For the critically ill patient with an intra-abdominal infection, perforation, or ischemic process, timely resuscitation is crucial to their survival. Resuscitative efforts should begin when the patient enters the hospital, rather than waiting for admission to the ICU. During a thorough diagnostic workup with a history and physical, laboratory values and imaging, findings such as severe peritonitis, portal venous gas, or free intraperitoneal air may be discovered that necessitate immediate intervention. In these cases, the need for intervention supersedes the need for ICU admission. Without source control, peritoneal soiling will continue, and the patient’s condition will continue to deteriorate. The patient should be prepared for the operating room. Due to the global vasodilatory effects of anesthesia, the patient should receive rapid volume loading. Resuscitative efforts can continue intraoperatively, led by a combined effort of the surgeon and anesthesiologist.

In patients not requiring immediate operative intervention, resuscitation should begin rapidly. Supplemental oxygen should be provided, with a secure airway by endotracheal intubation, if indicated. Lung-protective ventilatory strategy should also be employed to prevent volutrauma, with tidal volumes of approximately 6 ml per kg of ideal body weight [15]. Adequate venous and arterial access should be gained to infuse fluids and blood products as well as provide invasive hemodynamic monitoring and easy blood sampling. Pulmonary artery catheters should be carefully considered, but have proven to be of marginal assistance when the patient is unresponsive to fluid resuscitation [16].

Appropriate resuscitative goals must be established and pursued for each patient, starting by using crystalloid solution to achieve a central venous pressure of 8 to 12 mm Hg. Vasopressors, namely, norepinephrine, should be used to achieve a mean arterial pressure of 65 mm Hg, with supplemental low dose vasopressin use, if necessary. Transfusion of packed red cells should be considered in patients with active bleeding or with hemoglobin less than 7 g per dL, to augment oxygen delivery. In addition to the standard hemodynamic parameters, oxygen delivery parameters such as continuous mixed venous oxygen saturation (SvO2) or mixed central venous oxygen saturation (ScvO2) may be followed. ScvO2 of more than 70% is desirable, with transfusion or pressor therapy to achieve this endpoint. Arterial lactate clearance is another useful parameter. A lactate clearance of at least 10%, measured at 2-hour intervals, has been recently demonstrated to be equal to ScvO2 as an indicator of response to resuscitation. More traditional endpoints should also be considered, such as adequate urine
output and serial physical exam, specifically extremity warmth and level of consciousness. Newer measures such as tissue oxygen saturation measured by near infrared spectroscopy are being studied and may be beneficial as additional noninvasive means of guiding resuscitative efforts [16,17,18,19,20,21,22].

Blood cultures should be obtained upon admission, ideally before administration of intravenous antibiotics. Antibiotic therapy should be started immediately. Broad-spectrum antibiotics against Gram-positive, Gram-negative, and anaerobic bacterial organisms should be chosen. Antifungal coverage should be considered, especially if there is an upper gastrointestinal source, in those on long-term antibiotics or in an immunosuppressed patient [17,23].

Sepsis may be complicated by coagulopathy and DIC. For the patient about to undergo an operation, coagulopathy should be reversed with FFP and/or cryoprecipitate, and platelets should be transfused if counts are less than 50,000 per mm³. Thromboelastography (TEG) is being increasingly used in ICUs and may prove beneficial for patients with intra-abdominal sepsis [24,25,26] (see Fig. 150.1).

First of the surgical concerns during management of any intra-abdominal infection is achieving source control. The infectious or inflammatory process should be removed. All compartments of the abdomen should be explored, including the subphrenic, subhepatic, pelvic, and interloop spaces. All abscesses are drained, all inflamed or perforated bowel is resected, and the abdomen is irrigated with copious amounts of warm saline. The mantra “drainage, debridement, diversion then drugs” expresses the surgeon’s opinion about the importance of gaining source control.

