Leukoaraiosis

Conditions

Leukoaraiosis refers to white matter changes frequently seen in elderly patients with stroke, hypertension, vascular dementia, mood or gait disorders.

The term leukoaraiosis was coined in 1986 by Hachinski, Potter and Merskey to describe a rarefaction (« araiosis ») of the white matter (leuco) located around the ventricles.

These changes are observed with brain imaging techniques such as magnetic resonance imaging or CT scans.

Leukoaraiosis is not specific to a particular pathology. It frequently occurs in elderly patients with ischemic stroke, but also in those with hypertension, vascular dementia, intermittent claudication or mood disorders.

Multiple infarctions of small vessels located in the subcortical white matter can cause the condition. Patients may develop a syndrome of subcortical dementia.

It is estimated that almost all patients with vascular dementia (and about 30-50% of Alzheimer’s patients) have leukoaraiosis.

It is also associated in individuals with:

  • chronic kidney disease,
  • a metabolic syndrome,
  • retinopathy,
  • coronary artery disease,
  • high levels of homocysteine,
  • low levels of vitamin B12 and
  • high levels of C-reactive protein (a marker of inflammation).
  • Diabetes

Brain imaging indicates a reduction in the number of axons (neuron extensions) and neuroinflammation.

White matter lesions (blue arrows; frontal section of human brain)

The prefrontal cortex would be particularly sensitive to leukoaraiosis which seems to decrease the speed of information processing in the individual.

Finally, it is associated with an increased risk of ischemic stroke and cerebral hemorrhage, but also with cognitive decline and impaired gait and motor function, which are clinical features of subcortical vascular dementia.  Up to 80% of patients with leukoaraiosis have gait disorders.

The risk of dementia increases with the severity of leukoaraiosis.

Leukoaraiosis may be due to poor perfusion of the white matter irrigated by the vessels. However, this poor irrigation is insufficient to create ischemia.

Risk factors

  • Age,
  • female gender,
  • high blood pressure,
  • heart disease,
  • type 2 diabetes,
  • abdominal obesity,
  • hyperlipidemia,
  • hyperhomocysteinemia,
  • carotid stenosis,
  • tobacco use,
  • alcoholism,
  • chronic renal diseases.

Some studies have found an association between leukoaraiosis and depression. Patients with leukoaraiosis is varied and includes motor deficits, frequent falls, parkinsonism and pseudobulbar syndrome.

Classification of leukoaraiosis

The Fazekas scale is one of the most widely used in clinical practice and research. It distinguishes periventricular lesions (around a ventricle) from deep and subcortical lesions. There are 3 grades according to the severity of the lesions.

Grade 1: minimal lesions in the form of dots (punctiform) or lines. They are isolated or grouped and less than 20 mm in size.

Grade 2: moderate lesions (solitary lesions and more intense areas less than 20 mm in diameter).

Grade 3: severe lesions (solitary lesions with more intense areas of more than 20 mm in diameter).

This classification distinguishes between periventricular and deep lesions.

Conclusions

Leukoaraiosis is an important risk factor for ischemic stroke as well as for neurological and cognitive impairment.

It is a risk factor for recurrent stroke.

Patients with leukoaraiosis therefore require special care.