Acute Appendicitis: Appendix Differential Diagnosis and Comprehensive Guide

Introduction

Acute appendicitis, an inflammation of the vermiform appendix, stands as the primary cause of abdominal surgical emergencies across the globe and notably in children. In the United States, it accounts for approximately 300,000 annual hospital visits. Characterized by its rapid onset, patients typically seek medical attention within 24 hours of symptom manifestation. While advancements in antibiotic therapies have emerged, surgery remains the definitive treatment for acute appendicitis. Appendectomy is generally a safe procedure with a low global mortality rate. However, delayed diagnosis or untreated appendicitis can lead to severe complications, including appendiceal perforation, abscess formation, peritonitis, sepsis, and potentially fatal outcomes. The significant impact of acute appendicitis in both pediatric and general surgery highlights the critical need for accurate and timely diagnosis, prompt intervention, and effective management strategies. Understanding the clinical features and nuances of appendicitis is paramount for healthcare professionals to ensure timely and appropriate patient care, thereby minimizing the risk of complications.

Etiology

The primary etiological factor in appendicitis is the obstruction of the appendiceal lumen, which subsequently leads to inflammation. This obstruction can arise from various causes such as appendicoliths, tumors within the appendix, intestinal parasites, or hypertrophy of lymphatic tissues. These mechanical obstructions are crucial in the pathogenesis of acute appendicitis. It is important to recognize that the specific causes of luminal obstruction can vary significantly across different age demographics, necessitating age-specific considerations in the diagnostic and management approaches to appendicitis.

The appendix naturally harbors a diverse bacterial flora, including both aerobic and anaerobic species such as Escherichia coli and Bacteroides spp. Obstruction of the appendiceal lumen, regardless of the cause, can disrupt this balance, leading to bacterial overgrowth. This overgrowth triggers acute inflammation and the potential formation of abscesses. Recent research employing advanced next-generation sequencing has shown that patients with complicated, perforated appendicitis exhibit a considerably higher load of bacterial phyla compared to those with uncomplicated appendicitis. This suggests a correlation between the severity of appendicitis and its complications with an increased abundance of bacterial species, highlighting the role of the microbiome in disease progression.

In pediatric appendicitis, lymphoid hyperplasia is the most frequent cause. This condition involves an excessive proliferation of lymphoid tissue within the appendix, leading to inflammation and localized ischemia. This inflammatory process elevates the risk of appendiceal perforation, the development of periappendiceal abscesses, and subsequent peritonitis. It’s noteworthy that reactive lymphoid hyperplasia is often misdiagnosed as one of the primary etiologies of appendicitis, underscoring the diagnostic challenges in pediatric cases.

In adult patients, acute appendicitis is commonly linked to infections, fecaliths, or tumors. Tumors associated with appendicitis in adults include appendiceal adenocarcinoma, mucocele, and carcinoid tumors, indicating a broader spectrum of underlying causes compared to the pediatric population.

Epidemiology

Acute appendicitis constitutes a significant portion of acute abdominal conditions encountered in healthcare settings. Its incidence rate is estimated to range from 100 to 223 new cases per 100,000 individuals annually. In the United States alone, approximately 300,000 hospital visits are attributed to appendicitis each year, underscoring its prevalence and impact on healthcare resources.

While appendicitis can manifest at any age, it is most prevalent within the 5 to 45 age bracket. This age distribution reflects a higher occurrence during childhood, adolescence, and early adulthood. The average age at presentation is around 28 years. Overall, there is a slight male predominance in acute appendicitis cases compared to females. The lifetime incidence risk is approximately 8.6% for males and 6.7% for females. However, it is essential to recognize that appendicitis affects both sexes, and the difference in incidence is not markedly significant.

