NBME 13 discussion

[ijn]

Are we allowed to talk about this topic? There's a NBME 12 discussion that has a lot of full questions posted but there are sticky posts that seem to say don't talk about the NBMEs. Thank you for any clarification!

---

Members don't see this ad.

 

[Habacuc319]

Deleted

 

[Habacuc319]

Okay, so I know this question has been covered and the general concensis is that "A" is correct. But WHY?
I know that this is a branchial cyst, which is located anterior to the SCM, but isn't the question asking where the cyst would open? If so, I thought it opened as a fistula postauricular or anterior to the parotid gland.

Can anyone explain this?

Fourth Branchial Cleft Cysts:
As with third branchial cleft cysts, these are extremely rare anomalies. Appearing as left-sided, anterior lesion at the lowest portion of the sternocleidomastoid muscle, these tracts pass, beginning at their insertion into the piriform fossa, down the neck lateral to the trachea and the recurrent laryngeal nerve to loop around the arch of the aorta. It then ascends into the neck slightly posterior to the common carotid artery where it later crosses over CN XII. It begins a second descent to open onto the skin at the lowest portion of the sternocleidomastoid. If there is a right sided fourth branchial cleft anomaly, it passes around the subclavian artery before it ascends into the neck. These are exceedingly rare lesions, with few demonstrable surgical procedures performed for this lesion.

 

[Habacuc319]

A 23 yo woman is brought to the emergency department 45 minutes after sustaining an injury to her right shoulder when she was forceful thrown into a swimming pool. The patient is holding her right arm in external rotation. There is an area of tenderness and absent sensation over the lateral aspect of her forearm, immediately after reduction of the glenohumeral joint, she is unable to flex the elbow against gravity. Which of the following structures is most likely injury in this patient?
a. Axillary Nerve: Post cord Extensors
b. Musculocutaneos Nerve IS IT RIGHT?
c. Posterior cord of the brachial plexus
d. Radial Nerve: Post cord, Extensors
e. Thoracodorsal nerve

 

[ZGX]

A 23 yo woman is brought to the emergency department 45 minutes after sustaining an injury to her right shoulder when she was forceful thrown into a swimming pool. The patient is holding her right arm in external rotation. There is an area of tenderness and absent sensation over the lateral aspect of her forearm, immediately after reduction of the glenohumeral joint, she is unable to flex the elbow against gravity. Which of the following structures is most likely injury in this patient?
a. Axillary Nerve: Post cord Extensors
b. Musculocutaneos Nerve IS IT RIGHT?
c. Posterior cord of the brachial plexus
d. Radial Nerve: Post cord, Extensors
e. Thoracodorsal nerve

B. Musculocutaneous is used to flex the biceps, from lateral part of brachial plexus

 

[Habacuc319]

B. Musculocutaneous is used to flex the biceps, from lateral part of brachial plexus

Thanks!!

 

[Habacuc319]

31 yo woman comes to the ER with difficult breathing and muscle weakness for 10 minutes. She has a 3 year history of myasthenia gravis treated with neostigmine. The husband reports that she double her doses 2 days ago but her weakness increase since then. Which of the following event is most likely responsible for the increase of the weakness of this patient?
a. Autoimnune hyper activation of nicotinic receptors????
b. autoimmune inactivation of muscarinic receptors
c. desensitization of nicotinic receptors ????
d. excessive degradation of acetylcholine
e. hyper sensitization of muscarinic receptors
f. insufficient release of acetylcholine

 

[ZGX]

31 yo woman comes to the ER with difficult breathing and muscle weakness for 10 minutes. She has a 3 year history of myasthenia gravis treated with neostigmine. The husband reports that she double her doses 2 days ago but her weakness increase since then. Which of the following event is most likely responsible for the increase of the weakness of this patient?
a. Autoimnune hyper activation of nicotinic receptors????
b. autoimmune inactivation of muscarinic receptors
c. desensitization of nicotinic receptors ????
d. excessive degradation of acetylcholine
e. hyper sensitization of muscarinic receptors
f. insufficient release of acetylcholine

The answer is (C)
receptors got desensitized

 

[Habacuc319]

The answer is (C)
receptors got desensitized

Thanks!!

