67yM PMH HTN, HLD, gastritis, MI s/p stent on prasugrel, chronic low back pain presents with RUE weakness s/p fall. Patient exacerbated his back pain a week ago and has been mostly resting in bed since. This evening, he was taking a hot bath and when he stood up and started to feel lightheaded and then lost consciousness. He fell backwards striking the left side of his head. He estimates he was unconscious for 3 minutes. He denies tongue biting, urinary incontinence, or seizure history. When he woke up, he felt slightly confused, and noted that he was unable to use his right upper extremity normally. He now has difficulty lifting his right arm with some slight tingling in the shoulder radiating down the lateral aspect. He denies pain.
PMH / PSH
PMHx: As above
PSHx: Coronary stent x 5 years ago
Meds: Effient, Lisinopril, Atorvastatin, Zetia, Pantoprazole
VS: Temp 97.7 BP 113/77 HR 75 RR 20 SpO2 98% on RA
Gen: Well appearing man in C-collar in NAD
HEENT: Left forehead hematoma with approximately 3cm overlying abrasion. PERRLA, EOMI, no hemotympanum, no blood in the oropharynx, no battle sign or raccoon eyes
CV: RRR, S1/S2, no chest wall crepitus
Abd: Soft, nondistended, nontender
RUE: Normal bulk and tone. Shoulder shrug WNL. Deltoid strength 3-4/5, Bicep strength 4/5, Tricep strength 5/5. Grip strength 5/5. Firing AIN/PIN/IO. SILT
LUE: 5/5 strength throughout. SILT
Neuro: A+Ox3. CN grossly intact. No dysmetria. Normal finger to nose. Normal rapid alternating movements. No pronator drift. Normal gait.
CBC: 14.0 > 16.8 / 50.6 < 226
BMP: 140 / 3.9 / 106 / 23 / 17 / 0.9 < 134
LFT: AST 28 ALT 24 Alk Phos 96 TBili 0.9 DBili 0.2
PT/INR: 14.1 / 1.26
Troponin < 0.015
- Left frontal scalp hematoma and soft tissue swelling. No acute intracranial abnormality
- No facial bone fracture
- No acute cervical spine fracture or subluxation
Based on history and exam is this more likely a central or peripheral lesion?
The patient presented with unilateral right sided weakness more pronounced in the upper arm with lateral arm sensory deficits. A unilateral finding in an isolated area, sparing distal nerve distributions would be more suspicious of a peripheral lesion. The central nervous system consists of the brain cortex and spinal cord while the peripheral nervous system encompasses peripheral nerve roots as they exit the vertebral column. A central brain lesion could present with unilateral weakness and numbness however the expectation would be that it would it not spare distal function in the arm. The patient had full strength and sensation distal to the elbow. A direct cord injury or transection would result in flaccid motor paralysis at the level of the injury with resulting loss of motor function in all caudal levels as well as a decrease in sensation and proprioception in the next level and beyond. A central cord injury with damage to the spinal grey matter typically involves the upper extremities initially in a classic "cape like distribution", however again the expectation would be to have bilateral findings. A disk herniation or spondylolisthesis at a unilateral nerve root could present with unilateral neurological findings like with this patient.
If it is central, where would the expected lesion be? If it is peripheral, what dermatome levels are affected?
If this were a central brain lesion we would expect the lesion to be near the central portions of the left frontal and parietal lobes as this is where the motor and sensory fibers for the upper extremity are. Vascular lesions would arise from either the distal anterior or middle cerebral artery. A deep penetrating lacunar infarct could also present with unilateral arm numbness and weakness. A peripheral lesion could be predicted by looking at the dermatome and myotome maps for a human. A lesion at C5 - C6 would impair flexion of the bicep, abduction of the arm above the shoulder (deltoid) as well as present with parenthesis on the lateral aspect of the arm.
What imaging test would you order next?
Given that the patients clinical picture points to either a peripheral lesion or central disk herniation, the appropriate test to order next would be an MRI of the cervical spine. For this particular patient, the MRI revealed a hyper intense signal at the right lateral recess at C5 extending into the C5 and C6 foramina consistent with a traumatic spinal cervical epidural hematoma. Traumatic spinal cervical epidural hematomas are relatively rare and usually seen after procedural manipulation. It can be seen after minor trauma like with this patient, and has a higher incidence rate among patients on anticoagulation. Management is prompt neurosurgical evaluation and evacuation to prevent long term neuropraxia.