This retrospective study evaluated the course of retropharyngeal and parapharyngeal abscesses in the function of the initial treatment. Globally, 19.8% of the patients required surgery. Of the 53 patients receiving the cefotaxime-rifampicin protocol as first-line treatment, 7.5% underwent surgery. In contrast, of the 53 patients who received an alternative protocol, 32.1% were operated on (p = 0.0025), corresponding to an HR of 0.21 (95% CI 0.047 to 0.93). The cefotaxime-rifampicin protocol introduced at first intention was a promising therapeutic strategy.
The choice of this dual-antibiotic therapy aims to cover staphylococcus with rifampicin, in addition to the other bacteria frequently found in the naso- and oropharynx, covered with cefotaxime [12, 13]. According to Fellner et al. [14], staphylococcus aureus and streptococci remain the main bacteria isolated in pediatric neck abscesses. In their study, of the staphylococcus aureus isolates, only 1 (8%) was methicillin-resistant; but 4 (31%) were clindamycin-resistant isolates with rare multiresistant. In Europe in 2017, 5.7% of staphylococcus aureus were resistant to rifampicin, which remains one of the standards of care, even though resistance to rifampicin may be a burden in the future [15]. Our results and those of the literature support a better efficacy of rifampicin than clindamycin. Only 7.5% of the patients who had the cefotaxime-rifampicin protocol as the first-line treatment required surgery, which is better than the results usually reported with clindamycin: the reported failure rates are of 18% for the combination of ceftriaxone and clindamycin [7], 25% when using Clindamycin alone [16] and 68.5% when using a combination of cefuroxime and metronidazole or clindamycin [17]. Concerning cefotaxime, its efficacy is the same as ceftriaxone in treating severe infections [18]. This dual-antibiotic therapy can be used in most children because of the low risk of allergy to cephalosporins and the low incidence of side effects for both antibiotics [19, 20]. The protocol duration is five days, leading to hospitalization of the same duration. For some teams, earlier return home at three days seems possible [8]. Ambulant follow-up of the patients in this critical period is also feasible. The advantage of a medical protocol is the reduction of the anesthetic risk and the absence of cervical scar and postoperative care. Conversely, choosing a medical strategy does not allow for systematic bacteriology, which is an obstacle to modifying the duration of antibiotic therapy and its spectrum in the future.
To avoid surgical drainage, bedside drainage by needle puncture under local anesthesia may be helpful if medical treatment fails; if pus is found [7], it allows bacteriologic analysis but with a higher risk of failure than drainage in the operating room. Therefore, surgical drainage in the operating room was preferred for our patients.
This study's median age of 4 years is close to that found in other studies and confirms that deep cervical abscesses are more common in young children. [1, 8, 13] The decreased risk of deep cervical abscesses in older children seems to be related to the regression of the lymph nodes in the retropharyngeal space around the age of 8 years [21]. The higher proportion of boys treated for this condition is consistently found in studies but is not explained [5, 7, 13].
CT scanning is the examination of choice for suspected deep cervical abscesses [22]. It allows the diagnosis to be established, the collection to be located, the measurements to be assessed, complications to be looked for, and the surgical procedure to be guided if necessary. It is also helpful to determine the presence or absence of pus during surgery based on the peripheral enhancement of the abscess [7]. A second CT scan is not routinely required in pediatric cases, where clinical surveillance is, in most cases, sufficient. However, a second CT scan is still necessary in the case of failure of medical treatment. In our series, 40% (6/15) of the indications for surgery were made following this second CT scan. Beyond the initial diagnosis, the CT scan can be used to correct uncertain diagnoses. In this series, three diagnoses of parapharyngeal abscesses were made following a second CT scan after the failure of orthopedic treatment for non-febrile torticollis. Three diagnoses of Kawasaki disease associated with parapharyngeal abscesses were made when fever persisted after six days of antibiotic therapy with the complete disappearance of the abscesses on the follow-up scan. Two CT scans were also needed to diagnose the recurrence of abscesses 48 hours after stopping the antibiotic treatment in the face of the reappearance of torticollis.
In our study, a threshold of 32 mm was associated with a higher risk of surgical drainage of the purulent collection. This measure is only indicative, and the link of causality cannot be established: the retrospective methodology does not allow it to be used as a criterion for surgical decisions. Indeed, a specific study should be conducted using three dimensions or volume measurements, with a reading by several radiologists, to assess a precise threshold leading to an indication of surgical management. As it was not the primary objective of this study, this specific analysis was not performed, and the measurements were only taken from the reports. Hence only 78/94 patients were included in the calculation. However, extended cervical collections in a child should encourage the clinician to be vigilant. According to some authors, a threshold of 20 mm should guide the surgeon toward surgery, even without clinical or radiological evidence of complications [7]. For others, an abscess > 25 mm should make the surgeon more vigilant about the need for surgery [5]. Given our results regarding the efficacy of the cefotaxime-rifampicin protocol, it seems reasonable to institute medical treatment for 48 hours before deciding on surgical drainage in the absence of clinical or radiological signs of complications, regardless of the size of the abscess.
This study does not illustrate an increased risk of failure of medical treatment when NSAIDs are used. The adverse role of NSAIDs is strongly suspected in developing serious infections [23–25]. NSAIDs may mask symptoms and allow the abscess to develop at a low level or aggravate the conditions. A longitudinal study, based on a cohort of more than 120 general practitioners in a sentinel network, showed that NSAIDs were prescribed in 22% of cases of pharyngitis, with an increased risk of peritonsillar abscess [24]. However, this link remains controversial and challenging to demonstrate. There are several pitfalls in studying the excess risk induced by NSAID use. There is a recruitment bias: patients treated in hospitals are more severe than those treated in the community, and self-medication with NSAIDs is also difficult to evaluate.
In contrast to NSAIDs, corticosteroids may improve the success rate of medical treatments and decrease the need for surgery. Goenka et al. found a lower drainage rate in the corticosteroid group (odds ratio: 0.28; 95% CI 0.22–0.36) on a massive cohort including 1677 patients without corticosteroids and 582 with corticosteroids on initial management [26]. Tansey et al. found a lower rate of surgical drainage (36%) in the dexamethasone group and compared with the non-dexamethasone group (53%, p = 0.043) on 153 patients mixing all cervical abscesses, including peritonsillar and lateral abscesses [27]. Villanueva-Fernandez et al. successfully treated 30 children, with 11 retropharyngeal and 19 parapharyngeal abscesses, using intravenous amoxicillin/clavulanic acid and corticosteroids, and also recommend reserving the surgical drainage for cases with a complication associated such as an airway compromise, lack of response to antibiotic therapy, and immunocompromised patients [28]. As these data on corticosteroids are recent, they may lead us to reconsider our management shortly. In our series, 26 patients received corticosteroids if they improved after 48 hours of antibiotic therapy. Still, the data in the charts were not precise enough to perform statistical analysis and draw conclusions.
This study has certain limitations. First, it is a retrospective study with biases related to data collection. However, the presence of computerized medical charts with the coding of the diagnosis strongly limits the loss of data. Second, to improve the accuracy of the collections' dimensions and validate their measurement, a repeatability and reproducibility study should be performed, which was not conducted here. Working on volumes rather than 2D dimensions may also improve the accuracy of the measurements on imaging. Third, validating the possible superiority of the Cefotaxime-rifampicin protocol over the others would require a prospective superiority study with a control group, which is a line of future work. Fourth, this study's results are valid for our bacterial ecology. Other combinations of antibiotics may be more relevant elsewhere, depending on the local bacterial ecology.