After source control is achieved, the surgeon turns their attention to intra-abdominal reconstruction. Primary anastomosis is nearly always performed after resection of small bowel segments. Large intestinal reconstruction is not as straight forward. The majority of data regarding restoring intestinal continuity in the setting of diffuse peritonitis is taken from the treatment of diverticulitis. A two-stage procedure is the default operative mode in sick patients. After resection of all inflamed bowel, this involves creation of an end colostomy proximally and leaving a rectal stump distally, with the intention of restoration of intestinal continuity at a future date. The goal of a two-stage procedure is to avoid anastomotic dehiscence. This procedure is associated with its own morbidities, including stoma complications, abscess formation, and leakage. Primary anastomosis, with on-table colonic washout is increasingly used in perforated diverticulitis, with the goal of avoiding morbidity of stoma complications and need for future laparotomy. Mortality and complications have been shown to be similar to two-stage procedure, with similar operative times. These studies involve heavy selection bias, thus primary anastomosis is still not universally accepted as an alternative to two-stage procedure. The most important factors for the surgeon to consider are the amount of peritoneal soilage and the hemodynamic status of the patient. Patients with perioperative shock, especially those on vasopressors, should not undergo primary anastomosis of small or large bowel [27,28,29,30].

In the patient with diffuse peritonitis, after a stoma or anastomosis is created, a drain is usually placed. Closed suction drains (Jackson-Pratt or Blake type) are preferred to open drains (Penrose type). Drain tips are positioned near the inflamed organ, in paracolic gutters or another dependent
portion of the abdomen and exit through the skin and fascia, away from the laparotomy incision. These drains allowed continued efflux of contaminated material from the abdomen. Change in character or quantity of the effluent should raise suspicions of leak or need for further debridement. Absence of drainage, though, may be a sign of a nonfunctioning drain rather than a sign of lack of continued pathology. Drain removal is a variable and stepwise process. Patients often keep drains until enteral diet is tolerated. Occasionally, patients are discharged with drains in place.

A critically ill patient who is likely not to eat in the near future should have a feeding tube placed. Various feeding tubes are used, including nasogastric, gastric, jejunostomy, or g-j tubes, allowing for gastric decompression and jejunal feeding simultaneously.

Though the open abdomen has long been a part of postoperative management of patients, the term “damage control surgery” has only recently been coined. Damage control was first used in the management of traumatic injuries, but is applicable in the setting of inflammatory, infectious, and vascular pathology in the abdomen of a patient in extremis. This process is now the subject of extensive study as a deliberate process in management. The intensivist’s role in this strategy is paramount [31].

Damage control surgery (DCS) is defined as an abbreviated laparotomy, consisting of gaining control of bleeding and contamination in a patient on the verge of physiologic collapse. DCS is designed to help solve the problem of the lethal triad of acidosis, coagulopathy, and hypothermia. This triad continues to develop intraoperatively and can lead to patient death despite a technically correct operation [31,32].

Selecting the proper patient for this strategy is based on criteria involving disease process and physiologic status. The decision is made early in the preoperative or intraoperative phase of care by the surgeon, with constant communication with the anesthesiologist. These criteria have been defined by multiple authors. The disease based criteria consist of an inaccessible injury, multiple severe injuries, severe contamination, need for a time consuming procedure, need for a second look to reevaluate the intra-abdominal contents or inability to close abdominal fascia. The physiologic criteria include hypothermia (< 35°C), metabolic acidosis (< 7.30), nonmechanical bleeding, and poor response to resuscitation [33].

Three general phases of damage control are described. In the initial phase, the abbreviated laparotomy involves a thorough exploration and control of bleeding, and then contamination. No reconstruction efforts are made at this time. The abdomen is closed with towel clamps, a running nylon skin suture, or a layered vacuum assisted closure.

Second is the resuscitative phase. This involves establishing clean IV access and removing femoral lines if possible. A ventilation strategy should have the goal of oxygenation and ventilation while avoiding volutrauma from excess tidal volumes and careful use of Positive End-Expiratory Pressure (PEEP) to avoid diminishing venous return. Fluid and product resuscitation should be used to correct acidosis, restore normal tissue perfusion, and optimize oxygen delivery. This should all be done in a warm ICU room with warm IV fluids to correct hypothermia. Twelve to 48 hours should be allowed for the completion of resuscitation [31,32,33,34].

Third is the definitive operation, when packs are removed, the abdomen is reexplored, reconstruction is undertaken, and the abdomen is irrigated [31,32,33,34]. Abdominal closure is also part of the definitive operation. Frequently a tension free closure of fascia is not possible. In this case, surgeons often elect for replacing the suction assisted closure in conjunction with a progressive closure strategy. Several strategies exist but all involve changing abdominal dressings every 2 to 3 days and progressively cinching the dressing with re-approximation of the fascia. The goals of these strategies are to provide negative pressure to the wound and continuous evenly distributed fascial traction. Some choose a planned ventral hernia, in which only the skin is closed. This requires reoperation in several months, but avoids placement of a foreign body. Other surgeons perform a fascial closure with absorbable mesh, allow granulation to occur, and then place a skin graft [35,36,37,38,39,40,41,42].

