Original Paper Pediatr Neurosurg 2014–15;50:187–195 DOI: 10.1159/000431179
Received: August 13, 2014 Accepted after revision: May 6, 2015 Published online: June 23, 2015
Intracranial Injuries from Dog Bites in Children Talora Steen a, c Karen Ravin b Shelly Timmons c Amir Kershenovich c, d a
University of Pittsburgh School of Medicine, Pittsburgh, Pa., b Department of Pediatric Infectious Disease, Geisinger Health System and Janet Weis Children’s Hospital and c Department of Neurosurgery, Geisinger Health System, Danville, Pa., and d Temple School of Medicine, Philadelphia, Pa., USA
Key Words Intracranial injuries · Dog bites · Broad spectrum antibiotics · Irrigation and debridement · Hematoma
Abstract Background/Aims: Infants are especially at risk for intracranial injuries from dog bites due to their small stature and thin skull. Only 21 case reports have been published in the literature. We aim to add knowledge and treatment recommendations based on a more substantial sample. Methods: Ten pediatric patients with a penetrating skull injury as a result of a dog bite, treated at our institution between 1992 and 2010, were identified and analyzed descriptively. A literature review of the 21 case reports was also conducted. Results and Conclusion: Early diagnosis and treatment can prevent complications from hemorrhage or infections. Based on our results, we recommend obtaining a head CT for all victims sustaining injuries to the head, early use of broad spectrum antibiotics, debridement and irrigation of tissue, and followup to identify late infectious complications. © 2015 S. Karger AG, Basel
Methods
Dog bites are not an uncommon event, accounting for 12.9 new injuries for every 10,000 people in the USA each year. This statistic rises to 60.7 injuries per 10,000 indi© 2015 S. Karger AG, Basel 1016–2291/15/0504–0187$39.50/0
The trauma database at Geisinger Health System in Danville (Pa., USA) was used to select the clinical cases for this retrospective study. The written and electronic records for all pediatric dog bite victims admitted to the hospital between 1992 and 2010 were analyzed for
Amir Kershenovich, MD Geisinger Health System 100 North Academy Avenue, MD 14-05 Danville, PA 17822 (USA) E-Mail akershenovich1 @ geisinger.edu
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Introduction
E-Mail [email protected] www.karger.com/pne
viduals when considering only pediatric cases [1]. Furthermore, children under the age of 6 years are more likely to be bitten on the head, face or neck [2]. Individuals younger than 3 years old are particularly vulnerable to intracranial damage due to their smaller size, lower stature, greater head-to-body surface ratio, thin skull bones and poor defense abilities [3]. Also, as a dog bite can create pressures as great as 28.12 kg/cm [2, 4], a child’s skull can be easily penetrated. After an intracranial dog bite, direct inoculation of the brain can occur and may cause infections and abscesses. The most common organisms causing infections from dog bites include: Pasteurella species, Staphylococcus aureus, Capnocytophaga canimorsus and alpha-hemolytic streptococcus [3]. Additionally, anaerobic bacteria pose a risk, comprising as much as 30–40% of canine oral flora [5]. Consequently, antimicrobial prophylaxis is usually recommended. To the best of our knowledge, there have been only 21 isolated cases of intracranial injuries due to dog bites in children reported in the modern literature [2, 3, 5–18]. Here, we report our experience at Geisinger Health System since 1992 and also provide a literature review.
Results
Demographics In our series, the mean age at injury was 34.5 months and ranged from 10 days to 9 years. There were 6 males and 4 females (ratio 1.5:1). Four children were attacked by their immediate family’s pet dog, and the other 5 were attacked by dogs owned by a relative; the owner of 1 dog was not reported. In 9 of the 10 cases, the breed of the dog involved in the attack was reported, and all of these were characterized as being of middle to large in size (table 1). Thirty percent of the patients were directly admitted to Geisinger Health System, while the remaining 70% were transferred from other institutions. In the literature review, the mean age at injury was 14.2 months (median of 13 months), with a range of 2 weeks to 3 years. There were 6 males and 15 females (male to female ratio 0.4:1; table 2). The breed of dog was reported in 18 cases, and all were characterized as being middle to large in size. Presentation Within our series, only 2 patients, both under 18 months old, had an open fontanelle that was not noted to be bulging or tense. Nine patients had documentation for the presenting Glasgow coma scale, and all had a score of 15 at the time of admission. All patients had scalp lacerations. Most had bilateral or both anterior and posterior lacerations; 2 patients had lacerations on only one area of the head/face. Four patients sustained the main scalp laceration on the left side, 3 on the right and 3 bilaterally. Four patients had their main scalp laceration on the frontal area, 3 on the posterior temporal area, 2 on the occipital area, and 1 suffered global avulsion of the scalp. Sixty percent of patients had associated facial lacerations, while only 1 suffered from a neck injury. According to our literature review, 13 patients had two or more fractures. Eighteen of the 21 patients presented with a Glasgow coma scale of 15, and only 3 had an abnormal state of consciousness at presentation. Of the 3, 1 was somnolent, 1 was lethargic and 1 was unresponsive. The patient with lethargy was the only 1 of the 3 that was initially misdiagnosed and presented 2 days after the original injury. 188
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Imaging In our series, we were able to review the CT scans for 8 of the 10 patients, with only a radiologist’s interpretation was available for the remaining 2. All patients had head CT evidence of a penetrating skull injury. Five patients sustained penetrating skull lesions on the left side with 3 on the right and 2 in both regions; 50% of the children had multiple skull fractures. Ninety percent of patients had pneumocephalus, which in all cases were in the area of the fracture (fig. 1, 2). The patient without evidence of pneumocephalus was 1 of the 2 for whom we only had a radiology report available. In relation to the scalp injuries, 1 patient had a fracture in an area different from the scalp laceration. Three patients had extra-axial hematomas, and 2 of these were the youngest in the series (table 1). In the literature, 14 patients had a CT scan, but one of these CT scans was taken only after a dural tear became evident in surgery. Five had only an XR performed as the main diagnostic imaging tool. One had an MRI without having a CT scan. One case report did not have a comment on imaging. Five cases were reported as pneumocephalus. Management The average length of the hospital stay in our series was 2.9 days with a range of 1–9 days. Forty percent of the patients were admitted to the pediatric intensive care unit (PICU), and 1 patient had evidence of a cerebrospinal fluid (CSF) leak. In the literature, the mean length of stay was 22.1 days, and the median stay was 21 days. Surgery At our institution, 5 of 10 patients underwent neurosurgical interventions (i.e. wound debridement, removal of comminuted fracture bones, and primary repair of a dura mater laceration), one of which was performed by a pediatric general surgeon. Debridement and irrigation were the most commonly performed procedures; none of the extra-axial hemorrhages required surgical evacuation. Dural repair was performed in only 1 case; hemostasis of a mastoid emissary bleeding vein was necessitated in another case. None of the patients required a return to the operating room. All patients sustained additional lacerations of the head, face or neck other than the intracranial lesion as follows: 2 patients in the neck, 6 in the face, 5 in the ears, and 5 in the eyes/orbits/eyelids. Eight patients required nonneurosurgical procedures for these lacerations, which were performed by a plastic surgeon in 3 cases, an ophthalmologist in 5 cases, Steen/Ravin/Timmons/Kershenovich
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potential inclusion in this study, which consisted of patients aged 0–18 years who sustained a head and/or face injury with evidence of a penetrating skull injury on head/brain CT scan images. A total of 10 patients were identified and included in the study. The Geisinger Health System Institutional Review Board approved protocol 20110107 (federal-wide assurance 00000063) for this study.
