Friday, March 22, 2019

Mnemonic: Incubation Period of Hepatitis

Hey guys, here’s a simple little mnemonic to remember the incubation period of various hepatitis infections.

Rule of 4 to 8:

Hep A - 4 weeks
Hep E - 5 to 6 weeks
Hep C - 7 weeks
Hep B/D - 8 to 12 weeks

Pay attention to the order of Hep infections from 4 to 8.

Why A&E first? That’s because they enter through the mouth (feco-oral mode of transmission) and your mouth is the first part of your GI.
Remember Hep D co-infects or super-infects Hep B.

- Ashish Singh

Thursday, March 21, 2019

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.

About me by Srikar Sama

Hello there awesomites!

I am a new author here. I am really excited to be here!!! Let me introduce myself


I am Dr. Srikar Sama currently doing internship from Gandhi Medical College, Hyderabad, India. I'm currently preparing for step1 and hope to match into IM/Radiology soon :)

Talking about my hobbies,I love Sci-Fi and fantasy movies (Huge fan of MCU too :P).
I'm obsessed with Game of Thrones, Breaking bad and House MD💙. 
I love dogs, especially Samoyed😍.
I like to travel, meet new people and want to taste local cuisine in all the cities I visit :P
I also love anime(Death Note is my all time fav!!!!), Playing video games and cricket :)

Thanks IkaN for giving me this opportunity! I love making new mnemonics and writing articles for this blog!! I hope you'll enjoy reading my articles.
That'll be all for now. Good luck awesomites.Love Y'all. Live long and prosper✌

-Srikar Sama.

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.

Wednesday, March 20, 2019

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.

Tuesday, March 19, 2019

Step 2 CS: Neurology Case mnemonic

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

Right to left shunt causing Hypoxemia

A right-to-left shunt exists when blood passes from the right to the left side of the heart without being oxygenated. There are two types of right-to-left shunts:

●Anatomic shunts exist when the alveoli are bypassed. Examples include intracardiac shunts, pulmonary arteriovenous malformations (AVMs), and hepatopulmonary syndrome.

●Physiologic shunts exist when non-ventilated alveoli are perfused. Examples include atelectasis and diseases with alveolar filling (eg, pneumonia, acute respiratory distress syndrome).

Right-to-left shunts cause extreme V/Q mismatch, with a V/Q ratio of zero in some lung regions. The net effect is hypoxemia, which is difficult to correct with supplemental oxygen.

The degree of shunt can be quantified from the shunt equation:

Qs/Qt  =  (CcO2  -  CaO2)  ÷  (CcO2  -  CvO2)

where Qs/Qt is the shunt fraction, CcO2 is the end-capillary oxygen content, CaO2 is the arterial oxygen content, and CvO2 is the mixed venous oxygen content. CaO2 and CvO2 are calculated from arterial and mixed venous blood gas measurements, respectively. CcO2 is estimated from the PAO2.

Source: UpToDate

Bhopalwala. H

Causes of Hypoventilation

Hypoventilation — 

The lung alveolus is a space in which gas makes up 100 percent of the contents. This means that once the partial pressure of one gas rises, the other must decrease. Both arterial (PaCO2) and alveolar (PACO2) carbon dioxide tension increase during hypoventilation, which causes the alveolar oxygen tension (PAO2) to decrease. As a result, diffusion of oxygen from the alveolus to the pulmonary capillary declines with a net effect of hypoxemia and hypercapnia. Because the respiratory quotient (Defined as CO2 eliminated/O2 consumed) is assumed to be 0.8, hypoventilation affects PaCO2more than O2.

