Etiology and pathophysiology

The clinical characteristics of acute pancreatitis follow a similar pattern, despite its varied causes. Damage occurs to the pancreatic acinar cell by an inciting event, leading to premature activation of the digestive enzymes while still within the cell. This inciting event may be infectious, traumatic, metabolic, drug-associated or related to an underlying anatomic anomaly. An inflammatory response occurs to these damaged cells, activating platelets and the complement system. Pro-inflammatory cytokines are released, which include nitric oxide, interleukin-1, platelet activating factor and tumor necrosis factor-a.1 These inflammatory mediators, as well as the release of additional free radicals and other vasoactive substances, damage the gland directly. This can lead to edema, ischemia, necrosis and eventual loss of glandular tissue and atrophy. Systemic shock may occur in severe cases, as demonstrated by tachycardia, hypotension, hypoxia and adult respiratory distress syndrome (ARDS).

While the majority of adult cases of pancreatitis are related to either alcohol consumption or gallstone disease, the causes of pediatric pancreatitis are more varied. In adolescent females, gallstone pancreatitis is not uncommon. However, young children with this disease have often been exposed to a recent trauma, infection, or medication as the inciting event. Recurrent pancreatitis in childhood can be attributed to hereditary pancreatitis, an anatomic variant of the pancreatic or biliary tree, or an underlying systemic or metabolic disorder.

Despite exhaustive investigation, up to 25% of pediatric patients will not have an attributable cause for their acute pancreatitis. The conditions associated with acute and chronic pancreatitis in childhood are outlined in Table 21.1.1-17

Anatomic abnormalities

Congenital defects in the pancreas are rare, but if left uncorrected they can lead to chronic pancreatitis. Pancreatic divisum is the most common anatomic variant.18 It occurs when the dorsal and ventral pancreatic ducts fail to fuse during fetal development, directing flow primarily to the dorsal duct.19 Some believe this variant to be a significant cause of recurrent pancreatitis, which requires either endoscopic or surgical correction. Others think that pancreatic divisum is a variant of normal, and that most people with this anatomy will not experience pancreatitis.

Changes in anatomy which result in duodenal obstruction can also lead to pancreatitis. Reasons for this include strictures, tumors, duplications or diverticula of the duodenum or pancreas, and duodenal hematoma from either accidental or non-accidental trauma (child abuse).

Traumatic causes

Trauma is possibly the most common cause of pancreatitis in childhood, and is probably underestimated. Motor vehicle and bicycle accidents can result in blunt trauma to the pancreas from seat-belts and handlebars. Findings on physical examination consistent with trauma, in the absence of a reliable history, should raise suspicion for child abuse. There are often other associated intraabdominal injuries in cases of significant blunt abdominal trauma. Duodenal hematoma and intestinal perforation are not uncommon.

Infectious causes

A variety of organisms account for a significant number of cases of pancreatitis worldwide, including bacteria, viruses and parasites. The Escherichia coli strain which produces verotoxin and is associated with hemolytic uremic syndrome can also cause pancreatitis. Viruses such as varicella and

Table 21.1 Conditions associated with pancreatitis in the pediatric population (from references 1-17)

Idiopathic

Up to 25% of cases

Anatomic

Ampullary diverticulum Ampullary stenosis Annular pancreas Biliary tract malformations Choledochal cyst Choledochocele

Choledochopancreaticoductal junction anomaly Cholelithiasis

Common bile duct: absence or anomalous insertion

Duodenal obstruction from diverticulum, hematoma, tumor or stricture Duodenal ulcer - perforated Duplication cyst of the common bile duct, duodenum, gastropancreatic area Gastric trichobezoar Pancreatic aplasia Pancreatic divisum

Pancreatic duct: absence or anomalous insertion

Pancreatic dysplasia

Pancreatic heterotopy

Pancreatic hypoplasia

Pancreatic pseudocyst

Pancreatic tumors

Sclerosing cholangitis

Sphincter of Oddi dysfunction

Traumatic

Blunt injury to the abdomen Burns

Contrast from ductal imaging (endoscopic retrograde cholangiopancreatography, percutaneous transhepatic cholangiography) Head trauma

Non-accidental trauma (child abuse) Radiation to the abdomen Surgical trauma Total body cast

Infectious

Ascaris lumbricoides (duct obstruction)

Campylobacter fetus

Clonorchis sinensis (duct obstruction)

Coxsackie B virus

Cryptosporidium

Cytomegalovirus

Echovirus

Enterovirus

Escherichia coli (verotoxin-producing) Hepatitis A virus Hepatitis B virus

Human immunodeficiency virus (HIV)