Pathophysiology

Appendiceal luminal obstruction, irrespective of its etiology, initiates a cascade of events leading to a rise in both intraluminal and intramural pressure. This pressure increase results in the occlusion of small vessels, thrombosis, and lymphatic stasis. Consequently, the obstructed appendix becomes engorged with mucus, leading to distension. As lymphatic and vascular compromise progresses, the appendiceal wall suffers ischemia and necrosis. Concurrently, bacterial overgrowth occurs within the obstructed lumen. Initially, aerobic organisms dominate in the early stages of appendicitis, but as the disease advances, a mixed flora of aerobic and anaerobic bacteria prevails. Common bacterial species involved include E. coli, Peptostreptococcus, Bacteroides, and Pseudomonas.

As inflammation and necrosis intensify, the appendix becomes vulnerable to perforation, which can result in a localized abscess. In severe instances, this can escalate to peritonitis, representing a significant progression of the disease and increased risk to the patient.

Histopathology

A key microscopic finding in acute appendicitis is the infiltration of neutrophils within the appendiceal muscularis propria. The severity and duration of the infection directly correlate with the degree and extent of inflammation observed histologically. As acute appendicitis advances, the inflammatory process extends to involve the appendiceal fat and surrounding tissues, indicating a spreading infection.

Based on histopathological characteristics, acute appendicitis is categorized into three primary types: suppurative or phlegmonous, gangrenous, and periappendicitis.

Suppurative or Phlegmonous Appendicitis: This type is marked by neutrophils infiltrating the appendiceal mucosa, submucosa, and muscularis propria. The inflammation spans the entire appendiceal wall and can cause significant ulceration. Intramural abscesses and vascular thrombosis may also be present. Grossly, suppurative appendicitis can vary in appearance but often includes a poorly demarcated serosa, dilation of the appendix, congestion of surface blood vessels, and fibrinopurulent serosal exudate. However, an increased appendiceal diameter alone is not definitive and must be interpreted with other clinical and histopathological findings.

Gangrenous Appendicitis: This is defined by necrosis of the appendiceal wall. Untreated, it inevitably leads to perforation. Histologically, transmural inflammation with necrotic areas and extensive mucosal ulceration is observed in cases of perforation. Perforation is thus considered a complication of untreated gangrenous appendicitis. Grossly, the appendix wall appears friable and may exhibit purple, green, or black discoloration.

Periappendicitis: This type primarily involves serosal and subserosal inflammation without extending into the muscularis propria. The gross appearance of periappendicitis can range from normal serosa to congestion, often accompanied by exudative infiltration.

Histopathological findings also differ between uncomplicated and complicated appendicitis.

Uncomplicated Appendicitis: Typically shows borderline-dilated serosal vessels, indicating increased blood flow, and a dulling of the serosa. Intraluminal neutrophils are common, and neutrophils may also be present in the mucosa and submucosa, with possible frank erosions. These signs point to inflammation and tissue damage.

Complicated Appendicitis:

• Complicated Appendicitis with Phlegmon: Characterized by a dilated lumen often filled with blood, indicating vascular congestion. Inflammation of the mesoappendix with exudates is noted. Neutrophils are present throughout the mucosa, submucosa, and muscularis propria, indicating a widespread inflammatory response. Extensive ulceration and intramural microabscesses may also be present, along with vascular thrombosis.

• Complicated Nonperforated Appendicitis: Includes severe phlegmonous and gangrenous non-perforated appendicitis. Severe phlegmonous appendicitis shows severe phlegmonous inflammation with obstruction and extraluminal fluid, typically due to a fecalith causing distal luminal dilation and fluid accumulation. Histology reveals pronounced transmural edema and neutrophil infiltration. Gangrenous appendicitis exhibits a friable appendix with purple, green, or black discoloration and transmural inflammation with necrosis and extensive mucosal ulceration, indicating severe inflammation and compromised blood supply.

• Complicated Perforated Appendicitis: Histopathology may show abscess formation, marked transmural inflammation, and neutrophils infiltrating tissue. Inflammation often extends beyond the appendix to the mesoappendix. This represents a severe inflammatory process with evidence of perforation, abscess formation, and high-grade inflammation.

