Early diffusion MR imaging findings and short-term outcome in comatose patients with hypoglycemia

Hypoglycemic encephalopathy with extensive brain injuries: A case report

Hypoglycemia is known as a sudden diminution in blood glucose level <50 mg/dL. Hypoglycemic encephalopathy is a metabolic encephalopathy that is usually observed in patients treated for diabetes or chronic alcoholism. Neurological manifestations may range from transient deficits to prolonged coma, depending on the duration and severity of hypoglycemia. Neuroradiological features of hypoglycemia are variable involving the cerebral white and gray matter regions. Acquired metabolic or toxic conditions can cause hypoglycemia-like damage to the cerebral white matter and basal ganglia. Widespread lesions in the brain parenchyma or basal ganglia have a poor prognosis. In this report, we present a patient with widespread brain damage secondary to profound and prolonged hypoglycemia.

Bilateral middle cerebellar peduncle compromise due to hypoglycemic encephalopathy: A case report and literature review

Hypoglycemic encephalopathy constitutes a critical presentation of severely diminished glucose levels. We present the case of a 53-year-old male patient with a history of diabetes mellitus with hypoglycemic encephalopathy and MRI findings of bilateral middle cerebellar peduncle lesions. Common findings of hypoglycemic encephalopathy described in the literature consist of bilateral compromise of the cerebral cortex, basal ganglia, hippocampus, and long tracts of white matter. The cerebellum and brainstem are usually not affected. This is the ninth report of cerebellar peduncle compromise with hypoglycemia. As increasing evidence regarding prognosis estimation of lesion distribution arises, we consider it important to report the different cases of rare patterns of compromise.

Dynamic magnetic resonance imaging findings in the early stages of neonatal hypoglycemic brain injury

Hypoglycemia is common among neonates and can cause neurological dysfunction. This study aimed to identify the specific time window to perform diffusion-weighted imaging (DWI) for detecting early brain injury in neonatal hypoglycemia and assess the clinical characteristics and neurological outcomes of different patterns of brain injury in neonatal hypoglycemia. We conducted a retrospective analysis of the changes in conventional magnetic resonance imaging (MRI) and DWI at different time points and clinical characteristics in 86 neonates with hypoglycemic brain injury. Among 139 DWI scans, 84 showed injury site hyperintensities within 7 days after hypoglycemia. Thirty-nine scans revealed low DWI and abnormal T1-/T2-weighted imaging signals within 11-23 days after onset, of which 21 showed DWI hyperintensities in the corpus callosum. Abnormal signals were undetected in the second scans of 13 infants within 9-20 days after onset. Vulnerable sites comprised the occipital lobe (98%), splenium of the corpus callosum (60%), and parietal lobe (30%). Compared with focal injury (n = 66), extensive injury (n = 20) had higher involvement of the internal capsule, basal ganglia, and thalamus (P < 0.05); higher incidence of recurrent convulsions, respiratory failure, and coma (P < 0.01); and a higher proportion of death and severe neurodevelopmental impairment (P < 0.05).

CONCLUSIONS

Neonatal hypoglycemic brain injury was most common in the occipital lobes. Severe clinical symptoms were significantly associated with extensive brain injury involving the internal capsule, basal ganglia, and thalamus, which could be attributed to hypoxia-ischemia and lead to a poor prognosis.

WHAT IS KNOWN

• There is no clear neurological safe threshold for hypoglycemia in neonates. Studies suggest that symptomatic hypoglycemia can be related to brain injury.

WHAT IS NEW

• Severe clinical symptoms are significantly associated with extensive brain injury on MRI scans. Extensive brain injuries involving the internal capsule, basal ganglia, and thalamus, which could be due to associated hypoxia-ischemia and lead to a poor prognosis.

Description and Outcome of Severe Hypoglycemic Encephalopathy in the Intensive Care Unit

BACKGROUND

Disorders of consciousness due to severe hypoglycemia are rare but challenging to treat. The aim of this retrospective cohort study was to describe our multimodal neurological assessment of patients with hypoglycemic encephalopathy hospitalized in the intensive care unit and their neurological outcomes.

