Mini-Stroke:
A Term That Means Everything and
Therefore Nothing

Gary E Cordingley, MD, PhD
Few terms in medicine are as misused or abused as "mini-stroke."
As a result, real patients can get hurt or fail to receive the
treatments they need.
What is a "mini-stroke?" Doubtlessly, you've heard someone use this term before, and you
might have even seen it in print. What does this term mean to you? Probably something
less than a full-fledged stroke, which is a permanent brain injury due to a blocked blood
vessel or a hemorrhage that produces obvious clinical impairment. But, apart from that,
what exactly does it mean?

One might suppose mini-stroke to be a term with a definite meaning that everyone agrees
upon. However, this is far from the case. Just as beauty is in the eye of the beholder, so
too, the meaning of mini-stroke depends on what is in the mind of its user. Lewis Carroll's
Humpty Dumpty said it best: "When I use a word," Humpty Dumpty said, in rather a
scornful tone, "it means just what I choose it to mean -- neither more nor less." Clearly,
Humpty could have been talking about mini-strokes.

As a community-based neurologist, I have encountered several uses of this term. One is
as a substitute for "transient ischemic attack" or TIA. In this case, the term TIA already has
a specific meaning. It is an episode of obvious clinical impairment lasting fewer than 24
hours resulting from a temporary interruption of blood-flow to a portion of the brain.
Employed in this fashion, mini-stroke is a user-friendly version of a longer, precisely
defined term. If this were the only usage of mini-stroke, there would be no problem.

But, of course, mini-stroke can mean much, much more. The most unsettling use is as a
pat explanation for any small, otherwise unexplained event. This "diagnosis" emerges from
patients themselves, family members and even primary care physicians. A typical example
is that a patient had an episode of confusion or unconsciousness followed by full recovery.
Explanation: "That was a mini-stroke." Yet the more usual causes of such episodes have
nothing whatsoever to do with strokes or TIAs.

Unfortunately, labeling these events as mini-strokes means that the more likely causes are
shut off from consideration, and the unlucky patients don't receive appropriate evaluation
and treatment for their actual ailments. Moreover, by labeling such episodes as
mini-strokes, improper treatments can ensue, for example, a surgical clean-out of a carotid
artery, which in this context could cause more harm than good.

Magnetic resonance imaging (MRI) scans have led to another confusing use of the term
mini-stroke. MRIs are marvelous tools that sensitively reveal a wide variety of diseases
afflicting the brain. It's best at showing "lesions," i.e. discrete, anatomic disturbances
affecting limited portions of the brain. Sometimes, MRIs show apparent lesions that are not
disturbances at all. Unknown bright objects (UBOs) are small areas of apparent
abnormality often scattered deep within the brains of older individuals. Sometimes they do
indeed represent damage from plugged blood vessels that may or may not have produced
symptoms. But in other cases they represent other diseases entirely or even no disease at
all. For example, normal spaces next to blood vessels can appear as UBOs.

To make a long story short, any and all of these apparent disturbances can get labeled as
mini-strokes, e.g., "The scan showed that your brain is full of mini-strokes." Thus, a
mini-stroke can additionally refer to something seen on a scan which in many cases had
nothing to do with circulation or actual symptoms.

When a term like mini-stroke gets used for so many things, it becomes meaningless and
confusing. When a meaningless and confusing term is applied to real patients with real
problems, the result is bad medicine.


(C) 2006 by Gary Cordingley