Hyperekplexia in a patient with a brainstem vascular anomaly

Acta Neurol Scand. 1999 Apr;99(4):255-9. doi: 10.1111/j.1600-0404.1999.tb07358.x.


Objectives: To describe a patient with a clinical picture suggestive of idiopathic hyperekplexia (IH), who was later found to harbour a subtle brainstem vascular anomaly.

Patient: A 35-year-old man, 4 years earlier, developed sudden jumping and falling in response to unexpected sensory stimuli.

Results: Neurological examination was normal. Electromyography showed an excessively large and non-habituating motor startle response. There were no mutations of the alpha1 subunit of the inhibitory glycine receptor which cause hereditary hyperekplexia. Although all these findings were consistent with a diagnosis of IH, a blink reflex study showed an enhanced recovery curve suggestive of a brainstem lesion. A detailed MRI study revealed a subtle vascular anomaly involving the lower brainstem.

Conclusion: This is the first report of sporadic hyperekplexia related to a brainstem vascular anomaly. Subtle damage to the brainstem should always be excluded in patients with sporadic hyperekplexia, regardless of the coexistence of additional clear-cut neurological symptoms.

Publication types

  • Case Reports

MeSH terms

  • Adult
  • Blinking / genetics
  • Blinking / physiology
  • Brain Stem / blood supply*
  • Cerebral Arteries / abnormalities*
  • DNA Mutational Analysis
  • Electroencephalography
  • Humans
  • Magnetic Resonance Imaging
  • Male
  • Movement Disorders / diagnosis*
  • Movement Disorders / genetics*
  • Point Mutation / genetics
  • Sleep / physiology
  • Wakefulness / physiology