An accurate diagnosis is essential for successful treatment. However, as information about a person’s medical condition is gathered, the risk and cost of obtaining the information must be considered. Often, we (the patient and Physician) make decisions with an incomplete set of data. This is where the art and science of practicing medicine meet.
Arriving at a diagnosis begins with the history and physical exam. Physicians are trained to follow a specific pattern. The history begins with a chief complaint and includes the subjective (your story), allergies, medications, prior operations, chronic medical conditions, a family history, a social history including exposures and habits, and finally a review of systems. Help and protect yourself by bringing a list of your allergies, current medications, and prior surgeries. With chronic or serious conditions, it is helpful to keep a copy of your medical records.
I love computers, but I am skeptical that they are going to solve our medical information problem. The government’s plan is to gather all of our personal records in a massive computer system and then pass laws to protect our privacy. One of my favorite dreams is being born in a very technical, computer driven society, and then inventing the pencil and paper. Expensive equipment, hard drive failures, blackouts were no longer a threat to the information. Are you willing to keep your favorite picture on a computer? Keep you own health care records.
Medical logic is applied as we begin gathering the information. After you complete your initial story, the information guides the following questions. We look for a pattern that fits a specific diagnosis and then ask additional questions about that condition. Sometimes we have to back-track, reconsider other possibilities and ask new questions. This process continues until we arrive at a working diagnosis.
Occasionally the patterns are unclear, or the symptoms require us to do additional tests just to exclude serious possibilities. These evaluations can be frustrating, because at the end, I can only reassure the person that they do not have a serious diagnosis.
Disease evolution has an effect on diagnosis. At the beginning of an illness, there are only a few subtle clues, but as time progresses, more symptoms develop and guide the process. These new clue are very valuable in arriving at a diagnosis of a difficult illness. This creates a paradox; it is more difficult to diagnosis an illness early, when it is easiest to treat.
There are a few illnesses that evade diagnosis with an average time from onset to diagnosis of three years. This category includes adrenal insufficiency, multiple sclerosis, pulmonary hypertension, normal pressure hydrocephalous, etc.
And finally, we monitor the response to treatment. This can be misleading, but a failure to respond would trigger a reevaluation.