PEDIATRIC SURGERY UPDATE ©
VOLUME 03, 1994

VOLUME 03 NO 01 JULY 1994

Bile-Plug Syndrome

Define as a partial or complete intraluminal obstruction of the extrahepatic bile ducts caused by an abnormal, viscous, inspissated bile. Clinical presentation is that persistent (conjugated) jaundice. This condition is associated to: massive hemolysis from Rh or ABO incompatibility, cystic fibrosis, TPN, and ileal resections. Ultrasound findings are: dilated gallbladder with sludge or stone formation, dilated common bile duct with sludge (echogenic appearance), and no acoustic shadowing. DISIDA shows no intestinal excretion of the radioisotope. Most cases subside spontaneously. Those associated to worsening of direct hyperbilirubinemia and liver function tests should be managed surgically. Irrigation of bile ducts with saline or N- acetylcysteine through the gallbladder is curative.

Gallstones

With the increase use of sonography in the work-up of abdominal pain, cholelithiasis is diagnosed more frequently in children. Gallstones occur as consequence of loss of solubility of bile constituents. Two types are recognize: cholesterol and bilirubin. Those of cholesterol are caused by supersaturation of bile (lithogenic) by cholesterol overproduction or bile salt deficiency. Bilirubin stones occur due to hemolysis (Sickle Cell, thalassemia) or bacterial infection of bile. Other etiologies include: Ascaris Lumbricoides infestation, drug-induced (ceftriaxone), ileal resection, TPN. etc. Gallbladder sludge is a clinical entity that when it persists can be a predisposing factor for cholelithiasis and cholecystitis. Management of symptomatic gallstones consists of laparoscopic cholecystectomy which has found to: reduce hospital stay, increase child return to normal activities, is well tolerated, low complication rate, but increases cost of procedure.

On HD Etiology

Hirschsprung's disease (HD) is characterized by lack of enteric ganglion cells, hyperplasia of abnormal nerve fibers and a non- propulsive, non-relaxing segment of bowel. Classically the etiology is attributed to a failure of cranio-caudal migration of parasympathetic neural crest cells to the distal bowel. A plausible explanation for the failure of relaxation of the bowel involved is a deficiency of enteric inhibitory nerves that mediates the relaxation phase of peristalsis. This nerves are intrinsic to the gut and are classify as non-adrenergic and non-cholinergic. Nitric oxide (NO) has recently been implicated as the neurotransmitter which mediates the relaxation of smooth muscle of the GI tract in HD. It's absence in aganglionic bowel might account for the failure of relaxation during peristalsis. Besides adhesions molecules (absent in aganglionic bowel) during early embryogenesis might restrict the neuro-ectodermal origin involved in the initial contact between nerves and muscle cell (synaptogenesis) suggesting that developmental anomaly of innervated muscle and absent NO causes the spasticity characteristic of HD.

CF Prenatal Diagnosis

Cystic Fibrosis is an autosomal recessive lethal disease affecting 1 in 2000 live newborns. Is caused by different mutations in the cystic fibrosis transmembrane conductance (CFTC) regulator gene. Prenatal diagnosis is possible to couples of carriers with a one- fourth risk of having an affected newborn. Reliability of the test is 98%. The sample is taken as chorionic villus (10-14 week gestation) or amniocentesis. A DNA polymerase chain reaction analysis has shown a major mutation in the delta F508 position (is a three base pair deletion in exon 10 which results in a protein without the amino acid phenylalanine at position 508) of the long arm of chromosome 7.

