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Neck computed tomography in pediatric neck mass as initial evaluation in ED: is it malpractice?

Open AccessPublished:August 02, 2014DOI:https://doi.org/10.1016/j.ajem.2014.07.031

      Abstract

      Background

      Although ultrasound is regarded as the first choice imaging modality for evaluating a pediatric neck mass, neck computed tomography (CT) is necessary for urgent surgical conditions such as deep neck infections. Our aim was to evaluate the diagnostic effectiveness of and proper patient selection for neck CT as a method for the initial evaluation of pediatric neck masses in the emergency department.

      Methods

      We analyzed the medical records of 105 pediatric patients who visited the emergency department with neck mass whose initial imaging work-up was a neck CT and who visited the emergency department with a neck mass. The parameters investigated included the patient’s age, sex, symptom duration, clinical impression, CT interpretation, final diagnosis, and treatment. The positive predictive value (PPV) for CT was calculated, and the parameters that correlated with an urgent surgical condition post-CT were evaluated.

      Results

      The median age was 6.5 years (1 month to 12 years), and the male-to-female ratio was 2:1. The most common initial impression was acute cervical lymphadenopathy. A comparison of the final diagnosis and CT scan demonstrated that the overall PPV was 96.2%. If the initial impression was a deep neck infection, a salivary gland infection, or tonsillitis, the PPV for CT was 100%. Fever (>38.0°C) and severe tenderness were significant between patients with and without urgent surgical conditions on CT.

      Conclusions

      Computed tomography could be considered as the first diagnostic modality when an urgent surgical condition such as a deep neck infection is highly suspected.

      1. Introduction

      Neck masses are common in children and are a frequent cause of visiting the emergency department. The most common etiologies include congenital lesions and their complications; lymphadenopathy; and vascular, inflammatory, and malignant lesions. Until recently, ultrasound (US) has been regarded as the first modality for investigation, as it is readily available and does not involve ionizing radiation, which computed tomography (CT) has, and does not require the sedation of infants as often as magnetic resonance imaging [
      • Faerber E.N.
      • Swartz J.D.
      Imaging of neck masses in infants and children.
      ].
      Computed tomography can be used to determine the extent of a mass and better define its tissue characteristics and anatomy, especially with urgent surgical conditions. The usefulness of CT with a neck infection, especially pediatric deep neck infections, has been demonstrated in numerous prior studies [
      • Endicott J.N.
      • Nelson R.J.
      • Saraceno C.A.
      Diagnosis and management decisions in infections of the deep fascial spaces of the head and neck utilizing computerized tomography.
      ]. In a study of 38 children and adults with deep neck infections, CT was shown to have a sensitivity of 88% for diagnosing an abscess [
      • Lazor J.B.
      • Cunningham M.J.
      • Eavey R.D.
      • Weber A.L.
      Comparison of computed tomography and surgical findings in deep neck infections.
      ]. A similar study of 16 CT scans of deep and lateral neck abscesses demonstrated a sensitivity of 91% [
      • Ungkanont K.
      • Yellon R.F.
      • Weissman J.L.
      • Casselbrant M.L.
      • Gonzalez-Valdepena H.
      • Bluestone C.D.
      ]. However, more than 90% of all pediatric neck masses will be inflammatory without an abscess. Moreover, self-limited viral infections mostly cause inflammation and lymph node hypertrophy, and children routinely experience idiopathic self-limiting episodes of lymph node enlargement, including lymph nodes of 2 to 3 cm in diameter. Therefore, considering radiation-related cancer risks related to the CT imaging of pediatric neck masses [
      • Brenner D.J.
      • Elliston C.D.
      Estimated radiation risks potentially associated with full-body CT screening.
      ], CT would be better if used as a second-line method for evaluating a neck mass. However, patients with some conditions that necessitate immediate surgical exploration and urgent otolaryngology consultation may be candidates for an initial CT evaluation.
      In clinical settings, CT is sometimes used as the first choice imaging modality for pediatric neck masses. At some institutions, a US technician may not be consistently available overnight or on weekends [
      • Collins B.
      • Stoner J.A.
      • Digoy G.P.
      Benefits of ultrasound vs. computed tomography in the diagnosis of pediatric lateral neck abscesses.
      ]. Consequently, less-experienced physicians in the emergency department might first order a CT scan for a small neck lesion that could result in omitting the evaluation by US, where the most of the pediatric neck mass can be differentially diagnosed without radiation. Herein, our aim was to evaluate the diagnostic effectiveness of and proper patient selection for neck CT as an initial evaluation method for pediatric neck masses in the emergency department.

