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Urolithiasis in a Child: An Uncommon Presentation of an Uncommon Disease
CASE REPORT
IT
U r o l i t h i a s i s in a Child: An U n c o m m o n Presentation of an U n c o m m o n Disease
From the Division of Emergency Medicine, Department of Surgery, University of Florida Health Science Center,Jacksonville.
Byron Thompson, MD Ann L Harwood-Nuss, MD, FACEP
Receivedfor publication October 31, 1994. Acceptedfor publication November 14, I994. Copyright © by the American College of Emergency Physicians.
Urolithiasis in children is uncommon. We present the case of a 10-year-old boy with anuria resulting from an obstructing stone in the urethral meatus. There are no previously reported cases of pediatric urolithiasis presenting with anuria. We review . urolithiasis in children, including predisposing factors, clinical features, stone composition, and natural history. The diagnosis may be confusing in younger children but should be considered with complaints of flank or abdominal pain, hematuria, and urinary tract infection. ]Thompson B, Harwood-Nuss AL: Urolithiasis in a child: An uncommon presentation of an uncommon disease. Ann Emerg MedJune 1995;25:837-840.]
INTRODUCT ON Urolithiasis is uncommon in children. Important differences in the clinical presentation exist between adults and children, with age-related variations most prominent in younger children. In addition, it is significantly more common for children to have predisposing factors to stone formation than adults. We describe the case of a child with complete cessation of urinary flow due to a n obstructing calculus of the urethral meatus.
CASE REPORT A 10-year-old boy presented, to the emergency department complaining of inability to urinate for 24 hours. He noted a hard mass obstructing his urethral meatus. During the week before his presentation, the patient experienced mild, intermittent dysuria; the evening before his ED visit, a small amount of gross hematuria was passed. He denied fever and abdominal, flank, or testicular pain. There was no history of trauma, sexual activity, foreign body insertion, special diet, illicit drug use, or medications. The family history was negative for nephrolithiasis. Physical examination revealed a well-developed child in moderate distress. Vital signs were blood pressure, 114/68
JUNE 1995
25:6
ANNALS OF EMERGENCY MEDICINE
83 7
UROLITHIASIS Thompson6, Harwood-Nuss
mm Hg; pulse, T8; respirations, 18; and oral temperature, 37. I°C. The lower abdomen was moderately distended, with a tender, palpable bladder. Bowel sounds were normal, and there was no guarding, rebound tenderness, or costovertebral angle tenderness. Genital examination showed a firm, yellow mass extruding from the urethral meatus (Figure 1). Examination of the testes and rectum was unremarkable. The remainder of the physical examination was normal. Laboratory tests done on admission showed a WBC count of 9,000 mm3; hemoglobin, 11.8 g/dL; and hematocrit, 33%. Sodium was 138 mEq/L; potassium, 3.6 mE@; chloride, 108 mE@; bicarbonate, 22 mEq/L; blood urea nitrogen, 17 mg/dL; and creatinine, 0.9 mg/dL. The serum calcium was 9.9 mg/dL, and the uric acid was 2.0 mg/dL, (normal, 2.3 to 7.5 mg/dL). Urologic consultation was obtained. Urethral meatotomy with manual stone extraction was performed under local anesthesia in the ED. After extraction, a spontaneously voided urine specimen showed 34 RBCs/high-power field; 0 WBCs/high-power field; pH, 6.0; specific gravity, 1.023; and a dipstick that was negative for glucose, protein, bilirubin, ketone, and nitrite. The stone was irregularly shaped and measured 7 mm at its greatest diameter (Figure 2). An IV pyelogram was performed after the stone extraction (Figure 3). A mild, right-sided hydroureteronephrosis suggested that the stone originated in the right kidney.
The patient was given broad-spectrum antibiotics, admitted for observation, and discharged in good condition the following morning. His urine culture showed no growth at 72 hours. Crystallographic analysis of the stone demonstrated the following components: calcium oxalate monohydrate, 50%; calcium oxalate dihydrate, 35%; calcium phosphate, 13%; and protein, 2%.
Figure 1. Calculus extrudingfrom the urethral meatus.
Figure 2. Calculus (diameter, 7 ram).
