Serum vitamin A concentration is elevated in idiopathic intracranial hypertension

The Role and Mechanism of Retinol and Its Transformation Product, Retinoic Acid, in Modulating Oxidative Stress-Induced Damage to the Duck Intestinal Epithelial Barrier In Vitro

This study aimed to investigate the effects and mechanisms of retinol and retinoic acid on primary duck intestinal epithelial cells under oxidative stress induced by H2O2. Different ratios of retinol and retinoic acid were used for treatment. The study evaluated the cell morphology, viability, antioxidative capacity, and barrier function of cells. The expression of genes related to oxidative stress and the intestinal barrier was analyzed. The main findings demonstrated that the treated duck intestinal epithelial cells exhibited increased viability, increased antioxidative capacity, and improved intestinal barrier function compared to the control group. High retinoic acid treatment improved viability and gene expression, while high retinol increased antioxidative indicators and promoted intestinal barrier repair. Transcriptome analysis revealed the effects of treatments on cytokine interactions, retinol metabolism, PPAR signaling, and cell adhesion. In conclusion, this study highlights the potential of retinol and retinoic acid in protecting and improving intestinal cell health under oxidative stress, providing valuable insights for future research.

Association of serum retinol concentration with normal-tension glaucoma

OBJECTIVES

To evaluate the association between serum retinol concentration and normal-tension glaucoma (NTG).

METHODS

A total of 345 study subjects were recruited in a prospective cross-sectional study: 101 patients with NTG, 106 patients with high-pressure primary open-angle glaucoma (POAG) and 138 healthy control subjects. Serum retinol concentration in fasting blood samples was determined by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). All study subjects were given complete ophthalmic examinations and diagnosed by two glaucoma sub-specialists.

RESULTS

Serum retinol concentrations in NTG, POAG, and controls were 338.90 ± 103.23 ng/mL, 405.22 ± 114.12 ng/mL, and 408.84 ± 122.36 ng/mL respectively. NTG patients had lower serum retinol concentrations than POAG (p < 0.001) or healthy controls (p < 0.001). There was no statistical difference between the POAG and healthy controls (p = 0.780). Higher proportion of NTG patients (37.6%) than POAG (17.9%) or controls (21.7%) had serum retinol concentrations lower than 300 ng/mL. Serum retinol was positively correlated with optic nerve sheath diameter (ONSD) (r = 0.349, p = 0.001) in glaucoma patients and not associated with any other demographic features or ophthalmic biometric parameters in the NTG patients. Multivariate logistic regression showed that serum retinol (OR = 0.898, 95CI%: 0.851-0.947) was associated with incident NTG.

CONCLUSIONS

NTG patients had lower serum retinol concentrations. Serum retinol uniquely associated with NTG makes it a new potential option for the diagnosis and treatment of the disease.

An update on idiopathic intracranial hypertension in adults: a look at pathophysiology, diagnostic approach and management

Idiopathic intracranial hypertension is a neurological syndrome determined by a rise in intracranial pressure without a detectable cause. Course and prognosis may be changeable, requiring a multidisciplinary approach for its diagnosis and management. Although its precise pathogenesis is still unknown, many studies have been carried out to define the possible causal and associated factors, such as retinoids, steroid hormones, body mass index and recent weight gains, cytokines and adipokines levels. The clinical presentation can be variable including chronic headache, disturbance of vision, diplopia and tinnitus. Even if papilloedema is considered the most specific sign, it could not be observed in more than 5% of patients during the evaluation of the fundus oculi. Neuroradiological signs acquire greater importance in patients who do not present papilloedema and may suggest the diagnosis of idiopathic intracranial hypertension. Other assessments can be useful in the diagnostic process, such as optical coherence tomography, visual evoked potentials, ocular ultrasonography and fundus fluorescein angiography and autofluorescence. Nonetheless, cerebrospinal fluid pressure measurement is required to establish a definite diagnosis. Management may be different, since surgical procedures or lumbar punctures are often required when symptoms develop rapidly leading to a loss of visual function. Apart from these cases, patients can be treated with a pharmacological approach and low-calorie diet, but they also need to be monitored over time since relapses years later are not uncommon.