Influenza A virus

Influenza B virus

Legionnaire's disease

Leptospirosis

Malaria

Measles

Mumps

Mycobacteria

Mycoplasma

Rubella

Rubeola

Toxoplasma

Typhoid fever

Varicella

Yersinia

Hereditary/Metabolic/Systemic ^-Antitrypsin deficiency Anorexia nervosa Autoimmune disease Brain tumor Bulimia

Collagen vascular disease

Congenital partial lipodystrophy

Crohn's disease

Cystic fibrosis

Dehydration

Dermatomyositis

Diabetes mellitus (ketoacidosis)

Glycogen storage disease types la and Ib

Hemochromatosis

Hemolytic-uremic syndrome

Honoch-Schönlein purpura

Hereditary pancreatitis

Hyperalimentation

Hypercalcemia

Hyperlipidemia types I, IV and V

Hyperparathyroidism

Hypertriglyceridemia

Hypothermia

Hypovolemia

Inborn errors of metabolism (organic academia, cytochrome-C oxidase deficiency) Juvenile tropical pancreatitis Kawasaki disease Liver disease Malnutrition

Organic acidemias (homocystinuria, isovaleric acidemia, methylmalonic acidemia, maple syrup urine disease) Periarteritis nodosa Peritonitis

Refeeding syndrome

Renal failure with uremia

Reye's syndrome

Sarcoidosis

Sepsis

Shock

Systemic lupus erythematosus

Transplantation (bone marrow, heart, kidney, liver, pancreas) Ulcerative colitis Vascular diseases Uremia

Wilson's disease influenza B, associated with Reye's syndrome, have also been implicated in causing acute pancreatitis in childhood. Parasites that are more common in developing areas, such as Ascaris and Clonorchis, can migrate into the biliary tree, leading to obstructive jaundice and pancreatitis. Left untreated, this obstruction can lead to severe portal hypertension, liver failure and death.

Children with AIDS are at higher risk for developing acute pancreatitis. One Italian study in symptomatic HIV-infected children demonstrated pancreatic biochemical abnormalities in 15% of the patients.20 However, the elevated enzymes did not correlate with clinical evidence of acute pancreatitis. Although an adult autopsy series showed pancreatic lesions in about 30% of AIDS patients, fewer than 10% had clinical symptoms.21 In children with HIV at autopsy, pancreatic involvement, defined as edema, inflammation, fibrosis, inspissated material and enlarged Langerhan's islets, was frequent.22 However, tumors and involvement of opportunistic infectious was rare. HIV-positive patients can develop elevated enzymes, owing to the HIV infection itself, or owing to other co-infections, such as cytomegalovirus (CMV), Toxoplasma, mycobacte-ria and Cryptosporidium.17 Many of the pharmacological agents used to inhibit HIV can cause pancreatitis (see Medications). Hyperamylasemia without pancreatitis can occur from renal failure, AIDS-associated nephropathy, or salivary hyper-amylasemia from parotid gland disease due to HIV.23 Kaposi's sarcoma and lymphoma can also affect the pancreas.24

Hereditary, metabolic and systemic diseases

The most common inherited disease of the exocrine pancreas is thought to be cystic fibrosis (CF).25 This autosomal recessive disease is caused by mutations in the CF transmembrane conductance regulator gene (CFTR). CFTR is located on the apical membrane of the epithelial cells that line the pancreatic ducts. The transporter promotes dilution and alkalinization of the pancreatic secretions and they flow through the ductular network. CF may be one of the most common causes of pancreatitis in childhood, but pancreatitis itself is a rare presenting feature of CF.26 It is believed that up to 2% of individuals with CF experience pancreatitis as a result of ductal plugging due to mutant CFTR.27 CF is the only known hereditary disease in which there can be both pancreatitis, and exocrine insufficiency in the absence of pancreatic inflammation.28 However, those patients with CF and pancreatic insufficiency do not develop acute relapsing pancreatitis, presumably because of the loss of functional acinar tissue.7 Even in the absence of lung disease, there appears to be a strong correlation between specific CFTR mutations and idiopathic and chronic pancreatitis.29-31 Patients with recurrent pancreatitis without an obvious cause should be screened for CF with a sweat chloride test. CFTR mutational analysis is also commercially available. The role of CFTR in pancreatitis and other diseases of the pancreas is the subject of ongoing research.

