Chapter 26. Hemiplegia and Monoplegia Flashcards
Question 26-1:
Which clinical findings suggest L5 radiculopathy?
1. Weakness of extensor hallucis longus
2. Weakness of flexion of the big toe
3. Loss of sensation on the dorsum of the foot
4. Decreased ankle reflex
Select: A = 1.2,3. B = 1.3. C = 2. 4. D = 4 only. E = All
Answer 26-1: B.
The L5 nerve root innervated the extensor
hallucis longus. Weakness of this muscle is
the most sensitive and specific finding of L5
radiculopathy. The dermatomal distributions
of sensory loss are variable, but in general,
sensory loss. when present. are on the dorsum
of the foot. Toe flexion is served by intrinsic
muscles of the foot which are supplied by the
S I nerve root. The ankle reflex is also
predominantly mediated by S I. No reflex
abnormalities are common from L5
radiculopathy.
Question 26-2:
What is the most likely diagnostic consideration in a patient with arm pain plus weakness of the finger and wrist flexors and interossei?
A. C8 radiculopathy from cervical spondylosis
B. Radiation plexitis
C. Mononeuropathy multiplex
D. Tumor infiltration of the brachial plexus
Answer 26-2: D.
Weakness of the median-innervated froger and
wrist flexors plus weakness of the ulnarinnervated
intrinsic muscles suggests a single lesion at the brachial plexus. Tumor can infiltrate the brachial plexus, typically from a cancer at the superior pole of the lung, or from lymph node involvement by systemic tumor. This type of tumor is typically quite painful. C8 radiculopathy would be unlikely to
produce a profound deficit. Radiation plexitis
usually affects the upper plexus rather than the
lower plexus, because of lesser attenuation in
the superior plexus by surrounding tissues. This type of plexopathy is usually painless, in contrast to tumor infiltration. Mononeuropathy multiplex can produce ipsilateral median and ulnar neuropathies, but when median neuropathy is a component of mononeuropathy multiplex, the involvement is commonly distal to the innervation of the long flexors
Question 26-3:
Subcortical cause for hemiparesis is suggested by which of the following clinical findings?
1. Aphasia
2. Approximately equal weakness of armand leg
3. Neglect
4. Pure motor deficit, i.e, no sensory loss
Select: A = 1.2,3. B = 1.3. C = 2,4. D = 4 only. E = All
Answer 26-3: C.
Cortical lesions typically produce sensory as well as motor symptoms, since there is not defined separation of the motor and sensory regions, supplied by different arterial branches. Therefore, pure-motor deficit suggests a subcortical infarction. in the internal capsule. basal ganglia, or brainstem. Since the subconical tracts lack the topographic organization of the cerebral cortex, the weakness spans the arm and leg, approximately equally. Signs of cortical dysfunction are distinctly absent with subcortical infarction, so aphasia (expected with dominant hemisphere cortical lesions) and neglect (expected with non-dominant hemispbere cortical lesions) are absent
Question 26-4:
Deficits which appear peripheral but which cannot be explained by one anatomical localization could be explained by which of the following?
1. Multiple sclerosis
2. Vasculitis
3. Brain metastases
4. Mononeuropathy multiplex
Select: A= I, 2, 3. B = 1,3. C =2,4. D=4only. E=AII
Answer 26-4: D.
Mononeuropathy multiplex produces multifocal signs which are referable to the PNS but not CNS. Important causes of mononeuropathy multiplex include diabetes and vasculitis which can also produce central signs, however. Multiple sclerosis is the prototypic disorder to produce signs that
cannot be explained by a single CNS lesion. However, this diagnosis is more secure if there is also temporal discrepancy of the neurologic symptoms and signs. In some patients. with vasculitis and multiple metastases, PNS involvement may cause mixed central and peripheral findings
Question 26-5:
All of the following features suggest a central rather than peripheral etiology for arm weakness except which?
A. Finger coordination affected more than strength
B. Increased arm tendon reflexes
C. Pronator drift
D. Absence of sensory deficit
Answer 26-5: D.
