McCance Chapter 18 Disorders of the Central and Peripheral Nervous Systems Practice Questions

Diffuse axonal injuries of the brain often result in:

A. reduced levels of consciousness

B. mild but permanent dysfunction

C. fine motor tremors

D. visual disturbances

Correct answer: A. reduced levels of consciousness

Why it's correct: Diffuse axonal injury (DAI) is a type of traumatic brain injury that results from shearing forces that occur during rapid acceleration or deceleration of the brain, such as in motor vehicle accidents or falls. These forces lead to widespread damage to the brain's white matter tracts, which are responsible for connecting different brain regions. This type of injury disrupts normal brain function, particularly the network pathways that support consciousness and arousal. As a result, individuals with DAI often experience a reduction in their level of consciousness, ranging from drowsiness to coma.

Why others are wrong:

B. mild but permanent dysfunction: DAI typically results in severe impairment rather than mild dysfunction. The widespread nature of the injury usually leads to significant and long-term deficits, including cognitive, motor, and sensory impairments, which can be profound and permanent.

C. fine motor tremors: While DAI can lead to motor deficits due to the interruption of motor tract pathways, fine motor tremors are not a hallmark of this condition. Tremors are more commonly associated with diseases that affect the cerebellum or basal ganglia, rather than diffuse white matter injury.

D. visual disturbances: Visual disturbances can occur in various types of brain injuries, but they are not a defining characteristic of DAI. Such symptoms would be more specifically associated with localized damage to the visual processing areas of the brain or the visual pathways, rather than the diffuse injury seen in DAI.

What event is most likely to occur to the brain in a classic cerebral concussion?

A. brief period of vital sign instability

B. cerebral edema throughout the cerebral cortex

C. cerebral edema throughout the diencephalon

D. disruption of axons extending from the diencephalon and brainstem

Correct answer: A. brief period of vital sign instability

Why it's correct: In a classic cerebral concussion, one of the initial and temporary clinical manifestations that can be observed is a brief period of vital sign instability. This can include alterations in pulse rate, respiratory rate, and blood pressure. These changes are a result of the brain's response to the injury and the transient disruption in the brain's regulation of these autonomic functions.

Why others are wrong:

B. cerebral edema throughout the cerebral cortex: Cerebral edema is not typically an immediate consequence of a classic concussion. Concussions generally do not cause widespread swelling; instead, they are characterized by functional impairment rather than structural damage.

C. cerebral edema throughout the diencephalon: Similar to cerebral edema in the cerebral cortex, this is not characteristic of a classic concussion. Concussions affect brain function primarily due to neuronal dysfunction, not because of significant edema in the diencephalon.

D. disruption of axons extending from the diencephalon and brainstem: Axonal injury, such as diffuse axonal injury, is associated with more severe brain injury rather than a classic concussion. Concussions are typically marked by a reversible neurological dysfunction without extensive axonal damage.

Which disorder has clinical manifestations that include decreased consciousness for up to 6 hours, as well as retrograde and posttraumatic amnesia?

A. mild concussion

B. classic concussion

C. cortical contusion

D. acute subdural hematoma

Correct answer: B. classic concussion

Why it's correct: A classic concussion is characterized by a transient loss of consciousness immediately following the injury, with amnesia for the events surrounding the incident (retrograde amnesia) and after the incident (posttraumatic amnesia). The loss of consciousness in a classic concussion typically lasts from a few seconds to a few minutes, but the individual may experience confusion and decreased consciousness for up to 6 hours following the injury. Retrograde amnesia involves the loss of memory for events that occurred before the injury, while posttraumatic amnesia refers to the loss of memory for events during and after the injury.

Why others are wrong:

A. mild concussion: A mild concussion may result in transient confusion or amnesia without a significant period of decreased consciousness, and typically, the amnesia does not last up to 6 hours.

C. cortical contusion: Cortical contusions, which are bruises of the brain tissue, can result in symptoms that last much longer than 6 hours and often involve more focal neurological deficits depending on the contusion's location.

D. acute subdural hematoma: An acute subdural hematoma is a collection of blood between the brain surface and the dura mater, usually due to tearing of bridging veins as a result of head injury. This condition often leads to a longer period of decreased consciousness and is more severe than a classic concussion, frequently requiring surgical intervention.

What group is most at risk of spinal cord injury from minor trauma?

A. children

B. adolescents

C. adults

D. older adults

Correct answer: D. older adults

Why it's correct: Older adults are at a greater risk of spinal cord injury from minor trauma due primarily to the degenerative changes that occur in the spine with aging, such as cervical spondylosis. These changes can make the spinal cord more susceptible to injury from relatively minor traumatic events. Furthermore, older adults often have a combination of factors such as decreased bone density (osteoporosis), poorer balance, and slower reflexes that increase the risk of falls and subsequent injury.

Why others are wrong:

A. children: While children can suffer from spinal cord injuries, their risk from minor trauma is not as high as in older adults. Children's flexibility and the relative robustness of their spinal columns typically afford them some protection from minor traumas.

B. adolescents: Adolescents are not the most at-risk group for spinal cord injury from minor trauma. While they are more likely to engage in risky behaviors that can lead to severe injuries, minor trauma is less likely to cause significant spinal injury in this age group compared to older adults.

C. adults: Adults, in general, are at risk of spinal cord injury, but the group that is most vulnerable to injury from minor trauma is the older adult population, not the adult population at large.

The edema of the upper cervical cord after spinal injury is considered life threatening because of which possible outcome?

