Axon
07-08-2005, 02:34 PM
1451
You know the famous Horner's syndrome and the symptoms of miosis, drooping eyelid on affected side, the sympathetic fiber involvement. But if Boards gave an MRI examination/pic of the brain showing a dissection of the right internal carotid artery in the upper cervical and petrous segments of this vessel. (OR a CT scan), could you point to the structure area lesioned of Horner's syndrome as sympathetic nerve fibers course along with this vessel?
(Please refer to a neuroanatomy atlas, I cannot put on on here, don't know how)....
1452
Ah, there is a RELATED dx. Board favorite that is a dx hitting the PULMONARY apex that also puts pressure on the sympathetic chain ganglion giving Horner's syn. What is the name of this? Could you identify it on a horizontal cross section?
a) Pancoast tumor...pls find it on your neuro atlas...PLEASE.
1453
There is another Board question that constitutes an ipsilateral third nerve paralysis with a contralateral hemiplegia. It is due to (possibly) a lesion in one half of the midbrain e.g. as a result of occlusion of the paramedian branches of the basilar artery. What is the dx. and can you pt to it on an atlas?
This is WEBER's syndrome, a lesion in the midbrain squeezing the CNIII. There could be paralysis of an upward gaze. If there is a localised lesion in the region of the red nucleus, then there IS paralysis of upward gaze.
1454
What is the DIFFERENCE in etiology of hypospadias and epispadias (holes in the penis)?
a) in hypospadias, you pee on your shoes and the URETHRAL FOLDS failed to close.
BUT, in episadias, there is a rupture of the cloacal membrane after complete separation of the genitourinary and GI tracts results in classic bladder exstrophy.
1455
You know EXACTLY how a picture of Kaposi's sarcoma looks like on the back, right? (Herpes-
1456
Boards LOVE giving you weird pharm questions about two or three drugs added to a neuromuscular junction (e.g.), at DIFFERENT times, and then naming one of the drugs. Do you know how to do this?
You see a radiograph of the lungs with a downward paralyzed diaphragm. Also, the pt. ate a cup of phenobarbital. Know this is a common cause(s) of ACUTE UNcompensated respiratory acidosis.
1457
If you give up passing Step 1, this WHOLE website and all my sore fingers and possible later Tommyk's Carpal Tunnel Syn. (hehehe), will be wasted. Keep on climbing, and then when you pass, write questions and help others. Share share share. Never stop.
BUT, if you feel yourself going crazy, or if your FAMILY needs you or God calls you elsewhere, then you HAVE to stop. But you will KNOW that in your heart you tried with everything you had. THAT is winning and passing...
By the way, give me a CLASSIC blood gas sample of a first time USMLE Step 1 test taker full of anxiety, breathing really fast:
pH: 7.5 (slightly up), PCO2: 22 (low, repiratory alkalosis), HCO3: 22 (at the low end of normal)...it takes a little more time more the kidneys to respond.
1458
Alright, now see a related case where there was a patient who kept vomiting after his USMLE Step 1 post party. What happens to his pH, PCO2, HCO3-?
HCl in stomach leaves (primary insult), so pH = 7.5, so PCO2 = 49 (you are retaining CO2), and HCO3-=35 (this is also higher). Recall that compensation moves in the same direction (does that make sense?).
Therefore, what is is condition?....
a) metabolic alkalosis with compensatory respiratory acidosis. KNOW that CONN'S syndrome (asked, asked, asked) also can show this ABG, as can the diuretic Lasix!!!!!!!!!!!!! Think about that for a second.
1459
Just know that usually Boards don't go too much into MIXED Arterial Blood Gas Stuff. They can be hard to solve, but a common one of mixed 1' metabolic acidosis and 1' respiratory alkalosis is aspirin overdose. Certain Gram negative bugs that release toxins can also be involved...
IN THESE CASES, just put a good guess that the pH will be
1) within the NORMAL range (recall, "mixed") and
2) both the PCO2 AND the HCO3- will be below normal..
1460
Boards LOVE cystic fibrosis. You will get at least one or many questions...
Pretend you have a pt. with cystic fibrosis 14 yrs old. What will his ABGs look like???
a) Ah! This will be CHRONIC respiratory acidosis with compensation THAT JUST CANNOT get back to normal pH. So, the pH will be slightly LOWER. And the PCO2 and HCO3- will be both ELEVATED. Don't forget this one. This is a Super Size Me question....
