Tuesday, October 16, 2012

Childbirth and Modern Medicine

A fascinating article by Atul Gawande about the history of childbirth and the medical establishment and the ethical considerations facing today's obstetricians.

"The Score"
Published in The New Yorker, Oct 9, 2006


Have you ever wondered why human babies are so much more vulnerable at birth when compared to other newborn mammals? We can't walk, see very far, and our nervous system is still somewhat undeveloped. Turns out it's because of the relatively small size of the human pelvis which is what the baby has to pass through to get born. Since our bodies can't wait for babies to get any bigger, all human babies are effectively born premature and develop the skills most mammalian infants have immediately over the next year or so.

Sunday, October 14, 2012

Losing a Child

An illustrated memoir by Tom Hart and his wife, both artists, about the loss of their two-year-old daughter.

Saturday, October 13, 2012

Oxygenation and Ventilation Are Not Opposites

Breathing has two parts: bringing oxygen into the body, and expelling carbon dioxide from the body. Both are incredibly important.

Why is oxygen important?
With oxygen cut off for a few minutes, the body can't effectively make energy (ATP) and will start shutting down.

Why is getting rid of CO2 important?
If CO2 builds up in the body high enough and for long enough, it can actually put you into a coma. A good way to think about it is that there are actually 3 waste-disposal organs in the body.
1. Intestines - stool
2. Kidneys - urine
3. Lungs - CO2

CO2 is a waste byproduct of the mitochondria doing their work and is just as important to get rid of as what is in urine and what is in stool.

What is Ventilation?
You will often hear people talk about breathing in terms of oxygenation and ventilation. Oxygenation is the breathing in of oxygen, but ventilation is not technically the equivalent word for blowing out carbon dioxide. We actually don't have a good word to specifically mean that. It's a small point, but a conceptually important point:

Ventilation = Air Movement (not the act of blowing off CO2)

Ventilation simply means moving air in and out of the lungs. If this does not happen then yes, you will not be able to get rid of CO2 because air is not moving out of the lungs. But you will also not be able to bring O2 into the lungs if there is no air movement/ventilation so you will not be oxygenating either. 

So ventilation is air movement which is necessary for both oxygenation and blowing off CO2 (we really need a noun specifically for blowing off CO2 . . . expulsion?). Put in another way:

Oxygenation           CO2 Expulsion

Ventilation is the heading under which both oxygenation and blowing off CO2 fall. Again, it may be a small point, but explicitly defining these terms and how they relate to each other makes understanding mechanical ventilation much more conceptually easy when you first start learning about it.

Monday, October 1, 2012

Quick Points on Blood Gases Measurements

This topic has caused me some confusion through my training. Here are some important conceptual points.

There are 3 types of commonly used blood gas tests:

Arterial Blood Gas (ABG)
The best test, taken from an artery presumably before the blood has been used for anything. Tells you the pH, oxygen level (O2), carbon dioxide leve (CO2), and amount of base. Harder to get than other two tests because only a few spots to get arterial blood (usually arteries are deeper, veins are nearer the surface of the skin) or you need a central line to get blood from.

Capillary Blood Gas (CBG)
Blood taken from a capillary. Just as good as as an ABG except you can't trust the oxygen reading. Capillaries are where blood is used by the body, that is, where oxygen is removed from the red blood cells. So the oxygen level is not reliable in this test since you don't know how much has already been removed by the body. The rest of the readings (pH, CO2, base) can be used with confidence.

So what do you do if you really want to know what the oxygen level is? The pulse oximeter (oxygen level reader on patients' fingers) can be used as a stand in in the majority of cases.

CBG + Pulse Oximeter Reading = ABG

Venous Blood Gas (VBG)
Blood taken from the vein. Effectively the same use as a CBG. Good for all the readings except oxygen level so the rules apply.

Obstetrics - Is it PROM, PPROM, or What?

A common point of confusion is what exactly PROM and PPROM mean when talking about a baby being born. When the acronyms are used, there is often some minor doubt as to what exactly we are referring to. There are a few basic concepts here that are straightforward but also important to the health of the baby.

Here are the main concepts:

-What is "rupture of membranes?": The mother's body generally determines when it is time to push out the baby. It does this by having the womb/uterus start to clench (this is what we call Labor) to push the baby out the vagina into the world. When the uterus clenches, it breaks the bag of water inside the uterus (my water broke!) that the baby has been floating in for 9 months. The bag itself is made of two layers which are the membranes that have to break for the water to flow out (the baby isn't going to fit out the vagina if the bag of water is still full). So breaking the water bag that the baby is floating inside = Rupture of Membranes (ROM). So ideally mom's body decides it's time to expel the baby, it starts squeezing, the bag of water protecting the baby breaks, and then some time later the baby is pushed out the vagina. However, it does not always work this way.

