Diffusion MR imaging of hypoglycemic encephalopathy

Abnormal movements in critical care patients with brain injury: a diagnostic approach

Abnormal movements are frequently encountered in patients with brain injury hospitalized in intensive care units (ICUs), yet characterization of these movements and their underlying pathophysiology is difficult due to the comatose or uncooperative state of the patient. In addition, the available diagnostic approaches are largely derived from outpatients with neurodegenerative or developmental disorders frequently encountered in the outpatient setting, thereby limiting the applicability to inpatients with acute brain injuries. Thus, we reviewed the available literature regarding abnormal movements encountered in acutely ill patients with brain injuries. We classified the brain injury into the following categories: anoxic, vascular, infectious, inflammatory, traumatic, toxic-metabolic, tumor-related and seizures. Then, we identified the abnormal movements seen in each category as well as their epidemiologic, semiologic and clinicopathologic correlates. We propose a practical paradigm that can be applied at the bedside for diagnosing abnormal movements in the ICU. This model seeks to classify observed abnormal movements in light of various patient-specific factors. It begins with classifying the patient’s level of consciousness. Then, it integrates the frequency and type of each movement with the availability of ancillary diagnostic tests and the specific etiology of brain injury.

Brain glucose metabolism during hypoglycemia in type 1 diabetes: insights from functional and metabolic neuroimaging studies

Hypoglycemia is the most frequent complication of insulin therapy in patients with type 1 diabetes. Since the brain is reliant on circulating glucose as its main source of energy, hypoglycemia poses a threat for normal brain function. Paradoxically, although hypoglycemia commonly induces immediate decline in cognitive function, long-lasting changes in brain structure and cognitive function are uncommon in patients with type 1 diabetes. In fact, recurrent hypoglycemia initiates a process of habituation that suppresses hormonal responses to and impairs awareness of subsequent hypoglycemia, which has been attributed to adaptations in the brain. These observations sparked great scientific interest into the brain's handling of glucose during (recurrent) hypoglycemia. Various neuroimaging techniques have been employed to study brain (glucose) metabolism, including PET, fMRI, MRS and ASL. This review discusses what is currently known about cerebral metabolism during hypoglycemia, and how findings obtained by functional and metabolic neuroimaging techniques contributed to this knowledge.

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.

Reversible splenium diffusion weighted MRI changes associated with hypoglycemia

Hypoglycemia can manifest as a stroke. MRI diffusion-weighted imaging is the most useful technique in diagnosing early ischemic injury. We report two cases of transient MRI lesions of the splenium of the corpus callosum related to hypoglycemia. Clinicians must be aware of such cases to avoid misdiagnosis.

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.

Magnetic resonance imaging characteristics of persistent vegetative state due to prolonged hypoglycemia

Hypoglycemia is the sudden decrease in serum glucose level <50mg/dL. Neurological manifestations complicating profound and prolonged hypoglycemia range from reversible focal deficits and transient encephalopathy to irreversible coma. Here, we report magnetic resonance imaging characteristics of a patient with prolonged hypoglylicemia. A 47-year-old woman with a history of insulin dependent diabetes mellitus has been brought to the emergency room by her relatives. She used mistakenly overdose insulin injection and probably stayed 11 hours with low level blood glucose. The initial blood sugar level was 39.6 mg/dL at the emergency department visit, which was recovered urgently by 50% dextrose. MR imaging revealed high intensities at the bilateral posterior parietal cortices, corona radiata and hippocampus, but not in the basal ganglia. Seventy-two hour after admission, confluent lesions in the posterior parietal, temporal, frontal cortices and splenium of corpus callosum were more prominent on DWI and FLAIR, and did not match typical arterial territories. None of the lesions were enhanced on contrast-enhanced T1-weighted images. The prognosis or neurologic sequelae of hypoglycemic encephalopathy may depend on the severity and duration of hypoglycemia and persistent, diffuse involvement of the cerebral cortex, basal ganglia, or hippocampus on the following MR imaging. MR imaging findings in hypoglycemic vegetative state can be helpful in the differential diagnosis distinguishing from other neurologic conditions.

