e151CHAPTER 136 Board Review Questions serve as a guide for future dilations if they become necessary Some surgeons have advocated early placement of gastrostomies and esophageal stents in patients wi[.]
CHAPTER 136 Board Review Questions serve as a guide for future dilations if they become necessary Some surgeons have advocated early placement of gastrostomies and esophageal stents in patients with third-degree burns Which of the following types of foreign body lodged in a child’s esophagus warrants immediate removal (less than hours after ingestion)? A All foreign bodies B Button batteries C Metallic toys D Wooden toys Preferred response: B Rationale Children can swallow a variety of metallic, wooden, or plastic foreign bodies in a myriad of shapes and sizes All that are lodged in the esophagus require urgent removal (within 24 hours) Even more urgent endoscopic retrieval is required for button batteries or pennies minted after 1983 that are lodged in the esophagus because both are caustic to esophageal mucosa and may cause damage within to hours The preponderance of evidence suggests that once a battery has escaped the esophagus, complications from an unretrieved battery are rare Similarly, pennies minted after 1983 are predominantly zinc based and can be nearly as caustic within the esophagus as button batteries No published epidemiologic studies are available on which to base the approach to zinc-based pennies within the stomach or small intestine 10 Which of the following is a frequent associated finding in patients with a gastric ulcer? A Delayed gastric emptying B Gastroesophageal reflux C Hyperchlorhydria D Infection with Helicobacter pylori Preferred response: A Rationale Most patients with gastric ulcers are hypochlorhydric rather than hyperchlorhydric because exposure to detergents or toxins such as nonsteroidal antiinflammatory drugs, pepsin, bile salts, or ethanol erodes the gastric barrier to back diffusion A second consistent finding in patients with gastric ulcers is delayed gastric emptying, which may be an epiphenomenon or central to the pathogenesis of ulcers The association between Helicobacter pylori infection and both chronic gastritis and duodenal ulcer is well established, but the role of H pylori in the pathogenesis of gastric ulceration remains somewhat speculative 11 A 10-year-old child with hyperlipidemia type I presents with severe left upper quadrant abdominal pain radiating to the back Serum lipase and amylase are significantly elevated What abnormality is commonly encountered in this case scenario? A Hyperkalemia B Hypermagnesemia C Hypocalcemia D Hypophosphatemia Preferred response: C e151 Rationale The clinical hallmark of acute pancreatitis is severe, boring epigastric or left upper quadrant pain that radiates through to the back Serum amylase and lipase levels are greatly elevated, and radiographic imaging studies reveal pancreatic enlargement, sonolucency, or irregularity of the margin Ultrasonography is a satisfactory screening technique, but computed tomography scanning should be used when the course is severe If computed tomography scanning is performed with a dynamic, contrast-enhanced technique, interstitial pancreatitis can be differentiated from the more ominous necrotic pancreatitis, which often requires surgical debridement Because serum lipase is almost exclusively pancreatic in origin and amylase comes from a number of organs, the serum lipase concentration may be a better indicator of pancreatitis Use of both measures to follow the course of pancreatitis is preferable to using either one alone Several nonspecific laboratory derangements such as anemia, hypoglycemia, hypocalcemia, and hypoproteinemia may occur Intensive support may be required for severe, acute attacks Severe hemorrhagic necrosis of the pancreas carries a poor prognosis Extraordinarily large third-space fluid and electrolyte losses must be replaced If significant hyperglycemia occurs, insulin must be given Calcium infusions also may be necessary 12 Which of the following agents contributes to a decrease in ammonia production in patients with encephalopathy due to acute liver failure? A Cathartic agents B Hydroxyurea C Lactulose D Neomycin Preferred response: D Rationale Encephalopathy is generally treated by the administration of ammonia-lowering agents Neomycin, by qualitatively altering gut flora, reduces the enteral contribution to the ammonia load Byproducts of the fermentation of lactulose by colonic bacteria reduce luminal pH to trap ammonia as ammonium for excretion in stool Cathartic agents can speed transit of protein through the gastrointestinal tract Dietary protein can be limited and the quality altered to include less aromatic amino acid and more branchedchain amino acid Progressive hepatic encephalopathy