Sonography in patients with suspected acute appendicitis: value in establishing alternative diagnoses

Ultrasonographic Findings after Conservative Treatment of Acute Appendicitis and Open Appendicectomy

In a randomized study we investigated the effects of antibiotics as the only treatment in acute appendicitis. Forty patients were examined, 19 after antibiotic treatment (one operated due to perforation) and 21 after surgery. All patients were examined prior to randomization, after 10 days and after 30 days. Of the positive ultrasonographic (US) findings, 18 (86%) of the 21 operated patients had histologically proven acute appendicitis. At the 10th day, 9 patients had a seroma under the scar, which had disappeared a month after surgery in all patients. In the 19 patients conservatively treated with antibiotics, the appendix could be visualized in 8 symptom-free cases on the 10th day. In 5 of the 8 patients the appendix was still visualized after 1 month. Three of these 5 had recurrent appendicitis within a year. It is concluded that US can be used not only in diagnosing acute appendicitis, but also in the evaluation of treatments such as antibiotics.

Evaluation of negative appendicectomy rate in cases of suspected acute appendicitis and to study the usefulness of ultrasonography in improving the diagnostic accuracy

CONTEXT

Acute appendicitis poses a significant diagnostic challenge to the surgeon. Despite modern advances, the diagnosis of appendicitis remains essentially clinical. Ultrasonography is effective in supplementing the clinical diagnosis.

AIMS

This study aims to evaluate the negative appendicectomy rate in patients subjected to appendicectomy and to assess the usefulness of ultrasound in improving the diagnostic accuracy.

SETTINGS AND DESIGN

It is a retrospective review of prospectively collected data on 118 patients operated for suspected acute appendicitis in a single surgical unit between May 2001 and December 2002.

METHODS AND MATERIAL

The detailed history, clinical examination and preoperative investigations according to protocol were recorded on a proforma. All patients underwent an ultrasonography of whole abdomen including pelvis. Each patient with suspected acute appendicitis was subjected to surgery and appendix was submitted for histopathological examination. The negative rate of appendicectomy, sensitivity and specificity of ultrasonography and positive and negative predictive value of ultrasound were calculated.

RESULTS

The negative appendicectomy rate was 23.72%. In males it was 13.43% and in females 37.25%. Ultrasonography had a sensitivity of 63.33 % and a specificity of 82.14 %. The predictive value of a positive test was 91.93% and the predictive value of a negative test was 41.07%.

CONCLUSIONS

The clinical diagnosis of acute appendicitis when supplemented with an ultrasonography, can achieve a reasonable degree of diagnostic accuracy with resultant low negative exploration rates thereby reducing the financial burden and morbidity by avoiding unnecessary appendicectomy and keeping the cost of treatment affordable.

Comparison of US and unenhanced multi-detector row CT in patients suspected of having acute appendicitis

PURPOSE

To prospectively compare the diagnostic performance of ultrasonography (US) and unenhanced multi-detector row computed tomography (CT) in patients suspected of having acute appendicitis by using surgery or clinical follow-up as the reference standard.

MATERIALS AND METHODS

The institutional review board approved the research protocol. Written informed consent was obtained from all patients or, for those who were adolescents, from their parents. Ninety-four patients (59 female and 35 male patients) aged 16-81 years (mean, 38 years) who were suspected of having acute appendicitis underwent both US and unenhanced multi-detector row CT of the entire abdomen. The examinations were performed within 1-2 hours of each other. US and CT images were obtained and prospectively interpreted by a different radiologist from a group of abdominal radiologists or a group of residents and general radiologists. Radiologists proposed an overall diagnosis and an alternative diagnosis. Data from US and CT were compared, and the definite diagnosis was established with surgical findings (n = 40) or results of clinical follow-up (n = 54) as the reference standard. Comparisons were made for each group of radiologists and the patient's age, body mass index (BMI), and sex. Proportion comparisons were made by using the Pearson chi2 test or the Fisher exact test. Continuous variables were compared between groups with the Mann-Whitney U test.

