The medical gaze
Credit: National Cancer Institute, USA, via Unsplash
Modern medicine was born out of the Age of Enlightenment. As Michel Foucault describes in, “The Birth of the clinic,” the teaching hospital (Salpêtrière in Paris) transformed medicine from a religious treatise to a discipline focused on intellectual empiricism and rationalism. Through medical gaze (direct observation), doctors developed epistemes (disease scripts) through which they could classify disease.
Throughout the succeeding two centuries, Medicine thrived through empirical knowledge to diagnose disease. Much like the science of phylogeny that classified the natural world, the disease script has enabled doctors to classify disease. It is these key characteristics that help us differentiate one disease from the other. Our knowledge of medicine comes from being on the shoulders of giants like Jean Martin Charcot and Joseph Babinski who painstakingly described disease as they observed it from their patients over years in the hospital.
Take for instance a patient I saw a few months ago with the residents. She presented to the Emergency Room with fever, sore throat, and enlarged lymph nodes in her neck. In the Emergency Room, the screening test for Mononucleosis (Monospot test) was negative and CT scan of the neck revealed many enlarged lymph nodes. When we saw her in the clinic as follow-up to the Emergency Room, we were a bit baffled by her presentation. Could a separate infection be causing her condition? Might she have something more sinister like a systemic inflammatory disease, or cancer of the lymph nodes? She was supposed to travel to Japan in a few days and was wondering if it was still safe for her to travel. Lucky for us, there were two key characteristics of the case that helped us arrive at the correct diagnosis.
On her physical exam, we noted that her spleen was enlarged. The examination of the spleen is challenging and very few doctors agree with its proper examination technique[1]. In my exam, I perform two techniques. First, I feel the edges of the spleen with my hands (palpate) and, second, tap with a reflex hammer (percuss) on the lower edge of the left lung to listen for dullness below the 6th and 7th ribs (Traube’s space[2]) . She had both findings on exam. As Mononucleosis invades the body, it causes the spleen to enlarge. This is why we always tell children to refrain from contact sports when they have Mono. As the spleen enlarges it is no longer protected by the rib cage and is easily exposed to bruising or rupture.
The other key characteristic was the shape of her blood cells. Lymph cells (lymphocytes) tend to look like big blue dots. This is because, as the brainiest of blood cells, they have a big nucleus to help them remember all the foreign substances (antigens) that circulate around our bodies. When these cells are infected with the Ebstein Barr virus (EBV/mono) they tend to shape shift into cells that resemble Ballerina skirts. The blood test mentioned that she had such cells (atypical lymphocytes) in her blood. I would have overlooked this key characteristic had I not had a conversation with our Chief Resident on this concept the week prior.
Now instead of 3 data points (fever, enlarged lymph nodes, and sore throat) I had 5 data points to arrive at our diagnosis (atypical lymphocytes, enlarged spleen). If we consider all independent observations, we will go from 87% certainty to 97% certainty that she has mono. Subsequently, a more sensitive blood test (EBV capsid IgM) confirmed that she had mono. With all the technological advances in medicine including diagnostic imaging and laboratory analysis, it is reassuring that the age-old skill of observation is still critical to our knowledge of medicine. This act being handed down from generation to generation of doctors beginning with Charcot at Salpêtrière just a few years after the French Revolution.