Hypoxemia due to pure hypoventilation (ie, in the absence of an elevated A-a gradient) can be identified by two characteristics. First, it readily corrects with a small increase in the fraction of inspired oxygen (FiO2). Second, the paCO2 is elevated. An exception exists when the hypoventilation is prolonged because atelectasis can occur, which will increase the A-a gradient . Abnormalities that cause pure hypoventilation include:

●CNS depression, such as drug overdose, structural CNS lesions, or ischemic CNS lesions that impact the respiratory center

●Obesity hypoventilation (Pickwickian) syndrome

●Impaired neural conduction, such as amyotrophic lateral sclerosis, Guillain-Barré syndrome, high cervical spine injury, phrenic nerve paralysis, or aminoglycoside blockade

●Muscular weakness, such as myasthenia gravis, idiopathic diaphragmatic paralysis, polymyositis, muscular dystrophy, or severe hypothyroidism

●Poor chest wall elasticity, such as a flail chest or kyphoscoliosis

Bhopalwala. H

Thursday, March 14, 2019

Types of Sphenoid Sinues.

Hello Guy's!

Here's a sneak peek into the world of Neurosurgery!

In cases of Pituitary Adenomas, the general surgical approach is a TransNasal TransSphenoidal Approach for the excision of the lesion.

To know the type of sphenoid sinus is an important step in the pre-operative planning for the surgery. It also helps in estimating the site where we are most likely to encounter the tumor and the pituitary gland.

Hamburger classified 3 types of pneumatization based on its relationship to the sella turcica.

1)Conchal (rudimentary or absent sphenoid sinus)

2)Presellar (a posterior sphenoid sinus wall that is separated from sella by thick bone).

3)Sellar (a posterior sphenoid sinus wall that is adjacent to sella).

That's all for now... Time to Scrub.

Let's learn Together!

~Medha Vyas.



Tuesday, March 12, 2019

Restrictive vs Liberal approach to transfusion in Sepsis

Hello everyone, 

Here are some studies on approach to blood transfusion during sepsis:

One multicenter randomized study of 998 patients with septic shock reported no difference in 28-day mortality between patients who were transfused when the hemoglobin was ≤7 g/dL (restrictive strategy) and patients who were transfused when the hemoglobin was ≤9 g/dL (liberal strategy) . The restrictive strategy resulted in 50 percent fewer red blood cell transfusions (1545 versus 3088 transfusions) and did not have any adverse effect on the rate of ischemic events (7 versus 8 percent).

One randomized trial initially reported a mortality benefit from a protocol that included transfusing patients to a goal hematocrit >30 (hemoglobin level 10 g/dL) . However, similarly designed studies published since then reported no benefit to this strategy. 

Bhopalwala. H

Source: UpToDate 

Norepinephrine in ICU

Norepinephrine (noradrenaline) Levophed

8 to 12 mcg/minute (0.1 to 0.15 mcg/kg/minute)

A lower initial dose of 5 mcg/minute may be used, eg, in older adults 2 to 4 mcg/minute (0.025 to 0.05 mcg/kg/minute) 35 to 100 mcg/minute (0.5 to 0.75 mcg/kg/minute; up to 3.3 mcg/kg/minute has been needed rarely)

Initial vasopressor of choice in septic, cardiogenic, and hypovolemic shock.
Wide range of doses utilized clinically.

Must be diluted; eg, a usual concentration is 4 mg in 250 mL of D5W or NS (16 micrograms/mL).

Bhopalwala. H

Milrinone in ICU

Inotrope (nonadrenergic, PDE3 inhibitor)

Milrinone Primacor

Optional loading dose: 50 mcg/kg over 10 minutes (usually not given) 0.125 to 0.75 mcg/kg/minute

Alternative for short-term cardiac output augmentation to maintain organ perfusion in cardiogenic shock refractory to other agents.

Increases cardiac contractility and modestly increases heart rate at high doses; may cause peripheral vasodilation, hypotension, and/or ventricular arrhythmia.

Renally cleared; dose adjustment in renal impairment needed.

Must be diluted; eg, a usual concentration is 40 mg in 200 mL D5W (200 micrograms/mL); use of a commercially available pre-diluted solution is preferred.

Bhopalwala. H