Dr. Rensimer’s Personal Statement: Cognitive Medicine/Diagnosticians

Posted on Sep 19, 2018 in Blog | No Comments
Dr. Rensimer in his 4th year of medical school at Temple University, 1975

Dr. Rensimer in his 3rd year of medical school at Temple University, 1974


I have often been asked, “Infectious Diseases, how do you get to a career like that? What brought you to it?”  Over the years I have reflected on this and the answer is both personal and, I think, an interesting story on how one, by following their passions and inclinations, can end up in a career that was unforeseeable.

Sitting on my bed in our Southwest Philadelphia row-home, a “blue-collar”, working neighborhood, I distinctly recall looking at a medical careers brochure I had picked up at a career fair that afternoon at Central High School.  At 16 years-old I had no idea what the medical field was about.  No doubt that the loss of a close cousin at 5yrs-old to staphylococcal pneumonia and a vivacious aunt at 16 yrs-old to meningococcal meningitis (both treatable bacterial infections) suggested a biological injustice that begged understanding. We were a lower middle-class, blue-collar,  working family and no one had even graduated college in our generation or that preceding.  I was interested in most things, both the liberal arts and the sciences.  In junior high and high school, my outside school passions were astronomy, archaeology, paleontology, and history (especially ancient history).  You could say that everything that fascinated me were hypotheticals – – things that could not be touched; things that are objects of speculation. You cannot touch a star or another planet. History is past, Likewise dinosaurs. Certainly, that was a lead in to my current daily preoccupations with microscopical and submicroscopical things–cells, molecules (medicines), and microbes. To function in my job, you must first “believe” this universe of the miniscule even exists. You cannot directly see or touch most of it. There is a leap of faith in the science and application of it.

But, on that seminal afternoon, my mind raced at the prospect of thinking like a doctor.  How did a physician enter the room of a sick or injured individual and ask the right questions about the person and their problems such that upon exiting the room he/she had built a list of possible explanations and an action plan to relieve suffering while reversing the physical damage?  Training to synthesize knowledge in chemistry, anatomy, systemic physiology of tissues, organ functions, disease, pharmacology (drug science), and much, much more, into a coherent hypothesis on the patient that brought them to the best outcome (even saving a life) was more than enthralling.  It was miraculous.  It was magic. I could think of no greater nor more worthy challenge.  And, on a personal level, immersion in these matters even allowed proximity to the mysteries of life and death.  It would not be just a job, but a personal journey to places unavailable to most people.  To the essence of the human experience, life itself. “Sign me up.”


So, despite no family precedent or healthcare relationships to draw on for career advancement leverage, I found myself in medical school, at Temple University in my hometown, Philadelphia, PA. It was far more than I had imagined back in high school.  And the field was so broad that it was a daunting challenge to know which direction to take at the multiple crossroads that kept arising. I had no mentor, no role model.  I had to reach into my basic psyche, to my heart and soul, to make my choices.  With the aforementioned avocations in my younger years, I soon realized that the more mechanical fields, the surgical specialties, were not where I belonged. No, I was a conceptualist, devoted to the essential value of “cognition.” And, I did not want to devote my life to one organ, like the heart or brain. I wanted to stay capable of understanding all the tissues and organs and their interplay, in health and illness. I did not want to confine myself to dealing with diseases and problems of only the very elderly. I did not want to be mostly taking care of one sex or the other. Finally, I wanted to handle difficult, complex, refractory diagnostic problems and high-stakes cases. So, I headed to Internal Medicine residency at Northwestern University in Chicago, IL, the province of the cognitive elite in medicine.

One day, during “morning report” presentation of cases, our Chief of Medicine, James H. Webster, MD, dropped in to observe our performance. After listening to some well-intentioned social commentary by one of the residents (training physician) presenting one of his cases, strong on emotional and social “soft aspects” of the case, Dr. Webster interjected that we were not their family, their friend, or their pastor. He said we were so much more. We were their physicians. He said only we can offer them what none of the others can and that that’s our place and purpose – a timely, accurate diagnosis and the least risky, most effective plan of care to manage and/or resolve their medical problem(s). Do that and only then concern yourself with things in your relationship with the patient that they can easily get from others. The take away? Your position is unique and vital. Stay focused on that. I knew I had made the right choice. I was home.

