STROKE

#DEFINATION- cerebrovascular accident or stroke is defined as acute onset of neurological disorder of vascular aetiology.
Stroke may b-1.Haemorrhagic or 2.Ischaemic.

TYPES OF HAEMORRHAGIC STROKE.
1.Primasy intracerebral stroke.
2.Subarachnoid haemorrhage.
3.Prim intraventricular haemorrhage.

TYPES OF ISCHAEMIC STROKE.
1.Transient ischaemic attack.
2.Reversible ischaemic neurological deficit.
3.Complete stroke.
4.Lacunar infarcts.
5.Multifocal small infarcts leading to multi-infarct dementia.



PATHOPHYSIOLOGY.
The 2 main advances in stroke are delineation of ischaemic penumbra in ischaemic stroke and observation of haemotoma growth.

ISCHAEMIC STROKE.
-severity of stroke related to degree of impairment of cerebral bld flow nd the time to repurfusion.When bld flow is less than 10ml/100g/minute-neuronal cells die.
-ischemic penumbra:is a zone of moderately reduced cerebral bld flow between the ischaemic core and the normally purfused brain.
-within ischaemic penumbra,neurons r hypoxib,functionally inactive but still viable.Brain tissue undergo necrosis due to purfusion failure nd leads to secondary biochemical events like release of glutamate,influx of Na+ and Ca+ into cells,release of free-radicle species.

INTRACEREBRAL HAEMORRHAGE.
I.C.H ir a dynamic process nd substantial haematoma growth can occur in first 3 hour with most of growth in first 1 hour.Expansion is due to bleeding nd rebleeding.
Haemostatic theraphy in i.C.H would reduce volume of haematoma and result improved outcome.

RISK FACTOR FOR STROKE.
A.HIGH RISK
 1.Hypertension.
2.Diabetes mellitur.
3.Atrial fibrillation with or without valvular heart disease .
4.Smoking.
5.Vasculitis.

B.LOW RISK.
1.Migraine.
2.Oral contraceptives
3.Alcohol.
4.Patent foramen ovale.

ADDITIONAL RISK FACTOR IN YOUNG.
1.Protein c nd s deficiencies.
2.Antithrombin ||| deficiency.
3.Antiphospholipid syndrome.
4.Sickle cell anaemia.
5.Thrombotic thrombocytopenic purpura.

TRANSIENT ISCHAEMIC ATTACK.
DEFINATION.
-Abrupt onset focal neurological deficit of presumed vascular aetiology not lasting more than 24 hrs.
-most episode lasts for seconds to minutes.
-more recent defination of T.I.A is a brief episode of neurological dysfunction caused by focal brain or retinal ischaemia with clinical symptiom lasting less than one hour and without evidence of acute infarction.

MECHANISM.
Atherosclerotic plaque-->platelet thrombus get dislodge-->shortlasting obstruction-->breakdown of embolus-->reestablishment of perfusion-->clearance of neurological deficit.

SYMPTOM AND SIGNS.
-5 risk factors r related with a higher 3 month risk of recurrent stroke.=
1.Age >60 years.
2.Symptom duration >10min.
3.Weakness.
4.Speech impairment.
5.Diabetes mellitus.

CAROTID TERRITORY.
-ipsilateral mono ocular blindness-contra lateral hemiparesis.-hemianaesthesia.-dysarthria.-monoparesis-isolated facial weakness or sensory symptons of face or limbs .-reduced common carotid pulsation nd bruit over carotid artery in neck.-crystals of cholesterol in retinal vessels.

VERTEBRO-BASILOR TERRITORY.
-ataxia-hemianopia.-diplopia.-sudden fall-weakness on both sides-difficulty in swallowing -vertigo nd tinnitus r common.

INVESTIGATION.
ROUTINE TEST FOR STROKE.
1.Full blood count.
2.E.S.R.
3.Serological test for syphilis.
4.Blood glucose,urea,proteins.
5.Chest x ray.
IN YOUNGER PATIENTS.
1.Anti nuclear factor.
2.Cholesterol
3.Coagulation studies-antithrombin |||,protein S nd C.
ADDITIONAL TESTS.
A.IN VERTIBRO BASILAR TERRITORY.
1.Lying nd supine B.P.
2.24 hour E.C.G monotoring.
3.X ray cervical spine.
4.M.R.I angiography.