culminates in coma When patients have entered a coma, central nervous system (CNS) resuscitation becomes necessary Patients should undergo elective endotracheal intubation, and they should be hyperventilated Administration of narcotics and benzodiazepines should be avoided Benzodiazepine antagonists provide temporary improvement in consciousness among patients with hepatic encephalopathy Beyond CNS metabolic derangements, cytotoxic cerebral edema often complicates hepatic failure Placement of an intracranial monitoring device should be contemplated; the risk of instrumentation in patients with coagulopathy should be weighed against the benefit of continuous CNS pressure monitoring Plasmapheresis or plasma exchange will remove circulating mediators and toxins from patients with liver failure This temporary effect may be due to removal of neuroinhibitory factors e152 S E C T I O N XV Pediatric Critical Care: Board Review Questions Chapter 96: Acute Liver Failure 14-year-old child presents to the Emergency Department of a community hospital with complaints of general malaise, nausea, and jaundice Her medical history is significant for a motor vehicle accident months ago when she sustained fractures of her right tibia and femur On physical examination, she is ill-appearing, jaundiced, has a mild distended abdomen with concern for ascites and mild hepatomegaly Asterixis is present Her laboratory data revealed alanine aminotransferase (ALT), 4503 U/L; aspartate aminotransferase (AST), 5604 U/L; total bilirubin, 14.5 µmol/L; direct bilirubin, 12 µmol/L, international normalized unit (INR), 3.4; serum sodium, 126 mEq/L; serum creatinine, 1.2 mg/dL The complete blood cell count was within normal limits The next best step in the management of this patient is: A Admit to the general pediatric ward of the hospital B Consult the pediatric gastroenterologist C Follow-up with her pediatrician the next day D Transfer the patient to a facility with potential for liver transplant evaluation Preferred response: D Rationale This patient is presenting to the emergency department with most likely a new diagnosis of acute liver failure with laboratory findings suggesting acute kidney injury and coagulopathy Her clinical examination is concerning for hepatic encephalopathy Given the constellation of signs and symptoms, the best action is to transfer the patient to a facility with potential for liver transplant evaluation Despite supportive care, the child in question continues to have worsening neurologic status, with altered mental status and combativeness The most appropriate next step would be to: A Initiate neuroprotective hypothermia B Obtain computerized tomography of the head C Obtain neurosurgical consult for intracranial pressure (ICP) monitoring D Perform endotracheal intubation for airway protection and initiate neuroprotective measure Preferred response: D Rationale This patient has a diagnosis of acute liver failure and her clinical examination suggests progressing hepatic encephalopathy The most appropriate action is to perform endotracheal intubation for airway protection, followed by continuing neuroprotective measures Although a head CT may be useful, ICP monitoring is controversial Regarding the same patient in questions and 2: You have performed endotracheal intubation and instituted neuroprotective measures for this patient, but the urine output has been progressively decreasing over 24 hours The patient is now anuric The most appropriate next step is: A Continue present management since her kidney function will recover after liver transplant B Initiate continuous renal replacement therapy C Perform a kidney biopsy D Remove the patient from the transplant list due to her high acuity state Preferred response: B Rationale This patient has acute liver failure, coagulopathy, hepatic encephalopathy and now progressing acute kidney injury with presumed hepatorenal syndrome, for which continuous renal replacement therapy should be initiated A 5-year-old male presents with possible acute liver failure after a 1-week history of rhinorrhea, cough, and congestion, for which he has been taking acetaminophen Upon presentation the following laboratory tests were obtained: INR, 4.0; total bilirubin, 19 µmol/L; aspartate aminotransferase (AST), 1243 U/L; alanine aminotransferase (ALT), 2810 U/L; WBC, 109/L; hemoglobin, 11.3 g/dL; hematocrit, 33%; platelets, 302 109/L; ammonia, 30 µmol/L; and gamma glutamyl transferase (GGT), 316 U/L Evaluation in the emergency room demonstrates a child who appears tired, has no respiratory distress, and answers questions appropriately but slower than usual per parental report Which of the following choices is correct regarding this patient? A Admission or transfer to a liver transplantation center early on in the clinical course