- Email: [email protected]
The incidence of long-term hypertension in children after high-grade renal trauma
Journal of Pediatric Surgery xxx (2015) xxx–xxx
Contents lists available at ScienceDirect
Journal of Pediatric Surgery journal homepage: www.elsevier.com/locate/jpedsurg
The incidence of long-term hypertension in children after high-grade renal trauma Molly E. Fuchs ⁎, Ross E. Anderson, Jeremy B. Myers, M. Chad Wallis Department of Surgery, Division of Urology, University of UT, USA
a r t i c l e
i n f o
Article history: Received 17 March 2015 Received in revised form 4 May 2015 Accepted 12 May 2015 Available online xxxx Key words: Hypertension Renal Trauma Kidney
a b s t r a c t Introduction: It is generally accepted that there is a risk of hypertension after renal trauma, particularly in highgrade and devascularizing injuries. Hypertension following renal trauma is estimated to occur in five percent of adults, however, the incidence is unknown in the pediatric population. Materials and methods: We performed a retrospective review of all pediatric trauma patients at Primary Children’s Hospital in Salt Lake City, Utah between 2002 and 2012. We included all children age ≤17 years old with American Association for Surgery of Trauma (AAST) grade 3–5 renal injury. Hypertension was defined as persistent hypertension that required anti-hypertensive medications. Our primary outcomes were incidence of hypertension during the acute trauma and in long-term follow. Results: A total of 62 children were identified with AAST grade 3–5 renal injuries during our study period. Follow up blood pressures were recorded in 36 (58%) of these children with a median follow of 4.1 years (IQR 2.1–5.1 years) after trauma. Four children (6.5%) were identified to have some degree of hypertension while hospitalized after trauma and started on anti-hypertensive medication. Two out of these four children remained on hypertensive medication at follow up, while the remaining two children’s hypertension resolved. No children who were normotensive in the immediate post-trauma period, developed delayed hypertension during longterm follow up. Conclusions: There is a low risk of developing hypertension following severe renal trauma in the pediatric population. Patients who develop long-term problems with hypertension after renal trauma manifest it during the initial hospitalization, rather than subsequently during the long-term. © 2015 Elsevier Inc. All rights reserved.
Renal trauma accounts for 1.4% to 3.25% of injuries to adult trauma patients, with an incidence of 4.9 per 100,000 population [1,2]. Children are also at high risk of renal injury, but the rate of injury has not been well defined [3]. According to the national trauma databank, less than 10% of injuries in the pediatric population are due to a penetrating mechanism, 79% of injuries are grade 3 or less, and only 12% of patients are admitted to a pediatric hospital [4]. High-grade renal injuries result in injury to the renal parenchyma, which leads to compromised function. It is generally accepted that there is a risk of long-term hypertension after renal trauma, particularly high-grade and devascularizing injuries, but the incidence has never been published in children. It is thought that the mechanism for post-traumatic hypertension is an up-regulation of the renin–angiotensin system, but this remains largely theoretical [5]. In adults, retrospective studies estimate the incidence of hypertension following severe renal trauma between 4% and 5%, and the onset of hypertension occurred between 2 and 8 weeks after injury [6,7]. In one of the only pediatric studies that examined renal injury of any grade and the risk of long-term hypertension, the authors reported that none of the children were hypertensive at three ⁎ Corresponding author at: Department of Surgery, Division of Urology, School of Medicine, 30 N 1900 E, Salt Lake City, Utah 84132. Tel.: +1 801 581 7304. E-mail address: [email protected] (M.E. Fuchs).
