**2. Diagnostic criteria of SIH**

The diagnostic criteria used to verify the SIH cases are on shown on Table 1.

The clinical presentations and radiological findings may vary. Diagnosis is largely based on clinical suspicion, cranial MR findings and myelographic detection of dural leak. The posi‐ tional characteristics of the headache should always be questioned in patients admitting with meningeal irritation signs. Orthostatic headache, characteristic imaging features on MRI and instantaneous improvement of symptoms with a successful blood patch are key points of differential diagnosis from viral meningoencephalitis or other causes of aseptic meningitis syndrome.


**Table 1.** Diagnostic Criteria for Headache Due to Spontaneous Spinal CSF Leak and Intracranial Hypotension According to the International Classification of Headache Disorders, 2nd Ed42 (4)
