Atypical idiopathic intracranial hypertension: normal BMI and older patients.

BACKGROUND: Idiopathic intracranial hypertension (IIH) typically affects young, obese women. We examined 2 groups of atypical patients with IIH: those with a normal body mass index (BMI) and those at least 50 years of age. METHODS: A retrospective cohort study of 407 consecutive adult patients with IIH with known BMI from 3 centers was undertaken. Demographics, associated factors, visual acuity, and visual fields were collected at presentation and follow-up. RESULTS: We identified 18 IIH patients (4%) with normal BMI and 19 (5%) aged 50 years or older at the time of diagnosis who were compared with the remainder of the cohort. Medication-induced IIH was more frequent in patients with IIH with normal BMI (28 vs 7%, p = 0.008). No patient with IIH with a normal BMI had severe visual loss in either eye (0 vs 17%, p = 0.09). Older patients with IIH had a lower BMI, but were still generally obese (33 vs 38, p = 0.04). Older patients were less likely to report headache as initial symptom (37 vs 76%, p < 0.001) and more likely to complain of visual changes (42 vs 21%, p = 0.03). Treatment of any type was less likely in older patients (significant for medications: 74 vs 91%, p = 0.004), and they were more likely to have persistent disc edema at last follow-up (median Frisén grade: 1 vs 0, p = 0.002), but had similar, if not better, visual outcomes compared with younger patients. A case-control study did not identify any new medication or risk factor associations. CONCLUSIONS: Patients with normal body mass index and those 50 years or older make up a small proportion of patients with idiopathic intracranial hypertension (IIH), but appear to have better visual outcomes than more typical patients with IIH.

Mitigating the health impacts of pollution from oceangoing shipping: an assessment of low-sulfur fuel mandates.

Concerns about health effects due to emissions from ships have magnified international policy debate regarding low-sulfur fuel mandates for marine fuel. Policy discussions center on setting sulfur content levels and the geographic specification of low-sulfur fuel use. We quantify changes in premature mortality due to emissions from ships under several sulfur emissions control scenarios. We compare a 2012 No Control scenario (assuming 2.7% or 27 000 ppm S) with three emissions control scenarios. Two control scenarios represent cases where marine fuel is limited to 0.5% S (5000 ppm) and 0.1% S (1000 ppm) content, respectively, within 200 nautical miles of coastal areas. The third control scenario represents a global limit of 0.5% S. We apply the global climate model ECHAMSSy-MESSy1-MADE to geospatial emissions inventories to determine worldwide concentrations of particular matter (PM2.5) from ocean going vessels. Using those PM2.5 concentrations in cardiopulmonary and lung cancer concentration-risk functions and population models, we estimate annual premature mortality. Without control, our central estimate is approximately 87 000 premature deaths annually in 2012. Coastal area control scenarios reduce premature deaths by approximately 33 500 for the 0.5% case and approximately 43 500 for the 0.1% case. Where fuel sulfur content is reduced globally to 0.5% S, premature deaths are reduced by approximately 41 200. These results provide important support that global health benefits are associated with low-sulfur marine fuels, and allow for relative comparison of the benefits of alternative control strategies.

Idiopathic intracranial hypertension in men.

OBJECTIVE: To compare the characteristics of idiopathic intracranial hypertension (IIH) in men vs women in a multicenter study. METHODS: Medical records of all consecutive patients with definite IIH seen at three university hospitals were reviewed. Demographics, associated factors, and visual function at presentation and follow-up were collected. Patients were divided into two groups based on sex for statistical comparisons. RESULTS: We included 721 consecutive patients, including 66 men (9%) and 655 women (91%). Men were more likely to have sleep apnea (24% vs 4%, p < 0.001) and were older (37 vs 28 years, p = 0.02). As their first symptom of IIH, men were less likely to report headache (55% vs 75%, p < 0.001) but more likely to report visual disturbances (35% vs 20%, p = 0.005). Men continued to have less headache (79% vs 89%, p = 0.01) at initial neuro-ophthalmologic assessment. Visual acuity and visual fields at presentation and last follow-up were significantly worse among men. The relative risk of severe visual loss for men compared with women was 2.1 (95% CI 1.4-3.3, p = 0.002) for at least one eye and 2.1 (95% CI 1.1-3.7, p = 0.03) for both eyes. Logistic regression supported sex as an independent risk factor for severe visual loss. CONCLUSION: Men with idiopathic intracranial hypertension (IIH) are twice as likely as women to develop severe visual loss. Men and women have different symptom profiles, which could represent differences in symptom expression or symptom thresholds between the sexes. Men with IIH likely need to be followed more closely regarding visual function because they may not reliably experience or report other symptoms of increased intracranial pressure.

