The Neurological Examination and Diagnostic Test Flashcards
1
Q
- An 85-year-old man is being evaluated for gait difficulties. On examination it is found that joint proprioception is absent in his toes. People with impaired position sense will usually fall if they stand with their feet together and do which of the following?
a. Flex the neck
b. Extend their arms in front of them
c. Flex the knees
d. Turn the head
e. Close their eyes
A
- The answer is E. (Victor, pp 123, 165–166.) Standing with the feet together and the eyes closed is the Romberg test. The person with poor position sense needs visual cues to remain standing. This test was introduced as a helpful way to check for deficits associated with tabes dorsalis, a form of neurosyphilis. In tabes dorsalis, the dorsal columns of the spinal cord are damaged. These dorsal or posterior columns carry the nerve fibers that transmit vibration and position sense to the brain. With the widespread use of penicillin, tabes dorsalis has become rare in industrialized nations, and impaired position sense is much more likely to be a consequence of diabetes mellitus or alcoholism. In both of these conditions, the impaired position sense is much more likely to be a consequence of damage to nerves in the limbs than of damage to the posterior columns of the spinal cord. In performing the test, it is important to remember that even normal people will tend to sway slightly more when their eyes are closed, and that those with loss of cerebellar function will also sway more with loss of visual cues.
2
Q
- An 81-year-old woman with a history of type II diabetes mellitus and atrial fibrillation presents with right body weakness and slurred speech. She realized that there was a problem on awakening in the morning, and her husband called EMS, who brought her to the emergency room. There are no word-finding difficulties, dysesthesia, or headaches. She is taking warfarin. Physical exam findings include blood pressure of 210/95 and irregularly irregular heartbeat. There is left side neglect with slurred speech. There is a corticospinal pattern of weakness of the right body, with the face and upper extremity worse than the lower extremity. Routine chemistries and cell counts are normal. Her INR is 1.7. A head CT reveals a large left-sided subdural hematoma. The intracranial material appearing most dense on computed tomography (CT) of the head is which of the following?
a. Blood clot
b. White matter
c. Gray matter
d. Cerebrospinal fluid (CSF)
e. Pia mater
A
- The answer is a. (Osborn, pp 158–159.) Computed tomographic scanning measures the density of intracranial as well as extracranial structures. Bone appears much denser than blood, but blood is obvious on the unenhanced (precontrast) CT scan precisely because it is much denser than white matter, gray matter, and CSF. The resolution of the CT scan is generally not sufficient to differentiate the pia mater from the gray matter on which it lies. Other meningeal structures, such as the dura mater, may appear denser than brain, especially if there is some calcification in the membranes.
3
Q
- A 21-year-old woman presents with right arm loss of sensation that has been progressive over a few days. Her physician is concerned that this might be some type of demylinating disorder. A relatively small plaque of demyelination, should be evident on which of the following?
a. T1-weighted MRI
b. T2-weighted MRI
c. Precontrast CT
d. Diffusion-weighted MRI
e. PET
A
- The answer is b. (Osborn, p 757.) Magnetic resonance imaging looks primarily at the water content of tissues, but it can be customized to look at specific properties of tissues. A variety of methods are available for affecting the information produced by and analyzing the information generated by MRI. The T1-weighted image enhanced by gadolinium contrast agent is useful for identifying inflammation and other causes of fluid extravasation into the brain. The T2-weighted image is not specific for demyelination, but it is useful in following changes in plaques of demyelination, an application that has been used in studies of agents useful in the management of multiple sclerosis. Magnetization transfer and other more complex techniques have been developed to look at demyelination specifically, but they are not generally available. The diffusion–weighted image technique looks at the diffusion coefficients of water molecules in tissues and is proving useful in studies of acute stroke. The CT scan cannot readily distinguish between tissues of similar densities. Positron emission tomography is primarily a research tool that is useful in determining what materials are used or are unavailable for use in specific parts of the brain.
4
Q
Items 4–6 A 62-year-old right-handed man has “involuntary twitches” of his left hand. He first noticed between 6 months and 1 year ago that when he is at rest, his left hand shakes. He can stop the shaking by looking at his hand and concentrating. The shaking does not impair his activities in any way. He has no trouble holding a glass of water. There is no tremor in his right hand and the lower extremities are not affected. He has had no trouble walking. There have been no behavioral or language changes. On examination, a left hand tremor is evident when he is distracted. Handwriting is mildly tremulous. He is very mildly bradykinetic on the left.
- The most likely exam finding would be which of the following?
a. Upper motor neuron pattern of weakness on the left
b. Lower motor neuron pattern of weakness on the left
c. Bilateral upper motor neuron pattern of weakness
d. Mild cogwheel rigidity on the left only with distraction
e. Bilateral severe cogwheel rigidity
A
- The answer is d. (Greenberg, 5/e, pp 241–243.) This patient gives a typical history for early Parkinson’s disease. The classic triad is asymmetric resting tremor, rigidity, and bradykinesia. The rigidity is generally severe later, not early in the disease. Parkinson’s disease is not characterized by weakness.
