It is now well recognized that idiopathic intracranial hypertension (IIH) can occur in children. Relative to the adult population, the demographic features and clinical presentation of IIH as well as the diagnosis and treatment guidelines for children are quite different. Although these differences are well established, specific diagnostic and treatment guidelines for pediatric patients have largely been based on the adult literature. Exciting new evidence is now available to assist the clinician in managing pediatric patients with IIH.
Key points
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Many children who suffer with headaches first present to their pediatrician for evaluation. Intracranial hypertension must be included in the differential diagnosis. Missing the diagnosis could result in permanent and severe visual loss.
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Idiopathic intracranial hypertension occurs in both children and adults.
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Making the diagnosis of idiopathic intracranial hypertension in a child can now be done with more confidence because of newly outlined diagnostic criteria.
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A significant percentage of pediatric patients with intracranial hypertension will have an identifiable secondary cause.
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Most children diagnosed with idiopathic intracranial hypertension will respond well to medical management alone.
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Surgical intervention is reserved for those who fail to respond medically.
Introduction
Idiopathic intracranial hypertension (IIH) is defined as elevated intracranial pressure (ICP) without clinical, radiologic, or laboratory evidence of a secondary cause. The most frequently cited incidence data for IIH in the general population of the United States are from a study by Durcan and colleagues, who reported the incidence to be 1 in 100,000 individuals. When restricting the inclusion criteria to women aged 20 to 44 years, who are 20% or more above their ideal body weight, the annual incidence increases to 15 to 19 cases per 100,000 in the United States. Although it has historically been described as a condition affecting obese women of childbearing age, it can occur in all age groups and genders in both obese and nonobese individuals and is becoming more recognized in the pediatric population.
Introduction
Idiopathic intracranial hypertension (IIH) is defined as elevated intracranial pressure (ICP) without clinical, radiologic, or laboratory evidence of a secondary cause. The most frequently cited incidence data for IIH in the general population of the United States are from a study by Durcan and colleagues, who reported the incidence to be 1 in 100,000 individuals. When restricting the inclusion criteria to women aged 20 to 44 years, who are 20% or more above their ideal body weight, the annual incidence increases to 15 to 19 cases per 100,000 in the United States. Although it has historically been described as a condition affecting obese women of childbearing age, it can occur in all age groups and genders in both obese and nonobese individuals and is becoming more recognized in the pediatric population.
Nomenclature
There has been much discussion and debate about the appropriate nomenclature to describe this condition. Historically, the condition has been referred to by terms such as meningitis serosa, otitic hydrocephalus, hypertensive meningeal hydrops, pseudotumor cerebri, benign intracranial hypertension, idiopathic intracranial hypertension, and, most recently, pseudotumor cerebri syndrome. With so many names, confusion and misunderstanding can occur. The more descriptive term “intracranial hypertension,” which is then further classified as either “idiopathic” or “secondary,” is used in this discussion. The term “idiopathic” is reserved for those cases in which known secondary causes have been excluded. The term “secondary” is used for those cases in which an underlying cause is identified. These terms are simple, descriptive, and understood by all clinicians. It is important to recognize that little is known about the pathophysiology of IIH. It is quite possible that what is referred to today as “idiopathic” may likely become “secondary” as more is learned about the disease process.
Demographics
More information is becoming available regarding the demographics of pediatric IIH. Current data suggest that prepubertal children affected with intracranial hypertension are more likely to be secondary rather than idiopathic in nature. In addition, the association with obesity and female gender does not hold true in this population. Studies also suggest that IIH is infrequent in children less than 10 years of age and extremely rare in infants less than 3 years old.
