The big difference between the words disease and syndrome is how they relate to the understanding of the medical community. A disease is a condition that has a known cause, a fairly consistent set of symptoms, and a quantifiable alteration of a person’s anatomy. A syndrome is a condition where there are a set of signs and symptoms that often go together, but the cause is unknown, and there isn’t always a measurable anatomical alteration. In some cases, a syndrome ends up being reclassified as a disease when scientists eventually understand the underlying cause and full effect. There are also cases where a syndrome is actually the result of a diverse set of different causes.
From a patient's perspective, there really isn’t that much of a difference between disease and syndrome effects. Patients suffering from a syndrome may experience all the same difficulties as people suffering from a disease, and it may be even more difficult for them because of treatments. Many syndromes can’t be cured, so the treatment is usually focused on symptoms only. Disease and syndrome conditions can both make people sick, and they can have a huge detrimental effect on a person’s quality of life.
A possible way to understand the difference between the terms disease and syndrome is to look at some examples of each and compare them. Lyme disease is generally a good example of the first. It is caused by bacteria carried inside the bodies of ticks, and they get into the blood stream through a bite. There is a fairly well-defined set of symptoms, including rash, joint pain and flu-like effects. Not every patient has every symptom, but there is generally a greater level of consistency than doctors see in many syndromes. It normally produces several reliable and quantifiable changes to the anatomy, including inflammation, organ damage, and eventual damage to the nervous system.
Chronic fatigue syndrome (CFS) is a pretty well-known condition that is generally a good example of a classic syndrome. People suffering with CFS have many symptoms in common, but they may also have a lot of symptoms that aren’t necessarily consistent. Doctors still aren’t sure whether CFS is related to one disease or if many different diseases might be causing a lot of similar symptoms. In order to define CFS as a disease, doctors would need a specific underlying cause for all cases and some kind of consistent quantifiable change in anatomy.