The second most common cause of chronic pancreatitis in childhood is believed to be hereditary pancreatitis.32 The gene defects were reported in 1996,33 and help explain some of the patho-physiology of the non-hereditary forms of both acute and chronic pancreatitis.34,35 The two known types of hereditary pancreatitis are clinically similar, and involve different mutations within the same gene. Both types are autosomal dominant with 80% penetrance.36 The majority of affected patients report symptoms before the age of 15 years, with some symptomatic even before the age of 5 years. The gene involved is located on chromosome 7q35, and codes for cationic trypsinogen (PRSS1). Both mutations result in a form of trypsin that resists degradation by mesotrypsin and enzyme Y,26 allowing trypsinogen to become activated to trypsin within the pancreas instead of within the duodenum. This leads to uncontrolled activation of other pancreatic enzymes within the acinar cell, resulting in autodigestion and inflammation. The attacks of acute pancreatitis are remarkably only intermittent. It is thought that this uncontrolled activation of other enzymes occurs only when trypsin exceeds the capacity of pancreatic secretory trypsin inhibitor, the 'secondary brake' within the pancreatic gland. Identification of those with hereditary pancreatitis is critical, as affected patients are at increased risk for pseudocysts, pancreatic adenocarcinoma, and exocrine and endocrine failure.37

Since the discovery that hereditary pancreatitis can be caused by mutations in PRSS1, researchers have been searching for other potential candidate genes that may predispose patients to chronic pancreatitis. Given that the proposed mechanism for pancreatitis with PRSS1 mutations is decreased inactivation, one candidate gene is that encoding for pancreatic secretory trypsin inhibitor or serine protease inhibitor, Kazal type 1 (SPINK1 ).38 SPINK1 mutations have been reported in a wide phenotype of conditions, including familial, hereditary, tropical and idiopathic chronic pancreatitis.39-42 Whether or not SPINK1 mutations modify an already underlying genetic disease has yet to be elucidated.38

Pancreatitis has been a reported complication in children who have received heart, kidney, liver, pancreas or bone marrow transplants.8 Following liver transplantation, it can be life-threatening, and is associated with a higher risk for infectious peritonitis and emergency retransplantation.9 As with autoimmune and collagen-vascular diseases, it is difficult to distinguish between the contributions of medications versus the primary disease process to the development of the pancreatitis.

Medications

Numerous medications and naturally occurring toxins have been reported as a cause of pancreatitis (Table 21.2).^.e.17.23.43-45 Often, however, the

Table 21.2 Drugs and toxins associated with pancreatitis (from references 1-4,6,17,23,43-45)

Acetaminophen overdose

Meprobamate

Alcohol

Mercaptopurine

Amphetamines

Mesalamine

Anticoagulants

Methotrexate

Asparaginase

Methyldopa

Azathioprine

Metronidazole

Boric acid

Non-steroidal anti-inflammatory drugs

Bumetanide

Nitrofurantoin

Calcium

Octreotide

Carbamazepine

Opiates

Chlorthalidone

Oxyphenbutazone

Cholestyramine

Organophosphates

Cimetidine

Paromomycin

Cisplatin

Penicillin

Clonidine

Pentamidine

Clozapine

Phenformin

Corticosteroids

Piroxicam

Corticotropin

Procainamide

Cyclophosphamide

Propoxyphene

Cyproheptadine

Propylthiouracil

Cytarabine

Ranitidine

Cytosine arabinoside

Rifampin

Diazoxide

Salicylates

Didanosine

Scorpion venom

Dideoxycinosine

Spider venom

Dideoxycytidine

Sulfasalazine

Diphenoxylate

Sulfonamides

Enalapril

Sulindac

Erythromycin

Tetracycline

Estrogen

Thiazides

Ethacrynic acid

Tretinoin

Furadantin

Trimethoprim-sulfamethoxazole

Furosemide

Valproic acid

Heroin

Vincristine

Histamine

Vitamin D

Indomethacin

Isoniazid

Lamivudine

relationship between drugs and pancreatitis is more of association than causation. Classes of medications most likely to cause pancreatitis include antibiotics (erythromycin, metronidazole, nitrofurantoin, penicillin, rifampin), anticonvul-sants (carmbamazepine, valproic acid), antihypertensives (clonidine, diazoxide, enalapril), anti-inflammatories (corticosteroids, ibuprofen, indomethacin, sulfasalazine and acetaminophen when overdosed) and antineoplastic agents (asparaginase, azathioprine, mercaptopurine, cyclophosphamide, vincristine). Most of the drugs mentioned in this chapter have a proposed but unproven pathophysiology, and very few documented an established causal relationship to pancreatitis.

