Acute appendicitis is the most common reason for emergency abdominal surgery.


Its peak incidence occurs  among persons 10-19 years of age.


He has a lifetime risk of 7-8%.

20% of patients discharged from the hospital without a proper diagnosis.

Misdiagnosis of this entity is one of the 5 most frequent successful malpractice claims against emergency department physicians.

Appendicitis is misdiagnosed in 33% of nonpregnant women of childbearing age. 


The most frequent misdiagnoses in non pregnant women are:  PID, followed by gastroenteritis and urinary tract infection. 

Appendicitis is misdiagnosed in 25-30% of children.

Misdiagnosis  rate of appendicitis is inversely related to the age of the patient. 

The most common misdiagnosis in children is gastroenteritis, followed by upper respiratory infection and lower respiratory infection.

Children with misdiagnosed appendicitis are more likely than their counterparts to have vomiting before pain onset, diarrhea, constipation, dysuria, signs and symptoms of upper respiratory infection, and lethargy or irritability.


 Clinical physical findings in children are less likely to be documented in children with a misdiagnosis include: bowel sounds; peritoneal signs; rectal findings.

For the  evaluation of  pediatric patients, MRI has a higher sensitivity than ultrasound for the diagnosis of appendicitis: sensitivity of 100% compared to ultrasound which had a sensitivity of 76%. 

The level of urinary beta hCg human chorionic gonadotropin (beta-hCG) is useful to differentiate appendicitis from ectopic pregnancy.

Anorexia and onset of pain more than 14 days after menses suggests appendicitis, while previous PID, vaginal discharge, or urinary symptoms indicates PID. 

Appendicitis in patients older than 60 years accounts for 10% of all cases.

Misdiagnosis frequency is increased in elderly patients.

When evaluating pregnant patients with suspected appendicitis, graded compression ultrasonography should be the imaging test of choice.If ultrasonography is nondiagnostic, the patient should undergo MRI of the abdomen and pelvis.

Lifetime risk of 12% for men and 25% for women.

Incidence of 86 for every 100,000 people worldwide.

Most common cause of emergent surgery in children with 60-80,000 cases per year in the U.S.

Acute appendicitis is the most common cause of acute abdomen in young adults.

Peak incidence between 10 and 30 years of age.

The use of advanced imaging and laparoscopic techniques may have increased the number of patients with the diagnosis.

Diagnostic delay with perforation in pregnancy increases fetal and maternal morbidity. 

The appendiceal lumen is occluded in the early stages of appendicitis with distension secondary to secretions.

Thought to be a result of luminal obstruction with a fecalith, distention, bacterial overgrowth and increased intraluminal pressure which compromise of tissue with resultant gangrene and perforation.

Untreated Appendicitis, when associated with rupture, can lead to abscess, peritonitis, sepsis, and death.

Management of patients with an appendiceal mass can usually be divided into the following 3 treatment categories:

Patients with a small abscess: After intravenous (IV) antibiotic therapy, an interval appendectomy can be performed 4-6 weeks later.

Patients with a larger well-defined abscess: After percutaneous drainage with IV antibiotics is performed, the patient can be discharged with the catheter in place. 

Interval appendectomy can be performed after the fistula is closed.

Patients with a multicompartmental abscesses require early surgical drainage.

Uncomplicated appendicitis has traditionally been treated with appendectomy, and accounts for approximately 80% of cases.

Recent studies however suggest only 25% of patients have increased luminal pressure and only 18% have fecaliths with appendicitis.

Necrosis and perforation is the most serious complication and they develop when arterial blood flow is compromised.

In the early stages of the disease the visceral nerves that enter the spinal cord at T8-10 are stimulated by the inflamed appendix and can cause referred pain to the epigastrium and periumbilical areas.

As the appendix distends it becomes ischemic and the luminal bacteria invade the appendix wall with transmural inflammation and local peritonitis.

Hyperplasia of the submucosal lymphoid follicles of the appendix accounts for nearly 60% of obstructions of the appendicle lumen.