The role of intracranial pressure in glaucoma and therapeutic implications

Despite glaucoma being the second leading cause of blindness globally, its pathogenesis remains incompletely understood. Although intraocular pressure (IOP) contributes to glaucoma, and reducing IOP slows progress of the disease, some patients progress despite normal IOP (NTG). Glaucomatous damage causes characteristic cupping of the optic nerve where it passes through the lamina cribrosa. There is evidence that cerebrospinal fluid (CSF) within the optic nerve sheath has a different composition from CSF surrounding the brain. Furthermore, fluctuations in CSF flow into the optic nerve sheath may be reduced by trabeculae within the sheath, and on standing intracranial pressure (ICP) within the sheath is stabilised at around 3 mmHg due to orbital pressure. Blood pressure has been linked both to glaucoma and ICP. These facts have led some to conclude that ICP does not play a role in glaucoma. However, according to stress formulae and Laplace's Law, stress within the lamina cribrosa is dependent on the forces on either side of it, (IOP and ICP), and its thickness. On lying flat at night, ICP between the brain and optic nerve sheath should equalise. Most evidence suggests ICP is lower in glaucoma than in control groups, and that the lamina cribrosa is thinner and more posteriorly displaced in glaucoma. Subjects who have had ICP reduced have developed signs of glaucoma. This review finds most evidence supports a role for low ICP in the pathogenesis of glaucoma. Caffeine, theophylline and vitamin A may increase ICP, and could be new candidates for an oral treatment.

Pseudotumor Cerebri Syndrome with Resolution After Discontinuing High Vitamin A Containing Dietary Supplement: Case Report and Review

A 24-year-old non-obese, but slightly overweight, female presented with a two-week history of progressive severe headache associated with two days of blurry vision. Clinical exam was significant for bilateral papilledema and an enlarged blind spot on visual field testing. Contrast enhanced MRI head revealed no space occupying lesion. A lumbar puncture revealed an elevated opening pressure of 38 cm H₂O with normal cerebrospinal fluid composition leading to a diagnosis of pseudotumor cerebri syndrome (PTCS). The patient lacked the typical risk factors of high body mass index or obvious antecedent medications; however, on subsequent questioning, she was chronically ingesting a high vitamin A containing weight loss dietary supplement (Thrive W® - Table 1), which we believe had caused intracranial hypertension. Discontinuation of the diet pill and treatment with acetazolamide led to marked improvement of her PTCS. This case highlights the fact that non-traditional products or medications with high vitamin A may cause pseudotumor cerebri, which treating physicians should assess for while dealing with non-obese PTCS patients.

Impaired cerebrospinal fluid pressure

Abnormalities of cerebrospinal fluid (CSF) pressure are relatively common and may lead to a variety of symptoms, with headache usually being the most prominent one. The clinical presentation of alterations in CSF pressure may vary significantly and show a striking similitude to several primary headache syndromes. While an increase in CSF pressure may be of primary or secondary origin, a pathologic decrease of CSF pressure is usually the result of a meningeal rupture with a resulting leakage of CSF. The pathophysiologic mechanisms of idiopathic intracranial hypertension (IIH) remain largely unknown. However recent evidence indicates that an abnormality in CSF outflow and absorption is likely to play a significant role. Treatment usually consists of a combination of weight loss and a pharmacologic approach using carbonic anhydrase inhibitors. Recent results of the first randomized, double-blind, placebo-controlled trial (RCT) with acetazolamide proved its efficacy in reducing headache and visual disturbances. Clinical evidence suggests efficacy for topiramate and furosemide but no RCT has been conducted to date to confirm these results. In contrast to IIH, spontaneous intracranial hypotension frequently remits spontaneously without specific treatment. If necessary, treatment options range from conservative methods to epidural blood or fibrin sealant patches and surgical interventions.

Choroid plexus aquaporin 1 and intracranial pressure are increased in obese rats: towards an idiopathic intracranial hypertension model?

BACKGROUND/OBJECTIVES

Idiopathic intracranial hypertension (IIH) is a condition of increased intracranial pressure (ICP) without identifiable cause. The majority of IIH patients are obese, which suggests a connection between ICP and obesity. The aim of the study was to compare ICP in lean and obese rats. We also aimed to clarify if any ICP difference could be attributed to changes in some well-known ICP modulators; retinol and arterial partial pressure of CO₂ (pCO₂). Another potential explanation could be differences in water transport across the choroid plexus (CP) epithelia, and thus we furthermore investigated expression profiles of aquaporin 1 (AQP1) and Na/K ATPase.

METHODS

ICP was measured in obese and lean Zucker rats over a period of 28 days. Arterial pCO₂ and serum retinol were measured in serum samples. The CPs were isolated, and target messenger RNA (mRNA) and protein were analyzed by quantitative PCR and western blot, respectively.

