Difficulties With Diagnosing Transient Ischemic Attack

Difficulties With Diagnosing Transient Ischemic Attack

Introduction

TIA (transient ischemic attack) is defined as a temporary occurrence of neurologic dysfunction, brought about by loss of blood flow (ischemia) in the spinal cord, focal brain or retinal system (Kleindorfer et al., 2005). However, there is no occurrence of the death of tissue as in acute infarction. Transient ischemic attack, which is sometimes referred to as a mini stroke, has causes as those of stroke. If not well diagnosed, it may be confused with stroke and other conditions, such as migraine, and may result in mis-treatment or poor medication. Strokes and TIAs cause similar symptoms that include aphasia, loss of vision, contralateral paralysis, and mental confusion. However, unlike stroke, transient ischemic attack’s symptoms can be resolved within a short span of time ranging between few minutes and 24 hours (Quinn et al, 2009). Studies have shown that transient ischemic attack is a risk factor for the consequence occurrence of stroke.

Causes of transient Ischemic attack

The causes of transient Ischemic attack are manifold. However, the most common is an embolus that blocks arteries in the brain. The embolus arises from atherosclerotic plague in vertebral-basilar arteries or carotid arteries. Another major cause is the blood clot (thrombus) that is commonly caused by atrial fibrillation in the atrium of the heart. Since the blockage period in transient Ischemic attack is usually short, there is no permanent brain damage that is common in cases of stroke (Edlow et al., 2006). The gradual build up of cholesterol results in the narrowing of the lumen of arteries in the brain, which in turn reduces the blood flow in the brain causing stroke. In some individuals, the cholesterol particles come from the heart and enter brain vessels resulting in stroke. Other reasons that may cause transient ischemic attack are increased viscosity of blood that result from blood diseases, medical conditions such as hypertension, diabetes mellitus, migraine, heart disease, such as atrial fibrillation and hypercholesterolemia.

Risk factors of transient Ischemic attack

The risk factors are high blood pressure, family history of TIA or stroke, tobacco smoking, diabetes mellitus, old age where people who are over 55 years old are at high risk and gender status where males have a higher risk of controlling TIA although females are more vulnerable to stroke related deaths (Rothwell and Warlow, 2005).

Signs and symptoms

Signs and symptoms vary from one individual to the other, and are based on the side of the brain that is affected. Basically, the most frequent symptoms are difficulty in speaking, temporary loss of vision, dizziness, tingling or numbness, poor balance, hemiparesis, and impairment of consciousness (Kennedy et al., 2007). There have been noted cases involving partial and temporal paralysis that affect the tongue and the face. The symptoms of transient Ischemic attack last for a short span of time and may take some seconds or few minutes.

Test and diagnosis of transient Ischemic attack

Since TIA is short –lived, a health expert may diagnose it basing on medical history of the patient rather than the results found during neurologic and physical examination. In order to determine the cause of transient ischemic attack and analyze the risk of stroke, the health expert may undertake a number of checks that include;

Carotid ultrasonography, which involves a transducer or a wand like device that sends sound waves of high frequency through the patient’s neck. The sound waves record the images of the tissues and so the health expert can assess the images recorded in the screen to determine if there is clotting or constriction on the carotid artery.

Physical tests and examination involves assessment of risk factors of stroke or transient Ischemic attack that include high levels of cholesterol, high blood pressure, presence of high concentrated homocysteine and diabetes. A stethoscope may be used to atherosclerosis which ophthalmoscope may be utilized to observe cholesterol fragments.

CT (computerized tomography) scanning involves scanning of the patient’s head by using x-ray beams to assess a composite, 3-D look in the patient’s brains.

MRI (magnetic resonance imaging that uses magnetic fields to generate 3-D view in the patient’s brains.

Echocardiography is the use of a transducer placed on the patient’s chest to create an ultra sound image of the heart.

Arteriography involves use of dye, catheter and X-ray to provide images of brain arteries that are normally seen through X-ray imaging.

Blood tests involve screening of blood to check abnormalities in blood components such as serum cholesterol, blood glucose level and homocysteine count.

