or deletion mutations, each induced a frameshift, causing a missense mutation in alanyl-tRNA synthetase 2. These findings suggested that all mutations might contribute to the development of leukodystrophy in the examined family members. Combined with previous findings, our data confirmed that the novel mutations are located in leukodystrophy-related risk genes. We also summarized all the alanyl-tRNA synthetase 2 mutations related to the onset of leukodystrophies in adults.

Acute disseminated encephalomyelitis following varicella-zoster virus infection: Case report of effective treated both in clinical symptom and neuroimaging

INTRODUCTION

Acute disseminated encephalomyelitis (ADEM) is an idiopathic inflammatory demyelinating disorder of the central nervous system (CNS). Early treatment is the key for neurological recovery.

METHODS

A case of ADEM associated with varicella-zoster virus infection was presented, in which magnetic resonance imaging (MRI), cerebrospinal fluid (CSF) examinations were included.

RESULTS

Magnetic resonance imaging of the brain revealed multiple hyperintense lesions at the subcortical level on fluid-attenuated inversion recovery (FLAIR), and MRI of the spinal cord revealed longitudinally segmented hyperintense lesions at the spinal cord on T2-weighted images. The patient was treated with methylprednisolone and gancyclovir, and had a favorable recovery. Subsequent MRI of the brain and cervical cord showed the previous abnormal hyperintensities had markedly disappeared.

CONCLUSION

A rare case of ADEM with longitudinal segmented hyperintense lesions at the spinal cord on T2-weighted images was presented. Excellent response to ADEM treatment with high-dose steroids was reported resulting in a remarkable neurological recovery. A long-term follow-up is needed for prognosis.

Rare and unusual case of hepatic and disseminated tuberculosis in an immunocompetent patient

Mycobacterium tuberculosis complex disease (tuberculosis (TB)) of the liver is rare and liver abscesses as a result are even rarer. In an immunocompetent individual, the disease tends to be localised. To the best of our knowledge, we report one of the most severe TB involvements of the liver in an immunocompetent individual. A young woman with a history of previous TB infection, presented in septic shock. Scans showed a liver filled with possible abscesses, one of which was aspirated and confirmed TB. Multiple HIV tests were negative but she remained lymphopaenic. Although she improved substantially with anti-tuberculous treatment, she later developed non-tuberculous central nervous system disease that we were unable to fully explain. Despite a stormy recovery period, she continues to do well.

Wernicke's encephalopathy in a patient with gastric carcinoma: a diagnosis not to miss

We describe a case of a patient who presented with a 20-day history of vomiting, generalised weakness and loss of appetite and a 2-day history of altered sensorium. On examination, he was grossly emaciated and there were no palpable lymph nodes. Central nervous system examination revealed nystagmus with bilateral lateral recti palsy and abdominal examination showed mild hepatomegaly. MRI of the brain showed bilateral and symmetrical hypertense signal changes in T2-weighted and fluid-attenuated inversion recovery sequences with diffusion restriction in the paramedian ventromedial thalamus. These findings were compatible with Wernicke's encephalopathy. He was started on thiamine supplementation with which neurological signs improved. An ultrasound of the abdomen showed mild hepatomegaly with multiple hyperechoic lesions and wall thickening of the pyloric antrum. Upper gastroduodenoscopy showed ulcerative lesions involving the antrum, pylorus and duodenum. Biopsy revealed moderately differentiated adenocarcinoma. The patient underwent palliative gastrojejunostomy and was clinically better at discharge. It is important to consider Wernicke encephalopathy in patients with gastric cancer who have acute neurological symptoms.

Imaging and clinical properties of inflammatory demyelinating pseudotumor in the spinal cord

Inflammatory demyelinating pseudotumor usually occurs in the brain and rarely occurs in the spinal cord. On imaging, inflammatory demyelinating pseudotumor appears very similar to intramedullary tumors such as gliomas. It is often misdiagnosed as intramedullary tumor and surgically resected. In view of this, the clinical and magnetic resonance imaging manifestations and the pathological fea-tures of 36 cases of inflammatory demyelinating pseudotumor in the spinal cord were retrospec-tively analyzed and summarized. Most of these cases suffered from acute or subacute onset and exhibited a sensorimotor disorder. Among them, six cases were misdiagnosed as having intra-dullary gliomas, and inflammatory demyelinating pseudotumor was only identified and pathologi-cally confirmed after surgical resection. Lesions in the cervical and thoracic spinal cord were com-mon. Magnetic resonance imaging revealed edema and space-occupying lesions to varying grees at the cervical-thoracic junction, with a predominant feature of non-closed rosette-like forcement (open-loop sign). Pathological examination showed perivascular cuffing of predominantly dense lymphocytes, and demyelination was observed in six of the misdiagnosed cases. These re-sults suggest that tumor-like inflammatory demyelinating disease in the spinal cord is a kind of special demyelinating disease that can be categorized as inflammatory pseudotumor. These solitary lesions are easily confused with intramedullary neoplasms. Patchy or non-closed reinforcement (open-ring sign) on magnetic resonance imaging is the predominant property of inflammatory myelinating pseudotumor, and inflammatory cell infiltration and demyelination are additional pa-logical properties.