Clinical signs and symptoms

In the pediatric population, the classic signs of acute pancreatitis include nausea, vomiting, anorexia and abdominal pain. The pain is classically located in the epigastrium, with radiation to the back. However, the pain could also be located in the periumbilical region, right upper quadrant or lower chest.46,47 Eating usually exacerbates the abdominal discomfort and emesis, which may progress to biliousness. In the review of systems, the physician should inquire about rashes, diarrhea, joint pain and other signs of vasculitis. A family history of pancreatitis should raise suspicion for hereditary and metabolic diseases (see Table 21.1).

More common causes of acute abdominal pain in childhood may be differentiated from pancreatitis by a thorough physical examination. If fever is present, it is usually of low grade. However, tachycardia and hypotension may be present early in the course of the disease. Tachypnea with hypoxemia can indicate developing pulmonary edema. The child may be icteric and ill-appearing, with a distended abdomen and decreased bowel sounds, owing to an ileus, ascites or a mass from a pancreatic phlegmon or pseudocyst. While lying supine on the examination table, the patient may experience some relief of pain when the knees are drawn up to a flexed trunk. In advanced disease, where there has been pancreatic hemorrhage or necrosis, two signs may be present: Grey Turner sign, which is a blue discoloration of the flank; and Cullen's sign, where there is blue discoloration around the pancreas. The child should be examined for physical findings of child abuse, especially if there is an unclear history of trauma to the abdomen.

Evaluation Laboratory tests

Routine blood tests can usually differentiate acute pancreatitis from the more common causes of abdominal pain in childhood. A complete blood cell count with white cell differential usually demonstrates leukocytosis with a left shift, and hemoconcentration from dehydration. Frequent findings in a routine chemistry panel include hyperglycemia and elevated levels of total biliru-bin, alanine aminotransferase and aspartate aminotransferase. Anemia, azotemia, hypoalbu-minemia, hypocalcemia and an elevated lactate dehydrogenase level suggest advanced disease with hemorrhage and pancreatic damage.

The most frequently used laboratory tests to screen for acute pancreatitis are serum amylase and lipase. Amylase levels begin to rise within 2-12h, and peak at 12-72 h after the initial pancreatic insult.48 However, an isolated serum amylase level has a relatively low sensitivity (75-92%) and specificity (20-60%).5 This is because normal amylase levels may be seen with pancreatitis, and hyperamylasemia can result from many diseases that are not of pancreatic origin (Table 21.3).5,23,48,49 If the amylase level is three to six times above the upper limit of normal for that laboratory, the specificity increases for pancreatitis, but at the expense of sensitivity.5 More discriminatory are the measurements of serum isoamylase levels, which differentiate between enzymes of salivary and pancreatic origin. Isoamylase levels should be determined if parotitis from a viral infection is suspected (such as with HIV), in the presence of some cancers, and if ovarian disease is present (Table 21.3).

After serum amylase, serum lipase is the test most frequently used to confirm acute pancreatitis. Lipase levels begin to increase 4-8h after the onset of symptoms, and also peak at about 24h.50 However, lipase levels remain elevated for a longer period of time than amylase levels, decreasing over

Table 21.3 Conditions other than pancreatitis associated with elevated serum amylase (from

references 5,23,48,49)

Abdominal aortic aneurysm (pancreatic amylase

Lung cancer (salivary amylase elevation only)

elevation only)

Macroamylasemia

Alcoholism

Opiates

Anorexia nervosa (salivary amylase elevation only)

Ovarian cyst (salivary amylase elevation only)

Appendicitis (pancreatic amylase elevation only)

Ovarian tumor (salivary amylase elevation only)

Biliary duct obstruction (parasite, stone, tumor)

Pancreatic duct obstruction (parasite, stone, tumor)

(pancreatic amylase elevation only)

(pancreatic amylase elevation only)

Biliary tract disease (pancreatic amylase elevation

Pancreatic tumor (pancreatic amylase elevation

only)

only)

Bulimia (salivary amylase elevation only)

Parotitis (salivary amylase elevation only)

Burns

Peptic ulcer - perforated (pancreatic amylase

Cardiopulmonary bypass

elevation only)

Choledocholithiasis (pancreatic amylase elevation

Peritonitis (pancreatic amylase elevation only)

only)

Pneumonia (salivary amylase elevation only)

Cirrhosis

Prostate tumors (salivary amylase elevation only)

Cystic fibrosis

Renal insufficiency

Diabetic ketoacidosis

Renal transplant

Drugs

Ruptured ectopic pregnancy

Hepatitis

Salivary duct obstruction (salivary amylase

Heroin addiction

elevation only)

Intestinal infarction (pancreatic amylase elevation

Salpingitis (salivary amylase elevation only)

only)

