Signs of IH
Chronic IH is often characterized by an absence of clues. In idiopathic intracranial hypertension (IIH), there is no brain tumor, hemorrhage, cyst, lesion or blood clot found on a brain scan, no abnormalities of CSF and no localizing findings that point to injury of specific brain areas. In some cases of secondary intracranial hypertension (SIH), diagnosis may come long after the initial injury or trigger has occurred, leaving elevated intracranial pressure as the only evidence. Plus, a diagnosis of either IIH or SIH may be further complicated by the fact that a person does not exhibit all of the telltale symptoms.
However, there are some additional physical signs a physician may encounter that point to chronic IH. (A sign refers to something a physician can see, while a symptom is something a patient feels.)
Papilledema: Swelling of the optic nerves is probably the most common sign of IH. One sign of papilledema is an increased optic nerve diameter. An afferent pupil defect, in which the pupil in the eye is slow to react to light, can also indicate optic nerve swelling. Sixth nerve palsy due to elevated intracranial pressure may account for double vision and the eyes not tracking well together.
Visual field abnormality: Visual field abnormalities including peripheral and inferior nasal vision loss detected on a visual field test can be signs of chronic IH.
Empty sella: The pituitary gland, which is responsible for the body’s hormonal function, resides inside the sella turcica (cell-lah tur-sick-ah), a saddle-shaped space surrounded by the skull. Normally, the relatively round pituitary gland is visible within the sella turcica on imaging studies such as MRIs, CT scans and skull X-rays. Chronic IH can cause the pituitary gland to flatten against the skull bone, which gives the appearance that the sella turcica is empty.
Posterior scleral flattening: The sclera (the outer white covering of the eye) at the back of the eye can appear flattened on a CT or MRI scan, as a result of chronic IH.
The arrow points to an empty sella turcica.
An example of posterior scleral flattening (both eyes).