Measuring size of OPA and NPA mnemonic

The oropharyngeal and nasopharyngeal airway are temporary airway devices. You need to select an appropriate size before inserting the airway.

Radiology series #1 X-rays 1.0

Hello awesomites!

Today I am starting a new series of posts on radiology. Here I will be mostly dealing with the theory and technical part of radiology which as an undergraduate student we rarely read. Starting off with x-rays in this post and CT, USG, MRI to follow in the consecutive ones!

X-rays

A little bit of history,

X-rays were discovered by W. C. Roentgen in Germany on 8^th nov 1895 and for which he received a Nobel Prize in 1901.

First let us know a few technical terms, collectively known as the ‘exposure factors: 

     1) kVP: kilovolt peak

     It determines the penetration of the x-ray beam through the body. High kVP implies more penetration of the body tissues

     2) mAS: milliampere second

     It determines the amount of blackening of the film. A high mAS will cause more blackening of the film for the same amount of x-rays hitting it.

      3) Contrast: It is the contrast shadow that is produced on the film i.e. white for bone and black for soft tissues. It is influenced mainly by the penetration of the x-rays i.e. the kVP and partly by mAS.

A low kVP (low penetration) means high contrast.

Contrast is proportional to 1/kVP

But,

A low mAS (less blackening) means low contrast.

Contrast is directly proportional to mAS

Let us take up an example,

In obese and heavily built patients, more penetrance is needed so we need to increase the kVP but if we do so by increasing the kVP we are reducing the contrast which is not good.

So to achieve both high contrast and good penetrance, kVP is increased as well as mAS is increased.Increased kVP will take care of the required penetrance while high mAS will ensure good contrast.

The general protocol to increase the contrast is first by reducing the kVP and then if necessary increasing the mAS to desired levels.

That’s all for now, more about the actual working of the x-ray machine and different settings in the next post. Hope you liked it !

Until then,

Keep calm and keep studying

Stay awesome!

-          Ashish G. Gokhale

Facebook: Penicillin

This is answer to one of the questions on chemotherapy posted on medicowesome facebook.
Question is as follow.

Which of the following statement about penicillin G is true

1) It is commonly administered orally.
2) It has a broad spectrum of antibacterial activity.
3) It can be used for the treatment of rate bite fever.
4) Concomitant probenecid decreases it's duration of action.

Answer is 3- It can be used for the treatment of rate bite fever.

Explanation:

Penicillins belongs to the group of Beta-Lactam antibiotics.
These group includes compounds having Beta-Lactam ring in their structure. Apart from penicillin beta-lactam antibiotic group includes following classes:-

Cephalosporins
Monobactams
Carbapenems

You can remember them as
"See PCM"

C(See)-Cephalosporins
P-Penicillin
C-Carbapenems
M-Monobactams

Now, coming to Penicillin G

1) It is not effective orally because of breakdown by acid in the stomach.
Hence, a seprate class of penicillins are introduced which are acid resistant.

A very famous mnemonic is: VODKA
V= Penicillin V
O= Oxacillin
D= Dicloxacillin
K= Cloxacillin
A= Ampicillin and Amoxycillin

2) It has short duration of action due to rapid excretion from kidney. To overcome this we do one of the two things
a) Benzathine and procaine groups are added to penicillin G
Benzathine is longest acting penicillin G
b) Probenecid can be administered with penicillins. It inhibits the tubular secretions.

3) Penicillin G has narrow spectrum of antibacterial activity. Several new penicillins with extended spectrum are added. They are as follow.

CAT Action MAP.
C= Carbenicillin
A= Ampicillin
T= Ticarcillin
A= Amoxicillin
M= Mezlocillin
A= Azlocillin
P= Piperacillin

4) It is first choice of drug for:-

Mnemonic: SMARt GV loves yogurt.
S=Syphilis
M=Meningococcal meningitis
A=Actinomycosis
R=Rat bite fever
t
G=Group A and B streptococcal infections
V=Viridian streptococcal endocarditis
L=Leptospirosis
Y=Yaws

Some important points to remember:

1) All drugs having beta lactamse ring are bacteriocidal.
2) They act on PBP(Penicillin binding proteins) present on cell membrane.
3) MRSA occur due to alterations in PBPs, hence no beta lactams are useful against it.

Facebook: TDK, CDK, PAE.

So, this post is about our chemotherapy question posted on facebook page.

Question is as follow

Time dependant killing and prolonged post-antibiotic effect is seen with:

1) Fluoroquinolones.
2) Beta-Lactam antibiotics.
3) Clindamycin.
4) Erythromycin.

Answer is 2- Beta lactam antibiotics

Okay, so let's get started.

Today we will learn about three simple and basic concepts of the chemotherapy.

1) Concentration dependent killing:
The killing effect of a drug is high when ratio of peak concentration to MIC(Minimum inhibitory concentration) is more.

Simplified version:
Suppose drug called as "A" kills a particular bacteria.
Now I am going to put 2 units of this drug in a medium containing that bacteria for 10 minutes. After 10 minutes when I check the medium I still find the living bacteria present. I wait for another 10 minutes. After total 20 minutes I recheck it - I still find living bacteria!

