17.3 Pancreatitis and Bowel Obstruction

CPHON TCO V.B.1–2 tests two gastrointestinal emergencies that are not typhlitis and not ordinary Domain IV constipation: pancreatitis and bowel obstruction. Recognition, first actions, and monitoring differ, but both start with nothing by mouth (NPO), intravenous access, and a call that does not wait for the next clinic day.

A 5-year-old eight days after pegaspargase who points to the epigastrium and leans forward, and an 8-year-old with Burkitt lymphoma who vomits bile and has not passed stool or flatus, are the paired pictures.

Pancreatitis: asparaginase first, then the rest of the list

Asparaginase products—pegaspargase, native asparaginase, and Erwinia-derived crisantaspase—are the classic pediatric oncology trigger. They deplete asparagine and injure the pancreas. Pancreatitis can follow the first dose or a later dose and can declare days to a couple of weeks after pegaspargase, not only during the infusion chair time. Corticosteroids add risk and add hyperglycemia. Gallbladder sludge and stones (asparaginase, prolonged parenteral nutrition, ceftriaxone, obesity) can obstruct the biliary tree and cause gallstone pancreatitis.

Recognition:

• Abdominal pain that is epigastric or periumbilical and radiates to the back. The child may sit forward or refuse to lie flat. A preschooler may only cry and draw the knees up; ask where it hurts, but do not require an adult-style radiation history.
• Nausea and vomiting, anorexia, sometimes low-grade fever.
• Elevated lipase (preferred) and amylase. A lipase several times the upper limit of normal plus the clinical picture is the laboratory confirmation the team uses; do not invent a single ONCC cutoff unit.
• Imaging—ultrasound for sludge and biliary dilation; CT if the diagnosis is unclear or complications are suspected—supports but does not delay resuscitation of a child in pain.

First actions:

• NPO. Do not offer a fatty test meal to see if the pancreas can handle it.
• Intravenous fluids—generous isotonic resuscitation as ordered; pancreatitis third-spaces fluid into the retroperitoneum.
• Pain control. Opioids (morphine, hydromorphone) are used as ordered; do not withhold analgesia because of an outdated sphincter-of-Oddi myth.
• Nasogastric suction if there is ileus and persistent vomiting.
• Hold further asparaginase until the oncology team and protocol decide whether to omit, delay, or switch products. Do not hang the next pegaspargase because the lipase will come down.
• Glucose monitoring and insulin as ordered. Asparaginase plus steroids produce hyperglycemia even without pancreatitis; pancreatitis makes it worse. Polyuria in this child is glucose until proven otherwise, not automatically diabetes insipidus from the metabolic-emergency chapter.
• Intensive care for shock, hypocalcemia with tetany, oliguria, or respiratory failure.

Walk the ALL induction evening. Pegaspargase was given eight days ago. Dexamethasone is still on. The 5-year-old vomits bile-tinged fluid, holds the upper belly, and will not lie flat. Fingerstick glucose is 320 mg/dL. This is pancreatitis plus steroid-asparaginase hyperglycemia until lipase says otherwise. NPO, fluids, pain medicine, insulin as ordered, hold the enzyme. Do not attribute back-radiating pain after pegaspargase to vincristine constipation without a lipase. Do not restart asparaginase from the chair without the protocol decision.

Monitoring: pain scores, vital signs, intake and output, glucose, calcium, and clinical exam. Pseudocyst is a delayed fluid collection—days to weeks later—that can cause recurrent pain, early satiety, or infection. Recurrence of pain after the child was improving is not a reason to restart snacks without a team look. Nutrition moves from NPO to enteral feeding when the team says the gut is ready; parenteral nutrition is for prolonged inability to feed, not a first-hour trophy. Severe pancreatitis can look like sepsis; if perfusion fails, treat shock and keep the pancreatic diagnosis on the board rather than dropping it for FN alone.

Bowel obstruction: vincristine ileus versus mechanical block

Bowel obstruction in pediatric oncology is either functional ileus or mechanical blockage. Vincristine autonomic neuropathy is the classic functional path: distension, hypoactive sounds, vomiting, and absent stool after a vinca dose, often on top of opioids. Prevention is a bowel regimen (polyethylene glycol, senna as ordered) the day vincristine starts. Domain IV already said this; here the failure is an emergency. Hold further vincristine when ileus is significant so the protocol can reduce or delay.

Mechanical causes: bulky tumor (especially non-Hodgkin lymphoma or Burkitt abdominal disease, neuroblastoma), adhesions after laparotomy, and intussusception with a lymphomatous lead point. Bilious emesis, no stool or flatus, and distension are obstruction until proven otherwise. Intermittent colicky pain in lymphoma raises intussusception even before currant-jelly stool, which is late. A sausage-like abdominal mass is not constipation.

First actions for either picture:

• NPO.
• Intravenous fluids and electrolyte replacement.
• NG decompression.
• Serial abdominal exams.
• Imaging (plain films for air-fluid levels; contrast studies or CT as the team directs) to look for a transition point.
• Surgical consult. Do not wait until midnight rigidity to call. Vincristine ileus is often medical; mechanical obstruction and ischemic bowel are not.

Distinguishing: ileus is functional, often hypoactive, without a transition point. Mechanical obstruction may start with high-pitched rushes, has a transition point, and includes tumor, adhesions, and intussusception. Do not give stimulant laxatives or enemas when mechanical obstruction or neutropenia with an acute abdomen is in play. Do not feed to stimulate motility in a child with bilious emesis. Do not send the Burkitt belly home with juice and a wait-and-see stool chart.

A 10-year-old on ALL with vincristine two days ago, a quietly distended abdomen, and no peritoneal signs is ileus until imaging excludes a block—NPO, NG, hold the vinca, continue the bowel regimen when the team says the gut may move. An 8-year-old with NHL, intermittent screaming, bilious emesis, and a sausage-like mass is intussusception until surgery and oncology say otherwise. Those are not the same order set. After recovery from vincristine ileus, restart polyethylene glycol before the next vinca, not after three more days without stool.

Typhlitis remains on the differential when the child is profoundly neutropenic with fever and RLQ findings; obstruction without neutropenia and without fever still gets NPO and an NG tube, not a typhlitis antibiotic bundle as the only thought. Pancreatitis pain radiates to the back after asparaginase; obstruction pain is distension and failed passage of stool. Draw the lipase when the enzyme is on the medication list. Place the NG tube when the emesis is green.

The CPHON product is a lipase drawn before the next pegaspargase, an NG tube in a child with green emesis, a surgeon who heard about the Burkitt belly before perforation, and a polyethylene glycol order that started with the first vincristine—not a parent told to try juice and wait.