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Case 2
HISTORY AND PHYSICAL EXAMINATION
Right buttock pain developed in a 67-year-old man, radiating to the lateral thigh
and pretibial area. The pain worsened when he walked. Within a few weeks, he became
aware of right foot weakness with partial footdrop. There had been no sensory
symptoms. He did not respond to conservative therapy and was referred for an
electrodiagnostic (EDX) examination. Past medical history was otherwise
negative.
On neurological examination, the patient had moderate weakness of right foot
and toe dorsiflexion, and ankle eversion and inversion (Medical Research
Council [MRC] 4− /5) and severe weakness of right large toe dorsiflexion (MRC 3/5).
Plantar flexion was minimally weak (MRC 5− /5). Deep tendon reflexes were normal
except for trace ankle jerks bilaterally. Sensory examination revealed relative impairment
of pain sensation over the dorsum of the foot. Straight leg raise was negative.
The patient’s gait was impaired by the partial right footdrop.
QUESTIONS
1. The EMG findings are diagnostic of:
A. A lumbosacral plexopathy.
B. An L5 more than S1 radiculopathy due to a herniated disc at the L5–S1
space.
C. An L5 more than S1 radiculopathy due to a herniated disc at the L4–L5
space.
D. A sciatic neuropathy.
E. An L5 more than S1 radiculopathy.
2. All of the following findings are consistent with an S1radiculopathy except:
A. Fibrillation potentials in the abductor hallucis.
B. Fibrillation potentials in the medial head of the gastrocnemius.
C. Fibrillation potentials in the flexor digitorum longus.
D. Fibrillation potentials in the gluteus maximus.
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E. Absent sural sensory nerve action potentials (SNAPs).
3. In an L5 radiculopathy of about 6 months’ duration, which muscle is likely to show the
most amount of fibrillation potentials?
A. Biceps femoris (short head).
B. Extensor hallucis longus.
C. Gluteus medius.
D. Lumbar paraspinal muscles.
E. Tensor fascia lata.
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Case 8
HISTORY AND PHYSICAL EXAMINATION
A 36-year-old man underwent mitral valve replacement for rheumatic heart
disease. On awakening from general anesthesia, he noted weakness of the right foot
and numbness of the dorsum of the foot. He had no pain. His footdrop did not improve,
and he was referred to the electromyography (EMG) laboratory 5 weeks after the
onset of footdrop.
On examination, there was a near-complete right foot and toes drop (Medical
Research Council [MRC] strength 1/5). Foot eversion was markedly weak (3/5), but
inversion and plantar flexion were normal. Deep tendon reflexes, including ankle jerk,
were normal. There was sensory impairment to touch, and pin sensation over the
dorsum of the right foot. Tinel sign was negative on percussion of the right peroneal
nerve at the fibular neck. The rest of the neurologic examination was normal.
.
QUESTIONS
1. Based on the nerve conduction studies only, the lesion is likely:
A. Axonal.
B. Demyelinating.
C. Mixed, demyelinating and axonal.
D. Undetermined until the needle EMG is completed.
2. The most common precipitating factor for this type injury, when acute, is:
A. Leg crossing.
B. Weight loss.
C. Diabetes mellitus.
D. Recent general anesthesia and surgery.
E. Underlying peripheral polyneuropathy.
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3. The most common precipitating factors for this type of injury, when subacute or
chronic, are:
A. Weight loss.
B. Diabetes mellitus.
C. Diabetes mellitus and underlying peripheral polyneuropathy.
D. Recent prolonged hospitalization.
4. The prognosis for recovery of footdrop in this patient is:
A. Poor because of prominent fibrillation potentials.
B. Poor because of the near absence of voluntary motor unit potentials.
C. Favorable and biphasic, with anticipated early rapid improvement and some
delayed recovery.
D. Poor, because of very low proximal peroneal compound motor action
potential (CMAP) amplitudes recording tibialis anterior and the extensor
digitorum brevis.
