To scan or not to scan?

[GeneralVeers]

Scenario: 14 yo hispanic boy with 3 days of worsening headache, vomiting, and lethargy. Per mom he doesn't even want to watch TV anymore. The kid complains of a headache, and that his neck hurts. Physical exam reveals fever, but no neurologic findings, with fundoscopic exam normal.

Obviously this kid needs an LP.

My understanding from reading (Tintinalli) is that you can use your clinical judgement to determine whether or not to run this kid's head through the CT scanner first. Indications for scan are listed as seizure, focal neurologic deficit and papilledema, none of which this kid has.

So we go ahead and do the LP, treat the kid empirically and admit him to peds.

The next morning there are two pages on my pager from the attending who was pissed off because I didn't pre-scan the kid before doing the LP, and he wanted to wake me up to yell at me on the phone. Fortunately once I go home I don't answer my pager.

BTW CSF came back and showed aseptic meningitis.

So my question is, was it wrong for me not to pre-scan the kid? I'm certain I will have this argument with said attending the next time I work a shift with him.

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[mikecwru]

It's perfectly acceptable to tap and not scan the child as you did. I would add on to your list of "requirements" that the person not be immunosuppressed. That's the academic answer. And your tap revealed the diagnosis. The only question is would you have left it at that if the tap was negative (what about a mass w/o papilledema just now declaring itself; what about ischemia/bleeding in the posterior fossa?)? In reality, I often scan these kids because it's difficult to work serially like this in the emergency department, but in my head it's not to "clear" them for the tap.

Remember that a head CT in the total ED cost is not that much, is quick, and is fairly safe. The biggest thing that saves money in the ED is time; if you're able to dispo this kid that much more quickly by scanning, tapping him, you're able to see other patients. This is why I don't get upset when triage nurses order xrays when the ottawa rules may have applied, etc.

Hopefully this made sense when I'm half asleep.

mike

Scenario: 14 yo hispanic boy with 3 days of worsening headache, vomiting, and lethargy. Per mom he doesn't even want to watch TV anymore. The kid complains of a headache, and that his neck hurts. Physical exam reveals fever, but no neurologic findings, with fundoscopic exam normal.

Obviously this kid needs an LP.

My understanding from reading (Tintinalli) is that you can use your clinical judgement to determine whether or not to run this kid's head through the CT scanner first. Indications for scan are listed as seizure, focal neurologic deficit and papilledema, none of which this kid has.

So we go ahead and do the LP, treat the kid empirically and admit him to peds.

The next morning there are two pages on my pager from the attending who was pissed off because I didn't pre-scan the kid before doing the LP, and he wanted to wake me up to yell at me on the phone. Fortunately once I go home I don't answer my pager.

BTW CSF came back and showed aseptic meningitis.

So my question is, was it wrong for me not to pre-scan the kid? I'm certain I will have this argument with said attending the next time I work a shift with him.

 

[GeneralVeers]

It's perfectly acceptable to tap and not scan the child as you did. I would add on to your list of "requirements" that the person not be immunosuppressed. That's the academic answer. And your tap revealed the diagnosis. The only question is would you have left it at that if the tap was negative (what about a mass w/o papilledema just now declaring itself; what about ischemia/bleeding in the posterior fossa?)? In reality, I often scan these kids because it's difficult to work serially like this in the emergency department, but in my head it's not to "clear" them for the tap.

Remember that a head CT in the total ED cost is not that much, is quick, and is fairly safe. The biggest thing that saves money in the ED is time; if you're able to dispo this kid that much more quickly by scanning, tapping him, you're able to see other patients. This is why I don't get upset when triage nurses order xrays when the ottawa rules may have applied, etc.

Hopefully this made sense when I'm half asleep.

mike

Thanks for the response, it's definitely a reasonable answer. Several of the attendings here have an overly conservative approach to all patients. Basically when they are on, I know I have to order all labs, and scan every patient from head to toe before I can release them, regardless of complaint. If they're not teaching residents clinical decision making skills, I'm not sure how they expect us to function once we have to get real jobs.

 

[DrQuinn]

Add altered mental status to that list. It sounds like your kid was with it, albeit a little grumpy.