838
DISCUSSION
Nephrolithiasis in children is uncommon, although there are several published reports in the literature.l-s It is estimated that about 5 to 10 cases of urolithiasis in children are seen at large, US pediatric referral centers each year. 3,6 Urolithiasis is seen with greater frequency in children living in the southeastern United States, in association with metabolic disorders such as idiopathic hypercalciuria, with congenital urinary tract malformations, and in children with prolonged immobilization, r In industrialized nations, the age distribution ranges from 10 months to 16 years6, with the mean age varying widely (10 to 11 years3,6 in the United States and 5 to 7 years5 in England). Boys have a slight predominance in most series. As in adults with urolithiasis, most calculi in children are believed to originate in the kidney, and most are single. 3,6 Bladder stones are reported more frequently in nonindustrialized nations 2, whereas stones appear to be
ANNALS OF EMERGENCY MEDICINE
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UROLITHIASIS
Thompson & Harwood-Nuss
predominantly renal in origin in industrialized nations. Stone composition is also significantly different. It is postulated that some differences are a reflection of dietary variations, although there may be other contributing factors. 9,1° There also appear to be significant differences among industrialized nations regarding mean age of onset, male:female ratios, and predisposing factors. One study suggested that the early evaluation, prompt treatment, and careful follow-up of urinary tract infections and developmental urologic abnormalities in infancy and childhood in the United States might explain the low incidence of stones in younger children in this country. 6 As with many diseases in children, the initial clinical features vary with age. Urinary stone disease presents most often with abdominal or flank pain (47%), followed by gross or microscopic hematuria (33%), and infection (11%).3,6 The incidence of flank and abdominal pain increases from 20% in children less than 5 years old to almost 70% in children 12 to 16 years old. 3 In one series, almost half of the children less than 6 years old had urinary tract infection 6 or incidental radiographic findings of stones (or both) as the presenting feature of their urolithiasis. 3,6
There are minor differences in stone composition among the reported cases of children in the United States, with most series reflecting similar stone composition to that seen in adults. In adults, the distribution of various stone types by the primary component includes calcium oxalate (72%), struvite-magnesium ammonium phosphate (16%), uric acid (6%), and cystine (1%). 11 Most children have stones composed of calcium oxalate (26% to 45%) and calcium phosphate (23%), with struvite stones (17% to 19%), uric acid stones (1% to 8%), and cystine stones (2% to 8%) seen less often. 3 The incidence of stones of infection (struvite) decreases from 37% to 43% in younger children to only 15% in adolescents. 6 In the United States, predisposing factors for stone formation are found in 70% to 80% of children, with the cause of the remaining 25% unknown or idiopathic. 3 Although these factors are usually grouped into four main categories (urinary tract infection 7,1°, anatomic abnormalities, metabolic abnormalities, and idiopathic), reports vary widely in the incidence and distribution. Also, more than one predisposing factor commonly exists in a given patient. For example, patients with congenital abnormalities often have coexistent infection of the urine and struvite stones. Metabolic abnormalities or conditions that predispose to metabolic abnormalities (eg, immobilization and corticosteroids) are identified in 36% to 50% of children with urofithiasis. 3,6 Most metabolic stones are due to
JUNE 1995
25:6
ANNALS OF EMERGENCY MEDICINE
hypercalcinria and hyperoxaluria, leading to the formation of calcium salt stones. Hypercalcinria is most often due to diet, furosemide therapy, prednisone therapy, and distal renal tubular acidosis. 7,~° Other metabolic abnormalities include hyperuricosuria and cystinuria, producing uric acid and cystine stones, respectively. Genitourinary anomalies are often found and include obstructive lesions (obstruction of the ureteropelvic junction, hydronephrosis, and urethral stricture), stasis (vesicoureteral reflux and neurogenic bladder), urine diversion, and other assorted anomalies. 3,6-s,l° Urinary tract infection is identified in approximately 47% of children with stones; however, nearly all infections are associated with secondary conditions (most often prior urinary tract surgery).6 The natural history of urolithiasis in children is variable. In adults, recurrence of stones is the rule. In children, the recurrence rate of stones ranges widely from 3.8% to 67% 3,5-r and appears to be highest in children with metabolic abnormalities. Most series report that the majority of stones in children will not pass spontaneously but require some form of inLervention (extracorporeal shock-wave lithotripsy, surgery, or cystoscopy with basket extraction). 3,12 Our patient differed in several respects from the usual features of pediatric urolithiasis, including mode of pre-
Figure 3,
IV pyelogram after stone extraction, demonstrating right-sided hydroureteronephrosis.
