OBJECTIVES

1. Understand that the most common cause of neurologic disease is vascular disease involving the cerebral circulation.

2. Briefly describe and differentiate between transient ischemic attack (TIA) and the types of ischemic stroke (thrombic and embolic) and hemorrhagic stroke (hypertensive and subarachnoid)  with respect to cause, signs and symptoms, short and long term effects. (pp. 827-834)

3. Define and briefly describe each of the following: cerebral atherosclerosis, cerebral thrombosis, cerebral embolism, intra-cerebral hemorrhage, subarachnoid hemorrhage, encephalitis and meningitis. (pp. 829, 833, 858)

4. Know and briefly describe the 5 main causes of prolonged increased intracranial pressure (IIP): hemorrhage (epidural and subdural), blockage of CSF passage (hydrocephalus), blockage of venous drainage, inflammation (including swelling of brain cells and edema), and intracranial neoplasms.

5. Briefly describe and distinguish between subdural and epidural hematomas with respect to cause, signs and symptoms, effects and treatment. (pp. 872-876)

6. Briefly describe the most common types of intracranial neoplasms (meningioma, glioma). (pp. 881-882)

7. Know all underlined terms and * questions, including * case study questions.

Brain with Cerebral Atherosclerosis (if available) Fig. 7-8, (p. 102), Figs. 53-2, 53-3, (pp. 825-826)

Observe the arteries on the inferior surface of this brain. These are the major arteries supplying blood to the brain and include the Circle of Willis and its branches. In this specimen, many of these arteries contain atherosclerotic plaques (observe the sites which have been opened). (The discoloration of this brain is due to fixation).

        These images show the development of atherosclerosis, which is the main cause of cerebrovascular disease. The processes shown in these images of coronary arteries and the aorta also occur in the carotid arteries going to the brain and in arteries within in the brain. Affected arteries become narrow, rough, stiff and weak.
        Normal coronary artery, microscopic *
        Mild coronary atherosclerosis, microscopic *
        Severe calcific coronary atherosclerosis, microscopic *
        Aorta, lipid streaks, gross
        Aorta, lipid streaks, gross
        Aortas with mild, moderate, and severe atherosclerosis, gross
        Aorta, atheromatous plaque, medium power microscopic *
        Aorta, atheromatous plaque, high power microscopic *
        Aorta, atheromatous plaque, high power microscopic *
        Aorta, atherosclerotic aneurysm, gross

* What potential complications could occur as a result of these plaques?

Old Cystic Infarct - Human Brain Section (Fig. 3-6, p. 37)

       31. Cerebrum, coronal section, acute cerebral infarct, gross
        This image shows infarction from ischemia.
        38. Cerebrum, coronal section, hemorrhagic infarct, from arterial embolus, gross
        This image shows infarction from ischemia. There is also slight hemorrhaging from the necrotic region.
        37. Cerebrum, coronal section, hemorrhagic infarct, from arterial embolus, gross
        This image shows infarction from ischemia followed by significant hemorrhaging in the necrotic region. Note the     development of edema from the inflammatory response.
        39. Cerebrum, acute infarction, microscopic *
        This image shows infarction from ischemia and the development of edema from the inflammatory response.
        42. Cerebrum, coronal section, subacute infarct with edema and midline shift.
        This image shows infarction from ischemia. Note the effects from inflammation and edema.
        Liquefactive necrosis, cerebral infarction, gross
        This image and the next seven images show the liquefaction of infarcted brain regions.
        Liquefactive necrosis, cerebral infarction, gross
        Liquefactive necrosis, cerebral infarction, microscopic *
        44. Cerebrum, remote infarct, microscopic *
        Liquefactive necrosis, cerebral infarction, microscopic *
        29. Pons, lacunar infarct, gross
        30. Lacunar infarct, microscopic *
        45. Cerebrum, coronal section, remote infarct, gross

Look closely at this frontal section of human brain. Can you find the area where infarction has occurred?

* What would have been a likely cause of this infarction?