RESULTS

Obese rats had elevated ICP compared to lean controls on all recording days except day 0 (P<0.001). Serum retinol (P=0.35) and arterial pCO₂ (P=0.16) did not differ between the two groups. Both AQP1 mRNA and protein levels were increased in the CP of the obese rats compared to lean rats (P=0.0422 and P=0.0281). There was no difference in Na/K ATPase mRNA or protein levels (P=0.2688 and P=0.1304).

CONCLUSION

Obese Zucker rats display intracranial hypertension and increased AQP1 expression in CP compared to lean controls. The mechanisms behind these changes are still unknown, but appear to be unrelated to altered pCO₂ levels or retinol metabolism. This indicates that the increase in ICP might be related to increased AQP1 levels in CP. Although further studies are warranted, obese Zucker rats could potentially model some aspects of the IIH pathophysiology.

Role of vitamin A metabolism in IIH: Results from the idiopathic intracranial hypertension treatment trial

INTRODUCTION

Vitamin A and its metabolites (called retinoids) have been thought to play a role in the development of idiopathic intracranial hypertension (IIH). The IIH Treatment Trial (IIHTT) showed the efficacy of acetazolamide (ACZ) in improving visual field function, papilledema grade, quality of life and cerebrospinal fluid (CSF) pressure. We postulated that IIH patients would demonstrate elevated measures of vitamin A metabolites in the serum and CSF.

METHODS

Comprehensive measures of serum vitamin A and its metabolites were obtained from 96 IIHTT subjects, randomly assigned to treatment with ACZ or placebo, and 25 controls with similar gender, age and body mass index (BMI). These included retinol, retinol binding protein, all-trans retinoic acid (ATRA), alpha- and beta-carotenes, and beta-cryptoxanthin. The IIHTT subjects also had CSF and serum vitamin A and metabolite measurements obtained at study entry and at six months.

RESULTS

At study entry, of the vitamin A metabolites only serum ATRA was significantly different in IIHTT subjects (median 4.33nM) and controls (median 5.04nM, p=0.02). The BMI of IIHTT subjects showed mild significant negative correlations with serum ATRA, alpha- and beta-carotene, and beta-cryptoxanthin. In contrast, the control subject BMI correlated only with serum ATRA. At six months, the serum retinol, alpha-carotene, beta-carotene, and CSF retinol were increased from baseline in the ACZ treated group, but only increases in alpha-carotene (p=0.02) and CSF ATRA (p=0.04) were significantly greater in the ACZ group compared with the placebo group. No other vitamin A measures were significantly altered over the six months in either treatment group. Weight loss correlated with only with the change in serum beta-carotene (r=-0.44, p=0.006) and the change in CSF retinol (r=-0.61, p=0.02).

CONCLUSION

Vitamin A toxicity is unlikely a contributory factor in the causation of IIH. Our findings differ from those of prior reports in part because of our use of more accurate quantitative methods and measuring vitamin A metabolites in both serum and CSF. ACZ may alter retinoid metabolism in IIH patients.

The idiopathic intracranial hypertension treatment trial: design considerations and methods

BACKGROUND

The objectives of this study were to present the rationale for the main aspects of the study design and describe the trial methodology for the Idiopathic Intracranial Hypertension Treatment Trial (IIHTT).

METHODS

Eligible candidates with mild visual field loss (automated perimetric mean deviation [PMD] -2 to -7 dB) were randomized to receive either acetazolamide or matching placebo tablets. Randomized participants were offered participation in a supervised dietary program. The primary outcome variable, PMD, was measured at 6 months. Additionally, cerebrospinal fluid from subjects and serum from study participants and matched controls were collected for genetic analysis and vitamin A studies. An ancillary optical coherence substudy was added to investigate the changes of papilledema in the optic nerve head and retina that correlate with Frisén grading, visual field deficits, and low-contrast visual acuity.

RESULTS

The randomized trial entered 165 participants from March 17, 2010, through November 27, 2012, from the United States and Canada. The primary outcome (month 6) visits were successfully completed by June 15, 2013. Blood specimens were obtained from 165 controls without IIH to investigate vitamin A metabolism and genetic markers of potential risk factors for IIH.

CONCLUSIONS

The IIHTT is the first randomized, double-masked placebo-controlled trial to study the effectiveness of medical treatment for patients with IIH.