839
UROLITHIASIS
Thompson & Harwood-Nuss
sentation and absence of predisposing factors. Although he complained of mild dysuria and gross hematuria, the most prominent feature was the complete cessation of urinary output for 24 hours prior to his ED visit. There is only one other case report in the medical literature in which the calculus appeared impinged at the urethral meatus. ~3 To the best of our knowledge, there are no previous reports of anuria as the presenting complaint. Our patient's metabolic and urologic evaluation revealed no apparent predisposing factors to stone formation, unlike the majority of US children with urolithiasis. An unusual feature of our case involved our patient's stone size, 7 ram. It is distinctly unusual for a stone of this size in an adult to pass spontaneously from the kidney through the ureters into the bladder; one would presume this to also be unusual in a child with even smaller ureteral dimensions. Finally, we cannot comment on the issue of stone recurrence because insufficient time has elapsed since the patientg presentation and treatment.
11. LingemanJ: Calculousdisease of the kidney and bladder, in Harwood-NussA (ed): The Clinical Practice of EmergencyMedicine, ed 2. Philadelphia,JB Lippincott (in press). 12. eI-DamanhouryH, Burger B, Hohenfellner R: Surgical aspects of urolithiasis in children. Pediatr Nephro11991;5:339-347. 13. Wenzl JE, Burke EC, Stickler GB, et al: Nephrolithiasis and nephmcalcinosis in children. Pediatrics 1968;4I :57-61.
Reprint no. 47/1/64106 Address for Reprints: Ann L Harwood-Nuss, MD, FACEP Division of Emergency Medicine University of Florida Health Science Center 655 West Eighth Street Jacksonville, Florida 32209 904-549-4124 Fax 904-549-4508
SUMMARY
We discuss the case of a child with urolithiasis presenting with anuria. Although urolithiasis in children is uncommon, the emergency physician should consider this disease in the differential diagnosis in all pediatric age groups. The clinical features suggestive of urolithiasis most often include abdominal or flank pain, hematuria, or signs and symptoms of urinary tract infection. In younger children, the clinical features may be less suggestive of urolithiasis and more closely resemble those of urinary tract infection. REFERENCES 1. Dajani AM, Abu KhadreAL, Baghdadi FM: Uralithiasis in Jordanian children. A report ef 52 cases. Br J Uro11988;61:482-486. 2. BasaklarAC, Kale N: Experiencewith childhood urolithiasis. Report of 96 cases. BrJ Urol 1991;67:203-205. 3. Milliner DS, Murphy ME: UroIithiasis in pediatric patients. Mayo Clin Prec 1993;68:241-248. 4. Androulakekis PA, Michael V, PolychronopoulouS, et al: Paediatric urolithiasis in Greece.BrJ Urel 1991;67:206-209. 5. Diamond DA: Clinical patterns of paediatric urolithiasis. BrJLIre11991;68:195-198 6. GearhartJP, Herzberg6Z, Jeffs RD: Childhood urolithiasis: Experiencesand advances. Pediatrics 1991;87:445-450. 7. PolinskyMS, Kaiser BA, Baluarte HJ: Urolithiasis in childhood. Pedietr Clin North Am 1987;34:683-71O. 8. Nimkin K, Lebowitz RL, Share JC, et al: Urolithiasis in a children's hospital: 1985-1990. Urol Radie11992;14:139-143. 9. Shah AM, KalmunkerS, PunekarSV, et al: Spectrum of pediatric urolithiasis in western India. Indian J Pediatr 1991;58:543-549. 10. Lieberman E: Importanceof metabolic contributions to urolithiasis in pediatric patients (editorial). Mayo Clin Prec1993;68:313-315.
