In the 14th century, William of Occam stated, "Plurality must not be posited without necessity." This led to the concept populated by the famous internist, William Osler, who posited that each patient should have one disease, and that disease can explain all the patient's symptoms. In medical school, young physicians learn this philosophy and continue that philospophy throughout their medical career.
They often look for a single, unifying diagnosis in each patient and expect that all the patient's problems are related to this single diagnosis. When that diagnosis is treated with a standard treatment, the problems should go away. Dr. Friedman feels this philosophy of Occam's Blade is detrimental to modern medicine, especially endocrinology.
Patients are becoming increasingly complex and have multiple subtypes. It is important to distinguish between the subtypes, as that may alter treatment. Additionally, not all patients with a single disease present similarly. For example, patients with Cushing's syndrome may manifest diverse symptoms including weight gain, trouble sleeping, severe fatigue, decreased libido, high blood pressure, and diabetes, but most patients with Cushing's syndrome do not have all of these conditions and they only have a few of them.
Many physicians only know about Cushing’s syndrome from a picture of a severe Cushing’s syndrome they see in a textbook and may say to a patient that they don’t have Cushing's syndrome, because they lack one or more signs from that textbook case. Therefore, it is important not to lump everyone together with a diagnosis of Cushing's syndrome but rather to recognize that there may be different subtypes. This is especially important in the field of diabetes, which can be due to problems such as insulin resistance, lack of insulin production, inflammation, or problems with glucose disposal. Currently in diabetes, all patients are treated with similar medicines regarding of their etiology of diabetes. Dr. Friedman expects this to change in the near future, and subtyping patients will be come standard of care.