What is the best course of action for a middle-aged adult patient with no significant past medical history, presenting with orthostatic headaches (worsening when laying down or bending over), accompanied by dizziness and nausea, with normal computed tomography (CT) and magnetic resonance imaging (MRI) scans?

Spontaneous Intracranial Hypotension (SIH) - Proceed with Contrast-Enhanced MRI Brain and Spine

Your patient's presentation of headache worsening when lying down or bending over with dizziness and nausea, despite normal standard CT and MRI, is highly suspicious for spontaneous intracranial hypotension (SIH), and you must immediately order MRI brain WITH IV contrast plus whole spine MRI to detect the characteristic findings of CSF leak. 1

Why Standard Imaging Was Normal

• Standard non-contrast CT and MRI have limited sensitivity for detecting the subtle findings of intracranial hypotension, particularly early in the disease course or in cases with atypical presentations 1
• The characteristic diagnostic findings of SIH require contrast-enhanced imaging to visualize pachymeningeal enhancement, which is the most sensitive finding 1

Critical Next Steps in Diagnostic Workup

Immediate Imaging Protocol Required

• Order MRI brain WITH IV contrast to look for diffuse pachymeningeal enhancement (the most sensitive finding for SIH) 2, 1
• Include whole spine MRI to identify the site of CSF leak 2
• Add MR venography to rule out cerebral venous thrombosis (CVT), which can develop as a life-threatening complication of SIH and presents with similar symptoms 1

Key Imaging Findings to Identify

• Diffuse pachymeningeal enhancement (most sensitive finding) 2, 1
• Brain sagging with descent of brainstem and flattening of pons 1
• Subdural fluid collections or small subdural hematomas 2, 1
• Venous sinus engorgement as a compensatory mechanism 1

Life-Threatening Complication to Exclude

• Cerebral venous thrombosis (CVT) can develop as a complication of SIH and is life-threatening, requiring urgent diagnosis 1
• CVT presents with headache that worsens in recumbent position as intracranial pressure rises 1
• Most CVT patients appear neurologically normal initially (altered mental status occurs in only 8% of cases), so normal neurological exam does not exclude this diagnosis 1
• If CVT is identified, immediate anticoagulation is indicated even in the presence of small subdural collections 1

Treatment Algorithm Once SIH is Confirmed

First-Line Conservative Management (72 hours)

• Strict bed rest with head elevated as comfortable 2
• Aggressive hydration 1
• Caffeine supplementation 1
• Appropriate pain relief with paracetamol and/or NSAIDs; avoid long-term opioids 2

Definitive Treatment if Conservative Measures Fail

• Epidural blood patch (EBP) is the definitive treatment if conservative measures fail after 72 hours 2, 1
• Target the blood patch at the level of the identified CSF leak when possible 1
• Thromboprophylaxis should be considered during immobilization following EBP according to local venous thromboembolism policy 2

Post-Procedure Management

• Patients should lie flat as much as possible for 1-3 days after the procedure 2
• Minimize bending, straining, stretching, twisting, closed-mouth coughing, sneezing, heavy lifting, and strenuous exercise for 4-6 weeks 2
• Patients should be advised to seek urgent medical attention for new-onset severe back or leg pain, lower limb motor weakness, sensory disturbance, urinary or fecal incontinence, urinary retention, perineal sensory disturbance, nausea and vomiting, or fever 2

Long-Term Monitoring Considerations

• If the patient remains symptomatic despite treatment, consider evaluation for orthostatic intolerance with head-up tilt table testing, as patients with SIH can develop persistent autonomic dysfunction 3
• Patients with SIH should have MRI of the brain including blood-sensitive sequences (SWI or GRE) to detect superficial siderosis, a potential long-term complication 2
• Higher index of suspicion is needed in patients who develop ataxia, hearing loss, or myelopathic features, which may indicate superficial siderosis 2

Common Pitfalls to Avoid

• Do not accept normal standard CT/MRI as ruling out SIH - contrast-enhanced imaging is essential for diagnosis 1
• Do not delay MR venography - CVT is a life-threatening complication that can present with similar symptoms and requires urgent anticoagulation 1
• Do not assume neurological normalcy excludes serious pathology - most CVT patients appear neurologically normal initially 1
• Do not pursue empirical epidural blood patch without proper imaging confirmation - while some advocate for this approach, proper imaging should guide targeted treatment 2, 1