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Case 12
HISTORY AND PHYSICAL EXAMINATION
During an automobile repair, the right arm of a 23-year old man was pinned
under a car for 2 to 3 minutes when the jack came off accidentally. Immediately, he
noticed a right wristdrop. There were no lacerations or bruises. Radiographs of the right
arm and forearm were normal. The wristdrop improved slightly over the next few weeks.
He was referred to the electromyography (EMG) laboratory 5 weeks after the incident.
On examination, there was severe weakness of the right wrist extensors, all finger
extensors, and the brachioradialis (Medical Research Council [MRC] 2/5), with intact
finger and wrist flexors, biceps, triceps, and deltoid muscles. He had impairment of pain
and touch sensation over the dorsum of the hand. The right brachioradialis reflex was
absent. All other deep tendon reflexes were normal. The rest of the neurological
examination was normal. EMG examination was done 5 weeks postinjury.
QUESTIONS
1. The clinical and electrodiagnostic (EDX) findings are consistent with:
A. Lower cervical radiculopathy.
B. Posterior cord brachial plexopathy.
C. Posterior interosseous mononeuropathy.
D. Radial mononeuropathy in the arm.
2. All the following muscles are innervated by the posterior interosseous nerve except:
A. Extensor digitorum profundus.
B. Extensor indicis proprius.
C. Extensor carpi ulnaris.
D. Abductor pollicis longus.
E. Extensor carpi radialis longus.
3. Common causes of this injury include all of the following except:
A. Midhumeral fracture.
B. “Saturday night palsy.”
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C. Occupational use with repetitive wrist movements.
D. Strenuous muscular effort.
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Case 16
HISTORY AND PHYSICAL EXAMINATION
Acute, severe right upper extremity pain developed overnight in a 22-year-old
man; it peaked in 2 days, resulted in multiple visits to the emergency room, and
ultimately led to admission to a community hospital on the third day. The pain was deep
and maximal around the right shoulder, with radiation to the arm and forearm, and
did not worsen with coughing or sneezing. Three to four days after admission, while the
patient was being treated with analgesics, he noted weakness of the right upper
extremity. The weakness was maximal in the shoulder and arm, and much less severe in
the hand. He had slight numbness in the hand and forearm, most particularly in the right
thumb. He was given a 10-day course of oral prednisone and was referred to a tertiary
care center.
Two weeks before the onset of pain, the patient had an upper respiratory tract
infection with cough, nasal discharge, fever, and malaise. This was treated with
antibiotics for one week. There was no history of trauma. He was otherwise in excellent
health. When the patient was seen 4 weeks after the onset of symptoms, he had minimal
shoulder pain. Cranial nerve examination was normal. There was no Horner sign.
Findings were limited to the right upper extremity, where there was complete
loss of function of the right deltoid, spinati, biceps, and brachioradialis (Medical
Research Council [MRC] 0/5). The right triceps was much less involved (4/5). There was
mild diffuse weakness of all finger and wrist extensors, with severe weakness of the
right thumb long flexion (flexor pollicis longus) and distal interphalangeal flexion of the
index and middle fingers (flexor digitorum profundus). This resulted in a positive pincer
or OK sign (Figure C16–1). Deep tendon reflexes of the right upper limb were absent.
Sensation revealed mild sensory loss over the thumb, and lateral arm and forearm.
An electrodiagnostic (EDX) study was performed.
QUESTIONS
1. The clinical and EDX findings suggest that most of the insult involves the following two
nerves:
A. Ulnar and radial nerves.
B. Medial cord and anterior interosseous nerve.
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C. Upper trunk and anterior interosseous nerve.