A. hypovolemic shock from blood lost during the injury

B. breathing difficulties from an impairment to the diaphragm

C. head injury that likely occurred during the injury

D. spinal shock immediately after the injury

Correct answer: B. breathing difficulties from an impairment to the diaphragm

Why it's correct: The edema of the upper cervical cord is considered life-threatening because it may impair the function of the phrenic nerve, which innervates the diaphragm, the primary muscle of respiration. If the upper cervical cord is swollen, it can lead to respiratory failure due to diaphragmatic paralysis or severe weakness. This is a medical emergency and requires immediate attention, often including mechanical ventilation to support breathing.

Why others are wrong:

A. hypovolemic shock from blood lost during the injury: While blood loss can occur with traumatic injuries, the edema of the spinal cord itself does not result in hypovolemic shock. Hypovolemic shock is related to fluid loss from the vascular system, not edema within the spinal cord.

C. head injury that likely occurred during the injury: Although a head injury may accompany a spinal injury, the edema of the upper cervical cord is specifically life-threatening due to its potential to impair respiratory function, not because of any associated head injury.

D. spinal shock immediately after the injury: Spinal shock refers to the temporary loss of spinal reflex activity that occurs below the level of a spinal cord injury. While this is a serious condition, it is not the primary reason why edema of the upper cervical cord is life-threatening. The critical issue with cervical edema is the risk of respiratory failure.

What indicates that spinal shock is terminating?

A. voluntary movement below the level of injury

B. reflex emptying of the bladder

C. paresthesia below the level of injury

D. decreased deep tendon reflexes and flaccid paralyis

Correct answer: B. reflex emptying of the bladder

Why it's correct: Spinal shock is a condition typically occurring immediately after a spinal cord injury, characterized by a temporary loss of all reflexes and motor and sensory activity below the level of injury. Termination of spinal shock is indicated by the return of reflexes. The reflex emptying of the bladder is a specific reflex that can indicate the end of spinal shock. It signifies that the nervous system is regaining the ability to control bladder functions reflexively, which implies some level of return of spinal cord reflex activity.

Why others are wrong:

A. voluntary movement below the level of injury: Voluntary movement returning would indicate recovery of motor pathways and is separate from the reflex activity associated with the resolution of spinal shock.

C. paresthesia below the level of injury: While paresthesias may occur during recovery from a spinal cord injury, they are not a definitive indication that spinal shock is terminating.

D. decreased deep tendon reflexes and flaccid paralysis: This option describes the characteristics of spinal shock itself, not its resolution. Spinal shock is associated with decreased reflexes and flaccid paralysis immediately after injury.

What term is used to describe the complication that can result from a spinal cord injury above T6 that is producing paroxysmal hypertension, as well as piloerection and sweating above the spinal cord lesion?

A. craniosacral dysreflexia

B. parasympathetic dysreflexia

C. autonomic hyperreflexia

D. retrograde hyperreflexia

Correct answer: C. autonomic hyperreflexia

Why it's correct: Autonomic hyperreflexia, also known as autonomic dysreflexia, is a potentially life-threatening condition that can occur in individuals with spinal cord injuries above the T6 level. It is characterized by a sudden and severe hypertensive response to stimuli that would normally not cause such a reaction, such as a full bladder or bowel. The injury interrupts the normal pathways by which the body would manage such stimuli, leading to an uncontrolled sympathetic response. This condition is marked by high blood pressure, pounding headache, piloerection (goosebumps), and sweating above the level of injury.

Why others are wrong:

A. craniosacral dysreflexia: This term is not recognized as a valid medical condition related to spinal cord injuries and does not accurately describe the phenomenon in question.

B. parasympathetic dysreflexia: The term is incorrect as the condition is related to an overactivity of the sympathetic nervous system, not the parasympathetic nervous system.

D. retrograde hyperreflexia: The term “retrograde hyperreflexia” does not pertain to any recognized medical condition associated with spinal cord injuries and is not accurate in this context.

Why does a person who has a spinal cord injury experience faulty control of sweating?

A. the hypothalamus is unable to regulate body heat as a result of damage to the sympathetic nervous system

B. the thalamus is unable to regulate body heat as a result of damage to the sympathetic nervous system

C. the hypothalamus is unable to regulate body heat as a result of damage to the parasympathetic nervous system

D. the thalamus is unable to regulate body heat as a result of damage to spinal nerve root

Correct answer: A. the hypothalamus is unable to regulate body heat as a result of damage to the sympathetic nervous system

Why it's correct: The hypothalamus is the part of the brain that regulates body temperature. After a spinal cord injury, especially one that affects the thoracic spine where sympathetic outflow to the body originates, the connection between the hypothalamus and the sympathetic nervous system can be disrupted. As a result, the person can have difficulty with thermoregulation, including the control of sweating, because the sympathetic nervous system innervates sweat glands and controls sweating as part of body heat regulation.

Why others are wrong:

B. the thalamus is unable to regulate body heat as a result of damage to the sympathetic nervous system: The thalamus is primarily involved in sensory signal relay and not in the regulation of body heat or sweating, which are functions of the hypothalamus and sympathetic nervous system.

C. the hypothalamus is unable to regulate body heat as a result of damage to the parasympathetic nervous system: The hypothalamus regulates body heat through the sympathetic nervous system, not the parasympathetic nervous system. The parasympathetic nervous system is more often associated with rest and digest functions.

D. the thalamus is unable to regulate body heat as a result of damage to spinal nerve root: Again, the thalamus is not the part of the brain responsible for body heat regulation; the hypothalamus is. Damage to a spinal nerve root would not affect the thalamus.

