Imaging of Acquired Metabolic and Toxic Disorders of the Basal Ganglia

Epilepsy in sulfite oxidase deficiency and related disorders: insights from neuroimaging and genetics

Sulfite oxidase deficiency (SOD) and related disorders, especially molybdenum cofactor deficiency (MoCD), are a group of rare and severe neurometabolic disorders caused by gene mutations that affect the sulfur-containing amino acid catabolic pathway. These disorders are characterized by distinctive neuroimaging features such as diffuse cerebral atrophy, multicystic encephalomalacia, and ventriculomegaly in early infancy. These features are essential for early diagnosis and treatment. Moreover, the genetics of these disorders are complex but have been increasingly elucidated in the era of molecular medicine. Therefore, we reviewed 28 articles (published from January 1967 until October 2021) on SOD and MoCD, focusing on their neuroimaging and genetic aspects. We highlighted the differences between SOD and MoCD and other conditions that may mimic them, such as common neonatal hypoxic-ischemic encephalopathy and uncommon neonatal metabolic disorder (Leigh syndrome). We also summarized the current knowledge on the genetic mechanisms and the manifestation of seizure disorders of SOD and MoCD. In conclusion, if clinical, neuroimaging, and neuropathological findings suggest a possible SOD or related disorder; extensive molecular diagnostics should be performed to confirm the diagnosis.

The extrapyramidal syndromes of chronic kidney disease and dialysis (EPS-CKDD): diagnostic criteria, risk factors and prognosis

BACKGROUND

Acute extrapyramidal movement disorders in dialysis patients are rare, inconsistently defined and have uncertain aetiology and prognosis.

AIM

Define diagnostic criteria, prognosis and risk factors.

DESIGN AND METHODS

Retrospective case series review of 20 patients (14 female, mean age 62 years) receiving dialysis for a median of 15 (interquartile range 4-35) months who presented with acute parkinsonism (AP = 11) or chorea/athetosis (CA = 9).

RESULTS

All patients had type 2 diabetes (HbA1c 6.8 ± 1.0) and had received metformin. Lactic acidosis was present in 2 patients at presentation and serum lactate was elevated in 7/15 patients tested. No patient had abnormal copper or thyroid metabolism and 5/8 patients tested returned marginal abnormalities in heavy metal screening. Magnetic resonance imaging (MRI) revealed characteristic bilateral symmetric T2 hyperintensity of the basal ganglia (BG), predominantly putamen and globus pallidus (the lentiform nucleus) and more extensive involvement of the external and internal capsules in patients with AP presentation. Post-mortem demonstrated cytotoxic necrosis of the BG. Therapy included thiamine, intensive dialysis and cessation of metformin. Two patients died acutely, nine recovered and nine had residual symptoms. Median survival did not differ by presentation: AP 24 [95% confidence interval (CI) 21-27] and CA 33 (95% CI 32-35) months, P = 0.21.

CONCLUSIONS

There are two distinct clinical extrapyramidal movement disorders associated with specific diagnostic MRI imaging that support the diagnosis of the extrapyramidal syndromes of chronic kidney disease and dialysis. The associations with diabetes, metformin and metabolic acidosis suggest a common pathogenic mechanism but require additional study. Early recognition and treatment may improve outcomes.

Potentially Reversible and Recognizable Acute Encephalopathic Syndromes: Disease Categorization and MRI Appearances

"Encephalopathy" is a vague term that encompasses varying definitions, often with a nonspecific clinical presentation and numerous possible pathophysiologic causes. Hence, MR imaging plays a crucial role in the early diagnosis and treatment by identifying imaging patterns when there is limited clinical history in such patients with acute encephalopathy. The aim of this review was to aid in remembrance of etiologies of potentially reversible acute encephalopathic syndromes on MR imaging. The differential includes vascular (reversible cerebral vasoconstriction syndrome, transient global amnesia, disseminated intravascular coagulation, and thrombotic microangiopathy), infection (meningitis, encephalitis), toxic (posterior reversible encephalopathy syndrome, acute toxic leukoencephalopathy; carbon monoxide, alcohol-related, medication- and illicit drug-related toxic encephalopathies), autoimmune, metabolic (osmotic demyelination syndrome, uremic, acute hepatic encephalopathy), idiopathic/inflammatory (stroke-like migraine attacks after radiation therapy syndrome), neoplasm-related encephalopathy, and seizure-related encephalopathy.

Neuroimaging of Patients in the Intensive Care Unit: Pearls and Pitfalls

A brief introduction is provided of the different imaging modalities encountered in the intensive care unit (ICU). The spectrum of intracranial pathology as well as potential postsurgical complications is reviewed, with a focus on pearls and pitfalls. A brief overview also is provided of imaging of the spine in an ICU patient.

Bilateral striatal necrosis due to homoplasmic mitochondrial 3697G>A mutation presents with incomplete penetrance and sex bias

Background

Heteroplasmic mitochondrial 3697G>A mutation has been associated with leber hereditary optic neuropathy (LHON), mitochondrial encephalopathy, lactic acidosis and stroke‐like episodes (MELAS), and LHON/MELAS overlap syndrome. However, homoplasmic m.3697G>A mutation was only found in a family with Leigh syndrome, and the phenotype and pathogenicity of this homoplasmic mutation still need to be investigated in new patients.

Methods

The clinical interviews were conducted in 12 individuals from a multiple‐generation inherited family. Mutations were screened through exome next‐generation sequencing and subsequently confirmed by PCR‐restriction fragment length polymorphism. Mitochondrial complex activities and ATP production rate were measured by biochemical analysis.

Results

The male offspring with bilateral striatal necrosis (BSN) were characterized by severe spastic dystonia and complete penetrance, while the female offspring presented with mild symptom and low penetrance. All offspring carried homoplasmic mutation of NC_012920.1: m.3697G>A, p.(Gly131Ser). Biochemical analysis revealed an isolated defect of complex I, but the magnitude of the defect was higher in the male patients than that in the female ones. The ATP production rate also exhibited a similar pattern. However, no possible modifier genes on the X chromosome were identified.

Conclusion

Homoplasmic m.3697G>A mutation could be associated with BSN, which expanded the clinical spectrum of m.3697G>A. Our preliminary investigations had not found the underlying modifiers to support the double hit hypothesis, while the high level of estrogens in the female patients might exert a potential compensatory effect on mutant cell metabolism.