Long-term follow-up of idiopathic intracranial hypertension: the Iowa experience.

OBJECTIVE: To evaluate recurrent or delayed worsening of papilledema and visual function in patients with idiopathic intracranial hypertension (IIH) followed for more than 10 years. METHODS: This is an Institutional Review Board approved retrospective chart review of 410 patients with the diagnosis of IIH evaluated at the University of Iowa Hospitals and Clinics from January 1984 to January 1996. Of the 410 patients, 20 patients with IIH who were followed over 10 years at the neuro-ophthalmology clinic met the inclusion criteria. Three neuro-ophthalmologists independently evaluated and graded the visual field examinations and optic disc stereo-photographs for each follow-up visit (median = 15). RESULTS: Of the 20 patients, 11 demonstrated a stable course of disease without worsening in papilledema or visual field, and 9 patients worsened after a stable course. Of these 9 patients, 6 patients experienced delayed worsening (range: 28 to 135 months from presentation) and 3 patients had recurrence after resolution of papilledema 12 to 78 months from initial resolution of the IIH. CONCLUSION: Idiopathic intracranial hypertension is a chronic condition that may worsen after a period of stability, warranting long-term follow-up.

Measurements of NOx emissions and in-service duty cycle from a towboat operating on the inland river system.

This paper describes measurements of NOx emissions from one engine on a commercial towboat operating on the Upper Ohio River system around the Port of Pittsburgh. Continuous measurements were made over a one-week period to characterize emissions during normal operations. The average NOx emission factor is 70 +/- 4.2 kg of NOx per t of fuel, similar to that of larger marine engines. A vessel-specific duty cycle is derived to characterize the towboat's operations; more than 50% of the time the vessel engines are at idle. Although recently promulgated EPA regulations apply only to new marine engines, these data provide insight into inland-river operations, which can be used to evaluate these regulations within the inland river context. This vessel operates as a courier service, scheduling pickups and deliveries of single- or multiple-barge loads per customers' requests; as many as 30% of the 277 towboats in the Pittsburgh region operate in this fashion. The EPA-prescribed ISO E3 duty cycle does not accurately describe inland-river operations of this towboat: its application overestimates actual NOx emissions by 14%. Only 41% of this vessel's operations fall within the Not-To-Exceed Zone defined by the EPA regulations, which limits the effectiveness of this component of the regulations to limit emissions from vessels that operate in a similar fashion.

Retinol-binding protein in idiopathic intracranial hypertension (IIH).

OBJECTIVE: We postulated that an alteration in endogenous vitamin A (retinol) metabolism plays a causal role in the pathogenesis of idiopathic intracranial hypertension (IIH). MATERIALS AND METHODS: Serum retinol was determined by a fluorometric method from 40 control subjects and 58 patients with idiopathic intracranial hypertension (IIH). Retinol binding protein (RBP) was also assayed by quantitative radial immunodiffusion in 17 control subjects and 30 patients with IIH. RESULTS: Mean retinol values were higher in the IIH group compared with the control group, but did not reach a significant level. However, seven of 30 patients with IIH had high RBP levels, but none of the control subjects did. CONCLUSION: This data suggests that IIH is associated with an abnormality in vitamin A metabolism that is linked to its transport system.

Visual perceptual abnormalities: hallucinations and illusions.

Visual perceptual abnormalities may be caused by diverse etiologies which span the fields of psychiatry and neurology. This article reviews the differential diagnosis of visual perceptual abnormalities from both a neurological and a psychiatric perspective. Psychiatric etiologies include mania, depression, substance dependence, and schizophrenia. Common neurological causes include migraine, epilepsy, delirium, dementia, tumor, and stroke. The phenomena of palinopsia, oscillopsia, dysmetropsia, and polyopia among others are also reviewed. A systematic approach to the many causes of illusions and hallucinations may help to achieve an accurate diagnosis, and a more focused evaluation and treatment plan for patients who develop visual perceptual abnormalities. This article provides the practicing neurologist with a practical understanding and approach to patients with these clinical symptoms.

