CVA UMST

CNS Pathology: Cerebrovascular Accident (CVA)

• CVA, also known as stroke or cerebrovascular disease (CVD), is an acute neurological deficit resulting from vascular insult. The insult can be from thrombosis, embolism, or hemorrhage.
• Stroke is associated with reduced blood supply (hypoxia).
• CNS infarction is cell death due to ischemic injury in the central nervous system (CNS), identified through imaging, neuropathology, or clinical assessments.

Classifications

• Transient, evolving, and completed ischemic or hemorrhagic CVA.
• Focal or global.
• Arterial or venous.
• Varying severity based on location and type.

Epidemiology

• Stroke is the second leading cause of neurological disability after Alzheimer's disease.
• Globally, there are approximately 12 million strokes annually, resulting in roughly 4 million deaths.
• Globally, stroke is the third leading cause of death.

Risk Factors

• Non-modifiable: Age, male sex, race, heredity.
• Modifiable: Hypertension (HT), diabetes mellitus (DM), smoking, hyperlipidemia, excess alcohol, cardiac diseases (e.g., atrial fibrillation), oral contraceptives, hypercoagulability states, diet/sedentary lifestyle/stress.

Sites

• Ischemic stroke can affect any site in the CNS.
• The middle cerebral artery (MCA) is frequently affected in ischemic stroke.
• Possible causes of MCA damage include thromboembolism (e.g., internal carotid atherosclerotic plaque, atrial fibrillation).

Pathophysiology

• Decreased blood flow leads to liquefactive necrosis.
• Increased intracranial pressure (ICP) results from edema or hemorrhage, causing herniation.

Etiology

• Most common causes of stroke include atherosclerosis, cardiac pathology, and hypertension.
• Other less common causes include vasculitis, coagulation disorders, arterial dissection, reversible vasoconstriction syndrome, HIV-associated arteriopathy, Moyamoya disease, and fat embolism (especially in preterm/low-birth-weight infants).

Clinical Features

• Symptoms vary depending on the affected region. Common symptoms include contralateral hemiparesis (unilateral weakness of upper and lower limbs), hemianesthesia (absence of unilateral sensations), and aphasia (inability to understand or express oral language). Symptoms differ for left-hemisphere and right-hemisphere strokes.

Gross Description

• Acute infarct (1-4 days): Neurons are more susceptible to ischemia than glia; necrosis with neutrophilia.
• Subacute (5-14 days): More necrosis and more macrophages.
• Chronic (15+ days): Cavitated lesion with vessels and macrophages surrounded by glial scar tissue.

Macro & Microscopic Description

• Infarct morphology varies with time post-onset.
• Acute: Blurring of gray-white matter junction, edema, red neurons.
• Subacute: Cracking artifact, dense macrophage infiltration, neovascularization.
• Chronic: Cavitated lesions, macrophages, gliosis.

Diagnosis

• Clinical: Physicians initially make a diagnosis based on clinical examination.
• Imaging: CT, CT angiography, MRI, PET, ECG, and CX-rays aid in the diagnosis.
• Laboratory: CBC, platelet count, and coagulation tests (aPTT, PT, TT) rule out coagulopathies (important for thrombolysis contraindications). Blood glucose, electrolytes, liver function tests (LFT), and renal function tests (RFT).

Treatment

• Acute ischemic stroke (within 6-8 hours of onset): Systemic thrombolysis or thrombectomy.

Prognostic Factors

• Age at presentation.
• Degree of neurologic impairment.
• Infarct volume and location.

Intracranial Hemorrhages

• Intracranial hemorrhage (ICH) involves bleeding within the skull.
• Types include intracerebral (intraventricular and intraparenchymal), subarachnoid, epidural, and subdural.

Epidural Hemorrhage

• Typically results from trauma, primarily temporal bone fractures causing middle meningeal artery rupture.

Subdural Hemorrhage

• Often associated with trauma, but also with cerebral atrophy in the elderly, and systemic cancer or CNS tumors.

Subarachnoid Hemorrhage

• Most frequently caused by rupture of saccular aneurysms.
• Other potential causes include vascular malformations, trauma, hematological disturbances, and tumors.

Hemorrhage into Brain Parenchyma

• Massive hemorrhage displaces brain tissue; smaller hemorrhages can be subacute or chronic. Common causes include hypertension, arteriovenous malformations (AVMs), and ruptured aneurysms.

Causes of Intracranial Hemorrhage

• Trauma is the most common cause.
• Non-traumatic causes: Hypertension, cerebral amyloid angiopathy, hemorrhagic conversion of ischemic infarct, cerebral aneurysms, dural arteriovenous fistulae, cerebral venous sinus thrombosis, cerebral vasculitis, and mycotic aneurysm.

Complications of Intracranial Hemorrhage

• Coma.
• Persistent vegetative state.
• Cardiac arrest.
• Death.

This quiz covers the key elements of cerebrovascular accidents (CVA), including types, classifications, and epidemiology. Understand the risk factors and learn how strokes are identified and assessed in the context of central nervous system pathology. Test your knowledge on this critical topic in neurological health.