Casus 'Belly'
Answer: B
This toddler presents with a challenging combination of a history of vague symptoms, a frustrated parent, and a relatively well appearance in the ED. Although it is tempting to ascribe his presentation to the ever-prevalent
constipation, anchoring bias could prevent the provider from doing a thorough history and examination.
Wilms tumor (also called nephroblastoma) is the most common pediatric renal tumor, and makes up 6-10% of
all childhood cancer cases. The typical presentation is a child under 5 years of age who has a palpable mass found incidentally on physical examination. If there are symptoms, they tend to be vague: non-specific abdominal pain, loss of appetite, or fever. Children may be fatigued or sleepy due to relative hypoglycemia
caused by higher metabolic rate from increasing tumor burden (coupled with a child’s immature regulatory functions, such as gluconeogenesis). Wilms tumor may present with hematuria and/or hypertension, as in this child’s case (B).
Although a systolic blood pressure of 126 mmHg may not seem high, it certainly is above normal for this two-year-old. Recall that the PALS formula for systolic blood pressure (SBP) for children between 1-10 years of age
[SBP = (age x 2) +70] is for the 5th percentile of SBP (i.e. the threshold between compensated and decompensated shock).
If we think about what should be “normal” for a child of this age (50th percentile) we use this formula:
SBP = (age x 2) + 90. This two-year-old boy’s SBP “normal target average” would be 94 mmHg, not 126 mmHg – a red flag that (although possibly due to many conditions) his presenting blood pressure and this abdominal finding may be related.
Wilms tumor is mostly found in otherwise healthy children; 10% of cases are associated with a syndrome such as WAGR (Wilms tumor, aniridia, genitourinary and mental retardation) syndrome, Beckwith-Wiedemann syndrome (“overgrowth syndrome”: macrosomia, macroglossia, midline abdominal defects, ear pits, and hypoglycemia),
Denys-Drash syndrome (rare; triad of pseudohermaphroditism, renal sclerosis, and Wilms tumor). The key point here is that the congenital kids will likely be followed closely and it is improbable that Wilms in these children will be missed. In the ED, we must look after the otherwise healthy children in whom an incidental finding could affect morbidity and mortality.
The key to diagnosing Wilms tumor is consideration of the diagnosis. In a suspected case, abdominal ultrasound can confirm the mass as cystic versus solid and look for intravascular extension of tumor (especially into the inferior vena cava or renal veins). This ultrasound shows a cystic structure impinging on the normal renal parenchyma:
This toddler presents with a challenging combination of a history of vague symptoms, a frustrated parent, and a relatively well appearance in the ED. Although it is tempting to ascribe his presentation to the ever-prevalent
constipation, anchoring bias could prevent the provider from doing a thorough history and examination.
Wilms tumor (also called nephroblastoma) is the most common pediatric renal tumor, and makes up 6-10% of
all childhood cancer cases. The typical presentation is a child under 5 years of age who has a palpable mass found incidentally on physical examination. If there are symptoms, they tend to be vague: non-specific abdominal pain, loss of appetite, or fever. Children may be fatigued or sleepy due to relative hypoglycemia
caused by higher metabolic rate from increasing tumor burden (coupled with a child’s immature regulatory functions, such as gluconeogenesis). Wilms tumor may present with hematuria and/or hypertension, as in this child’s case (B).
Although a systolic blood pressure of 126 mmHg may not seem high, it certainly is above normal for this two-year-old. Recall that the PALS formula for systolic blood pressure (SBP) for children between 1-10 years of age
[SBP = (age x 2) +70] is for the 5th percentile of SBP (i.e. the threshold between compensated and decompensated shock).
If we think about what should be “normal” for a child of this age (50th percentile) we use this formula:
SBP = (age x 2) + 90. This two-year-old boy’s SBP “normal target average” would be 94 mmHg, not 126 mmHg – a red flag that (although possibly due to many conditions) his presenting blood pressure and this abdominal finding may be related.
Wilms tumor is mostly found in otherwise healthy children; 10% of cases are associated with a syndrome such as WAGR (Wilms tumor, aniridia, genitourinary and mental retardation) syndrome, Beckwith-Wiedemann syndrome (“overgrowth syndrome”: macrosomia, macroglossia, midline abdominal defects, ear pits, and hypoglycemia),
Denys-Drash syndrome (rare; triad of pseudohermaphroditism, renal sclerosis, and Wilms tumor). The key point here is that the congenital kids will likely be followed closely and it is improbable that Wilms in these children will be missed. In the ED, we must look after the otherwise healthy children in whom an incidental finding could affect morbidity and mortality.
The key to diagnosing Wilms tumor is consideration of the diagnosis. In a suspected case, abdominal ultrasound can confirm the mass as cystic versus solid and look for intravascular extension of tumor (especially into the inferior vena cava or renal veins). This ultrasound shows a cystic structure impinging on the normal renal parenchyma:
CT and MRI can characterize the mass and possible metastasis better; importantly the contralateral kidney can be examined, as this will change therapy. This CT (of another infant) shows a right-sided mass; the intraoperative photo accompanies it:
In the US, surgeons use radiographic evaluation to “stage” the tumor. That is, if Wilms is suspected and the tumor is unilateral, without vascular involvement, and the child does not have a horseshoe kidney, intraoperative biopsy is forgone and a resection is performed immediately. Barring the above, adjuvant chemotherapy
is administered, followed by a nephron-sparing resection weeks later.