RESULTS

Thirty patients had definite appendicitis. The sensitivity, specificity, positive and negative predictive values, and accuracy were not significantly different between US and CT or between groups of radiologists (P values ranged from .389 to >.99), regardless of the patient's BMI (P values ranged from .073 to >.99). Misclassifications were compared with the definite alternative diagnosis and were not significantly different between US and CT or between groups of radiologists (P = .061-.592), regardless of patient age (P = .875) or sex (P = .151 and >.99 for male and female patients, respectively). The frequency of inconclusive examinations, however, was significantly higher with US than with CT, regardless of radiologist experience (P = .020 and <.001, respectively).

CONCLUSION

Although the diagnostic performances of US and multi-detector row CT are comparable, more inconclusive images were obtained with US.

Ultrasonography in Patients with Suspected Acute Appendicitis

BACKGROUND

To evaluate the usefulness and limitations of graded compression ultrasonography in the diagnosis of clinically equivocal cases of suspected acute appendicitis at the setting of mid zonal military hospital of India.

METHODS

A prospective study, graded compression ultrasonography with self localization was carried out with 3.5 MHz convex, 5 MHz convex and 7.5 MHz linear transducers (Wipro GE) in 69 clinically equivocal suspected cases of acute appendicitis. With maximal compression the anteroposterior diameter of appendix was measured from outer to outer wall. The main criterion for diagnosing appendicitis was demonstration of a non compressible appendix with anteroposterior dimension of 7mm or more.

RESULT

Sonologically 36 (52%) cases were diagnosed as appendicitis. Anteroposterior outer diameter of inflamed appendices ranged from 7mm to 21mm (mean 10.5mm). 30 (83%) of 36 patients could accurately self localize the point of maximum tenderness. There were 01 false positive and 04 false negative cases. Sensitivity and specificity were 89.7% and 96.6% respectively. Positive and negative predictive values were 97.2% and 87.8% respectively. Alternative diagnoses were offered in 33 (47.8%) cases. Amongst these 33 cases, 14(42.4%) had abdominal pain of unknown origin. Gynaecologic, urologic and gastrointestinal aetiologies were established in 10(30.3%), 07(21.2%) and 02(6%) cases respectively.

CONCLUSION

Graded compression ultrasonography superadded with self localization is an accurate means of diagnosing/excluding appendicitis in clinically equivocal cases of acute appendicitis and it is of great value in establishing alternative diagnoses.

Operator-Dependent Techniques for Graded Compression Sonography to Detect the Appendix and Diagnose Acute Appendicitis

OBJECTIVE

The objective of our prospective study was to evaluate the value of various operator-dependent techniques that allow graded compression sonography to detect normal or abnormal vermiform appendix.

SUBJECTS AND METHODS

A total of 877 subjects were included in this study. This sample population consisted of two groups: 202 control subjects and 675 patients who were suspected of having acute appendicitis. If detection of the appendix failed after a sufficient number of trials using graded compression scanning, appropriate operator-dependent techniques were used to help graded compression scanning to increase the detectability of the appendix further. The detection rate for the appendix in both groups and the diagnostic accuracy for acute appendicitis were obtained.

RESULTS

The initial graded compression sonography examination depicted the appendix in 170 (84%) of 202 subjects in the control group and 601 (89%) of the 675 patients in the patient group. We then added operator-dependent techniques to graded compression sonography for the remaining patients in whom the appendix could not be detected. The additional use of the posterior manual compression technique, low-frequency convex transducer, upward graded compression technique, or left oblique lateral decubitus change of body position allowed graded compression sonography to depict the appendix in an additional 10, eight, six, and four patients in the control group, respectively, and in an additional 27, 23, 11, and seven patients in the patient group. The number of identified appendixes was increased to 198 (98%) of the 202 patients in the control group and to 669 (99%) of the 675 patients in the patient group. Graded compression sonography with operator-dependent techniques in the patient group yielded a sensitivity of 99% (319/321 patients), specificity of 99% (350/354), and an accuracy of 99% (669/675) for acute appendicitis.

CONCLUSION

The addition of various operator-dependent techniques to graded compression sonography is useful for allowing improved visualization of both normal and abnormal appendixes.

