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preparation is generally recommended within the first 24 hours of admission for patients with LGIB.
If the patient is not stable enough for endoscopic evaluation, radiologic evaluation or surgical intervention should be considered as an alternative. Colonoscopy should also be deferred if there is sus­picion for active diverticulitis as this reportedly increases the risk of perforation. Other procedural risks include mucosal injury and the general risks of anesthesia/sedation.
Computed Tomographic Angiography
Computed tomographic angiography (CTA) is an important diag­nostic tool for the evaluation of active LGIB. The study is performed using intravenous contrast timed such that active arterial extravasa­tion from a vessel into the lumen of the small bowel can be visualized on a multidetector helical CT scanner. Extravasation of intravenous contrast into the lumen of the bowel, or an active “blush,” constitutes a positive finding (Fig. 3). This study has a sensitivity close to 90% and can detect bleeding rates as low as 0.3 mL/min to 0.5 mL/min. Localization accuracy is as high as 97% in patients with high trans­fusion requirements and/or hemodynamic instability. Unfortunately, CTA has a relatively low specificity of 85%.
CTA is widely available, fast, minimally invasive, and does not require any bowel preparation or oral contrast administration. As a result, it is very useful in hemodynamically unstable patients who do not have time to undergo bowel preparation before intervention and are transiently responding to resuscitation. CTA is also useful in identifying other causes of LGIB such as ischemic colitis and can be used to evaluate the small bowel. Disadvantages include the requi­site for active hemorrhage at the time of the study, possible allergic reaction to intravenous contrast, radiation exposure, difficulty with precise localization of a small-intestinal source, and lack of direct therapeutic application.
Nuclear Scintigraphy with Technetium-99m
Like CTA, nuclear scintigraphy allows for radiographic location of LGIB and is purely a diagnostic test. The patient’s red blood cells are tagged with the radiotracer Technetium-99m ( into the patient followed by sequential imaging. Nuclear scintigraphy is a far more sensitive test than CTA as it can detect bleeding rates as
FIG. 3 Active extravasation of contrast in the hepatic flexure of a patient
with lower gastrointestinal bleeding identified by CTA. (Courtesy Michael F Petroziello, MD, Roswell Park Cancer Institute Hospital, Buffalo, NY.)
99m
Tc) and re-injected
low as 0.1 mL/min. An important advantage of this study is its abil­ity to detect bleeding occurring up to 24 hours after tracer injection as the radio-labeled red blood cells remain detectable. The half-life
99m
of
Tc allows for sequential imaging several times in a 24-hour
period.
Despite the high sensitivity rates, nuclear scintigraphy results in false localization rates approaching 25% have been reported, making it less accurate than CTA. This study is best suited as a screening tool for hemodynamically stable patients with scant, intermittent bleeding and not for definitive localization. Arteriography is gen­erally warranted in the event of a positive study for localization and possible therapeutic intervention. Surgical intervention, particularly segmental resection, should not be guided by the results of nuclear scintigraphy.
Angiography
Angiography offers the advantages of accurate localization and the opportunity for therapeutic intervention, and it is a particularly useful option in patients with unstable vital signs requiring ongo­ing blood transfusions. Appropriate indications include copious bleeding precluding colonoscopic evaluation and positive extrava­sation on CTA or nuclear scintigraphy. For the latter, angiography further localizes the source of bleeding and potentially allows for hemorrhage control. These patients require little to no sedation, and access is usually obtained through the femoral artery. Fluoroscopic visualization is used to identify extravasation following selective mesenteric arterial cannulation and injection of contrast material. Angiography can detect bleeding at rates as low as 0.5 mL/min and has a high sensitivity for LGIB. Overall, it is a better test for patients with profuse, active bleeding than for those with scant, intermittent bleeding.
Embolization can be attempted for patients with positive localiza­tion during angiography. Super subselection with microcatheters and microcoil embolization are preferred when possible. Embolization, including highly selective embolization, is clinically successful in the majority of cases, with demonstrated bleeding resolution rates of 75% to 90%, depending on the location (Fig. 4). Other thera­peutic options include intraarterial infusion with vasopressin, a potent vasoconstrictor, which is effective in substantially decreasing bleeding. These maneuvers may eliminate the need for emergent operation and facilitate continued resuscitation followed by surgi­cal intervention under more controlled circumstances. For cases of venous bleeding, embolization of the venous system is possible, though not frequently undertaken.
Many have advocated for the preferential use of angiography in frail patients with severe comorbidities for whom an emergent oper­ation would carry a prohibitively high mortality. Angiography is usu­ally reserved for hemodynamically unstable patients or patients with a continued transfusion requirement. Unfortunately, the rebleeding rate is not insignificant and approaches 20% in some studies. Poten­tial risks of angiography include bowel ischemia, contrast allergy or nephropathy, the risks of sedation, pseudoaneurysm, hematoma, and other vascular complications at the access site. Table 2 outlines and compares salient characteristic features of the various radiologic diagnostic and treatment options.