History and Physical Examination

The hallmark symptom of acute appendicitis usually begins as a diffuse or periumbilical abdominal pain, which subsequently localizes to the right lower quadrant. This initial vague pain is due to the stimulation of visceral T8-T10 afferent nerve fibers. As the inflammation progresses and irritates the adjacent parietal peritoneum, the pain becomes more sharply defined in the right lower quadrant. Patients may describe the pain as severe enough to awaken them from sleep or worsen with movement, such as walking or coughing. Accompanying symptoms often include anorexia, nausea (with or without vomiting), diarrhea, malaise, and urinary frequency or urgency. Approximately 40% of patients with acute appendicitis present with fever at the time of examination. Atypical presentations can occur, making diagnosis challenging.

Physical examination findings can be subtle, especially in the early stages. As inflammation progresses, signs of peritoneal irritation become more evident. Localized guarding in the right lower abdominal quadrant and rebound tenderness at McBurney’s point—located about 1.5 to 2 inches from the anterior superior iliac spine (ASIS) on a straight line to the umbilicus—are commonly observed. However, these findings are not exclusive to appendicitis and can be present in other abdominal conditions.

Other physical exam signs frequently assessed in suspected appendicitis include:

• Dunphy Sign: Increased abdominal pain with coughing or any activity that raises intra-abdominal pressure.
• Rovsing Sign: Pain in the right lower quadrant elicited by palpation of the left lower quadrant.
• Psoas Sign: Right lower quadrant pain with right hip extension or right thigh flexion against resistance, indicating irritation of the psoas muscle by the inflamed appendix. Patients often flex the hip to alleviate this pain.

The symptomatic timeline in acute appendicitis varies significantly, typically escalating gradually over 12 to 24 hours from onset. However, in complicated cases, symptoms can persist beyond 48 hours. About 75% of patients seek medical attention within 24 hours of symptom onset. The risk of appendiceal rupture is approximately 2% at 36 hours from symptom onset and increases by about 5% for every additional 12 hours without intervention.

Following perforation, complications such as pylephlebitis, pylethrombosis, hydroureteronephrosis, bowel obstruction, and internal fistulae can occur. These fistulae may involve structures like the bladder, vagina, uterus, or skin, potentially leading to persistent fever and significant weight loss.

Evaluation

Laboratory Testing

Laboratory evaluation for suspected acute appendicitis should include a complete leukocyte count with differential and serum C-reactive protein (CRP) levels. The combination of white blood cell (WBC) count and CRP level enhances the positive predictive value in distinguishing between uncomplicated and complicated appendicitis. A normal WBC count and CRP value together provide a high negative predictive value for acute appendicitis. Elevated CRP and WBC levels significantly increase the likelihood of complicated appendicitis.

Leukocytosis is observed in approximately two-thirds of appendicitis cases, often accompanied by a left shift or bandemia. While no single lab value definitively confirms or rules out acute appendicitis, most patients will have a WBC count greater than 10,000 cells/mm³. A WBC count of ≥17,000 cells/mm³ is particularly associated with complicated acute appendicitis.

Imaging

While the diagnosis of appendicitis is primarily clinical, imaging modalities like computed tomography (CT), ultrasonography (US), and magnetic resonance imaging (MRI) can improve diagnostic accuracy. CT is generally the preferred imaging modality for adults with suspected appendicitis. Ultrasound is less sensitive and specific than CT but is valuable for populations where radiation avoidance is important, such as children and pregnant women. MRI can be useful for pregnant patients with inconclusive ultrasound findings.

Computed Tomography (CT)

Abdominopelvic CT scans with intravenous contrast offer over 95% accuracy in diagnosing acute appendicitis in adults. CT diagnostic criteria include:

• Enlarged appendix with an outer diameter >6-9 mm.
• Thickening of the appendiceal wall >2-3 mm.
• Periappendiceal fat stranding.
• Enhancement of the appendiceal wall.
• Inflamed soft tissue at the appendiceal base separating the appendix from the cecum.
• Presence of an appendicolith.

Intraluminal contrast or air due to distention is typically not seen in most appendicitis cases. Radiation exposure from abdominopelvic CT is a concern, but the average exposure is around 4 mSv, slightly above background exposure. Lower-dose CT protocols do not significantly affect clinical outcomes. CT with intravenous contrast should be limited to patients with a glomerular filtration rate (GFR) ≥ 30 ml/minute per 1.73 m².