In children and older adults the most common reason for obstruction of the lumen of the appendix is a fecalith, accounting for 35% of cases.

It is a difficult process to diagnose in young children as classic symptoms are present in fewer than 60% of patients.

Patients with appendicitis may not have the reported classic clinical picture 37-45% of the time.

This is especially true when the appendix is located in an unusual place.


Accessory signs are helpful for diagnosis: the obturator sign is present when the internal rotation of the thigh elicits pain with pelvic appendicitis, and the psoas sign is present when the extension of the right thigh elicits pain with retroperitoneal or retrocecal appendicitis.

In children there is a lack of migration of pain to the right lower quadrant in 50% of cases, absence of anorexia in 40%, no rebound tenderness in 52% and vomiting often precedes abdominal pain, unlike adults.

Almost 45% of children diagnosed with appendicitis present with atypical features including absence of maximal pain in the right lower quadrant, abrupt onset of pain, no migration of pain, no guarding, no rebound, no percussive tenderness, negative Rovsing sign, no anorexia, no fever and normalor increased bowel signs.

Among children with uncomplicated appendicitis, initial non-operative management with antibiotics had a success rate of 67.1% compared with urgent surgery, and is associated with fewer disability days at one year (Minneci PC).

Acute appendicitis remains diagnostically challenging and cannot be excluded on the basis of normal CRP and White blood cell count.

Serial clinical and biochemical assessment is warranted in patients with acute abdominal pain, particularly in those presenting early after symptom onset.

Pressure on the left lower quadrant with pain appearing in the right lower abdomen suggest appendicitis and is called the Rovsing’s sign.

About 15% of patients with retrocecal appendicitis do not localize signs and symptoms to the right lower quadrant but rather to the psoas muscle.

Patients with retrocecal appendicitis typically have vomiting prior to pain in their presentation.: They may have no pain until advanced appendicitis or perforation of the appendix.

Patients with the appendix deep in the pelvis may have signs and symptoms related to the rectum or bladder and present with diarrhea or dysuria.

Patients with appendicitis with a medial positioned appendix may have suprapubic pain, and patients with a laterally positioned appendix may have flank pain.

Local peritonitis causes a shift in maximal pain the right lower quadrant of the abdomen.

As the disease progresses the appendix infarcts and perforates within 24-36 hours.

Most perforations probably have occurred by the time the patients arrives at the hospital, and the rate of exploration has not been found to have any influence in the incidence of perforation.

The strategy to prevent perforations by liberal and early exploration of patients with suspected appendicitis is not supported.

Triad of anorexia, periumbilical pain that migrates to McBurney’s point, and nausea occurs in only 50% of patients with appendicitis.

Trends in modern times: a decreasing incidence, a shift in the proportion of operations in the elderly and improved diagnostic accuracy.

Migratory pain, physical examination and initial leucocytosis remain reliable and accurate in diagnosing appendicitis.

In patients with a abdominal pain in whom appendicitis was suspected and ultrasound nondiagnostic, the strongest predictors of diagnosis were migration of pain to the right lower quadrant and vomiting.

Nearly 85% patients have symptoms for less than 2 days, but some may experience pain for a week or more.

About 2% of patients have atypical presentations with abdominal pain for 2 or more weeks.

Approximately 90% of patients with appendicitis have right lower quadrant tenderness.

Laboratory tests are not specific for appendicitis.


80-85% of adults with appendicitis have a white blood cell (WBC) count greater than 10,500 cells/µL. 


Neutrophilia greater than 75% occurs in 78% of patients. 


Less than 4% of patients with appendicitis have a WBC count less than 10,500 cells/µL and neutrophilia less than 75%.


WBC counts In infants and elderly patients especially unreliable because these patients may not mount a normal response to infection. 


In pregnant women physiologic leukocytosis renders the CBC count useless for the diagnosis of appendicitis.


C-Reactive Protein an acute-phase reactant synthesized by the liver in response to infection or inflammation,  rapidly increases within the first 12 hours. 


CRP it lacks specificity and cannot be used to distinguish between sites of infection.


