Idiopathic intracranial hypertension (IIH) is a disorder characterized by elevated intracranial pressure (ICP) of unknown origin. This condition can manifest through a range of debilitating symptoms, including increased intracranial pressure (ICP), tinnitus, headaches, a potential risk for permanent vision loss, and poor quality of life. Although it can affect any age and gender, it is classically seen in obese or overweight women of childbearing age. Notably, most patients living with IIH also have obesity. The rising incidence of IIH likely reflects the continuing upward trend in obesity worldwide.
Understanding Idiopathic Intracranial Hypertension (IIH)
As per the modified Dandy criteria, IIH is defined by signs and symptoms suggestive of elevated ICP, including severe headaches and vision loss, in the absence of neurologic deficits (although cranial nerve VI palsies may occur) and with elevated ICP in the context of normal neuroimaging and cerebrospinal fluid analyses. Although uncommon overall, the incidence of IIH is on the rise. As of this writing, the overall incidence of IIH is approximately 2 per 100,000, which is an increase from approximately 1 per 100,000 in 1988.
The Obesity Connection
Although other known risk factors and systemic disease associations exist, weight remains the primary risk factor for IIH. The rates of obesity among patients with IIH have been examined in several studies worldwide. A retrospective study from Detroit Medical Center determined that more than 90% of IIH patients are obese. Similar literature exists worldwide, with another study from Israel reporting that 97.2% of IIH patients were obese. A study done in the UK demonstrated that the incidence of IIH in obese women was 11.9 per 100,000. In another study of obese US women being evaluated for bariatric surgery, the incidence has been reported to be as high as 323 per 100,000. In contrast to absolute weight alone, IIH is also associated with recent weight gain, as seen in a study of newly-diagnosed IIH patients, which found an increased risk of IIH among those who had gained 5-15% of body weight in the 12 months prior to diagnosis. Some evidence has suggested that IIH is a distinct metabolic disease rather than belonging on the neuro-ophthalmic axis, as IIH has a pathophysiology which hinders weight loss and promotes weight gain.
The risk of IIH increases as a function of body mass index (BMI) and weight gain over the preceding year. The risk of IIH-induced vision loss also increases with increasing BMI, especially with BMI >40 kg/m. Several mechanisms have been proposed linking obesity to the development of IIH but the pathophysiology remains unknown.
The Role of Weight Loss in Managing IIH
Establishing the role of weight loss in IIH began with the work by Newborg in 1974. This research showed that a low salt, fluid restricted diet consisting solely of rice could result in rapid weight loss and alleviation of all IIH symptoms; all 9 patients in this study showed improvement with this intervention. Unfortunately, the most important outcome measure for IIH trials, visual field function, was not measured. A growing body of literature supports the ubiquitous role of weight loss in the treatment of IIH.
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Published studies and clinical observations strongly support weight loss as an effective treatment, although there are no prospective controlled trials. Weight loss in the range of 6%-10% often leads to IIH remission.
Impact of Weight Loss on Papilledema
A retrospective study conducted by Johnson et al in 1998 demonstrated that a 6.2% weight loss in IIH patients is associated with resolution of papilledema (three-grade change in the Frisen scale). This study also demonstrated that the degree of weight loss was correlated with the amount of papilledema resolution, with a 3.3% weight loss corresponding to only a one-grade change in papilledema. Results similar to the work by Johnson have been reproduced, including a similar report by Kupersmith et al, which found that IIH patients with a weight loss of 2.5 kg during a 3-month period experienced more rapid improvements in papilledema and visual field testing when compared with those who did not lose weight. This study further supports the notion that the rate of weight loss is also an important factor in the treatment of IIH.
Lifestyle Interventions: A Low-Energy Diet Approach
A prospective study by Sinclair et al analyzed weight loss by placing women with IIH on a low energy diet. The intervention was divided into 3 stages, each lasting 3 months: no intervention, low calorie diet (425 kcal/day), and a follow-up period. The results showed that subjects who complied with the low energy diet for 3 months experienced weight loss, improvement of visual function, headaches, papilledema, ICP, and also experienced a reduction in analgesic use; these changes were also observed after cessation of the diet in the follow-up period. For lifestyle interventions, the most supported strategy was the very low energy diet (VLED) intervention, in which patients lost an average of 15.7 kg at 3 months. Short-term dietary interventions associated with modest reductions in weight at 3 to 6 months, but weight loss was not significant at a follow-up of 10 to 11 months.
The Idiopathic Intracranial Hypertension Treatment Trial (IIHTT)
Perhaps most compelling, however, are the results of the Idiopathic Intracranial Hypertension Treatment Trial (IIHTT), a randomized, controlled trial examining the effects of acetazolamide on visual field function in IIH patients with mild visual loss. Compared to controls, the acetazolamide group experienced significant increases in weight loss (6% versus 3%) as well as improvements in visual field function, CSF pressure, papilledema grade, and quality of life measures in IIH.