Ultrasonography (US)

Abdominal US is widely available and often used as the initial imaging modality for acute abdominal pain, especially in children and pregnant women with suspected appendicitis. Ultrasonographic signs of appendicitis include:

• Anteroposterior appendiceal diameter >6 mm.
• Presence of an appendicolith.
• Increased echogenicity of periappendiceal fat.
• Non-compressibility of the appendix.

Limitations of US include its reduced effectiveness in obese patients due to adipose tissue thickness, which can hinder visualization. Graded compression during US may also be poorly tolerated in patients with complicated appendicitis and peritonitis.

Magnetic Resonance Imaging (MRI)

Abdominopelvic MRI is highly sensitive and specific for diagnosing acute appendicitis. However, its use is limited by higher costs and the need for specialized interpretation expertise. MRI is indicated primarily for pregnant patients where radiation exposure is less desirable and when ultrasound is inconclusive. MRI protocols typically involve T2-weighted sequences in three planes, sometimes with T2 fat-suppressed imaging. MRI findings consistent with appendicitis are similar to CT and US, including luminal distension, wall thickening, and periappendiceal fluid.

Scoring Systems: Alvarado Score

Scoring systems like the Alvarado score aid in the prompt diagnosis of acute appendicitis, utilizing clinical history, physical examination, and laboratory findings. The modified Alvarado score is widely used:

• 2 points each: Right lower quadrant tenderness, Leukocytosis.
• 1 point each: Migratory RLQ pain, Rebound tenderness in RLQ, Fever, Nausea/Vomiting, Anorexia.

Scores range from 1 to 9, with higher scores indicating a greater likelihood of appendicitis. A score of 7 or more is strongly associated with acute appendicitis.

Treatment / Management

Medical Management

Despite advancements in antibiotic therapy for acute appendicitis, surgery remains the primary treatment. A major randomized trial indicated that while antibiotics might offer comparable short-term results to appendectomy, about 25% of patients treated with antibiotics required appendectomy within a year.

Research on antibiotics as primary treatment for uncomplicated appendicitis has yielded mixed results. Some studies show comparable outcomes in the short term, while others report higher rates of adverse events like post-intervention peritonitis in antibiotic-treated groups. The CODA trial supports antibiotics as an option but emphasizes caution due to uncertainties about missed malignancies, recurrent appendicitis, and long-term efficacy.

The POSAW study confirms that surgical management remains the main effective option. Appendectomy remains the standard of care for acute uncomplicated appendicitis despite antibiotic alternatives.

Antibiotic regimens for appendicitis typically target both aerobic and anaerobic bacteria, often combining a third-generation cephalosporin (ceftriaxone or cefotaxime) or a beta-lactam/beta-lactamase inhibitor (ampicillin-sulbactam) for aerobic gram-negative coverage with metronidazole or clindamycin for anaerobic coverage. Antibiotic choices may vary based on local resistance patterns and patient-specific factors.

Surgical Management

Preoperatively, patients should be NPO and receive intravenous crystalloid fluids for hydration. Intravenous antibiotics are administered as per the surgical team’s protocol. Informed consent is obtained before surgery.

Appendectomy, particularly laparoscopic appendectomy, is the gold standard. Laparoscopic approach is favored for uncomplicated cases due to lower wound infection rates, reduced postoperative pain, and shorter hospital stays, although operative time may be slightly longer.

Preoperative antibiotics in uncomplicated appendicitis are debated; some surgeons routinely administer them, while others do not, and some studies advocate for antibiotics alone, avoiding surgery in select cases.

While laparoscopic appendectomy is generally feasible, factors like comorbidities, periappendicular abscess, and diffuse peritonitis may necessitate conversion to an open approach. Preoperative comorbidity is a significant independent factor predicting conversion. Intraoperative findings like abscess and peritonitis also increase conversion rates and postoperative complications.

