Anoxia

What is anoxia/hypoxia?

• Absence/reduction of O2 supply to tissues (brain tissue in this case)

Common causes of anoxia (5)

• Cardiac arrest (most common)

• Attempted suicide (particularly carbon monoxide poisoning)

• Hanging

• Near-drowning

• Stroke or TBI

4 types of anoxia

• Anoxic anoxia

• Anaemic anoxia

• Toxic anoxia

• Stagnant anoxia / hypoxic ischemia

Anoxic anoxia description

• Insufficient O2 supply in air

Anaemic anoxia

• Blood supply to brain is insufficiently oxygenated (due to anaemia, low carrying capacity of haemoglobin)

Toxic anoxia

• Toxins prevent O2 in blood from being used

  • E.g. carbon monoxide

Stagnant anoxia / hypoxic ischemia

• Internal condition physically limits blood supply to brain tissue

Comparing brain regions in terms of vulnerability to damage from anoxia

• Basal ganglia + watershed cortical regions (which are supplied by distal arterial branches) are the most vulnerable

• Areas responsible for autonomic functions (like brainstem) are most resistant to damage

Breakdown of sequelae of anoxia (1→2, 1→2, 1, 1, 1,)

• Cognitive

  • Memory deficits

  • Exec dysfunction

• Emotional

  • Depression

  • Anxiety

• Visuospatial/perceptual deficits

• Severe intellectual impairment (~25%)

• Disorders of consciousness

  • Vegetative state (VS)

  • Minimally conscious state (MCS)

Treatment (2)

• Targeted early intervention like the “stand still… move on intervention” includes early cognitive screening, psychoeducation, practical support + emotional counselling

^^so basically a holistic and individualised approach like is appropriate for other brain injuries

• External memory aids + environmental structuring to aid in often extensive damage to memory + exec functions