Infectious Diseases (ID), as a subspecialty of the Internal Medicine specialty, did not exist as a board-certifiable field until I was about to graduate medical school in 1975. So, it arrived just in time to fit all my personal attributes. And, because the field was not organ-specific, the ID people were the closest thing to the ultimate internal medicine diagnosticians. That brought me full-circle back to what I was dreaming of as I read the career brochure as a teenager years before. For mastering medical “thinking”, ID was ground zero. And that was ID fellowship at University of Texas, Houston.


Think about the variety of infectious agents: viruses, bacteria, parasites, and others. Within each of those categories are innumerable variations. The ID specialist, in addition to first passing the board certification exam in Internal Medicine (covering the knowledge base in cardiology, pulmonary, gastroenterology, nephrology, neurology, endocrinology, hematology, dermatology, immunology, rheumatology, oncology, allergy, etc.), must then pass the analogous ID board exam.

ID disease states are myriad, usually categorized by organ, organ system, disease process/mechanism, and type of infecting agent,

  • Bloodstream infection
  • Bone/Joint infection
  • Endocarditis (heart valve infection)
  • Hepatitis
  • Intestinal infection
  • Meningitis/encephalitis (nervous system)
  • Pneumonia
  • Soft tissue infection
  • Urinary tract infection
  • Etc. (many, many more)

For each of the above categories, there are dozens of different types of infectious organisms (or agents) diseases—for example pneumonias: pneumococcal, viral, Hemophilus, Legionella, Mycoplasma, staphylococcal, influenza, Klebsiella, aspiration, TB, fungal, etc. Sometimes ID entities are more characterized by the infectious agents themselves causing unique  patterns of organ involvement,



Hepatitis C

Lyme disease

Etc. (many, many more)

Finally, all of the above is placed, by the ID specialist, into the biological context – the individual host organism,

Male / Female

Young / Old

Medical pre-conditions (relevant to infection),


Liver/Kidney Disease


Physical Trauma/Injury

Chronic Lung Disease


Social conditions,

Nursing Home Resident

Recent Travel

Insect/Animal Exposure

Sexual Activity/Behaviors

Substance Abuse

Recent Illness Contacts

And, for each infectious agent (hundreds), the ID specialist must know, or be familiar with, the laboratory microscopic staining appearance and culture characteristics that identify the agent; the molecular mechanisms of the disease, including the characteristic response of the host’s immune system to the agent; the usual array of organs and tissues involved by the disease (as well as atypical presentations); the infectious agent’s means of transmissibility to others; the usual clinical course of illness, including incubation from time of exposure; the time course of the disease and its possible complications; the early and late disease state symptom patterns; the risk of organ damage and death; the laboratory and imaging test findings with the disease; the first-line and alternative treatments; dosing and route of administration changes in treatment medication in the face of liver or kidney function decline during disease; public health prevention strategies to mitigate spread to others and throughout the community.

Each infecting agent has a “tropism”: anatomical sites or organ systems they target. Rabies and West Nile viruses to the brain. Staphylococcal germs to soft tissues and wounds. Salmonella to the intestines and liver. Influenza viruses and pneumococcal bacteria to the respiratory passages and lungs. HIV to the immune system. Malaria parasites to red blood cells.