      2. Materials and methods

      A retrospective chart review was performed of the medical records of pediatric patients who were younger than 15 years old who visited the emergency department of tertiary referral hospital between January 1, 2008, and December 31, 2012. Inclusion criteria were as follows: (1) patients presented with a neck mass or swelling; (2) initial imaging work-up included a neck CT; (3) no previous history of inflammatory cervical disease, congenital neck mass, neck operation, or malignancy such as lymphoma; and (4) no previous history of an immune-compromising disease or medication. Because the routine evaluation of pediatric neck mass is the US in the emergency department, initial neck CT was performed by several reasons such as unavailable sonographer, order by inexperienced physicians, and suspicion for emergent surgical conditions.
      Investigated parameters included the patient’s age, sex, symptom duration, initial impression, CT interpretation (location of neck mass, multiplicity, and neck mass characteristics), final diagnosis, and treatment. Final diagnosis is made mainly by pathologic and microbiological evaluation of excised or aspirated specimen, and some cases without any surgical specimen (ie, tonsillitis) reached to final diagnosis by response to medication. An indicators of predictive performance, including sensitivity, specificity, and positive predictive value (PPV), were calculated for CT imaging for each final diagnosis.
      We categorized the patients into 2 groups based on their requirement for urgent surgical exploration such as incision/drainage: group 1, patients who required urgent surgical exploration (ie, deep neck infection); and group 2, patients who required no emergent surgical exploration (ie, acute nonsuppurative cervical lymphadenopathy). Differences regarding patients’ symptoms and characteristic of neck mass between the 2 groups were evaluated.
      A statistical analysis was performed using the software package, SPSS for Windows, version 20.0 (SPSS Inc, Chicago, IL). A statistical difference between the 2 groups was evaluated using the independent t test for age and symptom onset and χ2 test for the other categorical parameters. To adjust for the correlated variables in univariate analysis, a binary logistic regression analysis was used to identify the factors independently associated with urgent surgical condition (dichotomous data). A P < .05 was considered statistically significant.

