A-a Gradient

A-a gradient =[PAO2 - PaO2]
where:

A-a gradient = difference between alveolar PO2 and arterial PO2

PAO2 = alveolar PO2 (calculated from the alveolar gas equation)

PaO2 = arterial PO2 (measured in arterial blood)

PAO2 =150 - PaCo2/0.8

Normal range for A-a gradient is

10-15 mm Hg

ALL causes of hypoxemia lead to ↑ A-a gradient, EXCEPT:

Hypoventilation, high altitude, upper airway obstruction (e.g. epiglottitis from Haemophilus influenzae, or croup from parainfluenza virus)

Everything else will cause ↑ A-a gradient (e.g. shunt, V/Q mismatch, etc.).  

It's much better to remember the exceptions, then everything else becomes the rule!

Also to adjust for age, the thumb rule to calculate A-a gradient is :

Age /4   plus 4

A-a gradient >30 is considered elevated regardless of age.

Bhopalwala. H

Catheter Removal Timing

Removal — Following diagnosis of catheter-related infection, catheter removal is warranted in the following circumstances :

●Severe sepsis

●Hemodynamic instability

●Endocarditis or evidence of metastatic infection

●Erythema or exudate due to suppurative thrombophlebitis

●Persistent bacteremia after 72 hours of antimicrobial therapy to which the organism is susceptible

Source :Uptodate

Bhopalwala. H

Lung Biopsy in VAP

Lung biopsy in Ventilator-associated Pneumonia may be reserved for patients in whom infiltrates are progressive despite antibiotic therapy or patients in whom a non-infectious etiology is suspected.

The purpose of acquiring tissue under these circumstances is to identify a pathogen that may have been missed with previous sampling or a pathogen that is difficult to culture (eg, fungus, herpes viruses) or to identify a noninfectious process masquerading as infection (eg, cancer, cryptogenic organizing pneumonitis, lymphangitis, interstitial pneumonitis, vasculitis).

Source: Uptodate

Bhopalwala. H

Just when you lose hope....

(This is a bit of an off-academic post. So if you are on exam season, avoid reading this.)

Being a doctor!..... we all have dreamt of it. Since we were kids we wanted to wear that stethoscope, walk in long hall ways, go to those people with pain and help them...

You wil watch a TV series and when a surgeon would say "Scalpel please!" you feel goosebumps thinking one day you wanna do it...

But there are somedays you just get home or to hostel from medschool or hospital, and you just don't want to do it anymore. You feel like your passion is lost. You feel like you are no more yourself!

YES! We all have gone through this at least once or even more times in our lives. And when you say this, many other medical students will relate to you too.

Whenever you feel so demotivated, just think WHY YOU STARTED THIS AT THE FIRST PLACE? Did you do it by your will? What made you decide this?

For an example, I always wanted to be a doctor, but my will to become a doctor became so strong when my grandpa passed away in a govt hospital because the doctor in charge didn't diagnose that he was having a heart attack. That day I decided I want to be that doctor who will correctly diagnose and treat people to the best capability I can. I wanted to stop anyone else's family member to pass away because of gross incapacity of a doctor.

You may also have a reason like this if you dig inside your mind. And you will find this reason to fire you up again. To make you push through that one more chapter. Go to that one more ward with a wide smile despite you are sleepless and tired.

Find your reason to stay, not to leave! Because once you are on this voyage, you have decided to work for the betterment of the world and the people, and if you quit midway, it's such a waste, my friend!

Many people dream to be in our shoes. If we give it up, we just are ruining a chance of someone else to be a doctor. So make that medschool seat you owned, be worth it.

Another thing! Going through medschool is not a single man's job. It needs hell load of a support. Find this support system in your family, in your significant other, in your friends, and anyone who would give you strength to carry on, and someone who would motivate you, someone who would be there to say "You can do this! I'm with you!".

Medical books are boring, but books are not the only way you can learn anymore in this digital world. You have millions of videos and interactive websites you can find. You have blogs like our www.medicowesome.com where we breakdown big medical info into small pieces and clarify.

Get your stuff together, clean up your workspace. Cleaner table will motivate you to study too. Use some motivating words in front of your workspace, On your phone's wall paper, On your notebooks! Simply everywhere you would see. If someone would judge you for that, make them your motivation too. Stick up a motivating note on their forehead too! 😂 Just kidding! Ya just keep that smile on always!

Life is great! Medical life is even greater! With all its failures, late night cries, exam phobhias, senior bullies, colleague dramas, its all worth it.

Finish your degree...! This pain lasts only few years! Once you are a fully fledged doctor, you can go ahead and be that wonderful human being you always wanted to be! Don't kill that wonderful person even before you get there!!

