Symptom-Based Diagnosis in Pediatrics (CHOP Morning Report) 1st Ed.

CASE 15-2

Six-Week-Old Boy

STACEY R. ROSE

HISTORY OF PRESENT ILLNESS

A 6-week-old full-term boy was referred by his pediatrician for persistent jaundice and poor weight gain. The infant was seen by his pediatrician during the first week of life after the mother noted that he “looked yellow.” At that time, he was otherwise doing well and the pediatrician diagnosed physiologic jaundice. He was brought to the pediatrician today for a well visit and it was noted that the patient was still jaundiced. Additionally, the patient has not gained any weight since his first visit at week 1 of life.

The infant is being fed a cow milk-based formula. The patient’s mother reports that he has frequent episodes of emesis. She also reports that the infant has been increasingly fussy during feeds. She denies that the infant has had any diarrhea, fever, bleeding, or bruising.

MEDICAL HISTORY

The infant was born at 38 weeks gestation by vacuum-assisted vaginal delivery. His birth weight was 3.2 kg. Maternal prenatal labs were normal. His hospital stay was unremarkable and he was discharged home with her mother on his second day of life.

The infant has a healthy 3-year-old brother. There was no family history of jaundice, liver disease, anemia, or familial blood disorders.

PHYSICAL EXAMINATION

T 37.0°C; HR 136 bpm; RR 32/min; BP 88/60 mmHg; Weight 3.25 kg (<5th percentile); Length 52 cm (10th-25th percentile); Head Circumference 37 cm (10th-25th percentile)

On examination, the patient was fussy but consolable by his mother. He was jaundiced with an open, flat fontanelle. He did not have any dysmorphic features. Scleral icterus was present. The lung and cardiac examinations were normal. His abdomen was soft and nondistended with normoactive bowel sounds. A smooth, firm liver edge was palpable 2 cm below the costal margin. Additionally, there was a 4 cm soft, mobile nontender mass noted in the right upper quadrant. The genitourinary, extremity, and neurologic examinations were all normal.

DIAGNOSTIC STUDIES

Complete blood count: WBC, 6900/mm3 (neutrophils: 43%, lymphocytes: 48%); hemoglobin, 11.2 g/dL; platelets, 332 000/mm3. Liver function tests: total bilirubin, 9.5 mg/dL; direct bilirubin; 8.4 mg/dL; albumin, 3.2 mg/dL; ALT, 167 U/L; AST, 188 U/L; alkaline phosphatase, 641 U/L; gamma glutamyl transferase, 524 U/L. Serum electrolytes: normal. Urinalysis: normal.

COURSE OF ILLNESS

The patient underwent several imaging studies and was admitted for urgent evaluation of his abdominal mass and cholestatic jaundice. A contrast gastrointestinal series suggested the diagnosis (Figure 15-4).

Image

FIGURE 15-4. Gastrointestinal contrast series reveals a large lucent structure in the right upper quadrant with compression of the transverse colon.

DISCUSSION CASE 15-2

DIFFERENTIAL DIAGNOSIS

The presence of an abdominal mass requires urgent evaluation. Most abdominal masses in the neonatal period are renal in origin and include hydronephrosis, multicystic dysplastic kidneys, polycystic kidneys, or Wilm tumor. Other common causes include neuroblastomas, hepatomas, choledochal cysts, GI duplication cysts, pyloric stenosis (the “olive” of pyloric hypertrophy), ovarian cysts, or teratomas. Because this patient’s mass was soft and mobile, it is most consistent with a nonretroperitoneal cystic structure.

Additionally, the patient has a persistent conjugated hyperbilirubinemia with elevations in alkaline phosphatase and gamma-glutamyl transferase consistent with neonatal cholestasis, a condition that results from accumulation of bile components in the blood due to impaired bile flow or excretion. There are a wide variety of causes, several of which require immediate intervention and hence prompt diagnosis and treatment are crucial.

Causes of neonatal cholestasis may be subdivided into various categories. Obstructive causes include biliary atresia, choledochal cyst, cholelithiasis, and paucity of intrahepatic bile ducts (Alagille syndrome). Though less common, some of the abdominal masses listed above, such as neuroblastomas, teratomas, or GI duplication cysts, can also cause cholestasis by compressing the biliary tree. Infectious, metabolic, or iatrogenic conditions may also be present, as outlined below (Table 15-4).

TABLE 15-4. Causes of cholestatic jaundice in the neonate.

