What is the recommended initial diagnostic imaging for a patient presenting with dizziness, headache, and nosebleed: head CT with or without contrast (Computed Tomography)?

Head CT Without Contrast is the Recommended Initial Imaging for Dizziness, Headache, and Nosebleed

For a patient presenting with the triad of dizziness, headache, and nosebleed, obtain a non-contrast head CT first to rapidly exclude hemorrhage, which is the most critical time-sensitive diagnosis in this clinical scenario. 1, 2, 3

Rationale for Non-Contrast CT as First-Line Imaging

• Non-contrast head CT is the gold standard for detecting acute hemorrhage (subarachnoid, intracerebral, or subdural), which must be excluded immediately given the combination of headache and nosebleed that could indicate intracranial bleeding with epistaxis as a secondary manifestation. 3

• The American College of Radiology guidelines emphasize that CT head without contrast allows rapid evaluation of intracranial structures and has high sensitivity for acute hemorrhage, making it the appropriate emergency department imaging modality. 1, 3

• Nosebleed (epistaxis) combined with headache raises concern for conditions like hypertensive emergency, coagulopathy, or vascular malformations that could present with both intracranial and nasal bleeding—all rapidly assessed by non-contrast CT. 3

Why Contrast is NOT Needed Initially

• There is no relevant literature supporting the use of IV contrast CT (with or without) for the initial evaluation of dizziness with headache. 1

• Contrast administration would delay diagnosis and is unnecessary for detecting the most critical pathology (hemorrhage) in this presentation. 1, 3

• IV contrast is only indicated for specific suspected diagnoses (such as venous thrombosis or vascular malformations) that would be considered after hemorrhage is excluded. 4, 5

Clinical Decision Algorithm

Step 1: Obtain Non-Contrast Head CT Immediately

• Rule out intracranial hemorrhage, mass effect, and acute structural lesions that could explain the symptom triad. 1, 3
• This imaging can be completed within minutes in the emergency setting. 3

Step 2: If CT is Negative, Consider Clinical Context

• For isolated dizziness without neurologic deficits, the diagnostic yield of CT is very low (<1%), but the addition of headache and nosebleed changes the clinical picture and justifies initial CT. 1, 2

• If the patient has focal neurologic deficits or abnormal HINTS examination (head impulse, nystagmus, test of skew), this suggests central vertigo and warrants MRI brain without contrast as the next step if CT is negative. 1, 2

Step 3: Consider Additional Imaging Based on Initial CT Results

If CT shows no acute findings:

• MRI brain without IV contrast is the preferred follow-up imaging if symptoms persist or worsen, as it has superior sensitivity (4% diagnostic yield vs <1% for CT) for detecting posterior circulation infarcts, which account for 70% of positive findings in dizziness. 2, 6

• MRI detects posterior fossa ischemic strokes that CT misses, with CT sensitivity as low as 10% for these lesions. 1

If vascular pathology is suspected after initial CT:

• CTA head and neck may be considered if there is concern for vertebrobasilar insufficiency, dissection, or aneurysm, though the diagnostic yield in isolated dizziness with normal neurologic exam is low (approximately 3%). 4, 5, 7

• One meta-analysis found that CTA identified vascular abnormalities in 7.4% of patients with acute severe headache and normal CT, but most were incidental aneurysms; only 1.6% had findings clearly related to symptoms. 5

Critical Pitfalls to Avoid

• Do not delay imaging for "medical stabilization" when there is concern for intracranial hemorrhage—this can worsen outcomes. 3

• Do not order MRI as the initial test in this acute presentation with potential hemorrhage, as it takes too long and the patient may be too unstable. 3

• Do not assume the nosebleed is purely a local ENT problem—it may be a manifestation of systemic hypertension, coagulopathy, or intracranial pathology. 3

• Do not routinely add CTA to every dizziness evaluation, as the number needed to scan to find a clinically significant abnormality (other than incidental aneurysm) is 61. 5

• Be aware that posterior fossa strokes are easily missed on CT, so maintain a low threshold for MRI if clinical suspicion remains high despite negative CT. 1, 6

When Imaging May Not Be Needed

• If the clinical picture clearly indicates benign paroxysmal positional vertigo (BPPV) with typical positional triggers and no red flags, imaging is not required. 2

• If symptoms are consistent with vestibular neuritis (acute persistent vertigo with normal neurologic exam and peripheral HINTS findings by a trained examiner), imaging may not be necessary. 1, 2

• However, the addition of headache and nosebleed to dizziness represents atypical features that warrant imaging to exclude secondary causes. 2

Evidence Quality Considerations

• The 2024 ACR Appropriateness Criteria for Dizziness and Ataxia provides the highest quality guideline evidence for this clinical scenario. 1

• Recent comparative effectiveness research (2023) demonstrates that MRI identifies more clinically significant findings than CT with CTA in dizziness patients (10.1% vs 4.7%), leading to more frequent changes in stroke prevention medication and lower 90-day ED readmission rates. 6