GASTROINTESTINAL SYSTEM
B. Chronic Liver Failure 1. Definition
5. Clinical Presentation a. History
b. Physical examination 6. Signs and Symptoms
a. Staging of hepatic encephalopathy
i. Stage I. Normal level of consciousness, periods of lethargy and euphoria
ii. Stage II. Disorientation, increased drowsiness, and agitation with mood swings
iii. Stage III. Marked confusion, sleeping most of the time
iv. Stage IV. Coma
b. Jaundice. Yellow discoloration of the skin, mucous membranes, and sclera is caused by excessive bilirubin levels.
c. Renal-failure symptoms depend on the type of renal failure the child is experiencing. Azotemia should be evaluated carefully in the presence of hepatic failure, as nitrogenous wastes cannot be metabolized appropriately. Increased serum creat- inine levels and oliguria are present.
d. Coagulopathy is recognized by an ele- vated PT. A PT that is uncorrectable despite IV vitamin K (AquaMEPHYTON) administra- tion reflects significant parenchymal disease.
In addition, there will be platelet dysfunc- tion. Other signs include bruising and bleed- ing from mucosal surfaces and the presence of petechiae.
B. Chronic Liver Failure
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fat-soluble vitamins (A, D, E, and K). Poor weight gain and deficiencies of vitamin A (caus- ing atrophy of the epithelial tissue and night blindness when severe), vitamin D (causing rick- ets), vitamin E (causing muscle degeneration, megaloblastic anemia, hemolytic anemia, creat- inuria, target cell anemia, spur cell anemia, and peripheral neuropathy), and vitamin K (causing hypoprothrombinemia resulting in coagulopa- thy) are noted. Adequate glucose is necessary to maintain normal blood glucose levels.
e. Pruritus is related to bile salt deposition on the epidermis related to defective biliary drain- age causing an accumulation of pruritogens.
Constant itching can be accompanied with skin breakdown and secondary infection.
f. Asterixis. “Liver flap” is a flapping tremor of the hand noted when both arms are raised with forearms fixed and the hands dorsiflexed.
g. Rickets are caused by an abnormal bone for- mation related to a deficiency of vitamin D, cal- cium, and phosphorus. Pathologic fractures and bone malformations result.
h. Telangiectasis (vascular spiders, spider angi- omas, spider nevi) are skin lesions consisting of a central arteriole from which smaller vessels radiate. Spontaneous bleeding from lesions can occur.
i. Xanthomas are fatty nodules that develop in the SC skin layer due to disturbances in lipid metabolism.
5. Signs and Symptoms of Chronic Liver Disease a. Jaundice
i. Seen with both acute and chronic liver failure
ii. Accumulation of yellow pigment in the tissues
iii. Cephalocaudal distribution:
• Head and sclera = 5
• Trunk = 10
• Distal extremities = 15 6. Diagnostic Tests
a. Comprehensive blood chemistries, hematol- ogy and coagulation studies, US, CT scan, liver biopsy, endoscopy, and LFTs (see Table 7.2) may be useful in the determination of pathology as described previously.
7. Patient Care Management
a. Disease specific preventive care
b. Direct care
i. Management of encephalopathy
1) Monitor for signs of increased ICP or neurologic dysfunction. Placement of an ICP monitoring device may be contraindicated in the presence of coag- ulopathy. Provide intubation when appropriate for airway control and hyperventilation.
2) Intervene to decrease serum ammo- nia with administration of neomycin to decrease GI tract ammonia forma- tion and lactulose (Cephulac) to acid- ify colonic flora and promote ammonia elimination. Restrict dietary protein.
ii. To manage hepatorenal syndrome, monitor fluid and electrolyte status and correct electrolyte imbalances. Dialysis may be indicated (hemodialysis or continuous venovenous hemofiltration).
iii. Manage coagulopathy by admini stering blood products (FFP by bolus or continuous infusion, platelets, packed RBCs, and fac- tor VII); IV vitamin K (AquaMEPHYTON) therapy may be required.
iv. Management of portal hypertension 1) Variceal bleeding is treated with
pharmacologic agents (i.e., vasopres- sin [Pitressin], octreotide [Sandostatin], and propranolol [Inderal]), endoscopic band ligation of varices, the Sengstaken−
Blakemore tube (see “Acute Treatment of Esophageal Varices” in “Acute GI Tract Hemorrhage” section), or surgical intervention with a portosystemic shunt, or any combination of these. The use of propranolol (Inderal) is controversial as side effects, including heart block, exacerbation of asthma and altered physiologic response to hypoglyce- mia, may be detrimental. Currently, endoscopic banding or ligation is the most common initial treatment for children with hemorrhagic complica- tions of variceal bleeding (Lirio, 2016).