Occasionally, while the patient is undergoing resuscitation, an unplanned operation is necessary. Problems arise such as bleeding, abdominal compartment syndrome, or continued septic shock. Abdominal compartment syndrome is a life threatening condition that develops during resuscitation due to accumulation of fluids and intra-abdominal swelling or due to continued bleeding. Compartment syndrome may present as decreased pulmonary compliance on the ventilator resulting in peak inspiratory pressures more than 40 cm H₂O, as cardiovascular collapse due to decreased venous return or as elevated bladder pressures more than 20 mm Hg with decreasing urine output [31,32,33,34].

The intensivist should also be aware of common postoperative problems, namely abscess and fistula formation. If fevers, ileus, or wound drainage arise during this phase, CT scan of the abdomen and pelvis are performed at approximately postoperative day 7. If any suspicious fluid collections are found, they can then be drained percutaneously.

A critically ill patient with a suspected intra-abdominal process and a clinical exam consistent with peritonitis should be taken to the operating room for exploration and treatment. Without such findings on exam, diagnostic imaging is the next important step in the management of these patients.

Routinely, plain abdominal X-rays are obtained. They are easily acquired, have minimal radiation exposure, and can be done at the bedside. The acute abdominal series routinely consists of upright chest, upright abdominal, and supine abdominal films. Plain films have shown the most utility in the diagnosis of the perforated viscous and acute intestinal obstruction. For proper detection of free air, 5 to 10 minutes in the upright position are necessary before performing the study, to allow air to move to a visible location under the diaphragms. If the patient is unable to maintain an upright position, left lateral decubitus position is the next best. Plain films may demonstrate an obstructive process, showing distended bowel loops, step ladder air–fluid levels, and a paucity of distal bowel gas. Frequently however, critically ill patients are unable to sit upright or in a decubitus position for any amount of time. In addition, plain films lack the diagnostic accuracy to discover most intra-abdominal infections, and another mode is needed [43,44,45].

Computed tomography (CT) is the gold standard for the diagnosis of intra-abdominal processes, their locations and complications, with superior sensitivity and specificity for a range of life threatening diseases including, but not limited to, mesenteric ischemia, hernia, pancreatitis, diverticular abscess, and aneurysmal disease. Helical CT technology has improved both the quality and ease of administration of CT scans. Despite its diagnostic superiority, CT is not without its problems, especially in the ICU setting. Many critically ill patients are unable to be transferred to the radiology suite. Some morbidly obese patients are unable to fit into conventional scanners. CT scans obtained for suspected intra-abdominal infection should be performed with intravenous, oral, and sometimes rectal contrast. Failure to use contrast can significantly decrease
diagnostic accuracy. Many ICU patients are unable to receive contrast, due to renal insufficiency or inability to tolerate orally administered contrast. Decisions about the use of contrast should be made with careful consideration weighing the input from surgeons and radiologists alike [43,44,45].

Ultrasound (US) is the workhorse of the ICU. In addition to its use as a tool in obtaining central and arterial access, echocardiography, bladder scans, focused abdominal sonogram for trauma (FAST), thoracentesis, and the detection of DVTs, ultrasound is a portable technology with applications in diagnosis and treatment of many intra-abdominal processes at the bedside in the ICU. US is the diagnostic procedure of choice in the setting of right upper quadrant diseases such as acalculous cholecystitis and hepatic lesions, as well as in pelvic diseases including ovarian torsion, PID, and ectopic pregnancy. US is also used at the bedside by the interventional radiologist to percutaneously drain abdominal fluid collections. In addition, US techniques are expanding to include natural orifice transluminal endoscopic surgery (NOTES) procedures for endoscopic ultrasound (EUS) guided drainage of collections in the chest, abdomen, and pelvis. Limitations of ultrasound include poor imaging with increased body wall thickness and bowel gas interference [44,45,46,47,48,49].