For patients with a periappendiceal abscess, percutaneous drainage by interventional radiology may be performed to reduce inflammation before a delayed laparoscopic appendectomy. Broad-spectrum antibiotics are administered and may continue for several weeks pre-operatively. Laparoscopic appendectomy in the presence of an abscess requires extensive irrigation, and trocar sites may be left open for secondary healing.

Alternative Surgical Techniques

While laparoscopic appendectomy is preferred, open appendectomy remains relevant, especially for complicated cases with phlegmon. Newer techniques include Natural Orifice Transluminal Endoscopic Surgery (NOTES) and Single-incision Laparoscopic Surgery (SILS).

NOTES uses natural orifices for peritoneal access, aiming for scarless surgery and reduced postoperative pain. However, it’s still under development with limited patient data, and often requires hybrid laparoscopic assistance for retraction and entry site closure confirmation.

SILS involves a single incision, typically in the umbilicus, potentially reducing pain, wound complications, and recovery time. However, conversion to conventional laparoscopy is needed in up to 40% of cases, and SILS carries a higher risk of long-term incisional hernia.

Differential Diagnosis

The Appendix Differential Diagnosis for acute appendicitis is broad, encompassing several conditions that present with similar abdominal symptoms. It is crucial to consider and differentiate appendicitis from:

• Crohn Ileitis: Inflammation of the ileum due to Crohn’s disease. Differentiating features include a history of Crohn’s, chronic symptoms, and extra-intestinal manifestations. Acute presentations can mimic appendicitis, but intraoperative findings may reveal ileal inflammation.
• Mesenteric Adenitis: Inflammation of mesenteric lymph nodes, often associated with viral infections. Typically presents with diffuse abdominal pain, often preceded by upper respiratory symptoms or gastroenteritis. Physical exam findings are less localized compared to appendicitis.
• Complicated Cecal Diverticulum: Inflammation or perforation of a diverticulum in the cecum. More common in older adults. Imaging, particularly CT, is helpful in differentiation.
• Mittelschmerz: Ovulation pain, occurring mid-menstrual cycle in women. Pain is typically lower abdominal, lateralizing to either side, and correlates with ovulation timing.
• Salpingitis: Inflammation of the fallopian tubes, usually due to pelvic inflammatory disease (PID). Presents with lower abdominal pain, often bilateral, and pelvic exam reveals cervical motion tenderness.
• Ruptured Ovarian Cyst: Can cause sudden onset lower abdominal pain. Ultrasound is useful to visualize ovarian cysts.
• Ectopic Pregnancy: Should be considered in women of childbearing age with lower abdominal pain and potential vaginal bleeding. Pregnancy test is essential.
• Tubo-ovarian Abscess: A complication of PID, presenting with severe pelvic pain, fever, and often a palpable pelvic mass.
• Musculoskeletal Disorders: Abdominal wall pain can mimic appendicitis. Palpation usually elicits pain that is superficial and does not worsen with maneuvers that increase intra-abdominal pressure.
• Endometriosis: Can cause cyclic abdominal pain, often worsening with menstruation. History and gynecological exam are important.
• Pelvic Inflammatory Disease (PID): As mentioned above, PID can mimic appendicitis in women. Cervical motion tenderness is a key differentiating sign.
• Gastroenteritis: Typically presents with diffuse abdominal pain, nausea, vomiting, and diarrhea. Pain is less localized than in appendicitis, and bowel sounds are usually hyperactive.
• Right-sided Colitis: Inflammation of the colon, potentially mimicking appendicitis if localized to the right colon. Colonoscopy or flexible sigmoidoscopy may be required for definitive diagnosis.
• Renal Colic: Pain from kidney stones, often presenting with severe flank pain radiating to the groin. Hematuria is common.
• Kidney Stones: Similar to renal colic, presenting with flank pain. Urinalysis and imaging (CT or ultrasound) can confirm.
• Irritable Bowel Disease (IBS): Chronic condition with abdominal pain, bloating, and altered bowel habits. Symptoms are typically chronic and do not present as acute appendicitis.
• Testicular Torsion: In males, testicular torsion can cause abdominal pain radiating to the groin. Testicular exam is crucial.
• Ovarian Torsion: In females, ovarian torsion can present with acute lower abdominal pain. Pelvic ultrasound is diagnostic.
• Round Ligament Syndrome: Pregnancy-related pain in the lower abdomen, usually sharp and intermittent.
• Epididymitis: Inflammation of the epididymis, presenting with testicular pain that can radiate to the abdomen. Testicular exam is key.