Table 1. Institutional clinical data and management Gender/age Dog Dog breed at attack, owner months
Location of skull fracture
Patient 1 F/11.5
Parent Mixed
Patient 2 M/29
Uncle
Patient 3 M/19.9
Parent Rottweiler
Patient 4 M/3
Left occipital Parent Alaskan malamute/ Australian shepherd mix
Patient 5 F/116.7
No Bull report mastiff
Patient 6 M/33.2
Pneumocephalus
Extra-axial hemorrhage
Initial antibiotic (added antibiotic)
Left temporal, Left frontal, left nasal bone, left orbit inferolateral margin of left orbit
Left frontal
Augmentin
Right temporal
Right temporal
None
Ancef
Bilateral parietal
Bilateral parietal
None
Left occipital
Switched antibiotic
PICC Total days Surgical line of antibiotic management treatment
No
10
Repair of dural tear with galea. Washout
No
11
Comminuted bones removed. Washout
Clindamycin
No
9
None
Left occipital
Unasyn
No
1
None
Right parietal, Left occipital left occipital, right temporal
None
Unasyn
Vancomycin, Meropenem
Yes
18
Hemostasis of mastoidal emissary vein. Washout
Friend Saint bernard
Parasagittal left frontal
Left orbit
None
Unasyn and nafcillin
Meropenem
Yes
16
Washout
Patient 7 F/29.2
Aunt
Right parietal
Right parietal
None
Unasyn
Meropenem, Augmentin
Yes
18
Washout in the ED
Patient 8 F/35.9
Parent Pit bull
Left temporal, Left temporal and left frontal left petrous bone, left occipital
Left temporal Ampicillin Unasyn, (gentamicin) Meropenem (Flagyl)
Yes
10
Primary dural repair; comminuted bones removed. Washout
Patient 9 M/48.6
Uncle
German shepherd
Base of skull, right superior orbit
Right superior orbit
None
Unasyn
Augmentin
Yes
14
None
Patient 10 M/21.8
Aunt
Doberman Left frontal pinscher
None
None
Ceftriaxone
Cefazolin
No
1
None
Pit bull
Saint bernard
Unasyn, Augmentin
an otolaryngologist in 5 cases, an oral and maxillofacial surgeon in 1 case, and a pediatric surgeon in 1 case. Two patients did not require any procedures as their lacerations were posterior to the ear, and neurosurgery was the only consulted service for these cases. Overall, the neurosurgery service was consulted in 9 of the 10 cases. On follow-up after hospital discharge, none of the children had developed brain abscesses, extra-axial empyemas or meningitis.
All 21 patients reported in the literature required neurosurgical intervention, with 9 of them receiving intervention more than 24 h after their injury. Seven of these were inadequately evaluated initially, and the diagnosis of an intracranial injury was missed. Nine of the 21 patients were initially managed with only debridement, irrigation and/or repair of cutaneous lacerations, with 8 patients requiring a second intervention. Of these patients, 6 had a missed initial diagnosis and 5 required elevation of depressed fractures.
Pediatric Intracranial Dog Bites
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PICC = Peripherally inserted central catheter; ED = emergency department.
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Steen/Ravin/Timmons/Kershenovich
8
15
9 12 2 8
24
0.5
0.5
Wilberger [17], 1981
Cowie [7], 1983
Wilberger [18], 1983
Sutton [14], 1984
Kenevan [8], 1985
Steinbok [13], 1985
24 36
24
20
Pinto [12], 2008
Santana-Montero [2], 2009
Burns [6], 2011
F
F
M F
F
F
F
M
M
F F M F
F
F
F M
F
F
F
No
No
No No
No
Yes
No
No
No
No No No Yes
No
Yes
Yes No
No
No
No
Gender Intracranial hematoma
N/A = Not available; d/c = discharge.
18
Iannelli [3], 2005
0.5
8 4
Pinckney [11], 1980
19
Klein [9], 1978
13
18
O’Riordan [10], 1976
Watson [16], 1980
Age, months
First author and year
Yes
N/A
Yes Yes
Yes
Yes
Yes
Yes
Yes
Yes No No Yes
Yes
Yes
N/A N/A
N/A
N/A
Yes
Dural tear
Table 2. Literature review of intracranial dog bite injuries
No
Abscess (late)
No No
No
Meningitis, followed by abscess (late) No
Meningitis (late)
Abscess (late)
Yes No No No
Yes
No
No No
Meningitis
Abscess (late)
No
Infections
N/A
No
N/A N/A
N/A
N/A
Yes (CSF)
N/A
No; taken 4 days after event
Yes (wound) Yes N/A N/A
Yes (wound)
N/A
N/A N/A
Yes (CSF)
No
N/A
Initial cultures
N/A
N/A
N/A N/A
N/A
N/A
Pasteurella (meningitis)
Meningitis prophylaxis, unspecified (N/A)
Ceftriaxone (7 days)
Oxacillin, ceftriaxone, metronidazole (14 days) Oxacillin, ceftriaxone, metronidazole (14 days)
Cephalosporin and vancomycin (15 days)
Penicillin and cloxacillin (1 week)
Chloramphenicol and ampicillin (9 and 14 days postoperatively, respectively)
Prophylactic antibiotics (unspecified); followed by penicillin and kanamycin (both N/A)
Cephalexin (4 days); followed by chloramphenicol and oxacillin with discovery of abscess (N/A); followed by penicillin (3 weeks)
Peptococcus species
No growth (cultured from CSF on day 5 due to fever). Gram stain was positive for bacteria
Chloramphenicol and oxacillin (10 days) Oxacillin (10 days) Oxacillin (10 days) Chloramphenicol and oxacillin (10 days)
Penicillin and flucloxacillin (N/A)
Chloramphenicol and oxacillin (7 days)
N/A N/A
Penicillin G (6 weeks)
None; unspecified antibiotics later given for abscess (N/A)
Ampicillin upon d/c (1 day); followed by penicillin 1 day after the event (N/A)
Initial antibiotics (length of treatment)
Klebsiella and Proteus None N/A N/A
S. aureus, E. cloacae
N/A
N/A N/A
Pasteurella
Pasteurella cultured from abscess 3 weeks after event
N/A
Cultures at infection
Fig. 1. Head CT, bone window of patients 1 (coronal view), 2, 3 and 5 (axial view), showing the fractures and pneumocephalus. The star symbol shows the area of interest.
Fig. 2. Head CT, bone window of patients 6, 7 (axial view), 8 (sagittal view) and 9 (coronal view) showing the
fractures and pneumocephalus. The star symbol shows the area of interest.