may decrease morbidity and mortality B Because the ammonia is normal, the patient’s mental status is due to his viral illness and not developing hepatic encephalopathy C The cause of acute liver failure is definitely acetaminophen ingestion D The patient’s prognosis is poor given the high laboratory values upon presentation Preferred response: A Rationale Choice A is correct, because anticipation and early identification of patients who go on to need liver transplantation can help lessen poor outcomes Choice B is incorrect because stage hepatic encephalopathy can be subtle and may be confused with fatigue from other causes Although trending ammonia may help with determining the progression of liver failure, there is not always a correlation between stages of encephalopathy and laboratory values Parental observation and history may be better indicators of developing hepatic encephalopathy Choice C is incorrect because the causes of liver failure can include a multitude of etiologies and can be multifactorial Given that the patient also presented with a viral prodrome, viral etiologies should also be considered A thorough workup for various etiologies of liver failure should be initiated Choice D is incorrect because prognostication is difficult to assess without knowing the trajectory of clinical course Currently in pediatric acute liver failure, there remains a paucity of prognostic tools to determine outcome CHAPTER 136 Board Review Questions e153 The previously mentioned 5-year-old male was then transferred to a pediatric liver transplantation center and received a left lateral segment liver transplant week later due to worsening laboratory values and progression of hepatic encephalopathy Which of the following is correct about the postoperative period? A It should be anticipated that the patient will need substantial analgesia and sedation for many days because of the extensive surgical procedure he has undergone B Infection can be a major cause of morbidity post–liver transplant, and the patient should be carefully assessed C There is no hurry to wean this patient from the ventilator after liver transplantation D Transaminitis without coagulopathy detected on postoperative day is probably due to primary nonfunction of the allograft Preferred response: B Which of the following is the most sensitive indicator of coagulopathy in the setting of acute liver failure? A Decrease in factor VII B Decrease in factor VIII C Decrease in fibrinogen D Prolongation of prothrombin time Preferred response: A Rationale A 6-year-old child is admitted to the PICU with acute liver failure due to acetaminophen ingestion Laboratory results demonstrate platelet count, 53,000/µL; prothrombin time, 43 seconds; partial thromboplastin time, 65 seconds; hemoglobin, 8.5 g/dL; and fibrinogen, 120 mg/dL The patient has oozing from the site of a line insertion A computerized tomographic scan of the head rules out intracranial hemorrhage Besides administering N-acetylcysteine, your next step in the management of this patient would be to transfuse which of the following? A Cryoprecipitate B Factor VIIa C Fresh frozen plasma D Platelets Preferred response: C Sepsis is a major cause of morbidity given the degree of immunosuppression and abdominal surgery Choice A is incorrect The patient should be carefully assessed for discomfort and appropriately treated, but pain can be expected to resolve rapidly in the first few days Excessive and prolonged use of sedative medication and opiate analgesia delays recovery and leads to the need for prolonged ventilator support and poor gastrointestinal motility Choice C is incorrect because prolonged ventilator support is associated with increased complications, prolonged ICU stays, and delayed discharge from the hospital Choice D is incorrect because primary liver dysfunction can present with transaminitis and should always be considered but if present is associated with coagulopathy immediately after the operation and does not appear this late after implantation Acute allograft rejection, major hepatic vessel thrombosis, infection, and biliary complications are among the differential diagnoses Which of the following coagulation factors is either normal or elevated in acute liver failure (ALF)? A Factor II B Factor V C Factor VII D Factor VIII Preferred response: D Rationale The coagulation factors synthesized by hepatocytes include factors I (fibrinogen), II (prothrombin), V, VII, IX, and X, and a reduction in synthesis leads to the prolongation of prothrombin and partial thromboplastin time The prothrombin time is the most clinically useful measure of hepatic synthesis of clotting factors Prolongation of the prothrombin time often precedes other clinical evidence of hepatic failure, such as encephalopathy, and may alert the