Occipital lobe seizures and subcortical T2 and T2* hypointensity associated with nonketotic hyperglycemia: a case report

Abstract

BackgroundNonketotic hyperglycemia often causes seizures. Recently, seizures associated with nonketotic hyperglycemia have been found to be associated with subcortical T2 hypointensity on magnetic resonance imaging, especially in the occipital lobes. However, the mechanism remains unclear, although iron accumulation is suggested. We present a case of occipital lobe seizures associated with nonketotic hyperglycemia supporting the hypothesis that the mechanism of subcortical T2 hypointensity is iron accumulation using gradient-echo T2*-weighted magnetic resonance imaging.Case presentationA 65-year-old Japanese man complained of intermittent pastel-colored flashing lights. On neurological examination, he also had lower right-side quadrant hemianopia. No other abnormal neurological findings were found. On laboratory analysis, his blood glucose level was 370 mg/dL, HbA1c was 11.4 %, and serum osmolarity was 326 mOsm/L. No ketones were detected in urine. A magnetic resonance imaging scan of his head showed subcortical T2 and T2* hypointensity in his left occipital lobe. Single-photon emission computed tomography with I123-N-isopropyl-iodoamphetamine revealed hyperperfusion in the left dominant occipital lobe. These magnetic resonance imaging abnormalities resolved during clinical recovery and treatment to control his blood sugar level. Therefore, a diagnosis of occipital lobe seizures associated with nonketotic hyperglycemia was made.ConclusionsTo the best of our knowledge, this is the first case of occipital lobe seizures associated with nonketotic hyperglycemia supporting the role of iron accumulation as a mechanism for subcortical T2 hypointensity using T2*-magnetic resonance imaging.

Left Homonymous Hemianopia: An Uncommon, Neuro-ophthalmological Presentation of Hyperglycemic Hyperosmolar State

“…In one report, disrupted blood brain barrier (BBB) as evident on delayed gadolinium enhancement in FLAIR images, was suggested to play a role in seizure formation in this setting [7]. Sasaki et al, suggest that long-standing hyperglycemia, rather than HHS per say, is the trigger for seizure as their patient did not meet diagnostic criteria of HHS [8].…”

Magnetic resonance imaging findings in patients with non-ketotic hyperglycaemia and focal seizures

“…3,5 Previous studies and reported cases of patients with slightly elevated serum osmolarity suggest the role of long-standing hyperglycaemia with abnormal HbA1c levels in inducing seizures, rather than an acute hyperglycaemic hyperosmolar state. 4,6,7 NKH-induced seizures are mostly of a focal motor type with or without secondary generalisation. Cases of epilepsia partialis continua and visual occipital lobe seizures have been described.…”

“…The transient iron accumulation may explain the corresponding hypointensity sometimes seen on T2*-weighted or SWI images. 7,17 Early post-ictal brain MRI shows brain abnormalities that involve mostly the cortical grey matter. Cortical hyperintensity on T2/FLAIR images with restricted diffusion, often associated with gyral or leptomeningeal gadolinium enhancement, are widely reported in association with seizures.…”

“…On the other hand, focal subcortical hypointensity on T2-weighted/FLAIR images has been reported as an uncommon MRI finding related to seizures, but it is broadly reported in cases of NKH-related seizures present in the literature, even as an isolated imaging finding without cortical involvement. [6][7][8][9][10][11][12][13][14][15][16][17][21][22][23][24][25][26] These findings are usually unilateral and focal, involving mainly parieto-occipital and perirolandic regions, and show a good correlation with the EEG focus. Previous case reports and small series reporting the presence of MRI abnormalities in a total of 51 patients with NKH-related seizures are listed in Table 2.…”

Unusual magnetic resonance imaging abnormality in nonketotic hyperglycemia – related epilepsia partialis continua

“…[ 6 7 ] The leptomeningeal enhancement is an unusual manifestation in hyperglycemic state but has been reported in cases with hyperglycemia-related seizures. [ 4 8 ] The associated differential diagnosis of leptomeningeal enhancement with subcortical T2 hypointensity includes focal patchy meningitis, encephalitis, hemorrhagic infarcts, malignancy, and paraneoplastic process. [ 6 ] Almost these etiologies can be excluded in our case on the basis of patient's history and clinical manifestations with a shortly reversible clinical course and MRI abnormalities.…”