Antibiotics In our series, all patients were treated with antibiotics and 50% were discharged home with a peripherally inserted central catheter line for continued parenteral antibiotic therapy. Forty percent of patients were treated at least once with amoxicillin/clavulanic acid. Seventy percent of patients were initially treated with either ampicillin or ampicillin/sulbactam. Of these, 3 were switched to meropenem by the infectious disease consultant. One patient was treated with clindamycin due to a known amoxicillin allergy. Six patients were treated with two to three antibiotics simultaneously. Only 40% of patients were maintained on the same initial antibiotic type, whereas 40% had their therapy changed once, and 20% were changed three times. The average number of antibiotics Pediatric Intracranial Dog Bites
used was 2.4 with a range of 1–5. The mean duration of antibiotic therapy was 10.8 days with a range of 1–18 days (table 1). Only 1 patient had a culture taken from the wound that showed no bacterial growth. In the literature review, as summarized in table 2, 18 of 21 patients were reported to receive antibiotic treatment during the course of their hospital admission; three case reports did not document initial antibiotic therapy. The median length of the initial antibiotic treatment was 10 days. Cultures were reported to have been taken in only 9 cases, with 5 at the time of admission (only 4 grew microorganisms). Of the 4 patients presenting with infections, cultures grew Pasteurella (treated with penicillin G in 1 patient and chloramphenicol and ampicillin in another) Klebsiella and Proteus (treated with chloramphenicol and oxacillin), and S. aureus and Enterobacter cloacae (treated with penicillin and flucloxacillin). An inadequate initial evaluation in 4 patients resulted in 3 of them developing brain abscesses; cultures grew Pasteurella (treated with unspecified antibiotics) and Peptococcus species (treated with chloramphenicol and oxacillin), and 1 case report did not contain documentation of the microorganism or the treatment. The patient with meningitis developed fever on the 5th day of his hosPediatr Neurosurg 2014–15;50:187–195 DOI: 10.1159/000431179
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Fourteen patients were reported to have dural lacerations or CSF leaks. In addition, 4 more ultimately had meningitis (n = 1) or brain abscesses (n = 3; 2 were drained surgically), which means that in retrospect they did have a dural transgression. Ten patients required dural repairs of which only six were performed within 24 h. Four patients required evacuation of intracranial hematomas, which were all performed within 24 h of injury.
Laboratory Tests In our series, 9 patients had hemoglobin documented at the time of admission and 4 showed mild anemia. Eight patients had a documented white cell count; 5 patients had leukocytosis, of which 2 had a differential cell analysis showing a mildly elevated neutrophil count. Seven patients had a basic metabolic panel; only 2 of these patients showed abnormal values, and both had hyperkalemia and hyperglycemia. All had normal plasma sodium, creatinine, calcium and BUN (blood urea nitrogen). Immunizations Two of the patients treated by us received a tetanus vaccine. None were documented to have received a rabies vaccine. Follow-Up and Outcomes In our series, 6 of the 10 patients were seen at least once in the neurosurgery outpatient clinic after discharge, and 9 had at least one documented outpatient clinic visit with a nonneurosurgical provider within the system with enough information to be able to assess the gross neurological condition. The mean follow-up after hospital discharge was 30 months (median 26 months, range 11–36). The average time from hospital discharge to the first follow-up visit was 24 days (range 3–50). None of the followed patients had complications. In the literature review, the mean follow-up for 11 patients with documented outpatient clinic visits after discharge was 6 months (range 2–27). The other 5 patients had some follow-up information as well. During the follow-up appointments 3 patients were diagnosed with late infections – 2 had hemiparesis and 1 had persistent peripheral nerve palsies. Two patients had seizures, including 1 during admission who also had disseminated intravascular coagulation, a cardiac arrest, and died.
Discussion
We found only 21 pediatric cases of intracranial dog bite injuries reported in the literature. Seventeen were single case reports with three reporting 2 cases [11–13, 15], and one reporting 4 cases [18]. In contrast to these previously reported cases, our patients were slightly older 192
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(median of 29 months compared to 13 months). Although infants are more susceptible to intracranial dog bite injuries because of their thin skulls, it is likely that they are not left unattended with dogs as often as older children. Furthermore, the height of toddler-aged children most likely places them at the level of a medium- to large-sized dog’s mouth, which may explain why they are also at risk. All dog breeds in our study and most in the literature review cohort were of medium to large size. Our medical center has been continuously accredited as an adult level 1 regional trauma center since 1984, and in 1996 it acquired additional qualifications in pediatric trauma. In 2008, the Children’s Hospital was accredited as a level 2 pediatric trauma center. Overall, Geisinger Medical Center and Janet Weis Children’s Hospital have acted as the main trauma center in the region for over 20 years, serving an estimated population of 2.5 million habitants. With this in mind, for over 19 years, we have treated 10 patients with documented intracranial injuries from dog bites for a rough prevalence of 1 case every 2 years. So, although uncommon, this is a pathology that all pediatric neurosurgeons will encounter in their careers several times. Three patients in our sample sustained extra-axial hemorrhages. We believe that the commonality of these injuries was the relative thinness of the skull bone, either due to young age or the anatomic location, as two occurred in infants (frontal and occipital bones) and the other in the temporal bone of a toddler. Two of these patients sustained a dural laceration. Regardless of whether the victim was an infant or a toddler, it is our opinion that there should be a low threshold for wound exploration when the injury involves the temporal bone, as it will be more prone to be associated with a dural laceration with or without an extra-axial hemorrhage. We also recommend exploration and debridement for comminuted injuries, because they are more likely to be associated with dural lacerations [19]. In the reviewed literature, a high frequency of major infectious complications was noted with 8 out of 21 (38%) patients experiencing infections and 14 out of 21 (66%) patients having dural lacerations (table 2). Five of the 8 patients who experienced infectious complications had a documented dural laceration. We suspected that 3 additional patients had a dural laceration as 2 developed a brain abscess and 1 had meningitis, but patients were not reported to have a dural laceration at the initial injury. In contrast, only 2 of 10 (20%) patients in our series experienced dural lacerations. They both underwent early CSF leak repair and neither had an infection. When our series was included in the literature review the rate of inSteen/Ravin/Timmons/Kershenovich
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pital admission and cultures were taken to confirm the diagnosis of meningitis but without bacterial growth. The patient was treated with high doses of i.v. penicillin and i.v. kanamycin.