      3. Results

      A total of 105 patients were included in our study. The median age was 6.5 years (1 month to 12 years), and the male-to-female ratio was 2:1. The mean symptom duration was 4.1 (±2.5) days. Upon physical examination, the location of the neck mass was palpable unilaterally in 64 patients (60.9%), bilaterally in 26 patients (24.8%), and midline in 15 patients (14.3%). A single mass was palpable in 62 patients (59.0%), whereas multiple masses were palpable in 43 patients (41.0%). The most common clinical impression was acute cervical lymphadenopathy (30.5%), followed by a deep neck infection or an abscess (24.8%), a congenital mass such as a brachial cleft cyst (20.0%), a salivary gland infection (6.7%) or stone (4.8%), other benign mass (eg, lipoma) (3.8%), and malignancy (1.9%) (Table 1). Among 105 patients, 33 patients (31.4%) subsequently underwent ultrasonographic evaluation for further evaluation (9, 18, 4, and 2 patients for initial impression of cervical lymphadenopathy, congenital mass, other benign mass, and malignancy, respectively) (Fig. 2). The result of US in our study showed a significant correlation with CT scan (r = 0.316, P < .012).
      Table 1Demographic data, characteristics of neck mass on physical examination, and clinical impression
      Total patients105
      Median age (range)6.5 (1 mo to 12 y)
      Sex (M:F)2:1 (70:35)
      Mean symptom duration4.1 (±2.5) d
      Physical examination
      Location of mass
       Unilateral64 (60.9%)
       Bilateral26 (24.8%)
       Midline15 (14.3%)
      Multiplicity
       Single62 (59.0%)
       Multiple43 (41.0%)
      Clinical impression
      Cervical lymphadenopathy32 (30.5%)
      Deep neck infection, neck abscess26 (24.8%)
      Congenital mass21 (20.0%)
      Salivary gland infection7 (6.7%)
      Salivary gland stone5 (4.8%)
      Other benign mass4 (3.8%)
      Malignancy2 (1.9%)
      No description8 (7.6%)
      Final diagnosis
      Cervical lymphadenopathy49 (46.7%)
      Deep neck infection, neck abscess20 (19.0%)
      Congenital mass3 (2.9%)
      Salivary gland infection/stone15 (14.3%)
      Other infection12 (11.4%)
      Malignancy1 (1.0%)
      Others5 (4.8%)
      Abbreviation: M:F, male-to-female ratio.
      Figure thumbnail gr1
      Fig. 1Positive predictive value of CT for final diagnosis.
      Figure thumbnail gr2
      Fig. 2Diagnostic flow sheet of 20 patients who need urgent surgical exploration.
      Initial clinical impression and CT interpretation were well correlated for benign mass (100%) and congenital mass (81.0%) and moderately correlated for a deep neck infection or an abscess (77.8%) and acute cervical lymphadenopathy (71.4%). As for the clinical impression of a salivary gland infection or stone and malignancy, the initial impression and CT interpretation were poorly correlated (57.1% and 0%, respectively). In general, sensitivity, specificity, and PPV of CT scan for final diagnosis were 71.4%, 91.4%, and 96.2%, respectively. Positive predictive value showed 100% in case of deep neck infection and salivary gland stone, where the final diagnosis is made by operation; and salivary gland infection and tonsillitis, where the final diagnosis is made by CT imaging and response to medication (83.5% and 100% of sensitivity and specificity). For CT interpretation, cervical lymphadenopathy and a congenital mass had a PPV of 94.6% and 93.8%, respectively (Fig. 1).
      Table 2 shows the differences between groups 1 and 2. A fever of more than 38.0°C and severe tenderness demonstrated a significant difference between the 2 groups, whereas age, sex, symptom onset, swelling, mass location, laterality, and multiplicity showed no difference. Binary logistic regression analysis, which was used to adjust for fever (as a continuous variable) and tenderness (as a categorical variable), showed that factors associated with urgent surgical conditions were fever of more than 38.0°C (odds ratio, 6.609; 95% confidence interval, 1.046-41.867; P = .043).
      Table 2Difference between group 1 and group 2
      Group 1Group 2P
      Age (y)>6.7>6.2.301
      SexM>13>31.477
      F>8>16
      Symptom duration (d)4.0 (±2.1)>4.2 (±2.6)>0.685
      Swelling+>14>21.078
      >7>26
      Fever+>14>15.008
      >7>32
      Tenderness+>14>14.005
      >7>33
      Location of massLateral neck>12>31.457
      Parotid area>4>4
      Submandibular area>5>12
      Midline>0>2
      LateralityUnilateral>17>29.247
      Bilateral>4>16
      Multiplicity+>8>24.234
      >13>23
      Abbreviations: M, male; F, female.
      Group 1, patients who need surgical exploration (eg, deep neck infection); group 2, patients who need no surgical exploration (eg, acute nonsuppurative cervical lymphadenopathy).

