Transient Homonymous Superior Quadrantanopsia in Nonketotic Hyperglycemia: A Case Report and Systematic Review

The Dark side of the White Matter. Diffuse subcortical White Matter Hypointensity on T2/FLAIR: A systematic review of a frequently underrecognized sign

BACKGROUND AND OBJECTIVES

Many reversible brain MRI abnormalities have been described, among these the most frequently reported are cortical hyperintensities on FLAIR/T2 occurring during seizures. Much less attention has been given to those situations where White Matter goes Dark: subcortical white matter hypointensity on T2/FLAIR. Our aim is to identify the medical condition "Dark White Matter" (DWM) is more frequently associated with. This is the first systematic review on DWM.

METHODS

PubMed was searched in August 2023. Included studies were those reporting Diffuse Subcortical White Matter Hypointensity on T2/FLAIR. Mainly case reports were included. Individual patient-level data was included whenever available. Frequency measures of the different diseases were calculated.

RESULTS

56 studies were included, 228 patients were eligible for analysis. DWM happened in isolation, with no cortical abnormalities, in 71 cases and was associated with seizures in >61.4% of cases. The most frequently DWM-associated disease was Non-Ketotic Hyperglycaemic hyperosmolar state (NKH), followed by Encephalitis, Moyamoya disease, Genetic Causes, and Subdural Hematoma. Frequency of NKH was 32%. NKH was associated with seizures in 100% of cases and the most frequently involved lobe was the occipital one. When considering only the subgroup of patients with seizures, DWM was indicative of NKH in 51.4% of cases and Encephalitis in 26.4% of cases. Key limitations are heterogeneity and missing data.

DISCUSSION

DWM is frequently underdiagnosed. This sign can exist alone and it is not merely a consequence of cortical involvement. Moreover, it has important implications, both diagnostic and therapeutic, as it is more frequently associated with NKH, especially in the context of seizures, where anti-seizure medication is not the first line of treatment. We also discuss the pathogenesis of DWM by finding a common link between the most frequently associated diseases.

Acute stroke-like deficits associated with nonketotic hyperglycemic hyperosmolar state: an illustrative case and systematic review of literature

Introduction

Nonketotic hyperglycemic hyperosmolar state (NKHHS) is associated with a wide spectrum of neurological syndromes including acute stroke-like deficits. Clinical features and etiology have not been established yet.

Methods

Here we provide a case illustration and systematic review on non-epileptic acute neurological deficits in NKHSS. The systematic literature search followed PRISMA guidelines and a predefined protocol, including cases of NKHSS with acute stroke-like presentation.

Results

The database search yielded 18 cases. Hemianopia was the most common clinical presentation (73%), followed by partial or total anterior circulation syndrome (26%). Patients with symptoms of acute anterior circulation infarct were significantly older (69.5 ± 5.1 vs. 52.2 ± 13.9 years; p = 0.03) and showed higher mean glucose levels at the admission vs. those with hemianopia (674.8 ± 197.2 vs. 529.4 ± 190.8 mg/dL; p = 0.16). Brain MRI was performed in 89% of patients, resulting abnormal in 71% of them, especially hemianopic (91%). Subcortical hypointensities in T2-FLAIR MR sequences were present in all the analyzed cases. Cortical DWI hyperintensities were also common (64%). EEG showed diffuse or focal slow wave activity in 68% of patients, especially with visual hallucinations (85%). Neurological symptoms completely resolved in 78% of patients within 6 (IQR 3–10) days, following aggressive treatment and glucose normalization.

Conclusions

Our results suggest neuronal dysfunction on a metabolic basis as the leading cause of acute neurological deficits in NKHHS. Despite the generally favorable prognosis, prompt identification and aggressive treatment are crucial to avoid irreversible damage. Larger cohort studies are needed to confirm our findings.