infectious disease service may help avoid multiple changes in the antibiotic regimen. The median duration of antibiotic therapy in our series was 10.5 days with a range of 1–18 days. We recommend completing a 10- to 14-day regimen depending on the clinical course. We also recommend that a tetanus vaccine be given as per the most current immunization schedule. Four of the cases published in the reviewed literature reported intracranial hematomas, all of which were surgically evacuated (table 2). Thirty percent of our patients had extra-axial hemorrhages, none of which required surgical intervention. When including the literature cases, the frequency of having an intracranial extra-axial hemorrhage following an intracranial dog bite injury is 22.6% (table 2). Though not published, anecdotal catastrophic and even fatal cases of intracranial injuries from dog bites exist and, thus, like other types of injuries, these can range from mild to severe; our series may not reflect this entire range. If there is a suspicion of a major vascular injury, such as a large hematoma, or if there is an increased risk of one that is due to the location of penetration, then surgical management should be in accordance with usual neurosurgical practice. We are aware of the discrepancy between our results and the literature review. We do not pretend to state that intracranial dog bite injuries are in general mild, but we also bring another perspective to the published literature in that many of these injuries, when adequately identified and treated promptly, will result in positive outcomes without complications as long as the injury is not in a bad location such as a sinus or is deep enough to lacerate important feeding arteries or draining veins. We think that it is essential to suspect a possible penetrating injury to the skull when a scalp laceration is present and, therefore, recommend an aggressive imaging investigation with a head CT. Missing the diagnosis can prevent an early washout and adequate antibiotic treatment which can prevent later infections. Scalp lacerations generally tend to have significant bleeding. This can be dangerous in young children who have low blood volumes because it places them at higher risk for anemia from these injuries. Young children with large or extensive lacerations and significant blood loss merit observation in the PICU setting. In our series, 40% of the children spent their first night of hospitalization in the PICU. Of these, 3 had extra-axial hemorrhages. The remaining patient had a parasagittal fracture and required debridement. Interestingly, none of our patients or the 21 in the literature review experienced hemorrhages as a result of injury to the superior sagittal sinus or the transverse sinuses.
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fection and dural laceration following an intracranial dog bite dropped to 25.8 and 51.6%, respectively. Considering the lower rate of infections and dural lacerations in our series as compared to the literature, we believe that there may be a selection bias in the reporting of intracranial dog bite injuries in children. It is likely that most patients have an uneventful course similar to our sample and their cases have not been published. Additionally, the age difference between our cases and those previously reported in the literature could also explain the disparity of infectious complications between these two groups. Our relatively older sample of patients would be expected to have a more fully developed immune system, which may have protected them from infectious complications as compared to younger infants. Considering the high risk of infection reported in the literature, it is not surprising that our physicians have taken great care to prevent infections. Sixty percent of our patients underwent wound washout prior to wound closure. All 10 of our patients were prescribed empiric broad spectrum antibiotics. This management is consistent with the literature (table 2). Although initiating antibiotics in the emergency department may also contribute to better outcomes and fewer infectious complications, it would appear that a randomized controlled study is needed to assess whether prophylactic antibiotics are needed for these injuries. Unfortunately, such a study is unrealistic not only because of the small number of cases, but also because of reports describing life-threatening conditions such as brain abscesses and meningitis [2, 8, 9, 11, 13, 14]. Despite the risk of infection, current recommendations for antibiotic prophylaxis remain controversial. Smith et al. [20] suggested that there is little evidence of benefit for the use of antibiotics for dog bite injuries. However, other authors have recommended empiric antibiotics for any dog bite injury with bone involvement, especially if there is CSF inoculation [4, 21–23]. When infection does occur, P. multocida is isolated in culture in more than 50% of cases, followed by Staphylococcus (25%) and Streptococcus (15%) [4]. Only 40% of our patients were maintained on the same initial antibiotic throughout their hospital stay. Antibiotics were changed multiple times prior to consultation with the pediatric infectious disease specialist. There is a lack of consensus in the literature on the optimal regimen of antibiotic coverage. Based on our experience, review of the literature and knowledge of the common canine oral microorganisms, we recommend that patients be treated with a broad-spectrum antibiotic with effective CNS penetration, such as meropenem. Early consultation with the
Since pneumocephalus was a consistent finding on imaging (90%) in our study (table 1), we recommend that all children with a dog bite wound to the head should be evaluated with a brain CT. None of our patients had seizures, and only 2 patients in the literature review experienced seizures. We suggest that evidence-based guidelines regarding seizure prophylaxis for patients with extra-axial hematomas, parenchymal hematomas and depressed skull fractures be followed [24, 25]. We have found that 8 patients in the literature review were initially erroneously evaluated; fractures were missed on imaging in 3 patients, and 5 patients were discharged from the hospital on the same day after treatment for superficial wounds only. They were readmitted from 1 day to 2 months after the inciting event. Six of the 8 patients had complications – 4 had infections and 2 had a CSF leak. Follow-up for all patients in our series and those reviewed from the literature was heterogeneous and lacked an organized structure. Our study’s results indicate that there are grossly two types of patients: those with adequate diagnosis and aggressive management, and those with a missed or delayed diagnosis. The former group tends to have good outcomes and few complications, whereas the later was associated with high complication rates. In the face of these observations, we recommend a structured follow-up after hospital discharge, consisting of a wound check and clinical assessment at the neurosurgical clinic, as well as a visit with the infectious disease specialist at 1 and 3 weeks after discharge, followed by neurosurgery follow-up at 2 and 4 months after discharge. Follow-up brain imaging is at the discretion of the neurosurgeon, individualized upon the patient’s presentation and risk of developing a brain abscess. With regards to preventing injuries to the cranium from dog bites, we believe that educating families with
dogs to avoid leaving infants and young children alone or in close proximity to a dog is reasonable, especially those with medium- to large-sized dogs. Our study is limited by virtue of the small sample and being a retrospective case review in a single institution. However, the authors believe that our results and observations will be helpful to those providers who are seeking advice for the management of intracranial dog bite injuries.
Conclusions
Intracranial injuries from dog bites in children should be thoroughly investigated and aggressively managed by surgical debridement and irrigation in cases where a scalp laceration or dural tear is present. A head CT scan without contrast is recommended for all children sustaining dog bites to the head. Surgical exploration should be undertaken when there is evidence of comminuted fractures on imaging studies. A broad-spectrum antibiotic should be initiated early (within 24 h of the injury) and utilized for a relatively short period of time of about 10–14 days. Follow-up in the neurosurgery clinic can help to identify early subacute or chronic infectious complications. Acknowledgements We express a special thank you to Marian Repella Kozak for her invaluable editorial assistance.
Disclosure Statement The authors have no conflicts of interest to declare.
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1 Weiss HB, Friedman DI, Coben JH: Incidence of dog bite injuries treated in emergency departments. JAMA 1998;279:51–53. 2 Santana-Montero BL, Ahumada-Mendoza H, Vaca-Ruíz MA, Castro-Sierra E, SánchezHerrera F, Fernández-Portilla E, Sosa-Quintero RM, González-Carranza V, GordilloDomínguez LF, Garza-Morales S, ChicoPonce de Leon F: Cerebellar abscesses caused by dog bite: a case report. Childs Nerv Syst 2009;25:1137–1141. 3 Iannelli A, Lupi G: Penetrating brain injuries from a dog bite in an infant. Pediatr Neurosurg 2005;41:41–45.
Pediatric Intracranial Dog Bites
18 Wilberger JE Jr, Pang D: Craniocerebral injuries from dog bites. JAMA 1983; 249: 2685– 2688. 19 Asano T, Ohno K, Takada Y, Suzuki R, Hirakawa K, Monma S: Fractures of the floor of the anterior cranial fossa. J Trauma 1995; 39: 702–706. 20 Smith MR, Walker A, Brenchley J: Barking up the wrong tree? A survey of dog bite wound management. Emerg Med J 2003; 20: 253–255. 21 Davis SJM, Valla FR: Evidence for domestication of the dog 12,000 years ago in the Natufian of Israel. Nature 1978;276:608–610.
