Teaching Case

Attacks of postural headaches associated with nausea and vomiting, getting worse in the standing position.

The patient presented with attacks of postural headaches, associated with some degree of nausea and vomiting. Symptoms were exacerbated in standing (upright) position. Each attack lasted for 7-10 days with spontaneous recovery following bed rest. The frequency of the attacks varied between 2 to 4 per year. The previous medical history of the patient is completely unremarkable other than these attacks, which affected the patient for about 10-11 years. Magnetic resonance imaging (MRI) examination of the patient was performed on a 1.5 T MR scanner. T1 and T2 weighted images as well as post-gadolinium T1 weighted images were obtained.

Spontaneous intracranial hypotension is a rare benign and usually self-limited phenomenon of unknown etiology, which is characterized by postural headache, neck rigidity, nausea and vomiting. The clinical findings are related to the low intracranial pressure, which can be classified as spontaneous or primary and secondary types (e.g. following lumbar puncture, due to rupture of a root sleeve cyst ). The imaging findings of spontaneous intracranial hypotension on cranial MRI are characteristic with diffuse intracranial pachymeningeal thickening and enhancement following intravenous gadolinium, not only at the cranial level, but also at the level of cervical spinal dura in some cases. The most pathognomonic finding, diffuse pachymeningeal thickening and contrast enhancement, is thought to be due to an increase in dural blood volume resulting from the low intracranial pressure. The brainstem and cerebellar tonsils displace downwards, reflecting the low pressure within the spinal subarachnoid space. The ventral margin of the pons seems flatter than normal, the fourth ventricle looks narrowed. The cerebral hemispheres also show caudal displacement with the same mechanism. All the above findings are reversible when the cause of low pressure is corrected. Unusually prominent enhancement of the choroid plexus, enlarged dural veins, subdural effusions can be observed as additional MRI findings.