-Why do we care about membranes rupturing? The main reason we care is that for it's entire growth in the womb, the baby is immersed in this fluid filled sack. This sack is what protects the baby from bacteria which can cause infection. If the sack wasn't there, bacteria and viruses from places like the vagina could enter the womb and infect the baby. The sack is a barrier for this happening (not perfect, but still very important). So when the sack breaks, the baby loses it's defense barrier. Also, around this time the womb is starting to open up the passage to the vagina to get ready to start pushing the baby out. When the passage starts opening, it creates a direct path for bacteria from the vagina to go into the womb and infect the baby. So having the sack intact, is very important to the baby not getting an infection.

-What is Premature Rupture of Membranes?: So normally the bag of fluid only breaks after it has been squeezed a bit by the uterus during contractions. Sometimes though the bag will break on its own without the uterus making it happen. If the baby is old enough, this doesn't mean that the delivery will not go well, but it does beg the question, "why did this happen?" The main thing we worry about is infection. An infection involving the baby or mother can trigger the water breakage. So if the water breaks without the uterus breaking it itself, you gotta be sure there's no infection going on. Because this is a concerning event, the term Premature Rupture of Membranes is used to emphasize that this is an important event.

Literal Definition:

Premature Rupture of Membranes (PROM) = fluid sack breaks before labor (i.e. the sack breaks on its own with no help from the squeezing of uterus)

-What is PPROM?: this stands for Pre-Term, Premature Rupture of Membranes. This is basically the same thing as PROM except when it happens to a baby less than 37 weeks along. The distinction is made because since the fetus is not old enough to truly be ready to come out, there is a greater risk for problems for the baby once it's been born. 

-What is Prolonged Rupture of Membranes?: this term goes back to the sack being a protective barrier for the baby against infection. It doesn't necessarily have anything to do with PROM either. It just means that there was a longer time between the time the sack breaks and when the baby was fully delivered than is hoped for. This is usually considered more than 1 day. So the baby has had a longer time hanging out in the womb without the protection of the sack so has had more time possibly exposed to bacteria which can cause infections. People often confuse this term with Premature Rupture of Membranes because the acronym would be the same. The key is to remember that there is no acronym for Prolonged Rupture of Membranes. PROM never equals prolonged rupture of membranes.

To review the three terms:
  • PROM: Premature Rupture of Membranes (sack breaks before labor/contractions start; be worried about infection)
  • PPROM: Preterm PROM (same as PROM except when baby is younger than 37 weeks; alerts doctors that there is a higher health risk for the baby since it is not fully developed yet)
  • Prolonged Rupture of Membranes: NO ACRONYM! The time from when the baby loses the sack as an infection barrier to the time the baby is born was long (>1 day; greater time exposed to bacteria in the mother so greater risk of having an infection)

Fetal Circulation & Ductal Dependent Lesions


One thing that is usually not made clear when talking about fetal circulation is why it is specifically set up the way it is. We know that the placenta, interfacing with mom’s circulation, is acting as a substitute for the lungs (gas exchange), and the kidneys and intestines (nutrient and waste exchange). The lungs are full of fluid and consequently have high vascular resistance, so they receive very little of the total amount of blood pumped out by the heart, while the placenta has low vascular resistance to encourage more blood to flow through it. Fetal hemoglobin also plays a part, as it has a greater affinity for oxygen, allowing it to load oxygen from the placenta at the same low O2 saturation that in mom’s adult hemoglobin causes the unloading of oxygen.

Theoretically, the placenta could perform molecule exchange much like a dialysis machine does, by simply taking blood from a blood vessel, performing the exchange, and then delivering the blood back to the systemic circulation via the same or a different vessel. The rest of the circulation would not need to be any different from an adult’s. But it is. Because what’s left out of most discussions is that in addition to gas and nutrient exchange, the fetal circulation is responsible for the preferential delivery of oxygenated blood to the most important organs; the brain, heart and liver. Fetal circulation first drops off a significant portion of oxygenated blood straight to the liver, and then shunts the remainder of oxygenated blood directly to the brain and heart, while it shunts deoxygenated blood past these organs. And this requires three modifications:

1. Ductus venosus (connects umbilical vein directly to the IVC)
2. Foramen ovale (an opening between the shared wall of the left and right atria)
3. Ductus arteriosus (connecting the pulmonary artery to the descending aorta)

Fresh, oxygenated, nutrient-rich blood coming from the placenta via the umbilical vein is divided up between the developing liver and the ductus venosus, which connects to the IVC. This blood from the IVC streams across the right atrium, and is shunted straight through the foramen ovale to the left atrium, where it ends being pumped by the left ventricle to the aortic arch, directly perfusing the brain and heart.