      4. Discussion

      This study showed that neck CT can be used as an initial evaluation method for those patients whose physicians believe that their patients have a deep neck infection or an abscess accompanied by a high fever and severe tenderness during an initial examination. In terms of urgent surgical exploration, our institute routinely performs a neck CT before operating on a deep neck infection or an abscess because CT imaging of a lesion and the surrounding anatomy could help while performing appropriate and safe drainage, without injury to vital neck structures. In this clinical study, for pediatric patients who have a high probability of a deep neck infection requiring incision and drainage, using CT imaging without a US evaluation to determine a fast and accurate diagnosis may help in developing a treatment plan quickly, thereby decreasing the probability of worsening of disease.
      During routine evaluation of pediatric neck masses, US has been regarded as the first choice, although there have been reports regarding its limitation in evaluating midline neck masses [
      • Mallorie C.N.
      • Jones S.D.
      • Drage N.A.
      • Shepherd J.
      The reliability of high resolution ultrasound in the identification of pus collections in head and neck swellings.
      ,
      • Sidell D.R.
      • Shapiro N.L.
      Diagnostic accuracy of ultrasonography for midline neck masses in children.
      ]. Ultrasound has demonstrated great diagnostic performance in assessing thyroid masses, branchial cysts, and parotid lesions [
      • Hamoir M.
      • Bernheim N.
      • Vander Poorten V.
      • Chantrain G.
      • Van Laer C.
      • Hamans A.
      • et al.
      Initial assessment of a neck mass in children.
      ]. Moreover, for the head, the reliability of high resolution US for the distinction between a collection of purulent material and swelling without purulence was reported to be high, showing a sensitivity and specificity of 96% and 82%, respectively [
      • Mallorie C.N.
      • Jones S.D.
      • Drage N.A.
      • Shepherd J.
      The reliability of high resolution ultrasound in the identification of pus collections in head and neck swellings.
      ]. Despite this high diagnostic performance, drawback to the US is that US is examiner dependent. This makes the interpretation highly subjective and sometimes makes US unavailable if an examiner is not available. And for knowing surgical anatomy before the operation, we think that the data in neck CT are before the US due to lack of examiner dependency.
      In terms of diagnostic performance of deep neck infections, there have been some evaluations regarding US and CT in medical literature. Although a pediatric study showed a relatively low sensitivity for US, recent studies reported the comparable diagnostic performance of US with CT scan [
      • Kuhnemann S.
      • Keck T.
      • Riechelmann H.
      • Rettinger G.
      Rational diagnosis of pediatric pharyngeal abscess.
      ]. These were promising results, but the application of US to pediatric neck abscesses may be limited by the aforementioned disadvantages. Moreover, with CT, physicians were able to more accurately diagnose an abscess located in the deep neck and thus provide more reliable information to surgeons.
      In our study, the overall PPV for CT was 96.2%. As Fig. 1 shows, the PPV was 100% for a deep neck infection, a salivary gland infection, and tonsillitis. Although the correlation between the clinical impression and CT interpretation was not high in our study, a moderate correlation was observed regarding a deep neck infection and an abscess (77.8%). Furthermore, among patients who had a high fever and severe tenderness, CT revealed more cases that required urgent surgical exploration than those without high fever and tenderness. When a pediatric patient with a neck mass visits the emergency department and the clinical impression is a deep neck infection with a high fever and tenderness, there may be high probability of an urgent surgical condition that could be detected by CT. Subsequently, in those cases, CT may be the first choice for evaluating the pediatric neck mass.
      Computed tomography has a disadvantage in terms of radiation, and there are many concerns regarding the negative long-term effects of radiation from CT imaging. Computed tomography–related X-ray doses are large enough that statistically significant epidemiological evidence indicates a small increase in lifetime attributable risk of cancer incidence, ranging from 0.02% for 80-year-old men to nearly 1% for 20-year-old women [
      • Einstein A.J.
      • Henzlova M.J.
      • Rajagopalan S.
      Estimating risk of cancer associated with radiation exposure from 64-slice computed tomography coronary angiography.
      ]. On average, risks are 0.07% larger for children than adults. The cumulative radiation exposure for children younger than 15 years from having 2 to 3 head CTs may triple the risk of brain cancer [
      • Pearce M.S.
      • Salotti J.A.
      • Little M.P.
      • McHugh K.
      • Lee C.
      • Kim K.P.
      • et al.
      Radiation exposure from CT scans in childhood and subsequent risk of leukaemia and brain tumours: a retrospective cohort study.
      ]. Because of this limitation, CT must be carefully used in pediatric patients.
      There were several limitations in our study. First, this study was performed as a retrospective chart review. This study was not a well-organized prospective study, so there could be missing data or an incorrect medical record. Second, there might be a selection bias, where the some portion of our study group is included because of improper CT order.
      We are in absolute agreement that US should be the first recommended modality for evaluating pediatric neck masses. However, our results suggest that CT could be the first choice modality for both the evaluation and determination of a treatment plan for pediatric patients with a highly suspicious deep neck infection. A fast and accurate diagnosis followed by rapid referral to an head and neck surgeon could help more quickly ameliorate the patient’s status, thereby decreasing the incidence of actual malpractice cases caused by just waiting for a US.

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