CRP levels of greater than 1 mg/dL are commonly reported in patients with appendicitis.


Very  high levels of CRP in patients with appendicitis indicate gangrenous complication of the disease, especially if it is associated with leukocytosis and neutrophilia. 


CRP normalization occurs 12 hours after onset of appendicitis symptoms. 


Adults who have had symptoms for longer than 24 hours, a normal CRP level has a negative predictive value of 97-100% for appendicitis.


An normal CRP level after 12 hours of symptoms is  100% predictiv  of a benign, self-limited illness. 



There is a 93-96.6% sensitivity of CRP in  patients with histologically proven appendicitis. 



Investigators have found that the WBC count or CRP level was abnormal in all 200 patients with appendicitis in their cohort of 300 patients operated for suspected appendicitis. 



A normal WBC count and CRP level had a negative predictive value of 92.3% for the presence of appendicitis in prospectively studied patients referred to a surgeon for RLQ pain. 


Among 100 children undergoing surgery for suspected appendicitis, either the WBC count or CRP level was elevated in 98% of those with pathology-proven appendicitis.


In the early stages of appendicitis, the appendix grossly appears edematous with dilation of blood vessels. 

Appendicitis demonstrates neutrophil infiltrate of the mucosal and muscularis layers.

Later, the appendiceal wall grossly  thickens, the lumen appears dilated, a serosal exudate may seen,

mucosal necrosis may be observed microscopically.

In the later stages of appendicitis, there are signs of mucosal necrosis extending into the external layers of the appendiceal wall that can become gangrenous. 


Mild pyuria may occur in patients with appendicitis because of the relationship of the appendix with the right ureter. 



One study of 500 patients with acute appendicitis revealed that approximately one third reported urinary symptoms, most commonly dysuria or right flank pain. 



One in 7 patients has pyuria greater than 10 WBCs per high power field (hpf), and 1 in 6 patients had greater than 3 red blood cells (RBCs) per hpf: diagnosis of appendicitis should not be dismissed due to the presence of urologic symptoms or abnormal urinalysis. 



Urinary 5-hydroxyindoleacetic acid levels could be an early marker of appendicitis. 



There are serotonin secreting cells in the appendix that account for increased urinary 5-hydroxyindoleacetic acid levels in acute appendicitis.



If urinary  5-hydroxyindoleacetic acid levels fall it could suggest inflammation shifted to necrosis of the appendix, and the presence of impending appendices perforation.

There is leukocytosis in 70-90% of patients, but may be within the normal range in the first 24 hours.

Increasing white count occurs as the disease progresses, and a WBC count greater than 15,000 mm cubed, suggest perforation of the bowel.

Ultrasound visualization in children has limitations with visualization of the appendix rates varying from 22-98% and sensitivities ranging from 74 to 100% and specificities ranging from 88 to 90% in the diagnosis of appendicitis.

Ultrasound imaging is limited in patients who have a high BMI as fat absorbs and diffuses the ultrasound beam.

A negative ultrasound examination in the presence of clinical findings to suggest appendicitis, is not sufficient to exclude the diagnosis.

Ultrasonography is a safer alternative as a primary diagnostic tool for appendicitis, with CT scanning used in those cases in which ultrasonograms are negative or inconclusive.

Plain radiographs are insensitive, nonspecific, and not cost-effective.

Barium enema  study has  no role in the diagnosis of acute appendicitis.

The appendix cannot be visualized in 50% of healthy individuals; therefore, barium enema lacks reliability.

Radionuclide Scanning for neutrophils and macrophages that are labeled with technetium Tc 99m (99m Tc) albumin and administered intravenously.: Localized uptake of tracer in the RLQ suggests appendiceal inflammation.

Magnetic resonance imaging (MRI) has  a relatively limited role in the evaluation of appendicitis because of its high cost, long scan times, and limited availability. 

Its lack of ionizing radiation makes it an attractive modality in pregnant patients. 

MRI may be superior to transabdominal ultrasonography in evaluating pregnant patients with suspected appendicitis. 

