Smith raised a relevant point in response to our article.1 The International Classification of Headache Disorders (ICHD) requires the presence of either or both low CSF pressure (<60 mm CSF) and evidence of CSF leakage on imaging. Neither the typical neuroimaging features nor the orthostatic pattern of the headache is included within the diagnostic criteria.2 Classic imaging signs include pachymeningeal enhancement, descent of the brain, subdural fluid collections, enlargement of the pituitary, engorged venous sinuses, and ventricular collapse,3,4 but their presence might vary over time and require the adequate imaging sequences. In the few clinical series that analyze intracranial hypotension,4,5 the orthostatic pattern of the headache is not sensitive but specific. Not every patient with low CSF pressure describes headache, although intracranial hypotension should be considered when patients report worsening after sitting upright or standing and/or improvement after lying horizontally.2,3 Indeed, positional headache is included within the lists of red flags for secondary headaches.6 In our study, we considered headache as suggestive of low CSF pressure when headache appeared after the aforementioned postural changes. We did not include those patients who worsened, to be more specific and avoid the expected worsening by physical activity that might occur in migraine headaches.