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Role of Antenatal Diagnosis of Congenital Malformed Kidney in Decreasing Postnatal Kidney Trauma

Dusanka Dobanovacki¹ , Nada Vuckovic² , Andjelka Slavkovic³ , Dragan Sarac¹

¹Institute for Children and Adolescents' Health Care of Vojvodina Novi Sad, Serbia

²Pathology and Histology Centre, Clinical Centre of Vojvodina, Medical School University of Novi Sad, Serbia

³Pediatric Surgery and Orthopaedic Clinic, Nis, Serbia

 

Correspondence:

Nada Vuckovic

Pathology and Histology Centre, Clinical Centre of Vojvodina

Medical Faculty, University of Novi Sad, Serbia

21000 Novi Sad, Serbia, Hajduk Veljkova 3

E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Phone: +381 21 520388; Fax: +381 21 6624153

 

Abstract

Introduction: To identify the incidence of blunt renal trauma in children and adolescents as related to diagnosed pre-existing asymptomatic congenital kidney abnormalities and compare the incidence of trauma, before and after the introduction of prenatal ultrasound diagnostics of congenital abnormalities in the Province of Vojvodina.

Patients and methods: A retrospective analysis from trauma data base (1975 - 2014) was performed, searching for the total number of patients admitted to hospital for renal trauma and the number affecting a congenital malformed kidney. It was divided into two parts: Group I – the period prior to the introduction of prenatal ultrasound diagnostics of congenital abnormalities (1975 - 1993) and Group II - time period after its introduction (1994 -2014).

Results: One hundred and ninety-three patients with kidney trauma were admitted, 15 (7.7%) of them with various asymptomatic and previously non-detected congenital renal lesions. In the Group I, 76 patients had a traumatic kidney injury; 12 of them (15.7%) with earlier not diagnosed and asymptomatic congenital renal disorders. In the Group II out of 117 renal injuries only in 3 (2.5%) pre-existing kidney congenital lesions were diagnosed.

Conclusion: Antenatal fetal ultrasound examinations successfully decrease the incidental diagnosis of undetected kidneys congenital abnormalities following abdominal trauma.

Keywords: kidney, congenital abnormalities, blunt trauma, antenatal.

 

Introduction

Over the last years trauma incidence among children and adolescents has increased resulting from traffic accidents, falls, kicks or blows during play or while playing sports. Trauma to the urinary tract is second on the list of children injuries just after trauma to the central nervous system [1]. Kidneys are more vulnerable to injury in children than in adults because of a less protected position during childhood: the kidneys are larger than in adults in proportion to the body cavity lying mainly within abdomen, are less protected by ribs, abdominal muscles are not well developed as in adults providing less protection and with a perirenal fatty envelope poorly developed [2,3].

A normally developed kidney is supplied with a protective mechanism against mechanical forces: the elasticity of healthy renal parenchyma and a compensative effect of the capsule if the pressures inside the collecting system and vascular network are normal. It is known that unhealthy tissue suffers changes resulting in decreased or absent elasticity.

Congenital malformed kidneys have different tissue architecture and that is the reason they are more vulnerable to any degree of trauma compared to normal kidneys [3,4]. The incidence of congenital malformed kidneys diagnosed at the time of trauma in series of blunt abdominal trauma is different in medical publications, going up to 23% [5,6].

Patients and methods

We reviewed the medical records of 193 children and adolescents up to 17 years of age, diagnosed with blunt renal trauma between 1975 and 2014. Age, sex, mechanism of injury, urine analysis, imaging studies, type of renal injury, type of congenital renal anomalies, associated extrarenal injuries, treatment and outcome were evaluated for each patient. Classification and degree of injury were determined retrospectively, according to the organ injury scale by the RIAAST Grading System (Renal Injuries American Association for Surgery of Trauma Organ Injury Scale, Score for Kidney) [7,8,9].

Among the patients with blunt renal trauma, a group of patients with silent congenital anomalies was recorded. The analyzed time period (40 years) was divided into two subperiods and the patients were grouped accordingly into two groups. Group I included patients who were injured between 1975 and 1993, which was the time period before the introduction of ultrasonography as a method for antenatal diagnostic of congenital anomalies into our practice and in the Vojvodina Province in general. Group II included patients that had been injured over the 1994 – 2014 time period, when systematic ultrasonographic fetal examinations were provided.

Having been informed that the congenital deteriorated kidney of their children were more vulnerable to minor trauma, the parents were advised about their child’s play and how to choose a sport. Combat and contact sports were not recommended in those children. The medical data were analyzed and T-tests were used to analyze the differences between group I and II. For data analysis, Microsoft Office Excel 2010 was used.

Results

A total number of 193 patients admitted for solitary or concomitant blunt renal injuries were registered over the 1975 - 2014 time period. The patients were between 3 and 17 years of age. Number of patients, mean age, male to female ratio, cause of injuries, and incidence of associated injuries are presented in Table I. During diagnostic tests, congenital abnormalities of the injured kidneys were noticed in 15 (7.7%) patients among 193 patients. In all cases the lesion was asymptomatic and neither the parents not the patients had been aware of it before admission.