However, these procedures do not treat the cause of portal hypertension and for many children portosystemic shunting is appropriate.
2) The goal of portosystemic shunts is to redirect portal blood flow into the sys- temic venous circulation, decreasing the
portal venous pressure. Central shunts (portacaval shunt) are created by anas- tomosis of the portal vein to the inferior vena cava. Distal splenorenal shunts are created by anastomosis of the splenic vein to the left renal vein. Nonshunt surgical procedures, including the Sugiura pro- cedure (devascularization of the upper and lower two thirds of greater and lesser curvature of the stomach and ligation of select gastric vessels), are not as success- ful as shunt procedures. Complications of shunting procedures include throm- bosis of the anastomotic vessel, elevated ammonia levels, peptic ulcers, aggravated hepatic failure, and ascites.
3) Management of splenomegaly. A spleen guard is a custom-fitted plastic device to cover and protect the spleen.
Children with spleen guards must avoid contact sports.
4) Management of ascites. Sodium restriction and diuretic therapy (IV furo- semide [Lasix]), or hydrochlorothiazide and spironolactone (Aldactazide) can help to control fluids. Paracentesis may be used when respiratory compromise occurs. It may precipitate fluid shifts.
Complications include infection and hemorrhage.
8. Outcomes. Complications of acute hepatic failure include encephalopathy; cerebral edema, which is a major cause of mortality for children with FHF;
hepatorenal syndrome; and coagulopathies result- ing in GI tract, cerebral, and pulmonary hemor- rhage. Associated mortality for children is as high as 70% to 90%.
LIVER TRANSPLANTATION A. Definition and Etiology
1. Liver transplantation is replacement of the liver that has failed with a segment or whole-cadaver liver or a segment of the liver from a living related or nonrelated donor.
2. Biliary atresia is the most common indication for pediatric liver transplantation. The incidence is one per 10,000 to 19,000 in Europe and North America (Verkade et al., 2016). Biliary atresia is a congenital defect of unknown cause that involves the absence or obstruction of the intrahepatic and extrahepatic
bile ducts. With the development of fibrosis, bile flow is obstructed. Progressive disease with resul- tant fibrosis and eventual cirrhosis occurs.
3. Metabolic Diseases
a. Alpha-1 antitrypsin (α1AT) deficiency is trans- mitted via an autosomal-recessive trait. Only 5%
to 20% of α1AT-deficient children develop liver disease. The disorder involves a deficiency of α1AT, which is a polymorphic glycoprotein syn- thesized by the liver. Liver dysfunction is usu- ally evident as cholestasis during the neonatal period, and cirrhosis develops in later childhood.
Children with α1AT deficiency are at increased risk for developing hepatocellular carcinoma.
b. Tyrosinemia is an autosomal-recessive trait that results in deficiency of fumarylacetoacetate hydrolase (FAH) activity. Children with tyro- sinemia have an increased risk for developing hepatocellular carcinoma.
c. Urea cycle disorders are a group of diseases resulting from the lack of enzymes in the path- way that metabolizes proteins. They are asso- ciated with elevated levels of the metabolite byproduct, ammonia, for which liver transplan- tation is curative.
4. Intrahepatic Cholestasis
a. Progressive familial intrahepatic cholestasis (PFIC) is a group of autosomal-recessive inheritance disorders that constitute a group of three types of disorders (PFIC type 1, 2 [impaired bile salt secretion], and 3 [reduced biliary phospholipid secretion]) with varied clinical characteristics and familial patterns of occurrence (Srivastava, 2014).
It is characterized by a paucity of bile duct devel- opment with the presence of cholestatic jaundice and pruritus. Children with PFIC type 2 have a high incidence of liver tumors and monitoring is recommended from infancy (Srivastava, 2014).
Effective treatment includes nutritional support, surgical biliary diversion, and liver transplanta- tion for many children (Srivastava, 2014).
b. Alagille syndrome (arteriohepatic dysplasia) is an autosomal-dominant trait (Alagille et al., 1987). The syndrome’s characteristics include a broad forehead, indented chin, vertebral defects, pulmonary artery stenosis, and congenital heart disease. Cholestasis may resolve in infancy with recurrence later in childhood.
5. Malignant Disease
a. Hepatoblastoma usually occurs as a mass lesion composed of epithelial cells or a mixture
LIVER TRANSPLANTATION ■ 575
of epithelial and mesenchymal components.
