Chapter 4: Diagnostic process often reversed

Dr. Yeshwanth K. Amdekar, DCH, MD (Pediatrics), FIAP

We need proper balance in medical approach – Mark Twain Before you examine the body of a patient, be patient to hear his story, once you learn his story, you will also come to know his body – Suzy Kassem

Introduction

The process is nothing but a set of defined activities that have stood the test of time. It describes how a task should be performed and provides focus to make it better to ensure a successful outcome. The diagnostic process in medicine should follow the same principles. It is more important than a goal and the right process done in the right way leads to success.

Diagnostic process in medicine

The diagnostic process in medicine is complex but should follow the standard sequence. It should be a patient-centric activity of gathering information, information integration and interpretation (analysis of detailed history), complete and standard physical examination (with a focus on areas guided by history analysis) to form a working diagnosis. It is only after a provisional diagnosis is made that priority diagnostic testing is planned to confirm the final diagnosis. This is a process of diagnostic refinement followed by diagnostic verification. It brings in rationality, confidence, and consistency, enables planning, eliminates mistakes, improves outcome, avoids misuse of laboratory tests and drugs, saves time as well as cost and offers satisfaction to patients.

Detailed history analysis contributes to more than 80% of provisional diagnosis and thus enough time should be spent on gathering the right information. History is not his story; the patient focuses on what bothers him the most and not what the physician would want to know. History should follow the principle of “thought in action”. It means each question should be deliberate with a specific purpose, the answer to which should lead to the next relevant question. The thorough physical examination will further narrow down the differential diagnosis inferred from the analysis of detailed history. There exist increasing options for diagnostic testing, from which appropriate tests should be selected based on the provisional diagnosis. Epidemiology of common diseases should guide the priority of tests.

Reversed diagnostic process – a MISS approach

Rising complexities of health care, ever-increasing advances, physician time constraints and often cognitive limitations have been responsible for the reversed diagnostic process. MISS approach starts with Management first without consideration of probable diagnosis with polypharmacy and if it does not work, then the next step is to Investigate, again without any clue to a provisional diagnosis and hence multiple tests are ordered at random hoping to get a diagnosis from one of the several tests. Such a process results in confusion more than a diagnosis. However, such a diagnosis even when obtained may not correlate with clinical profile and so may be erroneous. Finally, when both management and investigations fail to provide a diagnosis, it is time to ask for Symptoms and look for Signs on physical examination. These are shortcuts to the standard diagnostic process and such a reverse diagnostic process is prevalent in the modern era and is obviously a disaster.

Tests not for diagnosis but for confirmation

Diagnostic testing has become a critical feature of standard medical practice. Tests are expected to define anatomy, pathology and if possible, etiology and complement bedside medicine. The etiology of most diseases has been conjectural and remained elusive with an exception of infections. Limitations of tests must be kept in mind, sensitivity and specificity of tests need consideration. No test is 100% dependable as a negative test may not rule out disease and a positive test may not necessarily confirm the disease. For example, negative blood culture does not rule out bacterial infection and positive blood culture may be a contaminant or a commensal. Choosing appropriate tests need provisional diagnosis. Priority of ordering tests must be based on Sutton’s law – common things first. It is said that when you hear hoofbeats, think horses, not zebras. Ordering multiple tests to rule out every possibility is an increasing trend that is not justified. It is irrational, not cost-effective and stressful to a patient. Unfortunately, patients demand tests as they consider tests superior to clinical diagnosis and doctors find it convenient to shortcut the diagnostic process. At times, you end up treating tests and not the patient.

Missing “high-touch” medicine

Interaction with the patient while history taking and physical examination in a standard diagnostic process help to build a rapport and a bond between the patient and a doctor. It demonstrates concern, honesty, responsibility, accountability and transparency on the part of a doctor and instills faith, confidence, satisfaction and compliance on the part of the patient. It in many ways leads to divine healing. “High-tech” medicine deprives all such benefits and treats a patient as an inanimate object. Thus, “high-tech” medicine should be judiciously used only after the “high-touch” process is followed.

Personal notes

My teacher once told me that when he joined as a pediatric resident in UK, he had to undergo a routine health check before starting the post. A senior general physician examined him in detail including testing for the entire sensory system. My teacher was surprised as he thought this was a cursory requirement as young aspiring residents would be most healthy. He asked the physician why he had to examine in so much detail. To which, the physician asked whether it was not the way physicians conducted the clinical examination in India. My teacher understood the message and he became enlightened even before joining the post. It is common to find a junior colleague asking me for a second opinion because he has no clue to a diagnosis in spite of several investigations and trials with antibiotics. In one of such incidences, when I asked him what his provisional diagnosis had been, he quickly said he did not know and that was why he was requesting me to see his patient. This was a classical MISS approach. I recall a bright undergraduate student who had learned to take a detailed history including family history. He was taking a history of a lady who had fallen down from the 1st -floor gallery while putting clothes to dry and in thoroughness, he asked whether there was a history of any family member having fallen the similar way. He is today sincere rational doctor. The astute family physician observed mild puffiness of face, engorged neck veins and propped-up eyes in a person who had come for a minor illness and had no major complaints. The person was referred to a nephrologist, cardiologist and endocrinologist for an opinion on probable diagnosis but all tests were negative and each specialist vouched it was not the problem of his specialty. The person confirmed from his family physician that he had the unusual disease, the fate of which was unknown. So, he decided to enjoy his life before he could worsen and so planned a world tour. He went to a store to buy branded shirts. The Attendant asked for his collar size and when is said 16, the attendant said if you wear such a tight collar, you would get puffiness of eyes, engorged neck veins and propped-up eyes. The person knew his diagnosis.

Take home message

The diagnostic process in medicine should be followed sequentially in each patient – to find anatomy first, followed by pathology. (Medical curriculum is in the same sequence – it starts with anatomy and physiology and then goes on to pathology (it is disturbed physiology). Anatomy and pathology can be reasonably assessed by history and physical examination while etiology is guesswork based on critical thinking. It is only then that investigations should be ordered to confirm the probable diagnosis. Thus, tests are ordered as per the provisional diagnosis. It gives a thrill to a physician when minimum tests confirm the clinical diagnosis. Physicians must audit their clinical performance and it is the only way to be an accomplished doctor.

Chapter 4: Diagnostic process often reversed