Author Archives: International Medicine Center

International Medicine Center Gallery

It’s Not too Late to Get your Flu Vaccine

Flu Season Continues


The proportion of deaths due to pneumonia and influenza (P&I) reported through the 122 Cities Mortality Reporting System is significantly elevated. This is the highest P&I in nearly a decade.

Antiviral treatment (Tamiflu/oseltamivir) of flu works best when started as soon as possible after symptoms develop. Antiviral drugs are prescription medicines that can shorten the duration of illness and lessen symptoms but, most importantly, they can reduce serious complications from flu infection, including hospitalization, intensive care unit (ICU) admissions, and deaths.

The Centers for Disease Control and Prevention routinely recommends vaccination as long as influenza viruses are circulating.

In addition to vaccination and antiviral drugs, everyday actions can help mitigate the risk of infection. Flu spreads mainly in droplets expelled when people with flu cough, sneeze, or talk. As always, stay away from people who are sick. If you are sick, stay home to avoid spreading your illness to others.

Influenza activity remains elevated in most of the country, although it may have peaked.

The first oseltamivir-resistant 2009 H1N1flu virus detected in the U.S. during the 2012-2013 influenza season has been reported. The majority of currently circulating influenza viruses are susceptible to the neuraminidase inhibitor antiviral medications, oseltamivir and zanamivir. Antiviral treatment with oseltamivir or zanamivir is recommended as early as possible for patients with confirmed or suspected influenza who have severe, complicated, or progressive illness; who require hospitalization; or who are at greater risk for serious influenza-related complications.

Conclusion:  Given the continued prevalence of influenza nationwide, the increased proportion of hospitalizable complications and death due to this year’s flu variety, and some indication of emerging resistance of some of the flu strains to the available flu medication (Tamiflu), it will be highly advisable for anyone not already vaccinated (or those vaccinated before October and at high-risk for flu complications, such as those 65 yrs and older) to be vaccinated or re-vaccinated in the next 4-8 weeks (depending upon the course of community-wide disease activity) in Houston.

Finally, close contacts (such as household members of active, documented flu cases) should be considered for treatment with a single daily preventive dose of Tamiflu until the ill person has recovered.

Edward R. Rensimer, MD
Director, IMC

International Medicine Center Gallery

What You should look for in a Travel Clinic

A travel medicine clinic should,

  1. Address both preventive and potential developing medical problems of travelers at risk from dangers inherent to their itinerary and trip activities as well as from pre-existing medical problems or age-related concerns.
  2. Expeditiously and expertly handle medical problems, particularly acquired infectious illnesses, that emerged during or after-travel.
  3. Maintain a full inventory of all U.S.-approved vaccines such that delaying or rescheduling an appointment never occurs due to vaccine or medication supply shortages.
  4. Optimally, have an on-site pharmacy to allow one-stop, comprehensive services.
  5. Provide all required immunization services for the most unusual travel exposures, but also the ability to provide targeted physical exams and the required documents for a variety of occupational assignments in health-hostile, remote areas.


A comprehensive, expert travel medicine organization (not a “shots” clinic) will have these features,

  1. Medical Director:  The clinic should have a “hands-on” director who oversees support staff, determines medical policies and procedures, and assures that the medical standards of care are the highest.Many travel medicine clinics are store-front franchises “directed” by semi-retired physicians who never practiced clinical medicine (radiologists, etc.), family practitioners (who took a weekend course in travel medicine), or an occupational medicine doctor (who has little or no experience with infectious diseases or other acute medical problems). Some “travel clinics” are directed by nurses or pharmacists with cursory training and no license to diagnose or treat. A legitimate director has training, experience, and certification in infectious diseases, tropical disease, general medicine (internal medicine, preferably), and travel medicine. Check on the qualifications of the director.
  2. On-Duty, Qualified Medical Specialty Physicians:
    The travel clinic should have on-site, available specialists who can expertly handle all pre- and post-travel medical issues, including ill patients and those with possible non-traditional problems not usually encountered in the U.S. medical care system (such as malaria, typhoid fever, dengue fever, etc.).Such problems are often time-critical, with potentially seriously damaging or fatal outcomes with delayed diagnosis or inexpert decision-making.Furthermore, a qualified specialist may often minimize medical costs because their comfort level with unorthodox situations is higher and they are less likely to reflexively hospitalize someone because they have returned from overseas with a fever – an action often triggered by the physician’s lack of confidence with the possibilities and true medical risks. Over-testing and over- or mistreatment would be quite possible.On-site physicians should handle the initial evaluation and ongoing management of patients’ medical problems at the travel clinic, only referring the travel patient for specific services outside his specialty qualifications.
TB Virus

The Dilemma of a Positive TB Test

Image Source: CDC/ Dr. Roger Feldman

You have been told by your doctor or your employer’s medical department that your tuberculosis (TB) test is positive. What does that mean? Do you have TB? Are co-workers and family at risk because they have been around you?  Should you be on medication? All of these questions are natural reactions to this report.

Tuberculosis is a serious infection, usually located in the lungs, but possibly anywhere in the body. However, it is also possible that the positive test is the result of underlying TB-like germs that do not have the disease-causing potential of Mycobacterium tuberculosis (MTb), the agent of TB disease. Active TB disease is the tissue-destructive interaction between the multiplying TB germ invaders and the host’s immune system. However, screening TB tests do NOT usually indicate disease.

About Screening TB Tests

TB tests can include the Mantoux and PPD skin tests, which are less used because they can be difficult to apply properly and even to interpret.