months post-injury [8]. The literature on long-term follow up after renal trauma is very limited because, in general, follow up after trauma is a challenging and outcomes are poorly defined. The purpose of our study was to evaluate a large cohort of highgrade pediatric renal trauma patients and determine the incidence of hypertension. Our secondary aims were to understand if hypertension developed de novo after the renal injuries or was evident at the time of injury, and if present at the time of injury, whether it would resolve over time or require long-term antihypertensive therapy. 1. Materials and methods 1.1. Study population After Institutional Review Board approval, a retrospective review was performed of all pediatric trauma patients at Primary Children’s Hospital in Salt Lake City, Utah between 2002 and 2012. We included all children age ≤17 years old with American Association for Surgery of Trauma (AAST) grade 3–5 renal injuries. All children had a thorough chart review including trauma hospitalization and follow up visits. Clinical variables reviewed and reported in this study include: age, sex, mechanism of injury, injury severity score (ISS), renal trauma grade, hospital length of stay, intensive care unit length of stay, the
http://dx.doi.org/10.1016/j.jpedsurg.2015.05.014 0022-3468/© 2015 Elsevier Inc. All rights reserved.
Please cite this article as: Fuchs ME, et al, The incidence of long-term hypertension in children after high-grade renal trauma, J Pediatr Surg (2015), http://dx.doi.org/10.1016/j.jpedsurg.2015.05.014
2
M.E. Fuchs et al. / Journal of Pediatric Surgery xxx (2015) xxx–xxx
number and types of intervention, the presence of hypertension during the acute trauma hospitalization and at long-term follow up (defined below). 1.2. Patient follow up All patients who met inclusion criteria were sent an IRB approved letter informing them of the study and requesting consent for direct telephone contact. The parents of the children were then contacted by phone, and verbal consent was obtained for this study. The patient’s pediatrician’s office was then contacted, and they provided the most recent blood pressure from a well-child visit. Measurement from a well child visit was chosen in order to help control for blood pressure variation due to acute illness or pain. 1.3. Hypertension definition Any child who was persistently hypertensive and required antihypertensive medication while in the hospital or on discharge was identified as hypertensive. Prior to diagnosing the patient with hypertension the patient’s pain had to be controlled. All trauma patients with renal injuries at Primary Children’s Hospital were instructed to follow up regularly with their pediatricians to have their blood pressure checked. Follow up blood pressures were evaluated by patient age and gender, and a child was considered hypertensive if either the systolic or diastolic pressure was greater than the 90th percentile for age and gender. 1.4. Theory/calculation Simple descriptive analyses were performed to characterize the population using Stata (V12). The incidence of hypertension was calculated for our cohort of patients with long-term follow up hypertension data. 2. Results A total of 62 children were identified with AAST grade 3–5 renal injuries during our study period. There were 36 (58%) males, and the average age for the cohort was 10.2 years at the time of trauma. The median injury severity score was 18.7 (IQR 10–25). Of these 62 injuries, 21 were grade three, 40 were grade four, and only one was grade five (Table 1). Eight patients with grade 4 renal injuries required surgical intervention for urinary extravasation, and none of the patients required nephrectomy, blood transfusion, or other intervention for hemorrhage. Four children (6.5%) were identified to have some degree of hypertension while hospitalized after trauma. None of these children underwent an operative intervention. Table 2 summarizes the clinical course of these hypertensive patients. All four children (6.5%) required one anti-hypertensive medication at the time of discharge. Only one child required dual anti-hypertensive therapy while in the hospital, and the most common medications used were lisinopril, amlodipine, and losartan. The remaining 58 (93.5%) children were normotensive throughout their hospitalization and at the time of discharge. Long-term follow up and recent blood pressure measurements were obtained in 36 (58%) of the patients, including all four hypertensive
Table 1 Severe renal trauma patient characteristics. AAST Renal Injury Grade
Number (%)
3 4 5
21 (34%) 10.6 40 (65%) 9.5 1 (1%) 2.3
a
Age Sex (mean) (% Male)
Average LOS (Days)
11 (52%) 6 24 (60%) 7.7 1 (100%) 17
7 stents, 1 percutaneous nephrostomy tube.