The sensitivity and specificity of MRI for appendicitis appears to be similar to those of computed tomography (CT) scanning.

A healthy appendix usually cannot be viewed with ultrasonography, but when appendicitis occurs, the ultrasonogram typically demonstrates a noncompressible tubular structure of 7-9 mm in diameter.


The appendiceal  tubular structure is noncompressible, lacks peristalsis, and measures greater than 6 mm in diameter. 



Ultrasonography followed by magnetic resonance imaging (MRI) appears to be an effective combination for accurately diagnosing appendicitis in children. 



Vaginal ultrasonography alone or in combination with transabdominal scan may be useful to determine the diagnosis of appendicitis in women of childbearing age. 



In patients with complicated appendicitis, including gangrenous, with or without perforation: the only significant independent predictor of complicated appendicitis was loss of the normally echogenic submucosal layer, with 100% sensitivity and 92.0% specificity. 

The overall accuracy for diagnosing acute appendicitis is approximately 80%, with mean negative appendectomy rate of 20%. 


Diagnostic accuracy varies by sex, with a range of 78-92% in males and 58-85% in female patients.



Diagnosis by history of anorexia and periumbilical pain followed by nausea, right lower quadrant (RLQ) pain, and vomiting occurs in only 50% of cases. 

CT scan of the abdomen and pelvis has a sensitivity of approximately 96% and specificity of 95% to 98%.

Abdominal CT scan indicates appendicitis when the appendiceal diameter exceeds 6 mm with wall thickening and at least one of the following: abnormal contrast enhancement of the appendiceal wall, inflammatory edema, or fluid collections around the appendix.

CT use coincides with a reduction in the rate of negative, that is unnecessary, appendectomies without an increase in the rate of appendiceal perforations.

CT scans in patients suspected of having appendicitis is cost-effective, preventing delays or inaccurate diagnoses.

In a single institution non-inferiority trial randomly assigning 891 patients with either low dose abdominal CT scanner or standard CT scan the former was noninferiot to the latter, with respect to negative appendectomy rates in young adults with suspected appendicitis (Kim K et al).

Low-dose abdominal CT allows for a 78% reduction in radiation exposure compared to traditional abdominopelvic CT and may be preferable for diagnosing children and young adults in whom exposure to CT radiation is of particular concern. 

In adults with appendicitis, the diagnostic performance of CT scans with intravenous contrast alone is comparable to that of scans with both intravenous and oral contrast.

A single typical abdominal CT examination confers a small but real risk of carcinogenesis and reducing radiation dose by 50-80% with low-dose CT techniques does not significantly hinder a diagnosis of appendicitis.

Low-dose CT is not inferior to standard dose CT with respect to negative appendectomy rates in young adults with suspected appendicitis (3.5% vs 3.2%) (Kim K et al).


Computed tomography (CT) scanning with oral contrast medium or rectal Gastrografin enema are imaging studies used to detect atypical appendicitis, including inguinal or femoral canal, subhepatic, retrocecal, intraperitoneal abdominal midline as well as left side in situs inversus or intestinal malrotation patients. 

Mortality 0-1.4%.Mortality with rupture increases to approximately 2-3%.

Mortality has fallen to about 1 in 600.

In patients with comorbid conditions, diagnostic delay is correlated with increased morbidity and mortality.

Primary adverse outcome is a ruptured appendix.

Necrosis and perforation is the most serious complication and they develop when arterial blood flow is compromised.

With ruptured appendix, at the time of exploration, there is a 39% likelihood of having a postsurgical complication which includes: abscess, ileus or wound infection.

In the absence of appendiceal rupture only 8% of patients have a postoperative complication.

Appendiceal rupture rate 30-74% among children.

Alvarado clinical scoring system is a diagnostic tool for abdominal pain and includes:

Migration of pain to the right lower quadrant with anorexia, nausea, or emesis-one point each

Right lower quadrant tenderness on exam-two points

Rebound pain or elevated temperature-one point each

Leucocytosis -two points

Left shift-1 point

In the above clinical scoring system a score of four or less is very unlikely to be associated with acute appendicitis, whereas the closer the total reaches to 10, the more likely acute appendicitis is present.

