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€)

Retired NBME 22 Answers

nbme22/Block 1/Question#31 (reveal difficulty score)
A 60-year-old woman comes to the physician ...
Lung cancer ๐Ÿ” / ๐Ÿ“บ / ๐ŸŒณ / ๐Ÿ“–
tags:

 Login (or register) to see more


 +5  upvote downvote
submitted by โˆ—atstillisafraud(217)
get full access to all contentpick a username

Weight loss - think cancer Hyponatremia - SIADH from small cell lung cancer Edema + JVD - SVC syndrome

get full access to all contentpick a username
peridot  I was thinking lung cancer secreting SIADH, resulting in hyponatremia. But because the question asked specifically about the cause of the facial edema, I put hyponatremia (answer choice C). I was wondering how you guys were able to differentiate between C. hyponatremia and E. lung cancer? Thank you! +2
mannan  The first thing that crossed my mind was SVC syndrome from the cancer obstructing the R brachiocephalic vein preventing venous blood from returning to the heart (and staying in the facial area). Also I assume Hyponatremia would be equivalent to decreased body volume so there wouldn't be edema. FA Renal physiology section has a good chart on what happens during electrolyte imbalances (hypo and hyper) +2
mannan  @peridot +2
peridot  I was thinking that hyponatremia would be more loss of osmotic pressure --> edema, but I definitely see the argument for a mass that's simply blocking blood flow. Thank you! +1
jaramaiha  only thing affecting osmotic pressure is albumin, which would be more towards liver cirrhosis. The body will attempt to maintain a Na+ of 140 with various mechanisms, but doesn't contribute to osmotic pressure. +1



 +5  upvote downvote
submitted by โˆ—thirdaid(10)
get full access to all contentpick a username

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.

get full access to all contentpick a username
makinallkindzofgainz  I agree! Superior sulcus tumors is a lung carcinoma that occurs in the apex of the lung and can cause SVC syndrome. +2



 +1  upvote downvote
submitted by โˆ—agraham416(5)
get full access to all contentpick a username

am i the only dumb one who thought it was angioedema cause of the ACE inhibitor? totally neglected all other information.

get full access to all contentpick a username
dwdelva8  I did the same thing, but she had been on that ACE inhibitor for 15 years so I guess it would be strange for it to all of sudden cause symptoms +



 +0  upvote downvote
submitted by โˆ—ekraymer(1)
get full access to all contentpick a username

Was it wrong to see blood tinged sputum, and automatically assume its cancer? since none of the others would have caused blood tinged sputum?

get full access to all contentpick a username



Must-See Comments from nbme22

sacredazn on Unrearranged immunoglobulin gene
seagull on Decreased binding of RNA polymerase
seagull on Anticholinergic
mcl on Area labeled โ€˜Dโ€™
liverdietrying on Release of stored thyroid hormone from a ...
kernicterusthefrog on Displacement
keycompany on Negative nitrogen balance
joha961 on Displacement
imgdoc on Area labeled โ€˜Cโ€™ (Abducens nucleus, right)
alwaysanonymous on 25 mL/cm H2O
drdoom on 1 in 600
seagull on Glutamine
yotsubato on Phase variation
bubbles on Acute retroviral infection

search for anything NEW!