Autonomic hyperreflexia-induced bradycardia is a result of stimulation of the:

A. sympathetic nervous system to beta-adrenergic receptors to the sinoatrial node

B. carotid sinus to the vagus nerve to the sinoatrial node

C. parasympathetic nervous system to the glossopharyngeal nerve to the AV node

D. bundle branches to the alpha-adrenergic receptors to the sinoatrial node

Correct answer: B. carotid sinus to the vagus nerve to the sinoatrial node

Why it's correct: Autonomic hyperreflexia-induced bradycardia occurs as a result of an uncontrolled sympathetic response that leads to hypertension. The body then tries to compensate for this hypertension by stimulating the carotid sinus, which in turn activates the vagus nerve, a parasympathetic nerve that innervates the heart. This increased parasympathetic input to the sinoatrial (SA) node of the heart causes a decrease in heart rate, known as bradycardia. This is a reflexive response to high blood pressure.

Why others are wrong:

A. sympathetic nervous system to beta-adrenergic receptors to the sinoatrial node: Stimulation of the sympathetic nervous system and beta-adrenergic receptors would typically result in an increase in heart rate, not a decrease.

C. parasympathetic nervous system to the glossopharyngeal nerve to the AV node: The glossopharyngeal nerve does not primarily innervate the AV node for heart rate control; it is involved with sensory innervation of the pharynx and back of the throat, among other functions.

D. bundle branches to the alpha-adrenergic receptors to the sinoatrial node: The bundle branches are part of the heart's electrical conduction system that carries impulses but are not directly involved in autonomic control. Alpha-adrenergic receptors are not primarily involved in the heart rate response described here.

A herniation of which disk will likely result in motor and sensory changes of the lateral lower legs and soles of the feet?

A. L2-L3

B. L3-L5

C. L5-S1

D. S2-S3

Correct answer: C. L5-S1

Why it's correct: A herniation of the L5-S1 intervertebral disk would affect the nerves that supply the lateral lower legs and soles of the feet, leading to motor and sensory changes in these areas. The L5 nerve root affects muscles and skin in the dorsum and lateral aspect of the foot, and the S1 nerve root affects the plantar aspect of the foot, which includes the soles.

Why others are wrong:

A. L2-L3: A herniation at L2-L3 would likely affect nerve function at a higher level on the leg, not specifically targeting the lateral lower legs and soles of the feet.

B. L3-L5: While a herniation here might affect the lower legs, it is not as specific for the lateral aspect and sole of the foot as the L5-S1 level.

D. S2-S3: A herniation at this level would be more likely to affect the function of the genitals and perineum, as well as potentially causing some motor function changes in the legs, but it is not as closely associated with the lateral lower legs and soles of the feet as the L5-S1 level.

Which condition poses the highest risk for a cerebrovascular accident (CVA)?

A. insulin-resistant diabetes mellitus

B. hypertension

C. polycythemia

D. smoking

Correct answer: B. hypertension

Why it's correct: Hypertension, or high blood pressure, is the leading risk factor for cerebrovascular accidents (CVAs), also known as strokes. The chronic elevation of blood pressure can lead to damage to the blood vessel walls, which increases the risk of clot formation (thrombosis), the development of atherosclerosis (hardening and narrowing of the arteries), and the potential for a blood vessel to rupture (hemorrhagic stroke). These pathologies directly contribute to the risk of a CVA.

Why others are wrong:

A. insulin-resistant diabetes mellitus: While insulin-resistant diabetes mellitus is a significant risk factor for CVA due to its contribution to atherosclerosis and other cardiovascular diseases, it is not the primary risk factor when compared to hypertension.

C. polycythemia: Polycythemia, a condition with an increased concentration of hemoglobin in the blood due to increased red cell numbers, increases blood viscosity and thus the risk of thrombosis. However, hypertension has a more direct and significant impact on CVA risk.

D. smoking: Smoking is a well-established risk factor for CVA because it damages the blood vessels and increases the risk of atherosclerosis. Nonetheless, hypertension is still recognized as a more significant and prevalent risk factor for stroke.

A right hemisphere embolic CVA has resulted in left-sided paralysis and reduced sensation of the left foot and leg. Which cerebral artery is most likely affected by the emboli?

A. middle cerebral

B. vertebral

C. posterior cerebral

D. anterior cerebral

Correct answer: D. anterior cerebral

Why it's correct: The anterior cerebral artery supplies the medial portions of the frontal lobe and superior medial parietal lobes. An embolism in the anterior cerebral artery would lead to decreased blood flow to these areas, potentially causing paralysis and reduced sensation in the contralateral (opposite side of the body) lower extremities, which the question describes as the left foot and leg.

Why others are wrong:

A. middle cerebral: The middle cerebral artery primarily supplies the lateral part of the cerebral cortex, including the areas responsible for face and arm motor and sensory functions, not the lower limbs.

B. vertebral: The vertebral artery, along with the basilar artery, supplies the brainstem and posterior part of the brain. An embolism here would typically not result in isolated left-sided lower limb deficits.

C. posterior cerebral: The posterior cerebral artery supplies the occipital lobe, the bottom part of the temporal lobe, and various other structures. An embolic stroke in this artery would more likely affect vision and other functions, not typically causing left-sided paralysis and reduced sensation of the leg.

Atrial fibrillation, rheumatic heart disease, and valvular prosthetics are risk factors for which type of stroke?

A. hemorrhagic

B. thrombotic

C. embolic

D. lacunar

Correct answer: C. embolic

Why it's correct: An embolic stroke occurs when an embolus, often a blood clot or other debris, travels through the bloodstream to the cerebral arteries and occludes one, interrupting blood flow and causing a stroke. Atrial fibrillation, rheumatic heart disease, and valvular prosthetics are conditions that predispose individuals to the formation of emboli. In atrial fibrillation, the heart's atria do not contract effectively, leading to blood stasis and clot formation, which can then travel to the brain. Similarly, rheumatic heart disease and valvular prosthetics can lead to altered blood flow and surface for clot formation, which can embolize.

