Mehlman anaphylaxis/atelectasis/scombroid/shellfish (09-30) (1)

Question 1

Atelectasis. also refers to ,,lung collapse” or ,,colapse of alveoli”

Answer 1

.

Question 2

Atelectasis. highest yield point for usmle?

Answer 2

It is the most common cause of
fever within 24 hours of post-surgery.

extremely important

Question 3

Atelectasis.
Q: woman had a C-section two days ago and the answer was still atelectasis, so even though it’s most common <24 hours, just be aware one Q exists where, oh em gee, it’s 2 days later

Answer 3

.

Question 4

Atelectasis. mechanism combo of what?

Answer 4

The mechanism is related to combo of pain meds + sedentation, where breathing becomes slower + shallower in hospital bed, leading to mild collapsing of some alveoli. This is why breathing exercises can be important post-surgery

Question 5

Atelectasis. presentation on CXR?

Answer 5

Will often present as bibasilar shadows or opacities.

Question 6

Patient had surgery yesterday + now has fever + CXR shows mild opacity at the lung bases -> answer = ?

Answer 6

atelectasis

Question 7

Atelectasis. there is also ,,obstructive/resoptive” atelectasis. what happens in this?

Answer 7

This is when an area of lung distal to an obstruction from, e.g., a tumor, can cause alveoli to collapse. This then increases the chance for pneumonia distal to the obstruction

Question 8

Atelectasis. cia biski out of box klausimas, buvo prie pneumoniju aptarta tos endobronchines obstrukcijos.

distal area of lung collapse (i.e., atelectasis) in patient with lung cancer?

Answer 8

“endobronchial obstruction”

“vascular occlusion by tumor” is wrong answer (makes sense, as the tumor
obstructs the respiratory tree, not blood vessel, in this case, but I’ve seen students accidentally choose the latter).

Question 9

ANAPHYLAXIS. CP in Hx of what?

Answer 9

Acute dyspnea and bilateral wheezes in patient who was gardening (stung by a bee), who ate a particular food (e.g., peanuts), or who was commenced on a recent drug (e.g., TMP/SMX).

Question 10

ANAPHYLAXIS. vignette what often gives?

Answer 10

tachycardia and low BP.

Question 11

ANAPHYLAXIS. mechanism?

Answer 11

Mechanism is IgE crosslinking on surface of mast cells and basophils that leads to degranulation and histamine + prostaglandin release.
Eosinophils can be recruited in response.

Question 12

ANAPHYLAXIS. USMLE wants what arrows?
vascular resistance, CO, PCWP?

Answer 12

DECR. vascular resistance, INCR. CO, decr. or non-changed PCWP.

Question 13

ANAPHYLAXIS. Tx?

Answer 13

Intramuscular epinephrine

Question 14

ANAPHYLAXIS. epinephrine mechanism in this pathology 2?

Answer 14

the strong b2-agonistic effect opens the airways; the strong a1-agonistic effect constricts the arterioles and restores BP.

Question 15

ANAPHYLAXIS.
“In addition to self-injectable epinephrine therapy, what is most appropriate therapy to DECR. recurrences” ? huj znaet pirma kart girdziu, also mechanism

Answer 15

Venom immunotherapy (VIT)
What this does is desensitizes the patient to the antigen by allowing him/her to develop neutralizing IgG antibodies against it.

Question 16

Scombroid. misdiagnosed with what?

Answer 16

Seafood allergy.

Question 17

Scombroid. mechanism? IT IS NOT ALLERGY

Answer 17

Bacteria in decaying meaty fish (e.g., mahimahi) can break down histidine in the fish into histamine, which causes an allergic-/asthma-like presentation.

Question 18

Scombroid. who has higher mortality?

Answer 18

Patients with history of asthma have greater risk of mortality.

Question 19

Shellfish allergy. can cause what presentation?

Answer 19

Can cause allergic-/asthma-like presentation.

Question 20

Shellfish allergy. when does it occur?

Answer 20

Occurs LITERALLY after eating shellfish (i.e., clams, mussels).

Question 21

Shellfish allergy.

Don’t confuse with scombroid. Students get trigger-happy when they learn weird conditions. If USMLE gives shellfish, the answer is shellfish allergy, not scombroid. The latter is from meaty fish and not an allergy.

Answer 21

.