VOL 03 NO 02 AUGUST 1994

Intestinal Neuronal Dysplasia

Intestinal Neuronal Dysplasia (IND) is a colonic motility disorder first described in 1971 by Meier-Ruge associated to characteristic histochemical changes of the bowel wall (hyperplasia of submucous & myenteric plexus with giant ganglia formation, isolated ganglion cells in lamina propia and muscularis mucosa, elevation of acetylcholinesterase in parasympathetic fiber of lamina propia and circular muscle, and myenteric plexus sympathetic hypoplastic innervation),also known as hyperganglionosis associated to elevated acetylcholinesterase parasympathetic staining. The condition can occur in an isolated form (either localized to colon or disseminated throughout the bowel), or associated to other diseases such as Hirschsprung's (HD), neurofibromatosis, MEN type IIB, and anorectal malformations. It is estimated that 20-75% of HD cases have IND changes proximal to the aganglionic segment. Clinically two different types of isolated IND have been described: Type A shows symptoms of abdominal distension, enterocolitis, bloody stools, intestinal spasticity in imaging studies (Ba Enema) since birth, is less common and associated with hypoplasia of sympathetic nerves. Type B is more frequent, symptoms are indistinguishable from that of HD, with chronic constipation, megacolon, and repeated episodes of bowel obstruction. Management depends on clinical situation; conservative for minor symptoms until neuronal maturation occurs around the 4th year of life, colostomy and resectional therapy for life threatening situations.

Prenatal Cystic Hygroma

Cystic hygroma (CH) is an uncommon congenital lesion of the lymphatic system appearing as a multilocular fluid filled cavity most commonly in the back neck region, occasionally associated with extensive involvement of airway or vital structures. The etiology is intrauterine failure of lymphatics to communicate with the venous system. Prenatal diagnosis can be done during the first trimester of pregnancy as a huge neck tumor. Differential diagnosis includes teratomas, encephalocele, hemangiomas, etc. There is a strong correlation between prenatal dx and Turner's syndrome (> 50%), structural defects (Noonan's syndrome) and chromosomic anomalies (13, 18, 21). Early diagnosis (< 30 wk gestation) is commonly associated to those anomalies, non-immune hydrops and dismal outcome (fetal death). Spontaneous regression is less likely but can explain webbed neck of Turner and Noonan's children. Prenatal dx should be followed by cytogenetic analysis: chorionic villous sampling, amniocentesis, or nuchal fluid cell obtained from the CH itself to determine fetal karyotype and provide counseling of pregnancy. Late diagnosis (>30 wks) should be delivered in tertiary center prepare to deal with dystocia and postnatal dyspnea of newborn. The airway should be secured before cord clamping in huge lesions.

GER and RS

Although a fundoplication is effective in controlling gastroesophageal reflux (GER), it could be less effective in curing respiratory symptoms (RS) such as aspiration, apnea, choking, chronic cough and wheezing attributed to reflux in children. The problem is documenting a cause-effect relationship between GER and RS. Objective parameters used are the ZMD (mean duration of reflux episodes during sleep by 18-24 hr ph-study), isotopic tracing in lung during milk scintigrams and sx preceded by a drop in ph. A ZMD > 4 min can be a reliable preop sign the antireflux surgery will cure the RS. Reversible obstructive airway disease pts. are more prone to suffer from GER secondary to RS with less chances of being relieved by fundoplication. Neurologically impaired child with RS has highest rate of failure. Medical tx and transgastric jejunostomy feeding are effective for poor operative risk pts.

VOL 03 NO 03 SEPTEMBER 1994

TPNIC

TPN induced cholestatic (TPNIC) jaundice is an uncommon conjugated hyperbilirubinemia in infant which carries serious implications. Infectious, metabolic, and structural causes of cholestasis should be rule-out. The incidence of TPNIC is around 30-50% of infants receiving prolonged TPN. Very low birth weight and prematures are more at risk than term infants. No single etiologic factor has been identified, although large amounts of amino acids associated to low amounts of fat in the TPN solution can cause sludge and stone formation in the gallbladder. The most important factor in the hepato-biliary dysfunction is the patient underlying disease state and severity of his illness. TPNIC is a predisposing factor for sepsis in surgical neonates since it leads to impaired non-specific cellular immunity. Cholestasis is associated with intracranial hemorrhage, PDA, sepsis, and GI conditions requiring surgery. This infants will show markedly elevated liver enzymes, no excretion of Tc labeled HIDA and increased GGT levels. Liver histology correlates with the chronologic progression of the disease process and TPN use as follows: by 5 days of TPN you can find steatosis with prominent eosinophils in portal tracts, by 10 days there is canalicular cholestasis, by 21 days bile duct proliferation, by 90 days portal fibrosis and after 5 months micronodular cirrhosis. Phenobarbital which increase bile flow has not been found beneficial in TPNIC. In most cases the degree of dysfunction is self-limiting and reversible upon cessation of TPN.