In the era of increasing use of minimally invasive technologies, bedside laparoscopy in the ICU is increasingly common and safe. Bedside laparoscopy can be performed by an abdominal drain tract or new port site. In addition, new devices are being developed that can be used without general anesthesia or pneumoperitoneum. The utility of bedside laparoscopy lies in its ability to diagnose various conditions such as mesenteric ischemia and cholecystitis or for use in trauma, while avoiding the morbidity of an exploratory laparotomy in a critically ill patient [50,51,52,53].

Once intra-abdominal infection is recognized, and resuscitation and antibiotics have been started, a decision must be made regarding the most appropriate avenue for gaining source control. Percutaneous abscess drainage (PAD) has replaced the need for emergent operative intervention in the management of many intra-abdominal processes [20]. In some patients who become asymptomatic after drainage, PAD provides definitive therapy. In those with ultimately fatal diseases, palliation is provided, and the morbidity of subsequent surgical drainage may be avoided. In other situations, it allows for initial source control and medical stabilization so that an elective one stage operation can be performed. PAD and operative intervention are best viewed as complementary rather than competitive techniques.

Inflammation may manifest as a phlegmon, seen as a viable inflamed mass around the affected tissue, a liquefied abscess, necrotic tissue, or a combination. Liquefied abscesses are drainable, whereas phlegmon and necrotic tissue are not. Decisions regarding which mode of intervention to use are largely based on CT findings and require experience, clinical judgment, and careful consideration of underlying and coexistent disease processes. Close cooperation between the surgeon, interventional radiologist, and other physicians involved in the patient’s care is mandatory.

The basic requirements for catheter drainage include a safe route of percutaneous access and a fluid collection of drainable viscosity. Specific indications for PAD have expanded significantly and now include many conditions that were previously thought undrainable, such as multiple or multiloculated abscesses, abscesses with enteric communication, infected hematomas, and deep pelvic abscesses [54,55]. In fact, for abdominal collections that require drainage, PAD is considered the standard, unless a hard indication for an operation exists [54,55]. Advances in endoluminal ultrasound techniques have facilitated advanced drainage procedures. Those abscesses in contact with the rectum or vagina can be treated with catheter drainage through these organs. These ultrasound-guided transrectal and transvaginal drainage procedures are effective and well tolerated [47,56,57].

It is generally possible to distinguish drainable fluid from phlegmon or necrotic tissue using a combination of imaging and fine-needle aspiration. Not all fluid collections require drainage, but intervention is required for those that are infected and for sterile collections that cause symptoms due to mass effect.

It is important to consider the possibility of underlying neoplastic disease in the setting of enteric perforation, especially in elderly patients. Significant soft tissue thickening of the bowel wall, especially if localized and non-circumferential, should raise the possibility of an underlying tumor, as should the demonstration of potential metastatic disease such as adenopathy or liver lesions. A “target” appearance, with circumferential low-attenuation submucosal thickening sandwiched between the enhancing mucosa and submucosa, is believed to be specific for inflammatory disease. To exclude the possibility of neoplasia fully, follow-up imaging is needed to document resolution, or confirmatory tests such as barium contrast studies or endoscopy can be performed.

Excellent imaging is a key element for successful PAD. Imaging permits precise localization and characterization of disease, appropriate access route planning, and immediate assessment of technical success. Imaging is also needed for adequate follow-up to identify problems and gauge outcome. It is important that the drainage route not cross a sterile fluid collection or other infected space because of the risk of cross-contamination. Crossing the pleural space for thoracic and upper abdominal drainage carries the risk of empyema formation. Thus, collections in the upper abdomen often require an angled subcostal or low intercostal approach [58]. It is acceptable to cross the peritoneal space to drain an extraperitoneal abscess. Placement of a catheter through the small bowel or colon should always be avoided. Transgastric drainage of lesser sac pseudocysts has been advocated by some authors and appears to be safe, although this approach remains controversial [55]. Lesser sac collections also can be approached transhepatically through the left lobe of the liver [59], although traversing solid organs should be avoided whenever possible. Obviously, it is important to be aware of, and avoid, major vascular structures.

In most cases, drainage is performed following fine-needle (18- to 22-gauge) aspiration with the aspirate being used to document infection and gauge the viscosity of the fluid. In some situations, single-step aspiration of the fluid may suffice, without the need for tube placement. Examples include clearly aseptic collections, small abscesses (2 to 3 cm) into which tube placement would be difficult and relatively nonviscous collections that can be completely evacuated. However, for most collections, a drain should be placed to ensure complete evacuation and to minimize the chance of recurrence. If the patient is not already receiving antimicrobial therapy, this should be
instituted before the drainage procedure to minimize the infectious complications of contaminating sterile tissue, although continued antibiotic coverage will be dictated by the contents of the fluid collection.