For patients with intermittent, obscure LGIB that has not been identified via other methods, provocative angiography is a technique that can be utilized. During this procedure, a therapeutic dose of anticoagulant is administered with the goal of provoking the bleed­ing lesion into an active hemorrhage so it can be captured on angiog­raphy. The lesion is then embolized in the same fashion as described previously. Systemic anticoagulation is usually achieved with heparin and followed by incremental and selective transcatheter injection of urokinase and a vasodilator, such as nicardipine. Multiple studies have shown that this procedure has an acceptable risk profile, includ­ing minimal risk of bleeding complications from the anticoagulant.
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Ai
BCiD
ii ii
Ei ii iiFi
FIG. 4 Bleeding at the hepatic flexure of the colon secondary to diverticulosis in two patients. Multiplanar reconstruction (MPR) and volume-rendered 3D
reconstruction of arterial-phase CT images reveal arterial bleeding from the peripheral branch of the right colic artery (A and B) and the middle colic artery (C and D). Pre- and postembolization images demonstrate extravasation of contrast from the involved vessels and resolution of bleeding, respectively (E and F). (From Tsurukiri J, Ueno M, Kaneko N. Bleeding at the hepatic flexure of the colon secondary to diverticulosis. Clin Gastroenterol Hepatol. 2012;10:e11–e12.)
TABLE 2 Radiologic Imaging Tests for Evaluation of Lower Gastrointestinal Bleeding with Their Associated
Characteristics
Bleeding Detection Rate
Study Invasive Procedure
(mL/min)
Localization Intervention
CTA 0.3–0.5 + – NS 0.1 – Angiography + 0.5 + +
CTA, Computed tomographic angiography; NS, nuclear scintigraphy.
Nearly one-third of patients with a previously unidentified source of LGIB have a source identified with provocative angiography. Bleeding lesions can be treated by embolization or surgical resection. Resection is the preferred treatment for hypervascular neoplasms and can be useful for selected patients with angiodysplasia. If surgical resection is being considered and no mass lesion is identified at the time of selective arteriography, a microcatheter should be left in the feeding artery. The patient should be brought to the operating room in an expeditious fashion for surgical exploration. Injection of the catheter with blue dye will allow for visualization of the involved segment and can be used to guide the extent of resection.
Capsule Endoscopy
Although the majority of LGIB is colonic in origin, some cases of obscure bleeding originate from the small bowel. Capsule endoscopy is a useful modality for the subset of patients who have persistent
bleeding and negative endoscopic evaluations of the colon and fore­gut. The patient swallows a pill-sized capsule that contains a small camera. The camera takes intermittent photographs as it travels through the patient’s GI tract, and the photos are retrieved after the capsule is returned. The images are reviewed carefully to determine the source of bleeding. Capsule endoscopy is therefore best suited for hemodynamically normal patients who have chronic GI bleed­ing with a suspected small intestinal source. Diagnostic accuracy is good with sensitivities and specificities of approximately 90% and 95%, respectively. Diagnostic yield is improved in patients with acute bleeding and in those taking anticoagulants. The procedure is noninvasive and has an overall low complication rate; however, complications may include battery failure, capsule retention, and bowel perforation. Other disadvantages include the lack of poten­tial for localization or therapeutic intervention. Patients may be administered a test capsule made of absorbable material before the
Capacity for
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actual pill camera if the patient is at high risk for a retained capsule. Surgical intervention is required for retained capsules but may result in accurate identification and treatment of the bleeding pathology in rare circumstances.
Double Balloon Enteroscopy
Similar to capsule endoscopy, double balloon enteroscopy allows for visualization of the small bowel. The study is performed under anesthesia/sedation. An endoscope is utilized with the addition of an overtube. Both the endoscope and overtube have balloons at their distal aspects. The procedure begins like any other endoscopy, and the endoscope is advanced into the proximal small bowel. The overtube balloon is then inflated and the overtube retracted, thus pulling the small bowel toward the endoscope and allowing the latter to advance further into the small bowel. To pass further, the endoscope’s balloon is inflated, and the overtube’s balloon deflated advancing it forward to meet the endoscope. This tedious process allows the endoscope to advance though the small bowel as a result of retraction of the overtube.
Hemodynamically stable
Frequently, patients have already undergone CTA or capsule endos­copy to identify an area of interest. The major advantages over capsule endoscopy include the potential for therapeutic intervention and tissue sampling. In addition, double balloon endoscopy can be performed via the transoral or transanal routes. Disadvantages include the risk of bowel perforation and the risks associated with anesthesia as well as prolonged duration of the procedures, often lasting 60 to 90 minutes.