clinician to the severity of acute hepatitis; it is a guide to the urgency of liver transplantation Fibrinogen (factor I) concentrations are usually normal unless there is increased consumption such as in disseminated intravascular coagulation (DIC) The level of factor VIII may help differentiate between DIC and ALF, as factor VIII is synthesized by vascular endothelium and therefore is normal or increased in ALF, as an acute-phase response or due to decreased utilization Rationale The prothrombin time depends on the availability of factor VII, which has the shortest half-life (4–7 hours) of the clotting factors and decreases more rapidly than other liver-derived clotting factors when production does not keep up with its utilization As a result, measurement of factor VII is a more sensitive indicator than the prothrombin time but is typically not as readily available Factor VIII is synthesized by vascular endothelium and therefore is normal or increased in acute liver failure Rationale Although in the early stages of assessment, prolongation of prothrombin time is a sensitive guide to prognosis and the need for liver transplantation, life-threatening coagulopathy should be corrected with fresh frozen plasma (FFP), platelets, and cryoprecipitate as needed It is not necessary to maintain coagulation parameters (prothrombin time) in the normal range In general, mild to moderate coagulopathy (prothrombin time ,25 seconds) requires no therapy except support for procedures Marked coagulopathy (prothrombin time 40 seconds) should be corrected (10 mL/kg of FFP every hours) to prevent the risk of bleeding, particularly intracranial hemorrhage This child is not actively bleeding but has a prothrombin time of longer than 40 seconds, so she should receive FFP Administration of recombinant factor VIIa corrects the coagulation defect in patients with acute liver failure for a period of to 12 hours only It is not warranted in this situation Cryoprecipitate is used in patients with acute liver failure who have marked hypofibrinogenemia or are actively bleeding, or prior to invasive procedures e154 S E C T I O N XV Pediatric Critical Care: Board Review Questions Chapter 97: Hepatic Transplantation Which of the following statements regarding liver transplantation is most accurate? A A total of three anastomoses is required for the liver transplantation procedure B Living donor transplantation has not affected graft survival C The Roux-en-Y limb of the Kasai portoenterostomy is typically used for graft bile duct anastomosis in patients with biliary atresia D The use of technical variant grafts has increased the number of organs available for transplantation but has not changed times on the waiting list Preferred response: C Rationale The liver transplantation operation is complex and requires four anastomoses including three vascular anastomoses (hepatic artery, hepatic vein, and portal vein) as well as the biliary tree In children with biliary atresia a Roux-en-Y limb is created during the Kasai portoenterostomy and then is used for graft bile duct anastomosis in those who require liver transplantation Technical variant grafts have increase the number of organs available for transplantation and has decreased the time children spend on the waiting list Their use however has been associated with an increased incidence of vascular and biliary complications when compared to whole organ transplants but no change in survival Living donor grafts have been associated with improved shortand long-term graft and patient survival compared to deceased donor transplantation Which of the following best describes complications of liver transplantation? A Acute cellular rejection is the most common complication and is most common in the first months posttransplantation B Any postoperative coagulopathy associated with hemorrhage should be corrected aggressively with plasma and platelets C Biliary structures are highly sensitive to ischemic injury and are particularly dependent on portal blood flow D Grafts have no further complications when emergent reexploration for hepatic artery thrombosis restores arterial flow grafts have no further complications Preferred response: A Rationale Hepatic artery thrombosis (HAT) is a potentially devastating complication of liver transplantation HAT is an indication for emergent re-exploration with thrombectomy or thrombolysis and revision However, even with restoration of good arterial flow, biliary stricture or hepatic necrosis may result and retransplantation may be necessary Therapeutic anticoagulation should be initiated Postoperative bleeding should be managed carefully Blood products transfusion should be considered when patients experience hemorrhage but hyperviscosity and aggressive correction of coagulopathy and thrombocytopenia