Don't ignore these atypical TIA symptoms!

*Only for medical professionals' reference, read alert! The risk of stroke after atypical TIA is also high, and the overall number of TIA diagnoses may increase by 50%.

Transient ischaemic attacks (TIA) are common neurological problems.
In a population-based cohort study from 1948 to 2017, the total estimated incidence of TIA was 1.
19/1000 persons/year.

The incidence rate increases with age; the incidence rate for the 45 to 54-year-old age group is 0.
22/1000 people/year, and the incidence rate for the 85-94 year-old age group is 4.
88/1000 people/year [1].

Definition of TIA Traditional time-based definition: TIA was originally defined as sudden, transient, and reversible focal neurological symptoms caused by a short-term cerebral blood supply shortage in the carotid artery or vertebral-basal artery system ( (Including brain, spinal cord or retina) disorders, usually complete recovery within 30 minutes, usually not more than 24h; tissue-based definition: in the tissue-based definition, TIA is caused by focal brain, spinal cord or retinal ischemia A brief episode of neurological dysfunction without acute cerebral infarction [1].

As many as 25% of strokes are accompanied by TIA before they occur, and the early risk of stroke after TIA is also high, requiring immediate intervention and treatment.

In particular, antiplatelet therapy is needed because these drug treatments can greatly reduce the risk of early stroke recurrence.

Since most TIA patients do not have acute ischemic lesions on imaging, in clinical practice, our diagnosis of TIA still depends on the patient’s description of symptoms, and more importantly, clinicians’ correct understanding and recognition ability of TIA .

Clinical symptoms of TIA The current diagnostic criteria for TIA by clinicians is still based on the expert consensus of the National Institute of Nervous System Diseases and Stroke (NINDS) (see Figures 1, 2).

(1) Typical TIA symptoms include: limb weakness: one or more body segments (face, arms, hands, legs) suddenly appear short-lived motor weakness; language disorder: sudden short-term expression or understanding impairment, or both Sensory loss: sudden transient loss of sensory in two or more body segments (face, arms, hands, or legs); hemianopia or quadrant blindness: sudden transient loss of vision (same type of hemianopia or quadrant blindness) in the visual field Vision); monocular vision loss: sudden onset of transient monocular vision loss; vertigo+: sudden transient dizziness with other TIA symptoms; diplopia+: sudden transient diplopia with other TIA symptoms; articulation Disorder+: sudden onset of transient dysarthria and other TIA symptoms; ataxia+: sudden onset of transient ataxia plus other TIA symptoms.

(2) Atypical TIA symptoms include: only vertigo: sudden non-recurrent isolated vertigo (with or without nausea or vomiting), not caused by head movement or trauma, and no related earache, tinnitus or hearing loss ; Except for cases of non-specific dizziness or mild dizziness; only ataxia: sudden transient gait instability without any other reason; only diplopia: no obvious eye (such as retinal detachment) Or the sudden onset of transient binocular diplopia due to neuromuscular reasons; only speech disorder: sudden transient isolated slurred speech; only bilateral vision loss: sudden onset transient isolated bilateral visual impairment (not including Hemi blindness or quadrant vision), no related positive symptoms; single sensory loss: sudden transient numbness of one side of the body (face, arms, hands, or legs).

Ps: The main point of contention for atypical TIA is that the occurrence of these symptoms may not be caused by vascular ischemia, but may also be caused by non-vascular factors.

Figure 1: Typical TIA symptoms Figure 2: Atypical TIA symptoms Atypical TIA related research Although it is known that the long-term risk of stroke after typical TIA symptoms is high, there are few published data on the time and prognosis of atypical TIA.

In clinical practice, TIA patients with atypical symptoms are usually not treated or considered as TIA for treatment.
However, considering the benefits of secondary intervention immediately after the occurrence of TIA, if there is an early stroke risk after atypical TIA Increase, so it is vital that patients receive timely treatment! In order to clarify the prognosis of TIA patients with atypical symptoms, a scientific research team from the University of Oxford in the United Kingdom conducted a related study on the risk of stroke and cardiovascular events in patients with atypical TIA, and the results were published on March 6, 2021.
Published in The Lancet.