5
Q
Items 4–6 A 62-year-old right-handed man has “involuntary twitches” of his left hand. He first noticed between 6 months and 1 year ago that when he is at rest, his left hand shakes. He can stop the shaking by looking at his hand and concentrating. The shaking does not impair his activities in any way. He has no trouble holding a glass of water. There is no tremor in his right hand and the lower extremities are not affected. He has had no trouble walking. There have been no behavioral or language changes. On examination, a left hand tremor is evident when he is distracted. Handwriting is mildly tremulous. He is very mildly bradykinetic on the left.
- Tremor in the hands that is most obvious when the patient is awake and trying to perform an action is most likely due to disease in which of the following structures?
a. Thalamus
b. Cerebellum
c. Substantia nigra
d. Spinal cord
e. Internal capsule
A
- The answer is b. (Victor, p 90.) Intention or kinetic tremors are most characteristic of damage to the cerebellum. Kinetic tremors of the hand or arms are most common with disease of the cerebellar hemispheres, but they may also develop with damage to the spinocerebellar tracts of the spinal cord. Damage to the substantia nigra, such as that occurring in Parkinson’s disease, produces a resting tremor that abates when the patient moves the involved limb intentionally. Damage to the thalamus is more likely to produce a sensory disturbance. Tremors may develop with spinal cord damage, but they do not follow a typical pattern and do not suggest a spinal cord origin.
6
Q
Items 4–6 A 62-year-old right-handed man has “involuntary twitches” of his left hand. He first noticed between 6 months and 1 year ago that when he is at rest, his left hand shakes. He can stop the shaking by looking at his hand and concentrating. The shaking does not impair his activities in any way. He has no trouble holding a glass of water. There is no tremor in his right hand and the lower extremities are not affected. He has had no trouble walking. There have been no behavioral or language changes. On examination, a left hand tremor is evident when he is distracted. Handwriting is mildly tremulous. He is very mildly bradykinetic on the left.
- In the person with Parkinson’s disease, the tremor that is evident when a limb is at rest changes in what way when the patient falls asleep?
a. It becomes more rapid
b. Its amplitude increases
c. It generalizes to limbs that were uninvolved when the patient was awake
d. It disappears
e. It transforms into choreiform movements
A
- The answer is d. (Hauser, p 27.) Patients with Parkinson’s disease often have a characteristic pill-rolling tremor of the hand while they are awake. The tremors associated with Parkinson’s disease are worse when the patient is at rest and not moving the affected limb. Paradoxically, this resting tremor ceases when relaxation progresses to sleep. In fact, most tremors and other types of movement disorders caused by disease of the caudate, putamen, and globus pallidus (i.e., the basal ganglia) and of the substantia nigra remit during sleep. Choreiform movements are jumping or dancelike movements and occur with Wilson’s disease (hepatolenticular degeneration) and Huntington’s disease, a hereditary degenerative disease of the basal ganglia.
7
Q
- A 25-year-old woman with a history of epilepsy presents to the emergency room with impaired attention and unsteadiness of gait. Her phenytoin level is 37. She has white blood cells in her urine and has a mildly elevated TSH. Examination of the eyes would be most likely to show which of the following?
a. Weakness of abduction of the left eye
b. Lateral beating movements of the eyes
c. Impaired convergence
d. Papilledema
e. Impaired upward gaze
A
- The answer is b. ( Rowland, p 823.) Most rhythmic to-and-fro movements of the eyes are called nystagmus. Nystagmus has a fast component in one direction and a slow component in the opposite direction. Nystagmus with a fast component to the right is called right-beating nystagmus. Phenytoin (Dilantin) may evoke nystagmus at levels of 20 to 30 mg/dL. The eye movements typically appear as a laterally beating nystagmus on gaze to either side; this type of nystagmus is called gaze-evoked. If the patient has nystagmus on looking directly forward, he or she is said to have nystagmus in the position of primary gaze. Therapeutic levels for phenytoin are usually 10 to 20 mg/dL, and some patients develop asymptomatic nystagmus even within that range. Ataxia, dysarthria, impaired judgement, and lethargy may also occur at toxic levels of phenytoin. Many other drugs also evoke nystagmus. Weakness of abduction of the left eye, or abducens palsy, is due either to injury to the sixth cranial nerve or to increased intracranial pressure. Impaired convergence can occur normally with age or may be a sign of injury to the midbrain. Papilledema is a sign of increased intracranial pressure. Impaired upward gaze may occur in many conditions, but would not be expected to occur with a toxic phenytoin level.
8
Q
- A 75-year-old generally healthy man has noticed worsening problems maneuvering over the past 4 months. He has particular trouble getting out of low seats and off toilets. He most likely has which of the following?
a. Poor fine finger movements
b. Poor rapid alternating movements
c. Distal muscle weakness
d. Proximal muscle weakness
e. Gait apraxia
A
- The answer is d. ( Braunwald, p 2522.) With primary muscle diseases, such as polymyositis, weakness usually develops in proximal muscle groups much more than in distal groups. This means that weakness will be most obvious in the hip girdle and shoulder girdle muscles. The hip girdle is usually affected before the shoulder girdle. To get out of a low seat, the affected person may need to pull him- or herself up using both arms. Persons with more generalized weakness or problems with coordination are less likely to report problems with standing from a seated position. Poor rapid alternating movements and poor fine finger movements usually develop with impaired coordination, such as that due to cerebellar damage. With severe weakness in the limbs, patients will do poorly on these tests of function as well. With proximal muscle weakness, the affected person will usually perform relatively well on these tests of distal limb coordination.
