Objective:

To analyze the available evidence on patients with spontaneous intracranial hypotension (SIH) presenting with an initial brain MRI without typical findings, comparing their features with MRI-positive cases and evaluating diagnostic and therapeutic outcomes.

Approach:

• Search Strategy: A comprehensive search of PubMed/Medline, Web of Science, and Scopus was conducted to identify relevant studies, following PRISMA guidelines.
• Eligibility Criteria: Included studies had to report on patients with SIH or CSF hypotension without typical brain MRI findings, be peer-reviewed, and provide original data on diagnosis, treatment, and outcomes.

Key Findings:

• A substantial minority of patients with SIH may present with normal brain MRI findings.
• Patients with MRI-negative SIH share core clinical symptoms with MRI-positive cases but often have longer symptom duration and higher recurrence rates.
• Advanced imaging techniques such as CT myelography, MR myelography, and digital subtraction myelography are crucial for identifying occult CSF leaks.
• Epidural blood patch treatment may provide clinical benefit in selected patients, while surgical repair of identified leaks can lead to significant clinical improvement.

Interpretation:

In patients with suggestive clinical presentations of SIH, the absence of typical brain MRI findings should not exclude the diagnosis, indicating the need for further diagnostic evaluation.

Limitations:

• Variability in definitions of MRI negativity, imaging protocols, and diagnostic thresholds across studies may affect the interpretation of results.
• The systematic review may not encompass all relevant studies due to exclusion criteria.

Conclusion:

Further diagnostic evaluation is essential for patients with clinical presentations suggestive of SIH, even in the absence of typical brain MRI findings.

Sources:

• Systematic Review Registration