Management Algorithm for LGIB
Further management of the patient presenting with LGIB depends on the results of the aforementioned localization studies. A treat­ment algorithm is proposed to guide management for these complex patients (Fig. 5). We recommend colonoscopy as a first-line test for stable patients with mild or moderate LGIB. Many of these patients will have diverticular bleeding, and this has been shown to resolve spontaneously in 80% of cases, with most patients receiving fewer than 4 units of blood. This is irrespective of colonoscopic interven­tion. Up to one-third of spontaneously resolving diverticular bleeds
Lower Gl Bleeding
Hemodynamically unstable
Occult LGIB
Outpatient
Colonoscopy
No
Consider alternate studies:
CTA if active bleeding
Nuclear scinigraphy if intermittent
EGD if upper GI source likely
Provoked angiography
Capsule endoscopy
Source
identified?
Moderate LGIB
Transfuse as
indicated
Urgent
colonoscopy
YES
Treat source
all studies negative
YES
YES
TRANSIENT
Resuscitate: Tranfuse as indicated Correct coagulopathy
Responsive to blood
products?
Stat CTA
IR consultation
Source
identified?
No
Surgery
No
FIG. 5 Algorithm for the management of lower gastrointestinal bleeding. CTA, Computed tomography angiography; EGD, endoscopy; GI, gastrointestinal; IR,
interventional radiology LGIB, lower gastrointestinal bleeding.
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will recur within 6 to 12 months. Other forms of LGIB will also spontaneously resolve at high rates, including angiodysplasias, the most common cause of obscure LGIB. These may also recur at rates nearing 50% within 1 year. Although observation and serial hemo­globin monitoring may be an acceptable monitoring plan in some patients, therapeutic intervention with endoscopic or interventional techniques is preferred by surgeons whenever possible.
In patients with massive LGIB or moderate LGIB with instabil­ity, emergent CTA should be performed if the patient transiently responds to blood transfusion. Early notification of the interventional radiology team for possible angiography with embolization is crucial in the critically ill patient, and CTA can be bypassed altogether if the patient is increasingly unstable with minimal response to blood transfusion. Emergent esophagogastroduodenoscopy (EGD) should be considered if an upper GI source is suspected based on the history and physical examination. Aggressive resuscitation in a critical care setting along with reversal of coagulopathy and appropriate transfu­sion should be performed concurrently.
Emergent surgical intervention is a last resort in the manage­ment of LGIB because of high mortality rates but can be necessary and life-saving for some patients. Consequently, it is important for surgeons to be involved in the management of these patients early in their treatment as patients can decompensate quickly, leaving only a small window of opportunity for optimization. In general, emergent surgery is reserved for hemodynamically unstable patients or for those who have undergone failed interventions.
SURGICAL CONSIDERATIONS
Indications
Improvements in endoscopic and interventional radiology hemo­static techniques during recent years has resulted in a decreased role for emergent surgical intervention in patients with LGIB. Current indications for emergency surgical management are limited to failure of nonoperative intervention with a confirmed or presumed source and ongoing bleeding or hemodynamic instability, particularly in patients who have received transfusion of more than 6 units of blood products. In a hemodynamically stable patient, nonurgent surgical intervention may also be warranted in select cases, such as malig­nancy, bleeding hemorrhoids, or Meckel’s diverticulum.
Operative Technique
Operative planning relies heavily on localization of the bleeding source and stability of the patient. For most patients with a presumed colonic source, surgical options include either a segmental resection or a subtotal colectomy. For patients with bleeding that cannot be controlled endoscopically, one consideration is to have the endos­copist tattoo the segment to facilitate intraoperative identification, which is an otherwise a difficult task.
Localization of the bleeding lesion before surgery is helpful to prevent excess mortality from a subtotal colectomy. In most studies, the mortality from this procedure approaches 40%, whereas segmen­tal resection carries only a 20% mortality risk. Additionally, localiza­tion ensures that rebleeding from an unresected lesion is prevented. In contrast with the mortality risk, subtotal colectomy carries only a
4% risk of rebleeding, whereas segmental resection has a close to 20% risk. These risks and benefits should be considered on an individual basis with the understanding that the primary goal of surgery is to provide immediate control of the bleeding. If there is any question at all about localization, the surgeon should strongly consider perform­ing a subtotal colectomy.
Patients requiring emergent colectomy for acute LGIB are at high risk for morbidity and mortality, with close to 60% suffering compli­cations such as respiratory or renal failure. The surgeon should have a low threshold to perform a damage-control operation and delay formal closure of the abdomen. This will allow for ongoing resusci­tation of the patient and monitoring for ongoing bleeding in a critical care setting. Temporarily packing the abdomen with laparotomy sponges can be considered for coagulopathic patients with diffuse hemorrhage from surgical surfaces to minimize time in the operating room. The patient can be returned to the operating room in 24 to 48 hours for reexploration and formal closure. The decision whether to create an ostomy or reconstruct the GI tract with an anastomosis can be made at that time. Since an anastomotic leak can be catastrophic, the creation of an anastomosis at the time of initial emergent surgery in the setting of coagulopathy and hemodynamic instability should be discouraged.
