to snoo-finity ... and beyond!
to snoo-finity ... and beyond!
After the cuff is tied, the cells and tissue distal to the cuff will continue consuming ATP (ATP->ADP), but no fresh blood will be delivered to “clear” what will be an accumulating amount of ADP and other metabolites. ADP (=Adenosine) is itself a proxy of consumption and drives vasodilation of arteries! (Evolution is smart!) Increasing ADP/Adenosine in a “local environment” is a signal to the body that a lot of consumption is occurring there; thus, arteries and arterioles naturally dilate to increase blood flow rates and “sweep away” metabolic byproducts.
Which of the following reasons is why this question is bull?
1) Using the word "cyclic" instead of tricyclic for clarity
2) Knowing all of epidemiology of all drugs
3) having to reason out that anticholinergic effects are probably the worst over alpha1 or H1 effects to no certainty.
4) The crippling depression of studying for days-to-weeks on end to probably do average on the test.
There was a uworld Q on this. The duration of action of Succinylcholine is determined by its metabolism by plasma cholinesterase. Some people are homozygous for an abnormal plasma cholinesterase, aka "pseudocholinesterase" or "butyrylcholinesterase" (BCHE). People with a homozygous BCHE mutation have delayed metabolism of succinylcholine, mivacurium, heroin, and cocaine.
In these patients, paralysis from succinylcholine can last for hours and you have to maintain them on mechanical ventilation until they can breath on their own
FA 2020, page 127:
Encapsulated bacteria are opsonized and then cleared by spleen. Asplenic patients have decreased opsonizing ability and an increased risk for severe infections.
They need vaccines to protect against Neisseria meningitidis, Streptococcus Pneumoniae, Haemophilus influenza
mnemonic: "No Spleen Here"
regardless I got this one wrong because of a 50/50 guess between strep and e. coli. I guess they wanted you to recognize that he was at risk for S. pneumonia sepsis and therefore needed to be vaccinated, whereas there's not much you can do to protect him from E. coli other than wash your hands lol
The way I approached the question was to consider what happens 1. When you grow from a baby to a child, and 2. when you grow from a teenager to an older adult. Whatever remained true between both of them was the right answer.
Right answer: The resting BP of a newborn is 65/40 (google), while that of a 1-month old is 95/60. The average adult is higher, with the American Heart Association citing (absurdly, IMO) that "normal" is <120/<80. Nevertheless, the trend is that BP increases as we age, whether we are newborns or old people.
Wrong answers: Development of coronary atherosclerosis: Perhaps due to the American diet it can be argued that the development of atherosclerosis is almost inevitable as you become an older adult. Certainly not true as a baby --> child.
Development of mitral stenosis: Similar reasoning as coronary atherosclerosis; you MAY develop it as an adult (not nearly as common as a buildup of atherosclerotic plaques), but sure, let's say that it can happen. Not true as a baby --> child.
Increased basal heart rate: The opposite is actually true. The basal heart rate of a newborn can easily exceed 150, and that's considered normal. As we age, this heart rate goes down.
Increased cardiac muscle mass: This one was the hardest to work through. It is true that as we age from a baby --> child our heart grows in size. But if we tweak our assumption from before with the American diet, and instead put our patient on a more moderate diet, realistically his heart shouldn't increase in size too much, at least to the point of cardiomegaly.
Increased compliance of arteries: As we become older adults, the compliance of arteries decreases and stiffness increases (careful not to confuse arteries with lungs, which actually do increase in compliance as we age!)
Reason why it's not E: While it's true that mycoplasma pneumoniae uses sterols for its cell membrane, it's the lack of a target for amoxicillin (peptidoglycan) that renders it ineffective. Classic test technique where they include a right answer but isn't the correct answer
The initial presentation looks like cancer: weight loss and progressive dyspnea over the course of months in a heavy smoker. Then, the question describes extra-pulmonary symptoms and a paraneoplastic syndrome.
More acutely, there is development of edema of the face and jugular venous distention. Because this is localized to upper body, we should think of a mechanical obstruction to venous flow as opposed to some cardiogenic reason. This is an extra-pulmonary symptom of lung cancer.
[ Superior Vena Cava Syndrome caused by the medial spreading of the tumor. Can be exacerbated in the physical exam by asking patient to raise both arms. ]
Finally, there is a single highlighted lab value -> hyponatremia. Small cell lung cancer can release inappropriate levels of antidiuretic hormone -> SIADH. ADH will retain water and decrease sodium concentration possibly leading to cerebral edema and seizures.
[ Syndrome of Inappropriate ADH (due to small cell carcinoma, a neuroendocrine tumor of the lung) decreases sodium concentration. Paraneoplastic syndrome. ]
In SketchyPath: SVC syndrome is the red balloon near the mediastinum ship and SIADH is the guy trying to carry the water cooler and getting water all over himself.
Phagocytes need to produce hydrogen peroxide from oxygen to be able to undergo the oxidative burst that will kill bacteria.
Hydrogen peroxide can come from:
Hydrogen peroxide can be degraded by catalase in catalase-positive organisms. Without hydrogen peroxide there is no creation of hydroxyl halide radicals and no destruction of the pathogen.
There are two catalase positive organisms in the answers: E. coli and S. aureus. We are more commonly in contact with S. aureus and it is the more common pathogen so that's the answer.
1-letter-abbreviation-accurate mnemonic for essential amino acids:
"MLK eradicated HIV FTW"
M = Methionine
L = Leucine
K = Lysine
H = Histidine
I = Isoleucine
V = Valine
F = Phenylalanine
T = Threonine
W = Tryptophan
P.S. It's MLK Day in the U.S. so perfect time to learn about Martin Luther King Jr.'s biochemistry/infectious disease side hustle.
the lack of Howell jolly bodies in asplenic patients is suggestive of accessory spleen