A multitude of catheters are available for percutaneous insertion. The choice of catheter size is determined primarily by the viscosity of the fluid to be drained. In the majority of cases, 8 to 12 French drains are sufficient [60,61]. Larger drains may be needed for collections that contain debris or more viscous fluid. Drains of larger caliber can be placed at a later time, if needed, by exchange over a guidewire. Although most abscesses can be drained with a single catheter, there should be no hesitation in placing as many drains as are needed to evacuate the abscesses effectively.

After catheter placement, the cavity should be evacuated as completely as possible and irrigated with saline until the fluid is clear. Initial manipulation of the catheter(s) and irrigation should be done as gently as possible to minimize the induction of transient bacteremia and subsequent potential hemodynamic instability. For cavities that are completely evacuated at the initial drainage and for which there are no abnormal communications to viscera, simple gravity drainage generally suffices. For larger or more viscous collections and those with ongoing output due to fistulous connections, suction drainage with sump catheters is more effective [59,61,62]. Thoracic drains should always be placed to water-seal suction to avoid the complication of simple or tension pneumothorax.

Proper catheter management following the initial placement is a critical determinant of success and requires the interventional radiologist to become an active member of the management team [63]. Drains should be checked regularly (at least daily) to monitor the volume and nature of the output, ensure adequate function and clinical response, and quickly recognize and correct any catheter-related problems. Periodic irrigation of the drains is recommended, once or several times per day, with sterile saline [64]. This can be performed by either physicians or trained nurses. Fibrinolytic agents may be useful for evacuation of fibrinous or hemorrhagic collections. Repeat imaging studies and catheter injections are frequently used to document progress and identify problems. Occasionally, it is necessary to add, replace, or reposition drain catheters.

Catheters should be removed when criteria for abscess resolution are met. Clinical criteria of success include resolution of symptoms and indicators of infection. Catheter-related criteria include a decrease in daily drainage to less than 10 mL and a change in the character of the drainage from purulent to serous. Radiographic criteria include abscess resolution and closure of any fistulous communications. If catheters are maintained until these criteria are satisfied, the likelihood of recurrence of the abscess is minimized. For sterile fluid collections, the drain should be removed as soon as possible, generally within 24 to 48 hours, to minimize the risk of superinfection [64].

In evaluating the causes of PAD failure, a number of factors are consistently identified, namely a fluid collection too viscous for drainage and the presence of phlegmon or necrotic debris. Technical modifications such as increasing the drain size and irrigation can salvage some of these drainage procedures. Recognition of phlegmon or necrotic tissue on follow-up imaging studies may lead to cessation of attempts at PAD. Multi-loculated collections and multiple abscesses are another cause of failure that can be minimized by using an adequate number of catheters along with mechanical disruption of adhesions with a guidewire. Fistulous communications, either unrecognized or persistent, are yet another potential cause of failure, as is drainage of a necrotic tumor mistaken by imaging to represent an abscess.

Recognition of a significant soft tissue component, maintenance of a high index of suspicion, and the use of percutaneous biopsies can minimize the risk of failing to appreciate the presence of tumor. Suspicious fluid also can be sent for cytologic assessment. The success rate for PAD tends to be lower in immunocompromised patients (53%) patients, as compared to immunocompetent patients (73%) [65].

Inflammation and infection of the vermiform appendix is the most common intra-abdominal infection requiring surgical intervention [66]. Though the highest incidence is during the first two decades of life, acute appendicitis affects all age groups.

Appendicitis results from obstruction of the appendiceal lumen due to fecalith, lymphadenopathy, foreign body or mass, which initially results in increased luminal pressure, stasis of luminal contents, and soft tissue edema. An intense inflammatory reaction ensues, causing neutrophil infiltration. Venous outflow obstruction develops followed by arterial inflow insufficiency, ultimately resulting in gangrene and perforation.

