Sunday, September 20, 2009

Bone Age

Know the meaning, uses, and limitations of bone age

I find it fascinating how bone show our age, nutritional status, and fitness. When we're young, a lot of your skeleton is not made of bone yet, it's made of cartilage, which grows and then is replaced by bone. Based on x-rays, usually of the wrist and hand (convenience), the radiologist can either compare your bones with standard, healthy, films of bones of various ages, or use a complex formula to do the same thing. This is usually done when a young person isn't growing as expected, and we're looking into the cause. As we age, films show us bone density, which is a complex result of heredity, nutrition, and exercise. At any point in life, though, if you are nutritionally in trouble with your calcium and phosphorous, your bones are less dense, and this can be seen radiographically.

What are some drawbacks. Firstly, radiation. Secondly, if a radiologist is in a hurry and just glances at your films and the control films, the estimate of your bone age can be off by quite a bit, so you want a methodical person who's done this before to read your films. Lastly, the controls were white with good socioeconomic standing. Genetically, some of us may age more quickly or slowly and still be "normal", so this is a matter that still needs looking into.

Abbreviations: DEXA

Reference: Willenborg, A. Bone Age. Pediatrics in Review (1993) vol. 14 (4) pp. 133

Sunday, August 9, 2009

Not Blowing Hot Air: Ear Infections

Know that acute otitis media in the first six weeks after birth requires careful evaluation and follow-up
Know that pneumatic otoscopy is the preferred generally available method of diagnosing middle ear effusion because dimished tympanic membrane mobility usually accompanies middle ear effusion
Know the clinical manifestations of acute otitis media:fever may or may not be present, otalgia, nonspecific symptoms (eg, irritability)

When I look into a child's ears to determine whether or not she has an infection of the middle ear, I'm supposed to use my instrument to blow a puff of air onto the eardrum. If it flexes normally, all is well; otherwise a lack of compliance suggests fluid there: but is it infected or not?.

The strict criteria for an ear infection as opposed to just having fluid in the middle ear includes three things 1) acute onset 2) an exam consistent with having middle ear fluid and 3) signs of inflammation there. The onset is usually pretty easy, but fluid that is not infected can accumulate rapidly as well, and uninfected fluid can hurt. Signs of inflammation are rampant, being either pain or redness: most children come in for ear pain, and one good cry is enough to make the eardrum as red as the child’s face. The exam for a middle ear effusion should be fairly easy, but with a frantic child in pain, it is often technically difficult. Wax gets in the way, the child moves, and curiously enough, our clinic doesn’t have any of the insufflation bulbs required to check ear drum compliance. When pus comes draining out of the ear (a sign of middle ear fluid), I sometimes heave a sigh of relief and get ready to write for some medicine.

I really like the AAP guideline’s little chart for diagnosing an ear infection, so I’ll reproduce it here:

A diagnosis of AOM requires 1) a history of acute onset of signs and symptoms, 2) the presence of MEE, and 3) signs and symptoms of middle-ear inflammation. Elements of the definition of AOM are all of the following:
1. Recent, usually abrupt, onset of signs and symptoms of middle-ear inflammation and MEE
2. The presence of MEE that is indicated by any of the following:
a. Bulging of the tympanic membrane
b. Limited or absent mobility of the tympanic membrane
c. Air-fluid level behind the tympanic membrane d. Otorrhea
3. Signs or symptoms of middle-ear inflammation as indicated by either
a. Distinct erythema of the tympanic membrane or
b. Distinct otalgia (discomfort clearly referable to the ear[s] that results in interference with or precludes normal activity or sleep)

Abbreviations: TM, AOM, OME, MEE

Reference: American Academy of Pediatrics Subcommittee on Management of Acute Otitis Media. Diagnosis and management of acute otitis media. Pediatrics (2004) vol. 113 (5) pp. 1451-65.

Teaching Students How To Consult Specialists

I subscribe to several medical Twitter feeds, ones that are 1) useful 2) have a readable frequency of posting 3) and are relevant.

Thanks to the feed by "Dr. Ves", I found a cute survival guide written for first-year general practitioners in the United Kingdom. Now their medical education system differs from ours significantly, as well as their whole funding, but I was excited to find this new mnemonic: SBAR.

Situation: I am [med student, resident, doc] on [the general inpatient service, the urgent care clinic, the pediatric clinic], and I need your help with [x].

Background: give patient's age, reason for presentation to your service, current status, problem, relevant history and exam, relevant labs, etc.

Assessment: I think the problem is x

Recommendation: I want to do this, what would you recommend. OR I need you to see them.
(Record: record your conversation, the plan, and if they are consulting, the time frame)

I like that it gives a nice framework for students to think about speaking to a consultant. Oftentimes we tell them "call nephrology", and they are awkward and incomplete on the phone, despite coaching. However, this acronym, SBAR, is entirely new to me, and I find it hard to remember. Another acronym and mnemonic SOAP, is a framework we teach for writing notes, and it also appears in the guide for new physicians. Notes, it appears, are universal. It will be easy and convenient to remind students of what they know and frame their call to the consultant in a SOAP format.

Subjective: how is the patient doing, what brought them in, what are their concerns
Objective: background/history, age, labs, exam
Assessment: as above
Plan: as "recommendation" above

Abbreviation: sbar, UK, soap

Tuesday, August 4, 2009

Vegetarianism and Other Weighty Matters

Recognize that nutritional deficiencies may develop in infants who are fed nontraditional diets (eg, goat milk, vegetarian)

Minh is currently a lacto-ovo-vegetarian. I did cheat twice with some bits of my ham sandwich and some chicken, but other than that he's not had meat. My main reason is that I think it's healthier, and I don't want to change stinky diapers. The fruity ones are bad enough. Eeew.