Effect of hypoglycemia on brain structure in people with type 2 diabetes: epidemiological analysis of the ACCORD-MIND MRI trial

OBJECTIVE

The effect of hypoglycemia related to treatment of type 2 diabetes mellitus (T2DM) on brain structure remains unclear. We aimed to assess whether symptomatic severe hypoglycemia is associated with brain atrophy and/or white matter abnormalities.

RESEARCH DESIGN AND METHODS

We included T2DM participants with brain MRI from the Action to Control Cardiovascular Risk in Diabetes-Memory in Diabetes (ACCORD-MIND) trial. Symptomatic severe hypoglycemia was defined as blood glucose <2.8 mmol/L or symptoms resolved with treatments that required the assistance of another person or medical assistance (hypoglycemia requiring assistance [HA]). Standardized brain MRI was performed at baseline and at 40 months. Total brain volume (TBV) and abnormal white matter (AWM) volume were calculated using an automated computer algorithm. Brain MRI scans of hypoglycemic participants were also reviewed for local disease.

RESULTS

Of the 503 T2DM participants (mean age, 62 years) with successful baseline and 40-month brain MRI, 28 had at least one HA episode during the 40-month follow-up. Compared with participants without HA, those with HA had marginally significant less atrophy (less decrease in TBV) from baseline to 40 months (-9.55 [95% CI -15.21, -3.90] vs. -15.38 [95% CI -16.64, -14.12], P = 0.051), and no significant increase of AWM volume (2.06 [95% CI 1.71, 2.49] vs. 1.84 [95% CI 1.76, 1.91], P = 0.247). In addition, no unexpected local signal changes or volume loss were seen on hypoglycemic participants' brain MRI scans.

CONCLUSIONS

Our study suggests that hypoglycemia related to T2DM treatment may not accentuate brain pathology, specifically brain atrophy or white matter abnormalities.

Neuroimaging correlates of acute encephalopathy

Acute encephalopathies arise as a result of various contributions from infections or toxic, metabolic, and/or structural cerebral derangements. With the variety of clinical presentations, neurologic examination, electroencephalography (EEG), and imaging may not identify specific etiologies, but in combination, they can offer guidance regarding underlying causes. Among several different neuroimaging techniques, cerebral computed tomography and brain magnetic resonance imaging are most frequently used for diagnosis, treatment monitoring, and prognostication in acute brain dysfunction. This review compiles the most common and typical features of head computed tomography and magnetic resonance imaging and presents the clinical and EEG associations in adult patients with different types of acute encephalopathy.

Acute encephalopathy with unilateral cortical-subcortical lesions in two unrelated kindreds treated with glucocorticoids prenatally for congenital adrenal hyperplasia due to 21-hydroxylase deficiency: established facts and novel insight

BACKGROUND

Prenatal glucocorticoid (GC) treatment of the female fetus with 21-hydroxylase deficiency (21-OHD) may prevent genital virilization and androgen effects on the brain, but prenatal GC therapy is controversial because of possible adverse effects on fetal programming, the cardiovascular system and the brain.

CASE REPORTS

We report 2 patients with congenital adrenal hyperplasia (CAH) due to 21-OHD who were treated prenatally with dexamethasone, suffered from an acute encephalopathy and showed focal and multifocal cortical and subcortical diffusion restrictions in early MRI and signs of permanent alterations in the follow-up neuroimaging studies. Both patients recovered from the acute episode. Whereas the first patient recovered without neurological sequelae the second patient showed hemianopsia and spastic hemiplegia in the neurological follow-up examination.

CONCLUSION

These are 2 children with CAH, both treated prenatally with high doses of dexamethasone to prevent virilization. The question arises whether prenatal high-dose GC treatment in patients with CAH might represent a risk factor for brain lesions in later life. Adverse effects/events should be reported systematically in patients undergoing prenatal GC treatment and long-term follow-up studies involving risk factors for cerebrovascular disease should be performed.