1461
Another popular one is DIARRHEA. So, you get traveler's diarrhea...a really bad case. THINK FAST, this one is easy. What is your ABG's?
a) You are losing "alkaline" stuff in your colon, so...
You will have more H+ than HCO3-, so pH is DOWN...makes sense eh?
There is always compensation so the PCO2 and the HCO3- will be lowered.
1462
You KNOW the Boards-loved Lesch Nyhan Syndrome. And I hope you KNOW there is hyperuricemia due to .......... HGPRTase def! But...what if they ask the inheritance pattern? What is it?
A) Pick Sex linked recessive among the answer choices. So mainly only boys...
1463
The urea cycle. Tell me, what IS the rate limiting enzyme? And the substrates and products please...
a) You better not forget...NH4+ FEEDS IN HERE with CO2 into carbamyl phosphate. The enzyme is carbamyl phosphate I.
1464
OK, next urea cycle step please...
With arrows a,b,c,d,e ,which substrate combines with carbamyl phosphate to form citruline? Does this step work in the cytoplasm?
a) ORNITHINE, and it combines in the mitochondria....NOT cytosol.
1465
Next phase, next craze, next wave, next step in urea cycle please.....
As CITRULINE is SHUTTLED out of the mitochondria, what substrate is formed as it combines with ASPARATE (can be fed in from the TCA cycle)? Enzyme too please.
a) ARGINOSUCCINATE via Arginosuccinate synthase (which happens to be rate limiting in the LIVER)
1466
Almost there...
Now in the urea cycle we have arginosuccinate. What TWO products does it split into?
a) ARGININE and FUMARATE (Fumarate fumes and rushes off into either gluconeogenesis or the TCA cycle)...VERY importante, as Goljan would say...hey, I rhymed again...Sorry, that wasn't that funny, Signed Tommy.
1467
At last...like a lover found again in Venice, we are at the last step of the urea cycle...
ARGININE now rids itself of WHAT and forms the starting ORNITHINE again?
A) UREA! via Arginase (oh, know that the kidney can also do the urea cycle)
1468
Oh yes...Kentucky Fried Chicken. A USA treasure to be sure! You have NOT had a meal in days and are now staring at a coupon for a bucket of golden triglycerides, long chained. After Lipase turns the stuff to Fatty Acids, what is your INSULIN level? You have to know all the pathways where INSULIN acts. YOU HAVE TO.
Second question, via what VITAMIN can the ODD CHAINED fatty acids be metabolized? (crucial)
a) Insulin is LOW and it DOES act at this step. Know it.
a2) Odd chained fatty acids must move through as Propionyl CoA, then as methylmalonyl CoA via VITAMIN B12 and methylmalonyl CoA mutase to form Succinyl CoA .... and you are back into the TCA cycle! (GREAT!). Lots of possible Board favorites here.
Vitamin B12...hmm..do pure vegetarians need supplements? Hmmm...without Vitamin B12 can you get a REVERSIBLE cause of dementia...confused with Alzheimer's? Is Vitamin B12 def. confused with folate defiency?
As Dr. Goljan said to me, "It has got Boards written all over it." He is a nice guy. I am nothing compared to him, but I'll try my best.
1469
Do you know G6Pase deficiency is often confused in answer choices with G6PD deficiency? Also, if you lack G6Pase (a key step in gluconeogenesis), what FAMOUS dx is present?
a) Von Gierke's disease! Very common. Very asked.
1470
Here is a juicy one...
This will combine concepts and tell yourself if you understand integrations...
True or False...Can you make VLDL from a Pentose Shunt product named Ribose 5 phosphate??? If so, HOW?
(Hard question...but...just try to guess first OK?)
a) This is an all time Boards favorite. Listen, Ribose 5 phosphate from the Pentose Shunt (which makes NADPH for use in Cholesterol Synthesis (and other stuff)) can be shuttled into G3P or Glyceraldehyde 3 phosphate (PART OF GLYCOLYSIS) which isomerizes to DHAP or Dihydroxyacetone phosphate. In an NADH driven reaction, you get GLYCEROL 3 PHOSPHATE, which WILL merge with cholesterol to form VLDL in the LIVER!
Wow! That was something... The key is that the metabolism of SUGARS like glucose CAN form triglycerides and VLDL. Many students think there is no link, but the Boards point out again and again that GLYCEROL 3 PHOSPHATE is a key link....as is DHAP.
SOOOOO.. That is why people go on low carb, higher fat diets! Boards love this kind of super information.
