What is the best course of action for a patient with a mildly elevated INR, taking methocarbamol, who presents with dizziness and headaches after a recent fall, especially when considering the potential for a concussion or other head injury?

Immediate CT Head Imaging is Mandatory

This patient requires urgent non-contrast CT head imaging to rule out intracranial hemorrhage, given the mildly elevated INR (1.43), recent head trauma with loss of consciousness implied by the mechanism, and persistent neurological symptoms. 1

Critical Risk Assessment

Elevated Bleeding Risk with Anticoagulation

• An INR of 1.43, while only mildly elevated, significantly increases the risk of delayed intracranial hemorrhage following head trauma 1
• Patients with even therapeutic-range anticoagulation (INR 2.0-3.0) have a 40% increased odds of intracranial hemorrhage after head trauma and double the mortality risk 1
• The 2-3 day delay since injury falls within the critical window for delayed hemorrhage presentation 1

High-Risk Clinical Features Present

• Mechanism of injury: Fall with impact to back of head, right shoulder, and upper back suggests significant force 1
• Persistent symptoms: Ongoing dizziness and headaches 2-3 days post-injury are concerning for evolving intracranial pathology 2, 3
• Orthostatic component: Dizziness worsening with position changes could indicate either vestibular injury OR decreased cerebral perfusion from evolving mass effect 2, 4

Immediate Management Algorithm

Step 1: Neuroimaging (Do Not Delay)

• Obtain non-contrast CT head immediately 1
• Do not wait for "worsening symptoms" - the current presentation warrants imaging 1
• Document any focal neurological deficits on examination before imaging 1

Step 2: If CT Shows Intracranial Hemorrhage

• Admit to hospital immediately 1
• Stop methocarbamol (contributes to dizziness and CNS depression) 5
• Do NOT use intravenous vitamin K - this can cause rapid INR correction and paradoxically increase thrombotic risk in the setting of mild elevation 1
• Allow INR to normalize gradually by withholding any anticoagulants (if patient is on warfarin, which is not stated but possible given the elevated INR) 1
• Consider fresh frozen plasma only if INR >6.0 or active bleeding progression 1
• Neurosurgical consultation for any significant hemorrhage 1

Step 3: If CT is Negative for Hemorrhage

• Repeat CT in 24 hours is reasonable given the elevated INR and persistent symptoms, as delayed hemorrhage can occur 1
• Proceed with vestibular evaluation for post-concussive dizziness 2, 4

Differential Diagnosis for Dizziness (After Hemorrhage Excluded)

Most Likely: Benign Paroxysmal Positional Vertigo (BPPV)

• BPPV is the most common vestibular diagnosis after head trauma, occurring in 61% of post-traumatic dizziness cases 6
• The positional component (worse when standing from sitting/lying) is classic for BPPV 1, 2
• Perform Dix-Hallpike maneuver to diagnose posterior canal BPPV 1
• If positive, treat with canalith repositioning maneuvers (Epley maneuver) 1

Other Peripheral Vestibular Causes

• Labyrinthine concussion: Direct trauma to inner ear structures 2, 4
• Perilymph fistula: Less common but possible with significant head impact 2
• Post-traumatic endolymphatic hydrops: Can develop weeks after injury 2

Central Vestibular Causes

• Only 8% of post-traumatic dizziness cases show central vestibular abnormalities 6
• Would expect additional neurological signs (dysarthria, ataxia, diplopia, sensory changes) if brainstem/cerebellar injury present 1

Vestibular Migraine

• Can develop after concussion and presents with episodic vertigo lasting minutes to hours 1, 4
• Associated with photophobia, phonophobia, or visual aura 1
• Consider migraine prophylaxis if this pattern emerges 4

Methocarbamol Contribution

Drug Effects Mimicking or Worsening Symptoms

• Methocarbamol commonly causes dizziness, lightheadedness, drowsiness, and vertigo as listed adverse reactions 5
• CNS depression from methocarbamol may impair compensation mechanisms for vestibular injury 5
• Consider discontinuing or reducing dose once acute pain from musculoskeletal injury improves 5

Critical Pitfalls to Avoid

Do Not Assume "Just Concussion" Without Imaging

• The combination of elevated INR + head trauma + persistent symptoms mandates imaging regardless of normal vital signs 1
• Normal GCS does not exclude intracranial hemorrhage in anticoagulated patients 1

Do Not Attribute All Dizziness to Concussion

• 88% of patients with post-traumatic dizziness have identifiable audio-vestibular abnormalities on testing 6
• Failure to diagnose and treat BPPV leads to prolonged disability when simple repositioning maneuvers could provide immediate relief 1, 6

Do Not Overcorrect Mildly Elevated INR

• INR 1.43 does not require reversal agents unless active bleeding occurs 1
• Aggressive reversal increases thrombotic risk 1

Follow-Up Plan (After Hemorrhage Excluded)

Within 24-48 Hours

• Formal vestibular testing if symptoms persist: videonystagmography, rotary chair testing, vestibular evoked myogenic potentials 2, 6
• Audiometry to assess for high-frequency sensorineural hearing loss (present in 53% of post-traumatic dizziness) 6

Falls Risk Assessment

• This patient has already fallen once; 12-fold increased fall risk exists with symptomatic dizziness 1
• Assess home safety and support systems 1
• Consider physical therapy for vestibular rehabilitation if peripheral vestibular dysfunction confirmed 2, 4

Expected Timeline

• Most post-concussive symptoms resolve by 3-6 months 3
• BPPV can be treated immediately with repositioning maneuvers 1
• Persistent symptoms beyond 6 months warrant re-evaluation for other causes 3, 4