GER and NI

Feeding disturbances, vomiting, anticonvulsant drug non-compliance, and recurrent chest infections in neurologically impaired (NI) children often request the effort of surgical options to improve growth, nutrition, quality of life and reduce seizure activity. Options are enteral tube feeding, percutaneous endoscopic gastrostomy (PEG), and open gastrostomy with or without antireflux surgery (ARS). Whenever a NI child is referred for feeding gastrostomy a expeditious search for gastroesophageal reflux (GER) is achieved and ARS considered. ARS in NI has a higher rate of complication than in non-NI children (4:1). They include: wrap herniation into chest (entire or paraesophageal), disruption and recurrent preop GER symptoms (vomiting and pneumonia are the most troublesome). The etiology of NI offers little help in predicting success of ARS. Theories explaining this high rate of failure are: supine position, swallowing incoordination, esophageal dysmotility, spasticity, seizures, delayed gastric emptying, chronic constipation and scoliosis (increase intrabdominal pressure). Not every NI child requires ARS in the presence of GER. Improving nutrition can decrease GER symptoms. PEG can help improve nutrition and serve as a screening tool for those pts. with continuing GER related problems who will eventually need ARS. Ballantine permanent roux-en-y jejunostomy is another alternative in pts. with persistent feeding intolerance after ARS.

WT and HA

In 1967 hyaluronic acid (HA), a glycosaminoglycan is detected in the serum and urine of a patient with a Wilm's Tumor (WT). HA has also been found in children with WT to: cause serum hyperviscosity , suppress the formation of humoral precipitating antibodies to certain major classes of proteins (interfering with elicitation of a complete antibody response), and produce platelet dysfunction presenting as coagulopathy suggesting Acquire von Willebrand disease. The group from UCSF School of Medicine postulated that since the fetal kidney is the source of circulating HA stimulating activity and WT is an embryonal tumor, HA could serve as a WT tumor marker. A cooperative study started in 1990 gathered data for 105 pts proved that: HA urine levels in WT pts are high preop, decrease with tumor resection and persist high with tumor persistence or relapse (APSA 94).

VOL 03 NO 04 OCTOBER 1994

Acute Pancreatitis

Acute pancreatitis (AP) is unusual in the pediatric patient, can affect all age groups and should be considered in children presenting with acute abdominal complaints Causes are diversely and clinical course less severe. The three most common etiological factors are: trauma, drug-induced, and biliary tract disorders. Other factors to consider are: infections (mumps, ascaris, adenovirus), metabolic (branched-chain organic acidemias), structural defects (anomalous union of pancreatico-biliary ductal system), and hereditary. Blunt abdominal trauma is the leading cause (20-30%)of AP by crushing the fixed organ between the spine. Drugs associated to the development of AP are: steroids, L-asparaginase, valproic acid, acetaminophen (drug withdrawal is treatment of choice). Biliary disorders related to AP are gallstone and choledochal cysts by causing transient ductal obstruction. Most common complaint of children with AP is abdominal pain. Diagnosis is confirmed with elevated amylase/lipase in serum and urine (lipase is more specific since pancreas is major source). Imaging studies of utility are US, CT-Scan and ERCP. The use of ERCP in previously idiopathic cases of AP have increased the yield of diagnosing anomalous pancreatico-biliary junctional defects. Management during early phase is supportive with IV therapy, NG decompression, NPO (to decrease acid stimulation and prevent secretin release), and nutritional (TPN). Surgery is rarely required except complications such as abscess and pseudocyst formation.

Water in Neonates

Water represents 70-80% of body weight of normal neonates and premature babies respectively. Total body water (TBW) varies inversely with fat content (prematures have less fat deposits). TBW is distributed into 1/3 extracellular (ECF) and 2/3 intracellular (ICF) fluids compartments. The ECF is composed of plasma volume (4-5% body weight), intersticial and transcellular fluids. There is a change in body water upon entrance of the fetus to his new extrauterine existence; A gradual decrease in TBW and ECF, and an increase in the ICF. This shift is interrupted with a premature birth. Inappropriate IV therapy can lead to persistent PDA, bronchopulmonary dysplasia, NEC, and intraventricular hemorrhage. Insensible water losses are from lung (1/3) and skin (2/3). Transepithelial (skin) water loss is the major component and decreases with increase in postnatal age. Radiant warmers and phototherapy increase insensible losses. Newborns produce a urine output of 2 cc/kg/hr to clear the osmotic solute load at an osmolality of 250 mOsm/kg. Their kidney have a low glomerular filtration rate and concentrating ability (limited urea in medullary interstitium) and are therefore less tolerant to dehydration. Electrolytes requirement of full-term: Na 2meq/kg/day, K 2 meq/kg/day at a rate of fluid of 100cc/kg/24 hrs for the first 10 kg of weight.