9
Q
- A 50-year-old woman is being examined for hearing loss. A vibrating tuning fork is applied to the center of her forehead. This helps to establish which ear
a. Has the wider range of frequency perception
b. Has the larger external auditory meatus
c. Has infection of the external ear canal
d. Has the longer eustachian tube
e. Has conductive or sensorineural hearing loss
A
- The answer is e. (Victor, p 306.) The vibrations from a tuning fork placed on top of the head are transmitted through the skull to both ears. Bone conduction of sound through the skull should be equal in both ears. With sensorineural hearing loss, the patient will hear the midline fork more loudly in the unaffected ear. Sensorineural hearing loss is the deafness that develops with injury to the receptor cells in the cochlea or to the cochlear division of the auditory nerve. In conductive hearing loss, the vibrations of the tuning fork are perceived as louder in the affected ear. With this type of hearing loss, the injury is in the system of membranes and ossicles designed to focus the sound on the cochlea. Impairment of the conductive system causes the vibrations of the tuning fork to be transmitted to the cochlea directly through the skull. Much like a person with cotton stuffed into the external auditory meati, the patient with the conductive hearing loss has impaired perception of sound coming from around him or her but an enhanced perception of his or her own voice. This type of tuning fork test is called the Weber test.
10
Q
Items 10–11 A 67-year-old woman says that she is having problems with dizziness. A more careful history reveals that she has an abnormal sensation of movement intermittently.
- Which of the following tests would be most helpful in determining the cause of episodic vertigo?
a. CSF
b. C-spine MRI
c. Visual evoked response (VER)
d. Electronystagmography (ENG)
e. Electroencephalography (EEG)
A
- The answer is d. ( Bradley, pp 733–736.) ENG is used primarily to characterize nystagmus and disturbances of eye movements that involve relatively fast eye movements. Abnormal patterns of eye movement may help localize disease in the central or peripheral nervous system in patients with vertigo. The retina is negatively charged in comparison with the cornea, which creates a dipole that is monitored during ENG studies by electrodes placed on the skin about the eyes. Movement of the most posterior elements of the retina toward an electrode is registered as a negative voltage change at that electrode. Damage to the pons may produce characteristic conjugate deviations of the eyes. The conjugate eye movements are rhythmic and directed downward, but they lack the rapid component characteristic of nystagmus. This type of abnormal eye movement is called ocular bobbing. A lesion at the cervicomedullary junction, such as a meningioma at the foramen magnum, will produce a down-beating nystagmus with both eyes rhythmically deviating downward, with the rapid component of this nystagmus directed downward as well. Cervicomedullary refers to the cervical spinal cord and the medulla oblongata. Damage to the midbrain, thalamus, or hypothalamus may disturb eye movements, but down-beating nystagmus would not ordinarily develop with damage to these structures.
11
Q
Items 10–11 A 67-year-old woman says that she is having problems with dizziness. A more careful history reveals that she has an abnormal sensation of movement intermittently.
- This patient develops increased sensitivity to sound in her left ear, and a brain MRI reveals a posterior fossa mass. This symptom may develop in one ear with damage to the ipsilateral cranial nerve?
a. V
b. VII
c. VIII
d. IX
e. X
A
- The answer is b. (Victor, pp 1451–1452.) The facial nerve innervates the stapedius muscle of the middle ear. With paralysis of this muscle,undamped transmission of acoustic signals across the stapedius bone of the middle ear produces hyperacusis. Hyperacusis is an indication that the damage to the facial nerve is close to its origin from the brainstem, because the nerve to the stapedius muscle is one of the first branches of the facial nerve. The tensor tympani is controlled by the motor fibers in the fifth cranial nerve. With damage to this nerve, the tympanic membrane has some inappropriate slack, but the patient does not usually comment on increased sensitivity to sound in the affected ear.
12
Q
- A 42-year-old woman is being evaluated for gait difficulties. On examination, it is found that her ability to walk along a straight line touching the heel of one foot to the toe of the other is impaired. This finding is most common with which of the following?
a. Cerebellar dysfunction
b. Parietal lobe damage
c. Temporal lobe damage
d. Ocular motor disturbances
e. Dysesthesias in the feet
A
- The answer is a. (Greenberg, 5/e, p 104.)Walking along a straight line with the heel of one foot touching the toe of the other foot is called heel-totoe walking, or tandem gait. It is a routine test for ethanol intoxication because alcohol exposure impairs the coordination of gait as governed by the cerebellum. Tandem gait will be abnormal with many other problems, including weakness, poor position sense, vertigo, and leg tremors, but such abnormality in the absence of these other problems suggests a cerebellar basis for the problem.
