Neuropathology

In reference to traumatic brain injury, provide a description of (a) a "coup" injury and (b) a "contre-coup" injury

A "coup" injury describes an injury that is sustained from the initial impact of the skull with a foreign object A "contre-coup" injury is an injury resulting from the backlash or whiplash created by the force that caused the initial coup injury and is usually on the opposite side from the initial injury

Berry (saccular) aneurysm

A berry aneurysm looks like a berry shaped pod attached to the side or at the bifurcation (splitting) of an artery, with a well-defined "stalk" allowing blood to flow in and out of the "berry". A saccular broad-based berry aneurysm lacks the defined "stalk" and has a much wider "berry"

Coma

A coma describes a patient who has no verbal response to the external environment or any stimuli. More intrusive stimuli such as intense pain or suctioning may yield some motor movement

Discuss the use of flow diverting stents to treat large aneurysms

A flow diverting stent is a less invasive option especially for intracranial aneurysms that involves guiding the platinum coil through the circulatory system to the aneurysm which is then detached and left inside. This stimulates blood clotting inside the aneurysm and has a similar effect to the metal coils strategy in that it reduces the blood flow into the berry of the aneurysm therefore reducing the pressure and reducing the chances of it rupturing

Fusiform Aneurysm

A fusiform aneurysm is when a section of the let him vessel wall stretches and creates a balloon that all the blood in the vessel flows through

Describe, in general, the procedure of using a blood clot retriever

A guiding catheter is inserted into the blood vessel which advances past the clot, and then expands to create a cage or net which will grab the blood clot on its way back out, allowing the blood clot to be removed

Light Coma

A light coma is a coma where a patient still demonstrates purposeful movement upon stimulation

Most cranial nerve reflexes rely on an intact brainstem to integrate the incoming (afferent) sensory signal onto the outgoing (efferent) motor signal. Also, these same regions of the brainstem contain nuclei that maintain respiratory rate, heart rate, and blood pressure. (a) Use this information to discuss why a neurologist might stimulate cranial nerve reflexes in an unconscious person with recent head trauma. (b) Include the test of at least one cranial nerve reflex in your discussion

A neurologist may stimulate the cranial nerve reflexes in an unconscious patient with recent head trauma in an effort to assess the functioning of the patient's brain stem. This is an important metric as it gives the Physician information about how dire the prognosis of the patient is and whether swift and invasive interventions are necessary to sustain the patient's life Two cranial nerve reflexes the Physician may test include the oculovestibular reflex and the pupillary reflex

Deep Coma

A patient in a deep coma will be completely unresponsive to any and all sources of stimuli regardless of intensity

Subdural hematoma

A subdural hematoma is when an artery or vein is damaged that causes bleeding underneath the dura mater. This can lead to a similar increase in intracranial pressure as an epidural hematoma and is equally capable of suppressing the vital centers of life. An acute subdural hematoma is usually caused by a ruptured artery and results in rapid buildup of blood just outside of the cerebral cortex, this is usually a life-threatening condition and may require emergency surgery to remove the blood until the source the bleeding can be identified. Chronic subdural hematoma would-be bleeding within the dura mater but at a much slower rate causing it to slowly build up over time and significantly delaying the onset of acute symptoms of increased intracranial pressure

Describe the physiological consequence of losing the oculovestibular reflex

The consequences of losing the oculovestibular reflex are similar to those of losing the oculocephalic reflex in that both reflexes are used to assess the potential for damage or dysfunction in the brainstem

Cingulate Herniation

Cingulate herniation is the most common type of herniation and the brain, it occurs when one hemisphere swells and pushes the cingulate gyrus this past the falx cerebri. This type of herniation is less dangerous than most because it does not put any extra pressure on the brainstem

Confusion

Confusion is the loss of ability to think rapidly and clearly, impairing judgment and decision-making

Describe why decorticate rigidity receives a higher number (+3) compared to decerebrate rigidity that receives a lower number (+2) on the Glasgow Coma Scale. (hint-relate the relative location of the lesion within the brain to the brainstem containing vital centers of life

Decorticate rigidity receives a higher number compared to decerebrate rigidity that receives a lower number on the Glasgow coma scale because of the location of the likely tissue damage within the brain. Decorticate rigidity implies that any brain lesions or tissue damage occurred above the midbrain and do not involve the brainstem. Decerebrate rigidity suggests there may be severe damage in the midbrain and possibly including the brainstem. Decerebrate rigidity gets the lower score of two because damage within the brain stem is far more dangerous to a person's survival as this is the area that controls the vital functions for life such as breathing, regulation of heartbeat, blood pressure, etc