Idiopathic intracranial hypertension

Background

Idiopathic intracranial hypertension or pseudotumour cerebri is primarily a disorder of young obese women characterised by symptoms and signs associated with raised intracranial pressure in the absence of a space-occupying lesion or other identifiable cause.

Summary

The overall incidence of idiopathic intracranial hypertension is approximately two per 100,000, but is considerably higher among obese individuals and, given the global obesity epidemic, is likely to rise further. The pathophysiology of this condition is poorly understood, but most theories focus on the presence of intracranial venous hypertension and/or increased cerebrospinal fluid outflow resistance and how this relates to obesity. A lack of randomised clinical trials has resulted in unsatisfactory treatment guidelines and although weight loss is important, especially when used in conjunction with drugs that reduce cerebrospinal fluid production, resistant cases remain difficult to manage and patients invariably undergo neurosurgical shunting procedures. The use of transverse cerebral sinus stenting remains contentious and long-term benefits are yet to be determined.

Conclusion

An understanding of the clinical features, diagnostic work-up and therapeutic options available for patients with idiopathic intracranial hypertension is important both for neurologists and ophthalmologists as visual loss maybe permanent if untreated.

The role of aquaporin-1 in idiopathic and drug-induced intracranial hypertension

Idiopathic intracranial hypertension is a common disorder affecting mainly healthy, young, overweight women. The pathogenesis of this condition is unknown, but it has been shown to follow treatment with several compounds including corticosteroids and vitamin A derivatives. This paper will offer a novel hypothesis and insight on the pathogenesis of drug induced intracranial hypertension following a review and analysis of the literature. Both corticosteroids and vitamin A derivatives have been shown to upregulate the expression of aquaporin 1, a water channel protein. Aquaporin 1 is widely distributed in the human brain and is associated with water secretion into the subarachnoid space. Aquaporin 1 was also shown to participate in the regulation of weight. Agents used for treating idiopathic intracranial hypertension reduce aquaporin 1 expression. Based on these observations, we propose that aquaporin 1 has a pathogenetic role in drug induced idiopathic intracranial hypertension. Over expression of this gene causes increased intracranial pressure, and downregulation reduces pressure and alleviates the symptomatology and complications of idiopathic intracranial hypertension.

Idiopathic intracranial hypertension following spinal deformity surgery in children

Idiopathic intracranial hypertension (IIH) after pediatric spinal deformity surgery has not been previously reported. The authors conducted a retrospective analysis of more than 1500 pediatric spinal surgeries performed between 1992 and 2011. From their analysis, they report on 3 adolescent patients who underwent uncomplicated segmental spinal instrumentation for pediatric spinal deformity correction and subsequently developed features of IIH. The common variables in these 3 patients were adolescent age, spinal deformity, being overweight, symptom onset within 2 weeks postoperatively, significant estimated blood loss, and intraoperative use of ε-aminocaproic acid (antifibrinolytic) injection. The authors postulate that the development of IIH could be the result of venous outflow obstruction due to derangement of the epidural venous plexus during surgery. The use of ε-aminocaproic acid could potentially have the risk of causing IIH, probably mediated through hyperfibrinogenemia, although there have not been published cases in the neurosurgical, orthopedic, cardiac, or general surgical literature. Idiopathic intracranial hypertension after spinal deformity correction is a condition that should be recognized by neurosurgeons and orthopedic surgeons, because appropriate intervention with early medical therapy can lead to a satisfactory clinical outcome.

Idiopathic intracranial hypertension in children: a review and algorithm

This updated review of pediatric idiopathic intracranial hypertension focuses on epidemiology, clinical presentations, diagnostic criteria, evaluation, clinical course, and treatment. General guidelines for the clinical management of idiopathic intracranial hypertension are discussed. A new algorithm outlines an efficient management strategy for the initial diagnostic evaluation of children with signs or symptoms of intracranial hypertension. This algorithm provides a systematic approach to initial evaluation and management, and identifies important decision-making factors. The risk of permanent visual loss with idiopathic intracranial hypertension necessitates a prompt, thorough collaborative approach in the management of patients. Although idiopathic intracranial hypertension has been recognized for over a century, the need remains for prospectively collected data to promote a better understanding of the etiology, risk factors, evaluative methods, and effective treatments for children with this syndrome.