At the same time, the deoxygenated blood from the rest of the body sluggishly enters the right atrium, via the SVC and the IVC distal to the ductus venosus. This blood ends up getting pumped by the right ventricle into the pulmonary artery. Most of it bypasses the lungs and the aortic arch via the ductus arteriosus, and then mixes with the highly oxygenated blood from the aortic arch at the descending aorta, to perfuse the rest of the body.

To recap, despite the fact that highly oxygenated blood from the placenta enters the the right atrium via the IVC, the same place where the rest of the systemic circulation ALSO enters via the SVC and IVC, the anatomy actually encourages ‘preferential streaming’ of the highly oxygenated blood through the foramen ovale into the left atrium and consequently to the brain and myocardium. The deoxygenated blood from the systemic circulation bypasses the aortic arch, therefore never reaching the brain. They only come together at the descending aorta after the brain and heart have received the most oxygen-rich blood, perfusing the rest of the body and flowing via the umbilical arteries back to the placenta, where CO2 and waste products are removed, and O2 and nutrients are picked up.


After birth, fluid in the lungs is cleared and placental circulation is clamped off. Pulmonary vascular resistance decreases, and blood starts flowing into the pulmonary artery, causing a decrease in RA pressure. Blood from the lungs returns to the LA via the pulmonary vein, increasing pressure there. As RA pressures decrease and LA pressures increase, the right to left flow across the foramen ovale and ductus arteriosus decreases, and they both close off soon after birth. The right side of the heart pumps blood to the lungs, the left side to the rest of the body, and congenital heart lesions (structural/anatomic defects of the heart and major blood vessels) involve problems with how these two parts of the circulatory system, driven by different sides of the heart, connect. These lesions can be broken down into three functional categories:

1. circulation bypasses the lungs
            (pulmonary stenosis, pulmonary atresia, tricuspid atresia, tetralogy of fallot)
2. circulation bypasses the body
(aortic stenosis, aortic coarct, hypoplastic left heart syndrome)
3. circulation between the lungs and the body is completely disconnected
            (transposition of the great arteries)

Lesions in all three of these categories can cause parts of the body to not receive any oxygenated blood, evident as cyanosis, and some of these lesions are termed ‘ductal dependent’. This means that the effects of the lesion (poor or no mixing of the two parts of the circulatory system) are mitigated while the ductus arteriosus remains open, (maintaining some mixing of the pulmonary and systemic circulation).*

If a neonate develops cyanosis or dyspnea that is not responsive to supplemental oxygen, then the differential includes problems with oxygen delivery (i.e. lung issue) or problems with circulation itself. This is when it becomes important to assess whether the infant has a ductal dependent heart lesion. Aside from getting an echocardiogram to evaluate the lesion, this is done by monitoring preductal and postductal oxygen saturations, i.e. pulse oximetry of a preductal extremity (one that is supplied by the aorta proximal to where the ductus arteriosus inserts, classically the right arm but also the left) and a postductal extremity (one of the lower legs). A difference of >10% O2 saturation between the two extremities indicates that they are likely getting blood from different parts of the circulation, and the ductus arteriosus is still patent. If there is cyanosia AND the test is positive (i.e. there is an actual difference in oxygen saturations between the extremities), there is a high chance that they have a ductal-dependent cardiac lesion. This means that any worsening cyanosis signifies relative hypoxia of those parts of the body that will soon be getting only deoxygenated blood if the ductus arteriosus closes off completely.

Identifying a ductal dependent lesion is important because we can do something about it: we can medically prevent the ductus from closing using a continuous IV infusion of Prostaglandin E, which relaxes the smooth muscle in the walls of the vasculature. Consequently one of the major side effects of PGE is hypotension, and the infant has to be observed closely while on the drip, with resuscitative fluids and inotropes available. Usually they will require intubation and ventilation as the other major side effect is apnea. (NSAIDS inhibit the COX enzymes that make prostaglandins, so they are absolutely contraindicated.)

*Note that just as lesions are ductal dependent, many lesions are only compatible with life due to additional shunts between the right/pulmonary and left/systemic circulation, e.g. atrial and ventricular septal defects.

Thursday, September 20, 2012

How to Learn (Understand and Memorize) Pediatric Developmental Milestones

Developmental Milestones are the skills babies and young children learn as they grow like walking and talking. They are also the bane of many medical students and pediatric residents because there are quite a few different milestones that we are required to memorize and we have to know exactly at what age we should expect each of these to develop. It is a lot of information. When I had to memorize this stuff I memorized it from this chart:

Needless to say none of this stuff ever stuck in my brain much past the day of the test. So after having to re-memorize the milestones I tried to come up with a better, more efficient way to not only commit the information to memory, but also get a deeper understanding of the topic of development in general.