A thorough medical history and problem-oriented physical examination are crucial to effectively narrow down the appendix differential diagnosis. Recent viral infection suggests mesenteric adenitis. Acute bacterial ileitis may be due to Yersinia or Campylobacter infections. Severe cervical motion tenderness suggests PID.

Distinguishing acute appendicitis from acute Crohn’s disease can be particularly challenging. While a known history of Crohn’s disease can guide diagnosis, Crohn’s can initially present acutely, mimicking appendicitis. Intraoperative findings of ileal inflammation should raise suspicion for Crohn’s disease.

Surgical Oncology

Appendiceal neoplasms are rare, with an incidence of about 1.2 per 100,000 in the US; approximately 30% present with acute abdominal pain. Common appendiceal malignancies include gastroenteropancreatic neuroendocrine tumors (GEP-NETs), goblet cell carcinoma (GCC), colonic-type adenocarcinoma, and mucinous neoplasm.

Gastroenteropancreatic Neuroendocrine Tumors (GEP-NETs)

GEP-NETs are the most frequent type of appendiceal malignancy. Metastasis is rare, but if it occurs, common sites are liver and lymph nodes. Evaluation of the liver and ileocolic lymph node basin is essential in suspected cases. Surgical management depends on tumor size. Appendectomy with negative margins is sufficient for carcinoid tumors ≤2 cm. For 1-2 cm tumors, management is less defined, but right hemicolectomy is advised for mesenteric invasion, enlarged lymph nodes, or uncertain margins.

Goblet Cell Carcinoma (GCC)

GCCs exhibit features of both adenocarcinoma and neuroendocrine tumors. Peritoneal evaluation and peritoneal cancer index score (PCIS) documentation are important. Right hemicolectomy is beneficial for non-metastatic lesions or tumors ≥2 cm.

Lymphoma

Non-Hodgkin lymphoma (NHL), including MALT lymphoma, can present as acute appendicitis. Surgical management is typically simple appendectomy, but systemic evaluation is needed to rule out metastasis.

Appendiceal Adenocarcinoma

Adenocarcinoma of the appendix, with three subtypes, often presents as acute appendicitis. Standard treatment is right hemicolectomy, irrespective of tumor size or lymph node involvement.

Mucocele and Mucinous Neoplasm

Appendiceal mucoceles can mimic appendicitis. They arise from benign or malignant processes involving mucosal hyperplasia and cystic formations. Preoperative imaging may suggest mucocele with a well-encapsulated cystic structure in the right lower quadrant, but definitive diagnosis is intraoperative and histopathological.

Appendectomy is the preferred surgical approach for mucoceles, with caution to avoid rupture. Peritoneal involvement should be assessed, and biopsies considered. In suspected mucinous neoplasms, thorough peritoneal examination and PCIS recording are crucial if mucin is present. Laparoscopic approach for mucocele is limited to cases with radiologically homogenous cysts.

Prognosis

Appendectomy is generally a safe procedure. Global mortality rates for appendicitis are low, around 0.28% in a global study. Mortality is higher in under-industrialized countries (1-4%) compared to industrialized nations (0.24%). Factors increasing mortality risk include age >80 years, immunosuppression, severe cardiovascular disease or comorbidities, prior suspected appendicitis episodes, and prior antimicrobial therapy.

Early diagnosis and treatment of acute appendicitis usually result in recovery within 24-48 hours. However, patients with advanced abscesses, peritonitis, or sepsis may have prolonged and complicated recoveries, possibly requiring further surgery.

Complications

The most common complication post-appendectomy is surgical site infection, particularly in complicated appendicitis with perforation. Infections include postoperative abscesses and wound infections. Hematomas and postoperative pain are also common.

