Defining Systemic Inflammatory Response Syndrome (SIRS) and Sepsis Criteria

Friday, February 17, 2012  at 7:59 PM
The body’s response to inflammation and infection has been characterized by the American College of Chest Physicians and Society of Critical Care Medicine. These organizations defined a four step pathway to determine when a body is responding to inflammation and when that inflammation is caused by an infectious organism. This pathway consists of the Systemic Inflammatory Response System (SIRS), Sepsis, Severe Sepsis, and Septic Shock. This post will explain what these terms mean and how to diagnose them.
  
Systemic inflammatory response syndrome (SIRS) is the term used to describe the physiologic response to inflammation. This inflammation can occur from any source, and does not have to be from an infection. The criteria are listed below and at least two must be present to diagnose SIRS.

Systemic Inflammatory Response Syndrome (SIRS) Criteria:
- Temperature >38⁰C (100.4⁰F) or <36⁰C (96.8⁰F)
- Heart Rate >90
- Respiratory Rate >20 or PaCO2 <32
- White Blood Cell (WBC) Count >12,000 or <4,000 or >10% bands
*PaCO2 is measured by an arterial blood gas. Bands refer to immature neutrophils.

Sepsis is diagnosed when a patient meets SIRS criteria, and has a documented or suspected source of infection. Infection means inflammation caused by microorganisms. These microorganisms include bacteria, fungi, viruses, and parasites. Accepted ways to document the presence of an infection are by blood culture, urine culture, sputum culture, imaging showing pneumonia or a perforated viscous, and by the existence of WBCs in normally sterile fluid.

Severe sepsis is diagnosed when a patient meets sepsis criteria, and has signs of end organ damage or hypoperfusion (decreased blood flow). Signs of end organ damage include PaO2/FiO2 <300 indicating acute lung injury (<200 indicates ARDS), lack of bowel sounds indicating ileus, decreased urine output (oliguria), increased total bilirubin, and low platelets (thrombocytopenia). Signs of hypoperfusion include an increased lactic acid, low blood pressure, decreased capillary refill, and change in mental status.

Septic shock is diagnosed when a patient meets severe sepsis criteria, and has sepsis-induced hypotension that is refractory to fluid resuscitation. Hypotension is defined as a systolic blood pressure < 90, a mean arterial pressure < 60, or a decrease in systolic blood pressure > 40. A patient is considered to have not responded to fluid resuscitation after 20ml/kg of crystalloid solution has been administered.

The figure below summarizes the sepsis pathway and highlights the fact that it is a progressive diagnosis, with each new step including the criteria of the one behind it. SIRS and sepsis is an important diagnosis to keep in mind with each new patient. If these criteria are applied the diagnosis will be harder to miss.


Sources:
Bone, R., R. Balk, F. Cerra, R. Dellinger, A. Fein, W. Knaus, R. Schein, and W. Sibbald. "Definitions for Sepsis and Organ Failure and Guidelines for the Use of Innovative Therapies in Sepsis. The ACCP/SCCM Consensus Conference Committee. American College of Chest Physicians/Society of Critical Care Medicine." Chest 101.6 (1992): 1644-655. Web. 17 Feb. 2012. <http://chestjournal.chestpubs.org/content/101/6/1644.full.pdf+html>.
Dellinger, R. Phillip, Mitchell M. Levy, Jean M. Carlet, et al. "Surviving Sepsis Campaign: International Guidelines for Management of Severe Sepsis and Septic Shock: 2008." Critical Care Medicine 36.1 (2008): 296-327. Web. 17 Feb. 2012. <http://www.survivingsepsis.org/About_the_Campaign/Documents/Final%2008%20SSC%20Guidelines.pdf>.
Levy, Mitchell M., Mitchell P. Fink, John C. Marshall, Edward Abraham, Derek Angus, Deborah Cook, Jonathan Cohen, Steven M. Opal, Jean-Louis Vincent, and Graham Ramsay. "2001 SCCM/ESICM/ACCP/ATS/SIS International Sepsis Definitions Conference." Critical Care Medicine 31.4 (2003): 1250-256. Web. 17 Feb. 2012. <http://www.springerlink.com/content/7wbtu6v6ly8nvhmk/>.
Loma Linda University. "The STOP Sepsis Bundle Toolkit." CrashingPatient.com. Loma Linda University Medical Center, Sept. 2005. Web. 17 Feb. 2012. <http://crashingpatient.com/wp-content/pdf/Loma%20Linda%20STOP%20Sepsis%20Bundle.pdf>.