 

[phd89]

A 23 year old women with type 1 Diabetes Mellitus is brought to the physician for a follow up examination. She has a H/O of recurrent yeast infections. genetic analysis shows a def of myeloperoxidase. Which of the following is her cause of infections.

a.dec oxygen consumption after phagocytosis
b. defective neutrophil degranulation
c. defective production of prostaglandins
d.Inability to produce hydrogen peroxide
e. in ability to produce hyrodyl halide radicals

I chose D which was wrong can someone please expalin to me the correct answer I don't get it????????????

 

[Habacuc319]

A 23 year old women with type 1 Diabetes Mellitus is brought to the physician for a follow up examination. She has a H/O of recurrent yeast infections. genetic analysis shows a def of myeloperoxidase. Which of the following is her cause of infections.

a.dec oxygen consumption after phagocytosis
b. defective neutrophil degranulation
c. defective production of prostaglandins
d.Inability to produce hydrogen peroxide
e. in ability to produce hyrodyl halide radicals

I chose D which was wrong can someone please expalin to me the correct answer I don't get it????????????

I would say E because I found this:
Myeloperoxidase deficiency is a common genetic disorder featuring deficiency, either in quantity or function, of myeloperoxidase, an enzyme found in certain phagocytic immune cells, especially polymorphonuclear leukocytes.
It can appear similar to chronic granulomatous disease on some screening tests.
Although MPO deficiency classically presents with immune deficiency (especially candida albicans infections), the majority of individuals with MPO deficiency show no signs of immunodeficiency.
The lack of severe symptoms suggest that role of myeloperoxidase in the immune response must be redundant to other mechanisms of intracellular killing of phagocytosed bacteria.
Patients with MPO deficiency have a respiratory burst with a normal nitro blue tetrazolium (NBT) test because they still have NADPH oxidase activity, but do not form bleach due to their lack of myeloperoxidase activity. This is in contrast to chronic granulomatous disease in which the NBT test is 'negative' due to the lack of NADPH oxidase activity (positive test result means neutrophils turn blue, negative means nitroblue tetrazolium remains yellow).
Myeloperoxidase Deficiency:
Create dec HOCl- (Hydroxy-halide radicals) from H2O2 due to dec Myeloperoxidase
Dec Respiratory Burst to use against bacteria
Effects similar to Chronic Granulomatous Disease (CGD)

What do you think?

 

[phd89]

yeah your probably right but I never came across it like that hydroxyl halide radical, i guess they really wanted to stump you

 

[phd89]

made it a little shorter


A 12 year old girl is bought to the emergency dept and has a sickle cell crisis what is the underlying reason for her symptoms?

a. abnormal folding of the hemoglobin molecule causedby inc PC02
b. abnormal hydrogen bonding in the hemoglobin caused by amino acid substitution on the alpha chain
c. dec oxygen affinity caused by an amino acid subsitution in the hemoglobin alpha chain
d. erythrocyte fragility caused by an anmino acid subsitution in glycoprotiens on the cell surface
e. polymerization of hemoglobin with hypoxic conditions due to amino acid substitution in the B chain

 

[Habacuc319]

made it a little shorter


A 12 year old girl is bought to the emergency dept and has a sickle cell crisis what is the underlying reason for her symptoms?

a. abnormal folding of the hemoglobin molecule causedby inc PC02
b. abnormal hydrogen bonding in the hemoglobin caused by amino acid substitution on the alpha chain
c. dec oxygen affinity caused by an amino acid subsitution in the hemoglobin alpha chain
d. erythrocyte fragility caused by an anmino acid subsitution in glycoprotiens on the cell surface
e. polymerization of hemoglobin with hypoxic conditions due to amino acid substitution in the B chain

Answer (for sure) E ) Look up FA 012, page 384

 

[rohit39]

The answer is "variability in outcome assessment." You're not measuring lab values or some other objective form of evaluation. You're measuring a subjective "do you feel better" after giving an intervention. People will think they get less colds because that's what they've been told by the supplement industry and the media.