Serum vitamin A concentration is elevated in idiopathic intracranial hypertension.

OBJECTIVE: The primary purpose was to investigate whether serum vitamin A concentration is associated with idiopathic intracranial hypertension (IIH). The secondary aim was to obtain pilot data regarding the amount of vitamin A ingested by patients and controls. BACKGROUND: Vitamin A is an attractive candidate mediator of IIH as many of the symptoms and signs of hypervitaminosis A mimic those of IIH. METHODS: We prospectively determined serum retinol and retinyl ester concentration in 16 women with IIH and 70 healthy young women. Using a survey instrument, we also determined the average daily vitamin A ingestion in a convenience sample of patients and controls. RESULTS: Serum retinol concentration was significantly higher in the patient group (median 752 ug/L) compared with the control group (median 530 ug/L), even after adjusting for age and body mass index (p < 0.001). Retinyl ester concentration, however, was similar in the patient (median 48 ug/L) and control (median 41 ug/L) groups (p = 0.32). There was no significant correlation between serum retinol concentration and body mass index in the patients (r = 0.16) or controls (r = -0.02). Finally, there was no significant difference in the amounts of vitamin A ingested by the patients or controls, although the small number of subjects in both groups reduced the power of this conclusion. CONCLUSIONS: Elevated serum retinol concentration is associated with IIH. Obesity, by itself, does not explain these higher levels. Patients may ingest an abnormally large amount of vitamin A, metabolize it abnormally, or be unusually sensitive to its effects. Alternatively, elevated level of serum retinol may reflect an epiphenomenon of another variable we did not measure or a nonspecific effect of elevated retinol binding capacity.

Segmental denervation and reinnervation of the iris sphincter as shown by infrared videographic transillumination.

OBJECTIVE: This study aimed to analyze the denervation and reinnervation history of individual segments of the iris sphincter in patients with Adie's syndrome. DESIGN: The irises of these patients were retroilluminated by shining an infrared-rich light through the lower eyelid and sclera and viewing the transilluminated iris from the front with an infrared-sensitive video camera. The irises of the same group of patients also were videotaped through a slit-lamp camera using routine frontal illumination. Both of these techniques also were used to examine a series of normal subjects. PARTICIPANTS: A total of 61 patients with Adie's syndrome or Adie's-like denervation of the iris sphincter (from surgery, trauma, or radiation) and 10 normal subjects were studied. MAIN OUTCOME MEASURES: Slit-lamp examination results of the segmental movement of the iris were compared to the infrared transillumination pattern of the iris sphincter before and during the light reflex, before and during the near-vision reaction, before and during eye movement, and before and after the application of dilute pilocarpine and 1% pilocarpine. RESULTS: Whenever an iris sphincter segment contracted, it also became denser by using these techniques. Reinnervated iris segments failed to contract to light but did contract and became denser with a near effort or with eye movement. Segments supersensitive to pilocarpine became denser than adjacent segments without supersensitivity, but atrophic-appearing segments looked translucent and thin, failing to become denser, even with 1% pilocarpine. CONCLUSIONS: The innervational history and current status of each clock-hour segment of the iris sphincter can be determined using this technique of videographic infrared transillumination, and the progression and pattern of iris denervation and reinnervation can be determined in patients with Adie's pupil. A miotic Adie's pupil that is "tonic," even in darkness, was found to be associated with a dense pattern of infrared transillumination in sphincter segments, which the authors interpret as being associated with a rich reinnervation from accommodative fibers. Segments that become densely reinnervated appear to lose their cholinergic supersensitivity.

Bilateral ptosis due to mesencephalic lesions with relative preservation of ocular motility.

Three cases of bilateral ptosis with relatively normal ocular motility are presented. In two of the patients, neuroimaging demonstrated lesions in the region of the third cranial nerve subnuclei. These unusual clinical presentations are due to isolated involvement of the central caudal nucleus supplying the bilateral levator muscles, with, virtually complete sparing of other third cranial nerve structures.

Optic nerve compression from a basal encephalocele.

A woman developed headaches, transient visual obscurations, anosmia, and decreased visual acuity. Ocular examination showed bilateral pulsatile proptosis and disc edema with choroidal folds. Standardized ophthalmic echography showed absence of bony orbital roofs, prominent dural pulsations, direct apposition of brain parenchyma and orbital tissues, and echographic signs suggesting bilateral optic nerve compression. CT and MRI showed a large defect in the floor of the anterior cranial fossa. The cribriform plate, both orbital roofs, and sphenoid bones were displaced by a large basal encephalocele. Clinical improvement followed reconstruction of the anterior cranial fossa and decompression of both optic nerves.