ISS Operative (Mean) Intervention 15 20.2 27
0 8a 0
children. The median follow up was 4.1 years (IQR 2.1-5.1 years) after trauma. None of the children with normal blood pressures during the initial hospitalization subsequently developed hypertension or required anti-hypertensive medications at follow up. There were no pre-existing medical renal diseases identified in our study’s hypertensive children. Only one of the five hypertensive children identified was obese, BMI 33 at time of presentation. This child had discontinued lisinopril at the time of follow-up, which argues against pre-existing medical renal hypertension associated with obesity. Two (3.2%) children remained on anti-hypertensive medication at the time of follow up. These two children did have high injury severity scores. One child, with a score of 29 did not require surgery during his hospitalization, and sustained the following injuries: splenic laceration, rib fractures, pulmonary contusion with pneumohemothorax, humerus and pelvic fractures. The other child, had an ISS of 50, did not require surgery, and sustained: a pulmonary contusion with pneumohemothorax, lumbar and thoracic vertebral fracture, and an injury to the pancreas. Univariate analysis was attempted to identify predictive clinical factors for the development of hypertension following pediatric renal trauma. There were no significant factors that were associated with development of hypertension in the 4 patients, including: age, sex, grade, mechanism of injury, or operative intervention. 3. Discussion The incidence of pediatric hypertension after severe renal trauma in our population was 6.5%. This is the first pediatric study reporting the incidence of intra-hospital and long-term hypertension following severe blunt renal trauma. Two out of 36 patients with long-term blood pressure follow up required long-term anti-hypertensive medication. The only prior study to examine functional outcomes in children following renal trauma used 15 patients with grade 3 or higher injury, and reported zero cases of hypertension at three months and one-year follow-up [8,9]. The mechanism for hypertension after trauma is not well understood, but many have suggested that it is a result of up-regulation of the renin angiotensin system [4,5]. In both children and adults, between 82% and 95% of renal injuries are caused by blunt trauma in the United States [2,4]. The presence of preexisting hypertension in adult renal trauma patients is a potential confounder, making it difficult to accurately identify patients with hypertension directly related to the traumatic event. In one study where 9 of 31 patients experienced post-trauma hypertension 80% had a positive family history of arterial hypertension [10]. In contrast, pediatric populations generally do not have pre-existing hypertension, which allows for a potentially more accurate depiction of the association between renal trauma and hypertension. Traditionally high-grade injuries are classified as grade 4 or 5. We chose to include grade 3 injuries in our definition of high grade because two of the patients that sustained kidney injuries severe enough to develop hypertension were classified as grade 3. The children in our study who developed hypertension were identified during their initial trauma hospitalization, and no additional children had elevated blood pressures at follow-up. This finding suggests that if hypertension is going to present after pediatric renal trauma, then it is more likely to occur in an acute fashion. Worldwide there is not a consensus for post-traumatic blood pressure monitoring; for instance, The European Urologic Association recommends monitoring for renovascular hypertension for at least a year following injury [11]. An inherent shortcoming of population-based research in trauma is the lack of follow-up data. A major strength of this study is the longterm follow-up we acquired by contacting both patients and their pediatricians. With a median follow-up of over four years we would argue that if hypertension was going to develop after traumatic renal injury it would have occurred by this time. The lengthy follow up also provided ample time to demonstrate that half of the hypertensive
Please cite this article as: Fuchs ME, et al, The incidence of long-term hypertension in children after high-grade renal trauma, J Pediatr Surg (2015), http://dx.doi.org/10.1016/j.jpedsurg.2015.05.014
M.E. Fuchs et al. / Journal of Pediatric Surgery xxx (2015) xxx–xxx