Actually to elaborate on your answer, its more about the fact that the outcome events are "reported by the parents", so that's where the bias comes my opinion.

Ideally there should be a physician who takes history and examines a child to determine presence of a cold or not.

 

[Sitruc]

A 38-year-old woman is brought to the emergency department after being found lying on the sidewalk. She is conscious but says she is too weak to stand. Physical examination shows a red, swollen, tender tongue; angular stomatitis; and spoon-shaped nails. Hemoglobin and mean corpuscular volume are decreased. Which of the following is the most likely diagnosis?

The small MCV points to Iron deficiency, right?
But shouldn't Iron deficiency have a pale tongue, not a red one?

 

[Phloston]

A 38-year-old woman is brought to the emergency department after being found lying on the sidewalk. She is conscious but says she is too weak to stand. Physical examination shows a red, swollen, tender tongue; angular stomatitis; and spoon-shaped nails. Hemoglobin and mean corpuscular volume are decreased. Which of the following is the most likely diagnosis?

The small MCV points to Iron deficiency, right?
But shouldn't Iron deficiency have a pale tongue, not a red one?

Iron deficiency anaemia + oesophageal webs + glossitis/stomatitis = Plummer-Vinson syndrome

 

[Ricegrad05]

I didn't sign up for expanded feedback so I don't know if I got this wrong.

Q: Women with MS like symptoms and minor findings on MRI who also had a recent visit from in-laws (?stress).

Was correct answer MS or conversion disorder?

 

[wrx981]

I didn't sign up for expanded feedback so I don't know if I got this wrong.

Q: Women with MS like symptoms and minor findings on MRI who also had a recent visit from in-laws (?stress).

Was correct answer MS or conversion disorder?

If I remember correctly you are correct, b/c I believe the stem made mention of incontinence and multiple plaques on MRI. Believe she also had difficulty with vision.

 

[jadealer]

A 23 year old woman comes to the physician because of t day hx of chills, nausea, and vomiting. She also has a 4 day history of flank pain, urinary frequency, and pain with urination. Her temp is 102 F pulse is 125/min, and BP 90/60. Physical examination shows right costovertebral angle tenderness. UA shows 25 WBC/hpf. A urine sample grows pink colonies on lactose-MAcConkey agar, produces a characteristic green sheen on eosin-methylene blue agar and is indole +. The production of which of the following by the bacterium aids in the virulence of the causal organism in this patient?

A- adhesins
B- antihemolytic factors
C- pyrogenic exotoxic
D- teichoic acid in the cell wall
E - thick peptidoglycan Layer

Is the answer to this C?? cause the organism is e. coli right?

 

[Jamiu22]

A 23 year old woman comes to the physician because of t day hx of chills, nausea, and vomiting. She also has a 4 day history of flank pain, urinary frequency, and pain with urination. Her temp is 102 F pulse is 125/min, and BP 90/60. Physical examination shows right costovertebral angle tenderness. UA shows 25 WBC/hpf. A urine sample grows pink colonies on lactose-MAcConkey agar, produces a characteristic green sheen on eosin-methylene blue agar and is indole +. The production of which of the following by the bacterium aids in the virulence of the causal organism in this patient?

A- adhesins
B- antihemolytic factors
C- pyrogenic exotoxic
D- teichoic acid in the cell wall
E - thick peptidoglycan Layer

Is the answer to this C?? cause the organism is e. coli right?

you are correct about the bacteria: the patient has a uti.. the main viruilence factor of e.coli in the context of this question is actually the pili.... it let's them adhere to the urethral wall an not be washed out during urination.. so I'm guessing that it's A-Adhesins..

 

[Phloston]

A 23 year old woman comes to the physician because of t day hx of chills, nausea, and vomiting. She also has a 4 day history of flank pain, urinary frequency, and pain with urination. Her temp is 102 F pulse is 125/min, and BP 90/60. Physical examination shows right costovertebral angle tenderness. UA shows 25 WBC/hpf. A urine sample grows pink colonies on lactose-MAcConkey agar, produces a characteristic green sheen on eosin-methylene blue agar and is indole +. The production of which of the following by the bacterium aids in the virulence of the causal organism in this patient?