Now, doctors are using a relatively new blood test, Quantiferon TB IF (or T-Spot TB IF), which is an indirect immune system test for the presence of MTb, the agent of TB disease, as opposed to a direct culture or stain of tissues for the organism. In that regard, the Quantiferon TB (QTB) test is similar to the old TB skin tests.

These tests have been used in the past to screen high-risk populations – people who are likely to be or to have been exposed to others with active TB disease – to evaluate them for  the potential for active disease early on, before they become a public health risk for spreading TB, or to consider starting preventive treatment with isoniazid (INH) to kill any hibernating TB organisms before they have a chance to activate to cause disease.

So, it is possible for QTB to be positive when no disease or risk of TB transmission is present.

Context is an Important Factor in TB Risk

Another important point is made by the Bayesian Theorem of conditional probability. Simply stated, any test done and positive in the context of low probability for a disease is likely a false positive and not indicative of the disease or risk of disease.

For instance, if a 6-month old boy’s blood or urine were subjected by a laboratory mistake to a pregnancy test and were found to be positive, would it be reasonable to then conclude the 6-month old boy was pregnant?

If a QTB test were positive in a high-level U.S.-based executive who had never traveled outside the United States and had minimal exposure to sick people, is it likely to be a true positive for the TB organism? Perhaps if he had immigrant workers in his home and around him frequently. Otherwise, likely it is a false positive.

On the other hand, what about a Nigerian national sponsored by an international energy company who is training in the United States? A positive QTB here is much more likely to represent the presence of MTb, a true positive.

Because of the context-driven nature of the validity of any biological test, the U.S. Centers for Disease Control and Prevention has recommended QTB (and for that matter TB skin testing) not be done in low-risk populations, because the percentage of false positive tests will rise dramatically and lead to unnecessary anxiety and further medical actions, some costly and some with risk, and unlikely indicated or productive.

However, many companies with overseas operations have chosen to do the test as part of routine pre-work assignment or post-exposure medical screening protocols. In many cases, the QTB has replaced skin testing. The test is extremely sensitive, highly specific and bypasses the problems with skin testing, which, in addition to false positives and difficulty with reading a positive, requires expert placement and reading technique and several days for interpretation.

What do you do if you have a positive result on a TB test?

Deciding what to do with the result, especially in TB low-risk patients can be problematic. Many times, physicians will respond by placing a patient on INH prophylaxis. However, this medication can have side-effects such as peripheral neuropathy (nerve dysfunction), chemical hepatitis (liver inflammation, and rarely liver failure and/or death), and other reactions. Giving this medicine to prevent TB disease that may never happen is a complex risk-benefit decision analysis. It should never be an automatic reflex to a positive test.

First widely available for about 5 years, the QTB test has not been around long enough for the CDC or other public health agencies to correlate a positive QTB test in either TB low or high-risk populations with the likelihood of progression to disease. So, clinicians are somewhat on their own in considering a number of factors and the known science on them in creating a rational, reasonable response to a QTB positive.

IMC’s QTB Solution

At International Medicine Center, we have done just that. We have developed an analytical model for a responding to QTB positives based on current science. We are referred many QTB-positive patients, both from referring physicians and corporate clients. We review all the information on the specific case, and arrive at an action plan that makes sense and assures the patient that we will not miss active disease in them and that they will not be putting others at risk for TB. We are focused on not over-treating since most of the patients referred to us are truly low-risk for TB disease or activation.

Obviously, how to deal with a positive QTB will continue to be a work in progress. The complex issues of considering a positive QTB and responding to it, not too little and not to much, are truly expert functions to be handled by a qualified, experienced specialist.

Edward R. Rensimer, MD, FACP

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Tropical Medicine Consultation

I was referred to Dr. Rensimer in 2005 when I returned from Africa with a malady no doctor in our corporate system could identify. Dr. Rensimer did an evaluation and extensive testing that reduced the angst I had at the time. I was concerned that I had contracted an illness on one of my frequent trips to Africa as I often worked in the field where conditions were less than ideal.

His testing eliminated many of the high risk diseases I could have been exposed to in that environment. I came away from that initial contact with Dr. Rensimer completely satisfied and impressed with his professional demeanor and his absolute knowledge and control of his trade. I consider myself indeed fortunate that someone of his talent was available to those of us who are in a high risk and very vulnerable group.

I have been impressed with his personal commitment to me as an unknown referral patient, and I have chosen to have him as my primary care physician and intend to ask that my wife be included as one of his patients.

As a physician, I find Dr. Rensimer one of the most capable and dedicated professionals in his field. I find his performance to be exceptional and his behavior beyond reproach.

Bernard M.

Remote Location IMC Corporate Consulting

I have worked over 25 years in many locations around the world exploring for oil. Some of the areas are quite inhospitable, exposing one to a variety of diseases that can be quite lethal. I first met Dr. Rensimer when receiving my first international travel vaccinations, as he had been chosen to be our company doctor for international medicine.

While I was working overseas, Dr. Rensimer visited our field operations to conduct health evaluations, and presented his findings to our management and staff in London, England. He offered a great deal of insight, and contributed to our understanding of the health hazards and conditions that we faced in some very remote tropical locations. He gave us ideas and checklists that we have used for many years in our global operations, and there is no doubt, that he saved many of our employees from serious medical threats.

I have full confidence that Dr. Rensimer will do the right thing for me, as a patient, and as a person.

Mark C.