In analyzing whether there are difficulties with diagnosing TIA, it is imperative to understand that Transient ischemic attack is no longer considered as benign but rather a critical aspect of impending stroke. In fact, it is a major risk factor for transient ischemic attack. Failure to recognize the condition promptly and assess the warning signs means missing an opportunity of mitigating permanent death and stability (Lavallée et al, 2007). Different research studies have shown that an estimated 10% of 90 day risk of stroke occurs after the incidence of transient Ischemic attack. The 90-day risk of stroke is higher in cases where transient ischemic attack emanate from stenosis of internal carotid artery. Reported cases of symptoms of transient ischemic attack should be booked for emergency assessment and treatment. The patients that come to the hospital within the 3 hrs after showing the symptoms are required to pass through some stages (Rothwell et al, 2007). The process begins with physical examination, followed by analysis of the history of the condition, and ends with the laboratory testing to determine if the patient would require thrombolytic therapy. The first test should involve full blood count that involves prothrombin time, platelet count, partial thromboplastin time, international normalized ratio, and glucose and electrolyte levels. In the physical examination, computed tomographic scanning of patient’s head should be conducted immediately to ascertain that there is no presence of brain mass or hemorrhage. There are cases where TIA is misdiagnosd and confused with other ailments, such are seizure, migraine, and peripheral neuropathy.

Basing on increased awareness of brain ischemia and the new treatment options that have been introduced, a working health group has redefined TIA(transient ischemic attack) as a brief, short lived phenomenon of neurological dysfunction brought about by retinal ischemia or focal brain , whose clinical symptoms last less than one hour and do not exhibit acute infarction evidence

(Dhamoon et al, 2006). However, this definition does not emphasize on the urgency need of recognizing transient ischemic attack as a vital warning of an imminent stroke that is important in enhancing prompt evaluation and treatment of transient ischemic attack to prevent permanent brain ischemia.

Epidemiology

In the United States, approximately 200,000 to 500,000 transient ischemic attack cases occur annually. One research study found that 25% of transient ischemic attack cases presented for emergency had adverse effects within 3 months(90 days).10% of the cases had stroke with a large proportion of the patients exhibiting disabling or fatal stroke (Giles and Rothwell, 2007). More than 50% of adverse cases occurred within the first four days after the onset of transient ischemic attack cases. Conspicuously, approximately 10.5% of patients with transient ischemic attack cases reported to the emergency department with stroke, with about half contracting stroke within the first 48 hours after the initial diagnosis and treatment of transient ischemic attack (Quinn et al, 2009). 2.6% of the patients with transient ischemic attack were hospitalized for cardiac cases that included unstable angina, ventricular arrhythmia, cardiac arrest and heart failure.

Clinical presentation and analysis

Generally, TIA manifests itself as a syndrome rather than as a symptom or a sign. Further, there is no reliable way of determining if the abrupt occurrence of neurologic deficit is a manifestation of reversible Ischema without brain damage occurring at subsequent stages or if Ischema will lead to permanent damage of brain tissue as in the case of stroke (Johnston et al, 2000). As such, all patients with transient ischemic attack symptoms should be subjected to thorough medical evaluation.

In order to handle transient ischemic attack cases, office staff needs to be well trained and educated about the neurologic symptoms that accompany it in order to achieve optimal results in the medication process. In US and other developed countries where there is hi- tech medication processes, there is the use of ABCD2 triage system.ABCD2 triage system is a clinical prediction rule that was established in 2007 to detect the threat of recurrent stroke after the occurrence of TIA(transient ischemic attack. The ABCD2 has become part of the international management of transient ischemic attack (Quinn et al, 2009). The score is part of a form that combines clinical rules and standardized protocol for emergency referrals to secondary care of patients.Currently, ABCD2 score is utilized in most of the medical centers and most of the studies indicate that approximately 50% of strokes in the first three months occurred in the first 7 days. A large percentage of patients taken under emergency care for stroke or TIA have a large ABCD2 scare of more than 3 and had high short term risk of TIA, stroke and other heart ailments. However, patients who have low risk ABCD2 score of less than 4 may possess high risk prognostic indicator such as large artery atherosclerosis, atrial fibrillation, and diffusion weighted imaging abnormalities (Rothwell et al, 2005). The ABCD2 triagle system has been essential in differentiating different categories of neurologic disorder hence avoiding misdiagnosis and treatment.

Differential Diagnosis

The common imitator of transient ischemic attack is migraine, post-ictal states, glucose derangement, seizure and tumors. Typically, TIA’s onset is usually rapid and its maximal intensity is attained within minutes (Josephson et al, 2008). The fleeting cases experienced in TIA usually last in about one or two seconds. Non specific symptoms such as lightheadedness, fatigue and bilateral rhythmic shaking of hands and legs are less likely manifestation of acute cerebral ischemia.