3
Table 2 Hypertensive patient summary. Patient Age (yrs)
Sex Mechanism of Injury
AAST Grade
Length of Stay (Days)
ISS Devascularization Injury Present
Anti-HTN at Discharge
Time to Follow-up (yrs)
Anti-HTN at Follow-up
1 2 3 4
M M M F
3 5 4 4
35 17 23 17
29 27 50 16
Lisinopril Amlodipine Lisinopril Lisinopril
4 4.58 4.25 0.25
Lisinopril No Lisinopril No
3.4 2.8 13.5 5.9
Pedestrian vs Auto Fall From Height Fall From Height Motor Vehicle Collision
No Yes No No
patients had their blood pressure normalize by the time of follow up. This suggests that the hypertension following the injury, likely mediated by the renin angiotensinogen system up-regulation, can be temporary as evidenced by 50% resolution in our series. One shortcoming of this study is that we do not have functional outcomes at the same time as long-term blood pressure data. There is one pediatric study that showed at one year follow-up after renal injury, grade 4 and 5 injuries showed 42% and 32% differential function respectively on DMSA scan. Another limitation is that while the current study is the largest cohort of high-grade pediatric renal injury with long-term blood pressure measurements, the study size did not allow us to calculate predictive factors for developing hypertension. Also, our study is subject to recall bias due to the phone interview with parents regarding duration, compliance, and use of hypertensive medication. We do not have pre-trauma data regarding the presence of pre-existing hypertension. This is a potential confounder, but much less of a factor in the pediatric population compared to adult trauma. We chose to use the last well child blood pressure measurement because many of the trauma patients receive their primary care outside of our tertiary medical center, and therefore we do not have access to every blood pressure recorded after a child’s injury. Interestingly, there does not seem to be a relationship between degree of injury and risk of hypertension. While our numbers are quite small, one would assume that the higher risk injuries pose a higher risk of hypertension requiring medication, but the only grade 5 injury in our series, only required anti-hypertensive therapy for a temporary period of time. In addition, 1 patient with a grade 3 injury (a relatively low risk injury) still developed hypertension after injury.
4. Conclusions The risk of hypertension after high-grade pediatric renal trauma is real. However, the risk of any degree of hypertension is low at 6.5%, and the risk of long-term hypertension is only 3.5%. Our study also suggests that there is no apparent risk of de novo hypertension after renal trauma if there is no hypertension present during the acute injury period. References [1] Santucci RA, Wessells H, Bartsch G, et al. Evaluation and management of renal injuries: consensus statement of the renal trauma subcommittee. BJU Int, vol. 93. Blackwell Science Ltd; 2004 937–54. [2] McGeady JB, Breyer BN. Current epidemiology of genitourinary trauma. Urol Clin North Am 2013;40:323–34. [3] Brown SL, Elder JS, Spirnak JP. Are pediatric patients more susceptible to major renal injury from blunt trauma? A comparative study. J Urol 1998;160:138–40. [4] Grimsby GM, Voelzke B, Hotaling J, et al. Pediatric urology demographics of pediatric renal trauma. J Urol 2014;192:1498–502. [5] Delarue A, Merrot T, Fahkro A, et al. Major renal injuries in children: the real incidence of kidney loss. J Pediatr Surg 2002;37:1446–50. [6] Knudson MM, Harrison PB, Hoyt DB, et al. Outcome after major renovascular injuries: a Western trauma association multicenter report. J Trauma Inj Inf Crit Care 2000;49:1116–22. [7] Montgomery RC, Richardson JD, Harty JI. Posttraumatic renovascular hypertension after occult renal injury. Trauma Inj Inf Crit Care 1998;45:106–10. [8] Keller MS, Eric Coln C, Garza JJ, et al. Functional outcome of nonoperatively managed renal injuries in children. Trauma Inj Inf Crit Care 2004;57:108–10. [9] Keller MS, Green MC. Comparison of short- and long-term functional outcome of nonoperatively managed renal injuries in children. J Pediatr Surg 2009;44:144–7. [10] Pereira Júnior GA, Muglia VF, Santos Dos AC, et al. Late evaluation of the relationship between morphological and functional renal changes and hypertension after nonoperative treatment of high-grade renal injuries. World J Emerg Surg 2012;7:26. [11] Lynch TH, Martínez-Piñeiro L, Plas E, et al. EAU guidelines on urological trauma. Eur Urol 2005;47:1–15.
