Monthly Archives: July 2016

Users at Risk for Early Psychosis

unduhan-14Psychotic illness occurs significantly earlier among marijuana users, results of a meta-analysis suggest.

Data on more than 22,000 patients with psychosis showed an onset of symptoms almost three years earlier among users of cannabis compared with patients who had no history of substance use.

The age of onset also was earlier in cannabis users compared with patients in the more broadly characterized category of substance use, investigators reported online in Archives of General Psychiatry.

“The results of this study provide strong evidence that reducing cannabis use could delay or even prevent some cases of psychosis,” Dr. Matthew Large, of the University of New South Wales in Sydney, Australia, and co-authors wrote in conclusion.

“Reducing the use of cannabis could be one of the few ways of altering the outcome of the illness because earlier onset of schizophrenia is associated with a worse prognosis and because other factors associated with age at onset, such as family history and sex, cannot be changed.”

Psychosis has a strong association with substance use. Patients of mental health facilities have a high prevalence of substance use, which also is more common in patients with schizophrenia compared with the general population, the authors wrote.

Several birth cohort and population studies have suggested a potentially causal association between cannabis use and psychosis, and cannabis use has been linked to earlier onset of schizophrenia. However, researchers in the field remain divided over the issue of a causal association, the authors continued.

Attempts to confirm an earlier onset of psychosis among cannabis users have been complicated by individual studies’ variation in methods used to examine the association. The authors sought to resolve some of the uncertainty by means of meta-analysis.

A systematic search of multiple electronic databases yielded 443 potentially relevant publications. The authors whittled the list down to 83 that met their inclusion criteria: All the studies reported age at onset of psychosis among substance users and nonusers.

The studies comprised 8,167 substance-using patients and 14,352 patients who had no history of substance use. Although the studies had a wide range of definitions of substance use, the use was considered “clinically significant” in all 83 studies. None of the studies included tobacco in the definition of substance use.

The studies included a total of 131 patient samples.

Substance use included alcohol in 22 samples, cannabis in 41, and was simply defined as “substance use” in 68 samples.

Alcohol use was not significantly associated with earlier age at onset of psychosis.

On average, substance users were about 2 years younger than nonusers were. The effect of substance use on age at onset was greater in women than in men, but not significantly so. Heavy use was associated with earlier age at onset compared with light use and former use, but also not significantly different, the authors reported.

Pitchers Need Limits on Innings

To prevent serious arm injuries, young baseball pitchers should pitch no more than 100 innings a year, researchers said.

In a 10-year prospective study, boys who pitched more than 100 innings were almost four times more likely to undergo elbow or shoulder surgery or to retire because of injury, according to Dr. Glenn Fleisig, of the American Sports Medicine Institute in Birmingham, Ala., and colleagues.

The cumulative rate of serious injury was 14 percent in those who exceeded that number and 4 percent in those who did not, the researchers reported in the February issue of the American Journal of Sports Medicine.

“On the basis of these findings and review of the literature, we recommend that pitchers in high school and younger pitch no more than 100 innings in competition in any calendar year,” Fleisig and his colleagues wrote.

“Young pitchers who have not developed should be limited to even less, and no pitcher should continue to pitch when fatigued.”

In recent years, researchers have detected an increase in the numbers of younger pitchers who require shoulder and elbow surgery, including ulnar collateral ligament reconstruction, or Tommy John surgery.

Many doctors believe that the trend is related to the growth of year-round baseball leagues and showcases for professional scouts, which reduces the amount of downtime pitchers would normally have in the off-season.

A 1999 study linked the number of pitches thrown to elbow and shoulder pain — assumed to be a predictor of future injury. That and similar studies led youth baseball organizations, including Little League Baseball, to replace innings limits with pitch counts.

But no studies had established a relationship between throwing volume and injury risk.

To explore the risk factors for serious arm injuries — those requiring surgery or those resulting in retirement — Fleisig and his colleagues followed 481 male pitchers ages 9 to 14 for 10 years using annual telephone interviews; about two were still pitching in the final year of the study.

The researchers focused on total innings pitched in the previous year rather than pitch counts because most youth players and their families do not keep track of the numbers of balls thrown.

During the study, three of the boys had elbow surgery, seven had shoulder surgery, and 14 retired because of a throwing injury, resulting in a 10-year rate of serious injury of 5 percent.

The average age at the time of surgery was 17, and two boys underwent surgery before they turned 13.

The only significant risk factor for serious injury was pitching more than 100 innings in a calendar year.

There was a trend toward a greater likelihood of serious injury in boys who played both pitcher and catcher during the study period (11 percent versus 4 percent), but it fell short of statistical significance because of the small sample size, according to Fleisig and his colleagues.

“A baseball player may play multiple positions, but we discourage an individual from playing both pitcher and catcher,” they wrote.

iPad App for MRI

The FDA has moved into the “got an app for that” market by approving the first diagnostic radiology application for the iPhone and the iPad.

In announcing the approval, the FDA said the application can be used to view results of CT, MRI, and PET scans on the mobile devices and use those images to make diagnoses.

But the agency noted that the app was “not intended to replace full workstations and is indicated for use only when there is no access to a workstation.”

“This important mobile technology provides physicians with the ability to immediately view images and make diagnoses without having to be back at the workstation or wait for film,” said William Maisel, MD, MPH, chief scientist and deputy director for science in the FDA’s Center for Devices and Radiological Health in a statement.

The new “device,” which is designed for use with Apple products, is a software program called Mobile MIM, made by Cleveland’s MIM Software.

The software allows radiology images taken in the hospital or physician’s office to be “compressed for secure network transfer then sent to the appropriate portable wireless device,” according to the FDA statement.

The images are then viewed on the iPhone or iPad in a format that “allows the physician to measure distance on the image and image intensity values and display measurement lines, annotations and regions of interest.”

The FDA said it evaluated the app by testing its performance on a number of devices, measuring luminance, resolution, and noise against international standards and guidelines.

The FDA said it, “also reviewed results from demonstration studies with qualified radiologists under different lighting conditions. All participants agreed that the device was sufficient for diagnostic image interpretation under the recommended lighting conditions.”

In announcing the approval, the FDA noted that mobile devices have a wide range of variation in luminance even among the same model devices.

“The Mobile MIM application includes sufficient labeling and safety features to mitigate the risk of poor image display due to improper screen luminance or lighting conditions. The device includes an interactive contrast test in which a small part of the screen is a slightly different shade than the rest of the screen. If the physician can identify and tap this portion of the screen, then the lighting conditions are not interfering with the physician’s ability to discern subtle differences in contrast,” the FDA said.

MIM is including a safety guide within the application.