The following is a paper I wrote that gives a broad overview of the concepts at play in assessing childhood development followed by a methodology for learning the milestones in a fast, efficient, and clinically useful way that will hopefully stick in your head better than a series of loosely related facts. I start with a general overview and then get into the details about how to commit this information to memory in a functional way for both standardized tests as well as use in the clinic.


Why learn it?
Development is an integral part of pediatric practice. Knowing and understanding developmental milestones has important diagnostic application, it separates us from adult medicine, and is infinitely pimpable both by attendings and on our licensing exam. In other words, this stuff is important to know.

How does this all fit together/Global Overview?
We will first discuss why this is clinically important, how it is used in practice, why we define development in four discrete categories (gross motor, fine motor/vision, language/hearing, and social), go through an overview of each developmental category, and most importantly, how to memorize this stuff in a way that is clinically/functionally relevant and will serve you when in clinic, when pimped and, eventually, on our licensing exam.

  1. Why is learning/applying developmental milestones important? Why do we use this modality?
We use milestones for two main reasons:

  1. During early childhood (basically until the age of 5), when kids cannot articulate their inner state, developmental milestones are used as clues to what is going on inside and if any pathology is brewing.
  2. By assessing where the child is in each category, we can tell if delays are isolated to one category (speech delay for example) or appears in multiple categories which will change your diagnostic concerns

  1. How do we use developmental milestones in every day clinical practice?
    1. We assess if the child is meeting milestones in each category for his or her particular age. There are ranges of ages when milestones arrive (refer to Denver Scale). A lot of the classic milestones that we memorize are later in the average range, so if a milestone is not seen by this age, this is possibly a problem. We will later go over some big red flags for certain milestones if not seen by a certain age (a child not walking by 15 months is a concern)..
    2. Example of how we evaluate a six month old at a well child check: At six months, a child should be able to sit up (gross motor), pick up things with a raking grasp (vision &fine motor), babble (language), and recognize family members (social). We ask parents if they see this at home, and observe whether the infant is doing these things in clinic.

  1. Why do we use only these particular four categories? It seems kind of limited in scope. Does this really adequately define a child’s development or are there things we are leaving out? And why do we only really memorize these milestones to the age of 5?
    1. We use these four categories because they are the most easily observable behaviors and we have therefore been able to create norms for when we can expect children to do them.
    2. There are absolutely aspects of development not covered in these four categories. How a child plays is very important in how a child develops, but is way too diverse and individual to create any meaningful way to assess/measure it or create norms. So the four categories that we do use, though chosen out of utility, are good enough to diagnose the vast majority of developmental problems that may arise during a child’s first five years of life.
    3. We only memorize up to age 5 because after that, children are better able to communicate to us their thoughts and feelings, and this is about the age that they enter school and any developmental issue will likely become readily apparent when the child is placed with other children who they will have to interact using all four milestone categories. Any deficiencies will be more obvious because things outside the norm will be visible by comparison to other kids. Also, development is no longer as rapid after age 5, and therefore there is less urgency in diagnosing any problems, and more reliance on things to get lagged socially or academically at school.

  1. So how do I learn all this stuff? Should I learn each milestone category individually? Should I learn a milestone across each category for each age? What information is best learned in a conceptual way? What information do I need to just memorize?
    1. The goal is to learn these milestones in a way that we can use them effectively, quickly, and easily when assessing patients (either at well child checks, outpatient urgent care appointments, or when a child is admitted to the hospital), and also be able to answer quickly when we are pimped or when we see it on a boards exam.
    2. I have tried to memorize these milestones many times since Step 1. I never got a good sense of understanding how everything fits. I’ve had to rememorize these things many times (3rd year pediatric exam, Step 2, Step 3, intern year, board exam) which is clearly not efficient and likely not very effective.
    3. So how do we learn this? It is a mix of conceptual understanding and rote memorization. The best way we have been able to figure out is to (1) Generate an overarching understanding of the development categories (2) Learn why each milestone category progresses as it does in children (why do we crawl before we walk?), and (3) use some memory tricks to learn the most clinically important and most tested milestones for each age. This way you create an overall understanding of what is going on (which is actually fascinating in and of itself) but are still able to quickly recall necessary/important milestones for assessing children and getting pimped.

General Understanding of Each Domain/Domain Overview
The Categories: We use four categories for assessing child development- Don’t memorize the rest of this section, it is only for getting a conceptual overview of the categories, so when we start memorizing details we have a framework to understand the progression of kids’ acquisition of skills.