Epidural hematoma

Epidural hematoma is most commonly caused by trauma to the side of the head which can cause the middle meningeal artery to rupture. Epidural means on top of the dura mater. When a hematoma is the result of a ruptured artery this causes a large volume of blood to collect in the epidural space quickly resulting in a rapid increase in intracranial pressure which can then place pressure on the brainstem and threaten the vital functions of life

Describe the relative prognosis for a person in coma that has lost the corneal blink reflex and the pupillary light reflex. (refer to information in "The Prognosis of Medical Coma" article discussed in recorded lecture.)

For a patient in a coma that has lost the corneal blink reflex and the pupillary light reflex their prognosis of recovery is close to 0%. In the article discussed during lecture none of the patients that while missing either of these two reflexes survived

Describe how to perform the normal oculocephalic reflex

Instruct patient to focus eyes on a distant object (or place one squarely in their view) and then manually tilt their head and left and then write, if their eyes are able to stay focused on the object in the distance this is a positive outcome for the oculocephalic reflex. If their eyes are not able to focus on the object and instead remain looking directly forward, they lack the oculocephalic reflex

Intracerebral hemorrhage

Intracerebral hematoma is usually caused by penetrating head injury or blunt trauma to the skull and refers to the formation of the hematoma within the brain tissue itself. This type of injury can also increase intracranial pressure to the point it becomes life-threatening and may have other more immediate consequences on brain function depending on the location of the hematoma within the brain

Describe the physiological consequence of losing the oculocephalic reflex

Loss of the oculocephalic reflex indicates depression (pressure, dysfunction) within the brain stem and indicates an increased risk of death in the patient due to mis regulation of the vital processes of life

Discuss the use of metal coils to treat berry aneurysms

Metal coils can be used to treat berry aneurysms by cutting off blood flow through the stalk, therefore reducing the pressure in the aneurysm and reducing the chances that it will rupture

Mild Impairment GCS

Mild impairment refers to a patient who is only slightly impaired and refers to someone who has a Glasgow coma scale score of 13 to 14

Moderate Impairment GCS

Moderate impairment describes a patient who is more severely impaired and has a Glasgow coma scale score of 9 to 12

How does the textbook define "full consciousness"?

The book defines full consciousness as a state of awareness both of oneself and of the environment and a set of responses to that environment

Severe Impairment GCS

Severe impairment is the most extreme score someone can get and refers to a Glasgow coma scale score of 3 to 8. A score of three would be a patient who is completely unresponsive to any and all stimuli, essentially in a coma

Provide descriptions of various signs associated with increased intracranial pressure (ICP)

Some signs and symptoms associated with increased intracranial pressure include changes in level of consciousness, headache, vomiting, seizures, motor and sensory changes or Cushing's triad. Cushing's triad is a combination of three different changes in a patient's vital signs, it refers to a decrease in heart rate (bradycardia), widened pulse pressure (difference between diastolic/systolic), and slow deep respirations. You may also see changes in cranial nerve reflexes (oculocephalic, oculovestibular, pupillary, corneal, gag), which indicate dysfunction in the brainstem

Stupor

Stupor is a condition of deep sleep or unresponsiveness; the person may be aroused or cause to open their eyes only by a vigorous and repeated stimulation. The response received from this is often a withdrawal reflex or a grabbing motion at the source of the stimulus

Middle Cerebral Artery

Supplies blood to lateral aspect of brain hemispheres. These regions code for upper extremity motor control and sensory input

Anterior Cerebral Artery

Supplies blood to the medial aspect of the brain hemispheres, the precentral gyrus (motor cortex) and postcentral gyrus (somatic sensory cortex) in this region innervate motor control and receive sensory input from the lower extremeties

Describe the pathophysiology of a stroke involving the anterior cerebral artery. In your discussion, (a) review the normal vascular territory of the anterior cerebral artery, (b) describe the normal body regions somatotopically mapped to that area of cerebral cortex, and (c) describe consequences of occluding an anterior cerebral artery

The anterior cerebral artery supplies blood to the medial aspect the brain hemispheres The medial region of the precentral (motor cortex) and postcentral gyri (somatic sensory cortex) is responsible for contralateral movement and sensation of the lower extremities Occluding a portion of the anterior cerebral artery that supplies blood to the precentral gyrus (motor cortex) and postcentral gyrus (somatic sensory cortex) may cause contralateral hemiplegia in the lower extremities (loss of motor function) as well as loss of sensation in the lower extremities if the postcentral gyrus is affected as well

