need help with your account or subscription? click here to email us (or see the contact page)
join telegramNEW! discord
jump to exam page:
search for anything ⋅ score predictor (โ€œpredict me!โ€)

NBME 21 Answers

nbme21/Block 1/Question#46 (reveal difficulty score)
A 66-year-old man is brought to the emergency ...
Lipopolysaccharide stimulation of toll-like receptor ๐Ÿ” / ๐Ÿ“บ / ๐ŸŒณ / ๐Ÿ“–
tags: Immuno

 Login (or register) to see more


 +10  upvote downvote
submitted by โˆ—meningitis(643)
get full access to all contentpick a username

LPS found in outer membrane of gram โŠ bacteria (both cocci and rods). Composed of O antigen + core polysaccharide + lipid A (the toxic component).

Activates Macrophages and induces TNFalpha release -> Hypotension and fever.

Pg 133 Endotoxin.

get full access to all contentpick a username
zevvyt  and just to note answer b) "induction of histamine release" DOES happen , but it's not the "Initial Event" that the question asks for +1
unknown001  there you go, another introducer of confusion who dislikes straightforward questions +



 +5  upvote downvote
submitted by โˆ—nala_ula(127)
get full access to all contentpick a username

Toll like receptors are pattern recognition receptors (on innate immunity cells like macrophages) that recognize pathogen associated molecular patterns (PAMPs) and lead to activation of NF-kB. One example of a PAMP is LPS (gram negative bacteria). This leads to secretion of IL-1, IL-6 (cause fever), TNF-a (causes fever and hypotension), Nitric Oxide (causes hypotension).

Complement activation itself leads to hypotension via C3a, as well.

All this can be found on page 133 on FA, as @meningitis pointed out, and page 99 of FA 2019.

get full access to all contentpick a username



Must-See Comments from nbme21

nosancuck on Absorption atelectasis
assoplasty on Free T4
seagull on GM2
lnsetick on Apocrine
niboonsh on NMDA receptors are blocked by Mg2+ at the ...
drdoom on Deletion of a hydrophobic amino acid ...
hayayah on HCO3โˆ’ transported in the plasma
mcl on Aortic
notadoctor on Usual interstitial pneumonitis
madojo on Genital herpes
hungrybox on Obstruction of the bile duct
jambo2222 on Lung
hungrybox on Mismatch repair
hungrybox on Hydrochlorothiazide

search for anything NEW!