Wilms tumor is a success of modern oncology: although prognosis can vary, there is an overall 90% survival rate. Good outcomes depend on early recognition.
A two-year-old boy with behavior changes and a palpable mass may prompt the clinician to consider intussusception (A). Intussusception is the most common cause of intestinal obstruction in children 6 to 36 months; the peak age of presentation is 18 months; and the vast majority (90%) of cases present before age two. The typical presentation is severe, intermittent, crampy abdominal pain and vomiting. Although the child may appear normal between episodes, an alternative presentation is unexplained lethargy or sleepiness (thought to be from endorphin release from the enteral nervous system). Since most cases involve the ileocecal junction, if a mass is present, it is often described as a sausage-shaped mass in the right upper quadrant, leaving the right lower quadrant markedly scaphoid.
Chronic constipation (C) can cause fecal (stercoral) concretions (C) that cause a vicious cycle of withholding due to anticipated pain, and loss of normal signals to void. Encopresis (“overflow” of feces past the concretion) may result. A multimodal approach of diet, toilet training, stool softeners, and addressing family dynamics can be broached in the ED, but must be followed through with the child’s pediatrician for best results.
Children can be exposed to lead (D) from various sources (environmental, food-contamination, non-food ingestion) and early signs and symptoms may also be vague: decreased activity, decreased appetite, irritability, insomnia. Later neurologic (developmental delay, encephalopathy, seizures, coma), renal (interstitial nephritis), and hematologic (anemia, usually mild, hemolytic, and normocytic) sequelae develop.
Bottom line:
● Wilms tumor most commonly occurs in otherwise healthy children
● A palpable mass may be asymptomatic; consider the possibility especially in children under 5 years of
age with abdominal symptoms, hematuria, and/or hypertension
● Early recognition and intervention are essential in decreasing morbidity and mortality
References
Badeli H, Sajedi SA, Shakiba M. Simple Formulas for Screening Abnormal Blood Pressure in Children and Adolescents. Iran J Kidney Dis. 2010; 4(3):250-2.
Davenport KP, Blanco FC, Sandler AD. Pediatric Malignancies Neuroblastoma, Wilm’s Tumor, Hepatoblastoma, Rhabdomyosarcoma, and Sacroccygeal Teratoma. Surg Clin N Am. 2012; 92:745–767.
Siegel MJ, Chung EM. Wilms’ Tumor and Other Pediatric Renal Masses. Magn Reson Imaging Clin N Am. 2008; 16:479–497.
is administered, followed by a nephron-sparing resection weeks later.
Wilms tumor is a success of modern oncology: although prognosis can vary, there is an overall 90% survival rate. Good outcomes depend on early recognition.
A two-year-old boy with behavior changes and a palpable mass may prompt the clinician to consider intussusception (A). Intussusception is the most common cause of intestinal obstruction in children 6 to 36 months; the peak age of presentation is 18 months; and the vast majority (90%) of cases present before age two. The typical presentation is severe, intermittent, crampy abdominal pain and vomiting. Although the child may appear normal between episodes, an alternative presentation is unexplained lethargy or sleepiness (thought to be from endorphin release from the enteral nervous system). Since most cases involve the ileocecal junction, if a mass is present, it is often described as a sausage-shaped mass in the right upper quadrant, leaving the right lower quadrant markedly scaphoid.
Chronic constipation (C) can cause fecal (stercoral) concretions (C) that cause a vicious cycle of withholding due to anticipated pain, and loss of normal signals to void. Encopresis (“overflow” of feces past the concretion) may result. A multimodal approach of diet, toilet training, stool softeners, and addressing family dynamics can be broached in the ED, but must be followed through with the child’s pediatrician for best results.
Children can be exposed to lead (D) from various sources (environmental, food-contamination, non-food ingestion) and early signs and symptoms may also be vague: decreased activity, decreased appetite, irritability, insomnia. Later neurologic (developmental delay, encephalopathy, seizures, coma), renal (interstitial nephritis), and hematologic (anemia, usually mild, hemolytic, and normocytic) sequelae develop.
Bottom line:
● Wilms tumor most commonly occurs in otherwise healthy children
● A palpable mass may be asymptomatic; consider the possibility especially in children under 5 years of
age with abdominal symptoms, hematuria, and/or hypertension
● Early recognition and intervention are essential in decreasing morbidity and mortality
References
Badeli H, Sajedi SA, Shakiba M. Simple Formulas for Screening Abnormal Blood Pressure in Children and Adolescents. Iran J Kidney Dis. 2010; 4(3):250-2.
Davenport KP, Blanco FC, Sandler AD. Pediatric Malignancies Neuroblastoma, Wilm’s Tumor, Hepatoblastoma, Rhabdomyosarcoma, and Sacroccygeal Teratoma. Surg Clin N Am. 2012; 92:745–767.
Siegel MJ, Chung EM. Wilms’ Tumor and Other Pediatric Renal Masses. Magn Reson Imaging Clin N Am. 2008; 16:479–497.