Ascites in a 2-Month-Old Infant With Decreased Urine Output and Irritability

A 2-month-old infant who was previously healthy and born at 39 weeks and 1 day, currently weighing 4.4 kg (fourth percentile), presents for a telemedicine visit with the pediatrician for concern for poor growth with abdominal distention. She was previously taking more than 20 ounces of expressed breast milk daily and growing well but has been taking less than 12 ounces per day and her weight has not increased over the last 3 weeks (3 weeks ago she was also 4.4 kg, then the 13th percentile). Of note, the patient had her 2-month-old well-child check, including vaccines (DTaP-IPV/Hib, Hep B, PCV13, rotavirus) 1 week prior to this telemedicine visit, where she persistently weighed 4.4 kg. At this well-child check, the family was instructed to supplement with formula and track her weights daily, which prompted the telemedicine visit for zero weight gain. At this telemedicine visit, the family expresses concern that per their home scale, the patient has not gained weight in 7 days, since her well-child check. The pediatrician notices a bruise on the patient’s cheek and instructs the family to come into the clinic immediately, but the family presents to the clinic the next day. During this clinic visit, the patient’s mother expresses concern that she becomes more irritable when her abdomen is touched and that the abdomen appears more distended over the last week. On review of systems, her mother reports that she has had decreased urine output and increased spitting up and has been crying more and smiling less. When asked about the bruise on the cheek, the family denied known trauma and easy bruising or nosebleeds. The pediatrician immediately sent the family to the emergency department (ED).On examination at ED presentation, she is sleeping but rousable and subsequently fussy but easily consolable. Her vital signs are as follows: blood pressure 80/51 mm Hg, pulse 131 bpm, temperature 98.9 °F, respirations 43 breaths per minute, and oxygen saturation 100%. Her weight is 4.44 kg; there was no documented head circumference. She is normocephalic without retinal hemorrhages, hemotympanum, or mucosal lesions; has flat fontanelles and full range of motion of her neck; and is with normal cardiac rate and rhythm and with clear lung fields. Her abdomen is visibly distended with increased bowel sounds but does not produce irritability to palpation; she does not have any hepatosplenomegaly or abdominal masses. Her neurologic examination reveals normal tone, and she is able to fix and follow the examiner. She has the bruise on her right cheek and has no other bruises, abrasions, or skin rashes. Her laboratory results are as follows: sodium 128 mmol/L, potassium 5.3 mmol/L, chloride 97 mmol/L, bicarbonate 20 mmol/L, blood urea nitrogen 7 mg/dL, creatinine 0.27 mg/dL, calcium 9.7 mg/dL, prealbumin 10.5 mg/dL (18.0–44.0), C reactive protein 2.5 mg/dL (<1.0), white blood cell count 12.7 × 103/μL, hemoglobin 9.2 g/dL, hematocrit 28.3%, lactate dehydrogenase 470 U/L (500–920), alkaline phosphatase 167 U/L (80–425), alanine aminotransferase 17, aspartate aminotransferase 38, prothrombin time 13.6 seconds, international normalized ratio 1.0, and partial thromboplastin time 25.8 seconds. Abdominal ultrasound in the ED revealed a moderate amount of ascites in all abdominal quadrants as well as mild right hydronephrosis with debris in the collecting system and the bladder. Upper gastrointestinal fluoroscopy confirmed these findings and also revealed rib fractures. A skeletal survey discerned healing rib fractures, and head computed tomography (CT) was unremarkable. A CT of her abdomen revealed mild hydronephrosis of uncertain etiology with 2 punctate areas of increased density concerning for extravasated contrast, which the radiologists believed may indicate ureteropelvic injury (Figure 1). To further evaluate the hydronephrosis and concern for genitourinary tract involvement, the patient underwent a retrograde pyelogram, which was initially unremarkable. The patient then had a paracentesis with placement of a peritoneal drain. In the initial fluid collected, the ascites–serum creatinine ratio was not elevated. Fluid analysis days later, however, was notable for elevated creatinine, confirming a leakage of urine into the abdomen. A repeat retrograde pyelogram after drain placement and ascites drainage did in fact reveal extravasation of contrast consistent with a leak at the right ureteropelvic junction (Figure 2).The differential diagnoses for abdominal ascites include vascular leak issues secondary to a generalized inflammatory response and direct injury to abdominal organs. A difference in the pressure gradient of vessels can be caused by increased plasma volume from salt and subsequent water retention (eg, from primary renal disease or heart failure), outflow obstruction (eg, venous obstruction secondary to hepatic cirrhosis), decreased oncotic pressure (eg, hypoalbuminemia secondary to protein-losing enteropathy, liver failure, or nephrotic syndrome), or increased capillary permeability (eg, sepsis and burns). Intra-abdominal trauma causing fluid leak can also create ascites. Contusions, lacerations, and other intra-abdominal trauma can lead to leakage of blood, urine, or intestinal contents and are additional etiologies of ascites. Nonaccidental trauma (NAT) should be a part of the differential diagnosis in infants presenting with acute abdominal distention, as abused children have higher rates of solid organ injuries than nonabused children and may have a delay in seeking care, and the history provided is frequently vague.1,2The ascites of the patient was attributable to urine leak due to ureteropelvic junction (UPJ) injury likely secondary to blunt abdominal trauma from NAT in this nonmobile infant. On initial testing of the fluid, the ascites–serum creatinine ratio was not elevated. The fluid that was tested had been sitting in the peritoneal cavity for an unknown amount of time; therefore, the peritoneum, effectively, was a dialyzing membrane, normalizing the creatinine ratio. Additionally, the initial retrograde pyelogram did not reveal extravasation of contrast because the high