Ultrasound-based decision making in the treatment of acute appendicitis in children

BACKGROUND/PURPOSE

Imaging techniques are used widely to diagnose appendicitis. However, the negative appendectomy rate remains at about 15%. The authors assessed ultrasound-based decision making in the treatment of acute appendicitis in children.

METHODS

The authors prospectively studied 165 consecutive children (3 to 15 years old) evaluated for appendicitis. Diagnosis and treatment were based solely on ultrasound scan findings. Criterion for appendicitis was a diameter exceeding 6 mm. Severity was classified into 4 grades based on the appearance of intramural appendiceal structure. Patients with grades I or II received antibiotic therapy. Patients with grades III or IV underwent appendectomy.

RESULTS

Ultrasound scan diagnosed appendicitis in 93 children (grade I, 7; grade II, 17; grade III, 41; and grade IV, 28). All but 2 patients with grades I or II underwent antibiotic therapy without complication. All grades III or IV patients underwent appendectomy. There was no negative appendectomy among 76 appendectomies during this period. Ultrasound-based prediction of severity was correct in 67 cases (88%). Ultrasonography identified other pathology in 39.

CONCLUSIONS

Ultrasonography in children cannot only visualize all inflamed appendices but also predict severity of disease. Treatment based entirely on ultrasound scan identified patients who required surgery for severe appendicitis and permitted successful conservative treatment for mild appendicitis.

Urological symptoms of acute appendicitis in childhood and early adolescence

We present 15 cases of acute appendicitis in ten boys and five girls (age 3-15 years) with cardinal symptomatology coming from the urogenital tract, who were treated in our departments. All the patients presented with right renal colic, dysuria, frequency and urinary retention. The symptoms were attributed to an ongoing appendix inflammatory process in close proximity to the right distal ureter and urinary bladder. All the patients were successfully operated, and postoperative courses were uneventful. As the present patient group is the largest reported to date, a classification of the pathophysiology in relation to the clinical presentation is proposed.

Sonography of acute appendicitis

Graded compression sonography is an established imaging modality in the clinical setting of acute right lower quadrant pain or to diagnose acute appendicitis because of its easy assessability, noninvasiveness, real-time imaging. However, the ability to accurately diagnose appendicitis can be affected by several factors including operator dependence, deeper-located appendix, and obesity or muscularity of the patient. However, adjuvant techniques utilizing advanced equipment and accumulated operator's experience to conventional graded compression sonography will yield more frequent detection of the vermiform appendix and more accurate results of acute appendicitis on sonography. This article introduces adjuvant techniques and various know-how of real field in the detection of the vermiform appendix and diagnosis of acute appendicitis.

Graded compression sonography with adjuvant use of a posterior manual compression technique in the sonographic diagnosis of acute appendicitis

OBJECTIVE

We evaluated the usefulness of graded compression sonography with the adjuvant use of a posterior manual compression technique for detection of the vermiform appendix and the diagnosis of acute appendicitis.

SUBJECTS AND METHODS

Five hundred seventy consecutive patients referred for suspected acute appendicitis were prospectively examined by original, graded compression sonography with a 5- or a 7.5-MHz linear transducer. A posterior manual compression technique was added for 85 patients whose vermiform appendix was not identified with graded compression sonography. For consensus, another experienced radiologist or a resident observer was in attendance throughout the examination. The detection rate for the vermiform appendix and the diagnostic accuracy for acute appendicitis before and after the adjuvant use of a posterior manual compression technique were obtained, respectively, and final diagnoses were established with the official radiology reports, surgical results, and clinical follow-up.

RESULTS

Graded compression sonography enabled visualization of the vermiform appendix in 485 (85%) of 570 patients. After the adjuvant use of a posterior manual compression technique, the vermiform appendix was found in an additional 57 of 85 patients, with the number of identified vermiform appendices increasing to 542 (95%) of 570 patients. The 57 patients with an additionally found appendix included 11 patients with acute appendicitis. The sonographic diagnosis of acute appendicitis was determined in 312 of 542 patients. Acute appendicitis was proven by surgery in 311 of 332 patients. Sonography was used to establish the diagnosis in 302 of the 311 patients with proven appendicitis; there were 10 false-positive diagnoses and nine false-negative diagnoses. One false-positive diagnosis was acquired after use of the posterior manual compression technique. These results showed more improvement than those of the probabilities for acute appendicitis with single use of graded compression sonography.

