Editing Transient ischemic attack (section)

== Diagnosis ==
The initial clinical evaluation of a suspected TIA involves obtaining a history and physical exam (including a neurological exam).<ref name="Amarenco" /> History taking includes defining the symptoms and looking for mimicking symptoms as described above. Bystanders can be very helpful in describing the symptoms and giving details about when they started and how long they lasted. The time course (onset, duration, and resolution), precipitating events, and risk factors are particularly important.

The definition, and therefore the diagnosis, has changed over time.  TIA was classically based on duration of [[neurological]] [[symptoms]]. The current widely accepted definition is called "tissue-based" because it is based on imaging, not time. The [[American Heart Association]] and the [[American Stroke Association]] (AHA/ASA) now define TIA as a brief episode of neurological dysfunction with a [[Blood vessel|vascular]] cause, with clinical symptoms typically lasting less than one hour, and without evidence of significant [[infarction]] on [[Radiological imaging|imaging]].<ref name="pmid19423857" />

===Laboratory workup===
Laboratory tests should focus on ruling out metabolic conditions that may mimic TIA (e.g. [[hypoglycemia]]), in addition to further evaluating a patient's risk factors for ischemic events. All patients should receive a complete blood count with platelet count, blood glucose, basic metabolic panel, [[prothrombin time|prothrombin time/international normalized ratio]], and [[activated partial thromboplastin time]] as part of their initial workup.<ref name=":7">{{cite journal | vauthors = Adams HP, del Zoppo G, Alberts MJ, Bhatt DL, Brass L, Furlan A, Grubb RL, Higashida RT, Jauch EC, Kidwell C, Lyden PD, Morgenstern LB, Qureshi AI, Rosenwasser RH, Scott PA, Wijdicks EF | display-authors = 6 | title = Guidelines for the early management of adults with ischemic stroke: a guideline from the American Heart Association/American Stroke Association Stroke Council, Clinical Cardiology Council, Cardiovascular Radiology and Intervention Council, and the Atherosclerotic Peripheral Vascular Disease and Quality of Care Outcomes in Research Interdisciplinary Working Groups: the American Academy of Neurology affirms the value of this guideline as an educational tool for neurologists | journal = Stroke | volume = 38 | issue = 5 | pages = 1655–1711 | date = May 2007 | pmid = 17431204 | doi = 10.1161/STROKEAHA.107.181486 | author19 = Clinical Cardiology Council | author18 = American Stroke Association Stroke Council | author17 = American Heart Association | author21 = Atherosclerotic Peripheral Vascular Disease and Quality of Care Outcomes in Research Interdisciplinary Working Groups | author20 = Cardiovascular Radiology and Intervention Council | doi-access =  }}</ref> These tests help with screening for bleeding or [[Hypercoagulability|hypercoagulable]] conditions. Other lab tests, such as a full hypercoagulable state workup or serum drug screening, should be considered based on the clinical situation and factors, such as age of the patient and family history.<ref name=pmid23062043/> A fasting lipid panel is also appropriate to thoroughly evaluate the patient's risk for atherosclerotic disease and ischemic events in the future.<ref name=pmid23062043/> Other lab tests may be indicated based on the history and presentation; such as obtaining inflammatory markers ([[erythrocyte sedimentation rate]] and [[C-reactive protein]]) to evaluate for [[giant cell arteritis]] (which can mimic a TIA) in those presenting with headaches and monocular blindness.<ref name="Amarenco" />

===Cardiac rhythm monitoring===
An electrocardiogram is necessary to rule out abnormal heart rhythms, such as [[atrial fibrillation]], that can predispose patients to clot formation and embolic events.<ref name=":7" /> Hospitalized patients should be placed on heart rhythm telemetry, which is a continuous form of monitoring that can detect abnormal heart rhythms.<ref name="Amarenco" /> Prolonged heart rhythm monitoring (such as with a [[Holter monitor]] or implantable heart monitoring) can be considered to rule out arrhythmias like paroxysmal atrial fibrillation that may lead to clot formation and TIAs, however this should be considered if other causes of TIA have not been found.<ref name=pmid23062043/><ref name=pmid19423857/>

