Peripheral Nerve Cases
Chief Complaint
34-year-old female with right arm pain and weakness
History of Chief Complaint:
Patient complains of right arm pain and weakness following a fall off a horse 1 hour ago. She says that she was wearing a helmet and just fell off, directly onto a log as she was jumping with the horse. Patient says her arm (points to humeral area) does not look normal and she is in a significant amount of pain. She says it hurts too much to move her elbow, but she can move her fingers and bend her wrist although she is unable to straighten her wrist to normal. She also complains of strange tingling on the back of her right hand. Patient denies hitting her head, loss of consciousness, injury/pain in neck or back, or loss of bowel/bladder function
Medical History:
Tonsillectomy at age 8. Left radial fracture and left femur fracture after falling off horse 3 years ago.
Vitals: BP=138/88 Pulse=96 RR= 14 Temp = 99.1 SpO2 = 98% on RA
Physical Exam:
Young appearing female in mild distress secondary to pain is rubbing her right arm in the sling. Head is atraumatic normocepahilc. C-collar is in place but patient denies any pain or tenderness to gentle palpation. Fundoscopic exam reveals sharp disc margin, AV ratio 3 to 4. ENT is normal; TM is pearly gray without hemotympanum, No battle signs. Lung sounds are clear to auscultation and present throughout all lung fields. Heart is regular rate and rhythm with no murmurs, rubs, or gallops. Abdomen is soft, nontender, non-distended, without evidence of trauma, and no organmegaly. Negative Grey Turner sign. Pelvis is stable. Obvious deformity to right humeral region 10-15cm superior to the lateral epicondyle. No deformities noted in the left upper extremity or lower extremities. Patient is tearful secondary to pain
Neurologic Exam:
Mental Status: Alert and oriented x3. Speech is meaningful but slow. Follows multistep commands.
Cranial Nerves: Visual fields are intact with PERRLA and EOMI bilaterally. Sensation is intact throughout face and jaw jerk reflex is normal. Corneal reflexes are normal bilaterally. Facial movements are full and symmetric. Hearing is normal and symmetric bilaterally. Gag reflex is intact and uvula is on midline. Shoulder shrug strong and equal bilaterally. Tongue protrudes on midline.
Motor: Right wrist flexion is intact. Patient cannot extend the wrist. Fasciculations are present in the skin on the posterior forearm. All five digits can abduct and adduct appropriately and patient can make a fist. Motor exam is normal in other extremities.
Sensory: Right upper extremity sensory is intact except diminished sensation to pinprick, touch and 2 point discrimination over the back of the hand and extensor surface of first four digits. Otherwise normal sensorium.
Coordination/Gait: Heel to shin tests within normal limits. Negative Romberg.
Follow Up:
Humeral fracture required surgical intervention for fixation and management of a developing hematoma. After cast removal, the profound weakness in her wrist movements remained from the injury. She also noticed that her right wrist tended to “flop” into a different position than her left wrist at rest. She says physical therapy has helped with her other movements but her wrist remains weak. Repeat physical exam indicated 5/5 muscle strength throughout RUE except wrist extension 0/5 and elbow flexion 4+/5. Decreased muscle mass of posterior compartment of forearm on the right compared to the left. DTRs are 2/4 at biceps and triceps, but 0/4 at brachioradialis. Negative Hoffman sign. Sensorium is unchanged from prior visit.
Questions
1) The motor deficit seen in this patient would best be classified as
a. Spastic Paralysis
b. Motor Ataxia
c. Dyskinesia
d. Flaccid Paralysis
e. Clonus
ANSWER
2) The motor weakness identified in flexion of the elbow on follow up can most likely be explained through lack of innervation to
a. Brachialis
b. Brachioradialis
c. Biceps Brachii
d. Anconeus
e. Triceps Brachii
ANSWER
3) The sensory modalities lost in this patient are normally carried by the
a. Anterolateral System and Corticospinal Tract
b. Spinocerebellar Tract and Corticospinal Tract
c. Cuneate fasciculus and Spinocerebellar Tract
d. Cuneate fasciculus and Anterolateral system
e. Cuneate fasciculus and Corticospinal tract
ANSWER
4) The sensory deficit distribution seen in this patient is most consistent with the
a. Superficial Radial Nerve
b. C6 Dermatome
c. Posterior Cutaneous Nerve of the Forearm
d. C7 Dermatome
ANSWER
5) Chromatolytic cell bodies would most likely be located in
a. Intermediolateral cell column
b. Cuneate nucleus
c. Primary Motor Cortex
d. Dorsal root ganglia
e. Lateral Horn
ANSWER
6) Wallerian degeneration can be observed in
a. Posterior Interosseous Nerve
b. Cuneate Fasciculus
c. Anterolateral System
d. Dorsal Rootlets
e. Ventral Rootlets
ANSWER
7) The most likely location of this lesion in the neuraxis is
a. Spinal nerve
b. Spinal Roots
c. Spinal Cord
d. Brachial Plexus
e. Peripheral Nerve
ANSWER
8) The best description of the distribution of this process at initial presentation is
a. Focal
b. Multifocal
c. Diffuse
ANSWER
9) The best description of the temporal profile of this neurologic process is
a. Acute and stable
b. Acute and progressive
c. Insidious and stable
d. Subacute and stable
ANSWER
10) The etiology of this patient’s condition is best characterized as
a. Infectious
b. Traumatic
c. Vascular
d. Neoplastic
e. Degenerative
ANSWER