What is the appropriate management for a patient with a 3-day history of headache, dizziness, and changes in vision, who experiences worsening symptoms with neck flexion and has tachycardia, but no fever?

Urgent Neuroimaging Required for Suspected Subarachnoid Hemorrhage or Meningitis

This 67-year-old patient requires immediate non-contrast head CT followed by lumbar puncture if CT is negative, as the clinical presentation strongly suggests subarachnoid hemorrhage (SAH) or meningitis based on multiple red flags including neck pain with flexion, vision changes, vomiting, tachycardia, and progressive symptoms over 3 days. 1, 2

Critical Red Flags Present

This patient meets multiple criteria from the Ottawa SAH Rule requiring urgent investigation: 1, 2

• Age ≥40 years (patient is 67) 2
• Neck pain or stiffness (pain with neck flexion while lying down) 1, 2
• Progressive headache pattern (3-day worsening course requiring frequent analgesics) 2, 3
• Vision changes (indicates possible increased intracranial pressure or vascular pathology) 2
• Headache awakening from sleep or positional changes (temporary relief with vomiting suggests increased ICP) 1, 2

The tachycardia (HR 105) without fever further raises concern for a serious intracranial process rather than infection alone. 1

Immediate Diagnostic Algorithm

Step 1: Non-Contrast Head CT (Within 1 Hour)

Obtain emergent non-contrast head CT as the first imaging study. 1, 2, 3 Since the patient presents >6 hours from initial symptom onset (3 days of symptoms), CT sensitivity for SAH decreases, making subsequent lumbar puncture mandatory if CT is negative. 1

Step 2: Lumbar Puncture if CT Negative

If CT shows no hemorrhage, immediately proceed to lumbar puncture for xanthochromia evaluation and CSF analysis. 1, 2 The LP should be performed >6 hours from symptom onset to allow xanthochromia development. 1 This patient's 3-day symptom duration satisfies this requirement.

Do not skip LP based on negative CT alone - CT sensitivity for SAH is only 98.7% within 6 hours and decreases significantly after that timeframe. 1 Given this patient's presentation beyond 6 hours with high clinical suspicion, LP is essential. 1

Step 3: CSF Analysis Priorities

Analyze CSF for: 1

• Cell count and differential (CSF leukocyte count has 0.95 area under curve for bacterial meningitis diagnosis) 1
• Xanthochromia (for SAH detection) 1
• Opening pressure (elevated in meningitis or intracranial hypertension; low in spontaneous intracranial hypotension) 1
• Gram stain and culture (bacterial meningitis can present without fever) 1

Key Differential Diagnoses to Rule Out

Subarachnoid Hemorrhage (Primary Concern)

The combination of progressive headache, neck pain with flexion (meningismus), vision changes, and vomiting strongly suggests SAH. 1, 2 The Ottawa SAH Rule demonstrates 100% sensitivity when these criteria are met. 1

Bacterial Meningitis (Secondary Concern)

Despite absence of fever, bacterial meningitis remains possible - not all patients present with classic fever, headache, and neck stiffness triad. 1 The 67-year-old age increases risk for Streptococcus pneumoniae and Listeria monocytogenes. 1

Spontaneous Intracranial Hypotension

The positional component (pain with neck flexion while lying down, temporary relief with vomiting) could suggest intracranial hypotension from CSF leak. 1 However, this typically presents with orthostatic headache (worse upright, better lying down), which contradicts this patient's lying-down exacerbation. 1

Critical Management Pitfalls to Avoid

Do not delay imaging for lumbar puncture - obtain CT first to rule out mass effect or hemorrhage before LP. 1 However, CT should not delay antibiotic administration if bacterial meningitis is strongly suspected. 1

Do not assume migraine in this age group - new-onset headache after age 50 is a red flag mandating aggressive workup for secondary causes. 2, 3 The American College of Radiology identifies age 68 as high-risk requiring immediate neuroimaging. 3

Do not rely on absence of fever to exclude meningitis - fever is not universally present in bacterial meningitis, particularly in elderly or immunocompromised patients. 1

Do not perform LP if CT shows mass effect - the ESCMID guideline specifies that severely altered mental status (GCS <10), focal neurologic deficits, new-onset seizures, or severe immunocompromise warrant CT before LP to assess for herniation risk. 1 This patient does not meet these criteria for delaying LP if CT is negative.

If Initial Workup is Negative

Should CT and LP both be negative, consider: 3

• MRI brain with and without contrast (superior for detecting posterior fossa lesions, venous sinus thrombosis, or small infarcts) 3, 4
• MR venography (cerebral venous thrombosis can present with progressive headache and vision changes) 1
• ESR and CRP (temporal arteritis in this age group, though typically presents with temporal tenderness) 3

The tachycardia without orthostatic symptoms makes postural orthostatic tachycardia syndrome (POTS) unlikely as a primary diagnosis. 5