CONCLUSION

Graded compression sonography with adjuvant use of a posterior manual compression technique seems to be useful for detecting the vermiform appendix and for diagnosing acute appendicitis.

The therapeutic impact of abdominal ultrasound in patients with acute abdominal symptoms

AIM

The technical performance of abdominal ultrasound in the investigation of acute abdominal pain has been thoroughly investigated but its therapeutic effects are less well understood. We aimed to determine the therapeutic effect of abdominal ultrasound in the investigation of acute abdominal pain.

MATERIAL AND METHODS

A pre- and post-intervention observational study design was used to determine the diagnostic and therapeutic effects of abdominal ultrasound for acute abdominal pain. Referring clinicians completed a pre-ultrasound questionnaire that detailed their leading diagnosis, confidence in this and intended management in 100 consecutive adult patients. Following ultrasound a second questionnaire was completed. This again detailed the leading diagnosis, confidence in this and their intended management. Clinicians quantified the management contribution of ultrasound both for the individual case in question and in their clinical experience generally.

RESULTS

The leading diagnosis was either confirmed or rejected in 72 patients and a new diagnosis provided where no prior differential diagnosis existed in 10. Diagnostic confidence increased significantly following ultrasound (mean score 6.5 pre-ultrasound vs 7.6 post-ultrasound, P < 0.001). Intended management changed following ultrasound in 22 patients; 15 intended laparotomies were halted and a further seven patients underwent surgery where this was not originally intended. Ultrasound was rated either 'very' or 'moderately' helpful in 87% of patients, with 99% of clinicians finding it either 'very' or 'moderately' helpful generally.

CONCLUSION

Abdominal ultrasound has considerable diagnostic and therapeutic effect in the setting of acute abdominal pain.

Ultrasonography of the right lower quadrant

Whereas acute appendicitis is the most common cause of right lower quadrant (RLQ) pain, numerous other conditions may cause signs and symptoms that mimic acute appendicitis. These include other appendiceal diseases, inflammatory bowel diseases, nonbowel gastrointestinal conditions, urinary diseases, and, in females, gynecologic diseases and conditions associated with pregnancy. The important role of ultrasonography in the diagnosis of not only acute appendicitis but also each of the other conditions that cause RLQ pain is described. The ultrasound criteria for the positive, negative, and indeterminate appendix ultrasound examination and the sensitivity, specificity, and positive and negative predictive values of this modality are discussed. The limitations of ultrasound in such diagnoses are also discussed, and an algorithm for the management of patients with RLQ pain is suggested.

Appendicitis at the millennium

Acute appendicitis is a common clinical problem. Accurate and prompt diagnosis is essential to minimize morbidity. While the clinical diagnosis may be straightforward in patients who present with classic signs and symptoms, atypical presentations may result in diagnostic confusion and delay in treatment. Helical computed tomography (CT) and graded compression color Doppler ultrasonography (US) are highly accurate means of establishing the diagnosis. These imaging modalities have now assumed critical roles in the treatment of patients suspected to have appendicitis. The purpose of this article is threefold: to provide an update on new information regarding the pathophysiology, clinical diagnosis, and laparoscopic treatment of acute appendicitis; to describe the state-of-the art use of CT and US in diagnosing this disease entity; and to address the role of medical imaging in this patient population.

Suspected acute appendicitis: nonenhanced helical CT in 300 consecutive patients

PURPOSE

To determine the accuracy of helical computed tomography (CT) without the oral, intravenous, or rectal administration of contrast material in confirming suspected acute appendicitis.