13
Q
- A 55-year-old woman is being examined. The clinician notices the presence of fine twitching movements beneath the surface of the tongue and wasting of one side of the tongue. This finding suggests damage to cranial nerve?
a. V
b. VII
c. IX
d. X
e. XII
A
- The answer is e. (Greenberg, 5/e, p 360.) The hypoglossal nerve innervates the tongue. The fine movements noted under the surface of the tongue with injury to the hypoglossal nerve are called fasciculations and are an indication of denervation. They are presumed to occur through hypersensitivity to acetylcholine acting at the denervated neuromuscular junction. Atrophy and fasciculations are likely to occur together and are highly suggestive of denervation of the tongue. This is most often seen with brainstem disease, such as stroke or bulbar amyotrophic lateral sclerosis (ALS), or with transection of the hypoglossal nerve.
14
Q
- A 46-year-old longshoreman complains of lower back pain radiating down the posterior aspect of his left leg, and paresthesias in the lateral aspect of his left foot. This has been present for 6 months. Strength and bowel and bladder function have been normal. Examination would be most likely to show which of the following?
a. Left Babinski sign
b. Loss of pinprick sensation over the webspace between the first and second digits of the left foot
c. Hyperreflexia at the left knee jerk
d. Hyporeflexia in the left Achilles tendon reflex
e. Decreased rectal tone
A
- The answer is d. (Victor, pp 213–215.) This patient has a history most consistent with a herniated lumbar disk. The most common locations for lumbar disk herniation are between the fifth lumbar and first sacral vertebrae (producing S1 nerve root compression) and between the fourth and fifth lumbar vertebrae (producing L5 root compression). S1 nerve root compression, or radiculopathy, is associated with pain in the lower back or buttock region, often radiating down the posterior thigh and calf to the lateral and plantar surfaces of the foot and affecting the fourth and fifth digits of the foot. Motor function of the foot and toe flexors, toe abductors, and hamstring muscles may be impaired but more often is not. Bowel and bladder function are usually preserved. The loss of the ankle jerk, or Achilles tendon reflex, is often the only objective sign of S1 radiculopathy. Deep tendon reflexes such as the ankle jerk are diminished or lost when there is damage to the sensory fibers from the tendon stretch organs. A Babinski sign is an indication of upper motor neuron damage, which is not expected in this case with preserved autonomic and motor function. Loss of pinprick sensation over the web space between first and second toes is found in association with injury to the fifth lumbar nerve root or to the peroneal nerve. Hyperreflexia of the knee jerk is another sign of an upper motor neuron lesion and would not be expected in this case. Straight-leg raising (Lasègue maneuver) is used to determine whether symptoms are due to nerve root compression by stretching the nerve root. With compression, lifting the leg passively may be limited to between 20 and 30°. This test may be positive on the contralateral side (crossed straight-leg raising sign), but it is usually more prominent on the affected side.
15
Q
- A 28-year-old graduate student presents with confusion and mild right hemiparesis developing over the course of an evening. His girlfriend relates that he has been complaining of severe headaches each morning for the past 2 weeks. While being evaluated in the emergency room, he has a generalized tonic—clonic seizure. When examined 2 h later, he is lethargic and unable to recall recent events, has difficulty naming, and has a right pronator drift. There is mild weakness of abduction of the eyes bilaterally. Funduscopic examination might be expected to show which of the following?
a. Pigmentary degeneration of the retina
b. Hollenhorst plaques
c. Retinal venous pulsations
d. Blurring of the margins of the optic disc
e. Pallor of the optic disc
A
- The answer is d. (Victor, pp 258–260, 684–686.) The presentation with subacute onset of morning headaches culminating in confusion, right hemiparesis, and seizure in a young person suggests an expanding mass lesion, most likely a tumor. The weakness of eye abduction bilaterally is what may be referred to as a false localizing sign. Although this suggests injury to the sixth cranial nerves bilaterally, the injury is not restricted to the sixth cranial nerve. The increase in intracranial pressure (ICP) from the mass causes stretching of the sixth-nerve fibers, which consequently leads to their dysfunction. Diplopia may be appreciated only on lateral gaze, which requires full function of the sixth nerve. Funduscopic exam in such a case would most likely reflect changes of increased ICP. The first sign of this is usually blurring of the margins of the optic disc and elevation of the disc due to swelling. Changes in the optic disc—the area in which all the nerve fibers from the retina come together and exit as the optic nerve— occur with problems other than increased ICP (such as optic neuritis), but blurring of the margins should be routinely considered a sign of increased ICP. This is especially true if the appearance of the disc has changed in association with the development of headache, obtundation, and vomiting. Pigmentary degeneration of the retina may occur with some infections, such as congenital toxoplasmosis or cytomegalovirus, or as part of a hereditary metabolic disorder, as in retinitis pigmentosa. Hollenhorst plaques are cholesterol and calcific deposits seen in the retinal arterioles in the setting of atheroembolism to the eye, along with visual loss. Retinal venous pulsations are typically not present when there is increased ICP, although they may also be absent in up to 15% of normal individuals.