Neurologic damage in hypoglycemia

Hypoglycemia occurs in diabetic patients as a consequence of treatment with hypoglycemic agents, in insulinoma patients as a result of excessive insulin production, and in infants as a result of abnormal regulation of metabolism. Profound hypoglycemia can cause structural and functional disturbances in both the central (CNS) and the peripheral nervous system (PNS). The brain is damaged by a short and severe episode of hypoglycemia, whereas PNS pathology appears after a mild and prolonged episode. In the CNS, damaged mitochondria, elevated intracellular Ca2(+) level, released cytochrome c to the cytosol, extensive production of superoxide, increased caspase-3 activity, release of aspartate and glutamate from presynaptic terminals, and altered biosynthetic machinery can lead to neuronal cell death in the brain. Considering the PNS, chronic hypoglycemia is associated with delayed motor and sensory conduction velocities in peripheral nerves. With respect to pathology, hypoglycemic neuropathy in the PNS is characterized by Wallerian-like axonal degeneration that starts at the nerve terminal and progresses to a more proximal part of the axon, and motor axons to the muscles may be more severely damaged than sensory axons. Since excitatory neurotransmitters primarily involve the neuron in the CNS, this "dying back" pattern of axonal damage in the PNS may involve mechanisms other than excitotoxicity.

Actinomyces meyeri meningitis: the need for anaerobic cerebrospinal fluid cultures

We herein present a rare case of Actinomyces meyeri-induced meningitis that occurred in a patient of advanced age with poor oral hygiene. Although Gram staining of the cerebrospinal fluid (CSF) revealed Gram-positive rods and a blood culture was positive for the organism, a bacterial culture of the CSF was negative. Anaerobic cultures of CSF specimens are not routinely performed; however, anaerobes are sometimes involved in central nervous system infection. We therefore believe that anaerobic cultures should be considered in high-risk cases, such as those involving necrotizing bowel lesions or poor oral hygiene. A negative result on a CSF culture can result in misdiagnosis and inappropriate treatment.

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.

Continuous octreotide infusion for sulfonylurea-induced hypoglycemia in a toddler

BACKGROUND

Ingestion of a sulfonylurea by toddlers can cause profound hypoglycemia and neurologic sequelae. Although mild cases can be managed with dextrose and boluses of octreotide, optimal management of patients with severe hypoglycemia and cerebral injury has not been well established.

OBJECTIVE

Our objective was to report the use of continuous infusion octreotide for tight glucose control after accidental sulfonylurea ingestion with severe neurologic dysfunction.

CASE REPORT

A 17-month-old child presented to the emergency department with marked hypoglycemia, cerebral edema, and persistent seizures after ingestion of an unknown amount of glipizide. Hypoglycemia was refractory to i.v. dextrose bolus/infusion and subcutaneous octreotide. Continuous i.v. octreotide was utilized in conjunction with low-volume/high-concentration dextrose infusion as treatment, allowing for tight glucose and fluid management in the setting of cerebral edema.

CONCLUSIONS

Continuous infusion of octreotide resulted in rapid stabilization of blood glucose levels while maintaining fluid-restriction goals. Our patient demonstrated reversibility of diffuse cerebral edema in this setting with near complete recovery of neurologic function. Octreotide administration by continuous infusion may be preferable to subcutaneous bolus administration for the treatment of severe sulfonylurea-induced hypoglycemia with associated neurologic injury.

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.

Imaging of prion diseases

Prion diseases are caused by self-replicating proteins that induce lethal neurodegenerative disorders. In the last decade, the understanding of the different clinical, pathological, and neuroimaging phenotypes of this group of disorders has evolved paralleling the advances in prion molecular biology. From an imaging standpoint, the implementation of diffusion-weighted imaging in routine practice has markedly facilitated the detection of prion diseases, especially Creutzfeldt-Jakob. Less frequent prion-related disorders, including genetic diseases, may also benefit from progresses in the field of quantitative diffusion-weighted imaging, MR spectroscopy or molecular imaging. Herein, we present a review of the neuroimaging features of the prion disorders known to affect humans emphasizing the important contribution of MRI in the diagnosis of this group of disorders.