Why others are wrong:

A. hemorrhagic: While those with rheumatic heart disease may be on anticoagulation which could increase the risk of bleeding, the conditions listed are not direct risk factors for a hemorrhagic stroke, which results from blood vessel rupture within the brain.

B. thrombotic: Thrombotic strokes are caused by clots forming directly at the clogged part of the blood vessel in the brain, which is not directly associated with atrial fibrillation, rheumatic heart disease, or valvular prosthetics.

D. lacunar: Lacunar strokes are small vessel diseases often associated with chronic hypertension and diabetes. They are not typically caused by embolism from cardiac sources.

Microinfarcts resulting in pure motor or pure sensory deficits are the result of which type of stroke?

A. embolic

B. hemorrhagic

C. lacunar

D. thrombotic

Correct answer: C. lacunar

Why it's correct: Lacunar strokes occur when there is occlusion of one of the small penetrating arteries that branch off from the larger cerebral arteries. They are often linked to hypertension and diabetes, which cause atherosclerotic changes and lipohyalinosis, leading to the development of these small infarcts. Lacunar strokes commonly present with specific clinical syndromes, such as pure motor hemiparesis or pure sensory stroke, which involve a complete but isolated type of deficit (either motor or sensory).

Why others are wrong:

A. embolic: An embolic stroke is usually caused by a clot that forms elsewhere in the body and travels to the brain, typically causing a more extensive area of brain damage than seen in lacunar strokes.

B. hemorrhagic: Hemorrhagic strokes occur due to bleeding into or around the brain and do not typically present with isolated deficits such as pure motor or pure sensory impairments.

D. thrombotic: Thrombotic strokes occur due to a clot forming in the arteries supplying the brain, typically leading to a broader range of symptoms depending on the cerebral artery's territory affected, not typically resulting in isolated deficits like pure motor or pure sensory strokes.

Which vascular malformation is characterized by arteries that feed directly into veins through vascular tangles of abnormal vessels?

A. cavernous angioma

B. capillary telangiectasia

C. arteriovenous angioma

D. arteriovenous malformation

Correct answer: D. arteriovenous malformation (AVM)

Why it's correct: An arteriovenous malformation (AVM) is a vascular anomaly where arteries connect directly to veins via a complex, tangled web of abnormal vessels, bypassing the capillary system. This can lead to a variety of problems, including an increased risk of bleeding (hemorrhage), seizures, and other neurological symptoms.

Why others are wrong:

A. cavernous angioma: A cavernous angioma is a vascular malformation that consists of a collection of dilated blood vessels with little or no intervening brain tissue, which may lead to seizures or hemorrhage but does not involve direct arteriovenous connections.

B. capillary telangiectasia: Capillary telangiectasia is a small malformation of capillaries that does not typically cause significant symptoms and does not feature direct arteriovenous connections.

C. arteriovenous angioma: While "arteriovenous angioma" may sound similar to AVM, it is not a term commonly used in medical literature or practice. The correct term for the condition described is arteriovenous malformation (AVM).

Which clinical finding is considered a diagnostic indicator for an arteriovenous malformation (AVM)

A. systolic bruit over the carotid artery

B. decreased level of consciousness

C. hypertension with bradycardia

D. diastolic bruit over the temporal artery

Correct answer: A. systolic bruit over the carotid artery

Why it's correct: A systolic bruit over the carotid artery can be a diagnostic indicator of an arteriovenous malformation (AVM) in the brain. An AVM is an abnormal connection between arteries and veins, bypassing the capillary system. Blood flow through an AVM is typically fast and can create a noise known as a bruit, which is often audible through auscultation with a stethoscope. This turbulent flow is most noticeable during systole when blood flow is strongest and the pressure gradient between the arteries and veins is highest.

Why others are wrong:

B. decreased level of consciousness: Decreased level of consciousness can be a sign of many different neurological conditions, including stroke, hemorrhage, or brain tumors, but it is not specific to AVM.

C. hypertension with bradycardia: Hypertension with bradycardia, often part of Cushing’s triad, is associated with increased intracranial pressure rather than being specific to AVMs.

D. diastolic bruit over the temporal artery: A diastolic bruit over the temporal artery may indicate a different vascular abnormality such as a high-flow carotid-cavernous fistula, but it is not a typical finding in AVM.

Which cerebral vascular hemorrhage causes meningeal irritation, photophobia, and positive Kernig and Brudzinski signs?

A. intracranial

B. subarachnoid

C. epidural

D. subdural

Correct answer: B. subarachnoid

Why it's correct: Subarachnoid hemorrhage typically causes meningeal irritation, which leads to photophobia and positive Kernig and Brudzinski signs. These symptoms occur because the blood irritates the meninges, which are the protective membranes covering the brain and spinal cord. Kernig and Brudzinski signs are clinical indicators of meningeal irritation.

Why others are wrong:

A. intracranial: Intracranial hemorrhage is a broad term that can encompass any bleeding within the cranial vault, including subarachnoid hemorrhage, but on its own, it does not specifically refer to bleeding into the subarachnoid space.

C. epidural: Epidural hemorrhage typically occurs between the dura mater and the skull following head trauma, and it classically presents with a lucid interval followed by a rapid decline in consciousness due to the accumulation of blood in the epidural space, not specifically meningeal irritation.

D. subdural: Subdural hemorrhage, bleeding that occurs beneath the dura mater but above the brain, may cause a decrease in consciousness and other neurological symptoms, but it is less commonly associated with the signs of meningeal irritation such as those seen in subarachnoid hemorrhage.