A- adhesins
B- antihemolytic factors
C- pyrogenic exotoxic
D- teichoic acid in the cell wall
E - thick peptidoglycan Layer

Is the answer to this C?? cause the organism is e. coli right?

you are correct about the bacteria: the patient has a uti.. the main viruilence factor of e.coli in the context of this question is actually the pili.... it let's them adhere to the urethral wall an not be washed out during urination.. so I'm guessing that it's A-Adhesins..

Choice A is right. Kaplan has even asked in one of its questions about the specific type of pili involved in E. coli-induced UTIs, and it's P-pilus.

 

[Jiayue]

Read through all the posts in this thread, don't think following question has been asked. Really appreciate if anyone can explain.

40y woman with family history of muscle weakness. Her symptoms are not severe, but her four children have profound muscle weakness and fatigue. Pedigree shows mutations for 50% of the mother's mitochondria DNA and 100% each of the children's. Asks for the genetic principle that explains this. Choices are anticipation, genetic drift, heteroplasmy, impringting, psudodominant inheritance.

I got psudodominant inheritance which is wrong. Now I think the answer might be heteroplamy. Don't know why though

 

[CDI]

Read through all the posts in this thread, don't think following question has been asked. Really appreciate if anyone can explain.

40y woman with family history of muscle weakness. Her symptoms are not severe, but her four children have profound muscle weakness and fatigue. Pedigree shows mutations for 50% of the mother's mitochondria DNA and 100% each of the children's. Asks for the genetic principle that explains this. Choices are anticipation, genetic drift, heteroplasmy, impringting, psudodominant inheritance.

I got psudodominant inheritance which is wrong. Now I think the answer might be heteroplamy. Don't know why though

It's one of the "muscle fibers" diseases. (The UW question mentioned the types specifically - I'll have to check my notes). Those are all mitochondrial DNA inheritance. Heteroplasmy is presence of both normal and mutant mtDNA (which the mother has). And since mitochondrial DNA is passed on from the mother (sperm loses its mitochondria in the tail) this would fall into heteroplasmy.

 

[jpudge12]

........

 

[CDI]

What is the mode of inheritance of Acute intermittent porphyria?

thanks in advance

http://bit.ly/Y0Gdgk

 

[Phloston]

What is the mode of inheritance of Acute intermittent porphyria?

thanks in advance

The porphyrias are AD.

Sideroblastic anaemia, in contrast, is XR.

 

[kaam2724]

It was picture of osteoporosis and the answer is IL-1 and monoclonal was wrong.

 

[Jonari]

anybody miss around 23 questions on this? missed 38...but looking at my silly mistakes, 15 of those questions could've been avoided...just curious...but what would the score have been had I missed only 23 questions...

 

[medpack87]

I missed 35.

 

[Jonari]

I missed 35.

silly mistakes? i made 15 stupid potato mistakes i shouldnt have missed

was able to get hasimoto's and intrinsic factor...but couldn't get some easy pharm questions

hated all the perineum anatomy questions

 

[Jonari]

i always get questions like these wrong...even the ones associated with the catheter when it asks how do you eliminate the risk of infection in the patient...any tips?

2nd question:

ok, so 1 is not in the interval, so that means there is a statistical difference, correct? 1 - 0.3 = 0.7 = 70% decreased risk of getting gastric cancer if a patient is taking selenium, so is the answer D?

i guess i was ove rthinking this but is it just 1 - beta = power, so X > Y

what is the diagnosis for the neuro condition? had no idea...so had to guess. i knew it wasn't A or D.

what about these two behavioral questions. for the first, isn't it our job as a physician to ease and make the patient feel comfortable. im guessing its wrong, because of possible risk of addiction?

 

[Jonari]

lastly, how can i improve on these anatomy questions? i know FA repro has a table at the bottom of the page, but it still didn't help me score these points. in add'n to the thoracocentesis question...