Clinical presentation in patients with congenital malformed kidneys were hematuria (n=15) and ipsilateral lumbar pain (n=13). The leading sign in all patients was macroscopic hematuria. It appeared immediately after trauma or a few hours later.

Table I: Kidney injury data 1975 - 2014

No of patients

Age (mean)

   M:F ratio

              Cause of trauma                                                                                                  Bicycle           Traffic           Fall              Sport             Fight                Minor trauma

Associated

injury

Healthy Kidney

178

3-17 (8.7)

123:55

(69.1%:30.8%)

99

55.6%

59

33.1%

14

7.8%

5

2.8%

1

0.5%

--

109

61.2%

Abnormal Kidney

15

3-17 (10.1)

14:1

(93.3%:6.6%)

2

13.3%

2

13.3%

2

13.3%

1

6.6%

--

8

53.3%

2

13.3%

Total

193

3-17 (9.4)

137:56

(70.9%: 9.0%)

111

(57.5%)

After ultrasonography and laboratory investigations eleven patients underwent intravenous urography, being the only available procedure at that time. CT scan with contrast was necessary in three patients because concomitant injuries of abdominal and thoracic organs were suspected. One patient was referred to our hospital with MRI performed elsewhere. Unilateral congenital malformed kidney was detected in 10 (66.6%) patients. Bilateral congenital anomalies, were observed in 3 patients (20.0%). Two children had solitary kidney (13.3%). The list of found abnormalities is presented in Table 2.

N

Cong. anomaly

Side

Age

Gender

Place and cause of trauma

AAST grade*

Treatment

Follow-up

1

Arcuate kidney

R

11

M

Street-fall off a bicycle

2 contusion

bed and rest

lost

2

Multicystic kidney

L

10

M

Playground-minor back trauma

1 contusion

bed and rest

lost

3

Hydronephrosis

R

9

M

Playground-minor  trauma

4 pelvis rupture

pyeloplasty

satisfied

4

Hydronephrosis

R

8

M

Playground-minor  trauma

4 pelvis rupture

pyeloplasty

satisfied

5

Hydronephrosis

(Afunction L)

R

10

M

Traffic accident

(consequence of trauma?)

4 pelvis rupture

calicoureteroanastomosis

lost

6

Hydronephrosis

L

9

M

Street-fall off a bicycle

4 pelvis rupture

pyeloplasty

satisfied

7

Solitary kidney

R

10

M

School-minor trauma

1 contusion

bed and rest

hypertension

8

Solitary cyst

L

12

M

Playground-minor  trauma

1 contusion

bed and rest

normal

9

Hydronephrosis

(Afunction L)

R

3

F

House-fall from height

(consequence of trauma?)

4 pelvis rupture

pyeloplasty

lost

10

Hydronephrosis

L

7

M

Playground-minor  trauma

4 pelvis rupture

pyeloplasty

satisfied

11

Hydronephrosis

R

9

M

Playground-fall

4 pelvis rupture

pyeloplasty

satisfied

12

Hydronephrosis

L

8

M

Minor trauma

4 pelvis rupture

pyeloplasty

satisfied

13

Hydronephrosis

L

17

M

Traffic accident

5 scattered kidney    

nephrectomy

lost

14

Solitary kidney

L

17

M

Sport-fall

1 contusion

bed and rest

hypertension

15

Bilateral cystic kidney

L

12

M

Minor trauma

4 rupture lower pole

bed and rest

satisfied

                         *Renal Injury Grading System of the American Association for the Surgery of Trauma [8]

Nonoperative treatment («bed and rest») was performed in 6 (40.0%) patients, the operative in 9 patients (60.0%). No early complications were observed. Hypertension was recorded in 2 patients with solitary kidneys before the age of 18 but successfully treated with antihypertensive medication. The type of malformation, mode of trauma and therapy are listed in Table 2. Five patients (33.3%) were lost over the long term follow up.

The overall analyzed time-period was divided into two sub-periods - ultrasonography was not performed in the first period because it was not included into the standard examination of a pregnant woman at that time. Group I consisted of patients evaluated for renal trauma over the 1975 -1993 period, when the total number of blunt renal injuries was 76 and incidental diagnosis of congenital abnormalities following renal trauma 12 (15.7%). All the anomalies were previously asymptomatic and undetected. Group II covered the time period 1994 – 2014, with noninvasive ultrasonographic prenatal screening. In that period 117 patients sustained renal trauma and only in 3 (2.5%) pre-existing congenital abnormalities were detected after birth. All those three patients were born outside of the Province of Vojvodina and had not been covered by prenatal screening ultrasound.

Statistical analysis using Student's t-test showed significant difference between Group I and Group II with p<0.01 (Microsoft Excel program 2010).