Surgical Interventions: Bariatric Surgery and IIH
Similar to the outcomes seen from weight loss by lifestyle modifications, weight loss via bariatric surgery offers complementary benefits for certain subsets of patients. A study by Sugerman found that bariatric surgery had a higher success rate in resolving IIH symptoms compared to CSF peritoneal shunting in severely obese patients (pre-operative BMI average of 47), with symptom resolution in all but one patient within 4 months of surgery. This surgery also offers the benefit of resolving a number of comorbidities associated with obesity, including hypertension, diabetes, degenerative joint disease, sleep apnea, and gastroesophageal reflux disease.
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Systematic Review of Bariatric Surgery Outcomes
A systematic review of 17 publications discussing bariatric surgery in IIH patients demonstrated an improvement in headache symptoms (92% of patients), visual field improvements (93% of patients), resolution of pulsatile tinnitus (88% of patients), and resolution of papilledema (100% of patients). Out of the 17 studies, 8 (122 participants) reported on bariatric surgery interventions, including gastric band, sleeve gastrectomy, and gastric bypass. In studies that reported on outcomes from gastric band, gastric bypass, or sleeve gastrectomy interventions, the average weight loss was 27.2 to 27.8 kg at 24 months. Compared with gastric band, gastric bypass was associated with significantly greater weight loss at 24 months (P <.001) and between 91 and 108 months (P =.007).
Bariatric Surgery vs. Non-surgical Weight Loss
Bariatric surgery achieved 100% papilloedema resolution and a reduction in headache symptoms in 90.2%. Non-surgical methods offered improvement in papilloedema in 66.7%, visual field defects in 75.4% and headache symptoms in 23.2%. Surgical BMI decrease was 17.5 vs. non-surgical decrease of 4.
Weight Regain and IIH Recurrence
According to a case-control study by Ko et al, 26/50 patients had a higher BMI at the time of symptom recurrence than at initial diagnosis (+2.0 BMI) when compared to patients without recurrence (-0.75 BMI). Interestingly in this study, the average BMI of patients without recurrence was higher than those with recurrence at all points of observation during the study. The average percentage change in body weight between patients with and without recurrence was 6% and 0%, respectively, between initial resolution and recurrence. Weight is typically regained over 1-3 years but about a third of patients maintain â¥5% weight loss over the long term. Patients treated initially with lifestyle modification therapy show a modest persisting benefit over self-directed patients. Selected commercial weight loss programs also may improve long-term maintenance of weight loss.
Counseling and Personalized Weight Management
There is a surprisingly sparse amount of data regarding who is most effective at counseling patients about weight loss; specifically, no body of evidence exists that directly compares patient weight loss outcomes between physicians and non-physician providers. However, there is no shortage of literature which consistently demonstrates that obese and overweight patients who receive advice from physicians have a statistically significant effect on weight loss versus those who do not. This significant effect is mediated by both patient engagement in weight loss efforts as well as with absolute weight reduction. As a result of the consistent results on this subject, numerous guidelines recommend that physicians and primary care providers should counsel their overweight and obese patients on weight loss. Moreover, a great deal of research has examined the effect of multidisciplinary teams in weight loss.
With regard to specific weight loss strategies, personalized weight-management plans are pivotal. Using "patient-centered language" and shared decision making may be the most effective way that physicians can engage with patients in long-term weight loss solutions. Patient-centered language involves using non-judgmental language to describe weight and weight gain and focusing on the overall health impact that results rather than the physical appearance of weight gain. Shared decision making allows patients to dictate the goals of care and weight loss interventions.
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Motivational Interviewing
One specific example of a patient-centered communication weight loss strategy is motivational interviewing, which entails four steps: engaging the patient in a non-medical conversation about weight loss, focusing on a specific change, eliciting a reason to change from the patient, and planning the actual intervention to change. In this strategy, a patient-centered conversation somewhat removed from medicine guides the conversation with the goal being to engage the patient in such a manner that they outline their own weight loss plan.
Comprehensive Assessment and Planning
When assembling a personalized weight-loss plan for a patient, it is important to consider their current medication regimen and assess for any medications that are associated with weight gain and whether or not they can be substituted by a medication that will not affect their weight, or, which may even facilitate weight loss.
Behavioral Interventions for Weight Loss
The major goal of behavioral intervention is to modify diet and lifestyle in order to create a negative energy balance. Three recommended dietary approaches to achieve a negative energy balance include a general caloric restriction (1,200-1,500 kcal/day for women 1,500-1,800 kcal/day for men), prescribing a 500-750 kcal/day energy deficit, and restricting certain types of foods (high carbohydrate, high fat, low fiber). Physical activity recommendations aim for moderate-to-vigorous activity for >150 minutes per week, preferably 30 minutes daily. Used in combination, these two strategies are highly effective weight loss tools.