Gross Motor: this category is the use of all muscles in a way that does not involve hand/eye coordination, which ends up being essentially everything except eye/finger movements: head control, rolling over, sitting, walking, running, throwing (overhand, from the shoulder), stairs, riding bikes, etc.

Fine Motor/Vision: this group is called “fine motor” but should be called hand/eye coordination. Initial milestones involve fixating and following objects with their eyes, and eventually manipulating objects with hands and fingers. Both dexterity and vision are necessary to achieve many of these milestones (block stacking) so that is why these abilities are grouped together.

Language/Hearing: like “fine motor,” “language” should include hearing as the two are intertwined. If you can’t hear, your language is going to be delayed or nonexistent. Language is divided into two categories; the distinction is clinically important. How someone speaks and how many words they know are often the most obvious milestones, and are examples of expressive language (remember Broca). But language is also receptive (does a child understand what is being said; think Wernicke) and this may be less obvious initially. Receptive language deficits are rarer but more concerning, assuming hearing is intact, as it then implies a brain/cognitive problem, as opposed to expressive language deficits which are more likely to be secondary to mechanical issues. For example, kids with Cerebral Palsy may be intelligent and fully aware of their surroundings, but often the initial erroneous assumption on the part of the provider is that they have poor cognition.

Social: This is how a child interacts with other people. Does a child respond to other people’s behavior and show recognition that other people are sentient beings? For example, do they attempt to draw another person’s attention to an object, indicating that they understand other people even have attention to redirect? Kids with Autism can have trouble with this kind of understanding.

General Overview of Milestones for Each Category
It is very helpful to understand the general progression of each milestone category so you can conceptually understand the progression of each category and why most children develop in a predictable manner. This is most helpful in gross motor development, which we will use as a base on which to memorize the milestones of all the other categories for a particular age. Also, we choose which months to assess a child based on when they have well-child visits (because we most commonly won’t see these kids except at these times)

Gross motor Development: Children develop their gross motor skills from head to toe because myelination of nerves happens from head to toe during the first year of life. You first lift your head up (neck), then you roll (using arms), then you sit (waist), then you crawl (knees), then you stand, and then you walk. The goal of the first year is to walk.

Fine Motor Overview: since children don’t use their hands until a few months old, early on we focus on whether the child appears to be able to see things (track objects with their eyes for example). Around four months the fingers come in to play. The goal of the first year is to have a controlled “pincer grasp,” which is the infant being able to pick up small things using the tips of their thumb and index finger. So you look for vision until 4 months, then the kid can grasp objects with all fingers, then discovers their thumb, then learns to use the thumb and fingers together in a controlled way.

Language Overview: just as we watch for vision first in fine motor, a child has to be able to hear to learn to speak. Thus evidence that the child can hear is an important part of the early milestones. The goal of the first year is to be able to say one word (with meaning—i.e. the child says the word with intent and it means the same thing every time). After the first year, we start looking for increased vocabulary, better pronunciation, and combining words into phrases and sentences.

Social Overview: this covers how children relate to other people. We start by looking for how they react to people, initially with a smile, laughs, and then whether they can discriminate parents vs strangers. After that we we assess when a child develops the insight that other people are thinking beings (and thus different from other objects). They will show this by pointing to draw attention, peekaboo, and more advanced ways of playing and interacting). A child with autism will not be attracted to people, faces and language as distinct from objects.

How to Commit This Stuff to Memory
1. First memorize the months of the well child checks. This is important for creating a framework for memorizing the milestones and will also help when you start memorizing vaccine schedules. The timing of both milestones and vaccines is based on this well child check schedule. The visits are 2 days, 2 weeks, 2 months, then add 2 months twice (4 months, 6 months) then space it out as we get less anxious and the rate of expected milestone acquisition declines. So 2d, 2w, 2m, 4m, 6m, 9, 12, 15, 18, 24m, 3y, 4y, 5y.
-So initially think “2,” 2 days, 2 weeks, 2 months, 4 months, 6 months
-after month 6, it is by 3 for four visits, so 9, 12, 15, 18
-after this it is by full years, 2, 3, 4, 5

2. Once this is down, we memorize the gross motor milestones for each visit. This will be the only milestone category that we have to rotely associate with months. We will use it as a memory base and hook the other milestones in to it.
A good way to memorize motor is to divide these milestones into two categories: birth to 1 year, and 15 months to 5 years.

