Advertisement

Welcome to the new AJNR, Updated Hall of Fame, and more. Read the full announcements.

AJNR is seeking candidates for the position of Associate Section Editor, AJNR Case Collection. Read the full announcement.

 

Hypoglycemic Encephalopathy

  • Background:
    • Hypoglycemia and severe hypoglycemia are defined as plasma glucose levels of 70 mg/dL (3.9 mmol/L) and 40 mg/dL (2.2 mmol/L), respectively.
    • It is more common in patients with diabetes, usually occurring as a complication of therapy with insulin or long-acting sulfonylurea drugs. Other causes are insulin-secreting tumors, sepsis, and hepatic or renal failure.
    • This patient had recurrent episodes of hypoglycemia secondary to the use of a long-acting oral hypoglycemic agent.
  • Clinical Presentation:
    • Autonomic: sweating, trembling, palpitations, and anxiety
    • Neuroglycopenic: weakness, confusion, personality changes, seizures, and transient memory loss
    • In general, autonomic symptoms usually develop before neuroglycopenic symptoms. Severe hypoglycemia may present with altered mental state or coma. Hemiparesis or quadriparesis in patients mimics a stroke.
  • Key Diagnostic Features:
    • MRI, especially DWI, is the best modality for early diagnosis of hypoglycemic encephalopathy.
    • Three distinct imaging patterns are described: 1) predominant gray matter involvement affecting the cortex, neostriatum, and hippocampi; 2) predominant white matter involvement affecting the periventricular white matter, internal capsule, and splenium of the corpus callosum; and 3) a mixed pattern involving both the gray matter and white matter.
    • The diffusion changes depend on the severity and duration of hypoglycemia and represent cytotoxic injury, which may be reversible on rapid correction of hypoglycemia. The DWI changes are usually bilateral; however, asymmetric and unilateral changes are also described.
    • Asymmetric DWI changes in hypoglycemia are related to regional imbalances between energy supply and demand, spreading depression, or an excitotoxic mechanism.
    • The thalamus, brain stem, and cerebellum are generally spared.
  • Differential Diagnoses:
    • Hypoxic-ischemic brain injury: preceding hypoxic or ischemic event; symmetric globus pallidus or thalamic involvement may help in differentiation
    • Creutzfeldt-Jakob disease (CJD): different clinical presentation; characteristic cortical ribbon or hockey stick sign
    • Ischemic infarct: follows arterial territory
    • Seizure-related changes: may have similar imaging pattern; history and laboratory work-up may help distinguish
  • Treatment:
    • Prevention of hypoglycemia should be the aim in patients with diabetes mellitus, with an appropriately chosen drug regimen and dietary modifications.
    • Mild hypoglycemia is usually managed by oral ingestion of glucose.
    • Moderate to severe hypoglycemia is managed by immediate intravenous injection of 25% dextrose or intramuscular glucagon.
March 12, 2020

A 52-year-old man with type 2 diabetes mellitus on oral hypoglycemic agent; history of fever, vomiting, and loss of appetite for 3–4 days and sudden loss of consciousness in the morning of the day of presentation; no history of seizure

View Case
Advertisement
Subscribe to RSS - Hypoglycemic Encephalopathy