should be avoided to limit the potential contribution to vascular thrombosis Biliary complications including strictures are the most frequent surgical complication of liver transplantation and may occur early or late after transplantation The graft bile duct is sensitive to ischemic injury but is particularly dependent on hepatic arterial flow for perfusion, not portal vein flow Which if the following statements is most accurate regarding children who have undergone liver transplantation? A Acute rejection usually manifests as altered hemorrhage or altered mental status B Complications of calcineurin inhibitors include neurologic and renal injury but not unstable levels C Infection with cytomegalovirus (CMV) and Epstein-Barr virus (EBV) occur and risk is related to recipient status at the time of transplantation D Transaminases usually being to rise 24–36 hours after transplant and peak at 3–4 days Preferred response: C Rationale Hepatocellular enzymes alanine aminotransferase (ALT) and aspartate aminotransferase (AST) usually begin within the first 24 hours posttransplant, reflecting hepatocellular injury related to ischemia and reperfusion of the liver Normally, with good perfusion, transaminase levels often start to decline 24–36 hours posttransplant The calcineurin inhibitor (CNI), tacrolimus, serves as the mainstay of maintenance immunosuppression regimens Complications of CNIs include nephrotoxicity, neurotoxicity, gastrointestinal disturbances, and hyperglycemia CNIs levels can be unstable as they are metabolized by cytochrome P-450, and clearance and serum levels can be dramatically impacted by other medications that interact with the P-450 system, such as certain antifungal agents, antibiotics, and anticonvulsants Acute cellular rejection is the most common complication following transplantation Children with acute rejection often remain asymptomatic, and diagnosis is suspected based on abnormal liver function studies The diagnosis of rejection is confirmed on liver biopsy Episodes of acute rejection often respond completely to treatment with short courses of high-dose corticosteroid therapy and rarely lead to graft loss CMV and EBV infection may develop after transplantation The risk is most related to recipient CMV and EBV status at the time of transplant, but is also influenced by level of immunosuppression Donor-origin infection is rare, and may not present until several months after transplant, requiring a high index of suspicion for accurate diagnosis Chapter 98: Acute Abdomen Which of the following injuries mandates a laparotomy? A Grade II splenic hematoma B Grade II hepatic hematoma C Grade I renal injury D Intraperitoneal bladder rupture Preferred response: D Rationale Intraperitoneal bladder rupture requires laparotomy because the urine will continue to extravasate into the peritoneal cavity causing sepsis and increased BUN/creatinine A laparotomy will allow the surgeon to close the laceration Extraperitoneal bladder injuries have been shown to heal with simple catheter drainage of the bladder CHAPTER 136 Board Review Questions Outside of laparotomy, what is the best diagnostic modality to identify the specific nature and extent of blunt intraabdominal injury? A Computed tomography (CT) B Diagnostic laparoscopy C Diagnostic peritoneal lavage D Focused abdominal sonography for trauma Preferred response: A Rationale A CT scan is the only imaging modality listed to provide organspecific information as to the location and extent of injuries in the abdomen A 3-year-old girl weighing 20 kg has been admitted to the intensive care unit for management of sepsis following a 6-day course of fever and abdominal pain and an exploratory laparotomy 18 hours ago for a perforated appendicitis She is receiving intravenous piperacillin and tazobactam and 80 mL/h of D5 in 0.45 saline solution She has a fever of 38.8°C, is undergoing mechanical ventilation, has a heart rate of 120 beats per minute, and has a mean arterial pressure of 45 mm Hg Her urine output is 50 mL during the past hours Which of the following is the most appropriate next step in her management? A Administer an intravenous saline solution bolus of 400 mL B Administer an intravenous bolus of 10 mg of furosemide C Change her antibiotics to broaden her antibiotic coverage D Check her gastric pressure using the nasogastric tube Preferred response: A e155 Rationale This child had intestinal ischemia severe enough to warrant resection of a large segment of his small intestine Therefore the entire midgut had compromised perfusion, including the bowel that was not resected His acidosis and hyperlactatemia are most likely due to persistent ischemia of the remaining bowel, and no diagnostic imaging test can accurately determine the viability of that bowel Therefore a laparotomy is