persistent vegetative state

Introduction

Follows a period of coma

Etiology

• traumatic brain injury
• anoxic brain injury (ischemic stroke)
• hemorrhagic stroke

Pathology

• severe injury to the cerebral hemispheres
• sufficiently intact diencephlon & brainstem to allow
  • autonomic function
  • motor reflexes
  • sleep-wake cycles
• may involve disconnection of the precuneus from sensory input

Clinical manifestations

• absence of cognitive function
• preserved vegetative functions
  • respiration
  • blood pressure regulation
  • sleep-wake cycles
• may open eyes to external stimuli
• may show spontaneous movement
• patients do not speak, follow commands or exhibit reliable, reproducible evidence of meaningful interactions with their environment

Diagnostic procedures

• electroencephalography may be useful to detect intact awareness

Radiology

• functional magnetic resonance imaging may be useful to detect intact awareness (expensive)

Management

• diagnosis made after extended period of observation.
• prognosis for a meaningful recovery is poor.
• minimally conscious state retrospectively applied to rare individuals who do recover (in part)

Clinical trials

• among 50 patients with persistent vegetative state (age range 14-83) after 2 years
  • 21 patients died
  • 17 remained in persistent vegetative state
  • 5 evolved to minimally conscious state
  • 7 regained consciousness (with severe functional disability)
• 12 patients with persistent vegetative state
  • all either remained in persistent vegetative state or died

More general terms

• disorder of arousal; lack of awareness; impaired consciousness

Additional terms

• arousal
• minimally conscious state