NBME 17 Additional testing to confirm the diagnosis of TA (NBME Answers)

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submitted by ∗kstebbins(24)

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I was thrown off because Pathoma/Dr. Sattar and pixorize say it is critical to start steroids ASAP to avoid permanent damage to the ophthalmic artery and blindness in patients suspected of having Giant Cell (Temporal) Arteritis.

This means not waiting for diagnostic confirmation.

However a 99% sensitivity does not equate to a 99% certainty of GCA/TA. So additional testing is the best answer choice even though her elevated ESR gives us strong suspicion of GCA/TA.

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nsinghey exactly, the reason why its not steroids is because that answer choice says the diagnosis of TA has been established with 99% certainty which is NOT true +3

j44n this question threw me because you tx this on clinical suspicion alone. So i was torn between the right answer and the fact that if you repeated ESR again and its positive you youd the give steroids +5

kcyanide101 This is how i see it. Firstly, the question states that glucorticoid has a severe adverse effect. Implying you have to be very sure the patient has TA before administration. Now, remember that Sensitivity rules out Disease, while specificity rules in. Basically, if you use a highly sensitive test and test negative it means you really don not have the disease. On the other hand if you use a highly specific test and test positive you truly do have the disease. In this case the sensitivity of the ESR is 99%, meaning people who test negative with it have no ongoing inflammation/chances of TA. On the other hand it's specificity is 60% which means that the positive result of anyone who tests using ESR can't be trusted as being too reliable. As such, further testing is needed to confirm it.... In this case option A PS... in hospital setting you just give glucorticoid. This question is more or less hypothetical I presume. +2