Please cite this article as: Fuchs ME, et al, The incidence of long-term hypertension in children after high-grade renal trauma, J Pediatr Surg (2015), http://dx.doi.org/10.1016/j.jpedsurg.2015.05.014
Contents lists available at ScienceDirect
Journal of Pediatric Surgery journal homepage: www.elsevier.com/locate/jpedsurg
The incidence of long-term hypertension in children after high-grade renal trauma Molly E. Fuchs ⁎, Ross E. Anderson, Jeremy B. Myers, M. Chad Wallis Department of Surgery, Division of Urology, University of UT, USA
a r t i c l e
i n f o
Article history: Received 17 March 2015 Received in revised form 4 May 2015 Accepted 12 May 2015 Available online xxxx Key words: Hypertension Renal Trauma Kidney
a b s t r a c t Introduction: It is generally accepted that there is a risk of hypertension after renal trauma, particularly in highgrade and devascularizing injuries. Hypertension following renal trauma is estimated to occur in five percent of adults, however, the incidence is unknown in the pediatric population. Materials and methods: We performed a retrospective review of all pediatric trauma patients at Primary Children’s Hospital in Salt Lake City, Utah between 2002 and 2012. We included all children age ≤17 years old with American Association for Surgery of Trauma (AAST) grade 3–5 renal injury. Hypertension was defined as persistent hypertension that required anti-hypertensive medications. Our primary outcomes were incidence of hypertension during the acute trauma and in long-term follow. Results: A total of 62 children were identified with AAST grade 3–5 renal injuries during our study period. Follow up blood pressures were recorded in 36 (58%) of these children with a median follow of 4.1 years (IQR 2.1–5.1 years) after trauma. Four children (6.5%) were identified to have some degree of hypertension while hospitalized after trauma and started on anti-hypertensive medication. Two out of these four children remained on hypertensive medication at follow up, while the remaining two children’s hypertension resolved. No children who were normotensive in the immediate post-trauma period, developed delayed hypertension during longterm follow up. Conclusions: There is a low risk of developing hypertension following severe renal trauma in the pediatric population. Patients who develop long-term problems with hypertension after renal trauma manifest it during the initial hospitalization, rather than subsequently during the long-term. © 2015 Elsevier Inc. All rights reserved.
Renal trauma accounts for 1.4% to 3.25% of injuries to adult trauma patients, with an incidence of 4.9 per 100,000 population [1,2]. Children are also at high risk of renal injury, but the rate of injury has not been well defined [3]. According to the national trauma databank, less than 10% of injuries in the pediatric population are due to a penetrating mechanism, 79% of injuries are grade 3 or less, and only 12% of patients are admitted to a pediatric hospital [4]. High-grade renal injuries result in injury to the renal parenchyma, which leads to compromised function. It is generally accepted that there is a risk of long-term hypertension after renal trauma, particularly high-grade and devascularizing injuries, but the incidence has never been published in children. It is thought that the mechanism for post-traumatic hypertension is an up-regulation of the renin–angiotensin system, but this remains largely theoretical [5]. In adults, retrospective studies estimate the incidence of hypertension following severe renal trauma between 4% and 5%, and the onset of hypertension occurred between 2 and 8 weeks after injury [6,7]. In one of the only pediatric studies that examined renal injury of any grade and the risk of long-term hypertension, the authors reported that none of the children were hypertensive at three ⁎ Corresponding author at: Department of Surgery, Division of Urology, School of Medicine, 30 N 1900 E, Salt Lake City, Utah 84132. Tel.: +1 801 581 7304. E-mail address: [email protected] (M.E. Fuchs).