Seventy-five percent of these cases occur before age 3 years. The abdomen may enlarge with the presence of an abdominal mass.
b. Hepatocellular carcinoma is a highly malig- nant tumor characterized by anaplastic hepato- cytes. It has a peak incidence in infancy, with another peak between the ages of 10 and 15 years. Signs and symptoms include abdominal swelling with associated pain and discomfort, fever, nausea, vomiting, weight loss, lethargy, and jaundice.
B. Pathophysiology
Children with ALF and acute-on-chronic liver failure are often candidates for liver transplantation when end-stage liver disease occurs (see “Liver Failure”
section).
C. Clinical Presentation
1. Contraindications to Transplantation. There are no absolute contraindications to liver transplantation.
The presence of metastatic disease or sepsis is a relative contraindication.
2. Pretransplant Considerations
a. Pretransplant considerations involve a medical workup that includes a thorough history and examination, laboratory tests, assessment for evidence of portal hypertension, and assessment of portal vein patency. Family preparation and education are extensive and include education about the pretransplant process, the transplant operation, and care during the posttransplant period.
b. The pediatric end-stage liver disease (PELD) model and model for end-stage liver disease (MELD) are used to generate a score for candi- dates to determine liver allocation. Scores for children 11 years and younger are determined by the PELD model and the scores for children 12 years and older are calculated based on the MELD model. The child’s PELD score is based on age, growth failure, bilirubin level, INR, albu- min, and whether child is younger than 1 year old. The MELD score (which can range from 6 to 40) is based on bilirubin level, INR serum creatinine, and serum sodium (United Network for Organ Sharing [UNOS], 2017). Priority is given to patients who are status 1A (sudden and severe onset ALF and are expected to live hours to a few days) and 1B (very sick, chronically ill pediatric patients <18 years old), and children
with certain diseases (e.g., certain metabolic dis- eases, hepatoblastoma; UNOS, 2017).
D. Patient Care Management
1. Liver transplantation orthotopic and living-re- lated procedures
a. Orthotopic liver transplant (OLTx) refers to the replacement of the diseased liver with the liver or liver segment from a cadaver. A living-related transplant is performed following the dona- tion of part of the liver from a healthy donor.
Increasingly, OLTx is being performed on chil- dren with shared donor grafts (e.g., split grafts).
b. The transplant procedure is divided into three phases: preanhepatic (recipient’s hepa- tectomy), anhepatic (recipient liver has been excised and donor liver is implanted), and neo- hepatic (reperfusion of the new graft). There are vascular anastomoses (including the portal vein and hepatic artery) and a biliary reconstruction is done depending on the recipients’ disease process and size of the native bile duct. Children with biliary atresia or those with small bile ducts require biliary reconstruction to a piece of the intestine.
c. This biliary anastomosis is generally performed via a roux limb and is created as either a hepaticojejunostomy or a choledochoje- junostomy depending on which duct is attached to the jejunum. In children with a disease with a normal biliary system, biliary anastomosis can be completed as an anastomosis between the two bile ducts as a choledocholedocostomy.
2. Postop Nursing Care
a. Promote pulmonary toilet. After resolution of the existing coagulopathies, initiate chest physiotherapy. Evaluate diaphragm function with an US if the child fails extubation twice.
b. Treat hypertension with antihypertensives.
The first-line drug in the immediate postopera- tive period is institution specific; sodium nitro- prusside, sublingual nifedipine (Procardia), or hydralazine are drugs that may be used when necessary.
c. Monitor Jackson−Pratt drainage. Bloody drainage may indicate surgical bleeding. The presence of bile in a surgical drain could indicate a bile leak.
d. Avoid rapid correction of coagulopathies.
Hematocrit is maintained at approximately 30%. Subclinical anticoagulation is used for vessel thrombosis prophylaxis and is initiated
when the PT is less than 17 seconds. Aspirin decreases platelet aggregation. Dipyridamole (Persantine) is a platelet adhesion inhibitor.
Dextran decreases blood viscosity and platelet adhesiveness. Heparin may be used as a prophy- lactic anticoagulant.
e. Other commonly used medications include immunosuppressive therapy (see
“Pharmacology” section earlier in this chapter) and drugs for infection prophylaxis. Broad- spectrum IV antibiotics are given periopera- tively. Co-trimoxazole (Bactrim) is prescribed indefinitely for Pneumocystis carinii, nocar- dia, and toxoplasmosis prophylaxis. Nystatin (Mycostatin) is an antifungal agent used for thrush prophylaxis.
E. Complications and Outcomes