As in any neurological consultation 90% of the diagnosis is made on the basis of history and a little more is added by way of focused examination. A quick and focused history is important in the thrombolysis setting. A more relaxed and thorough history can be taken when there is no rush to thrombolyse. In the thrombolysis setting the main decision maker for thrombolysis should do this themselves and make sure that they have made all reasonable attempts to make sure the story is one of acute stroke and that onset time and stroke duration have been defined and contraindications excluded. This takes some skill and experience. They key here is to have a good stroke proforma which contains all the crucial data that needs collected prior to a thrombolysis decision and a checklist to ensure that everything has been checked and nothing missed in haste.
Taking a focused history
The history of stroke is usually a sudden loss of function that is unexpected. The patient is completely well until there is a loss of speech or vision, or power or sensation or balance. If there is a prodrome or a subacute onset then begin to think of other diagnoses. There are some strokes which have a stuttering onset - often called capsular warning syndromes. A prodrome may be palpitations in a patient with AF related stroke. Neck pain for days or hours before a stroke might suggest a cervical dissection. Fever and stigmata of endocarditis may suggest cardioembolism as a cause. However the most common presentation is as stated sudden asymmetrical loss of function which is totally unexpected and came on over a minute or so.
- Suddenness of onset: If a patient can give a precise time of onset this increases the accuracy of a stroke diagnosis. The occlusion of a blood vessel by thrombosis or embolism leads to a sudden and dramatic clinical change in those cells downstream which need a constant supply of oxygen and glucose to maintain the high metabolic demand. There is a sudden onset of symptoms and signs within seconds or developing as neuronal dysfunction continues. In some strokes there is a stuttering onset usually with thrombotic type strokes where a stenosis means that flow is critical but has not yet or is slowly occluding. Embolic strokes are classically maximal at onset and can rapidly improve. The stuttering courses are uncommon but when they occur they may make one question the diagnosis but this still can occur with thrombotic type strokes and the history must be balanced with the other clinical and radiological findings.
- Unexpected: A prodrome or non specific symptoms in the days or hours immediately prior to the stroke can be unusual unless it is directly related to the cause of the stroke e.g. Pain in the neck from a dissection the hours before a stroke. However weight loss, headache, lethargy or other symptoms building up to the stroke episode is unusual and should warrant a search for other causes. Most patients felt 'normal' and were carrying on their normal routine up to the moment the stroke started.
- Focality: The signs and symptoms are focal symptoms and relate to the volume of brain and its importance and its functional role. The signs can be explained by a disruption in blood supply to a particular discrete area of the brain and to a particular arterial (or rarely venous) occlusion. Patients may have weakness, loss of speech but some signs may be more subtle such as hemianopia.
- Laterality: Strokes affect the brain and therefore in almost all cases signs and symptoms are found on the opposite side. Bilateral signs or symptoms are very uncommon though it is not impossible to have bilateral simultaneous strokes at the same time. I would need a lot of evidence to thrombolyse, possible an MRI-DWI. As always there are the very rare exceptions of basilar strokes but these are usually accompanied by brainstem signs and visual loss.
- Negative: Patients with stroke display 'Negative' symptoms, a loss of function e.g loss of power, co-ordination, vision, speech. Symptoms which are predominantly "positive'' - e.g. limb jerking or twitching of the face or paraesthesia or flashing lights always warrant consideration of an irritative focus and perhaps a focal epilepsy. Stroke may cause some tingling or even flashing lights or jerking but the overriding clinical signs will tend to be negative.
Negative and Positive symptoms
The symptoms and signs of stroke are usually negative i.e. loss of vision, loss of power, loss of coordination, loss of speech. Positive symptoms such as flashing lights or tingling or unconscious movements can be seen with stroke but if they are dominant then this may make one consider alternate diagnoses such as focal epilepsy or migraine or a focal lesions possibly an SOL. I have even seen hypocalcaemic patients with facial twitches and tingling referred to the TIA clinic.
|Symptoms and signs that should make one question a stroke or TIA diagnosis|
Stroke presentation is classically sudden and unexpected and if the stroke came on acutely whilst awake then it should be attempted to decide at exactly what time it came on. If the onset was over hours or longer then other diagnoses should be considered and certainly without a clear onset time thrombolysis should be avoided.
A lack of prodrome is much the same as the above point. A prodrome of symptoms for days or hours before the stroke such as headache, malaise, fever and weight loss should make one consider other diagnoses. Stroke when it does occur comes on instantly. There is rarely any progression and patients are at usually at their worst at onset. There are rare circumstances in which there is a stuttering onset to the stroke usually seen with thrombosis that can cause recurrent symptoms prior to the stroke. The capsular warning syndrome can have recurrent lacunar stroke symptoms prior to the stroke but these presentations are rare. Occasionally a stroke may be preceded by a TIA.
There are a few exceptions- a carotid or vertebral dissection can be associated with severe neck, retro-orbital or occipital pain for days or hours before a stroke. Usually in a younger person. Heart failure or palpitations may suggest AF. Recent chest pain can suggest a recent MI and LV thrombus. Dyspnoea can suggest a dilated cardiomyopathy and again cardioembolic stroke. Embolic strokes are classically maximal at onset. Thrombotic strokes are occasionally stuttering. New murmurs, a history of valve disease and pyrexia may suggest endocarditis and septic emboli.