MATERIALS AND METHODS

Three hundred consecutive patients referred from the departments of surgery and emergency medicine were examined for suspected acute appendicitis by using thin-section nonenhanced helical CT. All transverse CT scans were obtained in a single breath hold from the upper abdomen (T12 vertebra) to the pubic symphysis with 5-mm collimation and a pitch of 1.6. All scans were obtained without oral, intravenous, or rectal contrast material. Criteria for diagnosis of acute appendicitis included an enlarged appendix (> 6 mm) and periappendiceal inflammation. CT diagnoses were recorded prospectively. Final diagnoses were established with the results of surgical or clinical follow-up or both.

RESULTS

There were 110 true-positive diagnoses, 181 true-negative diagnoses (63 of which were an alternative diagnosis correctly established prospectively), five false-negative diagnoses, and four false-positive diagnoses, which yielded a sensitivity of 96%, a specificity of 99%, and an accuracy of 97%.

CONCLUSION

Nonenhanced helical CT is a highly accurate technique for diagnosing or excluding acute appendicitis. Developing experience with the technique and understanding the subtleties of interpretation can further improve diagnostic accuracy.

Sonographic detection of normal and abnormal appendix

AIM

The aim of the study was to assess the value of sonography in detecting the normal appendix and in identifying abnormality.

METHODS

The appendiceal wall thickness (normal: <3 mm) and ultraluminal contents (abnormal: large appendicolith, non-expressible fluid) were used as the primary criteria to determine the appendiceal status in 716 appendices. In patients who underwent appendicectomy (n = 166), surgical and histopathological findings were correlated with the ultrasound (US) findings; in patients who did not have surgery the reference standard was the clinical consensus based on follow-up.

RESULTS

Thirty-four patients out of 179 with abnormal sonographic findings did not undergo appendicectomy and recovered spontaneously; in 22 of these, the US changes were confined to the appendiceal tip. A normal appendix was identified in 537 patients (45.9% of all patients without appendicitis), with histologic verification subsequently obtained in 21. In 76 normal appendices (14.2% out of all normal appendices), luminal dilatation due to non-expressible inspissated faeces resulted in appendiceal outer diameter >6 mm (range, 6.2-12 mm); a histopathologic proof of non-inflamed appendix was obtained in seven of these.

CONCLUSIONS

A normal appendix can be visualized in a high percentage of cases and it may present with an outer diameter >6 mm (the widely-accepted upper limit of normal) due to the inspissated faecal material within the lumen. A significant percentage of early appendicitis can resolve spontaneously, especially when confined to the appendiceal tip.

Appendiceal CT in 140 cases. Diagnostic criteria for acute and necrotizing appendicitis

Computed tomography (CT) was performed in 140 patients with suspected acute appendicitis. Thin collimation (5 mm), intravenous contrast enhancement, 1-second scan times, and supplementary cecal air insufflation were emphasized. CT accuracy was 98% overall (137/140), and 99% in the 124 cases with early surgery. Necrotizing appendicitis was diagnosed by CT with 86% accuracy and 90% positive predictive value.

Evaluation of ultrasonography and clinical diagnostic scoring in suspected appendicitis

BACKGROUND

Several diagnostic aids have been developed to improve diagnosis in suspected appendicitis including ultrasonography and clinical diagnostic scoring. The aim of this study was to elaborate a new scoring system and to measure its accuracy in the preoperative diagnosis of appendicitis, comparing it with the available scoring systems.

METHODS

The clinical, radiological and ultrasonographic data of 192 patients with suspected appendicitis were collected prospectively.

RESULTS

Only six of the 12 variables analysed were shown to have prognostic significance. Using Bayesian methodology, a weight was given to each criterion and two overall scores were calculated (ultrasonographic and classical scores). A cut-off point was identified to separate patients who needed surgery and those for observation. The ultrasonographic score showed an 81 per cent sensitivity and a 96 per cent specificity, compared with 60 and 73 per cent respectively for the classical score.

CONCLUSION

Ultrasonography increases the diagnostic accuracy in patients with suspected acute appendicitis.