CONCLUSION
LGIB is a heterogeneous disease state consisting of a broad differ­ential diagnosis with a range of severity. Owing to this complexity, a thorough history and physical examination is most important to narrow the differential diagnosis and proceed through a thoughtful diagnostic algorithm. Resuscitation, correction of coagulopathy, and blood transfusion are the cornerstones of management of LGIB and are often the only therapeutic maneuvers necessary given that most patients presenting with LGIB will spontaneously resolve. Endo­scopic and interventional radiology procedures should be the initial localization and therapeutic modalities for most patients with LGIB depending on the clinical status of the patient. Surgery is reserved for a small subset of patients with continued hemodynamic instability or failure of less-invasive techniques, but it can be life-saving. Surgeons should be actively engaged in the management of patients with LGIB and should be prepared to intervene in the rare circumstance that this becomes necessary.
S u g g e S t e d R e a d i n g S
Gralnek IM, Neeman Z, Strate LL. Acute lower gastrointestinal bleeding. N
Engl J Med. 2017;376:1054–1063.
Jacovides CL, Nadolski G, Allen SR, etal. arteriography for lower gastroin-
testinal hemorrhage: role of preceding abdominal computed tomographic
angiogram in diagnosis and localization. JAMA Surg. 2015;150:650–656. Lau JYW, Yu Y, Tang RSY, etal. Timing of endoscopy for acute upper gastro-
intestinal bleeding. N Engl J Med. 2020;382:1299–1308. Oakland K, Chadwick G, East JE, etal. Diagnosis and management of acute
lower gastrointestinal bleeding: guidelines from the British Society of
Gastroenterology. Gut. 2019;68:776–789. Oakland K, Jairath V, Uberoi R, etal. Derivation and validation of a novel
risk score for safe discharge after acute lower gastrointestinal bleeding: a
modelling study. Lancet Gastroenterol Hepatol. 2017;2:635–643.
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Appendicitis: Diagnosis and Management
Elaa Mahdi, MD, MPH, and Walter Pegoli Jr., MD
ppendicitis continues to be one of the most common causes of the acute surgical abdomen treated by general surgeons. The
A
global incidence of appendicitis ranges from 100 to 150 per 100,000 persons per year, with a lifetime risk of 7% to 10%. In the United States, there are about 400,000 cases diagnosed each year, of which 16% to 40% are perforated. The pathogenesis of appendicitis remains unclear, with the thought being that obstruction of the appendiceal lumen results in inflammation and bacterial infection. The diag­nosis is made on patient history, physical examination, laboratory tests, and various imaging modalities. Traditionally, treatment has included the initiation of antibiotics followed by surgical resection of the appendix. However, recent studies have demonstrated efficacy for the treatment of uncomplicated appendicitis using antibiotics alone. In this chapter, we discuss the pathophysiology, diagnostic workup, and most recent recommendations regarding management of patients with appendicitis.
ANATOMY OF THE APPENDIX
The appendix is an approximately 9 cm long and 0.6 cm wide ver­miform or “worm-shaped” hollow viscus structure originating from the terminal cecum, where the three taenia coli converge. Upon completion of normal antenatal rotation of the intestine, the cecum and appendix are typically found in the right lower quadrant (RLQ). However, their location can be varied in patients with nonrotation or malrotation of their intestines. Although the base of the appen­dix always emanates from the cecum, the location of the tip of the appendix is often more variable (Fig. 1). It can be found retrocecal, subcecal, pelvic, preileal, or postileal, accounting for the diversity of presenting signs and symptoms. The blood supply to the appendix and mesoappendix is from the appendiceal artery, a branch off the ileocolic artery.
Taenia coli
0.5% Postileal
1% Preileal
PATHOLOGY OF ACUTE APPENDICITIS
The etiology of acute appendicitis is thought to be caused by obstruc­tion of the appendiceal lumen. The most common cause of luminal obstruction is mechanical obstruction from a fecalith or appendicolith. Other causes include lymphoid hyperplasia, parasitic infections, neo­plasm, or a foreign body. If left untreated, the ongoing obstruction results in a cycle of increased bacterial overgrowth, mucus production, inflammation, and venous congestion. The subsequent distension of the normally narrow-caliber appendix causes stretching of the visceral affer­ent nerve fibers, resulting in the vague periumbilical abdominal pain that is often described as one of the first symptoms. Similarly, distension of the appendix can result in nausea and vomiting early in the course of the disease. The increasing congestion eventually leads to obstruction of arte­rial inflow, resulting in ischemia, with progression to necrosis, gangrene, and eventually perforation with or without abscess formation. Organisms isolated in patients with acute appendicitis include Escherichiacoli, Bac-
teroidesfragilis, Klebsiella pneumoniae, Streptococcus, Enterococcus, and Pseudomonas aeruginosa. In cases of gangrenous or perforated appen-
dicitis, E. coli and Bacteroides spp. are found in a majority of patients. Knowing the most common bacterial culprits helps guide antibiotic management in the treatment of appendicitis, especially if a nonoperative approach is chosen or postoperative antibiotics are required.