16
Q
- Taking a normal, awake person who is lying supine with head slightly elevated (30°) and irrigating one external auditory meatus with warm water will induce?
a. Tonic deviation of the eyes toward the ear that is stimulated
b. Nystagmus in both eyes toward the ear that is stimulated
c. Tonic deviation of the ipsilateral eye toward the ear that is stimulated
d. Nystagmus in both eyes away from the ear that is stimulated
e. Tonic deviation of both eyes away from the ear that is stimulated
A
- The answer is b. (Victor, p 319.) Caloric stimulation of the ear drives the endolymphatic fluid in the inner ear up or down, depending on whether warm or cold water is used. By tilting the head of a supine patient up 30° from the horizontal, the semicircular canal responsible for detecting horizontal head movements is placed in a vertical plane and caloric stimulation drives the endolymph in that canal more effectively than it will the endolymph in the other semicircular canals. The vestibular organ exposed to warm water sends impulses to the brainstem that indicate that the head is moving to the side that is being warmed. The eyes deviate to the opposite side to maintain fixation on their targets, but the eye movement actually breaks fixation. A reflex nystagmus toward the ear that is being stimulated develops as the brain tries to establish refixation while the vestibular signals repeatedly prompt deviation of the eyes contralateral to the warm stimulus.
17
Q
Items 17–18 A 33-year-old woman has the acute onset of right orbital pain after a tennis match. The following morning, her 10-year-old son comments that her right eye looks funny. On examination, she has a mild right ptosis and anisocoria. The right pupil is 2 mm smaller than the left, but both react normally to direct light stimulation. Visual acuity, visual fields, and eye movements are normal
- The site of injury is due to interruption of fibers from which of the following structures?
a. Optic tract
b. Optic chiasm
c. Cranial nerve III
d. T1 nerve root
e. Superior cervical ganglion
A
- The answer is e. (Victor, p 319. Kandel, p 963.) The presence of ptosis and miosis indicate oculosympathetic palsy, or Horner syndrome. This indicates injury to the sympathetic supply to the eye. This pathway begins in the hypothalamus, travels down through the lateral aspect of the brainstem, synapses in the intermediolateral cell column of the spinal cord, exits the spinal cord at the level of T1, and synapses again in the superior cervical ganglion. From there, postganglionic fibers travel along the surface of the common carotid and internal carotid artery until branches leave along the ophthalmic artery to the eye. Fibers of the sympathetic nervous system, which are destined to serve the sudomotor function of the forehead, travel with the external carotid artery. Thus, diseases affecting the internal carotid artery and the overlying sympathetic plexus do not produce anhidrosis, the third element of Horner syndrome. In this case, the occurrence of painful Horner syndrome acutely after vigorous activity is virtually diagnostic of carotid artery dissection. Dissections may occur more frequently in migraineurs. The preservation of visual fields and acuity excludes significant disease of the optic tract and chiasm, which also would not be expected to cause ptosis. Lesions of cranial nerve III (CN 3) do cause ptosis, but they would also be expected to cause ipsilateral mydriasis, or pupillary enlargement, not miosis. The degree of ptosis is usually much more severe in third-nerve palsy than in Horner syndrome; this is because CN 3 supplies the levator palpebrae, the primary levator of the lid, whereas the sympathetics supply Müller’s muscle, which plays an accessory role. The sympathetic pathway does exit the spinal cord at T1, but injury at this location would not cause orbital pain, which is typical of carotid arterial dissection.
18
Q
Items 17–18 A 33-year-old woman has the acute onset of right orbital pain after a tennis match. The following morning, her 10-year-old son comments that her right eye looks funny. On examination, she has a mild right ptosis and anisocoria. The right pupil is 2 mm smaller than the left, but both react normally to direct light stimulation. Visual acuity, visual fields, and eye movements are normal
- Magnetic resonance imaging (MRI) of the head and neck in this patient would be expected to show which of the following?
a. Increased T2 signal in a periventricular distribution
b. Contrast enhancement along the tentorial margin
c. Increased T1 signal in the wall of the right carotid artery
d. Enlarged optic nerve in the orbit
e. Thrombosed cavernous sinus aneurysm
A
- The answer is c. (Osborn, pp 234–235.) The most likely cause of this patient’s symptoms and signs is a carotid dissection. Dissections are caused by a tear in the intimal lining of the vessel with penetration of blood beneath the intimal surface, forming an intramural hematoma (blood clot within the wall of the vessel). This may be seen as an area of increased signal within the lining of the vessel on T1-weighted images, on which a blood clot appears bright. Typically, this takes a crescentic pattern, and the lumen of the vessel is displaced eccentrically. An increased T2 signal in a periventricular distribution is typical of the plaques of demyelinating disease seen in multiple sclerosis. Contrast enhancement along the tentorial margin might be seen in inflammatory diseases of the dura mater or meninges. An enlarged optic nerve might be seen in the setting of optic neuritis or infiltration of the nerve by a tumor or other process, and this would be expected to cause visual impairment. A cavernous sinus aneurysm that is sufficient to produce oculosympathetic palsy would be expected to cause other deficits in ocular motility because the cranial nerves subserving oculomotor function course through the cavernous sinus.