It is not uncommon that one has to determine if this is a stroke or a mimic
|Findings that support a stroke diagnosis|
|Definite focal symptoms|
|Exact time of onset|
|Patient was well in the last week|
|NIHSS > 10|
|OCSP classification was possible|
|Abnormal visual fields|
|Vertigo and lower limb ataxia are unreliable for POCS|
Localising clinical findings in stroke
|Useful||Focal weakness or sensory loss or pain, visual loss, language issues, anosognosia, neglect|
|Lack of focus||Isolated Vertigo, imbalance, slurred speech all of limited use. Not stroke specific unless as a syndrome of multiple issues e.g. Lateral medullary or with brainstem or long tract signs|
|Imprecise||Fatigue, headache, dizziness, insomnia, memory loss are not very useful in diagnosis of stroke|
|SIGN OR SYMPTOM||LOCATION CEREBRAL HEMISPHERES|
|Unilateral weakness or sensory complaints||Contralateral cerebral hemisphere|
|Language dysfunction||Left hemisphere (frontal, temporoparietal)|
|Spatial disorientation||Right hemisphere (parietal and occipital)|
|Anosognosia (lack of insight into deficit)||Right hemisphere (parietal)|
|Hemivisual loss||Contralateral hemisphere (occipital, temporal, and parietal)|
|Flattening of affect or social disinhibition||Bihemispheric (frontal and limbic)|
|Alteration of consciousness||Bihemispheric (diffuse)|
|Alteration of memory||Bihemispheric (hippocampus, fornix, amygdala, and mammillary bodies)|
|SIGN OR SYMPTOM||CEREBELLUM|
|Limb clumsiness||Ipsilateral cerebellar hemisphere|
|Unsteadiness of gait or posture||Midline cerebellar structures|
|SIGN OR SYMPTOM||BASAL GANGLIA|
|Slowness of voluntary movement||Substantia nigra and striatum|
|Involuntary movement||Striatum, thalamus, and subthalamus|
|SIGN OR SYMPTOM||BRAIN STEM|
|Contralateral weakness or sensory complaints in the body with ipsilateral weakness or sensory complaints in the face||Midbrain, pons, and medulla|
|Double vision||Midbrain and pons|
|Vertigo||Pons and medulla|
|Alteration of consciousness||Midbrain, pons, medulla (reticular formation)|
|SIGN OR SYMPTOM||SPINAL CORD|
|Weakness and spasticity (ipsilateral) and anesthesia (contralateral) below a specified level||Corticospinal and spinothalamic tracts|
|Unsteadiness of gait||Posterior columns|
|Bilateral (can be asymmetrical) weakness and sensory complaints in multiple contiguous radicular distributions||Central cord|
Typical Stroke Mimics
|Seizure (17%)||Seizures which are unwitnessed resulting in a comatose patient being admitted with a possible unilateral weakness can often be directed to stroke team. If there is a clear history of seizure then the differentiation is easier. However, some patients may be having a focal seizure with generalisation after an old stroke. A seizure is rare in the acute stroke setting. All should have a CT. Management will depend on findings. Stroke patients unless there is a catastrophic lesion which should be visible on CT should not be comatose with a few rare exceptions.|
|Systemic infection (17%)||Patients with old strokes who get sepsis or another metabolic disturbance may have return of their original stroke symptoms. I call these OSSIs "Ozzies" (Old Stroke Systemic illness). CT will typically show the old lesion. CRP /WCC may be elevated. Common in the elderly patient. Often UTI or chest infections.|
|Brain tumour (15%)||It is not uncommon and on going back over the story of the time of onset can be less clear. Patients may bleed into tumours with sudden worsening.|
|Toxic-metabolic disorders, such as hyponatraemia and hypoglycemia (13%)||Always look for and treat hypoglycemia even in non-diabetic patients. Check U&E for other changes. One would expect a Na <120 mmol/L to cause neurological complaints. If above this look for other causes such as drugs, opiates.|
|Positional vertigo (6%)||Isolated vertigo is more likely to be vestibular. Especially if positional or brought on by head movements and is intermittent. Stroke-related vertigo is ongoing and usually accompanied by other brainstem signs.|
|Functional||Poorly understood. Very effortful attempts at movement. Tested together big difference in weakness but this is less clear when test each arm in turn. Can be very convincing. Need expert diagnosis. Needs negative MRI if unsure.|
|Migraine with unilateral motor weakness (MUMS)||Recently been described and has similarities with functional. Imaging is normal, signs are variable. My own experience is of stuttering speech and tingling tongues and paraesthesias being useful pointers towards a more migraine variant type diagnosis. Very poorly understood.|
Important for several respects. Important to define functional baseline pre-stroke abilities which will help target realistic therapy goals. One of the key proven benefits for thrombolysis is reducing functional independence and if a patient is already severely disabled and in a nursing home the benefits will be limited. A social history also is part of the holistic assessment in understanding the patient's life and personal preferences..
- Housing - flat, house, residential or nursing home
- Care - Independent, Daily or weekly carers
- Activities of Daily life
In practical clinical usage and research issues the modified Rankin is probably the most commonly used measurement of functional assessment and should be done pre and post stroke and over time.
|Pre Stroke Modified Rankin Scale|
|1||No significant disability. Able to carry out all usual activities, despite some symptoms|
|2||Slight disability. Able to look after own affairs without assistance, but unable to carry out all previous activities|
|3||Moderate disability. Requires some help, but able to walk unassisted.|
|4||Moderately severe disability. Unable to attend to own bodily needs without assistance, and unable to walk unassisted.|
|5||Severe disability. Requires constant nursing care and attention, bedridden, incontinent|
References and further reading
- Distinguishing Between Stroke and Mimic at the Bedside The Brain Attack Study, Peter J. Hand, Joseph Kwan, Richard I. Lindley, Martin S. Dennis, Joanna M. Wardlaw. Stroke. 2006;37:769-775
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