What are the next steps for an elderly male patient with persistent dizziness after a normal computed tomography (CT) scan, following a head injury?

Persistent Dizziness After Head Trauma with Normal CT: Next Steps

For an elderly male with persistent dizziness after head trauma and a normal CT scan, obtain an MRI brain without contrast and perform a comprehensive vestibular examination including the HINTS test and Dix-Hallpike maneuver to identify the underlying cause. 1

Why CT is Insufficient

• CT head has very poor sensitivity (20-40%) for detecting causative pathology in persistent dizziness and misses most posterior circulation infarcts, which are the most common central cause of dizziness. 1
• The risk of deterioration with both normal CT and neurologic examination is very low (0.006%), but this does not exclude all causes of persistent symptoms. 1
• Routine repeat CT in the presence of a normal initial CT and absence of neurologic deterioration is generally not recommended, with intracranial complications occurring in only 0.04% of cases within 72 hours. 1

MRI is the Appropriate Next Imaging Study

• MRI brain without contrast is indicated for persistent neurologic deficits that remain unexplained after head CT, with a diagnostic yield of 4-12% compared to <1% for CT. 1
• MRI is more sensitive than CT for subtle findings adjacent to the calvarium or skull base (small cortical contusions and subdural hematomas) and for small white matter lesions in traumatic or diffuse axonal injury. 1
• MRI with diffusion-weighted imaging is far superior to CT for detecting posterior circulation pathology that could explain persistent dizziness. 1, 2

Essential Bedside Vestibular Testing

• The HINTS examination (Head Impulse, Nystagmus, Test of Skew) has 100% sensitivity for detecting posterior circulation stroke when performed by trained practitioners—more sensitive than early MRI. 1, 3
• Perform the Dix-Hallpike maneuver to definitively rule out benign paroxysmal positional vertigo (BPPV), which is present in 34% of elderly dizzy patients and causes 36.3% of persistent dizziness cases in this population. 1, 3, 4
• The supine roll test should also be performed to evaluate for horizontal canal BPPV. 3

Consider Multiple Contributing Causes

• In elderly patients with persistent dizziness, 49-66% have more than one contributory cause, requiring a systematic evaluation of all potential etiologies. 5, 6, 4
• Cardiovascular disease is the most common major cause (40-57% of cases), followed by peripheral vestibular disease (14-22%), and neurological disease (19%). 5, 6
• Adverse drug effects contribute to dizziness in 20-23% of elderly patients—review all medications, particularly antihypertensives, sedatives, anticonvulsants, and psychotropic drugs. 5, 6

Postconcussive Syndrome Evaluation

• 58% of mild traumatic brain injury patients have persistent symptoms at 1 month post-injury, including dizziness, headache, nausea, and cognitive problems. 1
• Patients with headache, nausea, and dizziness in the emergency department have a 50% chance of developing postconcussive syndrome at 6 months. 1
• Educational information about postconcussive symptoms should be provided, as this can reduce long-term complaints. 1

Red Flags Requiring Urgent Evaluation

• New severe headache different from baseline, focal neurological deficits, sudden hearing loss, inability to stand or walk, or downbeating nystagmus mandate immediate imaging and neurologic consultation. 1, 3
• Unilateral or pulsatile tinnitus, asymmetric hearing loss, or progressive neurologic symptoms require MRI brain without contrast. 1, 3

Management Algorithm

1. Order MRI brain without contrast within the next few days 1
2. Refer to neurology or vestibular specialist for HINTS examination and comprehensive vestibular assessment 3, 7
3. Perform Dix-Hallpike and supine roll test to rule out BPPV 3
4. Review all medications for potential adverse effects causing dizziness 5, 6
5. Assess for orthostatic hypotension and cardiovascular causes 5, 6
6. If BPPV is confirmed, perform canalith repositioning procedures (Epley maneuver) with 80-98% success rate 3
7. If vestibular migraine is suspected (headache, photophobia, phonophobia), initiate migraine prophylaxis rather than vestibular suppressants 3, 7
8. If symptoms persist despite treatment, refer for vestibular rehabilitation therapy, which significantly improves gait stability in elderly patients 3

Common Pitfalls to Avoid

• Do not assume a normal CT excludes all serious pathology—75-80% of patients with acute vestibular syndrome from posterior circulation infarct have no focal neurologic deficits. 3
• Do not rely on the patient's description of "spinning" versus "lightheadedness"—focus instead on timing, triggers, and associated symptoms. 1, 3
• Do not order routine repeat CT without clinical deterioration, as the yield is extremely low (0.04%). 1
• Do not use vestibular suppressants like meclizine for chronic dizziness, as they can worsen balance and delay vestibular compensation—they should only be used for acute peripheral vertigo for 2-3 days maximum. 8