Stroke is defined as the rapid loss of brain
functions due to disturbances in the blood supply to the brain. Due to lack of
oxygen and glucose death of brain tissue occurs. It is also known as
cerebrovascular accident.
Stroke is a serious medical emergency resulting in
permanent damage to the brain. The risk factors of stroke are diabetes,
hypertension, old age, cigarette smoking, atrial fibrillation, high cholesterol
level, high alcohol intake, previous stroke history and family history.
Broadly stroke can be of two types-ischemic or
hemorrhagic. Ischemic type is more common than the hemorrhagic one and accounts
for about
85
percent to
87 percent of stroke cases.
When the artery supplying the brain is blocked,
ischemic stroke occurs. Thrombotic stroke is the condition where a blood clot
is formed in the vessels and reduces the supply of blood to the brain.
Hemorrhagic stroke occurs when the blood vessels supplying blood to the brain
ruptures. The blood clots and damages the brain tissues.
Causes of Ischemic Stroke:
There are four main causes of ischemic stroke. They
are as under:
• Embolism- obstruction caused by embolism
• Thrombosis- Obstruction caused by a blood clot that hampers
the blood flow in an artery
• Venous Thrombosis- It is a rare cause of ischemic stroke where blood
clot obstructs the dural venous sinus draining blood from the brain.
• Systemic Hypoperfusion- Generalized reduction in blood
supply as in shock
Cryptogenic Strokes- When there is no obvious
known cause of stroke, it is termed as cryptogenic strokes or strokes with
unknown origin. About 30 percent to 40 percent of ischemic strokes are
cryptogenic type.
On the basis of location of bleeding, haemorrhagic
strokes are of two types:
1. Extra-axial Hemorrhagic- the blood vessels is ruptured
between the brain and the skull. Main types of extra-axial hemorrhages are:
• Epidural hematoma (hemorrhge between the dura mater and the skull)
• Subdural hematoma (Bleeding in the dural space)
• Subarachnoid Hemorrhagic (Bleeding between the arachnoid
space and pia mater)
2. Intra-axial Hemorrhagic - blood vessels within the brain
ruptures. This can be
• Intraparenchymal Haemorrhage
• Intraventricular Haemorrhage (Presence of blood clot in the
ventricular system)
Signs and Symptoms:
The common clinical manifestations of stroke are as
under:
Numbness and weakness of face, legs and arms,
difficulty in speaking or comprehending speech, confusion, loss of balance,
dizziness, vomiting, severe headache, difficulty in walking, hemiplegis,
muscular weakness of face, altered vision, smell and taste, ptosis- drooping of
eyelids, weakness of muscles of eye, reduction in reflexes such as gag, pupil
reactivity to light and swallow, nystagmus, difficulty in maintaining balance,
weakness of sternocleidomastoid muscles, difficulty in turning head, inability
to protrude tongue out and move sidewards, vertigo.
The acronym
F.A.S.T. is very helpful in determining
whether a person is experiencing a stroke or not.
• Face: Ask the person to smile
• Arm: Ask him to lift both the arms
• Speech: Ask the person to repeat a sentence or phrase
• Time: Call medical emergency in case the person has the above
mentioned symptoms.
Pharmacological Treatment:
Depending upon the type of stroke the pharmacologic
treatment varies.
For ischemic stroke tissue plasminogen activator
(tPA) and antiplatelets agents are used and the treatment of hemorrhagic stroke
is based on controlling the intracranial pressure and blood pressure.
Treatment of Ischemic Stroke:
tPA: The most preferred IV tPA agent is alteplase. It has been
approved by FDA for its efficacy in treating ischemic stroke.
Antiplatelets Agents: The most authentic drug for the treatment of
ischemic stroke is aspirin. Within 24 to 48 hours of stroke aspirin therapy
should begin. Ticlopidine is known to produce aspirin- like effects.
Oral warfarin and infusions of heparin can also be
given.
Osmotic agents such as intravenous mannitol 20% and
potent sterods like dexamethasone 4 mg intravenous is given to control cerebral
oedema.
Secondary Prevention of Ischemic Stroke:
Secondary management of ischemic stroke is important
and involves the following points:
• Controlling blood pressure
• Controlling cholesterol levels, particularly
lowering LDL levels Statins are effective in lowering cholesterol levels.
Fibrates and niacin are also helpful in controlling triglyceride levels.
Treatment of Hemorrhagic Stroke:
The annual incidence rate of hemorrhagic stroke is
about 15 percent. The pharmacologic treatment of hemorrhagic stroke is quite
limited, however following steps:
• Find out the cause of bleeding
• Control blood pressure
• Discontinue any medication that might cause
further bleeding
• Take steps to control intracranial pressure.
Ventriculostomy can be done to remove collected blood from the brain.
Decompressive craniotomy can also be done.
Since subarachnoid hemorrhages
are caused mainly by aneurysm, therefore surgery the treatment of choice.
Secondary Prevention of Intracerberal Hemorrhagic Stroke:
The predisposing factors of recurrence of
intracerebral hemorrhagic stroke are:
• Old age
• Anticoagulation therapy post intracerebral
hemorrhage
• Location of previous hemorrhage
Finally, it can be concluded that
stroke is a time-sensitive condition irrespective of its type. Though the
pharmcotherapeutic choices are limited, but they are effective in mitigating
both the complications involved and the recurrence of the stroke.
Reference:
1.Pharmacologic Management of Stroke - Shari N. Allen, assistant professor of Pharmacy Practice
in Philadelphia College of Osteopathic Medicine School of Pharmacy, Georgia; US Pharmacist 2012.
Source-Medindia
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