Idiopathic intracranial hypertension in two patients with Alagille syndrome

Alagille syndrome is an autosomal dominant condition with incomplete penetrance that is associated mostly with hepatic, cardiac, and skeletal abnormalities. In addition, the association of Alagille syndrome with ocular abnormalities is well known and is considered one of the characteristic features of this condition. Most commonly, posterior embryotoxon, glaucoma, or retinopathy has been identified in these children. The authors present 2 patients with Alagille syndrome who, before the age of 3 years old, developed idiopathic intracranial hypertension with documented increased intracranial pressure by lumbar puncture and papilledema, which was responsive to acetazolamide.

Cerebrospinal fluid markers of idiopathic intracranial hypertension: is the renin-angiotensinogen system involved?

BACKGROUND

The causes underlying idiopathic intracranial hypertension (IIH) are poorly understood.

METHODS

To identify disease-related biomarkers that could offer a new insight into IIH pathology, we analyzed the cerebrospinal fluid (CSF) of 18 patients with IIH and 18 controls using two-dimensional fluorescence differential in-gel electrophoresis (2-D DIGE).

RESULTS

We found six proteins that were upregulated in IIH (sterol regulatory element-binding protein 1, zinc-alpha-2-glycoprotein, immunoglobulin heavy constant alpha 1 [IGHA1], alpha-1-antitrypsin [SERPINA1], serotransferrin, haptoglobin) and four proteins that were downregulated (hemopexin, angiotensinogen, vitamin-D-binding protein, transthyretin). The validity of our approach was confirmed for one candidate protein (angiotensinogen). To account for a dependency from blood-CSF barrier function, the ratio of angiotensinogen and albumin CSF-to-serum quotients (Qang/Qalb) was determined, which confirmed the downregulation of angiotensinogen in IIH (p = .04).

CONCLUSION

Previous studies showed the intrinsic renin-angiotensin system (RAS) to regulate choroid plexus blood flow and CSF production. Altered levels of angiotensinogen could indicate an imbalance of the RAS in IIH that may provide new targets for therapeutic intervention.

Pseudotumor cerebri presenting as headache

Pseudotumor cerebri (PTC) is characterized by intracranial hypertension without ventriculomegaly, in the absence of a mass lesion or meningeal process. When there is no secondary cause, it is termed 'idiopathic intracranial hypertension'. Headache is the most common symptom of PTC, present in over 90% of patients. The headache is often disabling and nonspecific in character; thus, ophthalmoscopy is imperative for all patients being evaluated for headache. Visual loss is the major morbidity of PTC, requiring prompt diagnosis and treatment to prevent permanent deficits. Medical and surgical treatments are employed, although evidence-based treatment guidelines do not exist. This review discusses the diagnosis, differential diagnosis and management strategies for patients with PTC.

Pediatric idiopathic intracranial hypertension

Our understanding of pediatric idiopathic intracranial hypertension has been refined since Dr. Simmons Lessell's review in 1992. The use of rigorous methodologies and standard definitions in recent studies has demonstrated distinct demographic trends. Specifically, the incidence of idiopathic intracranial hypertension seems to be increasing among adolescent children, and among older children its clinical picture is similar to that of adult idiopathic intracranial hypertension (female and obese). Within younger age groups there are more boys and nonobese children who may develop idiopathic intracranial hypertension. The pathogenesis of the disease has yet to be elucidated. Idiopathic intracranial hypertension among young children has been associated with several new etiologies, including recombinant growth hormone and all-trans-retinoic acid. More modern neuroimaging techniques such as MRI and MRI-venograms are being used to exclude intracranial processes. Although most cases of pediatric idiopathic intracranial hypertension improve with medical treatment, those who have had visual progression despite medical treatment have undergone optic nerve sheath fenestration and lumboperitoneal shunting. Because idiopathic intracranial hypertension in young children appears to be a different disorder than in adolescents and adults, separate diagnostic criteria for younger children are warranted. We propose new criteria for pediatric idiopathic intracranial hypertension in which children should have signs or symptoms consistent with elevated intracranial pressure, be prepubertal, have normal sensorium, can have reversible cranial nerve palsies, and have an opening cerebrospinal fluid pressure greater than 180 mm H(2)O if less than age 8 and papilledema is present, but greater than 250 mm H(2)0 if age 8 or above or less than 8 without papilledema.

Exercise-induced esotropia

The authors evaluated a 34-year-old man with exercise-induced diplopia. The diagnostic testing that led to this conclusion is discussed. To the authors' knowledge, this is a rarely reported condition that warrants discussion.

