Neuro Defecits Post MVC

Hx: 60 yo male presents by EMS post MVC. According to EMS, the patient drove off the road and into a grove of trees. Another driver witnessed the accident and called EMS from the scene. There is no reported loss of consciousness however, the patient was noted to be altered by EMS and a trauma activation was made from the scene. He arrives in the emergency department without complaint but confused regarding events and amnestic to the car accident. Additionally, he recounts that he had some left arm tingling this morning when he woke up. He denies any neck or back pain and denies chest or abdominal injury. EMS notes there was only front end damage to the vehicle and it appeared minimal. Airbags did deploy and the witness noted the patient was restrained.

PMHs: peripheral artery disease, hypertension, “pre-diabetes”

SocHx: regular smoker, regular user of alcohol

Exam:
• Vital Signs: Pulse 110, BP 190/100, RR 18, Temp 98.6 F (37 C), O2sat 100% RA
• Head: no signs of trauma or scalp injury
• Neck: supple, no tenderness, normal range of motion without pain
• ENT: TM’s clear, eye movements intact, pupils normal and reactive bilaterally, normal pharynx
• Res: clear bilaterally, no distress
• Cardiovascular: tachycardic, regular, normal peripheral pulses
• Abdomen: soft, non-tender, no masses, non-distended
• Extremities: no deformity, warm, normal bones and joints
• Neuro: Awake, alert, amnestic to events with mild confusion, cranial nerves intact except for hemianopia on the left – unable to count fingers or see anything in left visual field, subjective decreased sensation left arm and cannot perform finger to nose with the left arm. Coordination, motor, and strength intact in right arm and bilateral legs.

Differential: 
• ICH, SDH, EDH
• dissection (vertebral)
• CVA
• cervical injury with radiculopathy
• intoxication (drugs, illicit substance)
• peripheral nerve injury, neuropraxia
• intra-cranial tumor

ED Course: 
• The patient’s clinical presentation is noted to be inconsistent with the minor vehicle damage reported by EMS. Given patient’s complaint of arm tingling on awakening and neuro defect pattern, suspicion for CVA is heightened.
• CT brain shows evidence for right PCA territory ischemic changes of the occipital lobe, additional ischemia is noted in the right MCA territory as well.
• A CT angiogram/perfusion study of the head and neck  confirms the ischemic areas and notes normal vasculature without evidence for dissection.
• CXR, EKG, and labs do not demonstrate any abnormalities.
• Consultation with neurology confirms patient is not a candidate for thrombolytics due to his time of onset on awakening and not at time of motor vehicle accident.

Hospital Course: 
• On admission, the patient receives an MRI confirming ischemia noted on CT and increasing suspicion for embolic stroke due to multiple vessel distribution of infarcts.
• Cardiac monitoring is normal
• An implanted loop recorder is placed to continuously assess patient’s rhythm after discharge
• Aspirin and Plavix are initiated
• The patient is untimely discharged to rehab for continued therapy.

Diagnosis: Embolic Ischemic Stroke, Right PCA and MCA territory infarcts. 

Discussion: This case highlights the difficulty overcoming anchoring bias. The patient’s initial presentation was that of trauma due to a motor vehicle collision. However, despite evidence from the scene of relatively minor damage, the patient had significant defects. Activation of the trauma protocol lead to immediate response but his clinical exam was noted to be inconsistent with a trauma injury pattern. Continued examination and diagnostics confirmed the presence of a medical illness (CVA) that lead to the motor vehicle collision. Thorough physician examination without bias becomes important in cases where there is a large amount of information given prior to initial examination of the patient. In these instances, anchoring bias can be difficult to overcome, and misdiagnosis can easily occur.

Ischemic Posterior Communicating Artery Stroke (PCA stroke) is a presentation that varies from the more common middle cerebral artery stroke. Symptoms of PCA stroke can include:
• vision loss
• confusion
• headache, typically posterior
• extremity weakness
• dizziness
• nausea
• memory loss
• speech difficulties
The differential diagnosis for these presentation typically includes thrombotic and embolic events in addition to traumatic lesions such as sub-dural and epileptics-dural hematomas. Though rare, intracranial masses can present in this manner as well. Among CVA’s, 20% occur in the PCA distribution. The most common cause is occlusive disease of the vertebral artery system, which can include atherosclerotic disease or dissection. Dissection of the vertebral artery is a common cause of PCA stroke presentations, with involvement of the proximal portion of the vessel in the neck being the most common location. The most common complaint is dizziness but this is typically accompanied by other symptoms.

References:

Medscape – PCA strokes

Up-To-Date – PCA strokes

Disclaimer

De-identificaiton is undertaken utilizing the Safe Harbor method described by the US Department of Health and Human Services. All remaining patient information required for teaching purposes has been altered to maintain this standard.

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