Trauma (to the head or abdomen)

Intestinal obstruction (pancreatic amylase elevation

Viral infections (mumps) (salivary amylase elevation

only)

only)

Intestinal perforation (pancreatic amylase elevation

only)

8-14 days. Serum lipase levels have a reported clinical sensitivity of 86-100% and specificity of 50-99%.51 If the serum lipase level is greater than three times the upper limit of normal for that laboratory, sensitivity and specificity can be increased to 99-100%.5 However, a significantly elevated lipase level, in the presence of a normal amylase level, has been reported in esophagitis, hyper-triglyceridemia, renal insufficiency, acute cholecystitis and non-pancreatic sources of lipolytic enzymes due to malignant tumors.52

Clinical sensitivity for the diagnosis of acute pancreatitis increases to 94% by using serum amylase and lipase level determinations in parallel.5,52 It is important to note, however, that the degrees of elevation of the amylase and lipase levels in the plasma in no way reflect the severity of the pancreatic disease process itself. There are serum enzymes more sensitive than amylase which do correlate with disease severity, such as plasma immunoreactive cationic trypsin, pancreatic elastase I and phospholipase A2.5 However, these tests are not readily available outside research centers.

The diagnosis of chronic pancreatitis relies not only on clinical and radiographic findings (see next section), but also on tests of pancreatic func-tion.53 The 'gold standard' for the assessment of pancreatic function involves direct testing for pancreatic insufficiency. This is accomplished via the administration of intravenous secretin or cholecystokinin, and measuring the levels of bicarbonate and pancreatic enzymes from the pancreatic ductal secretions. To perform this in a pedi-atric patient requires endoscopic intubation of the duodenum, with accurate placement of a catheter to collect the secretions, under appropriate anesthesia. If performed correctly, the sensitivity and specificity of this procedure for the diagnosis of chronic pancreatitis ranges from 90 to 100%.54

Because of the challenges in performing and interpreting these examinations, they are usually available only in tertiary centers.

Although not as accurate, non-invasive tests of pancreatic function are more readily available. Chronic pancreatitis can be demonstrated by decreased enzymes in the blood (amylase, lipase, isoamylase, immunoreactive trypsinogen) or stool (trypsin, pancreatic elastase I), or increased amounts of malabsorbed food products (primarily fat). A recent pediatric study showed that testing for fecal pancreatic elastase I compared favorably to the secretin-pancreozymin test, reporting 100% sensitivity and 96% specificity for pancreatic insufficiency due to CF. However, because of the generally poor negative predictive value of these tests, chronic pancreatitis cannot be excluded with certainty. False-positive results can be seen with bacterial overgrowth and other mucosal diseases of the small bowel.

Radiographic studies

Although the study of choice to delineate pancreatic changes is abdominal ultrasonography,55 a plain abdominal radiograph (kidney, ureters and bladder; KUB) may demonstrate anomalies. Acute pancreatitis may result in an ileus, with either colonic distension or a 'sentinel' loop of dilated small bowel. Obscured psoas margins or a radiolu-

Echogenicity Pancreas Ultrasound
Figure 21.2 Ultrasound demonstrating acute pancreatitis in a 9-year-old HIV-positive girl. The head and the body of the pancreas are decreased in echogenicity and diffusely enlarged.

cent 'halo' around the left kidney are also suggestive of pancreatitis. Calcifications can be seen in the area of the pancreatic parenchyma and ductal system with chronic pancreatitis (Figure 21.1).

Changes in pancreatic size, contour and texture are best appreciated with ultrasound. This modality is also excellent at identifying ascites, abscesses, pseudocysts, dilated ducts and gallstone disease (Figures 21.2-21.5).

Computed tomography (CT), with oral and intravenous contrast, is useful in managing the complications of long-standing pancreatitis.55 CT can provide more accurate guidance in the aspiration and drainage of an abscess, phlegmon or pseudo-cyst. Prior to any type of surgical intervention, such as necrostomy (surgical debridement for necrosis), CT may be utilized for further definition of the peripancreatic anatomy, and to rule out other complications, such as a portal vein thrombosis (Figures 21.6-21.15).

