Diagnosis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

The diagnosis of gout is based upon the identification of intracellular monosodium urate (MSU) crystals in the synovial fluid aspirate of an affected joint, under polarizing light microscopy. But when this is not possible, a clinical diagnosis can be deduced with the help of classical clinical features, including the history and physical examination, laboratory findings, and various imaging studies.

History of medical diagnostics

The history of medical diagnosis began in earnest from the enlightened days of Hippocrates in ancient Greece but is far from perfect despite the enormous bounty of information made available by medical research including the sequencing of the human genome. The practice of diagnosis continues to be dominated by theories set down in the early 1900s.

Ancient Greece

Over two thousand years ago, Hippocrates recorded the association between disease and heredity. In similar fashion, Pythagoras noted the association between metabolism and heredity (allergy to Fava beans). The medical community, however, has only recently acknowledged the importance of genetics and its relevance to mainstream medicine.

The Oslerian ideal

The ideals of William Osler who transformed the practice of medicine in the early 1900s were based on the principles of the diagnosis and treatment of disease. According to Osler, the functions of a physician were to be able to identify disease and its manifestations, understand its mechanisms, how it may be prevented and how it may be cured. For his medical students he believed that the best textbook was the patient himself – analysis of morbid anatomy and pathology were the keys. The Oslerian ideal continues today, as the basis of the Doctor’s strategy is, "What disease does this patient have and what is the best way for treatment?" The emphasis is on the classification of the disease in order to use the remedies available for its effects to be reversed or ameliorated. The human being in question is representative of a class of people with this type of disease whereas the biological individuality of this person is not given any great weight.

Garrod's view

The successor to William Osler as Regius Professor at Oxford was Archibald Garrod. Garrod echoed the observations of his Greek counterparts of two millennia ago, ...our chemical individualities are due to our chemical merits as well as our chemical shortcomings; and it is more nearly true to say that the factors which confer upon us our predispositions to and immunities from various mishaps which are spoken of as diseases, are inherent in our very chemical structure; and even in the molecular groupings which confer upon us our individualities, and which went into the making of the chromosomes from which we sprang. Considering that the time that he formulated these ideas were the early 1900's, and the knowledge of DNA encoding genes that in turn encoded proteins responsible for bodily structure and functions not being discovered until some fifty years later it took some time before medicine could fully appreciate the fundamental importance of his concept of diagnosis.

Present-day Oslerian practice

Whereas Osler laid the founding principles by which medicine should be practiced, Garrod placed these principles in a greater context of a chemical individuality that is inherited and is subject to the mechanisms of evolutionary selection. The Oslerian ideal of medical practice continues to dominate medical philosophy today. The patient is a collective of symptoms to be characterized and analyzed algorithmically in order to draw a diagnosis and subsequently produce a strategy of treatment. Medicine is about problems based solutions. In keeping with this philosophy, today's pathology reports provide a momentary snapshot of the patient's biochemical profile, highlighting the end result of the disease process.

Influence of DNA technology

Garrod's conception of biological individuality was confirmed with the advent of the sequencing of the human genome. Finally the subtle relationship between inheritance, individuality and environment became apparent via the variations detected in DNA. In each patient's DNA lies a script for how their bodies will change and become ill as well as how they will handle the assaults of the environment from the beginning of their life to its end. It is hoped that by knowing a patient's genes that the biological strengths and weaknesses in respect to these assaults will be revealed and disease processes can be predicted before they have the opportunity to manifest. Although knowledge in this area is far from complete, there are already medical interventions based on this. More importantly, the physician, forewarned with this knowledge can guide the patient towards appropriate lifestyle changes to anticipate and mitigate disease processes.

See also

• Diagnosis codes
• Differential diagnosis
• Diagnosis of exclusion
• Diagnosis (artificial intelligence)
• Diagnosis-related group
• Disease
• Diagnostic and Statistical Manual of Mental Disorders
• Doctor-patient relationship
• Etiology
• International Statistical Classification of
  Diseases and Related Health Problems (ICD)
• Medical classification
• Medical history
• Medical imaging
• Medical record
• Medical test
  • Biopsy
  • Blood pressure
  • Blood tests
  • Diagnostic testing
  • Electrocardiogram
  • Fecal tests
    • Fecal occult blood test
    • Fecal fat test
  • Genetic testing
  • Hydrogen breath test
  • Pulse
  • Saliva tests
  • Stethoscope
  • Urine tests and urinalysis

• Medicine
• Mental illness
• Merck Manual of Diagnosis and Therapy
• Misdiagnosis and medical error
• Nocebo
• Nosology
• Nursing diagnosis
• Pathogenesis
• Pathology
• Patient
• Physical examination
• Physician
• Preimplantation genetic diagnosis
• Prenatal diagnosis
• Prognosis
• Pulse diagnosis
• Reasoning applicable to diagnosis:
  • Abductive reasoning
  • Common sense
  • Deductive reasoning
  • Defeasible reasoning
  • Inductive reasoning
  • Inference
  • Inquiry
  • Retroduction
• Self diagnosis
• Therapy
• Trashcan diagnosis

Lists

• List of diseases
• List of disorders

• List of medical symptoms
• Category:Diseases

External links

• GPnotebook web site GPnotebook is a British medical database for GPs that provides an immediate reference resource for clinicians worldwide. The database consists of over 30,000 pages of information.
• Free 24/7 DRG & ICD-9-CM lookup powered by Flash Code at icd9coding.com
• Differential Diagnosis
• Merck Manual of Diagnosis and Therapy