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Contributor score: 14


Comments ...

 +2  (nbme21#35)

The key to this question is that the patient is 4 months old and getting water.

Newborns should NOT be getting plain water until after 6 months of age because it can cause hyponatremia --> seizures


 +2  (nbme21#20)

Addition to Hungrybox's explanation:

Why it's not 47,XXY:

This would be referring to Klinefelter's, which is characterized by small, poorly functioning testicles.

However, question states "morphologic studies of a biopsy specimen of the testes show no abnormalities"

readit  More specifically, in Klinefelter's, you would see "hyaline seminiferous tubules/sertoli cells" on histology +2
pg32  Thanks! Where did you get the histologic description from? +1

 +0  (nbme21#25)

Why is is not pseudo aneurysm?

"Aortic pseudoaneurysms typically occur as a result of trauma +/- intervention, a considered subset of traumatic aortic injury in the majority of cases. They can be acute or chronic."

https://radiopaedia.org/articles/aortic-pseudoaneurysm?lang=us

readit  *same goes for saccular aneurysm, which also is usually 2/2 trauma +
samsam3711  In the question stem there is no indication of trauma so it would be hard to just assume that +
almondbreeze  see my comment above for marfan syndrome. might help +
drzed  This is because a pseudoaneurysm is between the media and adventitia, and is incited by trauma; a dissection is between the intima and the media and is a result of hypertension causing an intimal tear. The history points toward cocaine -> hypertension rather than penetrating trauma. +

 +3  (nbme21#36)

An anti-idiotypic antibody is an antibody which binds an antibody.

As an example, an anti-idiotypic antibody be helpful for treating a naiive B cell prior to activation, which express IgM and IgD on their surfaces. This is because the anti-idiopathic antibody can bind to the IgM/IgD antibody on the surface of a naiive B cell.

Multiple Myeloma cells, however, are made up of Plasma cells, which no longer express Ig's on their surface like naiive B cells do. Thus, there is no surface antibody [aka "membrane bound surface immunoglobulin"] for an anti-idiotypic antibody to bind to.

readit  Source: First aid Pg 105, 2019 edition +

 +0  (nbme21#16)

Why it is not MVP:

Full quotation from UpToDate: "Symptoms [... such as] various nonspecific symptoms such as palpitations, dyspnea, exercise intolerance, and dizziness have been attributed to MVP. However, symptoms are not reliable indicators of MVP. Furthermore, symptoms frequently seen in individuals with MVP have not been conclusively determined to be more prevalent than in the general population. As an example, in a study of 147 patients referred for echocardiography for suspected MVP, the presence of symptoms was not associated with MVP on echocardiography (found in 22 percent) [43]. (See "Mitral valve prolapse syndrome".)"





Subcomments ...

submitted by hayayah(1056),
unscramble the site ⋅ remove ads ⋅ become a member ($39/month)

therSct or naoidlit of teh xcriev nad nagaiv era tngros miiltsu orf iotxncoy eterosnci, deeitadm by alernu satphayw llecda the uognersF lfeexr.

Atl:ceri n/ocecucetw-imlswepirerhcenefotcnd.i/uowpgens:etcrssc/tfxis/.eor/

readit  This is also why ob-gyn's will massage the uterus (which is part of the birth canal) after delivery. It's to get the body to release oxytocin and cause the uterus to contract (to prevent postpartum hemorrhage) +5  
jennybones  Please why is estrogen not the answer, I thought estrogen would upregulate oxytocin receptors and increase oxytocin secretion? +1  
drzed  During pregnancy, oxytocin RECEPTORS are upregulated (by estrogen) as parturition approaches, but the ferugson reflex creates a positive feedback loop where the dilation of the cervix further releases more oxytocin. The inciting event that starts this feedback loop is the dilation of the cervix leading to a direct release of oxytocin, not the presence of more oxytocin receptors. +3  
bbr  To add, the positive feedback loop here is pretty elegant. Basically, it seems like the cervix doesnt want anything in it. When its stretched --> oxytocin --> contract uterus --> push baby --> more stretch at cervix---> more oxytocin (and forward). The positive feedback loop aspect is that oxytocin-based contractions cause more dilation of the cervix (as the baby moves into it!). +  


submitted by readit(14),

Addition to Hungrybox's explanation:

Why it's not 47,XXY:

This would be referring to Klinefelter's, which is characterized by small, poorly functioning testicles.

However, question states "morphologic studies of a biopsy specimen of the testes show no abnormalities"

readit  More specifically, in Klinefelter's, you would see "hyaline seminiferous tubules/sertoli cells" on histology +2  
pg32  Thanks! Where did you get the histologic description from? +1  


submitted by readit(14),

Why is is not pseudo aneurysm?

"Aortic pseudoaneurysms typically occur as a result of trauma +/- intervention, a considered subset of traumatic aortic injury in the majority of cases. They can be acute or chronic."

https://radiopaedia.org/articles/aortic-pseudoaneurysm?lang=us

readit  *same goes for saccular aneurysm, which also is usually 2/2 trauma +  
samsam3711  In the question stem there is no indication of trauma so it would be hard to just assume that +  
almondbreeze  see my comment above for marfan syndrome. might help +  
drzed  This is because a pseudoaneurysm is between the media and adventitia, and is incited by trauma; a dissection is between the intima and the media and is a result of hypertension causing an intimal tear. The history points toward cocaine -> hypertension rather than penetrating trauma. +  


submitted by readit(14),

An anti-idiotypic antibody is an antibody which binds an antibody.

As an example, an anti-idiotypic antibody be helpful for treating a naiive B cell prior to activation, which express IgM and IgD on their surfaces. This is because the anti-idiopathic antibody can bind to the IgM/IgD antibody on the surface of a naiive B cell.

Multiple Myeloma cells, however, are made up of Plasma cells, which no longer express Ig's on their surface like naiive B cells do. Thus, there is no surface antibody [aka "membrane bound surface immunoglobulin"] for an anti-idiotypic antibody to bind to.

readit  Source: First aid Pg 105, 2019 edition +