What is new about idiopathic intracranial hypertension? An updated review of mechanism and treatment

Idiopathic intracranial hypertension (IIH) is the syndrome of raised intracranial pressure without clinical, laboratory or radiological evidence of intracranial pathology. IIH is a relatively rare disease but rapidly increasing incidence is reported due to a global increasing incidence of obesity. Disease course is generally said to be self-limiting within a few months. However, some patients experience a disabling condition of chronic severe headache and visual disturbances for years that limit their capacity to work. Permanent visual defects are serious and not infrequent complications. The pathophysiology of IIH is still not fully understood. Advances in neuroimaging techniques have facilitated the exclusion of associated conditions that may mimic IIH. No causal treatment is yet known for IIH and existing treatment is symptomatic and rarely sufficient. The aim of this review is to provide an updated overview of this potentially disabling disease which may show a future escalating incidence due to obesity. Theories of pathogenesis, diagnostic criteria and treatment strategies are discussed.

Idiopathic intracranial hypertension

Idiopathic intracranial hypertension is common in obese women and can lead to significant visual impairment. First described more than 100 years ago, the cause of the disorder remains unknown. Despite a multitude of proposed links, the aetiology has never been established. Impairment of cerebrospinal-fluid reabsorption is the most likely underlying pathophysiological cause of the raised pressure, but this notion has yet to be proven. Cerebral venous sinus abnormalities associated with the disorder need further exploration. Although the major symptoms of headache and visual disturbance are well documented, most data for disease outcome have been from small retrospective case series. No randomised controlled trials of treatment have been done and the management is controversial. The importance of weight loss needs clarification, the role of diuretics is uncertain, and which surgical intervention is the most effective and safe is unknown. Prospective trials to examine these issues are urgently needed.

Medication-induced intracranial hypertension in dermatology

Pseudotumor cerebri (PTC) is a syndrome of intracranial hypertension that is idiopathic or from an identified secondary cause. It is characterized by headaches and visual manifestations. The hallmark of PTC is papilledema and the feared consequence is visual loss that may be severe and permanent. The idiopathic form generally occurs in obese women of childbearing age. Various medications may produce PTC in patients at any age, including children. Several medications used in dermatology, particularly those used in the treatment of acne vulgaris, are associated with PTC. There is a strong association with tetracycline usage. Minocycline and doxycycline have also been linked to PTC, although there are relatively few reported cases. PTC has also been described with retinoids, including vitamin A (retinol) and isotretinoin. Although corticosteroids are often used to lower intracranial pressure acutely, corticosteroid withdrawal after long-term administration may induce increased intracranial pressure. A high index of suspicion, early diagnosis and treatment generally yield a good prognosis.

Idiopathic Intracranial Hypertension

The syndrome of intracranial hypertension without structural brain or cerebrospinal fluid abnormalities and without identifiable cause, now most appropriately termed idiopathic intracranial hypertension, was described over a century ago. Although the pathogenesis of this condition remains unknown, diagnostic and therapeutic developments during the past two decades have substantially advanced patient management.

Pseudotumor cerebri

Pseudotumor cerebri (PTC) is a syndrome of increased intracranial pressure without hydrocephalus or mass lesion and with normal cerebrospinal fluid (CSF) composition. Although often considered to be "idiopathic," detailed investigation has revealed a high incidence of venous outflow abnormalities in PTC syndrome patients. The thought that elevated intracranial venous sinus pressure is a "universal mechanism" for PTC syndrome of varying etiologies has been called into question by a study indicating that the increased venous pressure in idiopathic PTC patients is caused by the elevated intracranial pressure and not the reverse, suggesting that "the chicken is the CSF pressure elevation and the egg is the venous sinus pressure elevation." Vitamin A toxicity may play a role in the pathogenesis of idiopathic PTC. The treatment of PTC has two major goals: the alleviation of symptoms and preservation of visual function. When medical therapy fails or when visual dysfunction deteriorates, surgical therapies for PTC should be considered. The two main procedures performed include lumboperitoneal shunt and optic nerve sheath fenestration. Because of the association of PTC with venous sinus hypertension, some authors are considering venous sinus stenting for refractory cases of PTC. It is still unclear if primary treatment of the observed venous stenosis benefits patients with idiopathic PTC. This should be no surprise, as it is not certain whether the stenoses are the cause or the result of idiopathic PTC.

Is there a subtype of developmental Parkinson's disease?