Do you think this patient suffered a TIA, an RIND or a completed stroke?

The patient survived for a number of months after the stroke.

* What occurred in the infarcted area during this time? (i.e. What type of necrosis occurred in this area? ) (p. 37)

Subdural Hematoma (pp. 874-875)

        6. Bridging veins from dura, gross
        5. Subdural hematoma, acute, gross [CT]
        7. Subdural hematoma, bilateral, chronic, gross [CT]
        59. Infected subdural hematoma, gross
        4. Epidural hematoma, gross [CT]

Notice the tough white membrane, the dura mater, which normally covers the brain and the massive hematoma produced from bleeding of the subdural veins.

* What is a common cause of subdural hematomas?

* How do they cause neurological defects?

This X-ray shows the cerebral vasculature highlighted by the injection of radiopaque dye via the carotid artery. Note the branching of the common carotid artery at the superior end of the neck into the internal and external carotids and then into numerous smaller vessels.

* What kinds of information can be gained from cerebral angiograms? (p. 835)

CT Scans (pp. 439-440)

In CT (computerized tomography) scans, the X-ray source moves in a circle around the patient sending a narrow beam of X-rays through the patient. These beams then reach a receiver (directly opposite the source) which sends the information to the computer. The computer processes this information to create a cross-sectional picture of the region scanned. Numerous cross-sections can be made of any area of the body. Because this technique is much more sensitive than conventional X-rays, important information can be obtained regarding internal areas (including the cranial cavity) without using more invasive techniques.

Examine the various CT scans and see whether you can find the abnormality in each case (some are more obvious than others).

MRI Scans (pp. 440-441)

MRI stands for Magnetic Resonance Imaging. MRI scans look much like CT scans but they are produced using magnetic fields rather than ionizing radiation.

Examine the MRI scans in lab; these were all obtained from a single patient and include frontal and sagittal sections as well as cross-sections.

Cerebral Arteriosclerosis

Compare the sulci and gyri in the upper region of the cerebral hemisphere with those in the lower region. Because of chronic ischemia caused by atherosclerosis in the cerebral arteries, neurons have atrophied. This results in the shrunken gyri and enlarged sulci in the upper region. Functionally, cerebral activity is reduced resulting in senility.

        Atrophy, cerebrum, gross

Name 3 other ways by which cerebral atherosclerosis leads to brain disorders.

Fracture of Skull

In this case of head trauma, jagged bone fragments have resulted from fracture of the skull. Notice the blood clot in the area which, as it enlarges, will cause increased intracranial pressure. The sharp bone fragments could also cut into meningeal arteries or veins leading to additional hemorrhaging. Finally, note how the brain is compressed at the fracture site.

        Skull fracture, base, orbital plate, gross 
        Skull fractures, cranial vault, gross 

* Why would cutting of arteries be more serious than cutting of veins?

Fracture of Vertebrae, Contusion of Spinal Cord and Metastatic Tumor in Vertebrae (pp. 876-878)

These diagrams show how increased pressure from alteration in alignment can cause spinal cord injury. The nerve tissue of the cord, being very soft, is easily injured. Bleeding and swelling resulting from inflammation increase the pressure. The specific neurologic deficits which result depend upon the level of the cord involved and the specific cord tracts affected.

        Vertebrae, compressed fracture, gross 
        Vertebrae, metastatic carcinoma, gross [MRI] 
        Vertebrae, metastatic carcinoma, gross [XRAY] 

Herniation of Intervertebral Disc (pp. 816-819)

In a herniated (or slipped) intervertebral disc, the jelly-like center (the nucleus pulposus) ruptures through the fibrous capsule. Notice how the ruptured disc is pressing on a spinal nerve, which can cause severe back pain. This is one of the most common causes of back pain. It often occurs later in life because the fibrous capsule dries out and becomes more brittle with age. (Be sure to see the model of the herniated disc).