22 Mitchell RB, Nanez G, Wagner JD, Kelly J: Dog bites of the scalp, face, and neck in children. Laryngoscope 2003;113:492–495. 23 Peters V, Sottiaux M, Appelboom J, Kahn A: Posttraumatic stress disorder after dog bites in children. J Pediatr 2004;144:121–122. 24 Chiaretti A, De Benedictis R, Polidori G, Piastra M, Iannelli A, Di Rocco C: Early posttraumatic seizures in children with head injury. Childs Nerv Syst 2000;16:862–866. 25 Ciurea AV, Gorgan MR, Tascu A, Sandu AM, Rizea RE: Traumatic brain injury in infants and toddlers, 0–3 years old. J Med Life 2011; 4:234–243.
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13 Steinbok P, Flodmark O, Scheifele DW: Animal bites causing central nervous system injury in children: a report of three cases. Pediatr Neurosci 1985;12:96–100. 14 Sutton LN, Alpert G: Brain abscess following cranial dog bite. Clin Pediatr 1984;23:580. 15 Tu AH, Girotto JA, Singh N, Dufresne CR, Robertson BC, Seyfer AE, Manson PN, Iliff N: Facial fractures from dog bite injuries. Plast Reconstr Surg 2002;109:1259–1265. 16 Watson DW: Severe head injury from dog bites. Ann Emerg Med 1980;9:28–30. 17 Wilberger JE Jr, Pang D: Craniocerebral injuries from dog bite in an infant. Neurosurgery 1981;9:426–428.
Received: August 13, 2014 Accepted after revision: May 6, 2015 Published online: June 23, 2015
Intracranial Injuries from Dog Bites in Children Talora Steen a, c Karen Ravin b Shelly Timmons c Amir Kershenovich c, d a
University of Pittsburgh School of Medicine, Pittsburgh, Pa., b Department of Pediatric Infectious Disease, Geisinger Health System and Janet Weis Children’s Hospital and c Department of Neurosurgery, Geisinger Health System, Danville, Pa., and d Temple School of Medicine, Philadelphia, Pa., USA
Key Words Intracranial injuries · Dog bites · Broad spectrum antibiotics · Irrigation and debridement · Hematoma
Abstract Background/Aims: Infants are especially at risk for intracranial injuries from dog bites due to their small stature and thin skull. Only 21 case reports have been published in the literature. We aim to add knowledge and treatment recommendations based on a more substantial sample. Methods: Ten pediatric patients with a penetrating skull injury as a result of a dog bite, treated at our institution between 1992 and 2010, were identified and analyzed descriptively. A literature review of the 21 case reports was also conducted. Results and Conclusion: Early diagnosis and treatment can prevent complications from hemorrhage or infections. Based on our results, we recommend obtaining a head CT for all victims sustaining injuries to the head, early use of broad spectrum antibiotics, debridement and irrigation of tissue, and followup to identify late infectious complications. © 2015 S. Karger AG, Basel
Methods
Dog bites are not an uncommon event, accounting for 12.9 new injuries for every 10,000 people in the USA each year. This statistic rises to 60.7 injuries per 10,000 indi© 2015 S. Karger AG, Basel 1016–2291/15/0504–0187$39.50/0
The trauma database at Geisinger Health System in Danville (Pa., USA) was used to select the clinical cases for this retrospective study. The written and electronic records for all pediatric dog bite victims admitted to the hospital between 1992 and 2010 were analyzed for
Amir Kershenovich, MD Geisinger Health System 100 North Academy Avenue, MD 14-05 Danville, PA 17822 (USA) E-Mail akershenovich1 @ geisinger.edu
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Introduction
E-Mail [email protected] www.karger.com/pne
viduals when considering only pediatric cases [1]. Furthermore, children under the age of 6 years are more likely to be bitten on the head, face or neck [2]. Individuals younger than 3 years old are particularly vulnerable to intracranial damage due to their smaller size, lower stature, greater head-to-body surface ratio, thin skull bones and poor defense abilities [3]. Also, as a dog bite can create pressures as great as 28.12 kg/cm [2, 4], a child’s skull can be easily penetrated. After an intracranial dog bite, direct inoculation of the brain can occur and may cause infections and abscesses. The most common organisms causing infections from dog bites include: Pasteurella species, Staphylococcus aureus, Capnocytophaga canimorsus and alpha-hemolytic streptococcus [3]. Additionally, anaerobic bacteria pose a risk, comprising as much as 30–40% of canine oral flora [5]. Consequently, antimicrobial prophylaxis is usually recommended. To the best of our knowledge, there have been only 21 isolated cases of intracranial injuries due to dog bites in children reported in the modern literature [2, 3, 5–18]. Here, we report our experience at Geisinger Health System since 1992 and also provide a literature review.
Results
Demographics In our series, the mean age at injury was 34.5 months and ranged from 10 days to 9 years. There were 6 males and 4 females (ratio 1.5:1). Four children were attacked by their immediate family’s pet dog, and the other 5 were attacked by dogs owned by a relative; the owner of 1 dog was not reported. In 9 of the 10 cases, the breed of the dog involved in the attack was reported, and all of these were characterized as being of middle to large in size (table 1). Thirty percent of the patients were directly admitted to Geisinger Health System, while the remaining 70% were transferred from other institutions. In the literature review, the mean age at injury was 14.2 months (median of 13 months), with a range of 2 weeks to 3 years. There were 6 males and 15 females (male to female ratio 0.4:1; table 2). The breed of dog was reported in 18 cases, and all were characterized as being middle to large in size. Presentation Within our series, only 2 patients, both under 18 months old, had an open fontanelle that was not noted to be bulging or tense. Nine patients had documentation for the presenting Glasgow coma scale, and all had a score of 15 at the time of admission. All patients had scalp lacerations. Most had bilateral or both anterior and posterior lacerations; 2 patients had lacerations on only one area of the head/face. Four patients sustained the main scalp laceration on the left side, 3 on the right and 3 bilaterally. Four patients had their main scalp laceration on the frontal area, 3 on the posterior temporal area, 2 on the occipital area, and 1 suffered global avulsion of the scalp. Sixty percent of patients had associated facial lacerations, while only 1 suffered from a neck injury. According to our literature review, 13 patients had two or more fractures. Eighteen of the 21 patients presented with a Glasgow coma scale of 15, and only 3 had an abnormal state of consciousness at presentation. Of the 3, 1 was somnolent, 1 was lethargic and 1 was unresponsive. The patient with lethargy was the only 1 of the 3 that was initially misdiagnosed and presented 2 days after the original injury. 188
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Imaging In our series, we were able to review the CT scans for 8 of the 10 patients, with only a radiologist’s interpretation was available for the remaining 2. All patients had head CT evidence of a penetrating skull injury. Five patients sustained penetrating skull lesions on the left side with 3 on the right and 2 in both regions; 50% of the children had multiple skull fractures. Ninety percent of patients had pneumocephalus, which in all cases were in the area of the fracture (fig. 1, 2). The patient without evidence of pneumocephalus was 1 of the 2 for whom we only had a radiology report available. In relation to the scalp injuries, 1 patient had a fracture in an area different from the scalp laceration. Three patients had extra-axial hematomas, and 2 of these were the youngest in the series (table 1). In the literature, 14 patients had a CT scan, but one of these CT scans was taken only after a dural tear became evident in surgery. Five had only an XR performed as the main diagnostic imaging tool. One had an MRI without having a CT scan. One case report did not have a comment on imaging. Five cases were reported as pneumocephalus. Management The average length of the hospital stay in our series was 2.9 days with a range of 1–9 days. Forty percent of the patients were admitted to the pediatric intensive care unit (PICU), and 1 patient had evidence of a cerebrospinal fluid (CSF) leak. In the literature, the mean length of stay was 22.1 days, and the median stay was 21 days. Surgery At our institution, 5 of 10 patients underwent neurosurgical interventions (i.e. wound debridement, removal of comminuted fracture bones, and primary repair of a dura mater laceration), one of which was performed by a pediatric general surgeon. Debridement and irrigation were the most commonly performed procedures; none of the extra-axial hemorrhages required surgical evacuation. Dural repair was performed in only 1 case; hemostasis of a mastoid emissary bleeding vein was necessitated in another case. None of the patients required a return to the operating room. All patients sustained additional lacerations of the head, face or neck other than the intracranial lesion as follows: 2 patients in the neck, 6 in the face, 5 in the ears, and 5 in the eyes/orbits/eyelids. Eight patients required nonneurosurgical procedures for these lacerations, which were performed by a plastic surgeon in 3 cases, an ophthalmologist in 5 cases, Steen/Ravin/Timmons/Kershenovich
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potential inclusion in this study, which consisted of patients aged 0–18 years who sustained a head and/or face injury with evidence of a penetrating skull injury on head/brain CT scan images. A total of 10 patients were identified and included in the study. The Geisinger Health System Institutional Review Board approved protocol 20110107 (federal-wide assurance 00000063) for this study.