Birth to 1 Year: Remember that the goal of the first year is to be able to walk (walk at 12 months). At six months you are halfway there (remember “sit at six”). Just with these two milestones you can pretty much fill in everything else. Remember that everything is from head to toe. So 2 months (the first time we really check milestones) you check for head lifting (neck control). You roll at 4 months (at level of shoulders and chest). Then, again, at six you sit. You crawl at 9 months and pull to stand (crawl, pull to stand at 9 months) which makes sense as being between sitting and walking.
In Review:
2 months: lift head 45 degrees
4 months: roll over (front to back first, then back to front, easier if you can push off with hands)
6 months: sit (halfway to goal, halfway through year, “sit at six”)
9 months: crawl, stand (halfway between sitting and goal)
12 months: walk (the goal)

15 months – 5 years: Memorize these milestones in a story as they are harder to associate with particular months like the first year. Using this progression story may help you.
15 months: walks well
18 months: throws objects
24 months/2 years: up and down stairs (one foot at a time); run
3 years: Tricycle (3 wheels, 3 years), jump in place
4 years: up and down stairs alternating feet (2 feet x up/down = 4), balance on 1 foot for 4 seconds (legs look like a 4 when on 1 foot), hop
5 years: skip (5 looks like an “S”kips)
Story: a child on the 1st floor of her house sits up, crawls, cruises, then 1) WALKS to stairs, 1.5) THROWS object up stairs, 2) CLIMBS up the stairs and RUNS to his trike, 3) RIDES a trike upstairs, JUMPS off, 4) RUNS down the stairs, HOPS off the stairs and 5) SKIPS away
3. Once you’ve memorized the months of well child checks and corresponding gross motor milestones, begin to memorize the archetype babies for each age group. These little stories incorporate all the other milestones into a single image which is much easier than trying to memorize many unrelated facts. There are some ways to conceptually link milestones across categories, but they are not frequent enough to be useful for fast recall and the salient milestones and timing which is what happens on tests and during morning report. 

Here are all the babies with milestones listed:

2 months: lift head 45 degrees (when laying on face), turns to sound, follows objects past midline, social smile
Parent’s Little Baby: looks up to sound, smiles because he sees both his parents, one on either side of midline

4 months: lift head 90 degrees/raise up to chest, roll over, find midline, reach for objects, puts objects in mouth, coos (these are vowel sounds), and laughs
Fat Happy Baby: baby is rolling and laughing and cooing because he just discovered midline and is reaching for cake that he will cram into his mouth

6 months: sit up with no head lag, raking grasp, transfer objects between hands, babbles (consonants), recognizes familiar faces
Street-Corner Baby: sitting up on sidewalk, transferring a rake from hand to hand while babbling at people he thinks he recognizes

9 months: Crawl, pull to stand, point, specific babbling (mama, dada), stranger anxiety
Watch Dog Baby: crawls to window, pulls to stand to see out, points at stranger in yard and says “mama” to get attention of parents.

12 months: Walk, pincer grasp, 1 word, patacake, bye bye, peekaboo
Playful Zombie Baby: walking at you, snapping pincers, repeating one word over and over (brrraaaaains), and just wants to play patacake and peekaboo before waving bye bye.

15 months: walks well, imitates, controlled release of blocks (can stack 2)
Little Sister Baby: wants to be just like big sister, walks confidently to the blocks and imitates making a 2 block tower

18 months: Throw, scribble, 4 block tower, 1 step command, uses spoon/cup, points to parts of body
Sir Charming Baby: needs to get note to Rapunzel so scribbles note on paper to throw into high 4 block tower, catapult has cup on end, shoves note in with spoon, and throws note at tower, hitting Rapunzel in the face

2 years:  Run, stairs (1 foot at a time), 20-50 words, 2 step command, parallel play
Bad Twins: mom gives two commands to twin boys to run to the stairs, then walk up the 25 stairs. Each walks up the 25 stairs not helping the other.

3 years: Jump, Tricycle, dresses self (shirt, pants, shoes), full name, “you, me, I”
James Bond Baby: springs into action . . . jumps into 3-piece suit, stands in front of mirror and says full name, jumps on tricycle. “You.Me. I,” is his pickup line.

4 years: Stairs (alternating feet), hop, undresses, 1 foot (4 seconds), 4 word phrases (complete sentences), cooperative play
Bedtime Story Baby: really wants story time, so runs up stairs, hops on one foot to undress, so she and mom can read a story together. A Wrinkle in Time.

5 years:  Skip, Tie shoes, Difference between reality/fantasy
Oz Baby: ties ruby shoes, skips down Yellow Brick Road back to Kansas

Review of Approach to Memorization
1. Learn ages of well child checks from birth to 5 years. It’s not important to memorize in and of itself, but will really help you keep milestones and vaccine schedules straight:
-be able to rattle off all the checks (2, 4, 6 . . . remember 2-5 years are only annual checks so you really only have to memorize up to 2 years old)
-a flash card is helpful for this, just know it cold.
2. Learn associated gross motor milestones for each visit (make sure you understand the physiologic basis for the gross motor milestone progression as it will help you figure things out if you ever forget a particular milestone for a given month and can only remember the milestones around that month)
-flashcards helpful
3. Learn the archetype baby for each age (make sure you can visualize everything that baby is doing, the more vivid the picture, the faster you learn it, the easier it is to retain, and the faster you will be able to recall the milestones)
-again, flashcards helpful
That should do it! Knock this stuff out early in residency so you can move on to learning more conceptually difficult stuff. Here is a few examples of how you’ll see it during your education.

