NEURORADIOLOGY - IIH

Dr.Roopchand.PSSenior Resident AcademicDepartment of NeurologyTDMC, Alappuzha

INTRODUCTION:

A disorder of unknown etiology. Affects young obese females Presents with features of raised ICT and

papilledema. Otitic hydrocephalus – pre imaging era Pseudotumor ceribri –

pneumatoencephalogram era Benign intracranial hypertension ? Vision Idiopathic intracranial hypertension.

DIAGNOSTIC CRITERIA:

Modified Dandy criteria Signs and symptoms of raised ICT No localizing neurologic signs (exception of a

unilateral or bilateral sixth nerve paresis) CSF may show increased pressure, but no cytologic

or chemical abnormalities. Normal to small symmetric ventricles Diagnostic lumbar puncture done with the patient

in the lateral decubitus position. MRI or MRV should be included to rule out

intracranial venous sinus thrombosis. Other causes of intracranial hypertension should

be ruled out

PATHOPHYSIOLOGY:

Collapsible Dural venous sinuses

Increased arterial blood flow.

Obesity: increased intra abdominal pressure.

ETIOLOGY:

Exposure to or withdrawal of drugs. Systemic diseases Disruption of cerebral venous flow Certain endocrine or metabolic

disorders

CRITERIA FOR INCLUDING A DRUG OR A DISEASE AS A CAUSE OF IIH:

Radhakrishnan et al.. At least 2 cases should have been

described The reported cases should have met all the

criteria for the diagnosis of IIH. Intracranial dural sinus thrombosis should

have been ruled out with reasonable certaintyRadhakrishnan K, Ahlskog JE, Garrity JA, Kurland LT. Idiopathic

intracranial hypertension. Mayo Clin Proc. Feb 1994;69(2):169-80

PNEUMOENCEPHALOGRAM:

CT FINDINGS:

Optic nerve edema due to iihSlit like ventricles

MRI:

pappilloedema, enlarged perioptic csf spaces with mild tortuosity of optic nerves, empty sella , prominent suprasellar cistern

Posterior scleral flattening

Empty sella in IIH

Brain MRI (1.5 Tesla). (a) Sagittal T2-weighted image showing empty sella (white arrow); (b) axial T2-weighted image showing buckling of optic nerves with normal retro-orbital structures; (c) coronal T2-fat saturated image showing increased CSF spaces around bilateral optic nerves; (d) T1 post-contrast coronal image showing empty sella and normal paracavernous structures

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