Classic appendicitis presents with migratory abdominal pain. Initially dull and poorly localized in the periumbilical region, the pain changes to a sharper quality located in the right lower quadrant over McBurney’s point. Anorexia is present early and a mild fever is often present. Nausea and vomiting may also be seen, but if they appear early, before development of pain, suspicion should arise for gastroenteritis. Exam reveals focal peritonitis, often evidenced by rebound tenderness, though a cadre of different signs may be elicited [66]. Leukocytosis, if present at all, is mild. Clinical signs of perforation include intense pain, prolonged symptoms, high fever, significant leukocytosis, tachycardia, and severe tenderness [67].

If the diagnosis cannot be made confidently or if perforation is suspected, contrast enhanced CT scan of the abdomen and pelvis may be ordered and has a 95% positive predictive value for acute appendicitis. CT scan may demonstrate appendiceal dilation and wall thickening, periappendiceal fat stranding, appendicolith, phlegmon, abscess, gross perforation, or free fluid [44,68]. Ultrasound is slightly less reliable for diagnosis and demonstration of complications, but is most useful in evaluating for alternate diagnoses, especially gynecologic disorders [68]. Care should be taken to distinguish periappendiceal changes with those around the terminal ileum that may represent inflammatory bowel disease.

Management is started by early administration of intravenous antibiotics covering against Gram-negative bacteria and anaerobes [69]. In acute non-perforated appendicitis, operative intervention should proceed as quickly as possible. Laparoscopic appendectomy is now the procedure of choice, though in thin males open appendectomy is acceptable. Laparoscopic approach provides superb visualization and allows evaluation of other pelvic and abdominal organs [66]. If perforation is found at laparoscopy, the appendix is resected, irrigation is performed, and antibiotics are continued for an extended course of 7 days.

Periappendiceal masses found on imaging may be a phlegmon or an abscess, representing a contained perforation. If feasible, percutaneous drainage of discrete abscesses is standard. If adequate drainage is achieved, management without appendectomy in the acute setting is safe and effective. Less than 10% of patients will fail this approach and require emergent appendectomy [70].

Current controversy exists concerning the need for interval appendectomy (IA) after initial nonsurgical management. Standard for many years was to perform an IA after a resolution phase of 6 to 8 weeks. IA is often a technically difficult operation due to adhesions and distorted anatomy, and many surgeons will elect not to perform IA. This strategy may be most appropriate, as risk of recurrence of appendicitis or
related complication is low, only 5% to 9% in current studies [69,70,71,72]. Accurate predictors of recurrence are needed. Also of concern is the risk of malignancy. Appendiceal neoplasm is present in 1.7% of surgical specimens [73,74]. In 1.2% of patients managed nonoperatively, a malignancy was discovered at follow up [70]. Careful consideration of the patient’s physiologic status and risk factors must be made.

Diverticulitis is an inflammation of colonic diverticula, while these are actually pseudodiverticula – small herniations of colonic mucosa and submucosa through the muscularis [75]. Diverticula develop from a combination of increased intracolonic pressure and mural weakness at the site of blood vessel penetration into the colon [76,77]. The diverticula become occluded with fecal matter. Local ischemia and bacterial overgrowth result in microperforation and the start of the inflammatory cascade [29].

Diverticulitis presents as a constellation of signs and symptoms, most commonly a triad of fever, lower abdominal pain, and leukocytosis. It is typically a disease of older patients, and very rare in patients younger than 40 [78]. Patients also report constipation, recent hematochezia, nausea, vomiting, and dysuria. Pneumaturia and fecaluria are rare, but indicate colovesicular fistula [79]. Diverticulitis is primarily a clinical diagnosis, but contrast enhanced CT is usually performed to assess the location and severity of disease. CT shows colonic wall thickening and fat stranding around an area with diverticula [80]. Masses, fistulas, abscesses, and perforation may also be visualized.

Management is based upon severity of symptoms, number of recurrences, and presence of any complications of diverticulitis. For those with minor symptoms, oral antibiotics can be given, with a gentle resumption of a regular diet. Complicated disease is defined as having a pericolic or pelvic abscess, fistula, stricture, obstruction, hemorrhage, perforation, or diffuse peritonitis [29,81]. For those with complicated diverticulitis, with more severe symptoms or with signs of systemic inflammation, hospital admission, bowel rest, and parenteral antibiotics are mandated after immediate fluid resuscitation [79]. Length of therapy is variable, but usually is continued until leukocytosis is improved, the patient is afebrile, and has decreased abdominal tenderness [29,75,79].