Neuro-ophthalmic complications of intracranial catheters.

We report four patients who sustained direct injury to the brain after insertion of intraventricular shunts and pressure monitoring lines, which resulted in permanent neuro-ophthalmic deficits. These included hemianopsia from an optic tract lesion, esotropia and residual bilateral facial paresis from dorsal pontine injury, unilateral blindness from damage to the optic nerve, and dorsal midbrain syndrome from catheter compression in the region of the posterior commissure. Although presumably rare, such injuries should be considered in diagnosing patients with neuro-ophthalmic complaints after insertion of such devices.

Cerebrospinal fluid diversion procedures in pseudotumor cerebri.

We reviewed the efficacy of CSF diversion for pseudotumor cerebri (PTC) in patients from six different institutions. Thirty-seven patients underwent a total of 73 lumboperitoneal shunts and nine ventricular shunts. Only 14 patients remained "cured" after a single surgical procedure. The average time between shunt insertion and shunt replacement was 9 months, although 64% of shunts lasted less than 6 months. Shunt failure (55%) and low-pressure headaches (21%) were the most common causes for reoperation. The vision of most patients improved (13) or stabilized (13) postoperatively. However, three who had initially improved subsequently lost vision. Six had a postoperative decrease in vision. Two patients improved in one eye but worsened postoperatively in the other. Four lost vision despite apparently adequate shunt function. Shunt failure with relapse of PTC occurred as late as 7 years after insertion. CSF diversion procedures have a significant failure rate as well as a high frequency of side effects.

The forgotten lumbar puncture.

Lumbar puncture is crucial in two distinct clinical situations in the diagnosis of the headache patient. The first is the patient who is suspected of having a symptomatic headache; the second is the patient with a chronic intractable or atypical headache disorder. This review discusses the usefulness of the lumbar puncture in the diagnosis of headache secondary to subarachnoid hemorrhage, meningitis, and intracranial hypotension and hypertension. The value of lumbar puncture in the presence of a normal CT/MRI scan is discussed.

Neurologic conditions presenting as psychiatric disorders.

Neurologic disease can present as a psychiatric disorder. Understanding underlying neuroanatomic function helps physicians to localize defects and search for treatable neurologic conditions. Neurologic conditions such as Huntington's chorea, Wilson's disease, Gille de la Tourette syndrome, brain tumors, encephalitis and meningitis, neurodegenerative conditions and metabolic or toxic conditions can have psychiatric manifestations.

A randomized, controlled trial of corticosteroids in the treatment of acute optic neuritis. The Optic Neuritis Study Group.

BACKGROUND AND METHODS: The use of corticosteroids to treat optic neuritis is controversial. At 15 clinical centers, we randomly assigned 457 patients with acute optic neuritis to receive oral prednisone (1 mg per kilogram of body weight per day) for 14 days; intravenous methylprednisolone (1 g per day) for 3 days, followed by oral prednisone (1 mg per kilogram per day) for 11 days; or oral placebo for 14 days. Visual function was assessed over a six-month follow-up period. RESULTS: Visual function recovered faster in the group receiving intravenous methylprednisolone than in the placebo group; this was particularly true for the reversal of visual-field defects (P = 0.0001). Although the differences between the groups decreased with time, at six months the group that received intravenous methylprednisolone still had slightly better visual fields (P = 0.054), contrast sensitivity (P = 0.026), and color vision (P = 0.033) but not better visual acuity (P = 0.66). The outcome in the oral-prednisone group did not differ from that in the placebo group. In addition, the rate of new episodes of optic neuritis in either eye was higher in the group receiving oral prednisone, but not the group receiving intravenous methylprednisolone, than in the placebo group (relative risk for oral prednisone vs. placebo, 1.79; 95 percent confidence interval, 1.08 to 2.95). CONCLUSIONS: Intravenous methylprednisolone followed by oral prednisone speeds the recovery of visual loss due to optic neuritis and results in slightly better vision at six months. Oral prednisone alone, as prescribed in this study, is an ineffective treatment and increases the risk of new episodes of optic neuritis.