Perirectal Abscess Gastrointestinal Infection

Initial medical management of perirectal abscess includes sitz baths to provide symptom- atic relief as well as laxatives and stool softeners to minimize painful defecation and prevent fi s- sures and tears. As with enterocolitis, broad- spectrum parenteral antibiotics should be utilized. GCSF can be considered in the neutropenic patient although there is no evidence to support its usage. Surgical management may include incision and drainage, debridement, or further intervention but only if there is a fl uctuant mass, large amounts of necrotic tissue, progression to necrotizing fasciitis, or a persistent fi stula Arul and Spicer 2008 ; Pizzo 2011 .

7.3 Gastrointestinal

Hemorrhage Severe GI hemorrhage requires immediate medical, and potentially, surgical intervention. Common etiologies include gastritis or esophagi- tis, ulcers, necrotizing pancreatitis, primary GI tumors, infection, and radiation-induced infl am- mation and micro vascular damage i.e., mucosal telangiectasias. Hemorrhagic gastritis of varying severity may occur in almost half of pediatric oncology patients Kaste et al. 1999 . Common etiologies of ulcer formation include peptic ulcer disease, infection, increased intracranial pressure stimulating the vagal nerve and parietal cells Cushing’s ulcer, and steroids. Esophageal bleeding results from progressive esophageal varices associated with portal hypertension or Mallory-Weiss tears with repeated emesis. Tumors precipitate bleeding by vascular infi ltra- tion or abnormal tumor vessel growth direct damage as well as infarctions and lacerations via mass effect indirect damage. Common infec- tious agents that may trigger signifi cant bleeding include fungi such as Candida spp., viral patho- gens including Herpesviridae , C. diffi cile , and the opportunistic protozoan cryptosporidium Kaste et al. 1999 ; Fisher and Rheingold 2011 . Sepsis and disseminated intravascular coagula- tion can exacerbate bleeding. Anti- angiogenic chemotherapeutic agents such as bevacizumab, sunitinib, and sorafenib can cause severe bleeding, poor wound healing, and gastric perfo- ration; such adverse manifestations should prompt immediate discontinuation. Ginkgo biloba, a commonly utilized nutritional supplement for fatigue, depression and memory loss, has been associated with an increased bleeding risk Demshar et al. 2011 . Oncology patients should avoid aspirin and nonsteroidal anti- infl ammatory drugs NSAIDs to reduce bleeding risk. Signs and symptoms of GI hemorrhage vary. Symptoms include pain, hematemesis, melena or hematochezia, and anemia-induced symptoms and signs such as fatigue, headache, dizziness, syncope, dyspnea, pallor, and oliguria. To pre- vent aspiration, the patient’s head of the bed should be at an angle of 30–45° Fisher and Rheingold 2011 . In the patient with signs or symptoms of volume depletion, immediate bolus intravenous isotonic crystalloid fl uids should be initiated and type O − red blood cells considered while awaiting results of blood counts and for preparation of crossmatched packed red blood cells. If thrombocytopenia is suspected, empiric platelet transfusion can also be considered. If hypotension persists despite appropriate fl uids and blood products, vasopressors are indicated. The initial emergent laboratory workup includes: 1 complete blood count CBC to evaluate severity of anemia and thrombocytopenia; 2 coagulation evaluation with prothrombin, partial thromboplastin time and fi brinogen; and 3 type and cross in preparation for blood products. Setting goals and anticipating blood loss will maximize safety. Goals include: 1 correction of anemia, with maintenance of hemoglobin ≥8 g dL; 2 correction of throm bocytopenia, with maintenance of platelets ≥75 × 10 9 L; and 3 correction of any coagulopathy with either fresh frozen plasma or fi brinogen. Complete gut rest may be augmented with histamine blockers or proton pump inhibitors. The necessity of gastric lavage remains unclear. In non-oncology adult patients, the aspirate results determine an individual’s pre- endoscopic risk stratifi cation. A high-risk lesion consists of a bleeding lesion or visible vessel on endoscopy. A bloody versus “coffee-ground” or bilious aspirate is 75 specifi c for an active upper GI bleed Abdulrahman et al. 2004 . Less is known about the utility of gastric lavage in pediatric oncology patients. In children with bright red blood or evidence of brisk bleeding during gastric lavage, management includes prompt endoscopic ligation or sclerotherapy. If the patient has esophageal varices, systemic infu- sion of vasopressin for 24 h may decrease portal circulation enough to halt bleeding without endoscopic intervention. Although endoscopy potentially increases the risk of infection in neutropenic patients, it is the standard method to identify and control both upper and lower GI hemorrhage. If endoscopy fails to identify the origin of the bleed, angiogra- phy or radionuclide scans may help localize the source, assuming that the rate of bleeding exceeds 1 or 0.5 mLmin for these different diagnostic methodologies, respectively. If hemorrhage per- sists or recurs, management includes reevalua- tion and treatment of anemia, thrombocytopenia, and coagulopathies followed by repeat endos- copy or surgical intervention Arul and Spicer 2008 . Surgical intervention should precede endoscopic hemostasis if bleeding is associated with tumor. Figure 7.1 outlines the algorithmic approach to the management of acute GI bleed- ing in pediatric oncology patients.