 

[MedicineMike]

The thoracocentesis is very similar to a UWorld question. You always go above the rib as to not damage the neuro vascular bundle. Since it is below rib 7, you want to go above a rib that is below 7, so go above 9.

 

[MedicineMike]

Also, removing ovary would require you to legate the ovarian artery and vein. Think about what would cause flank pain and discomfort around your kidney after removing an ovary. The only answer choice that fits would be the ureter. Also, the ureter runs right under and in close proximity to the ovarian vessels

 

[SLC]

i always get questions like these wrong...even the ones associated with the catheter when it asks how do you eliminate the risk of infection in the patient...any tips?

Hand washing, it's always hand washing when there's not some mention of invasive bedside procedure (and even then it still often is). This is a huge issue at every hospital in the country. Answer is D.

2nd question...:

You are correct here...Answer is D. If relative risk is less than 1, then risk of even is lower in study group than in control group. If it's higher than 1, then risk is higher in study group.

i guess i was ove rthinking this but is it just 1 - beta = power, so X > Y

Y>X 1-beta=power. So beta = 1.8 for X and 1.9 for Y. Beta measures likelihood of type II error. Answer is B

what is the diagnosis for the neuro condition? had no idea...so had to guess. i knew it wasn't A or D.

Wonky question, and I'm no good at neuro, but I'm still fairly confident that's a vascular malformation. Answer is E

what about these two behavioral questions. for the first, isn't it our job as a physician to ease and make the patient feel comfortable. im guessing its wrong, because of possible risk of addiction?

Reassess patient after his pain has been controlled (i.e. he probably won't hurt so bad that he thinks he wants to die at that point) Answer is C

And for the guy being consented for the pacemaker, if full disclosure of risks and follow up is not provided, then that's not gaining informed consent. Answer is B

 

[SLC]

lastly, how can i improve on these anatomy questions? i know FA repro has a table at the bottom of the page, but it still didn't help me score these points. in add'n to the thoracocentesis question...

As medicine mike explained above, always insert catheters and chest tubes etc at the superior border of a rib to avoid the intercostal nerve, artery, and vein. I'd go for D.

Answer is F here Though there are two uterosacral ligaments, I think this is still the answer they are looking for. They originate near the cervico-uterine junction, and insert onto the sacrum just posterior to the origin.

I'd go with ureter on this, she's probably got a bit of hydronephrosis.

 

[Jonari]

SLC, thanks for the post, but it seems like post 348 says that for the power question it's A.

 

[SLC]

Read through all the posts in this thread, don't think following question has been asked. Really appreciate if anyone can explain.

40y woman with family history of muscle weakness. Her symptoms are not severe, but her four children have profound muscle weakness and fatigue. Pedigree shows mutations for 50% of the mother's mitochondria DNA and 100% each of the children's. Asks for the genetic principle that explains this. Choices are anticipation, genetic drift, heteroplasmy, impringting, psudodominant inheritance.

I got psudodominant inheritance which is wrong. Now I think the answer might be heteroplamy. Don't know why though

Heteroplasmy. The basis of expression variability in Mitochondrial Disease.

Anytime you have a question with "ragged red fibers" or anything similar in the description, along with either MSK or neuro (or both) symptoms you should be think Mitochondrial Disease, Inherited from the mother only, and heteroplasmy.

 

[SLC]

SLC, thanks for the post, but it seems like post 348 says that for the power question it's A.

Damn, well it's late here in the Empire, and I made an calculation mistake. Yes A is correct.

Beta for X is 0.2
Beta for Y is 0.1

X>Y

 

[Jonari]

Question 15, on block #3 asking about:

"3 yr old girl is found to have a grade 4/6, loud, harsh, high-pitched holosystolic murmur that radiates over precordium and a palpable thrill at left sternal border? Which of the following is most likely defect?

I still don't see why the answer isn't tricuspid regurg? most are saying the answer is VSD...is this just testing our knowledge to see which is the more common valvular defects in a young child?