Profound hypoglycemia presents with reversible symmetrical ADC signal changes isolated to eloquent cortex of the parietal lobe

MRI diffusion/ADC signal change with reversal, symmetrically isolated to the cortex of the precentral gyri in profound hypoglycemia has not been previously described. We present a case in which minimal cortical signal change without deep gray matter involvement and subsequent reversal occurred without significant clinical improvement. Correlation of the reversal of diffusion/ADC signal to findings by EEG evaluation has been described in animal studies and not in humans before.

Hypoglycemic encephalopathy: a case series and literature review on outcome determination

Data on clinical long-term outcome after the acute phase of hypoglycemic encephalopathy (HE) using validated outcome scales is currently unavailable. Here we report the results of a systematic literature search for studies on HE and data on long-term outcome in patients with HE admitted to three Charité hospitals between January 2005 and July 2010. HE was defined as coma/stupor and blood glucose levels <50 mg/dl on admission, persistence of coma/stupor for ≥24 h despite normalization of blood glucose levels, and exclusion of any other cause of coma/stupor. Outcome was assessed using the modified Rankin scale (mRS), Glasgow Outcome Scale (GOS), and Barthel index (BI). Fifteen patients were included, with a mean age of 60 years (range 29-79). Two were lost to follow-up. Of the remaining 13 patients, six had died (46 %). In the seven survivors, the median mRS score was 0 (range 0-5), median GOS score was 5 (range 2-5), and median BI was 100 (range 0-100). MRIs made in the acute phase were available for three patients and revealed no obvious relation between lesion size or pattern and clinical outcome. To our knowledge, this is the first case series using validated clinical scoring systems to determine clinical long-term outcome after HE. The results suggest that mortality is high, but long-term survival with little or no disability is possible and can be observed in the majority of survivors. Risk of death or poor outcome does not seem to be related to MRI features in the acute phase but rather to other presumably medical factors.

Metabolic encephalopathies

Kinnier Wilson coined the term metabolic encephalopathy to describe a clinical state of global cerebral dysfunction induced by systemic stress that can vary in clinical presentation from mild executive dysfunction to deep coma with decerebrate posturing; the causes are numerous. Some mechanisms by which cerebral dysfunction occurs in metabolic encephalopathies include focal or global cerebral edema, alterations in transmitter function, the accumulation of uncleared toxic metabolites, postcapillary venule vasogenic edema, and energy failure. This article focuses on common causes of metabolic encephalopathy, and reviews common causes, clinical presentations and, where relevant, management.

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

BACKGROUND AND PURPOSE

The relationship between the MR imaging features and clinical outcomes in patients with hypoglycemic encephalopathy has always been evaluated retrospectively. The aim of this study was to prospectively evaluate whether MR imaging features of patients presenting with hypoglycemic coma are predictive of short-term (1-week) outcomes.

MATERIALS AND METHODS

Subjects were 36 consecutive patients with hypoglycemia who were in a comatose state on arrival at our hospital from April 2006 to March 2010. MR imaging findings on arrival in relation to the patients' clinical course after glucose infusion were evaluated.

RESULTS

Thirteen of the 36 patients showed no MR imaging abnormalities on arrival. DWI revealed focal lesions involving the internal capsule in 13 patients and lesions involving bilateral hemispheric white matter in 10 patients. After glucose administration, the patients without lesions and patients with focal internal capsule lesions recovered completely within 1 day. However, patients with diffuse white matter lesions did not recover even within 1 week despite glucose administration. There was no statistical difference in the initial blood glucose levels among patients with the various types of MR imaging findings.