We are all voyagers of this same hard journey wherever we are in this world! So let's do this! And in any case you need someone to guide you through your academic related depression or demotivation, always count on us here in Medicowesome!

Have a great day and go own that damn degree!!! 😍

Good luck! See ya later!

Yours,

Jay.

Diagnosing the cause of polycythemia

Polycythemia refers to an increased hemoglobin concentration and/or hematocrit in peripheral blood.
For Diagnosing the specific cause of polycythemia follow these 3 steps:

STEP1: First check for RBC mass
1)Elevation of Hgb and/or Hct due to a decrease in plasma volume alone (ie, without an increase of the RBC mass) is referred to as relative polycythemia.

2)An increase of RBC mass refers to Absolute polycythemia. It can be categorized as either primary or secondary polycythemia.

STEP2: To diagnose the causes of absolute polycythemia. Check for EPO levels
1)Primary polycythemia is caused by a mutation in RBC progenitor cells that results in increased RBC mass. So there is a decrease in EPO levels. Ex: polycythemia vera (PV)
2)Secondary polycythemia refers to an increase of RBC mass caused by elevated serum EPO. Most often, this is due to an appropriate physiologic response to tissue hypoxia, or by autonomous EPO production(eg, an EPO-secreting tumor) 

STEP3: To diagnose the causes of secondary polycythemia. Check PaO2 and SaO2 levels
1)If PaO2<65% and SaO2<92% then it is because of chronic hypoxia due to high altitude, COPD, Smoking, etc.
2)If PaO2 and SaO2 levels are normal then consider EPO-secreting tumor(renal cell carcinoma, pheochromocytoma).

-Srikar Sama

Places to Target for Research

Places to target first for a Research Position (Big Guns) :

Mayo Clinic, Rochester

Mayo Clinic, Florida

Cleveland clinic, Ohio

Cleveland clinic, Florida

Email Format for Research

Email Format  for a Research Position

Hello Dr. XYZ,

I am ABC, a medical student, currently doing clinical elective rotations.

I'm highly interested in cardiology. Your /Case Western Reserve University's research work ( refer to either the person's or the University's work) , particularly in general cardiology and electrophysiology is exemplary.

I believe you accept volunteer Research Scholars. It would be an honor to work in this institute as a Research Scholar.

I would be willing to work for a year, and would also consider an unpaid position.

I am attaching my CV with this email.

Hoping to hear back from you.

Wish you a happy new year.

Thanks.

Hope this helps :)

Bhopalwala. H

How to Land a Research Spot in USA

Hey guys, how's it going?

So this post is going to be about how to land a research position in USA.

First of all I would like to briefly speak about  why it is important to have some research experience in USA. Common idea is it helps people to build a strong CV to cover up low scores or any red flags in the CV. What I have realized is that it is not the only benefit, to get into a competitive specialty for residency and also for future fellowships it's very important to have some research background in the field of your interest.

Now let's talk about the steps to go through before you land a research spot.

Catheter Related Candidemia Treatment Indications

Empiric therapy for suspected catheter-related candidemia should be administered for septic patients with the following risk factors:

●Total parenteral nutrition

●Prolonged use of broad-spectrum antibiotics

●Hematologic malignancy

●Hematopoietic cell or solid organ transplant

●Femoral catheterization

●Colonization due to Candida species at multiple sites

Source: Uptodate

Bhopalwala. H

Antibiotic Lock Therapy

Antibiotic lock therapy —

The premise of ALT is to achieve sufficient therapeutic concentrations to kill microbes growing in a biofilm . ALT may be a useful adjunctive therapy together with systemic antibiotic therapy for intraluminal infections due to coagulase-negative staphylococci or gram-negative organisms in the setting of CRBSI (Catheter Related Blood Stream Infection) when the catheter cannot be removed .

ALT should not be used for extraluminal infections nor for management of infections due to S. aureus, P. aeruginosa, drug-resistant gram-negative bacilli, or Candida.

Source: Uptodate

Bhopalwala. H

Timing of Catheter Replacement in CRBSI

In general, the patient should receive antibiotic therapy for at least two to three days following device removal prior to device replacement. At the time of device replacement, the patient should be hemodynamically stable with negative blood cultures and no sequelae of bloodstream infection .In addition, for patients with CRBSI ( Catheter Related Blood Stream Infection) due to S. aureus, a new catheter may be placed if additional blood cultures demonstrate no growth at 72 hours

Source: Uptodate

Bhopalwala. H

Immunization certificate sample for electives and observerships

Hello,

Since many of you emailed me regarding the  immunization form, I thought of sharing it on Google Docs.

Step 2 CS: Neurology Case mnemonic

The following mnemonic (HDFC ST) helps me cover all bases in a Neurology case.