In adults, most intracranial tumors are located:

A. infratentorially

B. supratentiorially

C. laterally

D. posterolaterally

Correct answer: A. infratentorially

Why it's correct: In adults, most intracranial tumors are located supratentorially, which is above the tentorium cerebelli, including the cerebral hemispheres.

Why others are wrong:

A. infratentorially: This is actually the correct answer for children, not adults. Adult brain tumors are more commonly found supratentorially.

C. laterally: This does not provide a specific common location for intracranial tumors in adults.

D. posterolaterally: While tumors can occur in this area, it is not the most common location for adult brain tumors.

The most common primary central nervous system tumor is the:

A. microglioma

B. neuroblastoma

C. astrocytoma

D. neuroma

Correct answer: C. astrocytoma

Why it's correct: Astrocytomas are the most common primary central nervous system tumors, which originate from star-shaped brain cells called astrocytes. These tumors can occur in various parts of the brain and spinal cord and range in behavior from benign (noncancerous) to highly malignant (cancerous).

Why others are wrong:

A. microglioma: Microglioma is not a standard classification for a primary brain tumor. Microglia are cells within the brain that act as part of the immune system, but tumors arising from these cells are not classified as microgliomas.

B. neuroblastoma: Neuroblastoma is a cancer that arises from immature nerve cells in children, most commonly outside the central nervous system, especially in the adrenal glands.

D. neuroma: Neuroma refers to a benign growth of nerve tissue, and while schwannomas (often referred to as acoustic neuromas when in the vicinity of the auditory nerve) are common, they are not the most common primary brain tumor.

Meningiomas characteristically compress from:

A. within neural tissues

B. outside spinal nerve roots

C. outside the spinal cord

D. within the subarachnoid space

Correct answer: C. outside the spinal cord

Why it's correct: Meningiomas are tumors that arise from the meninges, the membranous layers surrounding the brain and spinal cord. They typically grow outside the brain or spinal cord tissue itself, exerting pressure on these structures from the outside as they enlarge. When meningiomas occur in the spinal region, they characteristically compress the spinal cord externally.

Why others are wrong:

A. within neural tissues: Meningiomas do not typically arise from within the neural tissues but from the meninges surrounding the neural tissues.

B. outside spinal nerve roots: While meningiomas can affect the spinal nerve roots by external compression, this is not the characteristic presentation; they are more known for compressing the spinal cord itself when in the spinal canal.

D. within the subarachnoid space: Meningiomas originate from the meninges and can protrude into the subarachnoid space, but they do not typically arise from within this space and are known to compress the brain or spinal cord from outside.

What is the central component of the pathogenic model of multiple sclerosis?

A. Myelination of nerve fibers in the PNS

B. demyelination of nerve fibers in the CNS

C. development of neurofibrillary tangles in the CNS

D. inherited autosomal dominant trait with high penetrance

Correct answer: B. demyelination of nerve fibers in the CNS

Why it's correct: Multiple sclerosis (MS) is characterized by the demyelination of nerve fibers in the central nervous system (CNS). This demyelination disrupts the ability of the nerves to conduct electrical impulses efficiently, leading to the neurological symptoms associated with the disease.

Why others are wrong:

A. Myelination of nerve fibers in the PNS: MS does not involve myelination; it involves demyelination, and it affects the CNS, not the peripheral nervous system (PNS).

C. development of neurofibrillary tangles in the CNS: Neurofibrillary tangles are associated with Alzheimer's disease, not MS.

D. inherited autosomal dominant trait with high penetrance: MS is not typically inherited as an autosomal dominant trait with high penetrance. The exact cause is unknown, but it is believed to involve a combination of genetic susceptibility and environmental factors.

A blunt force injury to the forehead would result in a coup injury to which region of the brain?

A. frontal

B. temporal

C. parietal

D. occipital

Correct answer: A. frontal

Why it's correct: A blunt force injury to the forehead would result in a coup injury to the frontal region of the brain. A coup injury occurs directly under the site of impact where the force is applied.

Why others are wrong:

B. temporal: A temporal coup injury would require an impact to the side of the head, not the forehead.

C. parietal: A parietal coup injury would occur if the impact was on the upper side of the head, not the forehead.

D. occipital: An occipital coup injury would be caused by a blow to the back of the head, not the forehead.

A blunt force injury to the forehead would result in a contrecoup injury to which region of the brain?

A. frontal

B. temporal

C. parietal

D. occipital

Correct answer: D. occipital

Why it's correct: When there is a blunt force impact to the forehead, the force can cause the brain to move within the skull. This movement may result in injury to the brain tissue on the opposite side of the initial impact due to the brain rebounding against the skull. This is known as a contrecoup injury, which often affects the occipital lobe when the force is directed at the forehead.

Why others are wrong:

A. frontal: The frontal lobe is the area of the brain that is located at the front and is directly impacted by a blunt force injury to the forehead. The term "contrecoup" refers specifically to injury on the side opposite to the impact, so an injury to the frontal lobe would not be a contrecoup injury in this case.

B. temporal: While the temporal lobes are located on the sides of the brain and could theoretically be affected by the motion of the brain within the skull during an impact, they are not typically the site of a contrecoup injury resulting from a frontal blow. Instead, the temporal lobes might be more directly impacted by lateral forces to the head.

C. parietal: The parietal lobes, located near the top and center of the brain, would not generally be the site of a contrecoup injury from a frontal impact. Contrecoup injuries are most likely to occur at the point directly opposite the site of impact, which, in the case of a blow to the forehead, would be the occipital lobe at the back of the brain.

Spinal cord injuries most likely occur in which region?