Table 1. Institutional clinical data and management Gender/age Dog Dog breed at attack, owner months
Location of skull fracture
Patient 1 F/11.5
Parent Mixed
Patient 2 M/29
Uncle
Patient 3 M/19.9
Parent Rottweiler
Patient 4 M/3
Left occipital Parent Alaskan malamute/ Australian shepherd mix
Patient 5 F/116.7
No Bull report mastiff
Patient 6 M/33.2
Pneumocephalus
Extra-axial hemorrhage
Initial antibiotic (added antibiotic)
Left temporal, Left frontal, left nasal bone, left orbit inferolateral margin of left orbit
Left frontal
Augmentin
Right temporal
Right temporal
None
Ancef
Bilateral parietal
Bilateral parietal
None
Left occipital
Switched antibiotic
PICC Total days Surgical line of antibiotic management treatment
No
10
Repair of dural tear with galea. Washout
No
11
Comminuted bones removed. Washout
Clindamycin
No
9
None
Left occipital
Unasyn
No
1
None
Right parietal, Left occipital left occipital, right temporal
None
Unasyn
Vancomycin, Meropenem
Yes
18
Hemostasis of mastoidal emissary vein. Washout
Friend Saint bernard
Parasagittal left frontal
Left orbit
None
Unasyn and nafcillin
Meropenem
Yes
16
Washout
Patient 7 F/29.2
Aunt
Right parietal
Right parietal
None
Unasyn
Meropenem, Augmentin
Yes
18
Washout in the ED
Patient 8 F/35.9
Parent Pit bull
Left temporal, Left temporal and left frontal left petrous bone, left occipital
Left temporal Ampicillin Unasyn, (gentamicin) Meropenem (Flagyl)
Yes
10
Primary dural repair; comminuted bones removed. Washout
Patient 9 M/48.6
Uncle
German shepherd
Base of skull, right superior orbit
Right superior orbit
None
Unasyn
Augmentin
Yes
14
None
Patient 10 M/21.8
Aunt
Doberman Left frontal pinscher
None
None
Ceftriaxone
Cefazolin
No
1
None
Pit bull
Saint bernard
Unasyn, Augmentin
an otolaryngologist in 5 cases, an oral and maxillofacial surgeon in 1 case, and a pediatric surgeon in 1 case. Two patients did not require any procedures as their lacerations were posterior to the ear, and neurosurgery was the only consulted service for these cases. Overall, the neurosurgery service was consulted in 9 of the 10 cases. On follow-up after hospital discharge, none of the children had developed brain abscesses, extra-axial empyemas or meningitis.
All 21 patients reported in the literature required neurosurgical intervention, with 9 of them receiving intervention more than 24 h after their injury. Seven of these were inadequately evaluated initially, and the diagnosis of an intracranial injury was missed. Nine of the 21 patients were initially managed with only debridement, irrigation and/or repair of cutaneous lacerations, with 8 patients requiring a second intervention. Of these patients, 6 had a missed initial diagnosis and 5 required elevation of depressed fractures.
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PICC = Peripherally inserted central catheter; ED = emergency department.
190
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Steen/Ravin/Timmons/Kershenovich
8
15
9 12 2 8
24
0.5
0.5
Wilberger [17], 1981
Cowie [7], 1983
Wilberger [18], 1983
Sutton [14], 1984
Kenevan [8], 1985
Steinbok [13], 1985
24 36
24
20
Pinto [12], 2008
Santana-Montero [2], 2009
Burns [6], 2011
F
F
M F
F
F
F
M
M
F F M F
F
F
F M
F
F
F
No
No
No No
No
Yes
No
No
No
No No No Yes
No
Yes
Yes No
No
No
No
Gender Intracranial hematoma
N/A = Not available; d/c = discharge.
18
Iannelli [3], 2005
0.5
8 4
Pinckney [11], 1980
19
Klein [9], 1978
13
18
O’Riordan [10], 1976
Watson [16], 1980
Age, months
First author and year
Yes
N/A
Yes Yes
Yes
Yes
Yes
Yes
Yes
Yes No No Yes
Yes
Yes
N/A N/A
N/A
N/A
Yes
Dural tear
Table 2. Literature review of intracranial dog bite injuries
No
Abscess (late)
No No
No
Meningitis, followed by abscess (late) No
Meningitis (late)
Abscess (late)
Yes No No No
Yes
No
No No
Meningitis
Abscess (late)
No
Infections
N/A
No
N/A N/A
N/A
N/A
Yes (CSF)
N/A
No; taken 4 days after event
Yes (wound) Yes N/A N/A
Yes (wound)
N/A
N/A N/A
Yes (CSF)
No
N/A
Initial cultures
N/A
N/A
N/A N/A
N/A
N/A
Pasteurella (meningitis)
Meningitis prophylaxis, unspecified (N/A)
Ceftriaxone (7 days)
Oxacillin, ceftriaxone, metronidazole (14 days) Oxacillin, ceftriaxone, metronidazole (14 days)
Cephalosporin and vancomycin (15 days)
Penicillin and cloxacillin (1 week)
Chloramphenicol and ampicillin (9 and 14 days postoperatively, respectively)
Prophylactic antibiotics (unspecified); followed by penicillin and kanamycin (both N/A)
Cephalexin (4 days); followed by chloramphenicol and oxacillin with discovery of abscess (N/A); followed by penicillin (3 weeks)
Peptococcus species
No growth (cultured from CSF on day 5 due to fever). Gram stain was positive for bacteria
Chloramphenicol and oxacillin (10 days) Oxacillin (10 days) Oxacillin (10 days) Chloramphenicol and oxacillin (10 days)
Penicillin and flucloxacillin (N/A)
Chloramphenicol and oxacillin (7 days)
N/A N/A
Penicillin G (6 weeks)
None; unspecified antibiotics later given for abscess (N/A)
Ampicillin upon d/c (1 day); followed by penicillin 1 day after the event (N/A)
Initial antibiotics (length of treatment)
Klebsiella and Proteus None N/A N/A
S. aureus, E. cloacae
N/A
N/A N/A
Pasteurella
Pasteurella cultured from abscess 3 weeks after event
N/A
Cultures at infection
Fig. 1. Head CT, bone window of patients 1 (coronal view), 2, 3 and 5 (axial view), showing the fractures and pneumocephalus. The star symbol shows the area of interest.
