Pseudotumor Cerebri (Idiopathic Intracranial Hypertension)

Description

• Increased intracranial pressure with no clear pathophysiology
• Many have suggested calling it pseudotumor cerebri syndrome emphasizing the variety of subtypes (1).
• Subtypes include true idiopathic intracranial hypertension, idiopathic intracranial hypertension with underlying cause, and idiopathic intracranial hypertension without papilledema.

Epidemiology

Incidence

• 0.9/100,000 in general population (2)
• 4 to 11.9/100,000 in obese women
• 19/100,000 in women >20% over ideal body weight and reported 323/100,000 in those seeking bariatric surgery (3)
• Lower incidence in Scandinavia in adults of 0.65/100,000 (4)
• In children age <7 years, males and females equally affected
• Children age >7 years, obese girls have doubled incidence of obese boys and more than doubled for age 12 to 15 years (5).
• Rare in children <3 years or adults >60 years
• Men potential bimodal distribution, prepubertal and middle-aged (6)
• Hypothesized increasing incidence due to increased rates of obesity but not studied

Prevalence

• Prospective studies show 90–98% are women (7). Others show 9% prevalence in males considering all age groups (8).
• 2–12% of pregnant females (9)
• Female to male ratio ranges in adults from 4:1 to 6.1:1 (4)

Etiology and Pathophysiology

• Unknown certain etiology
• Associated with obesity; fewer cases in countries with less obesity (4)
• Questionable association with increased intra-abdominal pressure (10)
• May be associated with increased vitamin A levels and corticosteroid treatment (10)
• Possible new cause with elevated aldosterone
• Related to sex hormones; noted to be associated with polycystic ovarian syndrome and low testosterone in men (8); theorized related to female hormones because significant difference in incidence in females regardless of obesity during reproductive years
• Questions concerning whether venous sinus stenosis is the cause of or the consequence of idiopathic intracranial hypertension (10)

Genetics
No known hereditary factors

Risk Factors

• Rapidly increasing weight gain (2)
• Prepubertal children do not have associations with obesity (3,5).
• Female sex during reproductive years

General Prevention

Because correlated with weight gain, weight management is the only known prevention, with potential support in studies of children (5).

Commonly Associated Conditions

• Polycystic ovarian syndrome often comorbid; uncertain if sex hormones have causal relationship or both diagnoses exist in overweight and obese women of reproductive age (10)
• Obstructive sleep apnea more common in men with pseudotumor cerebri (24% vs. 4% of women) (8)
• Other potential links are with tetracycline use (more in adolescents for acne) (10).