You know the famous Horner's syndrome and the symptoms of miosis, drooping eyelid on affected side, the sympathetic fiber involvement. But if Boards gave an MRI examination/pic of the brain showing a dissection of the right internal carotid artery in the upper cervical and petrous segments of this vessel. (OR a CT scan), could you point to the structure area lesioned of Horner's syndrome as sympathetic nerve fibers course along with this vessel?
(Please refer to a neuroanatomy atlas, I cannot put on on here, don't know how)....
1452
Ah, there is a RELATED dx. Board favorite that is a dx hitting the PULMONARY apex that also puts pressure on the sympathetic chain ganglion giving Horner's syn. What is the name of this? Could you identify it on a horizontal cross section?
a) Pancoast tumor...pls find it on your neuro atlas...PLEASE.
1453
There is another Board question that constitutes an ipsilateral third nerve paralysis with a contralateral hemiplegia. It is due to (possibly) a lesion in one half of the midbrain e.g. as a result of occlusion of the paramedian branches of the basilar artery. What is the dx. and can you pt to it on an atlas?
This is WEBER's syndrome, a lesion in the midbrain squeezing the CNIII. There could be paralysis of an upward gaze. If there is a localised lesion in the region of the red nucleus, then there IS paralysis of upward gaze.
1454
What is the DIFFERENCE in etiology of hypospadias and epispadias (holes in the penis)?
a) in hypospadias, you pee on your shoes and the URETHRAL FOLDS failed to close.
BUT, in episadias, there is a rupture of the cloacal membrane after complete separation of the genitourinary and GI tracts results in classic bladder exstrophy.
1455
You know EXACTLY how a picture of Kaposi's sarcoma looks like on the back, right? (Herpes-
1456
Boards LOVE giving you weird pharm questions about two or three drugs added to a neuromuscular junction (e.g.), at DIFFERENT times, and then naming one of the drugs. Do you know how to do this?
You see a radiograph of the lungs with a downward paralyzed diaphragm. Also, the pt. ate a cup of phenobarbital. Know this is a common cause(s) of ACUTE UNcompensated respiratory acidosis.
1457
If you give up passing Step 1, this WHOLE website and all my sore fingers and possible later Tommyk's Carpal Tunnel Syn. (hehehe), will be wasted. Keep on climbing, and then when you pass, write questions and help others. Share share share. Never stop.
BUT, if you feel yourself going crazy, or if your FAMILY needs you or God calls you elsewhere, then you HAVE to stop. But you will KNOW that in your heart you tried with everything you had. THAT is winning and passing...
By the way, give me a CLASSIC blood gas sample of a first time USMLE Step 1 test taker full of anxiety, breathing really fast:
pH: 7.5 (slightly up), PCO2: 22 (low, repiratory alkalosis), HCO3: 22 (at the low end of normal)...it takes a little more time more the kidneys to respond.
1458
Alright, now see a related case where there was a patient who kept vomiting after his USMLE Step 1 post party. What happens to his pH, PCO2, HCO3-?
HCl in stomach leaves (primary insult), so pH = 7.5, so PCO2 = 49 (you are retaining CO2), and HCO3-=35 (this is also higher). Recall that compensation moves in the same direction (does that make sense?).
Therefore, what is is condition?....
a) metabolic alkalosis with compensatory respiratory acidosis. KNOW that CONN'S syndrome (asked, asked, asked) also can show this ABG, as can the diuretic Lasix!!!!!!!!!!!!! Think about that for a second.
1459
Just know that usually Boards don't go too much into MIXED Arterial Blood Gas Stuff. They can be hard to solve, but a common one of mixed 1' metabolic acidosis and 1' respiratory alkalosis is aspirin overdose. Certain Gram negative bugs that release toxins can also be involved...
IN THESE CASES, just put a good guess that the pH will be
1) within the NORMAL range (recall, "mixed") and
2) both the PCO2 AND the HCO3- will be below normal..
1460
Boards LOVE cystic fibrosis. You will get at least one or many questions...
Pretend you have a pt. with cystic fibrosis 14 yrs old. What will his ABGs look like???
a) Ah! This will be CHRONIC respiratory acidosis with compensation THAT JUST CANNOT get back to normal pH. So, the pH will be slightly LOWER. And the PCO2 and HCO3- will be both ELEVATED. Don't forget this one. This is a Super Size Me question....