Fig. 2. Head CT, bone window of patients 6, 7 (axial view), 8 (sagittal view) and 9 (coronal view) showing the
fractures and pneumocephalus. The star symbol shows the area of interest.
Antibiotics In our series, all patients were treated with antibiotics and 50% were discharged home with a peripherally inserted central catheter line for continued parenteral antibiotic therapy. Forty percent of patients were treated at least once with amoxicillin/clavulanic acid. Seventy percent of patients were initially treated with either ampicillin or ampicillin/sulbactam. Of these, 3 were switched to meropenem by the infectious disease consultant. One patient was treated with clindamycin due to a known amoxicillin allergy. Six patients were treated with two to three antibiotics simultaneously. Only 40% of patients were maintained on the same initial antibiotic type, whereas 40% had their therapy changed once, and 20% were changed three times. The average number of antibiotics Pediatric Intracranial Dog Bites
used was 2.4 with a range of 1–5. The mean duration of antibiotic therapy was 10.8 days with a range of 1–18 days (table 1). Only 1 patient had a culture taken from the wound that showed no bacterial growth. In the literature review, as summarized in table 2, 18 of 21 patients were reported to receive antibiotic treatment during the course of their hospital admission; three case reports did not document initial antibiotic therapy. The median length of the initial antibiotic treatment was 10 days. Cultures were reported to have been taken in only 9 cases, with 5 at the time of admission (only 4 grew microorganisms). Of the 4 patients presenting with infections, cultures grew Pasteurella (treated with penicillin G in 1 patient and chloramphenicol and ampicillin in another) Klebsiella and Proteus (treated with chloramphenicol and oxacillin), and S. aureus and Enterobacter cloacae (treated with penicillin and flucloxacillin). An inadequate initial evaluation in 4 patients resulted in 3 of them developing brain abscesses; cultures grew Pasteurella (treated with unspecified antibiotics) and Peptococcus species (treated with chloramphenicol and oxacillin), and 1 case report did not contain documentation of the microorganism or the treatment. The patient with meningitis developed fever on the 5th day of his hosPediatr Neurosurg 2014–15;50:187–195 DOI: 10.1159/000431179
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Fourteen patients were reported to have dural lacerations or CSF leaks. In addition, 4 more ultimately had meningitis (n = 1) or brain abscesses (n = 3; 2 were drained surgically), which means that in retrospect they did have a dural transgression. Ten patients required dural repairs of which only six were performed within 24 h. Four patients required evacuation of intracranial hematomas, which were all performed within 24 h of injury.
Laboratory Tests In our series, 9 patients had hemoglobin documented at the time of admission and 4 showed mild anemia. Eight patients had a documented white cell count; 5 patients had leukocytosis, of which 2 had a differential cell analysis showing a mildly elevated neutrophil count. Seven patients had a basic metabolic panel; only 2 of these patients showed abnormal values, and both had hyperkalemia and hyperglycemia. All had normal plasma sodium, creatinine, calcium and BUN (blood urea nitrogen). Immunizations Two of the patients treated by us received a tetanus vaccine. None were documented to have received a rabies vaccine. Follow-Up and Outcomes In our series, 6 of the 10 patients were seen at least once in the neurosurgery outpatient clinic after discharge, and 9 had at least one documented outpatient clinic visit with a nonneurosurgical provider within the system with enough information to be able to assess the gross neurological condition. The mean follow-up after hospital discharge was 30 months (median 26 months, range 11–36). The average time from hospital discharge to the first follow-up visit was 24 days (range 3–50). None of the followed patients had complications. In the literature review, the mean follow-up for 11 patients with documented outpatient clinic visits after discharge was 6 months (range 2–27). The other 5 patients had some follow-up information as well. During the follow-up appointments 3 patients were diagnosed with late infections – 2 had hemiparesis and 1 had persistent peripheral nerve palsies. Two patients had seizures, including 1 during admission who also had disseminated intravascular coagulation, a cardiac arrest, and died.
Discussion
We found only 21 pediatric cases of intracranial dog bite injuries reported in the literature. Seventeen were single case reports with three reporting 2 cases [11–13, 15], and one reporting 4 cases [18]. In contrast to these previously reported cases, our patients were slightly older 192
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(median of 29 months compared to 13 months). Although infants are more susceptible to intracranial dog bite injuries because of their thin skulls, it is likely that they are not left unattended with dogs as often as older children. Furthermore, the height of toddler-aged children most likely places them at the level of a medium- to large-sized dog’s mouth, which may explain why they are also at risk. All dog breeds in our study and most in the literature review cohort were of medium to large size. Our medical center has been continuously accredited as an adult level 1 regional trauma center since 1984, and in 1996 it acquired additional qualifications in pediatric trauma. In 2008, the Children’s Hospital was accredited as a level 2 pediatric trauma center. Overall, Geisinger Medical Center and Janet Weis Children’s Hospital have acted as the main trauma center in the region for over 20 years, serving an estimated population of 2.5 million habitants. With this in mind, for over 19 years, we have treated 10 patients with documented intracranial injuries from dog bites for a rough prevalence of 1 case every 2 years. So, although uncommon, this is a pathology that all pediatric neurosurgeons will encounter in their careers several times. Three patients in our sample sustained extra-axial hemorrhages. We believe that the commonality of these injuries was the relative thinness of the skull bone, either due to young age or the anatomic location, as two occurred in infants (frontal and occipital bones) and the other in the temporal bone of a toddler. Two of these patients sustained a dural laceration. Regardless of whether the victim was an infant or a toddler, it is our opinion that there should be a low threshold for wound exploration when the injury involves the temporal bone, as it will be more prone to be associated with a dural laceration with or without an extra-axial hemorrhage. We also recommend exploration and debridement for comminuted injuries, because they are more likely to be associated with dural lacerations [19]. In the reviewed literature, a high frequency of major infectious complications was noted with 8 out of 21 (38%) patients experiencing infections and 14 out of 21 (66%) patients having dural lacerations (table 2). Five of the 8 patients who experienced infectious complications had a documented dural laceration. We suspected that 3 additional patients had a dural laceration as 2 developed a brain abscess and 1 had meningitis, but patients were not reported to have a dural laceration at the initial injury. In contrast, only 2 of 10 (20%) patients in our series experienced dural lacerations. They both underwent early CSF leak repair and neither had an infection. When our series was included in the literature review the rate of inSteen/Ravin/Timmons/Kershenovich
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pital admission and cultures were taken to confirm the diagnosis of meningitis but without bacterial growth. The patient was treated with high doses of i.v. penicillin and i.v. kanamycin.