METHODS

Consecutive patients with disorders of consciousness related to hypoglycemia admitted for neuroprognostication from 2010 to 2020 were included. Multimodal neurological assessment included electroencephalography, somatosensory and cognitive event-related potentials, and morphological and quantitative magnetic resonance imaging (MRI) with quantification of fractional anisotropy. Neurological outcomes at 28 days, 3 months, 6 months, 1 year, and 2 years after hypoglycemia were retrieved.

RESULTS

Twenty patients were included. After 2 years, 75% of patients had died, 5% remained in a permanent vegetative state, 10% were in a minimally conscious state, and 10% were conscious but with severe disabilities (Glasgow Outcome Scale-Extended scores 3 and 4). All patients showed pathologic electroencephalography findings with heterogenous patterns. Morphological brain MRI revealed abnormalities in 95% of patients, with various localizations including cortical atrophy in 65% of patients. When performed, quantitative MRI showed decreased fractional anisotropy affecting widespread white matter tracts in all patients.

CONCLUSIONS

The overall prognosis of patients with severe hypoglycemic encephalopathy was poor, with only a small fraction of patients who slowly improved after intensive care unit discharge. Of note, patients who did not improve during the first 6 months did not recover consciousness. This study suggests that a multimodal approach capitalizing on advanced brain imaging and bedside electrophysiology techniques could improve diagnostic and prognostic performance in severe hypoglycemic encephalopathy.

Neurological Prognostication After Hypoglycemic Coma: Role of Clinical and EEG Findings

BACKGROUND

Hypoglycemic coma (HC) is an uncommon but severe clinical condition associated with poor neurological outcome. There is a dearth of robust neurological prognostic factors after HC. On the other hand, there is an increasing body of literature on reliable prognostic markers in the postanoxic coma, a similar-albeit not identical-situation. The objective of this study was thus to investigate the use and predictive value of these markers in HC.

METHODS

We conducted a retrospective, multicenter, cohort study within five centers of the Critical Care EEG Monitoring Research Consortium. We queried our electroencephalography (EEG) databases to identify all patients undergoing continuous EEG monitoring after admission to an intensive care unit with HC (defined as Glasgow Coma Scale < 8 on admission and a first blood glucose level < 50 mg/dL or not documented but in an obvious clinical context) between 01/01/2010 and 12/31/2020. We studied the association of findings at neurological examination (Glasgow Coma Scale motor subscale, pupillary light and corneal reflexes) and at continuous EEG monitoring(highly malignant patterns, reactivity, periodic discharges, seizures) with best neurological outcome within 3 months after hospital discharge, defined by the Cerebral Performance Category as favorable (1-3: recovery of consciousness) versus unfavorable (4-5: lack of recovery of consciousness).

RESULTS

We identified 60 patients (30 [50%] women; age 62 [51-72] years). Thirty-one and 29 patients had a favorable and unfavorable outcome, respectively. The presence of pupillary reflexes (24 [100%] vs. 17 [81%]; p value 0.04) and a motor subscore > 2 (22 [92%] vs. 12 [63%]; p value 0.03) at 48-72 h were associated with a favorable outcome. A highly malignant EEG pattern was observed in 7 of 29 (24%) patients with unfavorable outcome versus 0 of 31 (0%) with favorable outcome, whereas the presence of EEG reactivity was observed in 28 of 31 (90%) patients with favorable outcome versus 13 of 29 (45%) with unfavorable outcome (p < 0.001 for comparison of all background categories).

CONCLUSIONS

This preliminary study suggests that highly malignant EEG patterns might be reliable prognostic markers of unfavorable outcome after HC. Other EEG findings, including lack of EEG reactivity and seizures and clinical findings appear less accurate. These findings should be replicated in a larger multicenter prospective study.