Top 10 Clinical Criteria/Scoring Systems for Internists and Medical Students

Thursday, February 16, 2012  at 11:39 PM
Clinical scoring systems, clinical criteria, and clinical prediction rules are used widely in medicine and academics. They are used to aid physicians in their clinical decision making and finalizing a diagnosis. Although they should never be used in place of a physician’s sound clinical judgment, they are great clinical tools and methodologies used to organize data.

Below I have listed my “Top 10 Clinical Criteria/Scoring Systems for Internists and Medical Students.” As a medical student whether you want to be an internal medicine doctor or not, you will be using these on your medicine and hospital rotations. These are also important for Interns and Internal Medicine physicians to know.

1. Systemic Inflammatory Response Syndrome (SIRS) Criteria. The first set of criteria along the sequence leading to septic shock in critically ill patients. The sequence is SIRS → Sepsis → Severe Sepsis → Septic Shock.

2. Acute Respiratory Distress Syndrome (ARDS) Criteria. Used to diagnose ARDS which affects the lungs in critically ill patients.

3. Wells’ Criteria. Two separate sets of criteria. One is for determining the risk of pulmonary embolism (PE) and the other is for determining the risk of deep vein thrombosis (DVT).

4. Ranson’s Criteria. Used for determining the prognosis and severity in patients with pancreatitis.

5. CHADS2 Score. Used for determining the risk of stroke in patients with atrial fibrillation.

6. TIMI Score. Two separate sets of criteria. One is for risk of death in patients with unstable angina or Non-ST Segment Elevation Myocardial Infarction (NSTEMI). The other is for risk of death in patients with ST segment elevation myocardial infarction (STEMI).

7. Light’s Criteria. Used to distinguish transudative from exudative pleural effusions.

8. APACHE II Score. Used to determine the risk of death in ICU patients.

9. Child-Pugh (Child-Turcotte-Pugh) Score and Model for End-Stage Liver Disease (MELD) Score. Two separate sets of criteria. Both are used to determine the prognosis and the need for transplantation in patients with chronic liver disease.

10. CURB-65 Score and Pneumonia Severity Index (PSI)/PORT Score. Two separate sets of criteria. Both are used to determine the risk of death in patients with community-acquired pneumonia (CAP).

Other important clinical scoring systems/criteria to know (but did not make the top 10):

- Modified (Revised) Jones Criteria for diagnosing rheumatic fever.
- Modified (Revised) Duke Criteria for diagnosing infective endocarditis.
- Clinical Institute Withdrawal Assessment for Alcohol (CIWA-Ar) Score for determining the need for treatment in alcohol withdrawal patients.
- Rockall Score for determining risk of death and re-bleed in patients with an upper gastrointestinal (GI) bleed.
- Modified Centor Score for determining the probability of Strep throat (caused by Group A β-hemolytic Streptococcus pyogenes) in patients with pharyngitis (sore throat).
- National Emergency X-Radiography Utilization Study (NEXUS) Criteria for determining the need for imaging of the cervical spine (C-spine) in patients with injuries.

The list above is by no means exhaustive or complete, but consists of the most common and clinically relevant criteria/scoring systems that I have encountered in my clinical experience. If I have made an error by omission, or you feel that one should not be included, please comment below.

Top 10 Things Medical Students Should Have in Their White Coats

Friday, February 10, 2012  at 4:49 PM
Top 10 Things Medical Students Should Have in Their White CoatsMedical students’ white coats are short, but still have a lot of pockets to carry necessary supplies. These white coats are notorious for becoming heavy, so I have come up with the “Top 10 Things Medical Students Should Have in Their White Coats,” to help lighten the load.

1. Pens. Write notes, take notes, and keep extras.

2. Smart Phone. For apps like Epocrates and Lexicomp, internet access and keeping in contact with your team.

3. Stethoscope. Listen to the heart, lungs and abdomen. I use the Littmann Cardiology III. The Littmann Master Cardiology is great as well.

4. Notepad. Remember what you have learned and write things to look up later.

5. Penlight. Check pupils, mouth and light up dark spaces. Streamlight makes a great one.

6. Pocket Medical Book. Washington Manual, Pocket Medicine, Boards and Wards or Medicine Recall. The main thing weighing your coat down, but the one you will be using the most. Pick your favorite one and keep it close by.