D. Lateral cord and radial nerve.
2. The aforementioned disorder has the following characteristics except:
A. It is more frequent in males.
B. It is sometimes preceded by upper respiratory tract infection or vaccination.
C. It is typically painful at onset.
D. It sometimes is bilateral and rarely recurrent.
E. It is restricted to the neural elements of the brachial plexus.
3. The routine motor nerve conduction study results in this disorder may be normal
because:
A. The illness is not associated with significant axonal loss.
B. The lesion involves frequently the upper trunk of the brachial plexus.
C. The process is demyelinating.
D. All of the above.
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Case 17
HISTORY AND PHYSICAL EXAMINATION
A 21-year-old woman developed intermittent binocular diplopia, primarily with distant
vision. Within a few weeks, the symptoms worsened and she noted droopy eyelids, first
on the right, then on the left. She had increasing fatigue and weakness, primarily after
activity, and had fallen a few times. On system review, she admitted to fatigue and
weakness while chewing but denied swallowing and speech difficulties. All symptoms
improved after rest. The patient was otherwise in excellent health. On examination, the
patient was alert, oriented, and in no distress. She had mild bilateral ptosis, which
worsened with sustained upgaze. Extraocular muscles showed bilateral lateral rectus
muscle weakness with nystagmoid movements on lateral gaze. Pupils and fundi were
normal.
There was mild bilateral peripheral facial weakness and weakness of eye
closure. Speech, tongue, and palate were normal. The patient had moderate weakness
in the limb muscles particularly in the legs and worse proximally. Her outstretched arms
became fatigued in 1 to 2 minutes and could not be sustained. Deep tendon reflexes
throughout. Sensation and coordination were normal. Gait was slow and
waddling. Romberg test was negative. Tensilon (Edrophonium) test was equivocal, with
possible improvement of ptosis only. An electrodiagnostic (EDX) examination was
performed.
QUESTIONS
1. Decremental response on slow repetitive stimulation is commonly seen in all of the
following except:
A. Botulism.
B. Amyotrophic lateral sclerosis.
C. Myasthenia gravis.
D. Corticosteroid myopathy.
E. Lambert-Eaton myasthenic syndrome (LEMS).
2. In patients with suspected ocular myasthenia, which test is most sensitive in
establishing the diagnosis?
A. Serum acetylcholine receptor antibody.
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B. Single-fiber jitter study of the frontalis muscle.
C. Slow repetitive stimulation of the facial nerve.
D. Slow repetitive stimulation of the spinal accessory nerve.
E. Single-fiber jitter study of the extensor digitorum communis.
3. Factors that increase the sensitivity of electrodiagnosis in myasthenia gravis include
all of the following except:
A. Slow repetitive stimulation, recording weakened muscles.
B. Slow repetitive stimulation before and after exercise.
C. Rapid repetitive stimulation, recording a proximal muscle.
D. Single-fiber EMG jitter study.
E. Slow repetitive stimulation on warm limbs
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Case 19
HISTORY AND PHYSICAL EXAMINATION
Progressive weakness developed over 7 months in the left hand of a 53-year-old
right-handed woman. Initially, she noted that she had difficulty picking up small objects,
buttoning shirts, or pulling snaps. This worsened and she recently has been unable to
use her left hand to assist during meals. The weakness had not affected her left upper
arm and her right upper extremity was normal. She denied any limb or neck pain,
numbness, or cramps. She denied any bulbar, ocular, cognitive, or sphincteric
symptoms.
Her medical history was relevant for diabetes mellitus since 45 years of age,
hypertension, and cigarette smoking. She takes insulin injections and furosemide. There
is no family history of neuromuscular disorder. On examination, she had normal mental
status and cranial nerves. There was no facial weakness, neck weakness, or tongue
atrophy or fasciculations. She had slight atrophy of all intrinsic muscles of the left hand
only. No fasciculations were observed. Tone was normal. There was moderate
weakness that was restricted to the left upper extremity muscles. Manual muscle
examination, using Medical Research Council (MRC) grading (1 to 5), showed the
following:
Hand grip 4− /5
Interossei 4− /5
Long finger flexors 4/5
Long finger extensors 4/5
Elbow flexion 5− /5
Elbow extension 5− /5
Shoulder abduction 5− /5
Deep tendon reflexes were pathologically brisk in both upper extremities, but
knee jerks were normal and ankle jerks were absent. Jaw jerk was brisk. She had a
right Babinski sign and bilateral Hoffmann signs. Sensory examination was normal to all
modalities. Results of gait and cerebellar examinations were normal.