Predictors of consciousness improvement in patients with hypoglycemic encephalopathy

AIMS

Hypoglycemic encephalopathy (HE) can cause long-lasting mental changes, disability, and even death. We aimed to investigate prognostic factors for HE and to determine when the treatment of HE becomes futile.

METHODS

We retrospectively evaluated the data of patients admitted for prolonged HE at Dongguk University Ilsan Hospital between December 2005 and July 2021. We assessed the Glasgow Outcome Scale (GOS) to assess functional outcome.

RESULTS

Forty-four patients were enrolled in the study. Thirty-two of these showed the improvement on GOS after treatment. Patients with improved consciousness had a shorter duration of hypoglycemia (1.6±1.4 vs. 7.8±15.0 hours, p = 0.04) and a lower incidence of brain lesions than those without improvements in consciousness (76.0% vs. 25.0%, p < 0.01). Patients whose lesions were detected in initial MRIs were 1.3 times less likely to recover consciousness after HE (odds ratios, 1.28; 95% CI, 1.09-1.52; p < 0.01). None of the patients recovered consciousness after 320 h. Maximum time spent to recover was 194 in patients without brain lesions and 319 in those with lesions.

CONCLUSIONS

Hypoglycemic brain injury detected in initial MRIs predicted poorer HE prognosis. Nevertheless, treatment should be provided for at least for 14 days after admission.

Clinical applications of diffusion-weighted sequence in brain imaging: beyond stroke

Diffusion-weighted imaging (DWI) is a well-established MRI sequence for diagnosing early stroke and provides therapeutic implications. However, DWI yields pertinent information in various other brain pathologies and helps establish a specific diagnosis and management of other central nervous system disorders. Some of these conditions can present with acute changes in neurological status and mimic stroke. This review will focus briefly on diffusion imaging techniques, followed by a more comprehensive description of the utility of DWI in common neurological entities beyond stroke.

Acute Acquired Metabolic Encephalopathy Based on Diffusion MRI

Metabolic encephalopathy is a critical condition that can be challenging to diagnose. Imaging provides early clues to confirm clinical suspicions and plays an important role in the diagnosis, assessment of the response to therapy, and prognosis prediction. Diffusion-weighted imaging is a sensitive technique used to evaluate metabolic encephalopathy at an early stage. Metabolic encephalopathies often involve the deep regions of the gray matter because they have high energy requirements and are susceptible to metabolic disturbances. Understanding the imaging patterns of various metabolic encephalopathies can help narrow the differential diagnosis and improve the prognosis of patients by initiating proper treatment regimen early.

Suspecting unwitnessed hypoglycaemia

Hypoglycaemic coma can present with acute neurological dysfunction mimicking stroke. It may be masked by normoglycaemia due to physiological compensatory mechanisms (Somogyi phenomenon). Specific MR brain scan changes should alert the clinician to consider this alternative to stroke in the acute setting in patients with a history of recurrent hypoglycaemia, even when the blood glucose is not low at presentation. Rapid identification and treatment of hypoglycaemia may confer a good prognosis with radiological resolution.

Histopathological and immunohistochemical analysis of the cerebral white matter after transient hypoglycemia in rat

Patients with hypoglycemic coma show abnormal signals in the white matter on magnetic resonance imaging. However, the precise pathological changes in the white matter caused by hypoglycemic coma remain unclear in humans and experimental animals. This study aimed to reveal the distribution and time course of histopathological and immunohistochemical changes occurring in the white matter during the early stages of hypoglycemic coma in rats. Insulin-induced hypoglycemic coma of 15–30-min duration was induced in rats, followed by recovery using a glucose solution. Rat brains were collected after 6 and 24 hr and after 3, 5, 7, and 14 days. The brains were submitted for histological and immunohistochemical analysis for neurofilament 200 kDa (NF), myelin basic protein, olig-2, Iba-1, and glial fibrillary acidic protein (GFAP). Vacuolation was observed in the fiber bundles of the globus pallidus on days 1–14. Most of the vacuoles were located in GFAP-positive astrocytic processes or the extracellular space and appeared to be edematous. Additionally, myelin pallor and a decrease in NF-positive signals were observed on day 14. Microgliosis and astrogliosis were also detected. Observations similar to the globus pallidus, except for edema, were noted in the internal capsule. In the corpus callosum, a mild decrease in NF-positive signals, microgliosis, and astrogliosis were observed. These results suggest that after transient hypoglycemic coma, edema and/or degeneration occurred in the white matter, especially in the globus pallidus, internal capsule, and corpus callosum in the early stages.