CLINICAL PRESENTATION AND DIAGNOSTIC WORKUP
History and Physical Examination
The diagnosis of appendicitis has typically been a clinical diagno­sis based on history and physical examination. Patients will often complain of a vague onset of symptoms including anorexia, malaise, and epigastric or periumbilical abdominal pain/discomfort. This will typically progress to nausea and/or vomiting associated with abdominal pain that migrates to the RLQ. Findings on physical examination include fever, tachycardia, RLQ tenderness, guarding, and percussion tenderness. The tenderness usually is most intense at McBurney’s point, which is located one-third of the distance between the right anterior superior iliac spine and the umbilicus. The patient may exhibit a positive Rovsing’s sign, which is defined as palpation of the left lower quadrant (LLQ) resulting in RLQ pain. Additionally, physical examination findings will differ based on the location of the appendiceal tip and the degree of inflammation. A patient with a retrocecal appendix may not present with RLQ pain, but will have a positive psoas sign when extension of the right hip produces pain. A patient with a pelvic appendix may have an obturator sign, when internal rotation of the right hip causes pain. However, recent data suggest that although these signs are specific, they are not very sen­sitive for diagnosing acute appendicitis (Tables 1 and 2). Multiple
TABLE 1 Clinical Signs and Symptoms of Acute
Appendicitis
64%
Retrocecal
FIG. 1 Variations in the positions of the vermiform appendix.
Terminal ileum
2% Pelvic
32% Subcecal
History Onset of vague abdominal discomfort, cramp-
ing, nausea, progressing to right lower quadrant pain, with associated anorexia, vomiting, and general malaise
Physical
examination
Laboratory
examination
Diagnostic
imaging
Right lower quadrant tenderness, voluntary
and involuntary guarding, fever, tachycardia, occasionally palpable mass
Leukocytosis, No bacteria on urinalysis, nega-
tive pregnancy testing
Distended fluid-filled appendix with surrounding
inflammation, perforation, abscess, fecalith
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TABLE 2 Clinical Examination Operating
Characteristics for Diagnosis of Acute Appendicitis
Sensitivity (%) Specificity (%)
Rovsing’s sign 30–68 58–91 Obturator sign 21–34 79–96 Psoas sign 16–39 50–95
TABLE 3 Pediatric Appendicitis Score Variables
Sign/Symptom Score
Nausea/vomiting 1 Anorexia 1 Fever (≥38.0 C) 1 Migration of pain 1 Leukocytosis (WBC >10,000 mm3) 1 Neutrophilia (>75%) 1 Right lower quadrant pain 2 Tenderness with hopping/coughing/percussion 2 Tota l 10
WBC, White blood cell.
clinical scoring systems have been developed to aid in the diagnosis of appendicitis. The Appendicitis Inflammatory Response (AIR) and the Alvarado score are used in adults, with the AIR found to have the superior performance. In children, the Pediatric Appendicitis Score (PAS) was developed to help identify patients with appendicitis using eight signs, symptoms, and laboratory values often associated with appendicitis (Table 3).
However, even when a patient presents with the “classic” signs and symptoms of appendicitis, a broad differential diagnosis includ­ing inflammatory bowel disease, urinary stones, Meckel’s diverticuli­tis, and other potential etiologies should also be considered.
Laboratory Examination
On laboratory examination, patients are typically found to have a leukocytosis (>10,000 cells/mm and elevated markers of inflammation such as C-reactive protein (CRP). Although these are nonspecific findings of appendicitis, a normal laboratory value for them is less likely to be indicative of appendicitis. A urinalysis should be obtained to evaluate for a possible urologic source. Of note, sterile pyuria can result from the proximity of an inflamed appendix to the bladder.
3
), a left shift (>75% neutrophilia),
Diagnostic Imaging
Different imaging modalities can be used to assist in the diagnosis of acute appendicitis, depending on patient age, body habitus, and risk of radiation exposure. In the pediatric patient, ultrasound (US) remains the initial imaging study of choice. It is easy to perform, inexpensive, and does not expose patients to harmful radiation. However, it is user-dependent and has limited visualization in obese patients. The overall specificity is 83% and sensitivity is 78%. Ultrasound findings typically include a distended, noncompressible appendix >6 mm in diameter with hypervascularity on Doppler studies (Fig. 2). Computed tomography (CT) is the most widely used study in the adult population. It is quick, not user-dependent, and
has a specificity of 90% and sensitivity of 94%. However, it is more expensive than US and exposes patients to ionizing radiation. Of note, when used in children, low-dose radiation techniques should be utilized. Findings typically include a distended, fluid-filled appen­dix, periappendiceal fat stranding, and appendicoliths when present (Fig. 3). It can also demonstrate free fluid, abscess, phlegmon, and other findings associated with complicated appendicitis. In addi­tion, colitis, diverticulitis, inflammatory bowel disease, gynecologic pathology, and other maladies in the differential diagnoses can be elucidated by CT. Magnetic resonance imaging (MRI) is gaining pop­ularity as an imaging modality in children and in pregnant women. The diagnostic accuracy is similar to CT, without the exposure to ionizing radiation. However, it is associated with increased cost com­pared with CT. In their meta-analysis of second-line imaging after equivocal initial US, Eng et al. reported pooled MRI sensitivities and specificities of 97.4% and 97.1% in children, and 89.9% and 93.6% in adults, respectively. MRI is a viable alternative to CT in children or pregnant women with inconclusive findings on US.