Applications for ultrasonography in the emergency department

The primary emergency applications of diagnostic ultrasonography are now reasonably well defined. Basic characteristics of the emergency department examination, including its rapid and highly focused nature, determine both the limitations and advantages of this technique. As greater experience and more advanced technologies develop in the emergency department setting, the role of ultrasonography will likely expand into areas that are not generally practiced today. Doppler technology, especially, promises to provide the emergency department physician of the future an even more powerful tool for the rapid diagnosis of a variety of common and critical conditions.

Abdominal ultrasonography

This article focuses on ultrasonographic examinations of the abdomen and important intra-abdominal pathology. The liver and biliary tree are discussed first, followed by the use of ultrasonography in diagnosing appendicitis, ascites, and bowel obstruction. Pyloric stenosis and intussusception, important pediatric intra-abdominal problems, are also discussed.

Appendicitis

A complete understanding of the anatomy, pathophysiology, and presenting signs and symptoms of appendicitis, combined with a thorough history and physical examination, will be the most important factors in allowing the practicing emergency physician to make the correct diagnosis of acute appendicitis. For patients in which the diagnosis is less clear or for patients in high-risk groups (extremes of age, pregnant women, and immunocompromised patients) additional diagnostic testing, usually US or CT, and early surgical consultation are recommended.

Ultrasound in the differential diagnosis of appendicitis

The purpose of this study was to determine the accuracy of sonography in detecting diseases other than appendicitis in the clinical setting of suspected appendicitis. Six hundred and nine patients were evaluated using graded compression ultrasound (US). A broad spectrum of diseases was suggested in the group of patients who eventually turned out not to have appendicitis (n = 426), including gastrointestinal (154), gynaecological (32), biliary (11), urological (8), and miscellaneous (5) abnormalities. However, out of these there were three cases of incorrect sonographic diagnoses with serious sequelae. Appendicitis coincidental with another disease capable in itself of explaining the patients' symptoms was confirmed in seven out of 10 patients where sonographically suggested; in six patients out of this group only the suggested alternative condition was held responsible for the symptoms while the inflamed appendix was overlooked. US is of considerable value in establishing alternative diagnoses in patients with equivocal signs of appendicitis. However, one should always consider the possibility of co-existing appendicitis in patients where US has revealed another condition which could be held in itself responsible for the patient's symptoms.

Ultrasonography to evaluate adults for appendicitis: decision making based on meta-analysis and probabilistic reasoning

OBJECTIVES

To review ultrasonography (US) test performance and to develop recommendations for the use of US to aid in the evaluation of potential appendicitis.

METHODS

A meta-analysis was conducted using all English-language articles published since 1986 (17 studies; 3,358 patients) to ascertain sensitivity and specificity of US for diagnosing appendicitis in adults and teenagers. Calculation of the predictive value of US was performed for three groups of patients: group I--usually operated on (prevalence of appendicitis = 80%); group II--usually observed in hospital (prevalence = 40%); and group III--usually released home (prevalence 2%).

RESULTS

Overall sensitivity was 84.7% (95% CI: 81.0-87.8%), and specificity 92.1% (88.0-95.2). The accuracy and usefulness of US were related to the likelihood of appendicitis. In group I, a positive test was accurate [positive predictive value (PPV) = 97.6%], but a negative study could not rule out appendicitis [negative predictive value (NPV) = 59.5%]. The converse was true for group III patients (PPV = 19.5%, NPV = 99.7%). Test performance accuracy was balanced only for group II patients (PPV = 87.3%, NPV = 89.9%).

CONCLUSIONS

1) US should not be used to exclude appendicitis for patients who have "classic" signs/symptoms, due to the underlying high false-negative rate. 2) US is most useful for patients who have an indeterminate probability of disease after the initial evaluation--if US is positive, the patient should have an operation; otherwise, he or she should be observed. 3) US is not recommended for screening patients who have a low probability of appendicitis, due to the low prevalence of disease and high false-positive rate in this group.