 

[Jonari]

crap, didn't know murine means related to mice...missed the question about bevacizumab.

 

[RIPSanto]

How about the question that had two gross (R/L) hemispheres with various structures labeled. The vignette was regarding a lady with LEFT sided sensory loss in her hand. When I did this question I honestly felt like there was not a correct answer. I assumed that since the sensory deficit was on the left the lesion had to be on the right hemisphere, so I ruled out the entire Left brain. However, on the Right brain there wasn't anywhere that really matched up with the primary sensory cortex that would get the hand (based on the homonculus). I ended up picking C, which I think is more anterior and representing the primary MOTOR cortex to the hand.

Anyway, if they wanted one of the sections that was on the right brain, that just seems wrong. It is obvious from the section that it was a right brain so how can the lesion be there? Anyone have any thoughts here

 

[RIPSanto]

Question 15, on block #3 asking about:

"3 yr old girl is found to have a grade 4/6, loud, harsh, high-pitched holosystolic murmur that radiates over precordium and a palpable thrill at left sternal border? Which of the following is most likely defect?

I still don't see why the answer isn't tricuspid regurg? most are saying the answer is VSD...is this just testing our knowledge to see which is the more common valvular defects in a young child?

Yeah that is a good point. To be honest, I never even considered TR, and had I thought about it I probably would have had a hard time deciding between the two. When I see a young person with a murmor, I instantly start thinking ASD, VSD, PDA or something congenital.

FWIW, FA says that TR is caused by RV dilation, rheumatic fever, and infective endocarditis. None of which are mentioned in the stem. VSD on the other hand is a common congenital problem that can present really any time in childhood depending on how severe it is.

 

[addo]

anybody miss around 23 questions on this? missed 38...but looking at my silly mistakes, 15 of those questions could've been avoided...just curious...but what would the score have been had I missed only 23 questions...

missed 20... good for a 620 or 250. Missed 5 easy easy questions

 

[Pinkleton]

I think there was a question that basically told you the patient had myasthenia gravis and then asked what lab test would be positive. I put check for antibodies against the ACh receptor but was not comfortable picking it because elevated ESR was also a choice. For one, if you could use that lab test then why do we do the edrophonium test. Also, wouldn't ESR be elevated because MG is an inflammatory process (type 2 HS)?

 

[medpack87]

I think there was a question that basically told you the patient had myasthenia gravis and then asked what lab test would be positive. I put check for antibodies against the ACh receptor but was not comfortable picking it because elevated ESR was also a choice. For one, if you could use that lab test then why do we do the edrophonium test. Also, wouldn't ESR be elevated because MG is an inflammatory process (type 2 HS)?

I dont remember the answer choices well. Was edrophonium one of them? If that was among the answer choices, that was probably the right answer.

ESR would only tell you that she has some inflammatory process, it could be myasthenia, a paraneoplasic syndrome, polymyositis, among others.

 

[SLC]

I think there was a question that basically told you the patient had myasthenia gravis and then asked what lab test would be positive. I put check for antibodies against the ACh receptor but was not comfortable picking it because elevated ESR was also a choice. For one, if you could use that lab test then why do we do the edrophonium test. Also, wouldn't ESR be elevated because MG is an inflammatory process (type 2 HS)?

Myasthenia Gravis is defined by auto-antibodies against the ACh receptor, that seems like a slam dunk question to me. But I'm not aware if there is even a lab to check for that so maybe it's wrong because of that?

Edit: Epocrates says there is! (Serum Anti-AchR analysis)

Unless the patient didn't really have MG...

 

[Pinkleton]

That was my reasoning at first as well, that there is not a way to test for the antibody. But I went ahead and picked it anyway. ESR would definitely have been a better answer choice than a nonexistent test, which was why I was thinking about picking it

 

[addo]

ESR is very non specific, I doubt there will ever be an answer where ESR is diagnostic for anything, with the exception being temporal arteritis and polymyalgia rheumatica which are actually closely associated.

 

[Pinkleton]

Gah I'm totally overthinking these. Gotta get out of that UWorld frame of mind