Recurrent appendicitis can occur in up to half of nonoperatively managed patients. Interval appendectomy may reduce this risk. Stump appendicitis, inflammation of residual appendiceal stump due to incomplete appendectomy, can occur, especially after complicated appendicitis or if a long stump is left. Stump size ≤5 mm minimizes this risk. Stump resection is the definitive treatment, and perforated stumps may need bowel resection.

Diffuse peritonitis and sepsis are severe complications of untreated or complicated appendicitis, leading to significant morbidity and potential mortality.

Postoperative and Rehabilitation Care

Patients with uncomplicated appendicitis usually recover uneventfully and do not require postoperative antibiotics. Complicated appendicitis patients should receive a 4-day course of antibiotics. Wound complications, like infections, are managed with wound opening, irrigation, and packing. Antibiotics are essential for abscesses or deep fascial plane involvement.

Deterrence and Patient Education

Patients can typically resume normal activities within a few days to a week but should avoid strenuous activity and heavy lifting for 4-6 weeks.

Pearls and Other Issues

Patients with perforated appendicitis and abscesses without peritonitis may benefit from CT or ultrasound-guided percutaneous drainage and antibiotics, followed by interval appendectomy 6-10 weeks later. Recurrent appendicitis rates after medical management of abscesses are lower than historically reported.

Complications of appendicitis and appendectomy include surgical site infections, prolonged ileus, enterocutaneous fistula, and small bowel obstruction. Intraabdominal abscesses can occur in 3-24% of cases post-appendectomy, more often after laparoscopic procedures.

Misdiagnosis of acute appendicitis may occur when the actual diagnosis is Crohn’s disease of the cecum or terminal ileum. If the appendiceal base is involved in Crohn’s, the appendix should be left in place to avoid leaks or fistulae. If the base is unaffected, appendectomy is recommended even if the appendix appears normal to prevent future diagnostic confusion.

Historically, prophylactic appendectomy was performed during unrelated abdominal surgeries. Current practice is to leave a normal appendix in situ during scheduled procedures. However, if the preoperative diagnosis of appendicitis is incorrect, intraoperative appendectomy is advised to prevent future diagnostic dilemmas.

Enhancing Healthcare Team Outcomes

Patients with acute appendicitis typically present to the emergency department with abdominal pain. Triage teams must recognize appendicitis signs and symptoms for prompt admission and treatment to minimize perforation risk. Accurate diagnosis can be challenging.

Guidelines exist to aid diagnosis. Most clinicians rely on physical exams, while some use abdominal ultrasound. For uncertain cases, abdominopelvic CT with IV contrast is helpful; CT without contrast is an option for poor kidney function. The ACR recommends ultrasound as the primary imaging for pregnant women with suspected appendicitis, with MRI for inconclusive ultrasound results.

During investigation, intravenous access and fluids should be initiated, and patients should be NPO.

Optimal management of appendiceal mass or phlegmon and surgical timing are debated. Laparoscopic appendectomy offers less pain and faster recovery but can be costly. Single-incision approaches may be cost-effective and comparable to laparoscopy. An interprofessional team approach is essential for cost-effective and morbidity-free management.

Outcomes

Both open and laparoscopic appendectomy yield excellent outcomes for simple appendicitis. Complicated appendicitis has poorer outcomes and higher resource utilization. Atypical presentations in pregnant and elderly patients complicate diagnosis, leading to higher complication rates. Healthcare providers must adhere to current diagnostic and management standards to ensure quality care and reimbursement in managed care settings.

Review Questions

Figure

Abdomen CT, Acute Appendicitis Contributed by Scott Dulebohn, MD

Figure

Ultrasound of the right lower quadrant with findings of acute appendicitis. There is a blind ending tubular structure measuring up to 7 mm in diameter. Contributed by Kevin Carter, DO

Figure

There is acute appendicitis with a dilated fluid filled tubular structure in the right lower quadrant on this axial and sagittal images with a surrounding fluid collection and stranding due to developing abscess. Contributed by Kevin Carter, DO

Figure

Appendectomy Contributed by Sunil Munakomi, MD

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