Misdiagnosis of appendicitis in nonpregnant women of childbearing age

A retrospective case series was conducted at a teaching hospital with an emergency department (ED) census of 100,000 patients per year to identify the incidence of, and factors associated with, the misdiagnosis of appendicitis in nonpregnant women aged 15 to 45 years. There were 174 nonpregnant women identified with a pathologic diagnosis of appendicitis. Clinical features were then compared between patients misdiagnosed (seen in prior 10 days and given an incorrect diagnosis) and those who were initially diagnosed correctly. The results showed that 33% of the women with appendicitis were initially misdiagnosed. The most common misdiagnoses included pelvic inflammatory disease, gastroenteritis, and urinary infections. Misdiagnosed women more frequently exhibited diffuse and bilateral lower abdominal pain and tenderness, cervical motion, and right adnexal tenderness. Misdiagnosed women also had a lower incidence of right lower quadrant pain and tenderness, and peritoneal signs. In addition, misdiagnosis was associated with an increased incidence of perforation, abscess formation, and an increase in the total length of hospitalization. In conclusion, the incidence of misdiagnosis of appendicitis in women of childbearing age is high. Women who are misdiagnosed have less typical symptoms and physical findings and more frequent abnormal pelvic findings than those who are diagnosed correctly. Emergency physicians should be aware that atypical signs and symptoms are associated with misdiagnosed appendicitis in nonpregnant women of childbearing age.

The radiologic evaluation of acute abdominal pain of intestinal origin. A clinical approach

The patient with acute abdominal pain presents the attending physician with a wide and varied gamut of diagnostic possibilities. Prompt and accurate diagnosis is essential for the proper care and management of these acutely ill patients. Diagnostic radiology is often an integral part of the emergent evaluation of these patients. This article focuses on some of the key plain-film findings in the patients suffering from acute abdominal pain of intestinal causes and reviews the radiologic evaluation of several major abdominal conditions such as acute appendicitis, diverticulitis, inflammatory bowel disease, bowel ischemia, and infarction.

Visualization of enlarged mesenteric lymph nodes at US examination. Clinical significance

PURPOSE

To identify conditions associated with enlarged mesenteric lymph nodes in children with acute abdominal pain and determine the ability of US to detect associated abnormalities.

METHODS

Two hundred and fifty children with acute abdominal pain were evaluated for the presence of enlarged mesenteric lymph nodes (AP diameter > 4 mm). Additionally, a reference group of 50 asymptomatic children was also studied for the presence of enlarged mesenteric lymph nodes.

RESULTS

Enlarged mesenteric lymph nodes were noted in 35 (14%) symptomatic children and two (4%) asymptomatic children. A specific diagnosis was established in 16/35 (46%) symptomatic children with mesenteric lymphadenopathy. Acute appendicitis was the most common diagnosis. The discharge diagnosis in the remaining 19 children was abdominal pain or gastroenteritis of unknown origin. US suggested the correct diagnosis in 12/16 (75%) children in whom a definite diagnosis was established. Histopathologic examination of enlarged mesenteric lymph nodes in three patients demonstrated non-specific inflammatory changes.

CONCLUSION

Enlarged mesenteric lymph nodes in children with acute abdominal pain represents a nonspecific finding. Mesenteric lymphadenopathy is associated with a variety of medical and surgical conditions in symptomatic children and is occasionally seen in asymptomatic children. Sonography is useful in establishing a primary diagnosis in these children.

Graded compression sonography of abdominal neoplasms mimicking acute appendicitis

Over a 3-year period nine patients (mean age of 43 years) with acute abdominal pain and unsuspected abdominal neoplasms were referred for graded compression sonography to rule out appendicitis. Six of the nine patients had right lower quadrant neoplasms involving the cecum, terminal ileum, iliacus muscle, or iliac lymph nodes. However, in three patients neoplasm was noted outside the right iliac fossa involving the liver, right kidney, and upper abdominal mesentery. This study underscores the fact that in patients without sonographic evidence of acute appendicitis, a survey of the upper abdomen and right flank should routinely be performed in addition to scanning the right iliac fossa and pelvis. In patients more than 50 years of age neoplasm must also be kept in mind in the differential diagnosis of appendicitis.