B.IN CAROTID T.I.As
1.C.T scan or M.R.I head.
2.Carotid doppler study.
3.Arteriography.

EVALUATION OF RISK FACTOR. Like
1.H.T.N
2.D.M.
3.Arterial disease affecting heart.Nd limbs.
4.Cardiac disease.
5.Smoking.

TREATMENT.
1.Correction of risk factor.-treat hypertension,diabetes.Correction of t valvular heart disease.,stop smoking.
2.Antiplate agents
-aspirin 300to 1200 mg/day.
-clopidogrel 75mg.
3.Anticoagulant.-if there is a Definite source of embolism.
4.Surgery -carotid andarterectomy,carotid stenting.

STROKE IN EVOLUTION.
In some patients,focal neurological deficit may worsen step wise over few hours or days.It is due to occlusion of major blood vessel by a thrombus.

WALLENBERG'S SYNDROME(LATERAL MEDULLARY SYNDROME)
It is due to infarct in dorsolaterl medulla nd occurs due to occlusion of posterior inferior cerebllar artery.Or parent vertebral artery itself.

IPSILATERAL SIGNS.
1.Pain,numbness nd impaired sensation over half the face.--descending tract nd nucleus of fifth nerve.
2.Ataxia of limbs,falling to side of lesion-cerebellum,olivocerebellar fibres.
3.Vertigo,nausea,vomiting,nystagmus,diplopia,.-vestibular nuclei.
4.Horners syndrome--descending sympathetic tract.
5.Dysphagia,hoarseness of voice,vocal cord paralysis,decreased gag reflex.-|X nd X nerves.
6.Loss of taste-nuclevs nd tractus solitarius.
7.Hiccup.
ON OPPOSITE SIDE.
1.Impaired pain nd thermal sense over half of the body --spinothalamic tract.
2.Hemiparesis.

MANAGEMENT OF STROKE OR CEREBRAL INFARCT(COMPLETE STROKE.)
Succesful care of acute stroke relies on four steps:-
1.Recognition nd reaction to worning signs.
2.Immediate use of emergency services.
3.Priority transport nd notification.
4.Rapid diagnosis nd intervention at hospital.

INITIAL EVALUATION.
1.Cardiovascular status.
-B.P
-Cardiac function.
-E.C.G
2.Degree of neurological deficit. And vascular territory involvement.
3.metabolic status.
-blood sugar.
-Presence or absence of hypoxia.
-Electrolyte status.
4.haematological parameters.
-Haemoglobin.

Monitor,
-neurological and cardiovascular status frequently in a day.
-Metabolic parameters.

OTHER INVESTIGATION,
1.C.T scan to confirm infarct and rule out haemorrage. Tumour and haematoma.
2.chest radiograph. As unconscious patient may get aspiration pneumonia.

TREATMENT,
1. General.
-Maintain airway and clear recreation, chest physiotheraphy.
-Skin care by changing position to prevent bed sore.
-Nasogastric tube to maintain adequate hydration or to prevent vomiting.
-Bladder care by catherisation.

2.SPECIFIC MEASURES.
-Blood pressure :-rapid reduction in blood pressure may increase size of infarct, hence it is gradually reduced over days.
-Anti edema measures: - by 1.mannitol 20% I. V over 20 min three or four times a day.
2. Glyserol 30 ml orally three times a day.
-Maintain blood sugar level.
-Avoid raise in body temperature.
-avoid hypoxia.

 ANTICOAGULANTS.
Anticoagulants like heparin are indicated in following.
-Recent myocardial infarction where they r used for 3 month.
-previous myocardial infarction with ventricular aneurysm.
-presence of artificial valve.
-progressive stroke.

THROMBOLYTIC THERAPHY.
Recombinant tissue plasminogen activator is useful within first 3 hour in ischaemic stroke in patient above 18 years.
CONTRA INDICATION.
1. Blood on C.T SCAN.
2.active internal bleeding.
3.Systolic pressure >185 mm of hg, diastolic >110 mm of hg.
4. History of intra cranial bleeding.

DOSE-0.9 mg /kg with 10% of total dose as bolus nd rest over 1 hour.