PDA Question

[Roy7]

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Okay, I just did a Kaplan Qbank question like this:

What disease will make a baby cyanotic on bottom and pink on top.
Answer choices were basically between an infantile coarctation of the aorta and a PDA.

I went w/PDA because RR and Goljan said that infantile coarctation usually is w/turners syndrome and requires surgery immediately and doesnt have the differential cyanosis going on (adult has em). And on page 180 RR it clearly indicates the PDA has differntial cyanosis.

Yet at the Qbank explanation it says that PDA doesnt have differential cyanosis.

Who do I go with? It's a pretty big concept that I can def. see being tested.

 

[pleaseletmepass]

Okay, I just did a Kaplan Qbank question like this:

What disease will make a baby cyanotic on bottom and pink on top.
Answer choices were basically between an infantile coarctation of the aorta and a PDA.

I went w/PDA because RR and Goljan said that infantile coarctation usually is w/turners syndrome and requires surgery immediately and doesnt have the differential cyanosis going on (adult has em). And on page 180 RR it clearly indicates the PDA has differntial cyanosis.

Yet at the Qbank explanation it says that PDA doesnt have differential cyanosis.

Who do I go with? It's a pretty big concept that I can def. see being tested.

I am not sure how the question was worded but I am going to assume that they were referring to a newborn infant. At birth, aortic coarctation should produce the differential cyanosis (blood has difficulty reaching lower extremities), while a PDA would not produce this effect. However, in the case of PDA, as the infant develops, continuous blood from the aorta into the pulmonary artery (via the patent ductus) creates pulmonary hypertension and right ventricular hypertrophy. Without intervention, this would continue until there was a reversal of flow from the pulm artery into the aorta (surgery or indomethicin can be use to close the PDA). At the point of shunt reversal, the baby would then develop differential cyanosis.

At least that's the way I understand it...I have been known to be wrong on more than one occassion so...😀

-pleaseletmepass

 

[Roy7]

No actually that makes perfect sense.
Thanks!

 

[grety1]

Remember depending on the extent of the PDA, you will get GENERALIZED none to severe cyanosis, depending on the degree of deoxygenated/oxygenated blood mixing. (SYSTEMIC mixing is the key pathological issue.)

With pink on top and blue on bottom, oxygenated blood is getting to the top just fine but not to the bottom-->more than likely some kind of obstruction. Quite suggestive of coarctation.