7. Pocket Pharmacopeia. Tarascon Pocket Pharmacopoeia, I prefer the bigger Lab Coat Edition.

8. Reflex Hammer. Examine that Peripheral Nervous System.

9. Maxwell. Inexpensive quick medical reference for ACLS, note formats, lab values and formulas.

10. Snack. Only you can prevent hypoglycemia.

Many other things may end up in your white coat pockets, but these top 10 things will keep you on the road to success.

Comment below and share what necessities you keep in your white coat and what your favorite pocket guides are!

How to Excel on an Internal Medicine Sub-Internship Rotation

Thursday, February 9, 2012  at 8:31 PM
Once you have decided that you want to match into an internal medicine residency, you should try to schedule as many sub-internship or “audition” rotations as possible. Definitely schedule these at your top program choices, and then try to do more at other programs that you are interested in knowing more about. The optimal time to schedule these will vary with program availability and your schedule, but there are a couple of important points to keep in mind.

Initially, make sure to contact the program to find out when their interview season is, and then make sure to schedule your audition rotation during that period. This is important because the majority of the time you can also interview at the program while you are there for your sub-internship rotation. It is also a good idea to try to schedule your interview near the end, or at least half-way through, your rotation so that the residents, attendings and program director have a chance to get to know you. The programs are usually very happy to work with you to schedule your interview while you are already there, especially if you have traveled from out of town. How to excel on an Internal Medicine residency interview will be covered in a future post. I will update this post when that article has been posted.

Below I have described my tips on how to perform well during your internal medicine sub-internship (audition) rotation, so that you can impress your team and increase your chances of getting an interview and then a residency position at the program of your choice. Since I have had personal experience in doing several audition rotations in different parts of the country, and I will (hopefully) match into an internal medicine residency very soon, I hope that these strategies will be useful to you. These points are arranged in order of preference, but they are not that difficult so you should be able to perform all of them!

Update (2/13/11): I have successfully matched into my #1 choice for Internal Medicine residency, proof that these strategies do work!

1. Make the Intern’s Life Easier. Your primary job while on this rotation is to do everything you can to make life easier for the intern. Pretty much all of the other rules follow after this one. The things you will be doing to fulfill this rule will vary individually from intern to intern, and more specific things you can do are discussed below. However, be sure to ask the interns and residents on a daily basis if there is anything you can do to help, without being a pest. Always be actively looking for jobs that you can do, whether that is gathering charts, keeping a to-do list, or re-examining patients. Keep this rule in mind during your time on the floor and you will do very well.

2. Prove You Can Do the Intern’s Job as Well or Better than Him/Her. This is another rule that encompasses all the others, but is important to keep in mind at all times. There are really not any other specific things you can do to fulfill this rule other than what is listed below. Always be sure to work your hardest, don’t complain, and give 100% every day. Show that you are interested and have enthusiasm about what you are doing, because this is what you want to do for the rest of your life, right?

3. See All Patients and Write All Notes Before Rounds. Nothing shows more that you are not ready for rounds when you are furiously scribbling on your progress notes as the team is about to begin. Arrive to the hospital early enough so that you have plenty of time to see all of your assigned patients and complete all of your notes before rounding. It is also helpful to print out any imaging study reports, EKGs, culture results, etc. to give to the attending to review. Be on time to rounds with your notes ready, having reviewed the chart, and with a good assessment and plan in mind. This brings us to our next point.

4. Write Excellent Progress (SOAP) Notes. Hopefully you will already be familiar with how to do this from your third year medicine rotations. Remember the basics of the SOAP note format, and don’t put things in the wrong section. The overview of how to write a SOAP note is the topic of another post, but there are some extra ways to make your note great. Write down a list of the patient’s medications in the margin. For antibiotics, make sure to include the start date and/or the current day of treatment. Make sure your handwriting is legible. Don’t use pencil or marker as it may smear, and don’t use different colored ink on your notes. Sometimes nurses, case managers, and other staff write in the chart with alternate colored ink, so get in the habit of only using black pen. For abnormal labs, also put the previous day’s value off to the side so you can keep track of trends. Talk to the patient’s overnight nurse to see if any acute events happened during the previous night. The interns, residents and attendings all look at your note even if it does not become a permanent part of the patient’s chart, so don’t skimp on the details. Include a differential diagnosis in your plan for your assessment. Write out your thought process including what labs you want to order, what medications to start/stop/continue, consults you want to ask for, and imaging you want to obtain. Don’t worry about being 100% accurate. The main thing you want to focus on is your thought process for your plan and providing evidence and justification for it. Writing an exceptional progress note will give you a step-up for the next point.

