What's different about geriatrics? Paradigm

There are some important differences between the rest of medicine and geriatrics. The first I want to discuss is paradigm.

To me, a paradigm is a particular way of thinking which involves certain assumptions, implicit or explicit, about how things work and allows humans to think about topics and to work with them. Paradigms all have strengths and limitations.

An example in medicine is the biological model of disease. Briefly, the physical organism has an external influence which alters it's function. That produces changes which are sensed by the mind, producing unpleasant sensations - disease. To remove disease then, find the external influence and remove it or if that's not possible return the function to normal and no more disease. This paradigm has strengths but also weaknesses - it ignores the effect of psychological and social influences on the progression of disease.

A similar paradigm of thought in medicine is the hypotheticodeductive model. IN this way of medical thinking, the doctor interacts with the patient and step by step gathers information, along the way forming hypotheses about what is causing the disease, testing them by gathering more targeted information, and refining or discarding them. Information can be gathered by talking, testing or even trials of treatment. Finally one diagnosis is reached and the appropriate treatment can be prescribed. Again this model has strengths and weaknesses.

There are other models of medical thinking however, for example, in intensive care units, the hypotheticodeductive model is used, but treatment can also be prescribed without a diagnosis, on the basis that although the cause is unknown, it is clear which organ is not functioning and needs support.

The hypotheticodeductive system is appealing in it's utility and simplicity and is the major model used in medicine, but it often fails in geriatrics. This is because problems in geriatrics are rarely the result of a single diagnosis. One of the fundamental factors in aging is homeostenosis - if you're not familiar with this I will be posting on it soon. Homeostenosis is not an even process however, and some processes are more susceptible to than others. A factor, indeed sometimes it seems like almost any factor results in a perturbation in homeostasis, which produces disease. Most sensitive to perturbation are the the homeostatic processes whose dysfunction results in the giants of geriatrics - balance so falls, continence so incontinence, intellect so confusion, movement so immobility.

Another way of explaining this more simply is the weakest link. As you age, some systems become weaker than others. when something happens to cause a disease, where in a young person that might affect the particular organ that's in, in an older person it affects the weakest link first.

The factor that affects homeostasis could be anything, and usually there is more than one. I've found it useful to borrow a classification from the psychiatrists, the predisposing/precipitating/perpetuating way of classifying factors contributing to disease. In this way of thinking, disease is caused by combinations of underlying or predisposing factors, often with a precipitating factor, and prolonging or perpetuating factors that continue the illness. The psychiatrists also classify these factors by their type - biological, psychological or social, which I find less though sometimes still useful.

The problem comes when doctors trained in hypotheticodeductive thinking apply that to geriatric problems. The result of that thinking is that they will come up with a single diagnosis and expect treatment of that to improve the problem, ignoring all those other factors.

For example, a patient presents with urinary incontinence. The hypotheticodeductive thinker finds a urinary tract infection and treats it, but the patient doesn't improve. Why? THe underlying predisposing factor may well be benign prostatic enlargement resulting in retention of abnormal volumes of urine in the bladder after voiding. The acute precipitant to the incontinence was the urinary tract infection, but the perpetuating factor is the constipation resulting from decreased fluid intake as the patient tried to treat the incontinence himself, which worsens the urinary retention causing overflow incontinence. Treat just the infection and the patient not only will not get better, but also you will miss an opportunity to prevent further problem by correcting the underlying predisposition.

That was a fairly simple example. Often, there are many factors fitting into all categories, some of which are reversible or treatable, some of which aren't.