Sensory deficit is variable in both central and
peripheral lesions. With some cortical and subcortical lesions, the involvement of sensory systems may be so mild that the motor findings eclipse any sensory findings. With some peripheral lesions. sensory fmdings may be minimal. especially radial neuropathies, anterior interosseus syndrome, and very distal ulnar neuropathy, after sensory supply to digits 4 and 5 has separated.. The other findings are present in patients with central lesions rather than peripheral lesions. Two of the prime clinical features differentiating central from peripheral lesions are coordination and tendon reflexes. Central lesions produce coordination deficit out of proportion to weakness. Central lesions also produce increase in the tendon reflexes of affected muscles, opposite that expected in
patients with peripheral lesions. Pronator drift is a specific examination finding which presumes that the limb has the power to be extended.
Question 26-6:
Left hemiparesis from a cortical lesion, such as MCA CVA, would be expected to produce
all of the following findings. except:
A. Deltoid weakness more prominent than hand intrinsic muscle weakness
B. Deficits in visuo-spatial orientation
C. Depression
D. Left hemianopia
E. Neglect
Answer 26-6: A.
With hemiparesis or monoparesis from cerebral cortical lesions, distal muscles are usually affected more prominently than proximal muscles, especially for the arm. With MCA lesions, proximal muscles of the leg may be more affected than distal muscles because the vascular supply to the proximal leg overlaps between MCA and ACA, whereas cortex serving the lower leg is clearly
in the ACA distribution
Question 26-7: A patient presents with acute onset of right leg weakness and is found on examination to have weakness of the proximal right arm. Which is the most likely diagnosis? A. Multiple sclerosis B. Anterior cerebral artery infarction C. Parasagittal meningioma D. Encephalitis
Answer 26-7: B.
Anterior cerebral artery infarction usually results in infarction of the medial aspect of the hemisphere, mainly of the frontal lobes. Contralateral leg weakness is expected. Weakness of proximal arm muscles may also be seen but the face and hand are unaffected
Question 26-8:
A patient presents with sudden onset of bilateral leg weakness along with bladder
incontinence. There is no pain and arm function is normal except for some deltoid and biceps weakness. Reflexes are hyperactive in the legs with upgoing plantar responses. Which is the most likely diagnosis?
A. Anterior cerebral artery infarction
B. Cervical spondylitic myelopathy
C. Anterior spinal artery syndrome
D. Basilar artery thrombosis
Answer 26-8: A.
Anterior cerebral artery infarction can produce bilateral leg weakness ifboth ACAs arise from the same trunk. The bilaleral leg weakness along with bladder incontinence can easily be mistaken for myelopathy. Cervical spondylosis would not normally have an abrupt onset and deltoid and biceps weakness would not be expected frow cervical myelopathy without also having distal arm
weakness
Question 26-9:
An 8-year-old female presents with episodes of unilateral weakness and stiffness which partially resolve. Multiple episodes affecting either side result in accumulation of corticospinal deficit. MRI and MRA are normal. Which is the most likely diagnosis?
A. Multiple sclerosis
B. Alternating hemiplegia of childhood
C. Vasculitis
D. Cardiogenic emboli from PFO
E. Conversion reaction
Answer 26-9: B.
Alternating hemiplegia of childhood is a rare
condition where patients develop episodes of
hemiparesis which may change sides between
attacks. Most patients develop symptoms by
the age of 4, but they continue. Multiple episodes result in cumulative neurologic deficits for many patients. Multiple sclerosis would be unusual at this age, and MRl would show white matter changes on flair and T2-weighted imaging. Vasculitis and cardiogenic emboli would also be expected to produce MRl abnormalities, with diffusion-weighted
imaging changes with acute infarction and flair and T2-weigbted image abnormalities with chronic ischemic change. Conversion reaction is extremely uncommon in young children, so the negative MRI should not cause this errant diagnosis to be made
Question 26-10:
Which of the following are most likely to produce the spinal hemisection (Brown-Sequard) syndrome?
1. Intradural tumor
2. Cervical disc disease
3. Trauma
4. Extradural tumor
Select: A = 1,2,3. B = 1, 3. C = 2, 4. D = 4 Duly. E = All
Answer 26-10: B.
The spinal hemisection syndrome is rarely
seen in pure form and usually consists of
hemiparesis sparing the face. The weakness is
ipsilateral to the lesion whereas loss of pain
and temperature sensation is contralateral 10
the lesion, Position sense may be affected
ipsilateral to the lesion.