A multimodal approach using somatosensory evoked potentials for prognostication in hypoglycemic encephalopathy

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Hypoglycemic encephalopathy may be associated with poor neurological prognosis.

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Little data exists to guide prognostication in hypoglycemic encephalopathy.

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We describe a multimodal approach to prognostication in hypoglycemia.

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MRI, EEG, and SSEPs estimate severity of brain injury in hypoglycemic coma.

Objectives

We present a case of a patient with hypoglycemic encephalopathy with loss of median nerve N20 somatosensory evoked potentials (SSEPs) and describe our multimodal approach to prognostication in hypoglycemic encephalopathy.

Case

The patient was a 67-year-old woman with type 2 diabetes and stage 5 chronic kidney disease hospitalized for hypoglycemic encephalopathy. SSEPs showed bilateral absence of the median nerve N20 response. She ultimately suffered a poor outcome.

Discussion

There are no high-quality evidence-based clinical, neurophysiologic, or imaging studies available to aid in neurologic outcome prediction in hypoglycemic encephalopathy. In our practice we use a multimodal approach to neurologic prognostication, similar to that used in coma after cardiac arrest that includes SSEPs, EEG, and brain MRI, which enables an estimate of the severity of brain injury. As the literature is largely based on small studies or case reports, and is extrapolated from the cardiac arrest literature, we caution against early prognostication and disposition including the withdrawal of care, to avoid a self-fulfilling prophecy.

Risk Factors of Hypoglycemic Encephalopathy and Prolonged Hypoglycemia in Patients With Severe Hypoglycemia

Background

The aim of the study was to investigate risk factors of hypoglycemic encephalopathy (HE) in patients with severe hypoglycemia.

Methods

We retrospectively enrolled patients with severe hypoglycemia who were transported to the emergency department in an ambulance. We defined severe hypoglycemia as plasma glucose level < 60 mg/dL (or capillary levels < 50 mg/dL). HE was defined as severe hypoglycemia with altered level of consciousness (Glasgow coma scale < 12) and prolonged HE as coma or stupor lasting > 24 h after glucose administration. We compared several parameters between patients with and without HE and between prolonged and recovered patients.

Results

Included were 173 patients with severe hypoglycemia; of them, 94 were diagnosed with HE, with 12 of them prolonged HE. Glucose level in HE patients was lower than that in those without HE (P < 0.001). Moreover, we noted a significant difference in glucose levels between the prolonged and recovered groups. Furthermore, body temperature was higher in prolonged versus recovered patients (P = 0.0017).

Conclusion

Blood glucose level may be correlated with severity of altered level of consciousness. In addition, body temperature may be related to coma or prolonged stupor.

Hypothermic neuroprotection during reperfusion following exposure to aglycemia in central white matter is mediated by acidification