Example of questions you will see on boards:
You are seeing a 6 month old boy for his well child check. He is smiling at you, very talkative (no intelligible words), is able to pick up a block and change it from hand to hand, and has just started rolling over. At this time is he developmentally appropriate?

Example of how attendings will pimp you:
1. Can a baby roll off the bed at 3 months old and hit head of floor like mom is saying? (assessing for abuse) – no, this milestone only comes in at 4 months, a 3 month old should not be able to do this so your concern for non-accidental trauma is increased (though not definitive as some kids mature faster)
2. What would you expect this 9 month old to be able to do?

How this is used in clinic?
A mother brings her 11 month old concerned that he has not started talking at all and still cannot walk. What do you tell her?

Hope this helps.

Wednesday, September 19, 2012

Learning the Heart

When you're learning the path blood takes through the heart, start with blood leaving the left ventricle. This makes more conceptual sense and will help you get things straight. Learning the heart is like learning anything else in medicine, it is not hard or complicated, but it can quickly become overwhelming if you don't have a good  framework to put information into. So here's a broad framework for understanding the heart and the blood-flow through it.

The heart is one of the most important organs of the body. All organs have a function, all are important, but the heart and the brain are the two most important because without them everything else dies. And the body knows this. When a patient is really sick or losing a lot of blood, the body will start cutting off its own blood-flow to the parts of the body that it thinks are less important for immediate survival like the arms and the legs. This happens so that there is more blood for the heart and brain to use. 

The reason the heart is important is because of its one function: to deliver oxygen to the rest of the body. To digress a moment:

  • oxygen is needed for every cell (which is the building block of every part of our body) to make energy to function (this energy is called ATP)
  • if the oxygen supply is cut off, even for a brief amount of time, cells start to die which means our body starts to die
  • so getting a constant supply of oxygen to every part of our body is required for us to live (oxygen is to the body what oil is to the world's economy: if oil were cut off, even for one day, we'd be screwed. Same goes for oxygen except we're talking seconds to minutes)
  • Red Blood Cells is the part of our blood that carries oxygen from our lungs to the rest of our body; this is it's only important function. RBC = oxygen.

So again, the heart's one major function is to pump blood which contains the oxygen to the rest of the body. This happens when the left ventricle fills with blood just back from the lungs and shoots it out into the aorta and beyond. This is mission accomplished for the heart.

So the blood goes to different organs and your fingers and wherever and drops off the oxygen. It then returns to the heart to pick up more oxygen. The blood collects in the right side of the heart, is squeezed through the lungs where it picks up more oxygen, and again collects in the left ventricle, ready to get shot out again to carry more oxygen. Our body, like our economy, is very demanding for its natural resources. 

Get this broad concept down and think about blood flow through the heart as starting with expulsion from the left ventricle (oxygenated blood = mission accomplished) and follow it from there. It's a small thing but in my experience helps keep the later details straight.

Tips for Learning and Using Medical Terms

You're constantly told when you enter the healthcare field that it's like learning another language. This is, unfortunately for many of our future patients, very true. We learn medicine using many new terms that most of us do not understand when we start. Over time we get more used to them and start using them more easily, like learning any new language. Many of these new words are necessary because we're delving into a very specialized subject area that requires new words and new ways of communicating. However, a number of these words do not add deeper or new meaning to words and are used out of tradition. Diaphoresis means sweating. That's it. Emesis means vomit. That's it. These words you will learn and will become part of your everyday vocabulary. Just remember that most of your patients will not understand these words so you've got to be good about re-translating your words back into normal English.

One good way I've found for both learning new medical terms and guarding against poor patient communication is to learn exactly what each new word means. Literally. This is great in the age of internet because all you have to do is type etymology (etyomon = true sense; logy = a speaking) and then the medical word into google. Learning the origin of these words gives a sense of history to medicine and will also help these words stick with you better. An added bonus is when you start using these words, you'll know exactly what you're talking about. Many times we start using these words out of imitation and do not know exactly how to use them properly. This usually doesn't matter but can lead to confusion down the road when you're trying to build on your knowledge base.

Here are a couple good websites to help you in this endeavor:

Emory University has compiled a large number of commonly used medical terms and their origin. Alphabetical but no index.

