Disease characterization and classification
In the medical field, a disease may be regarded as any objectively addressable deviation from the abstract normal. That abstract normal would be assigned a “neutrum” of customarily and/ or scholarly defined state of equilibrium and perfection.
Very remarkable is that the human normal is not shaped, as may be noticed in the phrase above, only by physicians or medical professionals, but also by thinkers, philosophers, scientists, creative minds and the general lay people.
In order for such “disease” to be defined or characterized a few parameters should be fulfilled.
- Type of the person in whom this disease may be seen.
- Onset of the disease.
- Course of the disease.
- Associates of the disease.
- Common outcome of the disease.
- Name of the disease.
These are 6 parameters that would be quite sufficient to characterize a disease on gross and perceivable measures by scholars and the lay as well. The knowledge about the cause(s) and underlying micro changes and molecular mechanisms fall to the interest of a few people including the health care providers.
Let’s talk briefly about each of these disease parameters in hand of common examples.
Type of patient includes:
– Age (child, adolescent, adult, and elderly),
– Sex (male and female),
– Stature (stunted, average, above average)
– Body shape (slim, average, obese),
– Race (Caucasian, Negroid, Mongolian),
– Personality (easy, strict),
– Acquaintance (poor, average, high).
The relevance of patient’s type to the disease is understood by the fact that some diseases are more common in some patient’s types than in other types.
Onset of the disease
This means how the disease was noticed by the patient or the relatives.
– Sudden onset: the disease has commenced very acutely. Example: a thrombus formation in the leg (deep venous thrombosis, DVT).
– Gradual onset: the disease commence over relatively long time. Example: weakness in the leg due to a disc hernia.
Course of the disease
This describes whether the disease tends to increase, decrease or fluctuate as time passes (over relatively long time) without any interference from the patient’s side.
– Progressive course: e.g. progressive decrease in visual acuity.
– Regressive: e.g. so-called self-limiting disease that resolves gradually by itself such as common cold or flu.
– Intermittent course: this describes a disease that tends to appear from time to time.
Associates of the disease
These imply the relation of the disease to other things like food, drinking, activity, stress, posture, etc. Among the associates of the disease we can consider risk factor(s), e.g. obesity is a risk factor for type 2 diabetes mellitus, and precipitating factor(s), e.g. water restriction is a precipitating factor for renal troubles.
Common outcome of the disease
This is how the disease would most probably set its end.
– Self-limiting, self-curable: usually no treatment is needed.
– Ailing and incapacitating: treatment is needed.
– Life threatening or fatal: treatment is needed.
Name of the disease
This is important because it helps in reliably and efficiently preserving and communicating knowledge about disease.
The terms: “natural history of the disease” and “the full blown picture of the disease”, are helpful in presenting the disease as well characterized entity with its unique components and behavior.
In the realm of disease a classification system may be very necessary in order for easy sorting and recall to be in hand. It is anyhow not an easy job to classify diseases at any known or unknown factor, e.g. their causes. As medical practitioners and students we used to have medical terms such as:
– Infectious diseases and noninfectious diseases
– Organic and psychological diseases
– Genetic and acquired diseases
In addition to other terms like trauma, congenital, psychosomatic and constitutional.
From a practical and treatment-wise approach, I would classify diseases into two main classes: biologic and nonbiologic. In the former class some living organism, e.g. a bacterium, a virus, a parasite such as E. histolytica or a worm, is almost certainly accused for making the disease. In such a case the effects of such biologic invasion must be well assessed and specific treatment may be given as appropriate. Such a microbe- or parasite-oriented treatment may be in some cases life saving as the timely diagnosis and treatment are crucial for favorable outcome. For the latter class of diseases, in which such accusation of an invading organism is quite unlikely to bring about the disease, the treatment will be chiefly concerned with combating the illness through general and/ or specific treatments.
Now, I wish to present a master for patient’s diagnosis that would be comprehensive and elegant as well:
* Moderate jaundice in otherwise apparently normal 3 days female neonate of type 2 diabetic mother for general treatment and investigation.
* Renal colic in other wise apparently normal 6 years boy for general treatment and investigation.
* Moderate fever (38⁰C) in reportedly hypertensive obese; easy taker 49 male adult for specific antibiotic treatment and advisable investigation.
* Slight Albuminuria (+) in otherwise apparently normal; tense taker 19 weeks primigravida, 32 female adult for mandatory weekly-monthly follow up.
This 5-site patient’s diagnosis comprised: 1) patient’s most relevant complaint or finding, 2) patient’s look and/or medical history, 3) patient’s type, 4) suggested treatment, and 5) investigation.
With the expected advancement of disease characterization more molecular designations will be available for common use that would reflect an increasing awareness of molecularly-oriented medicine.