A systematic Medline search of the medical literature was performed
in January 2008 using Ovid. Subject headings included Cerebrovascular
Accident/Prevention and Control, Drug Therapy, Surgery,
Stroke is a common diagnosis in primary care and it is the third
leading cause of death in Americans. Primary care clinicians provide
stroke care to three main groups of patients: (1) patients at high
risk of stroke requiring primary prevention, (2) patients with a
history of stroke requiring secondary prevention, or (3) patients
with signs and symptoms consistent with acute stroke, requiring
urgent care. The purpose of this chapter is to review the risk factors,
the clinical presentation and diagnosis of stroke and the recommended
approach to acute treatment and prevention.
Stroke can be either ischemic or hemorrhagic. Ischemic stroke
is the most common, representing 87% of the more than 700,000
strokes reported in the United States.1 The classification
of stroke is illustrated in Fig. 16-1. Understanding the etiopathogenesis
of the stroke is paramount in determining the correct treatment,
intervention and/or prevention strategies.
Classification of stroke. The types of stroke are illustrated,
showing their location and prevalence.
The presentation and etiologies of ischemic stroke vary based
on the vessels affected. Atherosclerosis of large, medium, and small
arteries can result in ischemic stroke. Aortic, carotid, and vertebral
artery plaque can be a source of emboli to the brain leading to
stroke. Atherosclerosis can cause stenosis and impede further blood
flow. Lipohyalinosis usually affects the small penetrating arteries
and accounts for lacunar (small, deep) infarcts. Cardiac diseases
such as atrial fibrillation (which predisposes to embolic phenomenon),
acute myocardial infarction, cardiomypopathy, and valvular disease
are a few of the many conditions that can predispose to a stroke.
Hypotension can cause borderzone infarcts in different vascular
territories. Other causes such as hypercoagulable states, vasculitis,
and dissections also should be sought. In spite of an exhaustive
work up, at times the etiology or cause of the stroke remains elusive.
These cryptogenic strokes account for 30% of ischemic strokes.
Hemorrhagic strokes are most commonly caused by uncontrolled
hypertension and usually affect penetrating arteries in the putamen,
thalamus, pons, and cerebellum. Amyloid angiopathy in the elderly
is another cause of hemorrhagic stroke and is often responsible
for hemorrhages in the parietal or occipital lobes. Hemorrhage in
a young patient without the history of hypertension should raise
suspicion of other causes such as drug abuse (e.g., cocaine, amphetamines,
methylphenidate, etc.), arteriovenous malformations, and brain tumors.
Medications such as thrombolytic therapy (e.g., tissue plasminogen
activator [tPA]), or anticoagulants (e.g., warfarin)
are also associated with the development of hemorrhagic stroke.
Hemorrhagic transformation of an ischemic stroke is seen most often
in embolic strokes, large infarcts, middle cerebral artery stem occlusion,
and also in the setting of uncontrolled hypertension and early use