* What treatments are commonly used for a herniated disc? (pp. 816-819)

CASE 1
Go to Images of Strokes
Keith McF. is a seventy-one year-old white male brought to the out-patient clinic by his daughter in a confused but ambulatory state. She related that over the past several weeks her father had stumbled and perhaps fallen several times, though apparently without hurting himself. He has occasionally failed to respond in conversation, and had dropped eating utensils and his pipe while using them. That morning when she went to wake him, he was confused, his speech was slurred, and he was unable to stand. Subsequently, his confusion cleared, and he became able to walk with help. Past history included a diagnosis eight years previously of mild adult diabetes mellitus treated with diet. Only general preventative and supportive therapy was given. On a follow up visit in the clinic two weeks later, Mr. McF. had no recurrence of symptoms.

CASE 2
Go to Images of Strokes
Armando S. is a 41 year-old bank vice-president brought to the emergency room by co-workers in mid-afternoon because of a sudden and rapidly worsening paralysis of his right arm and hand, slurring of speech followed by an inability to speak. The patient was reported to be in generally good health, although he had suffered a mild myocardial infarction about two years previously. Armando, refusing surgery, was admitted to the Neurology Service where his speech improved considerably over the first two weeks, but his paralysis remained basically unchanged. He is undergoing physical therapy.

CASE 3
Go to Images of Strokes
Maria G. was a 38 year-old Spanish American woman brought in by ambulance to the emergency room in a semi-comatose state. Her husband reported that she had appeared well on returning from grocery shopping and picking up children from school, but complained of a severe headache which interrupted her preparation of dinner. A few minutes later she vomited once, then collapsed in a confused and only partially responsive condition. During examination in the emergency room, she initially responded to arousal, but rapidly became comatose with a loss of pupillary and tendon reflexes. An endotracheal tube was inserted. Vital signs included temperature 36.8C, pulse 88, respirations 12, blood pressure 142/118. Spontaneous respirations stopped and the patient was placed on a respirator and EKG monitor. While arrangements were being made to transport the patient to the local hospital, cardiac arrhythmias developed, followed by cardiac arrest which was refractory to resuscitative efforts. The patient was pronounced dead approximately two and one half hours after the onset of symptoms. A lumbar puncture performed post-mortem returned grossly bloody spinal fluid.

Discussion Questions:

1. What are the United States Mortality and Morbidity statistics in relation to C.V.A.'s? (pp. 822-823)

*2. What are the four most common causes of strokes? (p. 827)

*3. Name and describe the two types (causes) of ischemic stroke and the two types (causes) of hemorrhagic strokes. (pp. 828-829, 833-834)

*4. What risk factors increase the possibility of developing a stroke? (pp. 823,834)

*5. Identify the risk factors in the three cases.

*6. What are the most common signs and symptoms of stroke? (p. 831)

*7. Name the type of cerebral vascular disease that Keith experienced and the likely cause. What led you to this conclusion? Although he was not experiencing symptoms on his follow-up visit, why is it crucial that he have a full medical and neurological work-up? (pp. 826-834)

*8. Name the type of cerebral vascular disease that Armando experienced and the likely cause. What led you to this conclusion? Although it is always important, why is it especially important to monitor Armando during the days immediately following the event? (pp. 826-834)

*9. Name the type of cerebral vascular disease that Maria experienced and the likely cause. What led you to this conclusion? (pp. 826-834)

*10. What imaging techniques and diagnostic tools aid in the evaluation of a stroke patient? What information can they provide? (p. 835)

*11. Name the 3 goals of emergency treatment of stroke and the 3 therapies that are effective after ischemic strokes. (p. 836)

*12. Why is it crucial for clinicians to determine ASAP whether the stroke is an ischemic stroke or a hemorrhagic stroke? (pp. 832, 836)

8Copyright 2001 - Augustine G. DiGiovanna - All rights reserved.

This material may not be reproduced or distributed in any form or by any means, or stored in any data base or retrieval system without prior written permission is obtained from Augustine G. DiGiovanna, Ph.D.,  Professor of Biology, Salisbury University, Salisbury, MD  21801.