Evidence accumulates suggesting that environmental factors including viral and risk factors associated with pregnancy and birth-giving, may increase the incidence of hypokinesia/parkinsonism in early life, or PD in later life. Such environmental pre-, peri- or postnatal stress may lead to disturbances in the developing brain and malformations in regions of particular interest and associated with PD. Genetic predisposition to hypoactivity plus environmental effects may lead to reorganization of brain circuitry including changes in monoaminergic and/or EAA systems, leading to a subtype of PD, i.e. genetic, drug induced, viral, developmental and other possible subtypes. The spectrum disorder of PD is going to be further substantiated into various etiopathologically verifyable subgroups.

Vitamin A in the cerebrospinal fluid of patients with and without idiopathic intracranial hypertension

We quantified vitamin A in the cerebrospinal fluid of patients with idiopathic intracranial hypertension, elevated intracranial pressure of other causes and normal intracranial pressure. Vitamin A could be detected by high-pressure liquid chromatography in most of the specimens. There was a significantly higher level of vitamin A in the cerebrospinal fluid of some patients with idiopathic intracranial hypertension. Vitamin A toxicity may play a role in the pathogenesis of idiopathic intracranial hypertension.

Idiopathic Intracranial Hypertension

Idiopathic intracranial hypertension (IIH), also known as pseudotumor cerebri, can be a serious vision-threatening disease. Visual acuity, visual fields, and ocular fundus appearance should be followed closely in all patients with IIH. Obese patients with IIH should be encouraged to lose weight. Medications that might cause or exacerbate IIH should be identified and discontinued if possible. Mild headaches can be treated with nonsteroidal anti-inflammatory drugs (NSAIDs) or migraine prophylactic agents. Some patients may not require additional treatment if they are otherwise asymptomatic and have no evidence of vision loss. Symptomatic patients (significant headache, visual complaints, tinnitus) or patients with visual field or acuity loss should be treated initially with acetazolamide. Furosemide may be a useful second-line agent. If vision loss is progressive despite maximal medical therapy or severe at the time of diagnosis, surgical intervention may be required. Optic nerve sheath fenestration is effective and safe, and may be repeated if initially unsuccessful. Lumboperitoneal shunting is also an option, especially if symptoms of headache are prominent and refractory to medical therapy, but it has significant complication and failure rates. Bariatric surgery can be an effective treatment for IIH in severely obese patients, but is not a useful acute intervention. Special issues must be considered when treating IIH in children or pregnant women.

Hepatic hydrothorax associated with vitamin a toxicity

We report the first case of an adult presenting with respiratory symptoms caused by hepatic hydrothorax secondary to vitamin A intoxication. The patient was a 52-year-old woman who presented to the hospital with progressive dyspnea. Evaluation demonstrated mild elevation of her liver function tests, ascites, and a right pleural effusion. The patient consumed a variety of vitamins, including vitamin A. Her estimated vitamin A intake was at least 162,300,000 international units (IU) during 18 years. She dramatically escalated her dose the year before admission for a total acute dose of 98,550,000 IU, with a daily intake of 270,000 IU. The recommended daily allowance is 4,000 IU. A transjugular liver biopsy revealed histopathologic changes consistent with vitamin A toxicity: hypertrophy and hyperplasia of hepatic stellate cells, focal pericellular fibrosis, mild perivenular fibrosis, and minimal, predominantly microvesicular steatosis. Despite the absence of cirrhosis, pressure readings demonstrated portal hypertension. During her hospitalization, the patient's symptoms and biochemical profile improved. As the large and generally unregulated United States dietary supplement industry continues to grow, it is increasingly likely that individuals will present with the signs and symptoms of vitamin excess rather than vitamin deficiency. Physicians need to remain alert to the varied presentations and toxic manifestations of excessive vitamin use.

A new classification and a synergetical pattern in intracranial hypertension

Intracranial hypertension develops from the initial cerebral effect of increased intracranial pressure and becomes symptomatical; then it acquires its individuality, surpassing the initial disease. The intracranial hypertension syndrome corresponds to the stage at which the increases in intracranial pressure (ICP) can be compensated and the ICH disease is in its acute form, equivalent to a decompensated ICH syndrome. Based on the etiopathogenesis of intracranial hypertension, a new classification is proposed: parenchymatous intracranial hypertension with an intrinsic cerebral cause; vascular intracranial hypertension, which has its etiology in disorders of the cerebral blood circulation; and essential or idiopathic intracranial hypertension, the former pseudotumor cerebri, an incomplete ICH syndrome. A synergetical pattern of the ICH is based on the relation between ICP and the period of high-pressure action: the critical pressure--time fluctuation causes the autoregulation of the cerebral blood flow to decrease or determines the brain herniation. The decompensation is a state of instability and appears when the intrinsic ratio of pressure--time fluctuation is changed: the high ICP lasts longer than the corresponding normal ICP, or the ICP is higher than the one that normally lasts the same period of time.