volume of the ascites fluid acted as a tamponade to the ureter laceration. After several days of abdominal fluid drainage, repeat testing of the actively draining fluid and repeat imaging via pyelogram was done to reassess and revealed a laceration in the ureter and urine in the abdomen (Figure 2). The diagnosis of nonaccidental trauma also accounts for the healing rib fractures and the previously noted cheek bruise. After head injuries, abdominal injuries are the most common cause of death in abused children.2 In 25% of children younger than age 1 year who are hospitalized for abdominal trauma, that trauma is found to be the result of abuse.2 Although any abdominal injury pattern may be observed with NAT, a high index of suspicion should be maintained for organ injuries. Bruising in nonambulatory children and delay in seeking care is also suggestive of abuse.2,3Children with intra-abdominal trauma may present with abdominal distention, vomiting, and undernourishment. Abdominal abuse in young children is often challenging to discern based on external skin examination (ie, bruising) because there is significant elasticity in the external abdominal wall vessels (ie, underneath the skin) and these vessels therefore are more likely to stretch instead of rupture with blunt trauma, preventing external contusion as evidence of potential internal damage.3 Injury in children with abdominal trauma usually involves at least 1 episode of significant blunt, direct compressive force.3Visceral injury in NAT, despite being more common than in nonabused children, is still rare and is believed to occur in less than 2% of physically abused children. Physical signs of prior abuse such as bruising, burns, or bone fractures have been observed in approximately 65% of patients with later-confirmed NAT.2 Other injuries concerning for NAT include abrasions in atypical locations, fractures in atypical locations, or head trauma in immobile children, or bites, burns, or injuries to the genitalia.2,3With abdominal trauma, any organ can be injured. The most commonly injured abdominal organs are the liver, followed by injuries of the spleen, pancreas, kidney, and gastrointestinal tract, as they are mostly fixed to the epigastrium and unprotected by the ribs and therefore more vulnerable to direct compressive forces.2,4 The kidneys are less commonly injured because these organs are retroperitoneal and therefore have more protection by overlying abdominal layers of tissue.4 Injury of the ureter is exceptionally rare.4 Although the incidence of ureteral injury within abdominal organ trauma is less than 1%, a delayed diagnosis may lead to significant morbidity, such as urosepsis.5When considering imaging to evaluate for suspected NAT, any delay in seeking care, ecchymosis in nonambulatory children, suspicion for organ injury, or young age warrants further evaluation. CT of the abdomen and pelvis with intravenous contrast is the modality of choice for an abnormal abdominal examination.5 In the case of urogenital injury, CT imaging would be expected to reveal extravasation of intravenous contrast.4A sentinel injury is a medically mild, superficial injury that occurs in infants who are developmentally unable to obtain the injury themselves.6,7 There is a high sensitivity and specificity for physical abuse in a child younger than age 4 months presenting with any bruising.6 Because infants are at the highest risk of child abuse, it is imperative for primary care providers to have a high index of suspicion for abuse in any child presenting with a sentinel injury.6Ascites is managed by first removing the fluid from the abdomen via therapeutic/diagnostic paracentesis and often subsequent peritoneal drain placement to continue to drain existing fluid and any newly accumulating fluid.5,6 The most important aspect of ascites management is identifying the source of the fluid—in this case, urine leakage from trauma to the ureter. The course of management for UPJ injury depends on the degree of traumatic avulsion.5 A partial-tear injury may be managed with endourological care, whereas a complete-tear injury requires uretero-ureterostomy care. The standard of care is surgery with pyeloplasty approximately 12 weeks after injury, to allow for any ascites resolution, with a percutaneous nephrostomy in the interim.5Management of child abuse requires the providers to contact the appropriate state child protective services (CPS) for further investigation. Furthermore, it is imperative for all providers to remark and further inquire and workup any sentinel injuries, such as the cheek bruise on physical examination at initial presentation in this immobile child. Identifying and further investigating injuries that are not consistent with the age and development of the child may allow the provider to act early in the child abuse course and prevent further injury and possibly death.The Child Abuse Pediatrics team, social work, and CPS were consulted. The family repeatedly denied any inflicted abuse. A repeat skeletal survey done 2 weeks after the first showed healed rib fractures. For her abdominal injury, the patient had a paracentesis with subsequent peritoneal drain placement to manage her ascites, which improved with drainage. For her UPJ injury, the urology team placed a Foley catheter and subsequently a percutaneous nephrostomy. The patient underwent repair of her UPJ injury approximately 12 weeks after admission following complete resolution of the ascites. She was restarted on a regular diet, which she tolerated well, and climbed to near the 50th percentile for growth prior to discharge approximately 1 month later. Her mother and father were suspected to be the perpetrators. She was discharged in the care of her paternal grandmother and grandfather, who did not live in the household, per court decision.It is imperative that providers maintain a high clinical suspicion for occult trauma in patients who present with a sentinel injury.The most commonly injured abdominal organs in NAT are the spleen, liver, intestines, and pancreas.The peritoneal membrane can act as a dialyzing membrane, making the diagnosis of a urine leak difficult.CT is the imaging modality of choice to diagnose abdominal injury.