Now, I change the concentration of the drug "A" to 4 units but keeping the time same i.e. 10 minutes. Now, when I check the medium for bacteria after 10 minutes  I find dead bacteria. This means that antibiotic dose of 4 units is needed minimum for killing the bacteria irrespective of the time.

In a nutshell: These drugs need one large dose for their action rather than  multiple small doses

Drugs having CDK:
Mnemonics: CAFe

C=CDK
A= Aminoglycosides
F=Fluoroquinolones

2) Time dependant killing( TDK) :
This means the antimicrobial action depends on the length of time the concentration remains above MIC.

Simplified version:
Let's take the same example.

Now, "2 units" of drug A is kept for 10 minutes in a medium containing particular bacteria. After 10 minutes I check the medium and I find living bacteria. I add 2 units more and I wait for another 10 minutes like I did previously. But this time after total of 20 minutes I find dead bacteria!

Now, I again do this experiment but this time with 4 units of drug A.
I wait for 10 minutes
Result: Living bacteria
I wait for another 10 minutes( Total =20 minutes) without adding any further dose.
Result: Dead bacteria.

In a nutshell: In TDK, multiple doses are preferred over single dose!

Drugs having TDK:
Mnemonics : T.V. Box.

T= TDK
V=Vancomycin
B= Beta-Lactams

3) Post antibiotic effect (PAE):

After an organism is exposed to antibiotic, it's growth stops. When it is put in antibiotic free medium, the growth resume after sometime.
This is called as PAE.

PAE is seen when antibiotic concentration is below MIC.

Drugs showing PAE:
Most of the antimicrobials have long PAE against gram positive bacteria.

Drugs showing PAE against gram negative bacteria:
Mnemonic- CPD(cephalo-pelvic disproportion) nurse.

C= Carbapenems
P= Protein synthesis affecting drugs(Aminoglycosides, chloramphenicol, tetracyclines)
D= DNA synthesis affecting drug ( Quinolones, rifampicin)

N= Negative bacteria

Points to remember:

1) Rifampicin prolongs the PAE of isoniazid.
2) Macrolides and clindamycin also possess time dependent activity. However they are static drugs so we cannot use TDK term for them.

Crystal Induced Kidney Injury

Drugs responsible :

SAME Piiiiii (Peeeeee)

Sulfonamides

Acyclovir

Methotrexate

Ethylene glycol

Protease inhibitors

MCQ mnemonics series: Mnemonic for a condition causing lower abdominal pain

A 60-year-old male is admitted with a two day history of lower abdominal pain and marked vomiting. On examination he has abdominal swelling, guarding and numerous audible bowel sounds. What is the diagnosis?

1) Gallstone ileus
2) Ischaemic colitis
3) Large bowel obstruction
4) Sigmoid volvulus

Answer given below:

Facebook: ANS and dilated pupil.

So, this post is regarding answer of our recent pharmacology question posted on facebook medicowesome group. If you still are not following it, please follow for latest updates and interesting questions.

Q) What is the probable diagnosis in a patient with a dilated pupil not responsive in 1% pilocarpine? (AIIMS 2011 Nov)

1) Diabetic 3rd nerve palsy.
2) Adie's tonic pupil.
3) Uncal herniation.
4) Pharmacological block.

Answer is option 4- Pharmacological block.

Let's start with the basics of the ANS to understand the question.

First, imagine an eye with simplest of the structures.
A central area called as pupil. Surrounded by group of muscles called as "constrictor pupillae muscles" which obviously helps in constriction (miosis) of the pupil as their name suggests. They are  further surrounded by "radial muscles" which causes dilation (and mydriasis) of the eye.

Now, each of these muscles will have receptors on them. Receptors need to be stimulated for their respective actions, right? - Yes!
Now, remember - M3 receptors are present on constrictor muscles and Alpha-1 receptors are present on radial muscles.

Now, you must be thinking why I am goofing around with such simple basic concepts?!
Hold on, question may contain confusing options but you already know the answer. Atleast now you do know!
(Read question again and come back!)

Pilocarpine is selective M3 agonist. Stimulation of M3 receptors will lead to miosis.

In pharmacological block, drugs like atropine block the muscarinic receptors present on the pupil. As, the receptors cannot work, pilocarpine cannot produce miosis.

( You really don't need to know all the things to answer MCQs. Sometimes basics are enough!)

Now, let us know more about other options.

1) Diabetic 3rd nerve palsy: Occulomotor motor nerve supplies constrictor puplillae So, palsy of 3rd nerve will cause mydriasis but does it cause any damage to receptors? - No.
So, pilocarpine will respond and thus miosis will occur!

2) Adie's tonic pupil: It manifests as denervation supersenstiviy. Normal pupil responds to 1% pilocarpine but not to dilated solution like 0.05-0.1%. However, in Adie's pupil due to supersenstiviy of receptors, even this diluted solution may results in constriction.

3) Uncal herniation: Pressure on 3rd nerve causes pupil dilation but again it will respond to pilocarpine as receptors are intact.