A. cervical and thoracic

B. thoracic and lumbar

C. lumbar and sacral

D. cervical and thoracic-lumbar

Correct answer: D. cervical and thoracic-lumbar

Why it's correct: Spinal cord injuries are most likely to occur at the cervical level (neck), which is the most mobile part of the spine and at the thoracic-lumbar junction, which is where the spine transitions from the thoracic (mid-back) to the lumbar (lower back) region. These areas are more vulnerable to injury due to their anatomical and biomechanical properties.

Why others are wrong:

A. cervical and thoracic: While cervical injuries are common, thoracic spinal injuries are less common due to the stabilizing effect of the rib cage.

B. thoracic and lumbar: This combination is less common than cervical and thoracic-lumbar injuries, as the lumbar spine is generally less prone to injury compared to the cervical region and thoracic-lumbar junction.

C. lumbar and sacral: Lumbar and sacral regions are less frequently injured than the cervical region and thoracic-lumbar junction, likely due to greater flexibility and lower incidence of traumatic force application in these areas.

The most likely rationale for body temperature fluctuations after cervical spinal cord injury is that the person has:

A. developed bilateral pneumonia or a urinary tract infection

B. sustain sympathetic nervous system damage resulting in disturbed thermal control

C. sustained a head injury that damaged the hypothalamus's ability to regulate temperature

D. developed septicemia from posttrauma infection

Correct answer: B. sustain sympathetic nervous system damage resulting in disturbed thermal control

Why it's correct: Body temperature regulation is largely controlled by the hypothalamus and the sympathetic nervous system. After a cervical spinal cord injury, the connection between the sympathetic nervous system and the thermoregulatory centers in the hypothalamus may be disrupted. This can result in an impaired ability to regulate body temperature, leading to fluctuations. The sympathetic nervous system is responsible for the physiological responses to temperature changes, and when it's damaged, these responses can become erratic or nonexistent.

Why others are wrong:

A. developed bilateral pneumonia or a urinary tract infection: While infections can cause fever and fluctuations in body temperature, this option does not account for the direct effect of a cervical spinal cord injury on the body's temperature control mechanisms.

C. sustained a head injury that damaged the hypothalamus's ability to regulate temperature: This answer would be plausible if there was evidence of a head injury affecting the hypothalamus. However, the question specifically states that the injury is to the cervical spinal cord, not the brain.

D. developed septicemia from posttrauma infection: Septicemia can cause temperature fluctuations, but again, this option does not directly address the changes in body temperature regulation that can occur as a result of damage to the sympathetic nervous system from a spinal cord injury.

A man who sustained a cervical spinal cord injury 2 days ago sudenly develops severe hypertension and bradycardia. He reports severe head pain and blurred vision. The most likely explanation for these clinical manifestations is that he is:

A. experiencing acute anxiety

B. developing spinal shock

C. developing autonomic hyperreflexia

D. experiencing parasympathetic areflexia

Correct answer: C. developing autonomic hyperreflexia

Why it's correct: Autonomic hyperreflexia (also known as autonomic dysreflexia) is a condition that can occur in individuals with spinal cord injuries above the level of T6. It is a potentially life-threatening medical emergency characterized by severe hypertension and a slow heart rate (bradycardia), often in response to a noxious stimulus below the level of injury. Symptoms such as severe headache and blurred vision, as described, are consistent with this diagnosis.

Why others are wrong:

A. experiencing acute anxiety: While anxiety can cause hypertension, it does not typically cause severe hypertension along with bradycardia and the other symptoms described.

B. developing spinal shock: Spinal shock is characterized by a temporary loss of all reflexes and motor and sensory activity below the level of injury, not by severe hypertension and bradycardia.

D. experiencing parasympathetic areflexia: Parasympathetic areflexia would not typically result in severe hypertension and bradycardia; rather, it might lead to unopposed parasympathetic activity, which generally causes low blood pressure and bradycardia.

The type of vascular malformation that most often results in hemorrhage:

A. cavernous angioma

B. venous angioma

C. capillary telangiectasia

D. arteriovenous malformation

Correct answer: D. arteriovenous malformation

Why it's correct: Arteriovenous malformations (AVMs) are abnormal connections between arteries and veins, bypassing the capillary system. They are prone to bleeding because the high-pressure blood flow from arteries goes directly into veins, which are not designed to handle such pressure. AVMs are a common cause of hemorrhagic strokes.

Why others are wrong:

A. cavernous angioma: Cavernous angiomas can bleed, but they are less likely to cause significant hemorrhage compared to AVMs because the blood flow in angiomas is typically slow, and the vessels are less likely to rupture.

B. venous angioma: Venous angiomas are rare and usually do not result in hemorrhage because they consist of normal or slightly enlarged veins without the high-pressure arterial flow that is present in AVMs.

C. capillary telangiectasia: Capillary telangiectasias are generally small and have a low flow; they rarely bleed and, when they do, the hemorrhages are usually small.

Artheromatous plaques are most commonly found:

A. in larger veins

B. near capillary sphincters

C. at branches of arteries

D. on the venous sinuses

Correct answer: C. at branches of arteries

Why it's correct: Atheromatous plaques are most commonly found at branches of arteries because these areas are subject to turbulent blood flow, which can damage the endothelium and promote the development of plaques. The branch points in arteries are where the mechanical stress and shear forces on the vessel walls are greatest, creating an environment conducive to the development of atherosclerosis.

Why others are wrong:

A. in larger veins: Atherosclerosis typically affects arteries, not veins, due to the higher pressure and stress placed on arterial walls.

