Sunday 16 October 2016

No antibiotics for outpatient management of uncomplicated diverticulitis?


A long standing dictum in medicine is the mandatory treatment of acute diverticulitis with antibiotics. However there are now a couple of clinical trials proving that many cases of uncomplicated disease will recover with supportive care alone.

But before we alter our practice, it would be nice to see several studies of high quality evidence providing us a foundation for change. This paper certainly is not high quality evidence but it does add to the body of literature building out of Europe.

This was a descriptive study conducted in two Swedish hospitals that followed a convenience sample of 155 patients diagnosed with CT proven uncomplicated diverticulitis. They were managed without antibiotics and followed up as outpatients.

The mean age of patients was 57 and the mean CRP was 73. The majority had their first presentation of diverticulitis.

How successful was this strategy?

97% did just fine and recovered without complications... wow.

Of course there are some problems with this study design (selection bias, no comparator group, silly power calculation, unnecessary inferential statistics, etc) but it is compelling.

Sure, the literature is starting to look more definitive on this subject, but I’m not sure I have the cojones to change my practice quite yet... call me a eunuch.

I could only imagine having one of my patients return as a failure and have a surgeon castigate (castrate?) me.  In addition, I’m not sure this is the time & place to be making a substantial impact on antibiotics stewardship. Think URTI’s, bronchitis, otitis media, chickens...

I think it’s looking like antibiotics do have some minor effect. The number needed to treat for acute uncomplicated mild disease is probably somewhere between 30 to 50. This might be enough reason to continue our current practice. But, I could be proven wrong.


Saturday 15 October 2016

The 4-way range of motion test to exclude elbow fractures; the Sacramento Elbow Rules?

All kinds of clinical decision instruments have been sprouting up over the past few decades. Perhaps the most famous are the “Ottawa Ankle Rules” dating back to 1992.

There have been several attempts at a decision instrument for the elbow and this is probably why this latest offering was published in a lesser impact journal. Nevertheless, this version is quite promising.

The authors sought to prospectively validate their “4-way range of motion test" for the elbow.

(As an aside... there is no doubt that the lead author Dr David Vinson is a clever dude, but I think he may have failed in the marketing department. Nobody is ever going to remember the “4-way range of motion test,” nor is it very catchy.  So I’m going to call it the Sacramento Elbow Rules until he can think of something better.)

They enrolled a convenience sample of patients 5 years and older with an acute blunt elbow injury if the clinician felt that x-rays of the elbow were indicated. They assessed the performance of the rules compared to the gold standard diagnosis of a fracture or effusion seen on plain radiography.

The 4-way range of motion test... woops, Sacramento Elbow Rules are:

  • Full extension to 0°
  • Flexion to 90°
  • Full supination (with arm flexed at 90°) 
  • Full pronation (with arm flexed at 90°)

If the patient could not perform any one of the manoeuvres, they were considered to have failed the rules, thus requiring an x-ray. (To be clear, all patients got x-rays for the purpose of this study.)


They included 251 patients in their analysis. There were 99 positive x-rays. The test had a sensitivity of 99% (95% CI, 94-100%) and a specificity of 60% (95% CI, 54-69%). This is pretty darn good.

There was one false negative in a 7 year old boy with an undisplaced supracondylar fracture.

It is refreshing to see a paper with such an excellent discussion section. The authors suggest their rules may not be perfect as the lower level of confidence interval (CI) for sensitivity is not as high as 97%. But they wisely mention that a much larger study to narrow down the CI would be challenging and fail on feasibility. What we have is probably good enough especially since a missed subtle fracture is probably of lesser consequence than other high risk clinical scenarios.

I agree. This is probably a decent piece of information that should aid the clinician. It also passes the sniff test (face validity). If a patient can fully extend, flex and supinate & pronate then they probably don’t have a fracture. I’m willing to believe this. No rule is perfect but I think this is ready for prime time. 

Bring on the Sacramento Elbow Rules!


Clearing the C-spine in intoxicated trauma patients. Is a negative CT good enough?

Wouldn’t it be nice to remove the cervical spine collar in an intoxicated trauma patient after negative CT? No more thrashing around, shouting and hassle...

These physician assistant authors out of Portland, Oregon enrolled 1668 adult patients with blunt trauma who underwent cervical spine CT scans in their level 1 trauma centre.

632 (44%) of tested patients were found to be intoxicated. (Intoxication was deemed to positive if the BAL was greater than 0.08g/dl or a positive urine drug screen... ok, not perfect.)


In these intoxicated patients, the CT missed 5 patients with clinically relevant injury. 4 patients had central cord syndrome and one had an unstable ligamentous injury. All of these patients had obvious neurologic deficits and underwent MRI.

The authors conclude the CT had an overall negative predictive value of 99% for injury. Therefore spine clearance based on a negative CT in intoxicated patients with no gross motor deficit appears to be safe and avoids prolonged and unnecessary immobilization.

My heart wants to believe this conclusion but unfortunately there are some major methodological issues with this paper.

The biggest is incorporation bias. The way they identified cervical spine injury was mostly by CT. So of course the CT will have good test characteristics when it forms a substantial part of the gold standard. Only a minority of patients got MRI’s and clinical status was only followed to discharge. It is quite possible that injuries were missed or declared themselves later.  

The authors seemed to emphasize the negative predictive value (NPV) of the CT. But in cohorts with low prevalence of disease, the NPV always looks good. In fact, the NPV before doing anything was 90%.

A better test characteristic that does not depend on disease prevalence is sensitivity. Obviously it is important for screening tests to be highly sensitive especially when the stakes are high.

What was the sensitivity of the CT?

Only 92%. 

Some might argue that this is not good enough and this paper actually proves the opposite of what it is trying to conclude.

Let the controversy continue!


Thursday 13 October 2016

X-ray negative ankle sprains in children. Could this be an occult Salter-Harris fracture?

A child has sprained their ankle.  X-rays are negative but they have tenderness over the growth plate. 

This is an occult Salter-Harris I injury and they must be treated as a fracture!

Not anymore.

These authors out of Canada sought to determine the frequency of these occult injuries by performing ankle MRI’s in 135 children between the ages of 5 to 12 who had negative plain radiography.


Only 4 out of 135 (3%; 95%CI 0.1-5.9%) had occult Salter-Harris injuries! Turns out they are pretty unusual.

But there was an even more interesting finding in this study. The MRI discovered all kinds of unanticipated injuries despite negative x-rays:

80% with ligamentous injury (ok... no surprise here as they were sprains)
80% with “bone contusions” (goodness this sounds bad)
34% or one third had distal fibular avulsion fractures! (This sounds worse!)

Did patients with these occult injuries fare worse?


They had the same recovery time as those without these injuries. (But I must clarify that all kids in this study were treated with a “removable air-stirrup brace” as this was in keeping with current practice at participating institutions. Sounds like voodoo medicine to me.)

This goes to prove that the great microscope of the MRI will demonstrate a multitude of findings that probably have no clinical importance. This is better known as overdiagnosis. The major problem with overdiagnosis is clinicians may feel compelled to act (i.e. “overact”) on these findings.

What should we take home from this study?

Occult growth plate injuries after a simple sprain in children is pretty rare. You can probably treat them as a sprain.

MRI’s find all sorts of things that we probably don’t want to know about. Even worse, they may cause harm from overdiagnosis.