New developments in idiopathic intracranial hypertension

This review highlights recent additions to the literature regarding the diagnosis, evaluation, and management of idiopathic intracranial hypertension (pseudotumor cerebri). Unique features of pediatric pseudotumor cerebri are addressed as well.

Idiopathic intracranial hypertension and hemophilia A

OBJECTIVE

A patient with hemophilia A and long-standing recurrent symptoms of idiopathic intracranial hypertension is described. During his relapses, he experienced headache, and attention and language disturbance, but no visual symptoms.

BACKGROUND

Hemophilia A is a rare inherited coagulation disorder secondary to factor VIII deficiency. Idiopathic intracranial hypertension has been reported in association with prothrombotic conditions and iron deficiency anemia, but not in patients with hemophilia A. Recurrent or chronic headache is not a typical symptom of hemophilia, but headache is a presenting sign of intracranial bleed in persons with hemophilia.

METHODS

Medical history review, clinical neurologic examination, brain magnetic resonance imaging, computed head tomography, and electroencephalogram were performed.

RESULTS

Neurologic examination revealed bilateral papilledema during relapses of idiopathic intracranial hypertension. Multiple lumbar punctures preceded by the intravenous administration of factor VIII early in the course of the illness confirmed the presence of elevated cerebrospinal fluid pressures and absence of subarachnoid blood. He had no complications from lumbar punctures. Initial electroencephalograms showed background slowing but later normalized. Magnetic resonance imaging of the brain and computerized tomography of the head were normal. Relapses of idiopathic intracranial hypertension were eventually controlled with the administration of acetazolamide.

CONCLUSION

Idiopathic intracranial hypertension may develop in patients with hemophilia A in the absence of visual symptoms. Therapeutic and diagnostic lumbar punctures were safe to perform on this patient, following the administration of factor VIII.

Serum retinyl esters are not associated with biochemical markers of liver dysfunction in adult participants in the third National Health and Nutrition Examination Survey (NHANES III), 1988--1994

BACKGROUND

Serum retinyl ester concentrations are elevated in hypervitaminosis A. It was suggested that retinyl esters >10% of total serum vitamin A indicate potential hypervitaminosis, but this cutoff was derived from small clinical samples that may not be representative of the general population.

OBJECTIVE

We sought to examine the distribution of serum retinyl ester concentrations and associations between retinyl ester concentrations and biochemical markers of liver dysfunction in a nationally representative sample.

DESIGN

We assessed the associations between serum retinyl ester concentrations and 5 biochemical indexes of liver dysfunction by using multivariate linear and multiple logistic regression techniques and controlling for age, sex, use of supplements containing vitamin A, alcohol consumption, smoking status, and use of exogenous estrogens in 6547 adults aged > or =18 y in the third National Health and Nutrition Examination Survey (NHANES III), 1988--1994.

RESULTS

Thirty-seven percent of the sample had serum retinyl ester concentrations >10% of total serum vitamin A and 10% of the sample had serum retinyl esters >15% of total vitamin A. We found no associations between serum retinyl ester concentrations and 1) concentrations of any biochemical variable (multiple linear regression) or 2) risk of having biochemical variables above the reference range (multiple logistic regression). We did not find a serum retinyl ester value with statistically significant sensitivity and specificity for predicting increases in biochemical indexes of liver dysfunction.

CONCLUSIONS

The prevalence of serum retinyl ester concentrations >10% of the total vitamin A concentration in the NHANES III sample was substantially higher than expected but elevated retinyl ester concentrations were not associated with abnormal liver function.

Recurrence of idiopathic intracranial hypertension after weight loss: the carrot craver

PURPOSE

To describe a patient with stable idiopathic intracranial hypertension whose papilledema worsened.

METHOD

Case report.

RESULTS

A patient with documented idiopathic intracranial hypertension had resolution of disc edema with weight loss. Recurrence of papilledema led to the discovery that she consumed large quantities of raw carrots to help maintain her weight. Her increased vitamin A levels normalized, and the disc edema resolved when she stopped eating carrots.

CONCLUSION

Patients with idiopathic intracranial hypertension should be counseled regarding carrot intake.