Treatment primarily surgery but in the Appendicitis ACUTA (APPAC) trial a randomized clinical trial examining the effect of antibiotics (ertapenem) for treating CT confirmed uncomplicated appendicitis instead of surgery: of the 273 patients in the surgical group 272 underwent successful appendectomy and among 256 patients in the antibiotic group 70 patients or 27.3% underwent surgical intervention with in one year of appendicitis and 72.7% did not require surgery (Salminen et al).

In the above study most patients randomized to antibiotic treatment did not require appendectomy during the one year follow-up, and those who did require appendectomy, they did not experience significant complications.

Antibiotics used in treating appendicitis must offer full aerobic and anaerobic coverage. 

Antibiotic prophylaxis is administered before every appendectomy.

In a European studies patients with appendicitis were treated with intravenous antibiotics for 24 hours followed by seven days oral antibiotics, usually ciprofloxacin and metronidazole: most avoided appendectomy with 10-37% of patients ultimately requiring an appendectomy within 4.2-7 months.

Studies comparing antibiotics with appendectomy reveal More than 70% of patients can be successfully treated with antibiotics (Vons C).

In a prospective study of patients with ultrasonography-proven appendicitis, symptoms resolved in 95% of patients receiving antibiotics alone, but 37% of these patients had recurrent appendicitis within 14 months. 

The Appendicitis Acuta (APPAC) trial compared antibiotic therapy with appendectomy in the treatment of patients with uncomplicated acute appendicitis did not demonstrate noninferiority of antimicrobial management versus surgery. 

A report of children with perforated appendicitis, found that those who underwent early appendectomy had significantly better outcomes than those who received medical management.

Preoperative broad-spectrum gram-negative and anaerobic coverage antibiotics have demonstrated efficacy in decreasing postoperative wound infection rates in prospective controlled studies; 

Broad-spectrum gram-negative and anaerobic coverage is indicated.

The risk of appendiceal rupture is minimal in patients with less than 24-36 hours of symptoms.

Appendectomy within 12-24 hours of presentation is not associated with an increase in hospital length of stay, operative time, or complications compared with appendectomy performed within 12 hours of presentation.

An evaluation by the American College of Surgeons of 30-day morbidity and mortality of intervention found similar outcomes between when appendectomy was performed within 24 hours and when it was performed between 24-48 hours. 

However, delay of operative intervention longer than 48 hours was associated with doubling of complication rates.

Patients with perforated appendicitis with mild symptoms and localized abscess or phlegmon on abdominopelvic computed tomography (CT) scans can be initially treated with IV antibiotics and percutaneous or transrectal drainage of any localized abscess. 

Delayed appendectomy can be performed 4-8 weeks later.

Studies are needed to clarify not only whether routine interval appendectomy is indicated

Laparoscopic appendectomy is successful in approximately 90% of cases of perforated appendicitis. 

Laparoscopic appendectomy is

contraindicated in patients with significant intra-abdominal adhesions.

The indications for laparoscopic appendectomy are identical to those for open appendectomy. 

Guideline lists the following conditions as suitable for laparoscopic appendectomy: 

Uncomplicated appendicitis

Appendicitis in pediatric patients

Suspected appendicitis in pregnant women

Laparoscopic appendectomy may be the preferred approach

Perforated appendicitis

Appendicitis in elderly patients

Appendicitis in obese patients

Laparoscopic approach should be preferred in women of childbearing age with presumed appendicitis. 

Diagnostic laparoscopy may be useful in cases such as infants, elderly patients, and female patients to confirm the diagnosis.

In a systematic review and meta-analysis of 11 studies on laparoscopic versus open appendicectomy for suspected appendicitis in pregnancy: laparoscopic appendectomy in pregnant women was associated with a significantly greater risk of fetal loss. 

Complications of appendectomy may include wound infection, dehiscence, bowel obstruction, abdominal/pelvic abscess, and, rarely, death. 

