Neurological Disorders: TIA

TIA (transient ischemic attack) or ministroke is not an uncommon nervous system disease and as the name implies the patient experiences a small stroke. Ischemia is the medical term for compromise in the circulation or arterial blood supply to an organ or tissue (loss of blood flow), so this is a temporary ischemic event related to the brain. A neurologist is frequently involved in the care of these patients with ministrokes.

By definition the TIA term is used when the stroke manifestations resolve in less than 24 hours (within a day). If manifestations remain >24 hours then it is called as a stroke instead of ministroke. For stroke manifestations lasting more than 24 hours another term called as RIND (Reversible Ischemic Neurologic Deficit) is used although this term is not commonly used nowadays rather stroke is generally used in these situations.

While the term TIA is perfect here, since the stroke symptoms are really short lasting in nature, however ministroke may not be the correct alternative term to be used for the same condition.

The terms like mini-, small, light, tiny etc are generally synonymous words all related to the quantity or magnitude of something, agree?. So irrespective of patient’s manifestations last less or more than 24 hours, the term ministroke will make more sense if manifestations are light, e.g. mild speech difficulty or weakness of a limb rather than how long it lasted.

Synonymous words related with the time duration like brief, short, short lasting, transient, evanescent etc are preferred in search of an alternative term for transient- ischemic-attack. So alternatives like “transient stroke” “brief stroke”, “short lasting stroke” etc would make more sense than miistroke.

Why alternative terms needed? TIA (Transient Ischemic Attack) is more of a medical term because the word ischemia is there, so more patient friendly alternative terms are required, agree? So depending of the clinical scenarios we may have the following 3 main terminologies; 1) Transient stroke - which means the stroke manifestations last for shorter periods, 2) Mini stroke - which means a stroke with minor deficits irrespective of the duration how long the manifestations last, and 3) Stroke, or more preferably "Full fledged stroke" - when the manifestations are both long lasting as well are present with major deficits. However some amount of confusion will continue as of now because the term ministroke is sometimes used as a synonym with transient ischemic stroke.

Is the cause for ministroke, its manifestations, investigations, treatment etc are different than a stroke?

No, the difference between a stroke & ministroke is the time duration for which the symptoms last as noted above. The causes, manifestations, investigations, treatment etc are in general similar.

The causes like poorly controlled high blood pressure, diabetes mellitus, high cholesterol, triglycerides, altherosclerosis, heart problems, vasulitis, etc are same for both stroke & ministroke.

The clinical manifestations can be ditto similar for both conditions. The only difference is how long they last as pointed above.

You order the same investigations for both conditions. Tests like echocardiogram, ECG, Holeter (all for heart ), carotid ultrasound, angiograms, ESR, ANA, RPR, cholesterol, trigycerides, blood sugar are same for both (note that not all patients require each and every test mentioned here).

The treatment lines in general are the same for both conditions.

Drugs like antiplatlet agents (aspirin, clopidogrel etc) are generally used in both conditions to prevent future attacks. Some other drugs like heparin, warfarin are also may be required for both these conditions.

The most concerning issue is the usage of clot busters (thrombolytic agents) like tPA (Alteplase) in these ministroke patients.

This drug is proved to help the acute stroke patients, but there is a risk of serious bleeding too. So its use is associated with some danger and obviously you want to give it to a patient only if it is absolutely needed.

A minisroke patient is destined to get better without any treatment, so why to take risk by injecting a clot buster?

A neurologist will always face this dilemma when attending a patient in the emergency room or hospital floor as to whether it is a ministroke or stroke? (if ministroke then no need to give risky clot buster treatment)

But it is impossible to tell the difference ahead of time. It is a retrospective diagnosis; means only time will tell what it is (if patient gets better it is TIA, if not a stroke).

So no guess work is done by the neurologist whether the manifestations will resolve by itself or not (it is futile). There are certain guidelines, if they are fulfilled then the clot buster treatment is given, if the criteria are not fulfilled then clot buster is avoided and conservative management is attempted.

To make it simple, there is no way to tell whether somebody’s stroke symptom will resolve almost completely and quickly by itself (a ministroke) or will it persist (a stroke). Even investigations will not assist much. CT scan and MRI are of no much use here.

There are patients who had their symptoms resolved totally or almost totally in less than 24 hours, but MRI came abnormal (showed stroke changes). If ministroke patients always have normal MRI of the brain then it is easier to distinguish between these two conditions and decide who should not get the clot buster (TIA patient should not get it). But unfortunately at this moment MRI criteria cannot be used.

Even if MRI can distinguish between a TIA and stroke there are other constraints for its routine applicability; there are issues like its availability, cost, certain contraindications (patients with metallic stuff in their body etc).

The significance of a TIA is it can be the warning symptom of a full fledged stroke so this condition should be identified and treated aggressively at the earliest. It is like angina for a heart attack so this condition should be taken seriously and medically attended at the earliest to prevent a full blown stroke developing in the future.