Which Pediatric Seizure Patients Require a CT?

September 2008

Which Pediatric Seizure Patients Require a CT?

Search Strategy: 2 search strategies were used. First, we searched OVID with the keyword: seizure. Using the explode subheading option, we chose radiography and then limited the data set to all child aged 0-18 years. This yielded 34 studies, 2 of which were selected. There was one article from an Iranian journal that was used to find similar articles. A single article was chosen in this way. An additional study was selected by using a similar search strategy with the keywords: febrile seizure and neuroimaging. This strategy yielded 9 articles. The first was chosen for review. In addition, the AAP Practice parameters for both febrile and non-febrile seizures were reviewed. No additional articles were found for review.

You are working an overnight shift in the Pediatric ED at SLCH when EMS arrives with a 26 month-old infant who is actively seizing. Per the family the seizure started 5 minutes prior to EMS arrival and involved the whole body shaking. He has now been seizing for at least 20 minutes. The child had been well until today, when he developed clear rhinorrhea and a tactile fever. On your examination, you note the following:

VS: T 38.0 RR 20 HR 165 BP 95/60 Sats 100% on NRB O2 mask All extremities are extended and eyes are deviated to the right. There are no signs of trauma and the rest of the exam is unremarkable.

You establish an IV and administer lorazepam intravenously with cessation of the seizure activity. You are now ready to proceed with your diagnostic evaluation. Your attending asks you if you are considering a head imaging study. You reflect on the recent Journal Club you attended and thoughtfully reply, “……”


PICO Question

Population: Pediatric patients with new onset seizure

Intervention: Neuroimaging study in emergency setting

Comparison: No neuroimaging in emergency setting

Outcome: Need for emergent intervention


Years

First years: Predictors of Abnormal Findings of Computed Tomography of the Head in Pediatric Patients Presenting with Seizures, Ann Emerg Med 1997; 29: 518-523. (http://pmid.us/9095014)

Second years: Emergency Brain Computed Tomography in Children with Seizures: Who Is Most Likely to Benefit?, J Pediatr 1998; 133: 664-669. (http://pmid.us/9821426)

Third years: The Role of Emergent Neuroimaging in Children with New-Onset Afebrile Seizures, Pediatrics 2003; 111: 1-5. (http://pmid.us/12509546)

Fourth years: Risk of Intracranial Pathologic Conditions Requiring Emergency Intervention After a First Complex Febrile Seizure Episode Among Children. Pediatrics 2006; 117: 304-308. (http://pmid.us/16452347)


Articles

Article 1: Predictors of Abnormal Findings of Computed Tomography of the Head in Pediatric Patients Presenting with Seizures, Annals of EM 1997.pdf
ANSWER KEY

Article 2: Emergency brain computed tomography in children with seizures: Who is most likely to benefit? J Pediatrics 1998.pdf
ANSWER KEY

Article 3: The Role of Emergent Neuroimaging in Children with New-Onset Afebrile Seizures, Pediatrics2003.pdf
ANSWER KEY

Article 4: Risk of Intracranial Pathologic Conditions Requiring Emergency Intervention after a First Complex Febrile Seizure Episode among Children, Pediatrics 2006.pdf
ANSWER KEY


Bottom Line

Pulmonary embolism (PE) is an elusive diagnosis that occurs in 1-2 individuals per 1000 persons in the United States each year. Patients diagnosed with PE in the emergency department have an overall low mortality (1% attributed to PE) and high functional status. PE can present with a variety of symptoms (dyspnea, chest pain, palpitations, syncope) and most patients with these symptoms do not have a PE. Unfortunately, the diagnosis of PE using clinical findings alone is inaccurate (Hoellerich 1986, Moser 1994, Hampson 1995). Although there is a role for clinical gestalt in experienced physicians, clinical prediction rules (such as the Well’s criteria described below) should be used based upon overall accuracy and the potential to reduce test ordering variability particularly amongst less experienced clinicians. However, many physicians fail to use these decision aids such as the Well’s Criteria or PERC rule while assessing for PE.

In contemplating the diagnosis of PE, clinicians are balancing the risks of missing the often fatal PE against the radiation risks (and sometimes logistical risks of transferring patients to tertiary centers where the technology is available) of V/Q or CT pulmonary angiography. Here are two epidemiological facts to consider. One large database suggests that only 1.4% of patients evaluated for PE will ultimately be diagnosed with ACS. And lower extremity Doppler are not a reasonable first-line screen for PE since emergency physicians do not suspect DVT in 90% of PE patients.

ACEP Guidelines (circa 2003) recommend that Well’s criteria (below) or similarly validated decision aids like the Wicki criteria or Kline criteria should be used prior to test-ordering to risk stratify ED patients with suspected PE. Once PE probability stratification is deduced, use of quantitative D-dimer (ELISA or turbidimetric) can exclude patients with low pre-test probability. In low to moderate pretest probability patients, a normal V/Q scan excludes clinically significant PE. The 3-month risk of DVT or PE in patients with a negative spiral CT is 0.5%. Updated ACEP Guidelines have been written but await ACEP Board of Director approval and have not yet been published. The new guidelines will hopefully provide evidence-based recommendations for the use of emergency physician-performed DVT ultrasound, the role of the PERC score to avoid preventable false-positive D-dimer testing, as well as the indications for repeat imaging in patients with known PE who frequently present to the ED with potentially related complaints.


Well’s Criteria

Risk Factor Points
Suspected DVT 3
Alternative Diagnosis Less Likely than PE 3
Heart Rate > 100 1.5
Immobilization or surgery previous 4 weeks 1.5
Previous DVT or PE 1.5
Hemoptysis 1
Malignancy (last 6 months or palliative) 1
Score Mean Probability PE (%) % with this Score Risk Interpretation
0 – 2 points 3.6 40 Low
3 – 6 points 20.5 53 Moderate
> 6 points 66.7 7 High

Several risk factors that are not currently part of validated clinical decision rules can increase (thrombophilia, pleuritic pain, family history of VTE) or decrease (substernal pain, current smoker) the probability of PE when contemplating test-treat thresholds. V/Q scanning should still play a role in the diagnostic evaluation of PE. Although based upon 3-month outcomes (death or new PE or DVT) suggests no differences between a normal V/Q or nondiagnostic V/Q + negative LE ultrasound with Wells score <4.5, clinicians are less accepting of V/Q than CTPA. In addition to the radiation-risk and contrast-dye adverse side effects, clinicians should be aware that a portion of PE’s diagnosed by CTPA may be clinically inconsequential as evidenced by the lower overall PE detection rate in the randomized sampling of the PGY IV article with no increase in mortality or morbidity.

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