Some important MCQ points related to above information.
1) Echothiophate is also M3 agonists. It is an anti-glaucomic drug which acts by promoting drainage of fluid via schlemm's canal.
Adverse effect: Causes cataract.

2) Adrenergic drugs causes mydriasis (Stimulation of Alpha-1 receptors) and Anticholinergic drugs (Inhibiting M3 receptors) causes mydriasis and cycloplegia.

Tips to get interviews in top-tier residency programs

Who didn’t dream about starting his residency in a great famous program? What is your dream program? Is it Harvard? Yale? John Hopkins? Stanford?......and the list goes on..

It is hard but it is not impossible. Besides having nice USMLE scores, here are some points that make your application stands out:

1- Research
Doing a research in big institutes may help in getting a call from these places. While doing your research, you will be able to meet new people, some of them may know a person who is related to the residency selection process. At the same time, you are showing your commitment, social skills and your willingness to be a part of the team.
Another point to consider is having publications in international journals with a high impact factor. This includes but is not limited to JAMA, The Lancet, Nature, Cell. Whether you worked in institutes in the US to have these publications or you were involved in an international research that was eventually published in these journals, having such accomplishments is a great addition to your application.

2- MPH and/or PhD
Having a Masters degree - especially if done in the US - can be a big plus for some university programs. You may do masters in biostatistics,epidemiology and many others. It may be costly and lengthy (a year or two) but it's worth it.

3- Preliminary (transitional) year
Doing a preliminary year in some high-tier residency programs may be your winning ticket to enter that program. You may match in the same program or apply to and get interviewed by another amazing program since you will now have a 1 year of fully accredited USCE (United States Clinical Experience) in addition to the experience and knowledge that you gain.

4- Contacts
It is amazing how social life shapes us as humans. The importance of having contacts or making new ones during your research, MPH or preliminary year can’t be overemphasized. Programs prefer a person who they already know and whom they are sure they can work with.
Consider attending conferences in your field too, Pediatrics, Internal Medicine...etc.

5- Exceptional Academic Record
Famous institutes like applicants who are bright, smart and committed. An “excellent “academic record helps to prove this.

6- LUCK
Believe it or not, occasionally, luck plays a role here. Be outgoing and interact nicely with as many people as you can. Being in the right time at the right place is what you need sometimes!

Finally, for all AMGs and IMGs, always remember that the journey of a thousand miles begins with a single step. Start now and chase your dreams :)

-Murad

Complications of massive blood transfusion

Hii everyone! 

Massive blood transfusion is defined as

Complications from massive transfusion include :
1) Hypothermia
2) Hypocalcemia - because citrate present in transfused blood is a calcium chelator, it decreases the available calcium.
3) Acidosis - as citrate is acidic in nature.
4) Hyperkalemia - as Hydrogen ions are present in excess due to acidosis, it is compensated by H+ loss in urine and K+ is regained back into blood. So this causes hyperkalemia.
5) Hypokalemia - in stored blood, the Na+-K+ pump is less functioning,  so there is decrease in intracellular K+ in stored blood.  But after blood transfusion, the Na+ K+  pump again starts functioning and increases intracellular K+, this leads to decrease in the available K+ outside the cell causing hypokalemia.
6) Dilutional coagulopathy - massive blood transfusion leads to dilution of clotting factors . It later manifests as DIC-like leading to multiorgan failure and death.

Thanks for reading.

Madhuri.

Complications of blood transfusion

Hii everyone!
This post is about the complications from a single blood transfusion.

1) The most common complication is febrile nonhemolytic tranfusion reaction(FNHTR). -- this occurs due to anti-HLA antibodies in the recipient which kills WBCs leading to release of interleukins and cytokines which are pyrogens. So the treatment is antipyretics.
2) Urticaria - it is due to IgE antibodies in plasma. So we give antihistamines to control it.
3) Hemolytic transfusion reaction - due to antibodies against RBCs. This is rare.  It may occasionally occur due to clinical errors in pretranfusion tests.
4) Infections - bacterial infection due to faulty storage, hepatitis, HIV, malaria.
5) Air embolism
6) Thrombophlebitis
7) Transfusion- related acute lung injury - usually occurs within 6 hrs after transfusion.

Hope this helps.

Madhuri

MCQ mnemonics series: Genital tuberculosis most common site

#Obs_Gyn
Question:
Most common site of genital tuberculosis is?
(A) Fallopian tubes
(B) Uterus
(C) Ovary
(D) Fimbriae
________
Answer:

MCQ mnemonics series: Fusion inhibitors

#Pharmacology
# Antiretroviral drugs
Question
-
*Fusion inhibitor approved for use in HIV is*
a. Enfuvirtide
b. Atazanavir
c. Cobicistat
d. Rilpivirine
-
Answer:

MCQ mnemonics series: Naturally occurring anticancer drugs

#Pharmacology
#Anticancer Drug

Question
-

*All of the following are naturally occurring anticancer drugs except*

a. Irinotecan 

b. Paclitaxel
c. Etoposide
d. Chlorambucil
-
Answer