7.4 Pancreatitis

Pancreatitis represents a rare but well-known complication of multiple chemotherapeutic agents, most notably asparaginase, steroids, mer- captopurine and cytarabine Haut 2005 ; Trivedi and Pichumoni 2005 ; Garg et al. 2010 . L-asparaginase and PEG-asparaginase derived from E. coli are well described for inducing acute pancreatitis of all degrees of severity with a reported incidence of 2–18 Knoderer et al. 2007 ; Kearney et al. 2009 . Although suggested in some studies, it is not clear that PEG- asparaginase leads to an increased risk of pancre- atitis as compared to L-asparaginase Silverman et al. 2001 ; Knoderer et al. 2007 . Older patients i.e. 9 years have been noted to have a signifi cantly increased risk of pancreatitis with pancreatitis occurring early after asparagi- nase introduction and typically days after L-asparaginase and weeks after PEG- asparaginase secondary to differences in drug half-life Silverman et al. 2001 ; Knoderer et al. 2007 ; Kearney et al. 2009 . No difference in pan- creatits incidence has been noted with intramus- cular versus intravenous PEG-asparaginase to date Silverman et al. 2010 . In their retrospec - tive review, Knoderer et al. 2007 note that asparaginase-associated pancreatitis was signifi - cantly correlated with concomitant prednisone and daunomycin and signifi cantly less likely with dexamethasone. Reintroduction of aspara- ginase after pancreatitis is controversial. In their review, Kearney et al. 2009 did not show a sig- nifi cant difference in outcome in those patients with and without pancreatitis although their gen- eral practice was to rechallenge patients. Knoderer et al. 2007 reported a 7.7 incidence of pancreatitis with rechallenge as compared to Kearney et al. 2009 who reported a 63 recurrence rate. Clinical diagnosis of asparagi- nase-associated pancreatitis is relatively straight- forward; Kearney et al. 2009 note that all patients presented with abdominal or back pain and the majority had nausea or emesis. Severity of pancreatitis was not noted to correlate with degree of elevation of amylase and lipase Kearney et al. 2009 . Laboratory workup merely supports the clini- cal suspicion of acute pancreatitis. Initial labora- tory tests should include: 1 electrolytes to evaluate for hypocalcemia secondary to its pre- cipitation; 2 renal and liver function tests to monitor for multiorgan failure secondary to cyto- kine release from the infl amed or necrotic pan- creas; 3 triglycerides, inciting agents that when hydrolyzed to free fatty acids lead to free radical damage; and 4 the exocrine enzymes amylase and lipase, which when elevated suggest pancre- atic autodigestion and are the hallmark of diagno- sis Tsuang et al. 2009 . Of note, amylase and lipase may not be signifi cantly elevated. Excessive cytokine release can lead to respiratory distress and therefore arterial blood gas and chest radiog- raphy may be clinically indicated for proper man- agement Arul and Spicer 2008 .