Hypoglycemia is a common iatrogenic consequence of type 1 diabetes therapy that can lead to central nervous system injury and even death if untreated. In the absence of clinically effective neuroprotective drugs we sought to quantify the putative neuroprotective effects of imposing hypothermia during the reperfusion phase following aglycemic exposure to central white matter. Mouse optic nerves (MONs), central white matter tracts, were superfused with oxygenated artificial cerebrospinal fluid (aCSF) containing 10 mmol/L glucose at 37°C. The supramaximal compound action potential (CAP) was evoked and axon conduction was assessed as the CAP area. Extracellular lactate was measured using an enzyme biosensor. Exposure to aglycemia, simulated by omitting glucose from the aCSF, resulted in axon injury, quantified by electrophysiological recordings, electron microscopic analysis confirming axon damage, the extent of which was determined by the duration of aglycemia exposure. Hypothermia attenuated injury. Exposing MONs to hypothermia during reperfusion resulted in improved CAP recovery compared with control recovery measured at 37°C, an effect attenuated in alkaline aCSF. Hypothermia decreases pH implying that the hypothermic neuroprotection derives from interstitial acidification. These results have important clinical implications demonstrating that hypothermic intervention during reperfusion can improve recovery in central white matter following aglycemia.

Agraphia with reversible splenial corpus callosum lesion caused by hypoglycemia

BACKGROUND

Neurological manifestations caused by hypoglycemia range from reversible focal deficits and transient encephalopathy to irreversible coma or death. Recently, high signal intensity lesions in the splenium of the corpus callosum on diffusion-weighted magnetic resonance imaging were reported in adults experiencing hypoglycemia. However, patients presenting with agraphia are rare.

SUBJECT AND METHODS

We examined a 17-year-old left-handed female patient with type 1 diabetes who exhibited transient left agraphia with a reversible splenium lesion of the corpus callosum on diffusion-weighted imaging caused by hypoglycemia, which was improved with blood glucose management alone.

CONCLUSION

This rare case indicates that agraphia, a sign of callosal disconnection syndrome, can result from a reversible splenial lesion of the corpus callosum caused by hypoglycemia.

Severe Hypoglycemia-induced Right Hemiparesis with Reversible Diffusion Restriction in the Left Internal Capsule Due to Combination Therapy Using Disopyramide and Clarithromycin

Severe hypoglycemia is known to cause acute focal neurological symptoms. In cases with a medical history of diabetes mellitus (DM), the diagnosis and treatment of hypoglycemia-induced neurological symptoms are simple. However, severe hypoglycemia can occur in patients who are not taking hypoglycemic agents such as insulin or long-acting sulfonylurea drugs. We describe a 95-year-old man with sudden onset of right hemiparesis who showed high signal intensity on diffusion-weighted imaging involving the left internal capsule with corresponding reduced apparent diffusion coefficient hypointensity. Laboratory findings revealed severe hypoglycemia (27 mg/dl). However, he was not taking insulin or long-acting sulfonylurea drugs but disopyramide and clarithromycin had been administered. In addition, he had kidney dysfunction with an estimated glomerular filtration rate (GFR) of 42.9 ml/min/1.73 m². After the blood glucose level was normalized, the left hemiparesis completely recovered and abnormal findings of magnetic resonance imaging (MRI) study also became normal. A combination of disopyramide and clarithromycin may cause severe hypoglycemia-induced neurological symptoms particularly in patients with kidney dysfunction. Even in a patient with sudden-onset hemiparesis and no history of DM, the possibility of hypoglycemia-induced neurological deficit should be considered.

Beyond the embolus: "do not miss" diffusion abnormalities of ischaemic and non-ischaemic neurological disease

Abstract

Given the rapid evolution and technological advances in the diagnosis and treatment of acute ischaemic stroke (AIS), including the proliferation of comprehensive stroke centres and increasing emphasis on interventional stroke therapies, the need for prompt recognition of stroke due to acute large vessel occlusion has received significant attention in the recent literature. Diffusion-weighted imaging (DWI) is the gold standard for the diagnosis of acute ischaemic stroke, as images appear positive within minutes of ischaemic injury, and a high signal-to-noise ratio enables even punctate infarcts to be readily detected. DWI lesions resulting from a single arterial embolic occlusion or steno-occlusive lesion classically lateralise and conform to a specific arterial territory. When there is a central embolic source (e.g. left atrial thrombus), embolic infarcts are often found in multiple vascular territories. However, ischaemic disease arising from aetiologies other than arterial occlusion will often not conform to an arterial territory. Furthermore, there are several important entities unrelated to ischaemic disease that can present with abnormal DWI and which should not be confused with infarct. This pictorial review explores the scope and typical DWI findings of select neurologic conditions beyond acute arterial occlusion, which should not be missed or misinterpreted.