MANAGEMENT OF ACUTE APPENDICITIS
The management of acute appendicitis has continued to evolve over time. Whereas the diagnosis of acute appendicitis would have traditionally meant the initiation of antibiotics and an emergent trip to the operating room, more recently the trend has been to delay surgical intervention until convenient for up to 24 hours. Some practitioners are now even managing patients with uncomplicated appendicitis nonoperatively using antibiotics alone.
Once the diagnosis of appendicitis has been made, patients should be resuscitated with intravenous crystalloid fluids (if nec­essary) and started on broad-spectrum intravenous antibiotics with gram-negative and anaerobic coverage as some of the most common organisms associated with acute appendicitis are E. coli, B. fragilis, and K. pneumoniae. Popular broad-spectrum antibiotics include piperacillin-tazobactam, ampicillin-sulbactam, and imipe­nem-cilastatin. Alternative antibiotics include ceftriaxone-metro­nidazole or cefoxitin. Cameron et al. compared the effectiveness of extended-spectrum antibiotics (piperacillin-tazobactam) versus narrow-spectrum antibiotics (cefoxitin or ceftriaxone-metronida­zole) on rate of surgical site infections and hospital readmission rates in children with uncomplicated appendicitis. They found no difference in the outcomes, supporting the use of narrow-spectrum antibiotics in an era of increasing incidence of antibiotic-resistant bacteria. The duration of antibiotic therapy should be dependent on the severity of disease and whether the patient undergoes an appendectomy. For those with uncomplicated appendicitis who undergo appendectomy, antibiotics need not be continued postop­eratively. Patients with complicated appendicitis will require a lon­ger course of antibiotic therapy predicated upon extent of disease and clinical condition.
Timing of Surgery
The diagnosis of uncomplicated appendicitis is no longer consid­ered an acute surgical emergency. Van Dijk et al. found no signifi­cantly higher risk for developing complicated appendicitis when surgery was delayed for up to 24 hours from hospital presentation. Data from the National Surgical Quality Improvement Program (NSQIP) reported similar outcomes, even when appendectomy was delayed until hospital day 2. However, those who underwent appendectomy on hospital day 3 had increased 30-day mortality and major postoperative complications. The WSES Jerusalem 2020 guidelines recommend operating within 24 hours of presentation in children and adults with uncomplicated acute appendicitis. In addition, they state that in pregnant patients with equivocal findings, a short in-hospital delay with repeat abdominal US is acceptable without a significant increased risk of adverse maternal or fetal outcomes.
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*
A
*
C
FIG. 2 Ultrasound images of appendicitis. (A) Noncompressed appendix
with surrounding free fluid (asterisk). (B) Compressed appendix with failure to change the luminal diameter compared with the noncompressed appendix in A. (C) Fecalith with a target appearance. (D) Color Doppler can evaluate for the presence or absence of blood flow within the wall of an inflamed appen­dix. (E) Dilated appendix. (Images courtesy Dr. Katherine Kaproth-Joslin.)
B
D
1
+
+
E
*
*
FIG. 3 CT images of appendicitis. (A) Dilated appendix (arrow).(B) Appendicolith (arrow). (Images courtesy Dr. Katherine Kaproth-Joslin.)