1461
Another popular one is DIARRHEA. So, you get traveler's diarrhea...a really bad case. THINK FAST, this one is easy. What is your ABG's?
a) You are losing "alkaline" stuff in your colon, so...
You will have more H+ than HCO3-, so pH is DOWN...makes sense eh?
There is always compensation so the PCO2 and the HCO3- will be lowered.
1462
You KNOW the Boards-loved Lesch Nyhan Syndrome. And I hope you KNOW there is hyperuricemia due to .......... HGPRTase def! But...what if they ask the inheritance pattern? What is it?
A) Pick Sex linked recessive among the answer choices. So mainly only boys...
1463
The urea cycle. Tell me, what IS the rate limiting enzyme? And the substrates and products please...
a) You better not forget...NH4+ FEEDS IN HERE with CO2 into carbamyl phosphate. The enzyme is carbamyl phosphate I.
1464
OK, next urea cycle step please...
With arrows a,b,c,d,e ,which substrate combines with carbamyl phosphate to form citruline? Does this step work in the cytoplasm?
a) ORNITHINE, and it combines in the mitochondria....NOT cytosol.
1465
Next phase, next craze, next wave, next step in urea cycle please.....
As CITRULINE is SHUTTLED out of the mitochondria, what substrate is formed as it combines with ASPARATE (can be fed in from the TCA cycle)? Enzyme too please.
a) ARGINOSUCCINATE via Arginosuccinate synthase (which happens to be rate limiting in the LIVER)
1466
Almost there...
Now in the urea cycle we have arginosuccinate. What TWO products does it split into?
a) ARGININE and FUMARATE (Fumarate fumes and rushes off into either gluconeogenesis or the TCA cycle)...VERY importante, as Goljan would say...hey, I rhymed again...Sorry, that wasn't that funny, Signed Tommy.
1467
At last...like a lover found again in Venice, we are at the last step of the urea cycle...
ARGININE now rids itself of WHAT and forms the starting ORNITHINE again?
A) UREA! via Arginase (oh, know that the kidney can also do the urea cycle)
1468
Oh yes...Kentucky Fried Chicken. A USA treasure to be sure! You have NOT had a meal in days and are now staring at a coupon for a bucket of golden triglycerides, long chained. After Lipase turns the stuff to Fatty Acids, what is your INSULIN level? You have to know all the pathways where INSULIN acts. YOU HAVE TO.
Second question, via what VITAMIN can the ODD CHAINED fatty acids be metabolized? (crucial)
a) Insulin is LOW and it DOES act at this step. Know it.
a2) Odd chained fatty acids must move through as Propionyl CoA, then as methylmalonyl CoA via VITAMIN B12 and methylmalonyl CoA mutase to form Succinyl CoA .... and you are back into the TCA cycle! (GREAT!). Lots of possible Board favorites here.
Vitamin B12...hmm..do pure vegetarians need supplements? Hmmm...without Vitamin B12 can you get a REVERSIBLE cause of dementia...confused with Alzheimer's? Is Vitamin B12 def. confused with folate defiency?
As Dr. Goljan said to me, "It has got Boards written all over it." He is a nice guy. I am nothing compared to him, but I'll try my best.
1469
Do you know G6Pase deficiency is often confused in answer choices with G6PD deficiency? Also, if you lack G6Pase (a key step in gluconeogenesis), what FAMOUS dx is present?
a) Von Gierke's disease! Very common. Very asked.
1470
Here is a juicy one...
This will combine concepts and tell yourself if you understand integrations...
True or False...Can you make VLDL from a Pentose Shunt product named Ribose 5 phosphate??? If so, HOW?
(Hard question...but...just try to guess first OK?)
a) This is an all time Boards favorite. Listen, Ribose 5 phosphate from the Pentose Shunt (which makes NADPH for use in Cholesterol Synthesis (and other stuff)) can be shuttled into G3P or Glyceraldehyde 3 phosphate (PART OF GLYCOLYSIS) which isomerizes to DHAP or Dihydroxyacetone phosphate. In an NADH driven reaction, you get GLYCEROL 3 PHOSPHATE, which WILL merge with cholesterol to form VLDL in the LIVER!
Wow! That was something... The key is that the metabolism of SUGARS like glucose CAN form triglycerides and VLDL. Many students think there is no link, but the Boards point out again and again that GLYCEROL 3 PHOSPHATE is a key link....as is DHAP.
SOOOOO.. That is why people go on low carb, higher fat diets! Boards love this kind of super information.