24
Q
Items 24–26 24. In this MRI scan, the site most likely to produce a noncommunicating hydrocephalus when it is obstructed is identified by the
a. Open black arrow
b. Straight white arrow
c. Curved black arrow
d. Black arrowhead
e. Straight black arrow
A
- The answer is a. (Osborn, p 434.) The open black arrow denotes the aqueduct of Sylvius, which connects the third ventricle with the fourth ventricle. This sagittal view of the lower part of the brain provides a highresolution view of the posterior fossa. What appears to be a connection between the most inferior aspect of the fourth ventricle and the cisterna magna (at the straight black arrow) is an artifact. This is the obex of the fourth ventricle, and there is a complete roof over this ventricle, which communicates with the subarachnoid space through the foramens of Luschka and Magendie.
25
Q
- The location of the cerebellar tonsil (t) in the MRI scan suggests?
a. Arnold-Chiari type 1 malformation
b. Arnold-Chiari type 2 malformation
c. Giant cisterna magna
d. Dandy-Walker syndrome
e. Normal posterior fossa
A
- The answer is e. (Osborn, p 18.) Bone has low signal on this T1- weighted image of the head, and so it may not be obvious that this cerebellar tonsil is sitting above the opening of the foramen magnum. The white streak just above the curved white arrow is the bone marrow in the occipital bone. With Arnold-Chiari malformations, the tonsil would be expected to sit below the foramen magnum. With Dandy-Walker syndrome or giant cisterna magna, the tonsil would be inapparent or at least sitting much more cephalad.
26
Q
- The tentorium cerebelli (curved black arrow) separates the superior cerebellum from the cerebrum and is a common site of origin for? a. Meningiomas b. Ependymomas c. Hemangioblastomas d. Medulloblastomas e. Astrocytomas
A
- The answer is a. (Osborn, p 420.) All five of the tumors listed are common in the posterior fossa. The tentorium cerebelli is a fold of meninges. Consequently, it is a relatively common site for the development of meningiomas. A tumor arising on the tentorium may extend either superiorly or inferiorly. Inferior extension of the tumor may damage cranial nerves and make complete extirpation of this benign neoplasm impossible.
27
Q
A 35-year-old woman has noticed that over the past 3 to 5 months she has had some difficulties with balance, particularly when she closes her eyes. On examination, she has decreased hearing in her left ear and also left body dysdiadochokinesia. Her physician orders a head CT. Given this CT scan, which was obtained without contrast enhancement
- the physician must assume that the posterior fossa mass at the arrow is?
a. Normal
b. Calcified
c. Highly vascular
d. Granulomatous
e. Highly cystic
A
- The answer is b. (Osborn, pp 593–594.) Calcified masses appear hyperdense without contrast enhancement, whereas highly vascular lesions may appear dense on CT scanning after the patient has received intravenous contrast material. Tumors, granulomas, and other intracranial lesions enhance because of a breakdown in the blood-brain barrier. More cystic lesions may exhibit enhancement limited to the periphery of the cyst.
28
Q
A 35-year-old woman has noticed that over the past 3 to 5 months she has had some difficulties with balance, particularly when she closes her eyes. On examination, she has decreased hearing in her left ear and also left body dysdiadochokinesia. Her physician orders a head CT. Given this CT scan, which was obtained without contrast enhancement
- If this patient noticed no vertigo, tinnitus, or hearing loss, but did exhibit slowly evolving left arm ataxia, left-sided head tilt, dysarthria, and left facial weakness, the probable explanation for this lesion would be
a. Cerebellar infarction
b. Cerebellar hemorrhage
c. Meningioma
d. Schwannoma
e. Astrocytoma
A
- The answer is c. ( Bradley, pp 1248, 1273.) Any type of stroke in the cerebellum would be expected to evolve over the course of hours, rather than days or weeks. With signs and symptoms that evolve slowly, a neoplasm is more likely. Because there was no involvement of the eighth cranial nerve and because the lesion on CT scan is calcified, the most probable neoplasm is a meningioma. This tumor also appears to arise from the petrous bone, another indication that it is most likely a meningioma.
29
Q
A 35-year-old woman has noticed that over the past 3 to 5 months she has had some difficulties with balance, particularly when she closes her eyes. On examination, she has decreased hearing in her left ear and also left body dysdiadochokinesia. Her physician orders a head CT. Given this CT scan, which was obtained without contrast enhancement
- The most appropriate course of action in managing this lesion is?
a. Anticoagulation
b. Triple therapy with isoniazid, rifampin, and ethambutol
c. Surgical resection
d. Proton beam irradiation
e. Craniospinal axis irradiation
A
- The answer is c. (Victor, pp 692–693.) Complete resection of this large meningioma is probably impractical because of the damage to cranial nerves that would be sustained with any attempt at complete extirpation. If tumor must be left behind, repeated surgery may be necessary. Chemotherapy is not helpful because these tumors are notoriously insensitive. Radiation therapy is controversial because some tumors may become more anaplastic after radiation, but the current evidence supports irradiating residual tumor.
