Pseudotumor Cerebri (Idiopathic Intracranial Hypertension/IIH)

Page Contents

1 WHAT IS IT?
2 WHY IS IT A PROBLEM?
3 WHAT MAKES US SUSPECT IT?
4 HOW DO WE CONFIRM A DIAGNOSIS?
5 HOW DO WE RULE OTHER DIAGNOSES OUT?
6 HOW DO WE TREAT IT?
7 HOW WELL DO THE PATIENTS DO?
8 WAS THERE A WAY TO PREVENT IT?
9 WHAT ELSE ARE WE WORRIED ABOUT?
10 OTHER HY FACTS?
11 ARCHIVE OF STANDARDIZED EXAM QUESTIONS
12 FURTHER READING

WHAT IS IT?

Pseudotumor cerebri (idiopathic intracranial hypertension/IIH) is a condition that is characterized by increased intracranial pressure (ICP) without any clear cause on imaging (i.e. absence of hydrocephalus, obstruction of CSF outflow, and bleeding). The mechanism of this disease is poorly understood, however some believe it is caused by increased CSF production or decreased venous drainage from the brain.

WHY IS IT A PROBLEM?

Increased intracranial pressure (regardless of the cause) can lead to neurological complications such as the impingement of important structures (explained more below for this condition).

WHAT MAKES US SUSPECT IT?

Risk factors:

Obese females of childbearing age, vitamin A excess, danzol usage.

Common Chief Complaints

Headaches are one of the most common complaints
Vision loss that can worse over time
Whooshing buzzing in the ears (pulsatile tinnitus)
Double vision can be the result of cranial nerve VI palsy

History Of Present Illness

Headaches can be associated with nausea and vomiting.

Positional: symptoms are often worse when patient is lying flat in the recumbent position.

Uncommon to have mental status alterations

Physical Exam

HEENT exam:

Decreased visual acuity
Cranial nerve VI palsy

Fundoscopy can reveal the presence of papilledema

Other neurological exam: generally no other focal neurological signs are seen on the physical exam of a patient who only has IIH.

HOW DO WE CONFIRM A DIAGNOSIS?

Lumbar puncture will reveal increased opening pressure (and often also provides headache relief).

CSF pressure above 250 mm H20 can be suspicious for this condition.

CT scan can sometimes reveal small slitlike ventricles and an empty sella sign.

*Psuedotumor cerebri is a diagnosis of exclusion (see next section below for more information)

HOW DO WE RULE OTHER DIAGNOSES OUT?

Imaging of the cranium should not reveal any possible causes of increased ICP (bleeding, tumors, CSF obstruction, hydrocephalus, etc).

Mental status examination typically does not reveal any changes in mental status. If a patient presents with findings on this portion of the exam, other diagnosis should strongly be considered before pseudotumor cerebri

HOW DO WE TREAT IT?

Weight loss is a recommendation for most all patients.

Acetazolamide (first-line): this is a noncompetitive reversible inhibitor of the carbonic anhydrase enzyme and somehow decreases the production of CSF (decreasing intracranial pressure as a result).

Topiramate is an antiepleptic medication

Invasive procedures can be used for more refractory cases. These can include:

Repeat lumbar puncture
CSF shunt placement
Optic nerve fenestration surgery

HOW WELL DO THE PATIENTS DO?

This condition is often self limited, but in roughly half of the cases will have recurrence.

WAS THERE A WAY TO PREVENT IT?

While this condition is idiopathic, patients should abstain from using medications known to increase ICP such as high dose vitamin A derivatives (like isotretinoin for acne), tetracycline, and hormone contraceptives.

WHAT ELSE ARE WE WORRIED ABOUT?

Blindness can result if this condition is not treated.

OTHER HY FACTS?

Chronic vitamin A toxicity is thought to be associated with pseudotumor cerebri

ARCHIVE OF STANDARDIZED EXAM QUESTIONS

This archive compiles standardized exam questions that relate to this topic.