Agree with MikeCWRU, as you get further in your education, you'll realize part of running an ED is patient flow and dispo... had the LP come back negative you probably would have had to scan his head anyways, even though menigitis was teh highest on your differential.

I think in academia, the CT/LP rules apply a little bit more, but in the real world, CT is now becoming just like a "CXR". Years ago no one did CT's of the head, nowadays its so common place to just get one like you would a plain film. A CT of the abd/pelvis w/o contrast to search for stones costs as much as an IVP, and has the same amount of radiation.

Q

 

[tonem]

There was an interesting discussion by a "panel of experts" in this months EM: RAPS about this very topic....are we overscanning and overtesting patients unnecessarily? Some of the previous posts kinda echo their arguments. Another question is what is all that radiation doing to people's brains...and thyroids. The new generation multi-head, super-duper, can spot a PE in a capillary CT scanners are supposed to put out way more rads than the older models...

 

[southerndoc]

Quinn, a recent article in JEM (June I believe?) has laid the groundwork for eliminating the CT/LP route for suspected SAH. 5th generation scanners are obviating the need for LP's. In a few more years, even academic centers won't be LP'ing individuals with r/o SAH sentinel bleeds.

Veers, do a Medline search and show the pediatrician the evidence. Evidence only supports obtaining a CT scan prior to lumbar puncture if there is evidence of neurologic compromise. I'm quoting the abstract of research we did at my hospital that was published in 2001. Show that to your pediatrician (maybe forward a copy of the article anonymously to him/her).

Hasbun, R, et al. Computed tomography of the head before lumbar puncture in adults with suspected meningitis. NEJM, 345(24):1727-33.

BACKGROUND: In adults with suspected meningitis clinicians routinely order computed tomography (CT) of the head before performing a lumbar puncture. METHODS: We prospectively studied 301 adults with suspected meningitis to determine whether clinical characteristics that were present before CT of the head was performed could be used to identify patients who were unlikely to have abnormalities on CT. The Modified National Institutes of Health Stroke Scale was used to identify neurologic abnormalities. RESULTS: Of the 301 patients with suspected meningitis, 235 (78 percent) underwent CT of the head before undergoing lumbar puncture. In 56 of the 235 patients (24 percent), the results of CT were abnormal; 11 patients (5 percent) had evidence of a mass effect. The clinical features at base line that were associated with an abnormal finding on CT of the head were an age of at least 60 years, immunocompromise, a history of central nervous system disease, and a history of seizure within one week before presentation, as well as the following neurologic abnormalities: an abnormal level of consciousness, an inability to answer two consecutive questions correctly or to follow two consecutive commands, gaze palsy, abnormal visual fields, facial palsy, arm drift, leg drift, and abnormal language (e.g., aphasia). None of these features were present at base line in 96 of the 235 patients who underwent CT scanning of the head (41 percent). The CT scan was normal in 93 of these 96 patients, yielding a negative predictive value of 97 percent. Of the three misclassified patients, only one had a mild mass effect on CT, and all three subsequently underwent lumbar puncture, with no evidence of brain herniation one week later. CONCLUSIONS: In adults with suspected meningitis, clinical features can be used to identify those who are unlikely to have abnormal findings on CT of the head.

 

[docB]

I don't think you were wrong to not scan before the LP. I probably would have done it but you can certainly argue against it. The most crucial thing for these pts is that they get antibiotics as soon as you consider meningitis as a diagnosis. Everything else is secondary.
I'd say that the thing this illustrates best is how consultants get used to having their workups done for them. In private practice this only gets worse. Many consultants freak out if you want to admit a SOB without an ABG or a chest pain without a CT Chest ("But how do I know it's not a PE?" "Well, they'll be on Lovenox anyway and you can get the CT as an inpt." "Waaaaaaaa!")
The sad fact is that some of this come down to $$$. Hospitals lean on you not to order too much stuff (they call it "utilization review") and the consultants would rather the ER doc order it.

 

[southerndoc]

With the hospital cost for a CT being only $100 at most institutions, one can argue that the $1 million lawsuit for a herniation from an LP, missed bleed, etc. can buy you 10,000 head CT's.

Food for thought... but not supported by evidence.

 

[DrQuinn]

Quinn, a recent article in JEM (June I believe?) has laid the groundwork for eliminating the CT/LP route for suspected SAH. 5th generation scanners are obviating the need for LP's. In a few more years, even academic centers won't be LP'ing individuals with r/o SAH sentinel bleeds.