a reasonable diagnostic and therapeutic intervention A colonoscopy would not answer the intestinal viability question, and the gaseous distension that might result from insufflation during the procedure could make the intestinal ischemia worse Sodium bicarbonate will be of limited benefit in conditions of ongoing acid production by the ischemic bowel Chapter 99: Nutrition of the Critically Ill Child Compared to healthy children, which of the following best describes the metabolic state of critically ill children: A A risk of underfeeding as well as overfeeding is prevalent B Energy expenditure is always higher and therefore resulting in an increased energy requirement C Nutritional support can prevent or reverse the metabolic stress response to critical illness or injury D Protein breakdown stimulates a higher protein synthesis, resulting in a net positive protein balance E Standard equations allow accurate estimation of energy requirements Preferred response: A Rationale Rationale This patient underwent surgery only 18 hours ago for a severe intraabdominal infection and has fever, tachycardia, oliguria, and hypotension Her intravenous fluid maintenance rate is only 96 mL per kg per day The most likely explanation for oliguria within 24 hours of surgery is hypovolemia, and thus she should respond to an empiric bolus of fluid Diuretic use should not be considered in the first 24 hours after surgery unless hypovolemia has been excluded Although abdominal compartment syndrome could become a concern, it is unlikely at this early postoperative juncture It is much easier to measure bladder pressure than intragastric pressure The current antibiotic choice should be adequate for intraabdominal sepsis from appendicitis Critical illness, secondary to trauma, burns, infection or surgery, is followed by a metabolic stress response that is characterized by protein breakdown as an adaptive strategy Importantly, nutritional support itself cannot reverse or prevent the metabolic stress response but may help offset the catabolic losses, particularly protein losses, during this state Failure to provide optimal calories and protein during the acute stage of illness may exaggerate existing nutritional deficiencies and further exacerbate underlying nutritional status Although protein synthesis is increased, it may not be able to offset the losses from protein breakdown and results in a net negative protein balance Energy demands from metabolic stress response may be variable and are often unpredictable Standard equations used to estimate energy requirements were developed in healthy children, and therefore might underestimate or overestimate energy requirements This results in unintended overfeeding or underfeeding in this group Indirect calorimetry is the gold standard for energy expenditure assessment in critically ill patients 4 A 12-year-old, 55-kg boy presented 48 hours ago with midgut volvulus resulting in intestinal ischemia, which required resection of approximately half of his small intestine His vital signs are as follows: heart rate, 100 beats per minute; blood pressure, 105/60 mm Hg; and pulse oximetry, 94% on L of oxygen via nasal cannula with a fraction of inspired oxygen of 0.50 Arterial blood gas findings reveal the following values: pH, 7.24; Paco2, 36 mm Hg; Pao2, 58 mm Hg; and HCO3, 17 mmol/L His urine output is 30 mL per hour His amylase is 250 units/L (normal, ,120 units/L), and his lactate level has been at 2.8 mmol/L (normal, ,1 mmol/L) for 12 hours Which of the following would be the most appropriate next step? A Administer sodium bicarbonate B Obtain an abdominal and pelvic CT scan with enteral contrast C Perform a colonoscopy D Administer a surgical reexploration Preferred response: D Select all true options regarding enteral nutrition (EN) in critically ill children A EN should be initiated after the first week of critical illness B Early EN is associated with increased infectious episodes in critically ill children C Early EN use is safe and is associated with improved outcomes D The postpyloric route is preferred for EN in critically ill children E Use of vasoactive infusions is a contraindication for EN Preferred response: C ... mEq/L; serum creatinine, 1.2 mg/dL The complete blood cell count was within normal limits The next best step in the management of this patient is: A Admit to the general pediatric ward of the hospital... therefore might underestimate or overestimate energy requirements This results in unintended overfeeding or underfeeding in this group Indirect calorimetry is the gold standard for energy expenditure... intubation for airway protection and initiate neuroprotective measure Preferred response: D Rationale This patient has a diagnosis of acute liver failure and her clinical examination suggests progressing