Acute or chronic?

No matter how much clear today's evidence based medicine gets, one thing will be always hazy.

Acute, subacute and chronic are concepts related to time. Thus they relative to each other.

A bout of vomiting that began 1 minute ago is acute, and so is acute chest pain since 1 hour. But when a young man complains of back ache since yesterday, will it cease to be acute?

A look at the dictionary will tell you "acute" can be used in two different ways :
1.
(of an unpleasant or unwelcome situation or phenomenon) present or experienced to a severe or intense degree.
Example-
"an acute housing shortage"

2.
(of a disease or its symptoms) severe but of short duration.
Example-
"acute appendicitis"

Acute is derived from the Latin word "acus" which means"needle", thus auguring well the above two meanings.

Similarly, the meaning of chronic on Google is

- (of an illness) persisting for a long time or constantly recurring.
Example-
"chronic bronchitis"

Chronic is derived from Greek "Khronos" which means "time", again matching with the meaning.

Subacute is vaguely defined as something that is between acute and chronic.

Point to be noted is that - all these three words are "adjectives" and not "adverbs". Thus they describe the noun ie the patient or the disease and not the "verb" or the action that the disease is causing.

Acute Appendicitis tells you that the patient suffered from SEVERE Appendicitis FOR A SHORT TIME. And not that "it progressed quickly".

Similarly Chronic Bronchitis tells you the patient has Bronchitis that recurred many times over a period of time or is present since a long time. It doesn't mean that "there was an episode of bronchitis 1 year ago".

Many doctors use a simple Funda -
Acute - minutes to hours
Subacute - hours to days
Chronic - days to weeks.

However this "minutes to hours to days to weeks" stands for progression of disease and not "how many hours or weeks ago he had that episode".

I hope this clarifies the long standing confusion on this topic.

# whenever in doubt, refer to the etymology of the words #