Image

DIAGNOSIS

The patient had an abdominal ultrasound to assess the mass and hepatomegaly which revealed a 3.8 cm × 1.9 cm × 2.5 cm cystic structure inferior to the liver and adjacent to the right kidney, consistent with a choledochal cyst . Ultrasound also revealed a mildly enlarged liver and normal gallbladder. He had a hepatobiliary scan that failed to show tracer excretion into the small intestine. The gastrointestinal series showed a cystic structure in the right upper quadrant compressing the transverse colon (Figure 15-4). The structure was later identified as a choledochal cyst.

INCIDENCE AND ETIOLOGY

Choledochal, or biliary, cysts are cystic dilations in the biliary tree involving both intrahepatic and extrahepatic structures. They are a rare disorder, with an estimated incidence of 1:13 000 to 1 in 2 million. There is a 3:1 girl to boy predominance and some reports of familial occurrence. Incidence is highest in Asian countries, particularly Japan where more than half of the reported cases arise. Most cysts are thought to be congenital but some may be acquired. The pathophysiology remains unclear but leading theories suggest that they form due to the reflux of pancreatic enzymes into the common bile duct, which causes inflammation, weakness, and dilation of the duct. Other theories suggest an infectious cause related to fetal viral infection or abnormal in utero proliferation of biliary epithelial cells.

Biliary cysts have been divided into five sub-types (Table 15-5). Type I and IV cysts are the most common.

TABLE 15-5. Todani classification of biliary cysts.

Image

CLINICAL PRESENTATION

While choledochal cysts are most commonly seen in infants and children; an increasing number of patients are now diagnosed in adulthood. The classic pediatric presentation is a triad of abdominal pain, jaundice, and a palpable mass, though few patients present with all three symptoms in practice. Other common features in infants include failure to thrive, vomiting, and fever. Symptoms differ in older children and adults. An abdominal mass is rare and instead, many present with recurrent cholangitis, intermittent jaundice, and pancreatitis. If undetected, severe liver dysfunction, ascites, and coagulopathy may develop. Furthermore, there is a strong association between choledochal cysts and biliary malignancy, particularly in adult patients.

DIAGNOSTIC APPROACH

Abdominal ultrasound. Abdominal ultrasound is very effective in diagnosing choledochal cysts, particularly in infants or children and in adults if there is a high index of suspicion. Many cysts are now detected by prenatal ultrasound.

Direct cholangiography. The best method for definitive diagnosis of choledochal cyst or for delineating the precise cyst type and anatomy is by magnetic resonance cholangiopancreatography (MRCP) which has largely supplanted endoscopic retrograde cholangiopancreatography (ERCP) as the diagnostic test of choice because MRCP offers higher resolution of relevant anatomy. Less commonly used diagnostic options include percutaneous transhepatic cholangiography and intraoperative cholangiography. These techniques allow direct visualization of the involved biliary structures and help identify the presence of an anomalous pancreaticobiliary junction.

Other modalities. CT scanning may be used to delineate the cyst and its relationship to surrounding structures. Gastrointestinal contrast series, though performed in this case, are no longer routinely performed to diagnose choledochal cysts.

TREATMENT

The preferred treatment is surgical excision of the cyst and a roux-en-Y choledochojejunostomy. Complications from untreated cysts include recurrent cholangitis, pancreatitis, and biliary malignancy.

The infant was taken immediately to the operating room where he underwent direct cholangiography that revealed a choledochal cyst with dilation of the intrahepatic bile ducts and passage of contrast into the duodenum. The cyst was resected and a roux-en-Y hepatic jejunostomy was performed. The patient initially required parenteral nutrition but enteral feeds were slowly reintroduced as he recovered. One week after surgery, he was tolerating full feeds. His conjugated hyperbilirubinemia gradually improved and his direct bilirubin at the time of discharge had decreased to 2.6 mg/dL.

SUGGESTED READINGS

1. Lipsett PA, Pitt HA, Colombani PM, et al. Choledochal cyst disease: A changing pattern of presentation. Ann Surg. 1994;220:644-652.

2. Lipsett PA, Henry AP. Surgical treatment of choledochal cysts. J Hepatobiliary Pancreat Sci. 2003;10:352-359.

3. Suchy FJ. Cystic diseases of the biliary tract and liver. In: Behrman RE, Kliegman RM, Arvin AR, eds. Nelson’s Textbook of Pediatrics. 17th ed. Philadelphia, PA: WB Saunders Co.; 2004:1343-1345.

4. Topazian M. Biliary cysts. UpToDate. http://www.uptodate.com/contents/biliary-cysts. Updated September 24, 2010. Accessed September 1, 2010.