Hepatoblastoma

Hepatoblastoma (HB) is the most common primary malignant neoplasm of the liver in children mostly seen in males less than four year of age. Diagnostic work-up (US, Scintigraphy, CT-Scan) objective is predicting resectability and tumor extension. Diagnostic laparotomy will decide resectability. Markers associated to this tumor are: alpha-fetoprotein and gamma-glutamyltransferase II. Only reliable chances of cure is surgical excision although half are unresectable at dx. Unresectable tumors can be managed with preop chemotx. Disadvantages of preop chemotx are: progressive disease, increase morbidity, post-op complications, and toxicity. Advantages are: decrease in tumor size, covert three-fourth cases into resectable, although extent of surgery is not decreased. Tumor necrosis is more extensive in pt. receiving preop chemotx. Osteoid present in tumors after chemotx may represent an inherent ability of the tumor to maturate and differentiate. Diploid tumors on DNA flow cytometry show a better prognosis.

VOL 03 NO 05 NOVEMBER 1994

CVC Sepsis

Central Venous Catheter (CVC) placement has improved care and survival of sick infants. Catheter sepsis with an incidence of 10-30% remains the most common complication of CVC insertion. Defined as an apparent clinical infection in a patient with a CVC proven by positive blood culture when no other source can explain it. Principal isolated organism is coagulase-negative staphylococci (CONS). These organisms are associated to foreign body placement (V-P shunts, CVC, etc.) due to their adherents properties. Although contamination of the catheter can occur during insertion or subsequent care, catheter hub contamination is the primary site of entry of organism with secondary colonization of the tip. The mechanism of infection is a poorly cleaned entry site. Factors which increase the incidence CVC sepsis are: younger age, primary diagnosis, use of TPN (lipid emulsions), multiple catheter use, thrombus and fibrin sheath formation. Management of definite CVC sepsis consists of antibiotics or removal. The use of urokinase and antibiotics can effectively and safely manage these episodes leading to more than 90% of infected catheter salvage. Persistent multiple organisms or fungal sepsis will need catheter removal. A dilemma is to leave a possible infected or remove a non-infected catheter. AOLC (Acridine-orange leucocyte cytospin) test is specific and sensitive in rapidly (one hour) distinguishing catheter septicemia when compared with NBT and CRP. Catheter care should include: skin disinfection of catheter exit site with two 10-second application of povidone swabs every 24 hour, and occlusion with a sterile semipermeable dressing. Low-dose vancomycin added to TPN solutions has eliminated CONS-CVC sepsis and increased useful catheter life. Staff training in caring for CVC will reduce the incidence of CVC related-sepsis.

Bezoars

Bezoars are rare foreign body concretions formed in the stomach and small bowel composed mainly of hair (tricho), vegetable matter (phyto) or milk curds (lacto). Most cases are females children, 6-10 years old, with bizarre appetite (trichophagia) and emotional disturbances. Originally the mass forms in the stomach and can move to the small bowel by fragmentation, extension or total translocation. Diagnosis can be confirmed by UGIS, CT-Scan or endoscopy. The child can develop an asymptomatic palpable abdominal mass, pain, obstruction or perforation. Other children will reduce intake and develop weight loss. Predisposing conditions to bezoar formations are: gastric dymotility and decreased acidity. Management can consist of mechanical or pulsating jet of water fragmentation via the endoscope, operative extraction, shock-wave lithotripsy (ESWL) with subsequent evacuation, or dissolution by oral ingestion of proteolytic enzymes (papain, acetylcysteine, cellulase). With ESWL the shock wave pressure needed is less than half used for urolithiasis cases.