CONCLUSIONS

On early MR imaging, hypoglycemic brain injury may first appear in the internal capsule and then spread into the hemispheric white matter. The absence of a lesion or the presence of a focal internal capsule lesion may suggest a good outcome. However, diffuse hemispheric white matter lesions may indicate a poor 1-week outcome.

Diffusion-weighted imaging for the differential diagnosis of disorders affecting the hippocampus

BACKGROUND

The human hippocampus can be affected in a large variety of very different neurological diseases, of which acute ischemic stroke, transient global amnesia, epilepsy, and limbic encephalitis are the most common. Less frequent etiologies include various infections and encephalopathy of different origins. Clinical presentation notably comprises confusional state, altered vigilance, memory deficits of various extent and seizures. While in hypoxic or hypoglycemic encephalopathy, clinical presentation and surrounding circumstances provide some clues to reach the correct diagnosis, in the above-listed more common disorders, signs and symptoms might overlap, making the differential diagnosis difficult. This review presents recent studies using the diffusion-weighted imaging (DWI) technique in diseases involving the hippocampus.

METHODS

References for the review were identified through searches of PubMed from 1965 to January 2011. Only papers published in English were reviewed. Full articles were obtained and references were checked for additional material where appropriate.

RESULTS

All pathologies affecting the hippocampus are associated with distinct lesion patterns on magnetic resonance imaging, and especially DWI has the ability to demonstrate even minute and transient hippocampal lesions. In acute ischemic stroke in the posterior cerebral artery territory, involvement of the hippocampal formation occurs in four distinct patterns on DWI that can be easily differentiated and correspond to the known vascular anatomy of the hippocampus. In the subacute phase after transient global amnesia (TGA), dot-like hyperintense lesions are regularly found in the lateral aspect of the hippocampus on DWI. The DWI lesions described after prolonged seizures or status epilepticus include unilateral or bilateral hippocampal, thalamic, and cortical lesions of various extent, not restricted to vascular territories. In limbic encephalitis, DWI lesions are only infrequently found and usually affect the hippocampus, uncus and amygdala. Furthermore, in some rare cases DWI lesions of different etiology may coexist.

CONCLUSION

In patients with diseases affecting the hippocampus, DWI appears to be useful in differentiating between underlying pathologies and may facilitate a definite diagnosis conducive to an optimal treatment. With a careful clinical examination, experience with the interpretation of DWI findings and knowledge of associated phenomena, it is indeed possible to differentiate between ischemic, ictal, metabolic, and TGA-associated findings.

Serum calcium concentration affects signal changes on diffusion-weighted imaging in hypoglycemic encephalopathy

BACKGROUND AND PURPOSE

Abnormal signals in brain DWI may appear in patients with HE. The aim of this study was to compare the clinical condition and various physiologic factors between patients with HE with and without abnormal signal intensity changes on DWI.

MATERIALS AND METHODS

We retrospectively enrolled patients with HE who underwent brain DWI studies from January 2002 to November 2010. A diagnosis of HE was defined as low serum glucose levels (<50 mg/dL) with alteration of consciousness. Several clinical conditions and physiologic parameters were compared between patients with and without abnormal signals on DWI, including consciousness levels; outcome; body temperature; blood pressure; and serum levels of glucose, calcium, sodium, blood urea nitrogen, and creatinine.

RESULTS

Nine patients with HE were included, and 3 of them (33%) had abnormal signals on brain DWI. There was a trend toward serum calcium concentrations being lower in patients with normal findings on DWI studies compared with patients with abnormal DWI signals (7.6 ± 1.7 versus 9.4 ± 0.7 mg/dL, P = .07). Serum glucose concentration, duration of hypoglycemia, consciousness levels, other physiologic parameters, and clinical outcome did not reveal any differences between the 2 groups.

CONCLUSIONS

One-third of patients with HE had abnormal signals on brain DWI, and patients with low serum calcium levels may be less likely to present with abnormal DWI signals.