Describe the anatomical location of the medial longitudinal fasciculus specifically identifying how it connects vestibular function to eye movements

The medial longitudinal fasiculus is a nerve running up the center of the brainstem and is responsible for relaying sensory information to the motor cortex (ie, translating sensory information into motor reflexes). If it is damaged, then the sensory information responsible for producing eye movement in the oculovestibular reflex would not reach the motor cortex, and no eye movement is produced

Describe the pathophysiology of a stroke involving the middle cerebral artery. In your discussion, (a) review the normal vascular territory of the middle cerebral artery, (b) describe the normal body regions somatotopically mapped to that area of cerebral cortex, and (c) describe consequences of occluding a middle cerebral artery

The middle cerebral artery supplies blood to the lateral aspects of the brain hemispheres The lateral aspect of the brain hemispheres are primarily responsible for upper extremity motor control and sensory input The consequences of occlusion or hemorrhage of the middle cerebral artery include contralateral hemiplegia and loss of sensation, as well as rigidity and tremor if the basal ganglia are affected (due to occlusion of striatal branches of the middle cerebral artery, similar symptoms to Parkinson's but with sudden unilateral onset)

Describe how to perform the normal oculovestibular reflex

The oculovestibular reflex can be measured by introducing hot or cold water into the ear of a patient and seeing if their eyes move in the direction of the stimulus

Describe the pathophysiology of a stroke involving the posterior cerebral artery. In your discussion, (a) review the normal vascular territory of the posterior cerebral artery, (b) describe the normal body regions somatotopically mapped to that area of cerebral cortex, and (c) describe consequences of occluding a posterior cerebral artery

The posterior cerebral artery supplies blood to the posterior region of the brain including the occipital lobe and the inferior portions of the temporal lobes The occipital lobe supplied by the posterior cerebral artery is responsible for vision If the blood flow to the occipital lobe is halted, one possible symptom is visual agnosia in which the patient can still see but is unable to identify objects. A patient who has a stroke affecting only one of the occipital lobe hemispheres may experience homonymous hemianopsia, which is a condition in which ½ of the visual field of each eye is lost. The term homonymous indicates that it is the same half of the visual field that is lost in each eye, and the term hemianopsia indicates that only ½ visual field has been lost

Types of Stroke (Ischemic, Thrombotic, Embolic, Hemorrhagic)

There are two main types of stroke both referring to the cessation of blood flow in a cerebral blood vessel. Ischemic stroke is caused by a blood clot physically blocking the flow of blood in a blood vessel. There are two types of ischemic stroke, thrombotic stroke refers to a locally formed blood clot in a cerebral blood vessel that occludes blood flow (thrombus), while an embolic stroke is similar but instead the cerebral blood vessel is blocked by an embolus, which is a blood clot formed elsewhere in the body that has broken off and traveled to the brain. Hemorrhagic stroke is a type of stroke that occurs due to the rupture of blood vessels in the brain therefore stopping their ability to transport blood as well as causing inappropriate bleeding into the surrounding brain tissue. Hemorrhagic stroke can be either intracerebral, where a blood vessel within the brain tissue ruptures, or subarachnoid, where a vessel in the subarachnoid space (surrounding the brain cortex) ruptures and pools blood around the outside of the brain and possibly the brainstem which can lead to dangerous increase in intracranial pressure.

Describe the general mechanism of action of tissue plasminogen activator (tPA). Indicate which type of stroke tPA is most often used to treat

Tissue plasminogen activator works by converting plasminogen into its active form plasmin, which is an enzyme that breaks down fibrin, and can result in the breakdown of blood clots. This happens rather quickly and can save a person with a thrombotic or embolic stroke from permanent damage if given quickly enough

Identify two brain proteins that appear in blood after brain injury and describe the clinical utility of quantifying these two brain proteins in blood after head trauma

Two proteins that are measurable in the blood following a traumatic head injury are ubiquitin C-terminal hydrolase and glial fibrillary acidic protein. The presence of these proteins in the blood can reliably predict the presence of visible brain trauma on a CT scan approximately 97.5% of the time

Uncal Herniation

Uncal herniation occurs when the uncus (innermost part of temporal lobe) has enough pressure placed on it then moves towards the tentorium and puts pressure on the brainstem. This is clearly the more dangerous of the two herniations discussed as it can possibly affect the vital centers of life