According to the 2013 Guidelines, it is recommended that patients follow-up in person with a trained obesity-specialist at least twice monthly. However, it is important to note that the effectiveness of these behavioral interventions is often not transferrable from the specialist setting to that of primary care. One promising behavioral intervention that can be utilized in the primary care setting is the 5 A's model. This model is derived from the National Cancer Institute's model for smoking cessation. Although several iterations exist, the version endorsed by the USPSTF consists of the following 5 A's: Assess, Advise, Agree, Assist, and Arrange. With regard to the specific components, patients particularly like physicians to help "Assist" and "Arrange" (provide adjunctive support, referrals to dieticians/specialists, etc.). Other components generate more controversy, especially in regard to those that require physician's to identify that a patient has a weight issue, and thus can be perceived by patients as passing judgment. At present, the utility of the model is highly variable as is the data that supports it.
Technology-Based Solutions
The use of technology-based behavioral weight loss solutions has also been shown to be effective. Interventions in this category generally have 5 key technical components: self-monitoring, counselor feedback and communication, group support, and use of a structured and individually-tailored program. Interventions that used a combination of at least 4 of these components led to significant decreases in weight compared to controls. Features such as these actually contribute to fairly high adherence rates to treatment plans. However, it is important to note that many technology-based weight loss options exist, and data regarding which specific solutions are optimal is still inconclusive. In a pilot study by Choo et al, a specific technology-based solution involving use of a mobile app and linked accelerometer for a clinic-based weight loss program was evaluated. While the researchers in this study found that their technology-based intervention could be a useful tool for weight management from the standpoint of usability and adoption, it was found to negatively impact the doctor-patient relationship.
Patient Education and Smart Eating
Lastly, due to the poor long-term outcomes of dieting (i.e., weight management resulting in dealing with significant periods of hunger during the day), patient education is very important. This includes counseling patients to eat only when hungry, to stop eating when full, and on "eating smart" (i.e., choosing non-processed foods with a high percentage of foods of high volume and low caloric value, such as fresh foods and vegetables). Meals should contain items that provide a feeling of satiety so that one is not hungry after several hours, and not necessarily chosen for low caloric value. Traditional dieting also involves limiting consumption to small portions or special kinds of food in order to lose weight and may lead to a feeling of hunger for substantial periods during the day.
The optimal weight for a person is not only measured by pounds or BMI. A healthy weight may very well be better defined in terms of fitness (adequate exercise), % body fat and healthy eating habits. Our Neuro-ophthalmology division at the University of Iowa has devised principles that lead to a healthy weight.
- Thou shalt limit calories in a reasonable way. But, it is equally important to compose a meal that will satiate your appetite for more than a few hours.
- Thou shalt not habitually eat foods with "empty calories." These are caloric foods that do not fill you up.
- Thou shalt keep moving (exercise regularly). Avoid sitting regularly for long periods (sitting disease).
One should think "make good choices" and not "diet." Instead of starving oneself for periods of time, choose foods that allow you to fill up on fewer calories. These are foods that are unprocessed, high in fiber, and low in fat and sugar. Examples include: fruits, vegetables, cooked whole grains such as barley, oatmeal, whole-wheat products and brown rice, and legumes.
Pharmacologic Weight Loss Treatments
Pharmacologic weight loss treatments are intended to be used by patients on low-calorie diets and increased exercise regimens. In order to be considered eligible for weight loss medications, patients must meet three criteria: failed weight loss goals by behavioral intervention alone, have a BMI ⥠27 with a weight-related health problem or BMI ⥠30, and must not be pregnant or trying to become pregnant. Regarding the first of these criteria, weight loss goals should be â¥1 pound of weight loss per week in the 1st month intervention and >5% body weight within the first 3-6 months.
Orlistat (Xenical, Alli), lorcaserin (Belviq), phentermine/topiramate (Qsymia), naltrexone/buproprion (Contrave), liraglutide (Saxenda), diethylpropion (Tenuate, Tenuate Dospan), phentermine (Adipex-P, Suprenza), benzphetamine (Didrex), and phendimetrazine (Bontril, Bontril ER) are all FDA-approved weight loss drugs. Selecting the most appropriate drug for a given patient depends on a number of factors related to the side-effect profiles, mechanisms of action, cost and weight loss interval, and the maximal duration of use of these weight loss drugs. Orlistat, for example, is a generally safe and effective drug, but only confers patients with modest weight loss over an extended period (approximately 4 years of use to achieve its maximal effects). Conversely, phentermine/topiramate gives patients up to a 10% reduction of body weight within one year, but at the cost of a fairly serious side effect profile (sympathomimetic, impairs cognition, causes depression, teratogenic). The sympathomimetic amines, benzphetamine, diethylpropion, phendimetrazine, and phentermine, are examples of short-term drugs that can only be used for 12 weeks …
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