Spontaneous intracranial hypo and hypertensions: an imaging review

Cerebrospinal fluid (CSF) pressure changes can manifest as either intracranial hypertension or hypotension. The idiopathic forms are largely under or misdiagnosed. Spontaneous intracranial hypotension occurs due to reduced CSF pressure usually as a result of a spontaneous dural tear. Idiopathic intracranial hypertension (IIH) is a syndrome of elevated intracranial tension without hydrocephalus or mass lesions and with normal CSF composition. Neuroimaging plays an important role in excluding secondary causes of raised intracranial tension. As the clinical presentation is varied, imaging may also help the clinician in arriving at the diagnosis of IIH with the help of a few specific signs. In this review, we attempt to compile the salient magnetic resonance imaging findings in these two conditions. Careful observation of these findings may help in early accurate diagnosis and to provide appropriate early treatment.