Teaching points

• DWI abnormalities due to acute arterial occlusion must be promptly identified.

• DWI abnormalities not due to arterial occlusion will often not conform to an arterial territory.

• Several important non-ischaemic entities can present on DWI and should not be confused with infarct.

Functional outcome of patients with prolonged hypoglycemic encephalopathy

Background

Little is known about the causes, clinical course and long-term outcome of comatose patients with prolonged hypoglycemic encephalopathy.

Methods

In a multicenter retrospective study conducted in patients hospitalized from July 1, 2004, to July 1, 2014, we investigated functional long-term prognosis and identified prognosis factors of patients admitted in an intensive care unit (ICU) with prolonged neurological manifestations related to hypoglycemia. Eligible patients were adults admitted to the ICU with a Glasgow Coma Score <8 due to hypoglycemia and persistent consciousness disorders after normalizing blood glucose levels. Patients with possible other causes of consciousness disorders, previous cognitive disorders, hypothermia <35 °C or circulatory arrest within 24 h after ICU admission, were excluded. Follow-up phone call was used to determine patients’ functional outcome using modified Rankin Scale (mRS) at a minimum of 1-year follow-up with mRS 0–3 defining good and mRS 4–6 poor outcomes.

Results

Forty-nine patients were included. Causes of hypoglycemia were various, mainly including insulin or oral antidiabetic drugs abuse (65%) and neuroendocrine carcinoma (16%). Twenty (41%) patients died in the ICU, two (4%) patients further died and nine (18%) patients had a poor outcome at long-term follow-up. Five patients discharged from the ICU with mRS > 3 improved enough to be in the good outcome group 1 year later. Twenty-two (45%) patients underwent therapeutic limitation, mainly related to no expected hope for improvement. On multivariate analysis, only low mRS prior to ICU admission (OR 2.6; 95% CI 1.1–6.3; P = 0.03) and normal brain imaging (OR 7.1; 95% CI 1.1–44; P = 0.03) were significantly predictive of a good outcome. All patients (n = 15) who remained hypoglycemic >480 min had a poor outcome.

Conclusion

Poor outcome was observed in about 60% of this population of hypoglycemic encephalopathy. However, some patients can recover satisfactorily over time.

Risk factors of severe hypoglycemia requiring medical assistance and neurological sequelae in patients with diabetes: A case-control study

Hypoglycemia commonly occurs in patients who are being treated for diabetes. In some cases, these patients suffer from severe hypoglycemia that requires medical assistance and which can unfortunately result in long-term disabilities. Therefore, we investigated risk factors associated with severe hypoglycemia requiring medical assistance (HMA) and the resulting neurological sequelae in patients with diabetes. This investigation was a case-control study that assessed 129 patients with diabetes and documented hypoglycemia from a single tertiary hospital between February 2013 and May 2015. They were treated with oral hypoglycemic agents alone (54%) or with insulin with/without oral hypoglycemic agents (46%). If a patient with diabetes visited the emergency department due to hypoglycemia, this was defined as HMA. The control group was composed of patients with documented, nonsevere hypoglycemia who visited the outpatient clinic during the same period. The degree of neurological disability in the HMA patients was measured using the modified Rankin Scale. A multivariate analysis revealed that independent risk factors of HMA were associated with a lack of the self-monitoring of blood glucose (SMBG) and previous episodes of severe hypoglycemia. In the HMA group, 15 patients (22%) had neurological sequelae at the time of discharge. Patients with neurological sequelae were older than those without sequelae (74.3 years vs 65.8 years, P = 0.006) and had increased psychological evidence of disorders such as insomnia, dementia, and depression (40% vs 11%, P = 0.017). Patients with sequelae were also more likely to live in rural areas (47% vs 19%, P = 0.04) and to have a longer time from last seen normal till glucose administration (5.2 hours vs 1.6 hours, P = 0.027). In the present study, absence of SMBG and previous severe hypoglycemic episodes were independent risk factors of HMA and patients with an older age, a psychological disorder, a rural residence, and a prolonged duration of hypoglycemia had higher risks of neurological sequelae. Therefore, the present findings suggest that physicians should aim to prevent hypoglycemia in patients with a history of hypoglycemia and provide education for these patients regarding regular SMBG.