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Laparoscopic Appendectomy
The patient is placed in the supine position on the operating table with the left arm or both arms tucked. A Foley catheter should be considered if the patient was not confirmed to have voided before the case. The patient is prepped from the xiphoid process to the pubis. The abdomen is accessed through the umbilicus either with an open technique using a Hasson trocar or closed technique with a Veress needle. For placement of the Veress needle, the umbilicus is elevated with two towel clips, and an incision is made through the skin. The Veress needle is inserted perpendicular to the skin and advanced until two audible clicks as the spring-loaded needle retracts are appreciated. The first click occurs as the needle transverses the fascia, and the second click occurs as the needle transverses the peritoneum. A saline drop test is then performed to confirm entry into the peritoneal cavity. The abdomen is insufflated with carbon dioxide until intraabdominal pressure is 12 to 15 mm Hg. The Veress needle is retracted, followed by either a blind entry with a 12-mm closed conventional trocar or radially expanding trocar ver­sus visual entry with an optical trocar (Optiview, Visiport). For the Hasson open technique, an incision is made into the infraumbilical or supraumbilical fold and carried through the subcutaneous tissue. Dissection is then performed through the subcutaneous tissue with S-retractors or a Kelly clamp until the rectus fascia is visualized. Two retention sutures are placed into the fascia on either side of the midline. With a knife, scissors, or electrocautery, a vertical incision is made through the fascia elevated with the retention sutures. The peritoneal cavity is entered bluntly with a Kelly clamp. The Hasson port is inserted under direct visualization and anchored in place with the stay sutures. The abdomen is insufflated and inspected to ensure that no injury occurred during entrance. The placement of subsequent trocars can be variable, depending on patient size, age, and pregnancy (Fig. 4). However, our preference is the use of an umbilical camera port and the working 5-mm ports at the right upper quadrant and LLQ (see Fig. 4A). A four-quadrant exploration is first done to quickly rule out other intraabdominal abnormalities before the patient is placed in reverse Trendelenburg with the right side up. Atraumatic graspers are used to follow the cecum to the con­vergence of the taenia coli. The cecum is lifted toward the left upper quadrant to better expose the base of the appendix. The mesoappen­dix is grasped/elevated, and peritoneal and/or omental attachments are lysed to expose the entirety of the appendix. For the retrocecal appendix, the white line of Toldt must be divided to mobilize the cecum and expose the appendix. A window is created through the mesoappendix. A linear gastrointestinal endoscopic stapler with a white load or an electrosurgical device (cautery or LigaSure) is intro­duced through the umbilical port, and the mesoappendix is divided, leaving the base of the appendix exposed (Fig. 5A). A blue load on the stapler is then used to divide the appendix (Fig. 5B; Fig. 6). Of note, an Endoloop may also be used to control the appendiceal base. The appendix is placed in a retrieval bag and withdrawn through the umbilical port. The staple line is then inspected, and hemostasis is achieved, as necessary. If murky, turbid fluid is observed in the pelvis, consideration should be given to obtaining a sample for Gram stain, culture, and sensitivities. Information gained may influence the choice of postoperative antibiotics. Recent data discourage peri­toneal irrigation as it shows no benefit and may lead to an increased incidence of postoperative abscess formation. The working ports are removed under direct visualization, followed by desufflation through the umbilical port and closure of the trocar sites.
Open Appendectomy
Although the laparoscopic approach to appendectomy is most commonly used, the ability to perform an open appendectomy is essential. The patient is placed in the supine position and prepped in the usual sterile fashion. An imaginary line is drawn between the anterior superior iliac spine (ASIS) and the umbilicus. McBurney’s point is identified and marked (see Fig. 4D). A skin incision is
made within a natural crease. The dissection is carried down to the external oblique aponeurosis. The muscle is incised in the direction of its fibers and spread bluntly to expose the underlying internal oblique muscle. It too is dissected similarly to expose the transversus abdominis, which is split to expose the peritoneum. The peritoneum is elevated and sharply incised with care taken to avoid injury to the underlying bowel.
Once inside the abdomen, the cecum is identified and elevated into the wound. The appendiceal base is located at the confluence of the tenia. The appendix is dissected free from surrounding structures. A stapling device can be used to ligate/divide the mesoappendix and the appendiceal base. The “classic” technique divides the mesoappendix between Kelly clamps and ligating the ends using 3-0 silk. The base of the appendix is crushed with a Kelly clamp. The clamp is then relocated on the appendix 1 cm distal to the crushed zone (CZ). The appendix is ligated at the CZ with an 0 Chromic suture. The appendix is divided just proximal to the clamp. The stump may be cauterized or invaginated with a purse-string suture or a Z-stitch.
The incision is closed in layers. First, the peritoneum and trans­versus abdominis are closed with a running absorbable suture. Next, the internal and external oblique muscles are anatomically approxi­mated with interrupted absorbable sutures. Finally, the skin is closed with a running absorbable subcuticular suture. In the case of perfo­ration, the skin may be left open or loosely approximated.
Management of Perforated (Complicated) Appendicitis
Perforated appendicitis occurs in up to 40% of cases of appendicitis. Such patients will usually have had a longer duration of symptoms before presentation. The findings on abdominal examination may range from a tender RLQ abdominal mass to a rigid distended abdomen with diffuse peritonitis. Imaging findings may range from pneumoperitoneum and free fluid to an RLQ phlegmon or abscess. Patients diagnosed with complicated appendicitis should be resuscitated with intravenous fluids and immediately started on intravenous antibiotics such as piperacillin-tazobactam alone or a ceftriaxone with metronidazole. The decision to proceed with surgical intervention will depend on their clinical picture. Patients who are diffusely peritonitic and hemodynamically unstable should be aggressively resuscitated and taken to the operating room when adequately resuscitated. Patients who are found to have phlegmon or abscess formation can be considered for nonoperative management, which consists of intravenous antibiotics, percutaneous drainage (for patients with a drainable collection), and nutritional support for those who are unable to aliment orally. Appendectomy in the setting of an abscess or phlegmon is technically challenging and has been associated with a higher incidence of intraoperative and postopera­tive complications. Antibiotic therapy should be dictated by culture results, if available. Once patients are tolerating a regular diet, they can be transitioned to oral amoxicillin/clavulanate (Augmentin) for a total 5-day course, which has been shown to be as efficacious as 7 days of antibiotics, with no increase in the risk of abscess formation.