840
ANNALS OF EMERGENCY MEDICINE
25:6
JUNE 1995
IT
U r o l i t h i a s i s in a Child: An U n c o m m o n Presentation of an U n c o m m o n Disease
From the Division of Emergency Medicine, Department of Surgery, University of Florida Health Science Center,Jacksonville.
Byron Thompson, MD Ann L Harwood-Nuss, MD, FACEP
Receivedfor publication October 31, 1994. Acceptedfor publication November 14, I994. Copyright © by the American College of Emergency Physicians.
Urolithiasis in children is uncommon. We present the case of a 10-year-old boy with anuria resulting from an obstructing stone in the urethral meatus. There are no previously reported cases of pediatric urolithiasis presenting with anuria. We review . urolithiasis in children, including predisposing factors, clinical features, stone composition, and natural history. The diagnosis may be confusing in younger children but should be considered with complaints of flank or abdominal pain, hematuria, and urinary tract infection. ]Thompson B, Harwood-Nuss AL: Urolithiasis in a child: An uncommon presentation of an uncommon disease. Ann Emerg MedJune 1995;25:837-840.]
INTRODUCT ON Urolithiasis is uncommon in children. Important differences in the clinical presentation exist between adults and children, with age-related variations most prominent in younger children. In addition, it is significantly more common for children to have predisposing factors to stone formation than adults. We describe the case of a child with complete cessation of urinary flow due to a n obstructing calculus of the urethral meatus.
CASE REPORT A 10-year-old boy presented, to the emergency department complaining of inability to urinate for 24 hours. He noted a hard mass obstructing his urethral meatus. During the week before his presentation, the patient experienced mild, intermittent dysuria; the evening before his ED visit, a small amount of gross hematuria was passed. He denied fever and abdominal, flank, or testicular pain. There was no history of trauma, sexual activity, foreign body insertion, special diet, illicit drug use, or medications. The family history was negative for nephrolithiasis. Physical examination revealed a well-developed child in moderate distress. Vital signs were blood pressure, 114/68
JUNE 1995
25:6
ANNALS OF EMERGENCY MEDICINE
83 7
UROLITHIASIS Thompson6, Harwood-Nuss
mm Hg; pulse, T8; respirations, 18; and oral temperature, 37. I°C. The lower abdomen was moderately distended, with a tender, palpable bladder. Bowel sounds were normal, and there was no guarding, rebound tenderness, or costovertebral angle tenderness. Genital examination showed a firm, yellow mass extruding from the urethral meatus (Figure 1). Examination of the testes and rectum was unremarkable. The remainder of the physical examination was normal. Laboratory tests done on admission showed a WBC count of 9,000 mm3; hemoglobin, 11.8 g/dL; and hematocrit, 33%. Sodium was 138 mEq/L; potassium, 3.6 mE@; chloride, 108 mE@; bicarbonate, 22 mEq/L; blood urea nitrogen, 17 mg/dL; and creatinine, 0.9 mg/dL. The serum calcium was 9.9 mg/dL, and the uric acid was 2.0 mg/dL, (normal, 2.3 to 7.5 mg/dL). Urologic consultation was obtained. Urethral meatotomy with manual stone extraction was performed under local anesthesia in the ED. After extraction, a spontaneously voided urine specimen showed 34 RBCs/high-power field; 0 WBCs/high-power field; pH, 6.0; specific gravity, 1.023; and a dipstick that was negative for glucose, protein, bilirubin, ketone, and nitrite. The stone was irregularly shaped and measured 7 mm at its greatest diameter (Figure 2). An IV pyelogram was performed after the stone extraction (Figure 3). A mild, right-sided hydroureteronephrosis suggested that the stone originated in the right kidney.
The patient was given broad-spectrum antibiotics, admitted for observation, and discharged in good condition the following morning. His urine culture showed no growth at 72 hours. Crystallographic analysis of the stone demonstrated the following components: calcium oxalate monohydrate, 50%; calcium oxalate dihydrate, 35%; calcium phosphate, 13%; and protein, 2%.
Figure 1. Calculus extrudingfrom the urethral meatus.
Figure 2. Calculus (diameter, 7 ram).
