Pediatric pseudotumor cerebri

Pseudotumor cerebri (PTC) is a condition of increased intracranial pressure with normal cerebral spinal fluid (CSF) composition and no underlying structural abnormalities. PTC can be secondary to an underlying etiology (e.g., medication, anemia,venous sinus thrombosis) or can be primary. Primary PTC is also referred to as Idiopathic Intracranial Hypertension (IIH). PTC is diagnosed using modified Dandy criteria.

Modified Dandy Criteria

1) increased intracranial pressure (lumbar puncture) with opening pressure (>20 cm H2O) 2) clinical signs attributable only to increased intracranial pressure 3) normal CSF composition 4) normal neuroimaging (e.g., no mass lesion, hydrocephalus, other structural lesion,etc.)

Epidemiology

PTC is more commonly seen in young obese women of childbearing age, with a prevalence of (19.3/100,000). The same study shows a prevalence of (0.9/100,000) in the general population. In a Canadian study the prevalence of PTC in the pediatric population was found to be (1/100,000) with equal incidence between boys and girls. Therefore, although PTC is more common in women of childbearing age, PTC is still observed in the pediatric population as well. PTC in childhood requires exclusion of different etiologies that might raise the intracranial pressure.

Pediatric PTC vs Adult PTC?

Secondary PTC is more common than primary PTC (i.e., pediatric IIH) in children compared with adults. This is helpful in terms of putting more emphasis on finding the underlying cause of PTC in the pediatric population. The typical risk factors and presentation of PTC do not apply to pediatric patients. For example, obesity is one of the major risk factors in adult PTC, but it does not seem to have the same effect in the pediatric population. In a study done at University of Iowa, it was found that only 32% of pediatric patients with PTC were obese (approximating the natural rate in this population), whereas in other studies more than 80% of adults with PTC were obese. Overweight women of childbearing age is the typical presentation of PTC patients. However, in the pediatric population the incidence between male and female is equal. Therefore when a child walks into the doctor's office and is diagnosed with PTC, the physician should be more concerned with secondary causes of PTC.

The course of secondary PTC in children is better than the course of pediatric IIH; and children with PTC or pediatric IIH are less likely to require surgical intervention compared with adult IIH.( This is concluded from a recent study at Iowa which is being submitted for publication)

Common secondary causes of PTC in pediatric population

-Venous sinus thrombosis: Venous sinus obstruction leads to increased venous pressure and elevated CSF pressure. -Trauma -Ear infection -Tetracycline and its analogues (minocycline,…etc):

Adolescents who take tetracycline for their acne may present in clinic with signs of increased intracranial pressure. The mechanism is not well understood but this class of antibiotics compose a large number of patients with PTC. Tetracycline manifestations of PTC is independent of age, gender and obesity. It is not clear as to how much exposure and what duration is needed to trigger PTC. However in one of the largest studies of PTC patients who were exposed to Minocycline; there was a huge range between 2 weeks up to 1 year of minocycline use before patients became symptomatic. -Renal Failure:

Renal failure was reported by Dogulu et al. In their study eight patients with renal failure were found to have PTC. -Vitamin A -Leukemia -Lupus Recent studies on PTC have characterized the common etiologies that would lead to PTC in childhood. Four different studies including a study of 68 pediatric patients by baker et al confirmed ear infection as one of the most common etiologies of PTC in children. However, in another study done by Couch et al among 38 children with pseudotumor cerebri only 3 cases were due to ear infection or its complications. Furthermore, in other studies, PTC has been associated with obesity, recent weight gain, female gender, and steroid withdrawal. Tetracycline use, Vitamin A derivatives, systemic diseases, and venous thrombosis have also been reported as common causes of secondary PTC.

Sign and symptoms of PTC:

-Headache: this is the most common sign of PTC -Blurred vision -Transient visual obscurations: loss of vision for a short period of time (lasting 3-5 seconds)in one or both eyes usually associated with papilledema. This usually happens with postural changes (example: when going from sitting to standing position) and the patient describes a momentary blackening of vision. -Papilledema

There could be patients with PTC who do not have any papilledema, or who have unilateral or asymmetrical papilledema. -Sixth nerve palsy: usually leads to diplopia -Loss of visual acuity or a visual field defect -Pulse Synchronous Tinnitus: Wooshing noise in the ear

Prognosis

It is well known that adult PTC is associated with substantial visual loss. However visual loss as a result of PTC has been reported in many case series of pediatric population as well. In a study done by Lessel et al five children and adolescents suffered permanent visual loss. In another larger study done by Baker et al, out of 36 pediatric patients with PTC, four had rapid and severe loss of visual acuity and six others less severe abnormalities of visual acuity.

Treatment

The ultimate goal of PTC treatment is to lower the intracranial pressure and optic disc edema. There are several therapies including medications and surgical treatments which are mentioned in the pseudotumor cerebri article in Wikipedia. The most common medication is Diamox. Another treatment is with Topiramate (Topomax). Topomax has been shown to be an effective headache medication. Both Diamox and Topamax are a carbonic anhydrase inhibitors (this can lead to less production of CSF, which can lower the intracranial pressure) with weight loss as one of its desirable side effects. Since pediatric PTC has more association with secondary causes, it is of great importance to investigate the underlying etiology and treat those accordingly. For example, discontinuation of tetracycline, Vitamin A and steroids would be the first line of treatment for those patients who consume these drugs. For those patients with dural sinus thrombosis standard treatment involves heparin or warfarin anticoagulation therapy or direct endovascular thrombolytic therapy.

References

-Friedman DI, Jacobson DM. "Diagnostic criteria for idiopathic intracranial hypertension". Neurology 2002;59:1492–1495.

-Durcan FJ, Corbett JJ, Wall M. "The incidence of pseudotumor cerebri. Population studies in Iowa and Louisiana". Arch Neurol 1988;45:875-7.

-Baker RS, Carter D, Hendrick EB, Buncic JR: "Visual loss in pseudotumor cerebri of childhood: A follow-up study". Arch Ophthalmol 103:1681–1686, 1985.

-Ingrid U. Scott; R. Michael Siatkowski; Mazen Eneyni; Michael C. Brodsky; Byron L. Lam "Idiopathic intracranial hypertension in children and adolescents". American Journal of Ophthalmology, August 1997 v124 n2 p253(3).

-Corbett JJ, Thompson HS: The rational management of idiopathic intracranialhypertension. Arch Neurol 46:1049–1051, 1989.

-Couch R, Camfield PR, Tibbles JA. "The changing picture of pseudotumor cerebri in children". Can J Neurol Sci, 1985 Feb;12(1):48-50.

External links

* [http://www.experienceproject.com/group_profile.php?g=7347 Patient Experiences with Pseudotumor Cerebri]