Infectious Disease

Abdominal Aortic Aneurysm Disease: The Silent Killer

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Posted By SHL Librarian

Presented by: Ronald L. Dalman, M.D.
Professor of Surgery
Stanford University Medical Center
September 26, 2007

Lecture Overview:
There has been considerable interest recently in public education and screening for Abdominal Aortic Aneurysm (AAA) after a front page Wall Street Journal article about it received the Pulitzer Prize for Health Reporting a few years ago. There are 30,000 deaths in the US each year related to AAA, a condition that years ago claimed the life of Albert Einstein and George C. Scott. AAA occurs when a portion of the aorta becomes worn out due to the loss of elastin, a protein that promotes tension in the skin and blood vessels. The cause of an aneurysm can be genetic but smoking is the single highest risk factor in causing AAA. Dr. Dalman provided a thorough overview of the definition and clinical management for small and large AAA. While there is no clear and well-proven treatment for small AAAs (between 3 and 5.5 cm), there are surgical options for the larger, more worrisome kind of aneurysm (5.5 cm or larger).

Who?

  • AAA is among the top 15 leading causes of death in mature adults
  • 6% of men
  • 1.5 % of women

What and Where?

  • An Abdominal Aortic Aneurysm (AAA) is an enlargement of the aorta. The aorta, which starts in the heart and moves through the left side of the chest, through the diaphragm and into the abdomen, is the largest artery in the body and supplies blood to the entire body.
  • An AAA occurs in the space between the lowest part of the sternum (the blood supply to the kidneys and other organs) and the part of the aorta where it splits into the iliac arteries (supplying blood to the legs).
  • According to Dr. Dalman, there are usually six years between the identification of a 3 cm AAA and the recommendation for surgery.
  • The most common symptom is pain, often confused with back pain.
  • The growth rate is about .4 cm annually, which translates to about two and a half years for an AAA to grow a centimeter.

There are two types of surgeries to treat AAA:

  1. Abdominal aortic aneurysm open repair
    A large incision is made in the abdomen to directly visualize the abdominal aorta and repair the aneurysm. A cylinder-like tube called a graft may be used to repair the aneurysm. Grafts are made of various materials such as Dacron (textile polyester synthetic graft) or polytetrafluoroethylene (PTFE, non-textile synthetic graft). This graft is sewn to the aorta, connecting one end of the aorta at the site of the aneurysm to the other end. The open repair is considered the surgical standard for an abdominal aortic aneurysm repair.
  2. Endovascular aneurysm repair (EVAR)
    EVAR is a procedure that requires only small incisions in the groin along with the use of x-ray guidance and specially-designed instruments to repair the aneurysm. With the use of special endovascular instruments and x-ray images for guidance, a stent-graft is inserted via the femoral artery and advanced up into the aorta to the site of the aneurysm. A stent-graft is a long cylinder-like tube made of thin metal mesh framework (stent), while the graft is made of various materials such as Dacron or polytetrafluoroethylene (PTFE). The graft material may cover the stent. The stent helps to hold the graft open and in place.
    For patient education information and additional information on surgical repair, please visit:
    http://www.vascularweb.org/

When?
AAAs that require treatment are most likely to occur in people over 55. Often an AAA is identified when a patient is screened with ultrasound or CT scan for another condition. People with a family history and with symptoms may be screened at any time depending on a doctor’s recommendation.

Why?
The highest risk factor for AAA is smoking (a risk of 5 on a scale of 1-5) and genetics (a risk of 1.5)

For More Information:

Stanford Health Library can do the searching for you. Send us your medical questions.

Division of Vascular Surgery at Stanford University
http://vascular.stanford.edu/
The Division of Vascular Surgery at Stanford aims to provide a model of clinical and scientific excellence in the diagnosis and treatment of vascular diseases, to deliver the highest quality of care to our patients by a team of dedicated surgeons and nurses, and to achieve these goals within an environment that fosters compassion and respects the humanity of the individual person.