And each organism differs in virulence (tissue destructive and invasive capacity) and pathogenesis (mechanism of disease production) – the ability to invoke a destructive inflammatory response from the host and to spread through specific body pathways: the soft tissues, circulatory system, lymphatic system, organs. Some organisms cause disease slowly (TB, HIV, hepatitis C, syphilis). Others are rapidly destructive (Ebola virus, plague, bacteremia). Some infections are self-limited, and so resolve after the acute illness without specific treatment (mononucleosis). Others persist for years in biological reservoirs (HIV, hepatitis C). Some readily spread person-to-person (measles), others not. Some infectious agents most often exploit weakened immune systems (opportunists) – Cryptosporidia, Pneumocystis, Strongyloides. And, some come from animals – rabies, toxoplasmosis, leptospirosis, tularemia, psittacosis, brucellosis. Others from insects: mosquitoes (dengue fever, malaria, West Nile Virus, Zika Virus), “kissing” bugs (Chaga’s disease), and ticks (Rocky Mountain Spotted Fever, Lyme disease, babesiosis). So, there are the biological vectors (animals, mosquitoes, ticks, etc.) of an agent, the social context of the patient (nursing home, hospital-acquired, sexually polygamous, post-travel, post-trauma/surgery, immune-suppressed, etc.). There are the times of the year to consider (seasonal illness like influenza and West Nile virus). There are the communicable diseases’ patterns and activities at play currently in the local and national community to factor (epidemiology) analyzing the patient sitting before you—foodborne illness, contaminated waterborne disease, influenza, and West Nile virus outbreaks.

As previously stated, the ID specialist must first train in and pass board examinations in Internal Medicine. Why is that relevant? Because many disease states are inflammatory to the body, yet are not infection-based. Gout, autoimmune diseases (lupus, rheumatoid arthritis), allergic reactions, some malignancies are a few examples. Many medications can even cause fever and physical and lab/imaging abnormalities that mimic infections. Fever of unknown origin is worth reading about; in my mind the ultimate diagnostic challenge in medicine and reward for becoming expert in this field.

Faced with an unexplained fever; elevated white blood cell count; inflammatory appearances on a chest x-ray; or a swollen, red, tender limb, the first consideration is to rule out an acute infectious process that may put the patient at risk without prompt, correct treatment. But, the ID doc must also consider non-infectious causes of the problem (broader Internal Medicine) that may actually be at work and which require entirely different treatment approaches than anti-infective (antibiotics, antivirals) medications, such as potent anti-inflammatory, immune-suppressant agents, like steroids (contraindicated in most major infections). ID is a multi-organ, multi-system subspecialty that, more than any other, requires the physician to be at the top of his/her foundational game in Internal Medicine.

I think you are now getting the challenge of all this – a challenge that goes on with every case, every day, over decades of experience, unrelenting and never tiresome.


There is the decision to treat…or not. If no tests have revealed a specific invader accounting for the illness or problem (usually fever), do you start an antibiotic (and possibly diminish the yield of future testing, and so a specific diagnosis, with a more refined treatment option and then a less risky side-effect downside and with a better chance of cure), or do you watch? Perhaps it’s not a bacterial process and so antibiotic treatment gives false security and complacency, and then the patient declines on the wrong treatment. More damage is done as the disease progresses unchecked and time is lost. Perhaps it’s not even an infection – instead, one of myriad other inflammatory diseases tormenting your patient, though the clinical presentation has all the hallmarks of infection. You may be treating for infection and encountering ill-effects of futile infection directed drugs that add confusion on whether the new problems are part of the original illness or caused by your treatment, again, while the disease process carries on and critical time is lost and possible damage incurred.

If an antibiotic is chosen, which one out of dozens? Will the antibiotic penetrate the body compartment or tissues where the invader resides (nervous system, heart valves, lung tissue)? Will the antibiotic’s activity against the agent be diminished by low pH (highly acidic environment) in an infected collection, like an abscess? Will the antibiotic penetrate cells, as needed for intracellular (inside the cells) pathogens, such as Salmonella, Brucella, Legionella? Is a life-critical bactericidal (killer) agent needed, as in heart valve infections, or will a static agent (suppressive against the invader) be sufficient? Are combinations of antibiotics needed to minimize drug resistance development to any single one antibiotic class(and eventually all drug options), such as anatomical reservoir infections (lungs in cystic fibrosis) or slowly killed infections (because the infectious agent divides, and so takes up anti-infective medicinal poisons, very slowly), such as tuberculosis, HIV, and hepatitis C? Using a single antibiotic in these situations could eventually kill your patient (because of drug resistance development by infectious agent mutation that should have been foreseen as possible by the treating physician).