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The patient was evaluated by a neurologist who found normal x-rays of the cervical
spine. Magnetic resonance imaging of the cervical spine revealed mild disk bulging at
C3–C4 and C5–C6. An electrodiagnostic (EDX) study of the left upper extremity, done 3
months after onset of symptoms, revealed fibrillations and large motor units in left
C7-, C8-, T1-innervated muscles, with normal sensory and motor nerve conduction
studies. Because of progressive left hand weakness, the patient was referred for a
repeat EDX examination 7 months after the onset of symptoms.
QUESTIONS
1. The aforementioned EDX findings can be seen with all of the following except:
A. Widespread polyradiculopathy.
B. Diffuse anterior horn cell disease.
C. Axonal motor neuropathy.
D. Diabetic distal polyneuropathy.
2. Diffusely low-amplitude compound muscle action potentials (CMAPs) may be caused
by all of the following except:
A. Cool limbs.
B. Amyotrophic lateral sclerosis (ALS).
C. Duchenne muscular dystrophy.
D. Lambert-Eaton myasthenic syndrome.
E. Widespread polyradiculopathy.
3. In a patient with diffuse degenerative spine disease, the presence of fibrillations in the
upper and lower limbs, as well as the tongue and masseter muscles, is diagnostic
of ALS:
A. True.
B. False.
4. A patient with weakness in the right hand has fibrillation potentials in the right C5
through T1 roots, with normal left upper limb, lower limbs, thoracic paraspinal and
bulbar muscles. These findings rule out ALS:
A. True.
B. False.
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Case 20
HISTORY AND PHYSICAL EXAMINATION
A 32-year-old white woman developed progressive weakness in the legs over 2
months. She noticed gradually increasing difficulty climbing stairs and standing from a
sitting position. She began using a walker for assistance 4 days before admission to the
hospital. She reported muscle pain in both legs but denied any ocular, bulbar, or
sphincteric symptoms. There was no history of skin rash or arthralgia. Three weeks
earlier, she was found to have “abnormal liver function tests” and received a diagnosis
of possible “toxic hepatitis.” She was taking no medications and denied any history of
alcohol or drug abuse.
On examination, she was in no apparent distress. There was no skin rash. She
had normal cranial nerves. She had significant difficulty getting up from a chair and
needed assistance when walking. There was generalized mild muscle tenderness.
Manual muscle examination revealed significant symmetrical proximal more than distal
muscle weakness, worse in the legs. Deep tendon reflexes were normal. Sensation was
normal. Using the Medical Research Council (MRC) grading system, her muscle
strength was rated as follows:
Right Left
Deltoid 4/5 4/5
Triceps 4/5 4/5
Biceps 4/5 4/5
Hand grip 4
Iliopsoas 4− /5 4− /5
Quadriceps 4− /5 4− /5
Hamstrings 4− /5 4− /5
Abnormal laboratory values were: creatine kinase (CK)
14 857 units/liter (U/L) (normal, 140 U/L), aldolase 589.1 U/L
(normal, 3.5–17.5 U/L), lactate dehydrogenase (LDH)
1475 U/L (normal, 60–210 U/L), serum alanine aminotransferase
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(ALT) 478 U/L (normal, 8–54 U/L), and serum aspartate
aminotransferase (AST) 566 U/L (normal, 10–50 U/L).
Normal laboratory studies included the following: Westergren erythrocyte
sedimentation rate (ESR; 10 mm/h), serum gamma-glutamyl transferase (GGT) level,
antinuclear antibody (ANA), rheumatoid factor, thyroxine (T4), thyroid stimulating
hormone (TSH), complete blood count (CBC), bilirubin, alkaline phosphatase,
electrolytes, and serum protein electrophoresis. Negative results included the following:
human immunodeficiency virus (HIV) antibody, urine myoglobin, serum lyme titers,
toxoplasma immunoglobulin M (IgM) and Venereal Disease Research Laboratory
(VDRL). An electrodiagnostic (EDX) examination was performed.