Link to Clinical Trial information at Stanford Medical Center:
Abdominal Aortic Aneurysms: Simple Treatment or Prevention (AAA: STOP)
http://aaastop.stanford.edu/
If you are a patient with a small abdominal aortic aneurysm (<5.5 cm in size) and over the age of 50, you may qualify for participation in the AAA: STOP study. The goal of AAA: STOP is to gather information on AAA risk factors and determine whether an exercise program modifies the progression of AAA disease. Please contact Julie White at Stanford University for more information on this research program by phone at (650) 498-6039 or by email at [email protected].

Medicare AAA Screening Benefit
http://www.vascularweb.org/patients/medicarescreening/index.html
The Screening Abdominal Aortic Aneurysms Very Efficiently (SAAAVE) Act provides for a free, one-time AAA screening as part of the “Welcome to Medicare” physical exam.
Men and women with a family history of AAA and men who have smoked at least 100 cigarettes during their life qualify for the Medicare screening.

Dr. Dalman’s Stanford Profile:
http://med.stanford.edu/profiles/Ronald_Dalman/

Travel Medicine: What You Should Know Before You Go

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Posted By SHL Librarian

Presented by: Brian Blackburn, MD
Assistant Professor, Medicine – Infectious Diseases
Stanford University Medical Center
May 10, 2012

Watch the video

Getting sick is not usually on the itinerary when planning a trip. Unfortunately though, travelers can be exposed to a wide array of diseases that are uncommon at home that can wreak havoc on even the best-laid vacation plans. International visitors often forget that exotic destinations can be dangerous and can put themselves in jeopardy if they don’t prepare for potential health problems.

As international and adventure excursions increase in popularity, physicians are recognizing the importance of understanding the special medical needs of travelers, overseas workers, and adventurers. It’s estimated that more than 760 million people will cross international borders this year and that number is expected to grow, according to Brian Blackburn, MD, a clinical assistant professor of infectious diseases and director of Stanford’s new Tropical Medicine and Travelers Health Clinic, who spoke at a presentation sponsored by the Stanford Health Library.

Despite the escalating number of people leaving for foreign lands, only 35 to 60 percent seek any medical advice before leaving home, and only 10 to 20 percent visit a travel health clinic, he said. But between 25 percent and 65 percent report some sort of health problem while overseas or after returning home.

People visiting friends or relatives (VFR travelers) take travel health precautions even less often but tend to report getting sick more and require more hospitalizations. VFR travelers often consider themselves to be at little risk because they are simply “going home” or because they consider themselves immune since they were exposed when young. “These people are actually at higher risk, so they should see a physician before a visit overseas,” he added.

The numbers back him up: Only 9 percent of tourist travelers to Africa who developed a fever had malaria, compared to 45 percent of VFR travelers. And more than 90 percent of all travelers report taking a risk by not following appropriate health precautions regarding eating and drinking.

“Much of travel health involves using common sense and being safe,” said Dr. Blackburn. “Avoid insects by using bed nets, proper clothing, and repellents with DEET. Be safe with food and water. Don’t swim in fresh water in certain areas. Drive carefully: Traffic accidents are the most common problem abroad—more than infectious diseases.”

Malaria
Malaria is the most deadly parasitic disease in the world, said Dr. Blackburn, causing nearly 1 million deaths a year worldwide. Usually transmitted by a type of night-biting mosquito, malaria can be fatal in a matter of days. It causes fever and flulike symptoms, which usually take between a week and month to manifest. It’s most common in sub-Saharan Africa, Oceania, Asia, and South and Central America.

There are several effective medications available that can prevent malaria. All involve taking the drug before, during, and after travel to an area with malaria. The choice of drug depends on the travel destination and resistance patterns of malaria in that area, so talk to a physician about your itinerary to determine the most appropriate medication.

These chemophrophylaxis drugs include malarone, chloroquine, mefloquine, doxycycline, and primaquine, which vary in terms of cost, treatment regimen, and possible side effects.

Immunizations
International travelers should be up to date on vaccinations for measles and mumps, influenza, and hepatitis B. Most U.S. residents are immune to polio, but a one-time booster shot is recommended for adults going to certain countries in Africa and Asia.