30
Q
A 35-year-old woman has noticed that over the past 3 to 5 months she has had some difficulties with balance, particularly when she closes her eyes. On examination, she has decreased hearing in her left ear and also left body dysdiadochokinesia. Her physician orders a head CT. Given this CT scan, which was obtained without contrast enhancement
- If the patient with this lesion also exhibits café au lait spots and reports a family history of bilateral hearing loss at a relatively young age, a gene abnormality should be suspected on chromosome?
a. 5
b. 13
c. 17
d. 21
e. 22
A
- The answer is e. (Victor, p 692.) Meningiomas occur with increased frequency in type 2 neurofibromatosis, a dominantly inherited disorder arising with a deletion on the long arm of chromosome 22. Women with breast cancer and other gynecologic cancers are also at increased risk of developing meningiomas, perhaps because of sex steroid receptors on these tumors that enhance their growth when gynecologic disturbances occur. Estrogen or progesterone antagonists may be useful in the management of these tumors, but tamoxifen, an estrogen inhibitor, paradoxically stimulates the growth of meningioma cells.
31
Q
A 35-year-old woman has noticed that over the past 3 to 5 months she has had some difficulties with balance, particularly when she closes her eyes. On examination, she has decreased hearing in her left ear and also left body dysdiadochokinesia. Her physician orders a head CT. Given this CT scan, which was obtained without contrast enhancement
- Dysdiadochokinesia is an impairment of ?
a. Successive finger movements
b. Heel-to-toe walking
c. Rapid alternating movements
d. Tremor suppression
e. Conjugate eye movements
A
- The answer is c. (Victor, pp 93–94.) Dysdiadochokinesia is usually apparent with cerebellar damage. It is most evident when strength and sensation are intact. Alternately tapping one side of the hand and then the other, or tapping the heel and then alternating with the toe of the foot, is the test usually employed to check this aspect of coordination. Multiple sclerosis in adults and cerebellar tumors in children are two of many causes of problems with this part of the neurologic examination. Focal lesions in the nervous system may produce highly asymmetric dysdiadochokinesia. A variety of movement disorders, such as parkinsonism and choreoathetosis, may interfere with rapid alternating movements and give the false impression that the patient has a lesion in systems solely responsible for coordination.
38
Q
Items 38–44 For each clinical scenario, choose the CSF pattern most likely to be found.
- A 26-year-old woman with a 7-year history of epilepsy develops a generalized convulsion while shopping. She is taken to an ER, but no one accompanying her is aware of the previous history of epilepsy. Because she has a protracted postictal period, numerous investigations are performed over the course of the next hour. CT scan is completely normal, but her arterial blood gases reveal a mild acidosis. (SELECT 1 PATTERN)
A
- The answer is f. ( Bradley, p 1752.) This CSF profile is essentially normal. With idiopathic seizures, the CSF should be normal. Seizure activity does not ordinarily drive up the CSF protein content or significantly change the cellular content of the fluid. Occasionally, there is a mild pleocytosis of up to 80 cells/μL, which peaks 1 day postictally. The acidosis that is observed in this patient is inconsequential and is routinely found during the early postictal period after a generalized tonic-clonic seizure.
39
Q
Items 38–44 For each clinical scenario, choose the CSF pattern most likely to be found.
- A 72-year-old man is brought to the ER in a coma. He has a fever and was observed to have a generalized tonic-clonic seizure just prior to arriving in the ER. His family reports that he had complained of lethargy and cough about 1 week prior to the acute deterioration. On the day of his seizure, he complained of headache and blurred vision. He had some vomiting early in the day and became more stuporous as the day progressed. There is no evidence of alcohol or drug use. (SELECT 1 PATTERN)
A
- The answer is d. ( Bradley, p 1318.) This man with fever, generalized seizure, lethargy, cough, headache, blurred vision, and progressive stupor probably has an acute bacterial meningitis. Given his age of 72 and history of probable upper respiratory infection, a pneumococcal meningitis is highly probable. In bacterial meningitis, the CSF typically exhibits an elevated protein content, no or few RBCs, an elevated opening pressure, milky or xanthochromic fluid, and a normal or slightly elevated gamma globulin content. If there are relatively few white cells and the CSF protein is not greatly elevated, the fluid may appear clear and colorless. The WBC count will be elevated, and the WBCs in the CSF will consist of both polymorphonuclear cells and lymphocytes. A very low CSF glucose content supports the diagnosis of bacterial meningitis. Tuberculous meningitis, however, produces an atypical pattern of CSF changes distinct from that caused by other bacterial pathogens and reminiscent of that caused by fungi.
40
Q
Items 38–44 For each clinical scenario, choose the CSF pattern most likely to be found.
