00:00Imagine two hypothetical patients, one a pregnant young woman, and the other a middle-aged woman with no known medical
00:10conditions.
00:11They both complain of sudden-onset pain, swelling, and redness in the right knee.
00:18One of these patients has a dangerous infection in the knee joint, and the other has a non-infectious scalp
00:27flare of the knee.
00:28Now, if we were to try to tell these two patients apart by examining their ESR alone, we would be
00:38setting ourselves up for failure.
00:41Now, here's why.
00:43The problem we face in this hypothetical case is that septic arthritis often causes the ESR to rise, and gout
00:55can do the same thing.
00:56But while the degree to which these two diseases cause the ESR to rise may differ, the ranges may overlap.
01:07This means ESR cannot reliably separate one from the other.
01:13By attempting to use the ESR readings alone to distinguish these patients, doctors may miss a potentially life-threatening infection
01:23of the knee.
01:25Missing an infection like that could potentially end in the death of one of these patients.
01:33A high ESR can herald the presence of many different diseases.
01:39Some of these conditions can be serious.
01:42Now, because of their clinical presentation, ruling out septic arthritis in our two hypothetical patients is an urgent matter.
01:54Missing septic arthritis can destroy the joint, spread infection into the bloodstream, and in severe cases, become fatal.
02:05Despite this danger, the ESR would give us no clue that we are dealing with two completely different patients.
02:14Our two hypothetical patients both have an ESR of 40 millimeters per hour.
02:22So, what good is the ESR?
02:26ESR is a test developed over 100 years ago as a method of detecting inflammatory conditions in the body.
02:34Originally, doctors noted that red blood cells of patients with blood infections settled more quickly when allowed to sit in
02:44a narrow glass tube.
02:45This is due to the buildup of acute phase proteins in the blood that decrease the repulsive forces that naturally
02:55exist between red blood cells.
02:58During inflammation, the body releases inflammatory signals such as interleukin-6.
03:05These signals stimulate the liver to produce acute phase proteins such as fibrinogen and CRP.
03:16Fibrinogen makes red blood cells stick together more easily, forming large clusters that settle faster in the test tube.
03:27That faster settling is what causes the ESR to rise.
03:33Unfortunately, there are many factors that can affect the rate at which red blood cells settle in a test tube.
03:42One of these is pregnancy.
03:45Pregnancy raises the ESR.
03:48This means that a healthy pregnant woman can be expected to have a higher ESR than a woman who is
03:57not pregnant.
03:58In this case, a slight elevation in the ESR from gout coupled with the increase in ESR from pregnancy makes
04:09the setting apart of these two conditions based on ESR alone impossible.
04:16So even though both patients have the exact same symptoms and they both have an ESR of 40 millimeters per
04:24hour, they are vastly different patients.
04:29One may ultimately need urgent drainage and antibiotics.
04:34The other may only need anti-inflammatory treatment for gout.
04:39So what should the good doctors do?
04:42They will have to perform other studies to make a diagnosis.
04:48This hypothetical case illustrates a fundamental truth.
04:53ESR should never be evaluated in isolation.
04:59ESR should always be evaluated with the whole condition of the patient taken into consideration.
05:06In the pregnant patient, the ESR of 40 may be influenced by pregnancy and by the inflammatory process itself.
05:17In the middle-aged patient, the same ESR may accompany septic arthritis.
05:25The number is the same, but the danger is not.
05:31This is the danger of using ESR as a master instead of a servant.
05:37An ESR of 40 does not tell you whether the knee is infected, whether it is gout, or whether pregnancy,
05:46anemia, age, or another condition is influencing the result.
05:51In a patient with a red, swollen, severely painful joint, septic arthritis must remain on the table until it is
06:01properly evaluated.
06:04That may require urgent assessment and, in many cases, analysis of the joint fluid itself.
06:12Our doctors would only be able to differentiate between these patients by performing an arthrocentesis, that is, drawing fluid from
06:23the knee to look for infection or crystals.
06:27The ESR can support the investigation, but it cannot make the diagnosis by itself.
06:35I hope you enjoyed this video, I hope you found it useful, if you did, like, comment, share the video
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06:48Until the next video, stay healthy and stay safe.
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