months post-injury [8]. The literature on long-term follow up after renal trauma is very limited because, in general, follow up after trauma is a challenging and outcomes are poorly defined. The purpose of our study was to evaluate a large cohort of highgrade pediatric renal trauma patients and determine the incidence of hypertension. Our secondary aims were to understand if hypertension developed de novo after the renal injuries or was evident at the time of injury, and if present at the time of injury, whether it would resolve over time or require long-term antihypertensive therapy. 1. Materials and methods 1.1. Study population After Institutional Review Board approval, a retrospective review was performed of all pediatric trauma patients at Primary Children’s Hospital in Salt Lake City, Utah between 2002 and 2012. We included all children age ≤17 years old with American Association for Surgery of Trauma (AAST) grade 3–5 renal injuries. All children had a thorough chart review including trauma hospitalization and follow up visits. Clinical variables reviewed and reported in this study include: age, sex, mechanism of injury, injury severity score (ISS), renal trauma grade, hospital length of stay, intensive care unit length of stay, the
http://dx.doi.org/10.1016/j.jpedsurg.2015.05.014 0022-3468/© 2015 Elsevier Inc. All rights reserved.
Please cite this article as: Fuchs ME, et al, The incidence of long-term hypertension in children after high-grade renal trauma, J Pediatr Surg (2015), http://dx.doi.org/10.1016/j.jpedsurg.2015.05.014
2
M.E. Fuchs et al. / Journal of Pediatric Surgery xxx (2015) xxx–xxx
number and types of intervention, the presence of hypertension during the acute trauma hospitalization and at long-term follow up (defined below). 1.2. Patient follow up All patients who met inclusion criteria were sent an IRB approved letter informing them of the study and requesting consent for direct telephone contact. The parents of the children were then contacted by phone, and verbal consent was obtained for this study. The patient’s pediatrician’s office was then contacted, and they provided the most recent blood pressure from a well-child visit. Measurement from a well child visit was chosen in order to help control for blood pressure variation due to acute illness or pain. 1.3. Hypertension definition Any child who was persistently hypertensive and required antihypertensive medication while in the hospital or on discharge was identified as hypertensive. Prior to diagnosing the patient with hypertension the patient’s pain had to be controlled. All trauma patients with renal injuries at Primary Children’s Hospital were instructed to follow up regularly with their pediatricians to have their blood pressure checked. Follow up blood pressures were evaluated by patient age and gender, and a child was considered hypertensive if either the systolic or diastolic pressure was greater than the 90th percentile for age and gender. 1.4. Theory/calculation Simple descriptive analyses were performed to characterize the population using Stata (V12). The incidence of hypertension was calculated for our cohort of patients with long-term follow up hypertension data. 2. Results A total of 62 children were identified with AAST grade 3–5 renal injuries during our study period. There were 36 (58%) males, and the average age for the cohort was 10.2 years at the time of trauma. The median injury severity score was 18.7 (IQR 10–25). Of these 62 injuries, 21 were grade three, 40 were grade four, and only one was grade five (Table 1). Eight patients with grade 4 renal injuries required surgical intervention for urinary extravasation, and none of the patients required nephrectomy, blood transfusion, or other intervention for hemorrhage. Four children (6.5%) were identified to have some degree of hypertension while hospitalized after trauma. None of these children underwent an operative intervention. Table 2 summarizes the clinical course of these hypertensive patients. All four children (6.5%) required one anti-hypertensive medication at the time of discharge. Only one child required dual anti-hypertensive therapy while in the hospital, and the most common medications used were lisinopril, amlodipine, and losartan. The remaining 58 (93.5%) children were normotensive throughout their hospitalization and at the time of discharge. Long-term follow up and recent blood pressure measurements were obtained in 36 (58%) of the patients, including all four hypertensive
Table 1 Severe renal trauma patient characteristics. AAST Renal Injury Grade
Number (%)
3 4 5
21 (34%) 10.6 40 (65%) 9.5 1 (1%) 2.3
a
Age Sex (mean) (% Male)
Average LOS (Days)
11 (52%) 6 24 (60%) 7.7 1 (100%) 17
7 stents, 1 percutaneous nephrostomy tube.