Associated conditions
There are a myriad of secondary causes of intracranial hypertension and knowledge of these associated conditions will aid the clinician during the history and examination of the patient and can assist in guiding the subsequent workup. It is worth mentioning again that pediatric intracranial hypertension is more likely to be secondary in nature than idiopathic. Systemic conditions, cerebral venous abnormalities, drugs, endocrine abnormalities, and infectious causes have been identified as secondary causes of intracranial hypertension in the literature ( Box 1 ). The exact mechanism by which these conditions result in secondary intracranial hypertension is not entirely understood in all cases.
| Medical and Systemic Conditions | Infectious Diseases | Drugs |
|---|---|---|
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Clinical presentation
The clinical presentation of pediatric IIH includes many of the same symptoms and objective findings as the adult patient. Headache is by far the most common symptom of IIH and occurs in more than 90% of cases. There is no specific headache pattern that is pathognomonic of IIH; therefore, a thorough history and physical examination are needed to try and determine the need for further evaluation. Other symptoms include neck, shoulder, or arm pain, nausea, vomiting, pulsatile tinnitus, diplopia, blurred vision, and transient obscurations of vision. Diplopia can be secondary to unilateral or bilateral sixth nerve palsies. The sixth cranial nerve is susceptible to damage from high ICP alone. Infrequently, patients may present with no suggestive symptoms at all and are only diagnosed when papilledema identified on routine eye examination prompts a further workup. For example, a thin 14-year-old girl presented for her regular eye examination and was found to have papilledema. She had been started on clindamycin for acne 8 weeks previously. Only retrospectively when prodded did she complain of new headaches. Within 2 weeks of stopping the clindamycin, all signs and symptoms resolved. Many children with refractive errors have experienced headaches when their glasses need updated, and it is possible for children to attribute blurry vision and headaches to the need for new glasses. This type of headache should be intermittent and mild.
Evaluation
A thorough history is imperative when assessing a child with IIH. Both the parent and the child should be involved when the history is obtained, because the child’s input can be a source of valuable information. The history should be focused on clarifying the patient’s symptoms and identifying potential secondary causes. Demographic information should include the child’s age, gender, and weight. Specific questioning should address stage of puberty, recent illnesses, medication use, recent weight gain, headache, nausea, vomiting, neck and back pain, systemic illnesses, and other neurologic complaints.
The clinical examination should focus on identifying features of IIH. Neurologic and ophthalmologic assessments are indicated. The ophthalmologic evaluation in the pediatrician’s office should include a vision test, extraocular motility evaluation (specifically looking for abduction deficits that might indicate the presence of sixth nerve involvement), pupil evaluation, and examination of the optic nerve with a direct ophthalmoscope. The presence of disc edema in an undilated pupil can be very difficult to evaluate especially if it is very mild ( Fig. 1 ). Moderate papilledema ( Fig. 2 ) and florid papilledema ( Fig. 3 ) are more obvious and can be accompanied by retinal hemorrhages and cotton wool spots. Pseudopapilledema can be caused by the presence of drusen buried in the nerve head ( Fig. 4 ). Even if the nerves look normal ( Fig. 5 ), this should not preclude referral to a pediatric ophthalmologist because the appearance might be evolving or disc edema could be absent. Evaluating the nerves and seeing any evidence of disc edema help the pediatrician make the referral emergent. The neurologic examination should be directed at identifying any focal neurologic deficits. If referral is warranted, the ophthalmic examination should be performed by an ophthalmologist familiar with the condition. The detailed examination should include assessing visual acuity, color vision, visual fields, extraocular movements, and a careful anatomic evaluation. Papilledema is the most important clinical finding because it is associated with vision loss, the most feared consequence of IIH. Photographs of the optic nerve are taken for monitoring purposes. The role of optical coherence tomography (OCT) in identifying and monitoring papilledema is not yet clear. The author currently performs this test on every patient and has found it to be a useful tool for monitoring response to treatment. OCT is a noninvasive imaging test that uses light to measure different layers in the retina and optic nerve. OCT is proven to be helpful in other ocular diseases, including glaucoma, diabetic retinopathy, and macular degeneration. If studies confirm that OCT is accurate and reliable in evaluating the response to treatment in patients with IIH, it will help decrease the number of lumbar punctures (LPs) performed on children with IIH.