Stump appendicitis also occurs rarely

Antibiotics have an important role in the treatment of appendicitis, and must have  full aerobic and anaerobic coverage. 

The duration of the administration of antibiotics is  related to the stage of appendicitis at the time of the diagnosis.

Antibiotic agents decrease the rate of postoperative wound infection and in improving outcome in patients with appendiceal abscess or septicemia. 

It is recommended to  start prophylactic antibiotics before surgery, using appropriate spectrum agents for less than 24 hours for nonperforated appendicitis and for less than 5 days for perforated appendicitis. 

Non-operative treatment is associated with a shorter duration of disability than appendectomy, does not routinely require hospitalization, and is not associated with an increased risk of rupture.
Over five years, approximately 30-40% of patients treated with antibiotics will undergo appendectomy.
In a study of uncomplicated acute appendicitis treated with either seven days of oral moxifloxacin or two days of intravenous ertapenem followed by five days of Levifloxacillin and metronidazole:treatment success, discharge from the hospital without need for surgery and no recurrent episodes of appendicitis within one year occurred in70.2%, and in the oral antibiotic  group alone versus 73.8% of the patients who received intervenous followed by oral antibiotics therefore, they study showed noninferiority.(APPAC II Trial).

In a study of surgical treatment for appendicitis versus antibiotics, at 30 days antbiotics were non inferior to appendectomy.: However by 90 days follow up approximately 1/3 of the patients assigned to receive antibiotics hand  undergone an appendectomy and complication rate was twice as high as in the appendectomy group with increased emergency department visits and more time spent in the hospital(CODA Collaborative).

When chosen by the family an non-operative approach is as effective a treatment strategy for children with uncomplicated acute appendicitis associated with less morbidity and lower costs than surgery (Telem DA).

Randomized controlled studies have demonstrated that administering opioid analgesic medications to adult and pediatric patients with acute undifferentiated abdominal pain is safe; no study has shown that analgesics adversely affect the accuracy of physical examination. 

Acute appendicitis during pregnancy may be associated with maternal or fetal morbidity, and antibiotic therapy for uncomplicated simple appendicitis during pregnancy can be treated successfully in 75% of patients (Joo J).

During pregnancy acute appendicitis is the most common non-obstetric surgical emergency.

Perforated appendicitis is associated with the 6% rate of fetal loss, and 11% rate of early delivery.

For negative appendectomies, the rate of fetal loss was is 4% and the rate of early delivery is 10%.

The above findings suggest the necessity of more timely and accurate diagnosis to reduce the risk of perforation, unnecessary surgery in pregnant patients and improve perinatal outcomes.

In pregnant women with abdominal pain, ultrasound is the initial imaging test.

Ultrasound in acute appendicitis has poor specificity, with the normal appendix visualized in less than 2% of pregnant patients without appendicitis.

Appendicolith is found in proximally 25% of patients in whom appendicitis is confirmed on imaging and is associated with an increased chance of appendiceal rupture.

When diagnostic uncertainty remains after ultrasound, an MRI imaging should be entertained.

When MRI is unavailable CT scan should be utilized.

Radiation exposure through x-rays, CT scan, or nuclear medicine imaging techniques at a dose that much lower less than exposure associated with fetal jar, and should not be withheld from the pregnant patient.

Differential diagnosis: 



Pelvic inflammatory disease (PID) or tubo-ovarian abscess, 






Ovarian cyst or torsion, 



Ureterolithiasis and renal colic, 



Degenerating uterine leiomyomata,






Crohn disease



Colonic carcinoma



Rectus sheath hematoma






Bacterial enteritis



Mesenteric adenitis and ischemia



Omental torsion



Biliary colic



Renal colic



Urinary tract infection (UTI)












Perforated duodenal ulcer



Appendiceal stump appendicitis, 







Psoas abscess


Abdominal Abscess


Bacterial Gastroenteritis




Urinary Tract Infection (UTI) and Cystitis (Bladder Infection) in Females


Ectopic Pregnancy


Inflammatory Bowel Disease




Pediatric Meckel Diverticulum


Urinary Tract Infection (UTI) in Males





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