ISS Operative (Mean) Intervention 15 20.2 27
0 8a 0
children. The median follow up was 4.1 years (IQR 2.1-5.1 years) after trauma. None of the children with normal blood pressures during the initial hospitalization subsequently developed hypertension or required anti-hypertensive medications at follow up. There were no pre-existing medical renal diseases identified in our study’s hypertensive children. Only one of the five hypertensive children identified was obese, BMI 33 at time of presentation. This child had discontinued lisinopril at the time of follow-up, which argues against pre-existing medical renal hypertension associated with obesity. Two (3.2%) children remained on anti-hypertensive medication at the time of follow up. These two children did have high injury severity scores. One child, with a score of 29 did not require surgery during his hospitalization, and sustained the following injuries: splenic laceration, rib fractures, pulmonary contusion with pneumohemothorax, humerus and pelvic fractures. The other child, had an ISS of 50, did not require surgery, and sustained: a pulmonary contusion with pneumohemothorax, lumbar and thoracic vertebral fracture, and an injury to the pancreas. Univariate analysis was attempted to identify predictive clinical factors for the development of hypertension following pediatric renal trauma. There were no significant factors that were associated with development of hypertension in the 4 patients, including: age, sex, grade, mechanism of injury, or operative intervention. 3. Discussion The incidence of pediatric hypertension after severe renal trauma in our population was 6.5%. This is the first pediatric study reporting the incidence of intra-hospital and long-term hypertension following severe blunt renal trauma. Two out of 36 patients with long-term blood pressure follow up required long-term anti-hypertensive medication. The only prior study to examine functional outcomes in children following renal trauma used 15 patients with grade 3 or higher injury, and reported zero cases of hypertension at three months and one-year follow-up [8,9]. The mechanism for hypertension after trauma is not well understood, but many have suggested that it is a result of up-regulation of the renin angiotensin system [4,5]. In both children and adults, between 82% and 95% of renal injuries are caused by blunt trauma in the United States [2,4]. The presence of preexisting hypertension in adult renal trauma patients is a potential confounder, making it difficult to accurately identify patients with hypertension directly related to the traumatic event. In one study where 9 of 31 patients experienced post-trauma hypertension 80% had a positive family history of arterial hypertension [10]. In contrast, pediatric populations generally do not have pre-existing hypertension, which allows for a potentially more accurate depiction of the association between renal trauma and hypertension. Traditionally high-grade injuries are classified as grade 4 or 5. We chose to include grade 3 injuries in our definition of high grade because two of the patients that sustained kidney injuries severe enough to develop hypertension were classified as grade 3. The children in our study who developed hypertension were identified during their initial trauma hospitalization, and no additional children had elevated blood pressures at follow-up. This finding suggests that if hypertension is going to present after pediatric renal trauma, then it is more likely to occur in an acute fashion. Worldwide there is not a consensus for post-traumatic blood pressure monitoring; for instance, The European Urologic Association recommends monitoring for renovascular hypertension for at least a year following injury [11]. An inherent shortcoming of population-based research in trauma is the lack of follow-up data. A major strength of this study is the longterm follow-up we acquired by contacting both patients and their pediatricians. With a median follow-up of over four years we would argue that if hypertension was going to develop after traumatic renal injury it would have occurred by this time. The lengthy follow up also provided ample time to demonstrate that half of the hypertensive
Please cite this article as: Fuchs ME, et al, The incidence of long-term hypertension in children after high-grade renal trauma, J Pediatr Surg (2015), http://dx.doi.org/10.1016/j.jpedsurg.2015.05.014
M.E. Fuchs et al. / Journal of Pediatric Surgery xxx (2015) xxx–xxx
3
Table 2 Hypertensive patient summary. Patient Age (yrs)
Sex Mechanism of Injury
AAST Grade