The Online Etymology Dictionary. Concise, easy to navigate, and comprehensive.

Suggestions for Learning Blood Vessels

Gross Anatomy classes like to test on individual arteries and veins. There's a lot to choose from so it means easy questions to write but painful questions to prepare for as you pore over lists of weird sounding vessels with little understanding of why any of this matters or why you should care (apart from passing tests). At least this was my experience.

A few tips:

1. As I said in the previous post, start charting out arteries from the aorta and chart out the veins from one of the vena cavas depending on if you're learning things above or below the heart. Working out from these structures will really help you organize all this information because all arteries/veins are branches/twigs off the trunks of the big vessels.

2. If the name is weird, google it and figure out what it means or why it is called what it is called. Doing this makes the names less daunting and easier to remember. This is a good idea for every latin or greek medical term you don't know the meaning to because a lot of these names are simple descriptions and it's cool to know where these names came from. It gives a sense of history and insight into how people viewed things in the past.

3. Make a simple line drawing of the branching of the vessels. Pictures painted by Netter or other common sources are very detailed and do a great job of depicting what vessels look like in the body. However, when you're trying to learn the branches, all this extra visual detail is distracting and you can lose the fact that each vessel is really just a simple straight line. So draw it out, make it simple, and then when you get the basic connections you can go back and look at all the pretty pictures. Conceptually, all you really need to remember is the basic lines. Any other anatomic detail is best done on review after you've got the major geography down.

Hope this helps.

Suggestions for Learning MSK Anatomy

In most anatomy classes will have you memorize bones, muscles, nerves, and arteries/veins. It can be a lot of facts to absorb so here are a few good ways to approach it so that it makes more sense and is easier to learn/retain. The first time I tried to learn this was my second year of med school and I ended up trying to memorize lists of structures. It was difficult. It was boring. I retained next to nothing. Second time through I learned it for a sports medicine rotation and realized this stuff is pretty straight forwards. It's all basic, basic mechanical engineering

So here's a good plan of attack, starting with the order you learn things.

1. Learn anatomy by major joints. For the leg, learn hip first, then knee, then lower leg/ankle, then foot. For the arm, learn the scapula/shouler, elbow, wrist/hand. Joints are where muscles do their job so this is where they matter.

2. Learn the bones first

  • Just get a basic idea of what the bone looks like and to which other bones it connects to
  • Do not worry about each little detail at this point, just big picture, little details will make way more sense after you've learned the muscles so just skip them for now
  • Example: when learning the knee, get a basic idea of the humerus, tibia, and fibula (the only three bones around) and where they connect. Worry about ligaments later, we're just getting a general outline at this point.

3. Learn the muscles next

  • This is where the money is in terms of why we care about this anatomy. Muscles are what move us around and they are what often get pulled and torn and take people in to see the doctor
  • Organize the muscles into categories based around what they do. Each joint has a maximum of 6 movements that you care about and most have fewer. The six movements are flex, extend, abduct (move away from body), adduct (bring toward body; "add to body"), rotate in, rotate out. Figure out which movements the joint you're studying does and then figure out which muscles do each movement. Most movements have multiple muscles doing them.
  • Organizing muscles by which movement they do will help with organization, but will also help with later stuff because if they're doing similar actions, chances are they are in similar places and have similar nerve and blood supply. Also, this is how doctors think about muscles when they're diagnosing injuries.
4. Learn the nerves
  • Learn nerves by which group of muscles they serve and what action they make the body do. Do not worry about the exact path they follow through the body right now. Again, it will make more sense after you have a better global understanding of the anatomy and will just bog you down at this point.
  • For example: when learning the wrist, know the radial nerve is what causes the wrist to extend because it connects with the muscles of the top of the forearm. Also just memorize (if you have to) at what level this nerve leaves the spinal cord.
  • So learn where a nerve starts, where it ends, what action it does, and what muscles it connects to. Come back after you've got all this down and then learn details about the exact course they follow. It will make a lot more sense later on.
5. Learn the arteries/veins
  • When learning arteries or veins at any time, always start from the beginning and chart them out from there. That usually means starting at the aorta and branching out from there for arteries and either the superior vena cava or inferior vena cava for veins. This may seem like overkill but there are actually only a few major vessels and everything else branches or flows into these. If you do this you will get a much better conceptual idea of where all these branches come from which will make it seem less daunting a task to remember and will help you retain this all a lot better. Also, this will help you think about medical problems in a much clearer way.
That's it. The MSK system can seem daunting if you're learning from an excel spreadsheet listing individual muscles, their innervation, their blood supply, and their action. But if you can approach these in a rational way, you'll find that though there are a lot of facts, this stuff is not complicated and actually interesting.