Temporal Magnetic Resonance Imaging Changes in Acute Hypoglycemic Encephalopathy: Two Cases With Different Gray Matter Lesion Patterns

ABSTRACT

Early MRI in two patients with hypoglycemic encephalopathy revealed contrasting lesion distributions. Case 1 demonstrated widespread gray matter involvement, including the basal ganglia, with persistent coma. Case 2 exhibited patchy cortical lesions with neurological improvement. Early deep gray‐matter involvement may portend poorer recovery.

Key Clinical Message

In acute hypoglycemic encephalopathy, early MRI lesion distribution helps predict outcome: widespread deep gray‐matter involvement (basal ganglia) suggests persistent coma and poor prognosis, whereas focal cortical lesions are linked to neurological improvement.

1. Introduction

Acute hypoglycemic encephalopathy is a rare but serious complication of prolonged hypoglycemia [1]. Magnetic resonance imaging (MRI), particularly diffusion‐weighted imaging (DWI), detects characteristic brain lesions in this condition [2]. MRI findings range from focal cortical lesions to widespread deep gray matter involvement [3]. While improvements in DWI lesions are generally associated with a favorable prognosis [4], the precise associations among lesion distribution, temporal evolution, and clinical outcomes—and specifically whether basal ganglia involvement reliably predicts a poor prognosis—remain to be fully clarified.

2. Case History/Examination

2.1. Case 1

A 56‐year‐old man with a history of alcoholism and depression was found collapsed in his home, possibly unconscious for up to 24 h. Upon arrival at the emergency department, he was comatose (Glasgow Coma Scale [GCS] score: E1V1M1). His blood glucose was at 9 mg/dL, body temperature was 38.6°C, and lactate level was 2.8 mmol/L, excluding hypoxic injury. Renal and thyroid function and electrolyte levels were normal.

2.2. Case 2

An 82‐year‐old woman with a history of type 1 diabetes was found collapsed by her family, with an estimated time to hospital admission of < 3 h. Upon arrival, she was comatose (GCS score: E1V1M1) with a blood glucose level of 40 mg/dL, body temperature at 27°C (measured via a bladder catheter), and lactate level of 1 mmol/L. Renal, electrolyte, and thyroid functions were normal.

3. Methods

3.1. Case 1

Intravenous glucose was administered; however, his consciousness did not improve. He was also diagnosed with concomitant pneumonia, and empirical antibiotics were initiated. On hospital Day 2, brain MRI revealed extensive high‐signal intensities in DWI and fluid‐attenuated inversion recovery (FLAIR) sequences, involving gray matter regions, including the basal ganglia and cerebellum. While these findings are typically suggestive of acute global hypoxic ischemic injury, the clinical context strongly favored a diagnosis of hypoglycemic encephalopathy, as no other underlying conditions accounted for these findings (Figure 1A).

FIGURE 1.

Brain magnetic resonance imaging findings in Case 1 (56‐year‐old man). (A) Initial diffusion‐weighted imaging (DWI) on hospital Day 2 reveals extensive hyperintensities in the basal ganglia, cerebellum, and subcortical white matter. (B) Follow‐up DWI on hospital Day 7 reveals progression and a clearer delineation of lesions in the same regions.

3.2. Case 2

Following immediate glucose resuscitation and rewarming therapy, the patient's level of consciousness gradually improved, reaching a GCS score of 11 (E2V3M6). Initial brain MRI was performed to evaluate the neurological insult. The scan revealed scattered dot‐like hyperintensities on DWI and FLAIR images, affecting gray matter structures and the cerebral cortex, with a bilateral parieto‐occipital predominance (Figure 2A).

FIGURE 2.

Brain magnetic resonance imaging findings in Case 2 (82‐year‐old woman). (A) Initial diffusion‐weighted imaging (DWI) indicates predominant scattered dot‐like hyperintensities in the cortical gray matter. (B) Follow‐up DWI on hospital Day 7 demonstrates clear but nonprogressive lesions in the same areas.

4. Conclusions and Results

4.1. Case 1

Follow‐up MRI on Day 7 revealed lesion progression with sharper delineation (Figure 1B). Despite treatment, he remained comatose (GCS score: 3) and was transferred to a long‐term care hospital on Day 8.

4.2. Case 2

Follow‐up MRI on Day 7 revealed clearer lesion delineation (Figure 2B). She was transferred for rehabilitation on Day 26.

5. Discussion

The contrasting clinical courses of these two cases provide valuable insights into the pathophysiology of acute hypoglycemic encephalopathy. Case 1 exhibited widespread lesions affecting several gray matter regions, particularly the basal ganglia, whereas Case 2 exhibited patchy gray matter lesions. These differences may reflect clinical contrast: Case 1's prolonged, severe hypoglycemia (24 h, 9 mg/dL) may be associated with extensive deep gray matter involvement, unlike Case 2's shorter, milder insult (3 h, 40 mg/dL). Their different recoveries suggest that early widespread gray matter involvement in hypoglycemic encephalopathy predicts poor recovery of consciousness. The basal ganglia contribute to cognitive, motor, and emotional regulation, and their involvement may portend poor prognosis in hypoglycemic encephalopathy. However, this report is limited by its small sample size of only two cases; additional case‐based imaging data may help clarify the prognostic implications of lesion distribution.

Author Contributions

Yusuke Kawada: data curation, investigation, writing – original draft. Ryota Inokuchi: conceptualization, data curation, supervision, writing – review and editing. Tomoki Wada: conceptualization, writing – review and editing. Kent Doi: project administration, supervision, writing – review and editing.

Funding

The authors have nothing to report.

Ethics Statement

This case report was conducted in accordance with the ethical principles of the Declaration of Helsinki.

Consent

Written informed consent was obtained from the patient for publication of this case report and any accompanying images, and all patient data has been anonymized to protect privacy.

Conflicts of Interest

The authors declare no conflicts of interest.

Data Availability Statement

The data that support the findings of this study are available from the corresponding author, Ryota INOKUCHI, upon reasonable request.