B. near capillary sphincters: Atheromatous plaques do not form near capillary sphincters. Capillaries are too small for plaque formation, and sphincters regulate blood flow into capillaries, not the large arteries where plaques form.

D. on the venous sinuses: Venous sinuses, especially in the brain, do not experience the type of pressure and flow-related stress that leads to plaque formation. Plaques are typically an arterial issue.

Multiple Sclerosis is best described as a(an):

A. central nervous system demyelination, possibly from an immunogenetic virus

B. inadequate supply of acetylcholine at the neurotransmitter junction as a result of an autoimmune disorder

C. depletion of dopamine in the CNS as a result of a virus

D. degenerative disorder of lower and upper motor neurons caused by viral-immune factors

Correct answer: A. central nervous system demyelination, possibly from an immunogenetic virus

Why it's correct: Multiple Sclerosis (MS) is characterized by demyelination in the central nervous system (CNS). It is thought to be an autoimmune disorder, where the immune system attacks the myelin sheath covering nerve fibers, leading to disrupted electrical impulses in the brain and spinal cord. The role of genetics and possible environmental triggers, such as a virus, is an area of ongoing research.

Why others are wrong:

B. inadequate supply of acetylcholine at the neurotransmitter junction as a result of an autoimmune disorder: This description is more indicative of Myasthenia Gravis, not MS.

C. depletion of dopamine in the CNS as a result of a virus: Dopamine depletion in the CNS is associated with Parkinson's disease rather than MS.

D. degenerative disorder of lower and upper motor neurons caused by viral-immune factors: The degeneration of lower and upper motor neurons is characteristic of Amyotrophic Lateral Sclerosis (ALS), not MS.

What is the most common opportunistic infection associated with AIDS?

A. non-hodgkin lymphoma

B. kaposi sarcoma

C. toxoplasmosis

D. cytomegalovirus

Correct answer: C. toxoplasmosis

Why it's correct: Toxoplasmosis, caused by the protozoan parasite Toxoplasma gondii, is the most common opportunistic infection associated with AIDS. It often presents as a central nervous system infection in individuals who have a significantly compromised immune system, particularly those with AIDS. The infection can cause severe manifestations such as encephalitis, which can be life-threatening.

Why others are wrong:

A. non-hodgkin lymphoma: While Non-Hodgkin lymphoma is associated with AIDS, it is a type of cancer rather than an opportunistic infection. It is more common in individuals with a compromised immune system, including those with AIDS, but it is not caused by an infectious agent.

B. kaposi sarcoma: Kaposi sarcoma is a malignancy associated with Human Herpesvirus 8 (HHV-8), particularly in individuals with AIDS. However, it is not classified as an opportunistic infection, but rather as an AIDS-defining malignancy.

D. cytomegalovirus: Cytomegalovirus (CMV) infection is common in individuals with AIDS, but it is typically not the most common opportunistic infection. CMV can cause a range of illnesses in those with AIDS, including retinitis, colitis, and encephalitis, but it ranks behind toxoplasmosis in frequency.

It is true that Guillain-Barre syndrome:

A. is preceded by a viral illness

B. involves a deficit in acetylcholine

C. results in asymmetric paralysis

D. is an outcome of HIV

Correct answer: A. is preceded by a viral illness

Why it's correct: Guillain-Barre syndrome (GBS) is commonly preceded by a viral or bacterial illness, such as a respiratory or gastrointestinal infection. The infection can trigger an immune response that mistakenly attacks the peripheral nerves, leading to demyelination and the characteristic symptoms of GBS.

Why others are wrong:

B. involves a deficit in acetylcholine: Guillain-Barre syndrome does not involve a deficit in acetylcholine. Instead, it is characterized by an immune-mediated attack on the peripheral nerves' myelin sheath.

C. results in asymmetric paralysis: GBS typically causes symmetrical weakness that starts in the lower extremities and ascends; it does not cause asymmetric paralysis.

D. is an outcome of HIV: While HIV can cause a variety of neurological problems, Guillain-Barre syndrome is not considered an outcome of HIV. It's associated with an aberrant immune response to a preceding infection.

It is true that myasthenia gravis:

A. is an acute autoimmune disease

B. affects the nerve roots

C. may result in adrenergic crisis

D. causes muscle weakness

Correct answer: D. causes muscle weakness

Why it's correct: Myasthenia gravis is an autoimmune disorder characterized by the production of antibodies against acetylcholine receptors at the neuromuscular junction. This blocks the transmission of nerve impulses to muscles, leading to muscle weakness and fatigue, especially with continued use.

Why others are wrong:

A. is an acute autoimmune disease: Myasthenia gravis is considered a chronic autoimmune disease, not an acute one. Its course may fluctuate, and symptoms can vary in severity over time.

B. affects the nerve roots: Myasthenia gravis does not primarily affect the nerve roots. It affects the neuromuscular junction, where nerves connect with muscles.

C. may result in adrenergic crisis: Myasthenia gravis can lead to a myasthenic crisis, which is an exacerbation of muscle weakness, leading to respiratory failure. However, it does not result in an adrenergic crisis, which is a term not typically associated with myasthenia gravis.

In which disorder are acetylcholine receptor antibodies produced against acetylcholine receptors?

A. Guillain-Barre syndrome

B. multiple sclerosis

C. myasthenia gravis

D. parkinson disease

Correct answer: C. myasthenia gravis

Why it's correct: Myasthenia gravis is specifically characterized by the production of antibodies against acetylcholine receptors at the neuromuscular junction. These antibodies interfere with the action of acetylcholine, a neurotransmitter essential for the communication between nerve and muscle, leading to muscle weakness.

Why others are wrong:

A. Guillain-Barre syndrome: Guillain-Barre syndrome is associated with the immune system attacking the peripheral nerves' myelin sheath, not acetylcholine receptors.

