In general, acute conditions occur suddenly, have immediate or rapidly developing symptoms, and are of limited duration (eg, the flu). On the other hand, chronic conditions are long-lasting. They develop and can get worse over time (for example, Crohn's disease).
However, these descriptions may differ slightly depending on who you speak to or the sources you are referring to. While these terms may apply in certain circumstances, they are not always, and often do not fit the description of what you might encounter if you are diagnosed with an acute or chronic diagnosis.
Most diseases can be classified as acute or chronic. These terms can indicate the types of treatment needed, the expected duration of treatment, and the appropriateness of the treatment.
Acute does not mean new, although many newly diagnosed illnesses present with acute symptoms. It also does not mean that the symptoms are severe. It simply means that symptoms have developed rapidly and some form of medical intervention is needed.
Similarly, a chronic illness shouldn't mean death or something that inherently shortens your life. It simply indicates that the condition is incurable. Chronic conditions can often be treated (such as diabetes or high blood pressure ).
A newly diagnosed disease can also be called chronic if no cure is expected; arthritis is one such example. Some broaden the definition to include developmental, functional, or visual disabilities that require ongoing care or treatment.
Phases of the disease
An acute or chronic diagnosis is not necessarily fixed. Sometimes an acute condition can become chronic, while a chronic condition can appear suddenly with acute symptoms.
Some infections, for example, will go from an acute phase (in which symptoms appear and disappear after initial exposure) to a chronic phase (in which the infection persists but progresses less aggressively).
A chronic infection can lie dormant for years and then present with new and usually serious acute complications .
The same can happen with non-communicable diseases like rheumatoid arthritis or psoriasis . Both diseases are considered chronic because they are not treatable, but they can be managed with proper care and treatment.
Even so, diseases can have episodic exacerbations, in which acute symptoms arise and disappear spontaneously.
With early diagnosis and treatment, some chronic diseases can remain subclinical (without easily observable symptoms) and never become acute. These include infections like HIV or conditions like hypercholesterolemia (high cholesterol), which are often caught early and treated before symptoms appear.
Where the definitions are not true
As clear-cut as the definitions may seem (six months or more for a chronic illness vs. less than six months for an acute illness ), this time period in no way suggests what you might face if you are diagnosed with an acute or chronic illness.
After all, an acute flu does not compare to an acute hepatitis C infection. Also, HIV (a chronic infection that can be controlled with antiretroviral drugs for life) does not compare to multiple sclerosis (a chronic disease that progresses invariably despite treatment). ..
After all, labeling an illness as pleasant or chronic cannot describe the nature of the illness or predict the outcomes.
This lack of specificity in definitions affects not only healthcare providers and patients, but also researchers looking for concise ways to assess the course of the disease. The thresholds often change from six months to three months, or extend to a year or more, adding to the confusion.
Even public health authorities are not immune to these inconsistencies. For example, the US Department of Health and Human Services (HHS) classifies 20 diseases as chronic. – including stroke, autism and cancer – while the Centers for Medicare & Medicaid Services (CMMS) lists 19, many of which differ from the HHS list.
In this context, the definition can often be changed to suit the situation. In HHS, the term chronic is used to describe a public health problem for surveillance purposes. In CMMS, the term broadly describes a medical condition.
Currently, there is no single uniform definition of acute or chronic disease that fits all purposes. However, this does not mean that these terms are unimportant in the way they are used between the healthcare provider and the patient.
Seemingly casual uses of these terms can often confuse patient expectations.
For example, can cancer really be considered chronic if only a few types (such as multiple myeloma ) can be treated chronically? Should an injury, such as a broken leg, be considered acute, even if it fits the broader definition of the term?
After all, defining an illness or injury as acute or chronic may not only be necessary, but confusing rather than enlightening.
Some health experts advocate a simpler approach that will help eliminate confusion and inconsistencies. Rather than sticking to a specific time frame or a list of conditions, they support definitions that express the concepts behind the terms more generally.
The Merriam-Webster dictionary, for example, defines them as follows:
- Acute : "sudden onset, sharp rise and short current."
- Chronicle : "Continue or repeat over and over again for a long time."
By understanding the concepts, not the rules, you can better understand what your doctor is telling you when describing your health condition. But of course, be sure to ask any questions you have to paint a clear picture of your condition and what could happen.