QUESTIONS
1. In this disorder fibrillation potentials are most common in:
A. Paraspinal muscles.
B. Proximal muscles of the lower extremities.
C. Proximal muscles of the upper extremities.
D. Distal muscles.
E. Anterior neck muscles.
2. Motor unit action potentials (MUAPs) seen in the chronic form of this disorder are:
A. Short in duration and low in amplitude.
B. Long in duration and complex.
C. Normal.
D. All of the above.
3. Increasing weakness developed in a 45-year-old woman with polymyositis who was
taking corticosteroids. Which of the following findings suggests steroid myopathy rather
than relapsing polymyositis?
A. Rising CK.
B. Fibrillation potentials.
C. Short-duration, low-amplitude MUAPs.
D. Complex repetitive discharges.
E. Normal insertional activity.
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Case 23
HISTORY AND PHYSICAL EXAMINATION
Fever, malaise, and sore throat developed in a 55-year-old woman who was
otherwise in excellent health. She was treated with antibiotics and analgesics. Six days
later, she first noticed that her legs had “buckled” underneath her. That afternoon, she
had difficulty climbing steps and became aware of tingling in both hands. She awoke
the next morning and could not stand. She was brought to the hospital and was
admitted. Apart from a diuretic for mild hypertension, she was taking no other
medications. On physical examination, the patient was afebrile and in no apparent
distress. She had normal vital signs, including blood pressure, pulse, and respiration.
Neurologic examination revealed normal mental status and cranial nerves. Motor
examination was relevant for weakness of the neck flexors (Medical Research Council
[MRC] 4
pelvic muscles (MRC 3/5), and the shoulder muscles (MRC
4− /5). Distally, she performed much better (5− /5). Deep tendon reflexes were absent
throughout. Sensory examination was normal, except for mild impairment of touch and
pin sensation in both hands. She was unable to sit or stand independently. An
electrodiagnostic (EDX) examination was performed 3 days after admission and 6 days
after the onset of neurologic symptoms. This was repeated later, on the 12th day after
admission, which corresponded to day 15 from the onset of neurologic symptoms.
Needle electromyography was not performed due to the acute nature of the symptoms.
QUESTIONS
1. The following features make the diagnosis of Guillain-Barr้ syndrome (GBS) doubtful
except:
A. Asymmetrical weakness.
B. Well-demarcated sensory level.
C. Severe and persistent bowel and bladder dysfunction.
D. Less than 10 mononuclear cells/mm3 in the cerebrospinal fluid (CSF).
2. Common EDX patterns in GBS include:
A. Normal nerve conduction studies.
B. Low compound muscle action potential (CMAP) amplitudes.
C. Conduction blocks and slowing of distal latencies.
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D. All of the above.
3. The best EDX predictor of poor neurological outcome in GBS is:
A. The presence of fibrillation potentials.
B. Low mean CMAP amplitude.
C. Slowing of conduction velocities.
D. Decreased recruitment of voluntary motor unit action potentials (MUAPs).
สิ่งที่ต้องทำ
1. อ่านกรณีศกึ ษาแลวตอบคาถาม
2. จากกรณีศกึ ษา ใหนักศึกษาบอกว่าผูป่ วยเป็ นโรคใด พรอมเหตุผลประกอบ
3. ใ ห review อ า ก า ร , อ า ก า ร แ ส ด ง , EDx, treatment โ ด ย discuss
กับเพื่อนในกลุม่ และอาจารย์ประจากลุม่
4. ใหทารายงานและเตรี ยมตัวนาเสนอกรณีศกึ ษาในการเรี ยนครัง้ ต่อไป
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