When I mentioned Ct/LP, I was referring to meningitis, not SAH. Thankfully, every patient who I suspected SAH had a positive CT (n ~ 20). I know that there is some research coming out now that the new scanners can obviate the need for LP (I did read that article a few weeks back). If on Oct 1st (when I go back to the ED, on an administrative rotation), I get a negative CT on a person with a likely SAH, I probalby will do an LP and pray to God for xanthochromia by spect... as, well, that's how its done here at my hospital.

Q

 

[NinerNiner999]

While time has been mentioned as a factor in ED flow, if there is SAH, the time to LP, get negative results, then wait for a scan can be detrimental. An article from Singapore evaluated 57 patients over three years with SAH, and neck stiffness accounted for 21% of the ED complaints, meaning that despite the probable meningitis that lead to an LP, there may still be a roughly 1 in 5 chance that a SAH exists.

Singapore Med J. 1999 Jun;40(6):383-5.

 

[southerndoc]

When I mentioned Ct/LP, I was referring to meningitis, not SAH. Thankfully, every patient who I suspected SAH had a positive CT (n ~ 20). I know that there is some research coming out now that the new scanners can obviate the need for LP (I did read that article a few weeks back). If on Oct 1st (when I go back to the ED, on an administrative rotation), I get a negative CT on a person with a likely SAH, I probalby will do an LP and pray to God for xanthochromia by spect... as, well, that's how its done here at my hospital.

Q

You guys do photospectrometry for detection of xanthochromia? Supposedly less than 5% of all labs in the US do that. My hospital doesn't use it. Now it seems like I can flip a coin to see if the LP is going to have xanthochromia given the recent research that showed a 25% sensitivity in detection of xanthochromia by visual inspection by lab technicians. With the coin, I at least get 50%!

 

[GeneralVeers]

I don't think you were wrong to not scan before the LP. I probably would have done it but you can certainly argue against it. The most crucial thing for these pts is that they get antibiotics as soon as you consider meningitis as a diagnosis. Everything else is secondary.
I'd say that the thing this illustrates best is how consultants get used to having their workups done for them. In private practice this only gets worse. Many consultants freak out if you want to admit a SOB without an ABG or a chest pain without a CT Chest ("But how do I know it's not a PE?" "Well, they'll be on Lovenox anyway and you can get the CT as an inpt." "Waaaaaaaa!")
The sad fact is that some of this come down to $$$. Hospitals lean on you not to order too much stuff (they call it "utilization review") and the consultants would rather the ER doc order it.

It wasn't the pediatrician calling me at home to wake me up. It was the ED attending who had just come onto shift as I was leaving!

 

[DrQuinn]

You guys do photospectrometry for detection of xanthochromia? Supposedly less than 5% of all labs in the US do that. My hospital doesn't use it. Now it seems like I can flip a coin to see if the LP is going to have xanthochromia given the recent research that showed a 25% sensitivity in detection of xanthochromia by visual inspection by lab technicians. With the coin, I at least get 50%!

Visual xanthochromia actually has up to a whopping 50% sensitivity. So you are indeed right, like flipping a coin. Crazy, eh?

Q

 

[colforbinMD]

Theres a study being done to see if an optic nerve sheath diameter by u/s could be used in lew of Head CT to detect incr. ICP before LP. Will be interesting to see the results.

 

[ERMudPhud]

The issue isn't the financial cost of the CT its the risk, particularly to children, of increased radiation exposure. All the CT's we are doing for belly pain in kids is of similar concern.

Brenner D, Elliston C, Hall E, Berdon W.
Estimated risks of radiation-induced fatal cancer from pediatric CT.
AJR Am J Roentgenol. 2001 Feb;176(2):289-96.
PMID: 11159059 [PubMed - indexed for MEDLINE]

Granted the numbers are theoretical but they estimate a lifetime risk of cancer mortality from 1 abdominal CT in a 1 year old of 1/500 and from 1 head CT of about 1/1000. My daughter had a head CT as a neonate for a suspected depressed skull fx secondary to birth trauma and to this day I still have what can best be described as mixed feelings about. If she were to come down with a CNS tumor my feelings would better be described as crushing guilt.