Length of Stay (Days)
ISS Devascularization Injury Present
Anti-HTN at Discharge
Time to Follow-up (yrs)
Anti-HTN at Follow-up
1 2 3 4
M M M F
3 5 4 4
35 17 23 17
29 27 50 16
Lisinopril Amlodipine Lisinopril Lisinopril
4 4.58 4.25 0.25
Lisinopril No Lisinopril No
3.4 2.8 13.5 5.9
Pedestrian vs Auto Fall From Height Fall From Height Motor Vehicle Collision
No Yes No No
patients had their blood pressure normalize by the time of follow up. This suggests that the hypertension following the injury, likely mediated by the renin angiotensinogen system up-regulation, can be temporary as evidenced by 50% resolution in our series. One shortcoming of this study is that we do not have functional outcomes at the same time as long-term blood pressure data. There is one pediatric study that showed at one year follow-up after renal injury, grade 4 and 5 injuries showed 42% and 32% differential function respectively on DMSA scan. Another limitation is that while the current study is the largest cohort of high-grade pediatric renal injury with long-term blood pressure measurements, the study size did not allow us to calculate predictive factors for developing hypertension. Also, our study is subject to recall bias due to the phone interview with parents regarding duration, compliance, and use of hypertensive medication. We do not have pre-trauma data regarding the presence of pre-existing hypertension. This is a potential confounder, but much less of a factor in the pediatric population compared to adult trauma. We chose to use the last well child blood pressure measurement because many of the trauma patients receive their primary care outside of our tertiary medical center, and therefore we do not have access to every blood pressure recorded after a child’s injury. Interestingly, there does not seem to be a relationship between degree of injury and risk of hypertension. While our numbers are quite small, one would assume that the higher risk injuries pose a higher risk of hypertension requiring medication, but the only grade 5 injury in our series, only required anti-hypertensive therapy for a temporary period of time. In addition, 1 patient with a grade 3 injury (a relatively low risk injury) still developed hypertension after injury.
4. Conclusions The risk of hypertension after high-grade pediatric renal trauma is real. However, the risk of any degree of hypertension is low at 6.5%, and the risk of long-term hypertension is only 3.5%. Our study also suggests that there is no apparent risk of de novo hypertension after renal trauma if there is no hypertension present during the acute injury period. References [1] Santucci RA, Wessells H, Bartsch G, et al. Evaluation and management of renal injuries: consensus statement of the renal trauma subcommittee. BJU Int, vol. 93. Blackwell Science Ltd; 2004 937–54. [2] McGeady JB, Breyer BN. Current epidemiology of genitourinary trauma. Urol Clin North Am 2013;40:323–34. [3] Brown SL, Elder JS, Spirnak JP. Are pediatric patients more susceptible to major renal injury from blunt trauma? A comparative study. J Urol 1998;160:138–40. [4] Grimsby GM, Voelzke B, Hotaling J, et al. Pediatric urology demographics of pediatric renal trauma. J Urol 2014;192:1498–502. [5] Delarue A, Merrot T, Fahkro A, et al. Major renal injuries in children: the real incidence of kidney loss. J Pediatr Surg 2002;37:1446–50. [6] Knudson MM, Harrison PB, Hoyt DB, et al. Outcome after major renovascular injuries: a Western trauma association multicenter report. J Trauma Inj Inf Crit Care 2000;49:1116–22. [7] Montgomery RC, Richardson JD, Harty JI. Posttraumatic renovascular hypertension after occult renal injury. Trauma Inj Inf Crit Care 1998;45:106–10. [8] Keller MS, Eric Coln C, Garza JJ, et al. Functional outcome of nonoperatively managed renal injuries in children. Trauma Inj Inf Crit Care 2004;57:108–10. [9] Keller MS, Green MC. Comparison of short- and long-term functional outcome of nonoperatively managed renal injuries in children. J Pediatr Surg 2009;44:144–7. [10] Pereira Júnior GA, Muglia VF, Santos Dos AC, et al. Late evaluation of the relationship between morphological and functional renal changes and hypertension after nonoperative treatment of high-grade renal injuries. World J Emerg Surg 2012;7:26. [11] Lynch TH, Martínez-Piñeiro L, Plas E, et al. EAU guidelines on urological trauma. Eur Urol 2005;47:1–15.
Please cite this article as: Fuchs ME, et al, The incidence of long-term hypertension in children after high-grade renal trauma, J Pediatr Surg (2015), http://dx.doi.org/10.1016/j.jpedsurg.2015.05.014