Hepatitis A is now a routine childhood immunization, and requires two doses over six months although most people develop good immunity after the first dose.

A type of bacterial meningitis can be rapidly fatal, even with antibiotics. Immunization is recommended for travelers to certain countries in Africa and the Middle East. Re-vaccination is required every five years for those at continued or renewed risk.

Japanese encephalitis, a viral disease endemic to much of East, South, and Southeast Asia, is spread by mosquitoes in the (summer and fall. Despite its rarity for travelers, about one-third of people who show symptoms die from the disease. Long-term travelers to these areas or those spending time in rural sites should be vaccinated.

Rabies immunization is optional for most travelers since the disease is not common and vaccinations are expensive. However, for high-risk travelers, such as wildlife workers, veterinarians, or people expecting prolonged stays or rural exposure where medical facilities may be unavailable, a rabies shot may be a good idea. “Rabies is nearly 100 percent fatal. There’s essentially no treatment, so the only approach is to prevent it,” said Dr. Blackburn. With any bite, it is very important to clean the wound thoroughly, and seek medical attention immediately.

Some countries require proof of immunization against yellow fever for entry. Common in tropical areas of Africa and South America, this viral disease is spread by mosquitoes and is fatal in 20-50 percent of those infected. The risk of exposure is about 10 times higher in Africa than in South America.

With no cure available, vaccination is the most important measure against yellow fever. Re-vaccination is required every 10 years and needs to be done at least 10 days before departure. About 10 to 30 percent get a mild reaction to the vaccine, which can range from flulike symptoms to headache. Infants, pregnant women, people with a thymus condition, and immunocompromised patients should not get the vaccine, and the risks of the vaccine are also higher in people over age 60, said Dr. Blackburn.

Travelers to most of the developing world should receive the typhoid vaccine. Typhoid is a bacterium acquired by consuming contaminated water or food, and causes fever, abdominal pain, and other symptoms. The injectable vaccine is given as a single shot that lasts about two years; the live vaccine requires four oral doses over eight days and lasts about five years.

Travelers’ Diarrhea
Even the most experienced globetrotters, using all recommended food and water preparation precautions, can suffer bouts of travelers’ diarrhea. The most common ailment affecting overseas visitors, diarrhea is caused by bacteria (80-90 percent), viral infections (5-10 percent), or parasites (less than 10 percent). High-risk areas include most of Asia, the Middle East, Africa, Mexico, and Central and South America. Daily doses of Pepto-Bismol can decrease the possibility of acquiring diarrhea, although this is not routinely recommended. A course of antibiotics can treat rather than prevent the condition.

About the Speaker
Brian Blackburn, MD, is a clinical assistant professor of infectious diseases and the director of Stanford’s Tropical Medicine and Travelers’ Health Clinic. He received his MD from Chicago Medical School and did his internship, residency, and fellowship at Stanford. His research and clinical work has brought him to Liberia, Nigeria, Kenya, India, and Bangladesh. He is certified by the American Society of Tropical Medicine and Hygiene in tropical medicine and travelers’ health and by the American Board of Internal Medicine in infectious diseases and internal medicine.

About the Clinic
Stanford’s Tropical Medicine and Travelers’ Health Clinic was established to provide consultation and treatment for visitors abroad. It is located at:
900 Blake Wilbur Drive
Second Floor
Palo Alto, CA 94034
650-736-5700

For More Information:

Stanford Health Library can do the searching for you. Send us your medical questions.

About Dr. Blackburn
http://stanfordhospital.org/profiles/Brian_Blackburn/

Stanford Tropical Medicine and Travelers’ Health Clinic
http://stanfordhospital.org/clinicsmedServices/clinics/travelmedicine/

Division of Infectious Diseases and Geographic Medicine
http://med.stanford.edu/id

Centers for Disease Control / Travel
http://wwwnc.cdc.gov/travel

CDC Yellow Book (Guide for Travelers)
http://wwwnc.cdc.gov/travel/yellowbook/2012/table-of-contents.htm