KUB, ultrasound and CT are not adequate in clinical circumstances under which a detailed anatomy of the pancreatic and biliary tree is necessary, such as in chronic pancreatitis and recurrent attacks of acute pancreatitis. Cholangiopancreatography may be accomplished by endoscopic retrograde cholan-giopancreatography (ERCP), magnetic resonance cholangiopancreatography (MRCP), or via a direct cholangiogram performed either percutaneously or

Pancreatitis Ultrasound
Figure 21.3 Ultrasound demonstrating sludge in the gallbladder of the same patient as in Figure 21.2. There is no gallbladder wall thickening or pericholecystic fluid. No calculi were identified, but they could be obscured by the sludge.
Ultrasound Gallbladder With SludgeSeptic Shock Pathophysiology

Figure 21.4 Ultrasound demonstrating biliary ductal dilatation in a 7-year-old girl with chronic pancreatitis. The common bile duct is abnormally dilated, measuring 1.2 cm in diameter. This fusiform enlargement of the common bile duct, proximal to its bifurcation just at the hilus of the liver, is suggestive of a choledochal cyst.

Figure 21.5 Ultrasound of a pseudocyst in an 18-year-old female with chronic pancreatitis after a severe upper gastrointestinal bleed, respiratory failure and septic shock The pancreas was normal in echogenicity, but a pseudocyst was seen in the body measuring 2.8x1.9x1 cm.

4x3 Sized Ovarian Cyst
Figure 21.6 Computed tomography scan of acute pancreatitis in the abdomen of a 4-year-old boy. Fluid collections are seen near the pancreatic head and tail (arrows), consistent with inflammatory changes. There are areas of hypodensity within the pancreas, representative of acute pancreatitis.
Lymphoma Pancreas Head

Figure 21.7 Computed tomography scan demonstrating biliary ductal dilatation in the abdomen of the patient in Figure 21.4. There is extrahepatic bile duct and pancreatic duct dilatation (arrows). The pancreas has a normal density. Intrahepatic ductal dilatation was seen on other sections. The differential diagnosis in this patient includes choledochal cyst, Caroli's disease and sclerosing cholangitis.

Figure 21.7 Computed tomography scan demonstrating biliary ductal dilatation in the abdomen of the patient in Figure 21.4. There is extrahepatic bile duct and pancreatic duct dilatation (arrows). The pancreas has a normal density. Intrahepatic ductal dilatation was seen on other sections. The differential diagnosis in this patient includes choledochal cyst, Caroli's disease and sclerosing cholangitis.

Chest Pathophysiology Equipment ImageRadiographics Varices

Figure 21.9 Computed tomography scan of an atrophic pancreas in the same patient as in Figure 21.8, 1 year later. The pancreas is essentially absent, with only minimal tissue identified in the tail. A 4x3.6x3.8cm cystic mass is present in the region of the former body of the pancreas, consistent with a pseudocyst (arrow). This patient went on to develop cirrhosis with portal hypertension due to portal vein thrombosis. Esophageal, gastric, splenic and retroperitoneal varices were seen on other sections. Recanalization of the portal and umbilical veins was also visualized. Pancreatic atrophy rendered this patient dependent upon insulin and pancreatic enzyme replacements.

Figure 21.8 Computed tomography scan of the abdomen of a 16-year-old morbidly obese male with chronic pancreatitis. The pancreas demonstrates enhancements with focal lesions. The head was poorly visualized. The body and tail are enlarged, consistent with chronic pancreatitis. Endoscopic retrograde cholangiopancreatography demonstrated pancreatic divisum.

Figure 21.8 Computed tomography scan of the abdomen of a 16-year-old morbidly obese male with chronic pancreatitis. The pancreas demonstrates enhancements with focal lesions. The head was poorly visualized. The body and tail are enlarged, consistent with chronic pancreatitis. Endoscopic retrograde cholangiopancreatography demonstrated pancreatic divisum.

Calcific Chronic Pancreatitis

Figure 21.10 Computed tomography (CT) scan of calcified chronic pancreatitis in the abdomen of a 14-year-old obese girl. The patient had complained of abdominal pain with nausea and vomiting for several months. She was found to have a hiatal hernia, and underwent laparoscopic fundoplication. The abdominal pain persisted, despite a repeat of her 'slipped' fundoplication, and this CT scan was ordered. There is fatty atrophy of the pancreas with multiple punctuate and small calcifications consistent with chronic pancreatitis. The pancreatic duct is dilated, measuring 1.2 cm at the uncinate process. There is a calcification in the duct near the ampulla of Vater (arrow), which appears to be lodged in the common bile duct, causing proximal dilatation. There are several small pseudocysts in the upper abdomen. The largest is in the lesser sac just inferior to the stomach, measuring 3x4x 3 cm, with inflammation present. This patient remains dependent upon parenteral nutrition.