Differentiating migraine aura and TIA can be a very difficult process. Previous history of migraine, young people and associated Nausea, headache or photophobia are more symptomatic of migraine than transient Ischemic attack. Generally, migraine tends to exhibit a marching quality, for instance symptoms such as tingling may progress continuously from fingers to the face. Further, Migraine aura is likely to likely to have a gradual beginning and resolution, but the duration of the symptoms are longer than those of TIA.

Case

A 71 year old woman was cleaning her house when her left became weak and had difficulty standing. Her left arm and her face had become numb. She called her elder son who assisted her on a chair for her to rest. The symptoms resolved within three minutes .The family doctor was called who decided that since the condition had resolved, she could not go to the hospital as he just offered her a dosage of aspirin. In this case, the woman had suffered a transient ischemic attack of which resolved by itself. It was decided that the risk factor of the woman’s condition was high cholesterol diets, high blood pressure and diabetes. In this case, proper diagnosis was not conducted and so TIA as a risk factor was not arrested (Quinn et al, 2009). After three months, the woman developed similar conditions of high intensity and they involved poor balance, impairment of consciousness, dizziness and loss of vision. She was taken to emergency depart and was diagnosed of stroke. Basing on this case, the family doctor did not put much consideration on the TIA condition which in turn developed into stroke.

Treatment of transient Ischemic attack

The basis of treatment of transient Ischemic attack is the underlying cause. To minimize the risk of recurrence, it is imperative for patients to undertake lifestyle changes that reduce the risk factors. Medication includes the use of anti-coagulant drugs such as warfin and heparin. Anti-platelet medication such as aspirin may also assist in minimizing agglutination of platelets. Surgery may also be appropriate in cases where stenosis within the carotid artery exceeds 70% (Redgrave et al, 2007).

Conclusion

Transient ischemic attack, which takes a relatively short time to resolve, may be difficult to diagnose, because of its similarities of the symptoms with other conditions such as stroke. The Similarities of the symptoms, failure by health experts to accord it utmost attention and the short time it takes to resolve make it a major risk factor of stroke. However, the hi-tech medication processes employed in the contemporary medical settings such as the use of CT scan have made it possible to detect and arrest most of transient ischemic attack cases. Further, the use of the ABCD2 triagle system has played an important role in differentiating different categories of neurologic disorder thus avoiding wrong diagnosis and treatment. Basing on the 71 year old case where TIA was not arrested, resulting in stroke, medical experts needs to have sufficient information about the condition in order to minimize cases where TIA develops into stroke.

References

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Edlow, J.A, Kim, S. Pelletier, A.J, and Camargo CA., 2006. National study on emergency department visits for transient ischemic attack, 1992–2001. Academic Emergency Medicine 13(6):666–672.

Giles, M.F., and Rothwell, P.M., 2007. Risk of stroke early after transient ischaemic attack: a systematic review and meta-analysis. Lancet Neurology 6(12):1063–1072.

Johnston, S.C., Gress, D.R., Browner, W.S., and Sidney, S., 2000. Short-term prognosis after emergency department diagnosis of TIA. Journal of the American Medical Association 284(22):2901–2906.

Josephson, S.A., Sidney, S., Pham, T.N., Bernstein, A.L., and Johnston, S.C., 2008. Higher ABCD score predicts patients most likely to have true transient ischemic attack. Stroke 39(11):3096–3098.

Kennedy, J., Hill, M. D., Ryckborst, K.J., Eliasziw, M., Demchuk, A.M., and Buchan, A.M., 2007. Fast assessment of stroke and transient ischaemic attack to prevent early recurrence (FASTER): a randomised controlled pilot trial. Lancet Neurology 6(11): 961–969.

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Redgrave, J.N., Coutts, S.B., Schulz, U.G., Briley, D., and Rothwell, P.M., 2007. Systematic review of associations between the presence of acute ischemic lesions on diffusion-weighted imaging and clinical predictors of early stroke risk after transient ischemic attack. Stroke 38(5):1482–1488.

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Rothwell, P.M., Giles, M.F., and Flossmann, E., 2005. A simple score (ABCD) to identify individuals at high early risk of stroke after transient ischaemic attack. Lancet 366(9479):29–36.