Can sudden-onset unawareness be caused by a transient ischemic attack?

A sudden experience of mental fog or what seems like unawareness to an observer can be quite unsettling — especially to anyone who knows what a transient ischemic attack is.

“Yes, a TIA can cause disorientation, amnesia or even loss of consciousness,” says Rob Lapporte, MD, who is board certified in emergency medicine.

This means that a person can drop to the floor as a result of a TIA, sustaining injury from the fall.

Such an injury could involve the brain from head trauma, or a broken hip from the impact.

Transient ischemic attacks are associated with the following symptoms, all sudden-onset:

  • weakness or a heavy feeling on one side of the body or in a limb
  • numbness or paralysis in a limb
  • facial drooping
  • slurred or nonsensical speech
  • dizziness
  • blurry vision
  • mental confusion.

Dr. Lapporte explains, “Think of it this way. The brain has many functions, and every part of the brain requires blood flow to stay functional. 

“If any portion of the brain is deprived of blood (therefore, oxygen), it will cease to function properly.

“While this [loss of consciousness, disorientation or unawareness] may not be the most common presentation of a patient with a TIA, it’s certainly possible.”

How possible is unawareness or loss of consciousness from a TIA?

“Loss of consciousness is extremely rare in TIAs (but not impossible),” states a report in Practical Neurology (2014 Feb; 14(1): 23–31).

Much more likely than not, a seemingly sudden loss of consciousness is caused by something other than a TIA, such as a rapid and big drop in blood pressure, or an abnormal heart rhythm.

When a TIA actually does cause a loss of consciousness (and remember, this is very rare), it’s when the blood clot is located in the brainstem or thalamus.

A sudden bout of mental fog, unawareness or some other altered state of consciousness is never normal — even if it is brief — and it may even be a small seizure. A prompt medical evaluation is warranted.

Dr. Lapporte has been practicing evidence-based clinical medicine in emergency rooms and urgent care centers for 25+ years. His experience includes that of medical director for Legacy ER and Urgent Care.
Lorra Garrick has been covering medical, fitness and cybersecurity topics for many years, having written thousands of articles for print magazines and websites, including as a ghostwriter. She’s also a former ACE-certified personal trainer.  

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Top image: Shutterstock/forma82
Source  ncbi.nlm.nih.gov/pmc/articles/PMC3913122/