Learning objectives
Intracranial pressure (ICP) can be estimated by measurement of the cerebrospinal fluid (CSF) opening pressure at lumbar puncture.
In the steady state,
pressure within the brain parenchyma and intracranial extra-axial spaces are equal.
ICP increases with Valsalva maneuver,
and falls bellow atmospheric pressure in the standing position.
The Monro-Kellie doctrine describes the relationship among volumes and pressures in the intracranial space.
Is is based on the principle that,
within the fixed volume of the intracranial and intraspinal spaces,
the total volume of CSF,
brain and...
Background
IDIOPATHIC INTRACRANIAL HYPERTENSION
Idiopathic intracranial hypertension (IIH) is characterized by raised ICP of unknown cause.
It is rare but important disease associated with significant morbidity,
including permanent vissual loss in up to 25% of cases.
Incidence of IIH is steadily increasing (1-2 per 100.000 population).
Females are more affected than males (tipically affecting young women of childbearing age).
Children as young as 4 months can be affected with equal sex distribution.
IIH has been associated with conditions related to increased intra-abdominal,
visceral fat and elevated...
Findings and procedure details
IMAGING FEATURES IN IDIOPATHIC INTRACRANIAL HYPERTENSION
Neuroimaging in IIH has traditionally performed to exclude other causes of elevated ICP,
such as space-occupying mass lesion and venous sinus thrombosis.
However,
it has become clear that a variety of imaging findings involving the orbit,
skull base,
brain and transverse sinuses are commonly found in patients with IIH.
Hence,
latest diagnostic scheme for IIH incorporates imaging findings as criteria for a diagnosis of "possible IIH" when papilledema is absent.
Optic nerve abnormalities
Optic nerve head protrusion in severe...
Conclusion
IIH and ISH are rare disorders that may lead to irreversible disabilities,
therefore requiring rapid and accurate diagnosis.
IIH remains a diagnosis of exclusion,
and imaging findings should not prompt invasive procedures,
unless other signs of IIH (such as papilledema) are present.
MRI depicts imaging markers of SIH in patients presenting with headache and neck pain.
Personal information
Amaya Hilario
Department of Radiology,
Universitary Hospital 12 de Octubre,
Madrid,
Spain
References
1.
Portelli M,
Papageorgious PN.
An update on idiopathic intracranial hypertension.
Acta Neurochir 2017;159:491-99
2.
Holbrook J,
Saindane AM.
Imaging of intracranial Pressure Disorders.
Neurosurgery 2017;80:341-354
3.
Urbach H.
Intracranial hypotension: clinical presentation,
imaging findings,
and imaging-guided therapy.
Curr Opin Neurol 2014;27:414-424