===Imaging===
According to guidelines from the [[American Heart Association]] and [[American Stroke Association]] Stroke Council, patients with TIA should have head imaging "within 24 hours of symptom onset, preferably with magnetic resonance imaging, including diffusion sequences".<ref name=pmid19423857/> MRI is a better imaging modality for TIA than computed tomography (CT), as it is better able to pick up both new and old ischemic lesions than CT. CT, however, is more widely available and can be used particularly to rule out intracranial hemorrhage.<ref name=pmid23062043/> Diffusion sequences can help further localize the area of ischemia and can serve as prognostic indicators.<ref name=":7" /> Presence of ischemic lesions on [[Diffusion-weighted imaging|diffusion weighted imaging]] has been correlated with a higher risk of stroke after a TIA.<ref>{{cite journal | vauthors = Redgrave JN, Coutts SB, Schulz UG, Briley D, Rothwell PM | title = 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 | journal = Stroke | volume = 38 | issue = 5 | pages = 1482–1488 | date = May 2007 | pmid = 17379821 | doi = 10.1161/strokeaha.106.477380 | doi-access = free }}</ref>

Vessels in the head and neck may also be evaluated to look for [[Atherosclerosis|atherosclerotic]] lesions that may benefit from interventions, such as [[carotid endarterectomy]]. The vasculature can be evaluated through the following imaging modalities: [[magnetic resonance angiography]] (MRA), [[CT angiography]] (CTA), and [[carotid ultrasonography]]/transcranial doppler ultrasonography.<ref name=pmid19423857/> Carotid ultrasonography is often used to screen for carotid artery stenosis, as it is more readily available, is noninvasive, and does not expose the person being evaluated to radiation. However, all of the above imaging methods have variable [[Sensitivity and specificity|sensitivities and specificities]], making it important to supplement one of the imaging methods with another to help confirm the diagnosis (for example: screen for the disease with ultrasonography, and confirm with CTA).<ref name=":12">{{cite web |title=Final Recommendation Statement: Carotid Artery Stenosis: Screening |url=https://www.uspreventiveservicestaskforce.org/Page/Document/RecommendationStatementFinal/carotid-artery-stenosis-screening |website=United States Preventive Services Taskforce|date=8 July 2014 }}</ref> Confirming a diagnosis of carotid artery stenosis is important because the treatment for this condition, [[carotid endarterectomy]], can pose significant risk to the patient, including heart attacks and strokes after the procedure.<ref name=":12" /> For this reason, the [[U.S. Preventive Services Task Force]] (USPSTF) "recommends against screening for asymptomatic carotid artery stenosis in the general adult population".<ref name=":12" /> This recommendation is for asymptomatic patients, so it does not necessarily apply to patients with TIAs as these may in fact be a symptom of underlying carotid artery disease (see "Causes and Pathogenesis" above). Therefore, patients who have had a TIA may opt to have a discussion with their clinician about the risks and benefits of screening for carotid artery stenosis, including the risks of surgical treatment of this condition.

Cardiac imaging can be performed if head and neck imaging do not reveal a vascular cause for the patient's TIA (such as atherosclerosis of the carotid artery or other major vessels of the head and neck). Echocardiography can be performed to identify [[patent foramen ovale]] (PFO), valvular stenosis, and atherosclerosis of the aortic arch that could be sources of clots causing TIAs, with [[transesophageal echocardiography]] being more sensitive than [[transthoracic echocardiography]] in identifying these lesions.<ref name=pmid19423857/>

===Differential diagnosis===
{| class="wikitable"
!Diagnosis<ref name=pmid23062043/>
!Findings<ref name=pmid23062043/>
|-
|Brain tumor
|Severe unilateral headache with nausea and vomiting
|-
|Central nervous system infection (e.g., meningitis, encephalitis)
|Fever, headache, confusion, neck stiffness, nausea, vomiting, [[photophobia]], change in mental status
|-
|Falls/trauma
|Headache, confusion, bruising
|-
|Hypoglycemia
|Confusion, weakness, [[diaphoresis]]
|-
|Migraines
|Severe headaches with or without [[photophobia]], younger age
|-
|Multiple sclerosis
|[[Diplopia]], limb weakness, [[paresthesia]], urinary retention, optic neuritis
|-
|Seizure disorder
|Confusion with or without loss of consciousness, urinary incontinence, tongue biting, [[tonic-clonic]] movements
|-
|Subarachnoid hemorrhage
|Severe headache with sudden onset and photophobia
|-
|Vertigo (central or peripheral)
|Generalized dizziness and [[diaphoresis]] with or without hearing loss
|}