How is the dosing of the anti-infective agent adjusted (if at all) according to the body individual patient’s metabolism in the face of decreased kidney or liver function or extremes of body size? Are the potential toxic effects of the antibiotic choices acceptable, given the inherent risks of the infection itself? Do you use a strongly toxic drug for an infection that is causing dramatic symptoms, but with remote potential for death or enduring damage? In a word, is the treatment worse than the disease? How do you make a risk-benefit choice of a treatment proportionate to the threat of the disease process and the patient’s condition (which may be frail and tenuous)? Do you substantially harm or kill the patient on the way to killing the infecting agent? At what point in the clinical course of a very ill patient can you justify waiting to use a drug with great toxic potential that could tip the scale toward instability and death… or survival; or, have death as the end result because of reticent indecision to make a bold move? This happens every day.

Once started, how long must you wait to decide whether the course you have taken is the right one or is failing; and what physical and lab indicators are to be watched? The answer to this varies for each specific type of infection.  For a particular infection and its severity and extent/location in a specific case, when do you judge failure (and make a correction in approach)? Do you take into account that some abnormalities, such as the “infiltrates” of pneumonia in the lungs on chest X-ray, may lag in improvement behind fever, white blood cell count, etc.? Changing a course of treatment prematurely because you do not know how to “value” a particular test abnormality at the point where you are in the treatment and disease process may lead to abandoning a proper treatment, resulting in prolonged recovery (and complications) or relapse. When do you advise an invasive diagnostic or therapeutic procedure (bronchoscopy, liver biopsy, abdominal surgery, amputation) as necessary, albeit risky? This is called clinical decision-making and it is both a talent and developed skill, artfully practiced as a byproduct of experience and information mastery and wisdom. Few physicians ever have enough very complex, high-risk cases on an ongoing basis over their entire career (with them mostly calling the shots alone) such that they can achieve that skill.

Finally, all these facts must be refracted through the context of the actual individual who is the victim of the disease. Whether they have had a history of strokes or heart disease. Whether they have inadequate arterial perfusion of (and so delivery of medicines into) the infected limb from their diabetes. Whether they have had lung damage from recurrent pneumonia. Whether they have immune weakness from HIV or immune-suppressant medications. Whether there are possibly infected prosthetic hardware or intravascular devices. Whether there is damaged or dead tissue, impenetrable by antibiotics. All these, and many more issues specific to each medical case, have great impact on the approach and the achievable outcome, as well as the timing and aggressiveness of the plan of attack. Consider all of this and you have the most superficial appreciation and understanding of what must be thought of and acted upon with  each diagnosis: the least expensive, least risky, best tolerated, and most effective treatment approach leading to the lowest morbidity (damage) and mortality (death) of those entrusted to you as expert. And this must be re-evaluated daily during a very active, progressive illness. And, if you are successful in practice, you are loaded down with these types of cases everyday.


There is more, but this is the environment of ID decision-making and cognitive process that is achieved after 4 years of medical school, 3 years of Internal Medicine training, and 2 years of ID fellowship, and then many, many cases, building knowledge and wisdom from training and experience. This was the world I was looking for at 16 years-old –- I just didn’t know it or where I’d find it.

The patient’s picture is constructed, and the timing and types of tests and interventions are ordered based on the risks of those actions versus the risk of not doing the right thing timely, since infections are dynamic processes which can damage or kill if not controlled. The clock is ticking and an invader is in the fortress – it is a hunt and destroy mission, requiring precise timing and selection of weapons to minimize harm to the host (patient) who may be very fragile. It is not dissimilar to the video games to which many young people are addicted, except that substandard performance can mean lifelong damage or the loss of a spouse, a parent, a child; a trip to the graveyard.

All of the training allows, in minutes to hours, the creation of a plan that balances all the risks/benefits of diagnostic testing and treatment interventions, specific to this unique patient and case. And, each subsequent day, over the course of illness, all of these issues are re-appraised and re-balanced. In practice, the ID specialist manages dozens of such cases each day. Everyday there are “incoming” – breaking emergencies that require a call to the bullpen. You are it. If you are capable, there is nothing like it. “Give me the ball to finish the game.” Another analogy is the symphonic conductor, leading all the players and sections of a symphonic orchestra, such that timing is precise and synchronized and culminates, climactically, right on time, to the best performance and outcome. And all of this is done in the most tense emotional circumstances with families standing close by, putting their faith in you.