838
DISCUSSION
Nephrolithiasis in children is uncommon, although there are several published reports in the literature.l-s It is estimated that about 5 to 10 cases of urolithiasis in children are seen at large, US pediatric referral centers each year. 3,6 Urolithiasis is seen with greater frequency in children living in the southeastern United States, in association with metabolic disorders such as idiopathic hypercalciuria, with congenital urinary tract malformations, and in children with prolonged immobilization, r In industrialized nations, the age distribution ranges from 10 months to 16 years6, with the mean age varying widely (10 to 11 years3,6 in the United States and 5 to 7 years5 in England). Boys have a slight predominance in most series. As in adults with urolithiasis, most calculi in children are believed to originate in the kidney, and most are single. 3,6 Bladder stones are reported more frequently in nonindustrialized nations 2, whereas stones appear to be
ANNALS OF EMERGENCY MEDICINE
2 5 : 6 JUNE 1995
UROLITHIASIS
Thompson & Harwood-Nuss
predominantly renal in origin in industrialized nations. Stone composition is also significantly different. It is postulated that some differences are a reflection of dietary variations, although there may be other contributing factors. 9,1° There also appear to be significant differences among industrialized nations regarding mean age of onset, male:female ratios, and predisposing factors. One study suggested that the early evaluation, prompt treatment, and careful follow-up of urinary tract infections and developmental urologic abnormalities in infancy and childhood in the United States might explain the low incidence of stones in younger children in this country. 6 As with many diseases in children, the initial clinical features vary with age. Urinary stone disease presents most often with abdominal or flank pain (47%), followed by gross or microscopic hematuria (33%), and infection (11%).3,6 The incidence of flank and abdominal pain increases from 20% in children less than 5 years old to almost 70% in children 12 to 16 years old. 3 In one series, almost half of the children less than 6 years old had urinary tract infection 6 or incidental radiographic findings of stones (or both) as the presenting feature of their urolithiasis. 3,6
There are minor differences in stone composition among the reported cases of children in the United States, with most series reflecting similar stone composition to that seen in adults. In adults, the distribution of various stone types by the primary component includes calcium oxalate (72%), struvite-magnesium ammonium phosphate (16%), uric acid (6%), and cystine (1%). 11 Most children have stones composed of calcium oxalate (26% to 45%) and calcium phosphate (23%), with struvite stones (17% to 19%), uric acid stones (1% to 8%), and cystine stones (2% to 8%) seen less often. 3 The incidence of stones of infection (struvite) decreases from 37% to 43% in younger children to only 15% in adolescents. 6 In the United States, predisposing factors for stone formation are found in 70% to 80% of children, with the cause of the remaining 25% unknown or idiopathic. 3 Although these factors are usually grouped into four main categories (urinary tract infection 7,1°, anatomic abnormalities, metabolic abnormalities, and idiopathic), reports vary widely in the incidence and distribution. Also, more than one predisposing factor commonly exists in a given patient. For example, patients with congenital abnormalities often have coexistent infection of the urine and struvite stones. Metabolic abnormalities or conditions that predispose to metabolic abnormalities (eg, immobilization and corticosteroids) are identified in 36% to 50% of children with urofithiasis. 3,6 Most metabolic stones are due to
JUNE 1995
25:6
ANNALS OF EMERGENCY MEDICINE
hypercalcinria and hyperoxaluria, leading to the formation of calcium salt stones. Hypercalcinria is most often due to diet, furosemide therapy, prednisone therapy, and distal renal tubular acidosis. 7,~° Other metabolic abnormalities include hyperuricosuria and cystinuria, producing uric acid and cystine stones, respectively. Genitourinary anomalies are often found and include obstructive lesions (obstruction of the ureteropelvic junction, hydronephrosis, and urethral stricture), stasis (vesicoureteral reflux and neurogenic bladder), urine diversion, and other assorted anomalies. 3,6-s,l° Urinary tract infection is identified in approximately 47% of children with stones; however, nearly all infections are associated with secondary conditions (most often prior urinary tract surgery).6 The natural history of urolithiasis in children is variable. In adults, recurrence of stones is the rule. In children, the recurrence rate of stones ranges widely from 3.8% to 67% 3,5-r and appears to be highest in children with metabolic abnormalities. Most series report that the majority of stones in children will not pass spontaneously but require some form of inLervention (extracorporeal shock-wave lithotripsy, surgery, or cystoscopy with basket extraction). 3,12 Our patient differed in several respects from the usual features of pediatric urolithiasis, including mode of pre-
Figure 3,
IV pyelogram after stone extraction, demonstrating right-sided hydroureteronephrosis.