Figure 21.9 Computed tomography scan of an atrophic pancreas in the same patient as in Figure 21.8, 1 year later. The pancreas is essentially absent, with only minimal tissue identified in the tail. A 4x3.6x3.8cm cystic mass is present in the region of the former body of the pancreas, consistent with a pseudocyst (arrow). This patient went on to develop cirrhosis with portal hypertension due to portal vein thrombosis. Esophageal, gastric, splenic and retroperitoneal varices were seen on other sections. Recanalization of the portal and umbilical veins was also visualized. Pancreatic atrophy rendered this patient dependent upon insulin and pancreatic enzyme replacements.

Autoimmune Pancreatic Around Main Vein

Figure 21.11 Computed tomography scan of the abdomen in an 11-year-old girl with chronic pancreatitis undergoing treatment for acute lymphoblastic leukemia. A massive 19x5.5x8.5 cm pseudocyst is seen in the left upper quadrant (arrows). There is edema and necrosis within the pancreatic tissue, and a smaller pseudocyst within the pancreatic head. There is free fluid within the abdomen and stranding within the mesentery of the left upper quadrant consistent with chronic inflammation. The liver shows fatty infiltration with a normal gallbladder. This pseudocyst resolved without surgical intervention.

Figure 21.11 Computed tomography scan of the abdomen in an 11-year-old girl with chronic pancreatitis undergoing treatment for acute lymphoblastic leukemia. A massive 19x5.5x8.5 cm pseudocyst is seen in the left upper quadrant (arrows). There is edema and necrosis within the pancreatic tissue, and a smaller pseudocyst within the pancreatic head. There is free fluid within the abdomen and stranding within the mesentery of the left upper quadrant consistent with chronic inflammation. The liver shows fatty infiltration with a normal gallbladder. This pseudocyst resolved without surgical intervention.

Gallbladder Focal Fatty Infiltration

Figure 21.12 Computed tomography scan of the abdomen in a 10-year-old girl with end-stage renal disease, found to have bloody drainage from her peritoneal dialysis catheter. There are diffuse inflammatory changes around the pancreas which extend up and around the lateral aspect of the stomach. The pancreas is low in attenuation and heterogeneous, suggestive of necrosis. There are multiple fluid collections in the region of the tail of the pancreas. There is a small amount of pericholecystic fluid surrounding the anterior wall of the gallbladder (arrow). Other sections delineated superior mesenteric and portal vein thrombosis. The kidneys did not concentrate or excrete contrast, consistent with the patient's renal failure.

Renal Halo Sign Acute Pancreatitis

Figure 21.13 Computed tomography scan of chronic pancreatitis with cystic changes in the same patient as in Figure 21.12, taken 5 months later, demonstrating pseudocyst formation with extensive cystic changes within the body and tail of the pancreas. Owing to an intracra-nial bleed, the patient's nutritional status was maintained on an elemental liquid diet (appropriate for a patient with renal failure) via a gastrostomy tube.

Figure 21.12 Computed tomography scan of the abdomen in a 10-year-old girl with end-stage renal disease, found to have bloody drainage from her peritoneal dialysis catheter. There are diffuse inflammatory changes around the pancreas which extend up and around the lateral aspect of the stomach. The pancreas is low in attenuation and heterogeneous, suggestive of necrosis. There are multiple fluid collections in the region of the tail of the pancreas. There is a small amount of pericholecystic fluid surrounding the anterior wall of the gallbladder (arrow). Other sections delineated superior mesenteric and portal vein thrombosis. The kidneys did not concentrate or excrete contrast, consistent with the patient's renal failure.

Figure 21.13 Computed tomography scan of chronic pancreatitis with cystic changes in the same patient as in Figure 21.12, taken 5 months later, demonstrating pseudocyst formation with extensive cystic changes within the body and tail of the pancreas. Owing to an intracra-nial bleed, the patient's nutritional status was maintained on an elemental liquid diet (appropriate for a patient with renal failure) via a gastrostomy tube.

Pancreatic Stricture

Figure 21.15 Repeat computed tomography scan of the abdomen of the patient in Figure 21.14, performed 8 months later. There are areas of necrosis within the pancreatic body and tail (arrows). A pseudocyst is present at the pancreatic tail near the splenic hilum. Bones demonstrate osteopenia, also consistent with high-dose steroids.

Figure 21.14 Computed tomography scan of the abdomen of a teenage boy with recurrent pancreatitis. He had received high-dose steroids for treatment of non-Hodgkin's lymphoma. The pancreas is edematous and there are multiple, small pseudocysts (arrows) which have enhancing rims. These findings are consistent with severe hemorrhagic pancreatitis. The liver is enlarged with low attenuation consistent with fatty infiltration.