5. Actively Participate in Rounds and Morning Report. Active participation means that you are presenting your own patients during rounds to your attending physician. Hopefully you have had a lot of practice with this before your audition rotations, and it will be no sweat. It can be nerve-racking the first time you present to a new attending, but if you have an excellent progress note you can get through it. In addition, make sure to answer pimp questions during rounds and morning report. Just sitting in the background will not help you stand out and be rememberable. Don’t be afraid to speak up and show that you are smart, just be careful not to come across as too confident or that you think you are the smartest person in the room.

6. Post-Round with the Intern. Post-rounding is when you go back through all the patient’s charts and take care of the loose ends. This mostly includes writing orders, discharging patients and dictating. Make sure that you are present for this every day and are available to help in any way that you can. During rounds you should have also been taking notes on what needs to be done for your patients, and you can also help make sure that all of this gets done. The interns will be grateful if you remind them of something they may have missed. You can also help by writing prescriptions and, if students are allowed, even dictating.

7. Be Professional. This should go without saying, but your behavior and appearance should always be a priority. Always follow the dress code. Don’t wear scrubs when everyone else is wearing a shirt and tie. Treat everyone with respect that you come into contact with. Remember that you are in the hospital to learn and that they are allowing you to be there. Do not ever ask if you can go home, and only leave when you are told you can. Never decline when you are asked to do something and always be willing to do little tasks.

8. Present a Lecture, Morning Report, or Journal Article. If there is a practice of students presenting a PowerPoint or an article on their rotation, make sure that you are able to do so before you leave. You can always offer to present a 5-10 minute summary of an interesting subject to your medicine team. It might take a little bit of time to prepare a lecture, but it is a good way to get up front, show your face, impress others, and be rememberable. You want to be able to be recognized come interview time.

9. Take Call. If students are able to take overnight call in the hospital, sign up. This will give you an opportunity to get to know more residents, gain a lot of experience, and show how much of a hard worker you are. Plus, the next day you will be post-call and get to go home early.

10. Eat breakfast. This may seem trivial, but I think it is vitally important. How are you supposed to take care of others if you don’t take care of yourself? This does require waking up earlier in the morning, but it will make the rest of the day smoother. If your brain is low on glucose you won’t be thinking as clearly and your mind will be on your stomach come mid-morning. On my medicine rotations, I liked to finish up my notes while eating breakfast before rounds. Eating breakfast will be especially important once you become an intern and your decisions will be directly affecting patient’s lives.

Medical Demotivational Posters

Monday, February 6, 2012  at 9:16 PM
Demotivational posters have become increasingly popular and some are very funny too. There are a couple sites I found with a few medical themed posters, but I got the idea to post some here from one of my classmates.

Below is the first batch of these posters. I used the AutoMotivator website to create these. The idea for the first two were given to me by a classmate, and the rest were made up by me. If you have any ideas for more, email them to me!

*Quote provided by a classmate
 
*Quote provided by a classmate
 




Feel free to comment on what you think and if you would like to see more!

Circulation of Cerebrospinal Fluid (CSF)

Saturday, February 4, 2012  at 5:44 PM
The flow of CSF through the Central Nervous System is important to understand for the many conditions that can affect it including hydrocephalus, infections, masses, or bleeds.

I have created a flow chart to show the anatomy of the circulation of CSF. It is important to remember that the lateral structures are arranged in pairs, while the midline structures are single. 


A mnemonic to remember the locations of the foramina:
Foramen of Luschka is Lateral
Foramen of Magendie is Medial

Along with the anatomy, it is important to know how to perform a lumbar puncture to collect CSF, which lab tests to perform on it, and how to interpret those lab tests. This information will be discussed in a future post.

Source:
Craig, John A., James Perkins, John T. Hansen, and Bruce M. Koeppen. "Neurophysiology." Atlas of Neuroanatomy and Neurophysiology. By Frank H. Netter. Special ed. Teterboro: Icon Custom Communications, 2002. 61-62. Print.
Johnson, KS and DJ Sexton. Cerebrospinal fluid: Physiology and utility of an examination in disease states. In: UpToDate, Basow, DS (Ed), UpToDate, Waltham, MA, 2012.