infectious disease service may help avoid multiple changes in the antibiotic regimen. The median duration of antibiotic therapy in our series was 10.5 days with a range of 1–18 days. We recommend completing a 10- to 14-day regimen depending on the clinical course. We also recommend that a tetanus vaccine be given as per the most current immunization schedule. Four of the cases published in the reviewed literature reported intracranial hematomas, all of which were surgically evacuated (table 2). Thirty percent of our patients had extra-axial hemorrhages, none of which required surgical intervention. When including the literature cases, the frequency of having an intracranial extra-axial hemorrhage following an intracranial dog bite injury is 22.6% (table 2). Though not published, anecdotal catastrophic and even fatal cases of intracranial injuries from dog bites exist and, thus, like other types of injuries, these can range from mild to severe; our series may not reflect this entire range. If there is a suspicion of a major vascular injury, such as a large hematoma, or if there is an increased risk of one that is due to the location of penetration, then surgical management should be in accordance with usual neurosurgical practice. We are aware of the discrepancy between our results and the literature review. We do not pretend to state that intracranial dog bite injuries are in general mild, but we also bring another perspective to the published literature in that many of these injuries, when adequately identified and treated promptly, will result in positive outcomes without complications as long as the injury is not in a bad location such as a sinus or is deep enough to lacerate important feeding arteries or draining veins. We think that it is essential to suspect a possible penetrating injury to the skull when a scalp laceration is present and, therefore, recommend an aggressive imaging investigation with a head CT. Missing the diagnosis can prevent an early washout and adequate antibiotic treatment which can prevent later infections. Scalp lacerations generally tend to have significant bleeding. This can be dangerous in young children who have low blood volumes because it places them at higher risk for anemia from these injuries. Young children with large or extensive lacerations and significant blood loss merit observation in the PICU setting. In our series, 40% of the children spent their first night of hospitalization in the PICU. Of these, 3 had extra-axial hemorrhages. The remaining patient had a parasagittal fracture and required debridement. Interestingly, none of our patients or the 21 in the literature review experienced hemorrhages as a result of injury to the superior sagittal sinus or the transverse sinuses.
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fection and dural laceration following an intracranial dog bite dropped to 25.8 and 51.6%, respectively. Considering the lower rate of infections and dural lacerations in our series as compared to the literature, we believe that there may be a selection bias in the reporting of intracranial dog bite injuries in children. It is likely that most patients have an uneventful course similar to our sample and their cases have not been published. Additionally, the age difference between our cases and those previously reported in the literature could also explain the disparity of infectious complications between these two groups. Our relatively older sample of patients would be expected to have a more fully developed immune system, which may have protected them from infectious complications as compared to younger infants. Considering the high risk of infection reported in the literature, it is not surprising that our physicians have taken great care to prevent infections. Sixty percent of our patients underwent wound washout prior to wound closure. All 10 of our patients were prescribed empiric broad spectrum antibiotics. This management is consistent with the literature (table 2). Although initiating antibiotics in the emergency department may also contribute to better outcomes and fewer infectious complications, it would appear that a randomized controlled study is needed to assess whether prophylactic antibiotics are needed for these injuries. Unfortunately, such a study is unrealistic not only because of the small number of cases, but also because of reports describing life-threatening conditions such as brain abscesses and meningitis [2, 8, 9, 11, 13, 14]. Despite the risk of infection, current recommendations for antibiotic prophylaxis remain controversial. Smith et al. [20] suggested that there is little evidence of benefit for the use of antibiotics for dog bite injuries. However, other authors have recommended empiric antibiotics for any dog bite injury with bone involvement, especially if there is CSF inoculation [4, 21–23]. When infection does occur, P. multocida is isolated in culture in more than 50% of cases, followed by Staphylococcus (25%) and Streptococcus (15%) [4]. Only 40% of our patients were maintained on the same initial antibiotic throughout their hospital stay. Antibiotics were changed multiple times prior to consultation with the pediatric infectious disease specialist. There is a lack of consensus in the literature on the optimal regimen of antibiotic coverage. Based on our experience, review of the literature and knowledge of the common canine oral microorganisms, we recommend that patients be treated with a broad-spectrum antibiotic with effective CNS penetration, such as meropenem. Early consultation with the
Since pneumocephalus was a consistent finding on imaging (90%) in our study (table 1), we recommend that all children with a dog bite wound to the head should be evaluated with a brain CT. None of our patients had seizures, and only 2 patients in the literature review experienced seizures. We suggest that evidence-based guidelines regarding seizure prophylaxis for patients with extra-axial hematomas, parenchymal hematomas and depressed skull fractures be followed [24, 25]. We have found that 8 patients in the literature review were initially erroneously evaluated; fractures were missed on imaging in 3 patients, and 5 patients were discharged from the hospital on the same day after treatment for superficial wounds only. They were readmitted from 1 day to 2 months after the inciting event. Six of the 8 patients had complications – 4 had infections and 2 had a CSF leak. Follow-up for all patients in our series and those reviewed from the literature was heterogeneous and lacked an organized structure. Our study’s results indicate that there are grossly two types of patients: those with adequate diagnosis and aggressive management, and those with a missed or delayed diagnosis. The former group tends to have good outcomes and few complications, whereas the later was associated with high complication rates. In the face of these observations, we recommend a structured follow-up after hospital discharge, consisting of a wound check and clinical assessment at the neurosurgical clinic, as well as a visit with the infectious disease specialist at 1 and 3 weeks after discharge, followed by neurosurgery follow-up at 2 and 4 months after discharge. Follow-up brain imaging is at the discretion of the neurosurgeon, individualized upon the patient’s presentation and risk of developing a brain abscess. With regards to preventing injuries to the cranium from dog bites, we believe that educating families with
dogs to avoid leaving infants and young children alone or in close proximity to a dog is reasonable, especially those with medium- to large-sized dogs. Our study is limited by virtue of the small sample and being a retrospective case review in a single institution. However, the authors believe that our results and observations will be helpful to those providers who are seeking advice for the management of intracranial dog bite injuries.
Conclusions
Intracranial injuries from dog bites in children should be thoroughly investigated and aggressively managed by surgical debridement and irrigation in cases where a scalp laceration or dural tear is present. A head CT scan without contrast is recommended for all children sustaining dog bites to the head. Surgical exploration should be undertaken when there is evidence of comminuted fractures on imaging studies. A broad-spectrum antibiotic should be initiated early (within 24 h of the injury) and utilized for a relatively short period of time of about 10–14 days. Follow-up in the neurosurgery clinic can help to identify early subacute or chronic infectious complications. Acknowledgements We express a special thank you to Marian Repella Kozak for her invaluable editorial assistance.
Disclosure Statement The authors have no conflicts of interest to declare.
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