Figure 21.15 Repeat computed tomography scan of the abdomen of the patient in Figure 21.14, performed 8 months later. There are areas of necrosis within the pancreatic body and tail (arrows). A pseudocyst is present at the pancreatic tail near the splenic hilum. Bones demonstrate osteopenia, also consistent with high-dose steroids.

Mri Pancreas Tail

Figure 21.16 Magnetic resonance imaging (MRI) demonstrating pancreatitis with ductal dilatation in a previously healthy 16-year-old female with a 1-month history of nausea and epigastric pain after meals. Initial ultrasound examination revealed pancreatic edema and ductal dilatation. The patient's amylase and lipase levels continued to rise, despite the pancreatic rest. MRI revealed a dilated pancreatic duct (arrow) with increased signal intensity at the junction of the body and the tail, consistent with edema.

Figure 21.16 Magnetic resonance imaging (MRI) demonstrating pancreatitis with ductal dilatation in a previously healthy 16-year-old female with a 1-month history of nausea and epigastric pain after meals. Initial ultrasound examination revealed pancreatic edema and ductal dilatation. The patient's amylase and lipase levels continued to rise, despite the pancreatic rest. MRI revealed a dilated pancreatic duct (arrow) with increased signal intensity at the junction of the body and the tail, consistent with edema.

intraoperatively. These studies may reveal cholelithiasis, anatomic malformations or biliary strictures.

ERCP is the study of choice to visualize anatomic malformations, such as pancreas divisum or anomalous pancreaticobiliary duct junction.15,18 ERCP may be difficult in very small children, owing to the large diameter of the endoscope required. ERCP, as opposed to MRCP, has the added benefit of being a therapeutic modality. Sphincterotomy, stent placement and stone removal can all be performed at the time of the initial diagnostic eval-uation.56 Sphincter of Oddi manometry to look for elevated basal pressures consistent with dysfunction can also be useful, as these patients may benefit from endoscopic sphincterotomy.15 These procedures should be undertaken only at centers that have significant experience both in performing the studies and in managing severe cases of childhood pancreatitis. A pediatric surgeon should be available at the center, as complications of ERCP can include duct perforation or a worsening of the pancreatitis from the contrast, leading to abscess, phlegmon or pseudocyst formation requiring surgical drainage. However, when performed by experienced endoscopists, therapeu-

Phlegmon Formation

Figure 21.17 Magnetic resonance cholangiopancreatography demonstrating pancreatitis with ductal dilatation in the same patient as in Figure 21.16. Dilatation of the pancreatic duct (arrow), common bile duct, and the right and left main hepatic ducts (arrowheads) are seen, consistent with an impacted stone at the ampulla of Vater.

Figure 21.17 Magnetic resonance cholangiopancreatography demonstrating pancreatitis with ductal dilatation in the same patient as in Figure 21.16. Dilatation of the pancreatic duct (arrow), common bile duct, and the right and left main hepatic ducts (arrowheads) are seen, consistent with an impacted stone at the ampulla of Vater.

tic ERCP in selected pediatric patients has been reported to have a lower rate of complications than in the adult population.57

MRCP should be reserved for patients who are too small or too clinically unstable to receive general anesthesia to undergo ERCP. This modality has proved useful in determining the presence of pancreaticobiliary disease, the level of biliary obstruction, and the presence of malignancy or bile duct calculi (Figures 21.16 and 21.17).58,59 The quality of the MRCP images depend upon the ability of the patient to remain still (which may require light sedation in small children), and whether the MRCP equipment and computer programs are regularly updated. Interpretation also requires a skilled radiologist familiar with the various potential pancreaticobiliary tree anomalies.

If an anatomic variant is suspected, and ERCP or MRCP are not possible, the next appropriate step is direct imaging of the pancreaticobiliary system with contrast, performed either percutaneously or intraoperatively. A percutaneous cholangiogram may be performed in the presence of dilated ducts, or through a biliary drain. Biliary drains may have been placed postoperatively from pancreatic surgical debridement or orthotopic liver transplant. This type of study requires a skilled interventional radiologist. In the absence of dilated ducts or a biliary drain, transduodenal exploration with intraoperative pancreatography should be performed. Like ERCP, intraoperative imaging can likewise be a therapeutic modality at the time of initial diagnostic evaluation. If minor or major stenosis of papillae is found, surgical sphincteroplasty can be performed concurrently.60

Delicious Diabetic Recipes

Delicious Diabetic Recipes

This brilliant guide will teach you how to cook all those delicious recipes for people who have diabetes.

Get My Free Ebook


Responses

Post a comment