Acute and Chronic Signs and Symptoms
I recently purchased a new computer. After agreeing to abide by a license agreement the length of a Tolstoy novel, I was confronted with a number of perplexing messages. I was directed to "Tag selected media…" and I was instructed that "…the destination isn’t formatted as NTFS, FAT or Universal Disk Format (also called Live File System)." Now, I readily confess that I am not a computer whiz, but I humbly submit that neither do I consider myself a cyber-knucklehead. Regardless, I have absolutely no idea what this computer is trying to tell me. I suspect that this is how a non-medical person feels when informed that a rash "appears to be a subacute exanthem" during a visit to the doctor. Therefore, before I call the person waiting in India to receive my call in customer support, this might be a karma-enhancing opportunity to explain how to convey valuable information to one’s health care provider during your next clinic visit.
One of the most valuable pieces of information to your health care provider is the time course of your illness or injury. Some conditions occur suddenly and without warning, like a twisted ankle from an awkward step off of a ladder or an episode of diarrhea after spending the weekend with a friend who had similar symptoms. These conditions are called "acute" injuries or illnesses. The body generally reports the onset of such problems with an unmistakable and immediate message in the form of pain or malfunction. It is important to make a mental note of such injuries, because such accidents may be easily forgotten in the heat of the battle and only later be recognized as the possible source of subsequent symptoms that might be even more annoying than the original injury.
If "acute symptoms" linger or progress, then they are often referred to as "subacute symptoms." Subacute conditions typically have a slightly slower onset and have a naggingly prolonged period of recovery. An example of subacute symptoms might be back pain after a week of hauling dirt in a wheelbarrow, or coughing after replacing the insulation in one’s attic. You will notice that the severity of an acute illness is often a direct result of the nature of the offending event or germ, such as how far one fell from the ladder or whether an episode of diarrhea was caused by a common virus or by the cholera bacteria. In contrast, the severity of a subacute illness is often determined by the amount of inflammation that results from an original injury.
Inflammation is evidence of the body’s attempt to heal. The amount of inflammation that develops in a particular patient with a subacute problem is often at least partly the result of certain characteristics of the patient in question, such as whether they have a 60-year-old spine with arthritis, or whether they have a particular allergy to attic dust or insulation fibers. People with subacute illnesses often have intrinsic conditions that prolong the period required for natural recovery, or they may simply have a condition that requires more time to heal. Deciding whether to engage in further testing for such patients often requires a fair amount of head-scratching by the clinician.
The third category of illness is reserved for "chronic" conditions. Because our natural healing mechanisms function differently for different parts of the body, whether or not an illness is considered chronic is determined by the part of the body affected by the condition. For example, diarrhea is considered chronic after it continues for four weeks, but a cough is considered chronic after it persists for eight weeks or more, and back pain is considered chronic when it persists for longer than twelve weeks. While there are certain tests and treatments for acute and subacute conditions, recommendations for further (and often more costly and complex) tests or treatments are usually triggered when patients meet the criteria for chronic illness.
It should be mentioned that such thresholds for defining "chronic" illness are somewhat arbitrary. For any particular patient, a care giver may adjust their diagnosis according to any number of variables, such as degree of disability, occupational requirements, risk factors, severity of pain, coincidental conditions etc… On the other hand, being familiar with when our normal healing mechanisms have proven to be insufficient is information that is helpful if we are to make the most efficient use of our health care system. Knowing when an acute condition requires the attention of our care givers is important, and knowing when persistent symptoms require further investigation and treatment is also worthwhile.
Another distinction that may be helpful to make is the difference between signs and symptoms of illness. When a patient enters the exam room complaining of a painful ankle, we call that complaint a "symptom." However, when the patient limps down the hallway, we call that a "sign" of the problem. Similarly, my exasperation with being unable to store information in my computer is a "symptom," but the fact that I may have the power cord plugged into the ear phone jack is a "sign" of the problem.