Idiopathic Intracranial Hypertension

At a glance

Idiopathic Syndrome caused by increased intra­cranial pressure with papilledema of unknown origin, most often presenting with symptoms of cerebral tumor (pseudotumor cerebri) in young obese women in their childbearing years. It is a neuro­logical disorder that is characterized by increased intracranial pressure in the absence of a tumor, increased cerebrospinal fluid, or other intracerebral conditions. Clinically, it is characterized by headache (pathognomonic) that occurs in 92 to 94% of cases. The symptoms are worse in the morning and throbbing in nature.

Synonyms

Benign Intracranial Hypertension; Pseudotumor Cerebri.

Nature

This is a clinical syndrome characterized by increased intracranial pressure of unknown origin with good prognosis if medical treatment (eg, acetazolamide, furosemide) is taken regularly. Severe cases are often associated with visual impairment and may require neurosurgical interventions. A lumbar puncture can resolve, temporarily and sometimes permanently, this medical condition.

Incidence

This medical condition can be seen at any ages. It is more frequent in women than men. The incidence in the United States has been reported to range from 0.9 to 1.0:100,000 in the general population. However, this rate is estimated to be 1.6 to 3.5:100,000 in women and 7.9 to 19:100,000 in overweight women. Internationally, the incidence varies considerably among countries. However, the relationship between personal habitus such as obesity has been confirmed. In Libya, it has been demonstrated that the incidence was estimated at 2.2:100,000 in the general population, 4.3:100,000 in women, and 21.4:100,000 in obese women.

Pathophysiology

Idiopathic intracranial hypertension is a clinical syndrome characterized by an elevated intracranial pressure with normal cerebrospinal fluid (CSF) composition and no evidence of any expanding intracranial mass lesion or significant hydrocephalus. In all cases, increased vitamin A concentration is measured in the CSF of affected women. Females are more affected than males. Most often, no specific cause is found; however, multiple causes have been identified: endocrine and metabolic disorders (hypoparathyroidism, pseudohypoparathyroidism, corticosteroid therapy withdrawal, growth hormone treatment, hypervitaminosis A, Addison disease, obesity, menarche, oral contraceptives, pregnancy, galactosemia), hematologic disorders (iron deficiency and hemolytic anemia, polycythemia, Wiskott-Aldrich Syndrome), infections (roseola infantum, chronic otitis media and mastoiditis, Guillain-Barré Syndrome), drugs (tetracyclines, nalidixic acid), and obstruction of intracranial drainage by venous thrombosis (head injury, lateral or posterior sagittal sinus thrombosis, obstruction of superior vena cava).

Diagnosis

Clinical course; CT scan or MRI excluding any structural cause for increased intracranial pressure and showing normal ventricles; lumbar puncture revealing elevated CSF opening pressure and normal CSF composition (chemistry, cytology, bacteriology). Lumbar puncture is therapeutic, allowing CSF to escape, thereby reducing the intracranial pressure. Digital subtraction angiography may be performed if there is suspicion of venous thrombosis.

Clinical aspects

Some patients are asymptomatic. Infants may present with irritability, ...