Cytokines

Cytokines (CK) are proteins produced by our own cells (macrophages, lymphocytes, mast cells, fibroblasts, etc.) which modulate the acute phase of inflammation after injury, infection and neoplastic growth. They play a key role in control of hemopoiesis and immunity. Characterized so far: tumor necrosis factor (TNF), interleukin (IL) 1 to 6, recently 8, and interferon. Recombinant technologies have made them available. CK enhances neonatal myeloid progenitor proliferation, modulates neonatal bone marrow neutrophil storage and proliferation pools, induces peripheral neutrophilia and protects against the increase mortality associated with bacterial sepsis. Early postoperative increases in plasma IL-6 and IL-8 represent the stress response of neonates to surgery with an exaggerated response during postop complications. IL-6 is responsible for the acute phase response, and IL-8 with marked chemotactic property.

VOL 03 NO 06 DECEMBER 1994

SCT

Sacrococcygeal teratoma (SCT) is the most common extragonadal germ cell tumor in neonates with an incidence of one in 30-40,000 live births. Three-fourth are females. SCT present as a large, firm or more commonly cystic masses that arise from the anterior surface of the sacrum or coccyx, protruding and forming a large external mass. Histology consist of tissue from the three germ cell layers. SCT is classified as: mature, immature, or malignant (endodermal sinus) and produces alpha-feto protein (AFP). Prenatal sonographic diagnostic severity criteria are: tumor size greater than the biparietal diameter of the fetus, rapid tumor growth, development of placentomegaly, polyhydramnios and hydrops. Large tumors should benefit from cesarean section to avoid dystocia or tumor rupture. Management consist of total tumor resection with coccyx (recurrence is associated with leaving coccyx in place). Every recurrence of SCT should be regarded as potentially malignant. Malignant or immature SCT with elevated AFP after surgical resection will benefit from adjuvant chemotherapy. Survival is 95% for mature/immature tumors, but less than 80% for malignant cases. Follow-up should consist of (1) meticulous physical exam every 3-6 months for first three years, (2) serial AFP determination, (3) fecal/urodynamic functional studies. Long term F/U has found a 40% incidence of fecal and urinary impairment associated to either tumor compression of pelvic structures or surgical trauma.

Grave's

Hyperthyroidism in children is caused by a non-immune autonomous adenoma (rare), hyperfunctional nodular goiter (less frequent), or more commonly diffuse immunogenic gland enlargement (Grave's Disease). Grave's children manifest initial neurologic symptoms and tachycardia. Management consist of: (1) medical- antithyroid drugs, hormone substitution, and iodine therapy, (2) surgical excision, or (3) radio-iodine therapy (not routine used due to possible induction of malignancy). After two years of antithyroid drug therapy hyperthyroidism recurs in 40-70% of cases. The only factor predicting remission with drug tx is absence of ophthalmopathy. Main disadvantages of antithyroid drugs are the need for prolonged treatment and risk of recurrence. Indications for surgery are: poor compliance with drug tx, recurrent hyperthyroidism after prolonged (two years) drug tx, side effects to drugs (neutropenia, vasculitis, etc.), a cosmetically unpleasant or obstructive symptomatic goiter. Before surgical therapy clinical and biochemical euthyroidism should be obtained. Extent of resection is debatable and depends on: surgical expertise, extent of recurrent hyperthyroidism (8-12% incidence), and rate of hypothyroidism complications. Most prefer subtotal thyroidectomy (retaining 6-10 GM of tissue), other total gland removal. Surgical complications are: recurrent nerve paralysis, temporary or permanent hypoparathyroidism, and post-op thyrotoxic crisis. Ophthalmopathy is less severe and disappears when euthyroidism is obtained. Lymphocytic infiltration if found in three-fourths of glands removed.

LH-RH

Gonadotropin releasing hormone (LH-RH) is a decapeptide that when used as nasal spray will cause descend of one-third of unilateral palpable undescended testis, effect potentiated with the subsequent use of Human Chorionic Gonadotropin. Treatment is more effective the younger the age of the boys and the near is the testis to the scrotum. LH-RH is recommended as initial therapy of testicular non-descent because is non-invasive, has good response in younger age groups, and limited side-effects. The number of germ cells per tubule (fertility index) increases in patient who responds to LH-RH. Contraindications for hormonal therapy are: (1) coexistent inguinal hernia or hydrocele testis, and (2) previous inguinal operation. High non-palpable testis have poor response to hormonal therapy.