Anyway, Minh's weight percentile has dropped since I started working again when he was six months, and while he doesn't look like a refugee, just slender, I worry because I'm his mom. According to a recent Peds in Review article co-authored by a medical school classmate of mine, Minh is probably getting adequate B12 from his diet, since he consumes eggs every morning. He is also likely getting adequate protein, as most vegetarians consume more than the minimum amount of protein. He was tested at 6 months for anemia, and his hemoglobin level was fine, so I'm not as worried about that. A lot of vegetarians eat high-fiber, low calorie diets, though, and that may be Minh's problem.

Now, if he were vegan, I would at this time be worried about his B12 levels, as well as calcium, folate, iron, and zinc. Right now, though I think that I just have to introduce him to more fatty foods, and foods that have omega 3 fatty acids. I'm thinking greek yogurt and tofu right now. I've got the Moosewood Collective cookbooks I like out in front of me, and I'm planning on vegetarian mayhem tonight.

Abbreviations: FTT

1. Renda and Fischer. Vegetarian Diets in Children and Adolescents. Pediatrics in Review (2009)

2. Goat's milk sounds like something you need to know about for the boards and nowhere else. Here's a comparison from people who sell goat milk (keep that in mind).

Monday, July 6, 2009


I've just spent several hours going over a Pediatrics and Review article about incontinence. I spent some time pondering it because the general message seemed to be that a lot of incontinence is secondary, you work it up with a urine analysis and culture, and you treat most secondary incontinence with behavioral modification and a bowel regimen. In the end, though, it goes off the deep end talking about various types of daytime wetness (no longer called diurnal enuresis), and how some of them can progress to eventual renal failure.

Finally, I looked up the renal section in my trusty board review book...and it's not even mentioned. Must not be important on the boards. Still, a lot of parents come in for incontinence involving stool or urine or both. So it was useful. I think that in the future, I will a) do an H and P b) get a u/a, urine culture, and voiding bladder ultrasound to look at the postvoid residual, c) work the child up further if the postvoid residual is significant.

Abbreviations: U/A, UCx, PVR

Saturday, July 4, 2009

NICU Levels

While rounding with our Intermediate Care Nursery attending:

Which babies belong at which of our 3 nurseries (Neonatal Intensive Care Unit, Intermediate Care Nursery, Newborn Nursery)?

Generally, babies less than 34 weeks gestation go to the intensive care unit (Level III).

Between 34-37 weeks babies will go to a Level II feeder and grower unit, some CPAP may be allowed depending on the institution guidelines. Healthy late preterm babies may go to a Level I nursery at some institutions.

Healthy babies will go to a Level I unit. Some institutions may allow babies requiring a little oxygen to transition in a Level I unit.

Basically, each institution will have slightly different guidelines and levels of comfort. Assess the unit's ability to handle your patient and act accordingly.

Further Clarification:
1. Levels of Neonatal Care: PEDIATRICS Vol. 114 No. 5 November 2004, pp. 1341-1347 (doi:10.1542/10.1542/peds.2004-1697)

Abbreviations: NICU, ICN, NBN, preemie

Friday, May 22, 2009


While rounding with our newest pediatric pulmonologist:

The seven causes of hypoxemia
1. Low inspiratory partial pressure (fraction) of oxygen: high altitude
2. Alveolar hypoventilation: apnea
3. Impairment of diffusion across blood-gas membrane: pneumonia, interstitial disease
4. Ventilation-perfusion mismatch: asthma
5. Shunt: Arterio-venous malformation, mixing cardiac lesion
6. Reduced mixed venous oxygen content in the context of a shunt: not sure
7. Hemoglobinopathy: carbon monoxide poisoning

Abbreviations: FiO2, a's and b's, a-A gradient, dz, V-Q mismatch, AVM, CO, ddx

Sunday, May 10, 2009

Calcium Metabolism: Hypocalcemia

Recognize the signs and symptoms of hypocalcemia

Add this to your differential, guys: hypocalcemia generally makes you more prone to tetany, which is the term for muscle contractions due to neuromuscular excitability. Usually we think of tetany as sustained contractions in the hands, feet, or face, but hypocalcemia can also present as cyanosis or stridor from laryngospasm. So think about it the next time you see croup!

Abbreviations: ical, ca, ddx
Mnemonic: Low cash (Calcium) makes your face twitch (tetany)

Friday, May 8, 2009

Journal Club: Be Mean

Evidence-based medicine is a process. First, investigators test therapies against each other, against nothing, try different tests, frenzy themselves with recruiting patients for one study after another. Others follow after patients, trying to figure out if this sized liver is normal or if it goes bad in ten years. The various studies and types of studies pile up. Then, a clinician, with a patient, tries to read through it all and make the best decision for the individual patient. To do that she needs to be critical of the studies from conception to completion.

In residency, we try to be nice to each other. Life is tough; we try not to make it worse. We support growth and change and sometimes simple survival through the worst of the season. Today, though, I learned that when it comes to studies, I need to be mean.

Abbreviations: EBM

Persistent Sleep Apnea after Tonsillectomy & Adenoidectomy

While rounding with one of our pediatric pulmonologists:

It often takes 6-8 weeks before someone with obstructive sleep apnea recovers enough from tonsillectomy & adenoidectomy to be eligible for repeat sleep study. Follow-up with pulmonology in two months. If they had problems with low oxygen saturation overnight, consider discharge with home oxygen for sleep, though then they will need to have a sleep study to document that they can stop that.

Abbreviations: T&A, OSA