Reversible Focal Splenial Lesion on Diffusion-Weighted MRI in Sulfonylurea Intoxication

Hypoglycemic brain injury is usually reversible, and partial recovery or mortality depends on the affected area. Diffusion-weighted imaging (DWI) may be useful in predicting the prognosis according to the site of involvement. Isolated lesions of the splenium of corpus callosum (SCC) in hypoglycemic brain injury are very rare, and DWI findings of a reversible lesion of the SCC due to deep hypoglycemia associated with sulfonylurea intoxication has been reported only once in the literature. We report the case of a 15-year-old girl admitted to the emergency department who had attempted suicide using sulfonylurea and subsequently went into a coma. The patient had no known previous disease. Except for a blood glucose level of 10 mg/dl, all other blood laboratory tests were normal. DWI performed two hours after admission showed diffusion restriction in the SCC. After receiving treatment for 24 hours, the patient became conscious, and her blood glucose level returned to normal. Two days later, complete resolution of the SCC lesion was revealed by control DWI. We discuss both the DWI findings of the reversible SCC lesion due to hypoglycemic brain injury resulting from sulfonylurea intoxication and the role of DWI in predicting the clinical outcome.

Hypoglycemia with focal neurological signs as stroke mimic: Clinical and neuroradiological characteristics

Our aim was to investigate the clinical and radiological features of patients with hypoglycemia with focal neurological signs (HFNS). Among 80 consecutive hypoglycemic patients (blood glucose levels less than 50mg/dL), who had been admitted between October 2008 and May 2012, we selected 11 patients (6 men and 5 women; mean age, 73.2 ± 12 years) with focal neurological signs. The mean initial blood glucose level was 27.9 mg/dL (range, 13-39 mg/dL). The most frequent symptom was unilateral motor weakness (n = 9), which was usually accompanied with mild or moderate alteration of consciousness. All patients had improved initial neurological signs within 1h of glucose injection. The initial DWI demonstrated a hyperintense lesion in the contralateral internal capsule with decreased values on the ADC (apparent diffusion coefficient) map in 2 of the patients (18%). The DWI performed one day later shows only faint lesion. The initial DWI in patients with HFNS may display a hyperintense lesion, which was difficult to distinguish from acute cerebral infarction. Hypoglycemia should be considered in cases with DWI showing a disproportionally small lesion in contrast to neurological signs.

MR screening of candidates for thrombolysis: How to identify stroke mimics?

Stroke mimics account for up to a third of suspected strokes. The main causes are epileptic deficit, migraine aura, hypoglycemia, and functional disorders. Accurate recognition of stroke mimics is important for adequate identification of candidates for thrombolysis. This decreases the number of unnecessary treatments and invasive vascular investigations. Correctly identifying the cause of symptoms also avoids delaying proper care. Therefore, this pictorial review focuses on what the radiologist should know about the most common MRI patterns of stroke mimics in the first hours after onset of symptoms. The issues linked to the accurate diagnosis of stroke mimics in the management of candidates for thrombolysis will be discussed.