The TV show “House” gave the public an intense, inside look, with some entertainment hyperbole, at the drama and challenge of investigative, cognitive medicine. Prior to Dr. Gregory House, almost all medical shows offered surgery and emergency medicine as the sexy, white-hot arenas of the profession. “House” showed the minds of physicians digging through the complexity of tangled, time-critical, clinical problems while the clocked ticked off tense minutes to impending patient damage or demise. After over 100,000 cases, I still think collecting information into a theory (called a “diagnosis”) and then ordering a medicine that looks like colored water to be infused IV, with a resulting drop in fever and stabilization of blood pressure and multi-system organ recovery is as close to magic as we have in the real world.


After these decades following my 1975 medical school graduation, the wonder of what I get to do every day is as remarkable as when I saw my first case. I am still fired up when the call comes at 3AM because I am needed for a critical decision in a breaking situation. And teasing out the nuances of a meticulous medical history( the patient’s story) and from an exacting physical examination still are the defining skills that solve most difficult cases rather than diagnostic laboratory and imaging tests. At Temple University School of Medicine, in our first course in “Physical Diagnosis”, where we were taught all the detailed specific questions and the strategy of goal-directed patient interviewing, it was emphasized over and over that a careful history done by an highly skilled physician’s mind would yield the likely diagnosis over 95% of the time. That has stood the test of time over these over 45 years. It is as true today. And, it always will be.

I am in love with the notion of a master diagnostician — someone who discovers the “hidden” facts (“between the lines”) and then arranges them and the more obvious information from chaos into order and relationships, and discerns the subtle and seemingly inconsequential toward a sublime solution. And, most often, this is an intellectually ethereal process involving cells, molecules, infectious agents which cannot be seen or touched without a microscopic or at all, but, believed in and mastered, culminating in diminished misery and saved lives. Is there anything more noble or exciting or incomprehensible?

Giving it thought, at 73 yrs-old, I am exactly where I should be. There is no other medical specialty I would consider. Would I like to have been anything else? Of course, when I hear Andrea Bocelli sing, “The Prayer” before a packed house, I think, “Wouldn’t it be wonderful to do that, to create something of ineffable, singular beauty, taking others to a higher place…wow, I would love to do that.” And there are other examples of extraordinary talents and creations that each of us might find ourselves musing, “I wish that were me.” Would that we had more than one life, because such existential experiences are earned through decades of incessant training and practice. There is no easy path to this end. As I have described, what I have done is just that. So, I cannot diminish it by ingratitude—that saving limbs and lives, allaying suffering, and returning people to what is important to them in their lives—that what I, as a physician, do is less than those other special lives envied. I am invited into unforgettable moments in people’s lives when the reality is chilling and inescapable—not a fiction or a melodrama. I am entrusted with lives by loved ones.

Yes, this narrative is both expository about what a physician is, and more specifically my personal quest to be a diagnostician as a self-defined professional goal. But, beyond a technical essay, I must conclude stating that all of this distills down to being “a healer.” I am most proud of that. I sincerely, long past the trials of getting here and all life’s cynical pressures that might conspire to distort or demean the original expectations of a naive young boy from South Philadelphia, still believe in the superceding nobility of the healer among humanity’s archetypal roles.

The message for the young? Get moving. Commit yourself to becoming a master at something in your life. Something that is not easy. Something that is hard, arduous and not easily duplicated. Something most will not do, cannot endure. “The road less traveled” cliche. Do not trivialize your life. You only get one. When you look in the mirror in your later years (I am approaching 74), you will smile. You will have something no one can take away from you. And, it will be an incomparable satisfaction. However, you need not, yet, think to know the end-point, the destination. Just get moving on a path that makes sense and that keeps inviting you to take the next step. The right direction, if you are honest with yourself and authentic, will open to you.

A wonderful quote from Charles Krauthammer, MD, political journalist and commentator, not long after he was diagnosed with terminal cancer and was saying farewell applies: “…I leave with the knowledge that I lived that life that I intended.” It cannot be said better.

Ed Rensimer, MD

Infectious Diseases

International Medicine Center

Houston, TX

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