Figure 3: Screenshot of the cover of the paper.
This is a population-based longitudinal cohort study from the United Kingdom.
Between April 1, 2002 and March 31, 2018, a total of 2878 cases of mild ischemic stroke were screened (N=1287), patients with classic TIA (n=1021) or atypical TIA (n=570) were prospectively evaluated, and the follow-up date was until October 1, 2018 (median 5.
2 years).

Among them, patients with atypical TIA include isolated vertigo, isolated ataxia, isolated diplopia, isolated speech disorder (slurred speech) without aphasia, isolated bilateral vision loss or isolated unilateral sensory loss, involving Two or more body parts (face, arms, hands or legs).

According to secondary prevention guidelines, patients with baseline mild ischemic stroke (National Institutes of Health Stroke Scale score <5), classic TIA or atypical TIA were treated.

Key observation indicators: the risk of stroke (7-day, 90-day, and 10-year risk) and the risk of all major vascular events.

▌ Research results 1.
During the follow-up of 17,009 people/years, 577 patients had their first stroke recurrence after the index event (after the first symptom), of which 279 occurred after a minor stroke and 199 occurred after a classic TIA , 99 people occurred after atypical TIA.
The 90-day stroke risk of atypical TIA patients is similar to that of classic TIA patients [10.
6% (95%CI 7.
8-12.
9) vs 11.
6% (9.
6-13.
6)]; risk ratio [(HR ) 0.
87 95%CI 0.
64-1.
19; p=0.
43]; similar 90-day stroke and acute cardiac events (such as myocardial infarction and sudden cardiac death) risk is [11.
2% (95%CI 8.
6-13.
7) vs 12.
9 %(10.
9-14.
8); p=0·29] (see Figure 4).

Figure 4: The 90-day stroke risk of patients with classic TIA and atypical TIA 2.
The 10-year stroke risk of patients with atypical TIA is lower than that of patients with classic TIA [15% (95%CI 11.
1-18.
9) vs 20.
1% (95%CI) 16.
6-23.
6); HR1.
5 (95%CI 1.
1-2.
0); p=0.
010]; 10-year risks of all major vascular events in patients with atypical TIA and classic TIA are similar [27·1% (95%CI 22 ·8–31.
4) vs 30·9% (95%CI 27.
2–33.
7); p=0.
12] (see Figure 5).

Figure 5: 10-year risk of all major vascular events in patients with atypical TIA, classic TIA, and mild ischemic stroke 3.
In addition, at baseline, for atypical TIA and classic TIA, including atrial fibrillation and patent foramen ovale The prevalence of stroke risk factors including arterial stenosis is also similar [3].

Conclusion Patients with atypical TIA have a higher risk of early and long-term stroke, and at baseline, patients with atypical TIA and classic TIA have similar cardiovascular stroke risk factors.

If the non-classical TIA is considered a cerebrovascular event, the total number of TIA diagnoses can increase by 50% [3].

For patients with atypical TIA, there is still a need for early intervention and treatment.

Reference materials: [1]Lioutas VA,Ivan CS,Himali JJ,et al.
Incidence of Transient Ischemic Attack and Association With Long-term Risk of Stroke.
JAMA 2021;325:373.
[2]Easton JD,Saver JL,Albers GW,et al.
Definition and evaluation of transient ischemic attack: a scientific statement for healthcare professionals from the American Heart Association/American Stroke Association Stroke Council; Council on Cardiovascular Surgery and Anesthesia; Council on Cardiovascular Radiology and Intervention; Council on Cardiovascular Nursing; and the Interdisciplinary Council on Peripheral Vascular Disease.
The American Academy of Neurology affirms the value of this statement as an educational tool for neurologists.
Stroke 2009;40:2276.
[3]Tuna MA,Rothwell PM;Oxford Vascular Study.
Diagnosis of non -consensus transient ischaemic attacks with focal, negative, and non-progressive symptoms:population-based validation by investigation and prognosis.
Lancet.
2021 Mar 6;397(10277):902-912.
doi:10.
1016/S0140-6736(20)31961-9.
PMID:33676629;PMCID:PMC7938377.