Epidural and Subdural Hematomas, and Subarachnoid Hemorrhage Mnemonic

Thursday, February 2, 2012  at 11:20 AM
These three types of brain bleeds are the highest yield to be able to recognize on board exams. Additionally, you definitely do not want to miss these on any patient.

In my studies, I always seemed to have trouble keeping the first two straight (epidural and subdural). I came up with this mnemonic to help me, and hopefully it will help you too.

EpIdural looks like an Ellipse and has a lucId interval.  

SuBdural is caused by Bridging vein rupture. The hemorrhage looks long and thin like a bridge. Bridges cross over areas like the hemorrhage crosses over suture lines.

SuBArachnoid is caused by Berry Aneurysm rupture. They cause a “Bad Ass” headache (aka “worst of life”).

Source:
Le, Tao, and Vikas Bhushan. "Neurology." First Aid for the USMLE Step 1. 2010 ed. New York: McGraw-Hill Medical, 2010. 402. Print.

Peripheral Nervous System (PNS) Physical Examination

Wednesday, February 1, 2012  at 12:03 AM
This post is designed so that you will never have to write “Neuro: Grossly intact” on your History & Physicals again! Writing “grossly intact” is pretty much saying that you didn’t examinate the system at all.

This post will address how to do a thorough peripheral nervous system physical examination for the purposes of a routine history and physical. I do not cover the complete neurological exam in this post, but just focus on the PNS including myotome, reflex, and dermatome evaluation. Of course to complete the neuro exam, cranial nerves and cerebellar testing must also be performed.

I have been on a neurosurgery rotation this past month, and have learned how they perform their physical exams. When examining the PNS, it is especially important to evaluate for radiculopathy and document which nerve root distribution the patient feels pain in.

I have created a chart, located below, to help provide a framework for the evaluation of each spinal nerve root (C1-S5). Examining the PNS should be done in three steps. First, evaluate the myotomes (motor), followed by the reflexes, then dermatomes (sensory) that each nerve root innervates. This information is provided in the chart.

*Click on the chart to enlarge it, then right click on it and select "view image," then right click on it to download.
*Alternatively, you may email me if you would like a bigger size.

For each myotome, the physical movement the muscle performs, the name of the muscle, and the peripheral nerve that innervates the muscle is given. Note that only the most clinically relevant muscles are listed as being innervated by the nerve root(s). Each reflex is only listed beside the main nerve root that innervates it, even though the one above or below may also contribute. For each dermatome, the cutaneous area and the peripheral nerve that innervates that area is given. All dermatome maps are slightly different, so care was taken to list only the most clinically relevant areas and the main peripheral nerves responsible for innervation.

The yellow highlighted areas in the table indicate the most important areas to test on a routine physical exam. The superscript numbers listed before the text in these boxes indicate the recommended sequence of exam. I have also listed on the left side of the table the plexus each nerve root contributes to. For the brachial, lumbar, and sacral plexuses I have listed the main components and what will happen if each of these nerves is lesioned.

In conclusion, do not write or dictate “grossly intact” for your neuro exam! Make sure to list out the nerve roots or muscles you tested, along with each reflex and dermatome. That way you are able to precisely determine where any deficit is located and are able to define it to a single nerve root.

Sources:
Bickley, Lynn S., Peter G. Szilagyi, and Barbara Bates. "The Nervous System." Bates' Guide to Physical Examination and History Taking. 10th ed. Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins, 2009. Print.
Goldberg, Stephen. Clinical Neuroanatomy: Made Ridiculously Simple. Miami: MedMaster, 1994. Print.
Gray, Henry, and Warren H. Lewis. Anatomy of the Human Body. 20th ed. Philadelphia: Lea and Febiger, 1918. Print.
Hoppenfeld, Stanley, and Richard Hutton. Orthopaedic Neurology: A Diagnostic Guide to Neurologic Levels. Philadelphia: Lippincott, 1977. Print.
Le, Tao, and Vikas Bhushan. "Musculoskeletal." First Aid for the USMLE Step 1. 2010 ed. New York: McGraw-Hill Medical, 2010. 368-72. Print.
Netter, Frank H., John T. Hansen, and David R. Lambert. Netter's Clinical Anatomy. Carlstadt, NJ: Icon Learning Systems, 2005. Print.
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