- A 19-year-old man notices discomfort in his ankles within a few days of recovering from an upper respiratory infection. Over the next 7 days, he develops progressive weakness in both of his legs and subsequently in his arms. He has no loss of sensation in his limbs, despite the progressive loss of strength. He does not lose bladder or bowel control, but on the tenth day of his weakness he develops problems with breathing and requires ventilatory assistance. (SELECT 1 PATTERN)
A
- The answer is b. (Victor, p 1382.) This young man with ascending paralysis with preserved sensation and sphincter control has Guillain-Barré syndrome. His CSF is largely normal except for its markedly high protein. The CSF is xanthochromic (i.e., yellow) because of the high protein content of the fluid. Despite the pattern of weakness, which suggests an ascending myelitis, his CSF reveals a normal cell count. That a bacterial meningitis is not responsible for his weakness is supported by a normal CSF glucose content. The CSF protein with Guillain-Barré syndrome may exceed 1 g, becoming so viscous that normal CSF flow patterns are disturbed.
41
Q
Items 38–44 For each clinical scenario, choose the CSF pattern most likely to be found.
- A 40-year-old man was involved in an automobile accident. There is an obvious laceration on his head, and he complains of neck pain. Police at the scene report that he was unconscious when they arrived, but the patient cannot recall this loss of consciousness. In fact, he cannot remember the accident or events within 10 min prior to the accident. On examination, he has obvious neck stiffness and photophobia. Within a few hours of his arrival at the ER, he develops vomiting. Lumbar puncture is delayed until after an MRI can be obtained. The tap is performed 2 days after the accident because the patient is still confused and irritable. (SELECT 1 PATTERN)
A
- The answer is g. ( Bradley, pp 550–551.) This man involved in an automobile accident, probably has subarachnoid blood associated with his head trauma. This is suggested by his neck stiffness, photophobia, and vomiting. That he had transient loss of consciousness and that there was obvious trauma to his head supports the notion that he suffered enough of a blow to his head to produce intracranial bleeding of some sort. Even if the neuroimaging studies do not reveal any contusion, he could still have a substantial accumulation of blood in the subarachnoid space from damage to vessels in the arachnoid itself. A high CSF protein content and xanthochromia suggest that much of the blood in the CSF has already broken down by the time of the tap. Many RBCs will persist for days with a substantial subarachnoid hemorrhage. The WBC count will be elevated because the subarachnoid blood is irritating and produces a chemical meningitis. The opening pressure may be slightly elevated if there has been much bleeding into the subarachnoid space.
42
Q
Items 38–44 For each clinical scenario, choose the CSF pattern most likely to be found.
- A 22-year-old woman is brought to the hospital in a coma. She has had changes in her behavior characterized by excessive suspiciousness and facetiousness over the month prior to her hospitalization. One week prior to her hospitalization, she had visual and auditory hallucinations. Drug testing reveals no apparent illicit drug use. On the day of admission, she had a generalized seizure and lapsed into a coma. MRI shows unilateral changes in the temporal lobe. (SELECT 1 PATTERN)
A
- The answer is e. ( Bradley, pp 1358–1359.) This young woman with progressive behavioral disturbances, hallucinations, seizures, and obtundation probably has a herpes simplex type 1 encephalitis. The CSF with herpes simplex encephalitis often has some RBCs in addition to the primarily mononuclear increase in WBCs. The CSF protein is elevated, but the glucose content is relatively normal with this viral infection. As the CSF protein increases, the percentage that is gamma globulin generally increases. This is not an indication that the problem is an infection, but this increase in total protein and gamma globulin component does occur with infections. The opening pressure may be markedly elevated, but the fluid may remain clear or be only slightly cloudy if the white blood cell count does not increase substantially.
43
Q
Items 38–44 For each clinical scenario, choose the CSF pattern most likely to be found.
- A 26-year-old man develops bed wetting and transient sexual dysfunction that resolves over the course of 6 weeks. One month later, he notices a pins-and-needles sensation in his right leg that never clears completely. On examination, he has hyperreflexia in both of his legs and pastpointing in his right arm. His gait is slightly ataxic, and he is unable to perform tandem gait. (SELECT 1 PATTERN)
A
- The answer is c. (Rowland, p 782.) This young man has signs and symptoms of multiple sclerosis that are largely referable to the spinal cord. Gait ataxia is an especially common presenting complaint. Impotence is troublesome and common. The CSF fluid picture is distinctive in its elevation of the gamma globulin content. Oligoclonal banding studies of the fluid would most likely be positive.
44
Q
Items 38–44 For each clinical scenario, choose the CSF pattern most likely to be found.
- A 26-year-old woman weighing in excess of 300 lb complains of headache and blurred vision that began 2 weeks prior to consulting a physician. She has no vomiting or diplopia. Examination of her eyes reveals florid papilledema but without hemorrhages. Her neurologic examination is otherwise entirely normal. She had a similar problem while pregnant with her fourth child. (SELECT 1 PATTERN)
A
- The answer is a. ( Bradley, pp 1552–1553.) This woman with headaches, papilledema, and slightly blurred vision probably has pseudotumor cerebri. This idiopathic increase in intracranial pressure usually occurs in obese young women, during pregnancy, or with hypervitaminosis. The extraordinarily high CSF opening pressure associated with pseudotumor cerebri does not produce herniation of the brain, and performing a spinal tap does not place the patient at increased risk for transforaminal herniation. The CSF glucose content, protein content, cell count, and gamma globulin studies in persons with pseudotumor cerebri should all be unremarkable.
