I will open this post with the bottom line. No one has the definitive answer to this question. Yet. But interesting information can be found in a study published last month in The American Journal of Psychiatry. This study suggests that ADHD in adults does Continue reading
You are all familiar with a scourge that has plagued mankind for centuries without relief in sight. It has attacked humans of all ages but predominantly targets children. It is currently the source of many missed school days as well as parental and school Continue reading
The Biologic Effects of Ionizing Radiation report was initially requested by the U.S. Environmental Protection Agency in 1996. Since then, there have been several revisions of the BEIR report, the last being the BEIR VII Report in 2005. BEIR VII was different in that it also looked at the effects of low dose (<100 MSv) radiation on humans.
BEIR VII estimated a 1:1000 risk for cancer from one 10 mSv exposure to radiation. This is the radiation exposure from one abdominal, pelvic, or chest CT. These are imaging studies we order very commonly in our practices. In fact, there were over 70 million CT scans ordered in the United States in 2007 with projections that this may cause 29,000 future cancers.
No one really knows whether there is significant risk from one CT scan. These estimates of risk are based on an analysis of large populations over time using a linear non-threshold extrapolation. However, even if the risk from one scan is small, it is not insignificant and people are exposed to so many studies over a lifetime.
Background exposure to natural radiation in the United States is about 3 mSv per year (mostly from radon). In 1980, the average radiation dose per person in the U.S. from all sources was 3.6 mSv per year. However, by 2007, the average dose in the U.S. had nearly doubled to 6.2 mSv per year. CT scans have become the biggest source of radiation exposure to humans after background radiation.
The risk of cancer varies by age and gender. The risk of cancer is much higher for those under 20 years of age and for females. We need to be especially careful in imaging children. There are over 7 million CT scans performed annually on children in the U.S. Pediatric radiologists practice ALARA (as low as reasonably achievable) in imaging children, but nothing is better than judicious ordering to protect our children.
Estimated life-time risk of cancer, BEIR VII Phase 2, 2006
The radiation dose our patients receive varies by the type of study. Although plain films do not expose our patients to large doses of radiation, a CT of the abdomen or a barium enema is equivalent to about 750 chest x-rays, or more than 3 years of background radiation.
So yes, we need to be careful in ordering CT scans or other high-dose radiation imaging for our patients. This is our problem since the best predictor of radiation exposure in a population is the number of physicians in practice in that community.
Jim Cotter, MD MPH
You recall that Part I of this blog briefly referenced several recent developments in infectious diseases. Part II, here, will delve into a few that deserve greater attention.
Hepatitis C – There has been a revolution in the treatment of HCV that has great Continue reading
I was recently asked to give a 15-minute rapid update on changes in infectious diseases that would be of interest both generally and for an audience of family physicians at the CAFP Clinical Update in San Francisco.
The list of interesting items was long and I pared the brief discussion to a few items. The list:
- Antibiotics in severe sepsis
- Clostridium difficile
- HIV pre-exposure prophylaxis (PrEP)
- Moxifloxacin failure in short course TB
- Acute skin and skin structure infections (ASSSI)
- Carbapenem-resistant enterococcus
- Polyvalent pneumococcal vaccine
I have culled the following points from the long part of the short talk:
Antibiotics in sepsis – no comment as this wasn’t relevant to most PCPs.
Chikungunya – a mosquito-borne viral illness with over 6,600 cases in U.S. travelers to endemic areas of the Caribbean and even a few home grown cases in Florida – expect to see more in the southeastern U.S.
Dengue – getting close to a vaccine for this other mosquito-spread disease.
EV-D68 – this echovirus causes respiratory illness, particularly in the young with asthma, but it has now also been linked with a polio-like motor paralysis from which recovery is slow and/or incomplete.
Influenza – the vaccine was off-target this past influenza season. But we have learned that vaccination of a pregnant mother does extend protection to the newborn.
Measles – multistate outbreak linked to a source at Disneyland and spread among the unimmunized and in some cases the immunized. Perhaps Disneyland is not the Happiest Place on Earth for a while. 169 cases of measles reported to the CDC from January 1 to May 1, 2015, in 27 states. Wasn’t measles elimination in the US announced in 2000?
Microbiome – fascinating science about how the personal microbiome can affect individual health. Why are 80% of antibiotics used in animal husbandry? It has long been known that antibiotics cause animals to gain weight! Get that!
Moxifloxacin failure in 4 month treatment course of smear-positive TB in combination with other drugs compared to standard treatment regimens.
Carbapenem-resistant enterococcus – spread by endoscope with some fatal outcomes. Makes me sad to be a Bruin alum.
Pneumococcal conjugate vaccine – recommended for those needing pneumonia prophylaxis. Be aware of the separation and sequencing of this new vaccine and the older pneumococcal polysaccharide vaccine 23 (Pneumovax).
That leaves Ebola, HCV, C diff, PrEP, and ASSSI, which I will address in my next blog post.
Marshall Kubota, MD
When I mention America’s pastime, I’m not talking about baseball. If you still think baseball is America’s pastime, you’re revealing yourself as a Boomer or member of the Greatest Generation. According to Gallup Poll results on most loved sports, 1972 marks the point at Continue reading
“Lore: traditional knowledge or belief”
Let me say at the outset that by lore I mean information whose validity is not confirmed. Lore is a version of “truthiness,” as Stephen Colbert would say. Most physicians are familiar with the concept of “chart lore.” Chart lore is information that somehow found its Continue reading
Running marathons has become a very popular activity in our country with over 540,000 people completing the 26.2 mile distance in 2013. The demographics of marathon runners have changed significantly over the past few decades. Whereas 90% of the 143,000 Continue reading
All prescribers are certainly aware of (and hopefully accept the reality of) increasing antibiotic resistance. While guidelines continue to be released encouraging less antibiotic use for sinusitis, bronchitis, and otitis media, there also continues to be use or, more Continue reading