Discussion

Insufficient physical protective mechanisms of the kidneys in children could be a risk factor that predisposes for renal injury. Pre-existing congenital abnormalities have been found 3 - 5 times more common in pediatric patients after trauma than in adults [1,2,10]. The incidence of prior non recognized congenital renal abnormalities diagnosed after blunt renal trauma in literature goes up to 23% [3,5]. In our study, over the whole 1975 -2014 time period the incidence was 7.7%.

General literature data about kidney trauma estimated that boys suffer renal injury more often than girls. The most recorded age group is 8-10 years old boys (72.6% [11] up to 93.8% [3]). Our patients were 3 to 17 years old, with mean age between 8 and 10 (10/15; 66.6%). Male to female ratio was 14:1. According to reports in literature, non significant trauma was the main cause of injury in patients having congenital malformed kidney, as it was in our study in 8 patients (53.3%). All 15 patients revealed macrohematuria immediately or a few hours after the trauma, with ipsilateral lumbar pain in 13 patients.

Injury of malformed kidneys with history of lower velocity accidents has a higher incidence of monotrauma. Multiorgan injuries are present as a rule associated with blunt renal injuries, ranging from 44% [5] up to 77.6% [3]; however, we recorded them only in two patients (13.3%) who had been involved in traffic injuries. After the imaging examinations the most common renal anomalies observed in literature susceptible to blunt injury are hydronephrosis (38%), and ectopic kidney (7%). Our list of abnormalities is presented in Table II. In our series the most frequent was hydronephrosis (9/15).

In 3 children (20%) congenital anomalies were found in both kidneys, injured and non-injured. In 2 patients bilateral hydronephrosis was present and incidentally revealed. CT scan showed an injury of hydronephrotic kidney on one side and nonfunctional kidney on the other side where middle hydronephrosis were noticed. Since they both were admitted to hospital 10 and 12 hours after trauma, the arteriograms in searching for artery injuries were not performed because it was already late for surgical exploration and saving of the kidney [3,10,14]. However, some authors state that nonvisualization of the kidney on IVP does not necessarily correlate with arterial occlusion or injury; other factors like renal contusion with spasm, overhydration and hypotension or hypoperfusion may produce similar findings [15]. After all, the question is still unanswered if the kidneys were nonfunctional due to hydronephrosis or as a consequence of traumatic renal vascular damages, since both patients were lost to follow up. The third patient had bilateral cystic lesions and rupture of the lower pole on the left where the largest cyst was settled.

In our series 2 solitary kidneys were found and vulnerability to minor trauma was attributed to compensatory hypertrophy. It is agreed in literature that expectative manner and nonoperative approach are primary after a blunt abdominal or renal trauma. Minor contusions can be conservatively treated: bed rest, close monitoring of vital signs, urine output, serial hemoglobin/hematocrit examinations, and serial abdominal imaging examinations [1,3], for 7 to 10 days until pain and hematuria clear. Antibiotic protection is necessary until hematuria resolved and ultrasound finding disappear [11,12,16]. Repeated ultrasound imaging or CT of the kidney 2 - 3 days following the trauma was recommended in patients with grade 3,4, and 5 renal injuries [17] and all these guidelines suggested by many authors were applied in our practice. If the extravasation of contrast urine has resulted from pelvic rupture, surgical approach is a method of choice: pyeloplasty or other kind of pelviureteric anastomosis could be performed [18]. In our study 60.0% patients underwent the operative therapy. It is higher than reported in literature [11,16,18] because we recorded more pelvic rupture of hydronephrotic kidneys (n=9) and the operative treatment was indicated. If the injured kidney is with very reduced parenchyma and scattered (Type 5), nephrectomy with vital monitoring and blood substitution is advisable, which was performed in one of our patients.

In several reported series of child renal trauma, 87% to 98% were successfully managed without operation. Multiple studies have found that the nephrectomy rate in patients with traumatic renal injuries was higher with surgical exploration than with non-operative management [19] so we adopted conservative management whenever it was possible.

From a trauma data base for almost 15,000 children, McAleer and colleagues [3] found 16 patients with renal injuries in congenital malformed kidneys - only six required surgery. Nephrectomy should be considered in irreparable grade 4 - 5 renal injuries and in hemodynamically unstable patients with multiorgan trauma [10].

High-grade severe injuries are most likely to develop further problems and include delayed hemorrhage, urinoma, hypertension, hydronephrosis, calculi, pseudoaneurysms, renal scars, and loss of renal function. That is the reason why patients with congenital abnormalities of kidney who have suffered the trauma should undergo testing of the renal function and morphology once a year [20].

Conclusion

Prenatal ultrasonographic examination is a great advance in early screening for renal congenital abnormalities. This diagnostic modality is a part of obstetric algorithm in almost all pregnant women control in the Province of Vojvodina. This is an opportunity not only to help the children by providing an early diagnoses and therapy, but to decrease the trauma incidental finding of congenital abnomalities, and also to prevent the injury of such deteriorated kidneys.

 

 

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