CURRENT CONTROVERIES
Nonoperative Management of Nonperforated Appendicitis
Although appendectomy remains the treatment of choice in patients with uncomplicated acute appendicitis, nonoperative management with antibiotics has become a viable alternative. O’Leary et al. per­formed a randomized clinical trial comparing the efficacy of antibi­otic only versus appendectomy in uncomplicated acute appendicitis. They found that 25% of their antibiotic-only group experienced recurrence within 1 year. Of note, the antibiotic-only group also reported a decreased quality of life when compared with the surgical cohort. They concluded that surgery remains the mainstay of treat­ment. In their randomized clinical trial, the CODA Collaborative
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FIG. 4 Laparoscopic and open incisions for appendectomy. (A) Umbilical port (A), RUQ port (B), and LLQ port (C). (B) Umbilical port (A), RUQ port (B),
and suprapubic port (C). (C) Umbilical port (A), suprapubic port (B), and LLQ port (C). (D) McBurney’s point one third the distance from the ASIS and umbilicus, with a surgical incision made over McBurney’s point in a natural skin crease. LLQ, Left lower quadrant; RUQ, right upper quadrant.
compared a 10-day antibiotic course verses appendectomy at 25 centers in the United States. They found that although antibiotics were not inferior to appendectomy for the 30-day health status, the antibiotic-only group had higher failure rates, with 29% undergoing appendectomy by 90 days (41% of those with appendicolith and 25% of without appendicolith). Of note, most recent studies have shown a
5-year recurrence rate approaching 50% in both children and adults who were treated with antibiotics alone. Careful patient selection must be utilized in selecting which patient is an appropriate candi­date for nonoperative management. Appropriate candidates should have a small appendix that does not contain an appendicolith on diagnostic imaging, CRP < 60 g/L, WBC < 12, and age < 60 years to
286 APPENDICITIS: DIAGNOSIS AND MANAGEMENT
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FIG. 5 (A) A window is created in the mesoappendix between the base of the appendix and the cecum, and the mesoappendix is divided with a white,
vascular load. (B) The base of the appendix is stapled and divided with a blue gastrointestinal staple load.
and required appendectomy within 1 year, with a morbidity rate of 6%. Of note, the performance of interval appendectomy is often driven by parental concerns.
FIG. 6 The base of the appendix is stapled and divided.
have a chance of successful recovery based on studies by Hansson et al. and Loftus et al. Antibiotic duration for these patients ranges from 7 to 10 total days, with transition from intravenous to oral antibiotics following clinical improvement.
Interval Appendectomy
Interval appendectomy in patients who underwent initial nonoper­ative management of complicated appendicitis remains a controver­sial subject. It is typically considered safe to perform 6 weeks after successful treatment, as the acute inflammatory process has resolved by that time. Some argue that such patients have a very low rate of recurrence after their initial presentation and that surgery, with its 11% complication rate, is unnecessary. Proponents of interval appen­dectomy argue that there is a significant rate of recurrence and stress the importance of excluding an underlying appendiceal malignancy. At present, there is still no strong evidence to recommend for or against it in adults. However, it is recommended that adults 40 years of age and older undergo interval CT and colonoscopy to rule out malignancy. In children, several studies have shown that interval appendectomy is indicated. A 2017 multicenter randomized study found that 23% of children initially treated nonoperatively recurred
SUMMARY
Acute appendicitis continues to be a common, but complex, diagnos­tic and management challenge to surgeons. The variability in clinical presentation across ages and the broad differentials can cloud the diagnosis. No one clinical finding, laboratory study, or imaging find­ing can reliably make the diagnosis 100% of the time. Surgeons must combine these findings and resources to discern the diagnosis. Even then, the management can be complex and is ever evolving. Preop­erative antibiotics and appendectomy remain the gold standard in the management of uncomplicated cases. In complicated cases, those patients with uncontrolled intraabdominal sepsis should be resusci­tated, given broad-spectrum antibiotics, and taken to the operating room as soon as possible. Controversy exists on how to best treat those patients with complicated appendicitis who are clinically sta­ble. Some clinicians advocate the use of antibiotics with or without percutaneous drainage in those with abscess formation, while others advocate for early surgical intervention. Further studies are needed to delineate which approach is truly superior. For now, all agree that appendicitis still remains a surgical disease.
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