Show your attending the above reference and the NEJM reference mentioned earlier. Then just to really put a scare in him show him this reference.

Shetty AK, Desselle BC, Craver RD, Steele RW.
Fatal cerebral herniation after lumbar puncture in a patient with a normal
computed tomography scan.
Pediatrics. 1999 Jun;103(6 Pt 1):1284-7. No abstract available.
PMID: 10353943 [PubMed - indexed for MEDLINE]

Show him the textbook chapters that agree with all of the above. Then if he can't explain some specific reason why he thinks your patient should have been CT'd tell him to find a job where he isn't responsible for educating impressionable residents.

 

[sacrament]

With the hospital cost for a CT being only $100 at most institutions, one can argue that the $1 million lawsuit for a herniation from an LP, missed bleed, etc. can buy you 10,000 head CT's.

Food for thought... but not supported by evidence.

Indeed, our emergency department used to approach this problem by scanning any patient who presents with a symptom of any kind, in any organ system. The current protocol is to additionally scan all completely asymptomatic patients as well as anybody who walks by on the street.

 

[GeneralVeers]

Thanks for the references guys! I plan to print out the full articles and take them with me as ammunition for when this ED attending starts to lecture me on my stupidity.

 

[f_w]

> Per mom he doesn't even want to watch TV anymore.

This should have been a 'hard' indication to scan him ! )

I am glad that a discussion in the ED forum at least mentions the fact that radiation from CTs might not be all that good for kids after all. While all the 1:x ratios are higly speculative and extrapolated from data obtained at much higher levels, it helps to illustrate the potential danger. We do know one thing: If you have bacterial meningitis, neurologic outcome and time to treatment are closely related. So the 'safer' method of scanning everybody with meningitic symptoms before the tap actually will harm some patients.

Oh, one more thing. The marginal 'cost' of the CT to the hospital might indeed be only $100, for the patient an unneccessary CT turns a $450 ED visit into a $1000 trip. If if it is medically necessary, by all means scan whoever you want, but please, don't scan them as a matter of routine because you believe that it comes for free and helps your workflow (I can see the rationale of getting a plain-film of the ankle without prior physician assessment. The radiation dose is minuscule and in essence, the patient came 'to get an x-ray' anyway. CT otoh should not be performed on 'autopilot'.)

 

[docB]

It wasn't the pediatrician calling me at home to wake me up. It was the ED attending who had just come onto shift as I was leaving!

Then that's just painful.

This discussion points out how insidious the current med mal and defensive medicine climate is. I had seen the study about the greatly increased lifetime CA risk from a CT. However, as EPs we are more likely to get sued for something missed because we didn't scan than for the eventual CAs we cause with scan that weren't really indicated. And the only thing that can be done to stop the CYA type defensive medicine is to reform the med mal system.

 

[southerndoc]

Please note that in my post of CT'ing everyone based on financial reasons, I did mention that this is not supported by evidence (this is not a practice I support - I think everything should be evidence-based).

Regarding a $450 ED visit turning into a $1000 ED visit, I doubt a suspected meningitis will escape the ED for only $1000, with or without a CT. My ED bill was nearly $800 for lab checks to see if my CPK peaked when I had drug-induced rhabdo. A suspected meningitis, especially one that gets admitted, may very well get the highest ED bill. The LP procedure itself is charged to the patient for about $300.

 

[f_w]

The $450 turning into 1k was not necessarily meant to represent a case of suspected meningitis, but rather the general difference between an ED visit without CT scan and one with a non-indicated CT scan (e.g. kid gets hit on head with wooden toy. superficial abrasion/bruise, no LOC, no neuro deficit, nothing).

I don't care about money. If it makes medical (or even medicolegal) sense, go ahead and spend it (just yesterday I blew out $600 worth of equipment on a $25 procedure. The patient needed it, so who cares.). What I am concerned about is the idea of putting your patients interest below your departments monetary interest. And yes, you are right, the evidence doesn't support this practice either.

 

[bartleby]

Withhold empiric treatment (pre-tap) for a patient with a significant likelihood of bacterial meningitis at your own peril.

> So the 'safer' method of scanning everybody with meningitic symptoms before the tap actually will harm some patients.