Transient interhemispheric disconnection in a case of insulinoma-induced hypoglycemic encephalopathy

We report a case of a 22-year-old male who was transferred to our hospital in a comatose state following successive seizures. Low blood glucose had been detected upon his arrival at the previous hospital. He became responsive 12 days after the onset of coma. Upon regaining consciousness he exhibited severe dysarthria and several interhemispheric disconnection signs such as intermanual conflict, left-hand dysgraphia, left hemispatial neglect confined to the right hand, impaired interhemispheric transfer, and unilateral constructional apraxia of the right hand. Brain MRI disclosed T2-weighted and diffusion-weighted hyperintense lesions with reduced apparent diffusion coefficients in the bilateral centrum semiovale, splenium of the corpus callosum, right posterior limb of the internal capsule, and bilateral middle cerebellar peduncles. As the MRI findings vanished, his interhemispheric disconnection signs gradually resolved. Abdominal imaging studies revealed a pancreatic tumor, which was later endocrinologically diagnosed as an insulinoma. This is an extremely rare report of interhemispheric disconnection signs due to hypoglycemic encephalopathy. The lesions in the bilateral centrum semiovale likely contributed to the interhemispheric disconnection signs.

[A case of hypoglycemic coma with good outcome despite sustained unconsciousness and widespread leukoencephalopathy]

We described a 28-year-old woman with insulinoma-induced hypoglycemic coma. Her initial diffusion-weighted MRI revealed diffuse hyperintense lesions involving bilateral hemispheric white matter. She did not respond to the initial treatment with glucose. However, after surgical removal of insulinoma, she began to recover gradually, and 1 year later, returned to her previous work. In general, the outcome of hypoglycemic coma with widespread leukoencephalopathy on MRI is thought to be poor. However, we should be aware that some of such cases could recover in the long term.

Predictors of outcome in hypoglycemic encephalopathy

AIMS

The aim of this study was to investigate factors predicting poor prognosis in patients with hypoglycemic encephalopathy.

METHODS

We retrospectively analyzed data on 165 consecutive patients with hypoglycemic encephalopathy. We evaluated their outcome 1 week after hypoglycemia onset using the Glasgow outcome scale (GOS) and compared the clinical features of patients with good outcomes (GOS = 5) and poor outcomes (GOS ≤ 4).

RESULTS

The poor-outcome group included 38 patients (23%). The initial blood glucose level in the poor-outcome group was lower than that in the good-outcome group (p = 0.002). The duration of hypoglycemia in the poor-outcome group was longer than that in the good-outcome group (p < 0.001). Body temperature during hypoglycemia in the poor-outcome group was higher than that in the good-outcome group (p < 0.001). Furthermore, lactic acid level in the poor-outcome group was lower than in the good-outcome group (p = 0.032). There was no significant difference in the frequency of posttreatment hyperglycemia between the good-outcome and poor-outcome groups (p = 0.984).

CONCLUSION

Profound and prolonged hypoglycemia, normal or higher body temperature, and a low lactic acid level during hypoglycemia may be predictors of a poor outcome in patients with hypoglycemic encephalopathy.

Neuroimaging in patients with abnormal blood glucose levels

SUMMARY

Smooth neuronal functioning requires an uninterrupted supply of energy that is provided by glucose under normal physiologic conditions. Significant variations in plasma glucose levels, be it hypoglycemia or hyperglycemia, can present with myriad clinical manifestations and may mimic stroke. At times, the diagnosis is either not apparent or not clinically suspected. Imaging can suggest the diagnosis in unsuspected cases and can help in the assessment of the extent of neuronal damage in known cases, making it vital for the neuroradiologist to be aware of both common and atypical neuroimaging findings in hypoglycemia and hyperglycemia.

Diagnostic approach to restricted-diffusion patterns on MR imaging

The vast majority of restricted-diffusion abnormalities result from acute stroke, and as such, the diagnosis may be problematic when this MRI feature results from other causes. Distinct patterns of restricted diffusion seen with various disease conditions can play an important diagnostic role. The association of certain diseases with a given restricted-diffusion pattern allows for a focused assessment to determine a specific etiology.