839
UROLITHIASIS
Thompson & Harwood-Nuss
sentation and absence of predisposing factors. Although he complained of mild dysuria and gross hematuria, the most prominent feature was the complete cessation of urinary output for 24 hours prior to his ED visit. There is only one other case report in the medical literature in which the calculus appeared impinged at the urethral meatus. ~3 To the best of our knowledge, there are no previous reports of anuria as the presenting complaint. Our patient's metabolic and urologic evaluation revealed no apparent predisposing factors to stone formation, unlike the majority of US children with urolithiasis. An unusual feature of our case involved our patient's stone size, 7 ram. It is distinctly unusual for a stone of this size in an adult to pass spontaneously from the kidney through the ureters into the bladder; one would presume this to also be unusual in a child with even smaller ureteral dimensions. Finally, we cannot comment on the issue of stone recurrence because insufficient time has elapsed since the patientg presentation and treatment.
11. LingemanJ: Calculousdisease of the kidney and bladder, in Harwood-NussA (ed): The Clinical Practice of EmergencyMedicine, ed 2. Philadelphia,JB Lippincott (in press). 12. eI-DamanhouryH, Burger B, Hohenfellner R: Surgical aspects of urolithiasis in children. Pediatr Nephro11991;5:339-347. 13. Wenzl JE, Burke EC, Stickler GB, et al: Nephrolithiasis and nephmcalcinosis in children. Pediatrics 1968;4I :57-61.
Reprint no. 47/1/64106 Address for Reprints: Ann L Harwood-Nuss, MD, FACEP Division of Emergency Medicine University of Florida Health Science Center 655 West Eighth Street Jacksonville, Florida 32209 904-549-4124 Fax 904-549-4508
SUMMARY
We discuss the case of a child with urolithiasis presenting with anuria. Although urolithiasis in children is uncommon, the emergency physician should consider this disease in the differential diagnosis in all pediatric age groups. The clinical features suggestive of urolithiasis most often include abdominal or flank pain, hematuria, or signs and symptoms of urinary tract infection. In younger children, the clinical features may be less suggestive of urolithiasis and more closely resemble those of urinary tract infection. REFERENCES 1. Dajani AM, Abu KhadreAL, Baghdadi FM: Uralithiasis in Jordanian children. A report ef 52 cases. Br J Uro11988;61:482-486. 2. BasaklarAC, Kale N: Experiencewith childhood urolithiasis. Report of 96 cases. BrJ Urol 1991;67:203-205. 3. Milliner DS, Murphy ME: UroIithiasis in pediatric patients. Mayo Clin Prec 1993;68:241-248. 4. Androulakekis PA, Michael V, PolychronopoulouS, et al: Paediatric urolithiasis in Greece.BrJ Urel 1991;67:206-209. 5. Diamond DA: Clinical patterns of paediatric urolithiasis. BrJLIre11991;68:195-198 6. GearhartJP, Herzberg6Z, Jeffs RD: Childhood urolithiasis: Experiencesand advances. Pediatrics 1991;87:445-450. 7. PolinskyMS, Kaiser BA, Baluarte HJ: Urolithiasis in childhood. Pedietr Clin North Am 1987;34:683-71O. 8. Nimkin K, Lebowitz RL, Share JC, et al: Urolithiasis in a children's hospital: 1985-1990. Urol Radie11992;14:139-143. 9. Shah AM, KalmunkerS, PunekarSV, et al: Spectrum of pediatric urolithiasis in western India. Indian J Pediatr 1991;58:543-549. 10. Lieberman E: Importanceof metabolic contributions to urolithiasis in pediatric patients (editorial). Mayo Clin Prec1993;68:313-315.
840
ANNALS OF EMERGENCY MEDICINE
25:6
JUNE 1995