B. multiple sclerosis: Multiple sclerosis involves an immune-mediated process that affects the central nervous system, particularly the brain and spinal cord, and does not involve the production of antibodies against acetylcholine receptors.

D. parkinson disease: Parkinson's disease involves the degeneration of dopaminergic neurons in the substantia nigra of the brain and does not involve an immune response against acetylcholine receptors.

Multiple sclerosis and Guillain-barre syndrome are similar in that they both:

A. result from demyelination by an immune reaction

B. cause permanent destruction of peripheral nerves

C. result from inadequate production or neurotransmitters

D. block acetylcholine receptor sites at the myoneuronal junction

Correct answer: A. result from demyelination by an immune reaction

Why it's correct: Both multiple sclerosis and Guillain-Barre syndrome involve the immune-mediated demyelination of nerves. In multiple sclerosis, this demyelination occurs in the central nervous system, while in Guillain-Barre syndrome, it occurs in the peripheral nervous system.

Why others are wrong:

B. cause permanent destruction of peripheral nerves: Multiple sclerosis does not typically cause permanent destruction of peripheral nerves, as it affects the central nervous system. Guillain-Barre syndrome can cause severe damage to peripheral nerves, but many patients recover function with treatment.

C. result from inadequate production or neurotransmitters: Neither multiple sclerosis nor Guillain-Barre syndrome is primarily a disorder of neurotransmitter production. They are demyelinating diseases where the immune system attacks nerve coverings, not neurotransmitter pathways.

D. block acetylcholine receptor sites at the myoneuronal junction: Blocking acetylcholine receptor sites at the neuromuscular junction is characteristic of myasthenia gravis, not multiple sclerosis or Guillain-Barre syndrome.

Which clinical manifestation is characteristic of cluster headaches? (Select all that apply)

A. preheadache aura

B. severe unilateral tearing

C. gradual onset of a tight band around the head

D. significant unilateral, temporal pain

E. pain lasting from 30 to 120 minutes

Correct answers:
B. severe unilateral tearing
D. significant unilateral, temporal pain
E. pain lasting from 30 to 120 minutes

Why it's correct:

Cluster headaches are known for a very specific set of symptoms which are quite distinctive from other types of headaches like migraines or tension-type headaches.

• B. Severe unilateral tearing is correct because cluster headaches typically present with severe pain on one side of the head, often around the eye, which can lead to tearing or redness of the eye on the affected side.

• D. Significant unilateral, temporal pain is correct because the pain of cluster headaches is typically focused on one side of the head, often around the temple, and is described as very severe.

• E. Pain lasting from 30 to 120 minutes is correct because the duration of cluster headaches fits this timeframe. The headaches can occur several times a day in a "cluster" period, which may last for weeks or months.

Why others are wrong:

A. Preheadache aura: This symptom is more characteristic of migraines rather than cluster headaches. Migraines often have a prodrome or aura phase, which can involve visual disturbances or other sensory changes before the headache pain begins.

C. Gradual onset of a tight band around the head: This is descriptive of a tension-type headache, which typically presents as a feeling of a tight band or pressure around the forehead or back of the head and neck. Cluster headaches usually have a rapid onset and do not create a sensation of pressure or a tight band.

What are the initial clinical manifestations immediately noted after a spinal cord injury? (Select all that apply)

A. headache

B. bladder incontinence

C. loss of deep tendon reflexes

D. hypertension

E. flaccid paralysis

Correct answer:
B. bladder incontinence
C. loss of deep tendon reflexes
E. flaccid paralysis

Why it's correct: The initial clinical manifestations immediately after a spinal cord injury include spinal shock, which is characterized by bladder incontinence, loss of deep tendon reflexes, and flaccid paralysis below the level of injury. These symptoms are due to the sudden loss of spinal cord function and the subsequent loss of autonomic, sensory, and reflex activity below the injury level.

Why others are wrong:

A. headache: While headache may be present due to associated trauma, it is not considered a direct and immediate clinical manifestation of spinal cord injury itself.

D. hypertension: Hypotension, not hypertension, is more commonly associated with the acute phase of spinal cord injury, especially in higher injuries, due to loss of sympathetic tone and resulting vasodilation.

Match the terms with the corresponding descriptions.

______ A. Complication of mastoiditis

______ B. Opportunistic infection

______ C. CNS manifestation of tuberculosis

______ D. Mosquito-borne viral infection

______ E. Tick-borne bacterial infection

Meningitis

ANS: C

Match the terms with the corresponding descriptions.

______ A. Complication of mastoiditis

______ B. Opportunistic infection

______ C. CNS manifestation of tuberculosis

______ D. Mosquito-borne viral infection

______ E. Tick-borne bacterial infection

Encephalitis

ANS: D

Match the terms with the corresponding descriptions.

______ A. Complication of mastoiditis

______ B. Opportunistic infection

______ C. CNS manifestation of tuberculosis

______ D. Mosquito-borne viral infection

______ E. Tick-borne bacterial infection

Cryptococcus neoformans

ANS: B

Match the terms with the corresponding descriptions.

______ A. Complication of mastoiditis

______ B. Opportunistic infection

______ C. CNS manifestation of tuberculosis

______ D. Mosquito-borne viral infection

______ E. Tick-borne bacterial infection

Brain abscess

ANS: A

Match the terms with the corresponding descriptions.

______ A. Complication of mastoiditis

______ B. Opportunistic infection

______ C. CNS manifestation of tuberculosis

______ D. Mosquito-borne viral infection

______ E. Tick-borne bacterial infection

Lyme disease

ANS: E