Causative role of Yersinia and other enteric pathogens in the appendicular syndrome

In 2,861 consecutive patients undergoing appendicectomy for clinically suspected appendicitis an enteric pathogen was isolated from the appendix in almost 7% using an optimal combination of culture media. The pathogenic Yersinia enterocolitica serotypes 03 and 09 predominated (3.6%), followed by Campylobacter and nontyphoid Salmonella. The same pathogen was isolated from the stool in 72.5% of patients with a culture-positive appendix and in 84.1% of those positive for a pathogenic Yersinia. Conversely, no pathogenic Yersinia were isolated in 326 gynaecologic control patients, in whom a normal appendix was removed. No frank appendicitis but mesenteric adenitis and/or terminal ileitis were found in 62.3% of 138 patients with a culture positive appendix, and in 74.6% of those positive for a pathogenic Yersinia. Histologic findings available in 135 patients showed acute suppurative appendicitis in only six (4.5%) patients, and in only one of 73 (1.4%) positive for a pathogenic Yersinia. In contrast, 46.8% of a group of 345 culture-negative appendices showed acute inflammation. A positive stool culture in a patient with suspected appendicitis, if consistent with sonographic and clinical findings, should be taken as strong evidence against the presence of true appendicitis.

The role of early sonography in the management of the acute abdomen

A prospective study was set up in a busy teaching hospital to evaluate the role of a 24 h emergency ultrasonography service in patients presenting with acute abdominal pain. Seventy-five patients due for admission via the accident and emergency department with acute onset of upper or lower abdominal pain were imaged at the request of our surgical colleagues. In 14 patients (18.7%), a diagnosis was made up by sonographic examination which had not been clinically expected. Twelve of this group were female with gynaecological pathology and all 14 had their proposed emergency surgery deferred following the sonographic examination. In 26 patients (34.7%), sonography confirmed the first diagnosis suspected clinically and in nine cases (12%) confirmed the second or third differential diagnosis. Sonography made no contribution to the diagnosis in 24 patients (32%) and in two cases (2.6%) was considered misleading. The results of this study demonstrate that emergency ultrasonography is most useful in the diagnosis of female patients presenting with mid to lower abdominal pain.

Ultrasonography in patients with suspected acute appendicitis: a prospective study

The diagnostic accuracy of high-resolution real-time ultrasonography was prospectively studied in 240 patients admitted to the hospital with suspected acute appendicitis. The criteria for ultrasound diagnosis of appendicitis included a sausage-shaped, aperistaltic, hypoechoic structure when imaged along its longitudinal axis, with a target-like appearance on transverse section. The ultrasonographic findings were correlated with surgical-pathological outcome in 82 cases with proven appendicitis, with laparotomy findings in another 21 patients and with clinical follow-up in the remainder. The overall sensitivity, specificity and accuracy of ultrasonography in the diagnosis of acute appendicitis were 78%, 92% and 87%, respectively. The positive predictive value was 84% and the negative predictive value was 88%. Ultrasonography may significantly improve the diagnostic accuracy in patients with suspected acute appendicitis and should be performed in all patients in whom the clinical diagnosis is equivocal. The ultrasonographic findings must be interpreted in light of the clinical findings.

Ultrasonography in the management of possible appendicitis in childhood

One hundred thirty-four children referred to the pediatric surgical service with the diagnosis of possible acute appendicitis underwent abdominal ultrasonography within 24 hours of admission. A final diagnosis of appendicitis was made in 45, and of gynecological disease in 11 children. One child had pancreatitis, another jejunal perforation, and a third gross mesenteric lymphadenopathy. In 75 children the clinical picture completely resolved without a definitive diagnosis being made. Clinical diagnosis of gynecological disease showed two false-negatives, and three false-positives, whereas the ultrasonographic diagnosis was accurate in all patients. The sensitivity of the pediatric surgical diagnosis at the time of admission for acute appendicitis was 49% (23 false-negatives) and the specificity was 95% (three false-positives). Ultrasonographic diagnosis of appendicitis had a sensitivity of 89% (five false-negatives) and a specificity of 92% (five false-positives). There was a negative laparotomy rate of 0.7% (one patient) using both clinical evaluation and ultrasonography. These data suggest that abdominal ultrasonography in the child with possible appendicitis is an important diagnostic adjunct.