CT findings of gastric and intestinal anisakiasis. ACTA ACUST UNITED AC. 2014;39:257-261. [PMID: 24441579 PMCID: PMC3953542 DOI: 10.1007/s00261-014-0075-3]

Clinical and radiological features of gastric and small intestinal anisakiasis: comparison with gastric ulcers and crohn's disease

PURPOSE

To compare the clinical and radiological features of gastric and small intestinal anisakiasis with those of gastric ulcers and Crohn's disease.

MATERIALS AND METHODS

In this retrospective cohort study, 205 cases of anisakiasis (148 gastric; 53 small intestinal) were identified between July 2003 and February 2022. The control groups included 130 and 31 patients with gastric ulcers and Crohn's disease, respectively. Clinical and imaging findings were compared between the groups using the chi-square test, Fisher's exact test, Mann-Whitney U test, and t-test.

RESULTS

Patients with gastric anisakiasis were younger (median age, 40 [21-85] years; 87 men) than those with gastric ulcers (median age, 64.5 [29-90] years; 101 men). Abdominal pain was common in the gastric anisakiasis group, whereas bleeding symptoms were frequent in the gastric ulcer group. Patients with small intestinal anisakiasis were older (mean age, 51.2 [38.6-63.7] years; 44 men) than those with Crohn's disease (mean age, 35.9 [21.6-50.3] years; 22 men). Patients with gastric anisakiasis exhibited more edematous wall thickening, increased surrounding fat density, ascites, and thickening of other intestinal walls than those with gastric ulcers. Patients with small intestinal anisakiasis showed greater wall edema, perienteric fat stranding, proximal dilatation, clamp sign, and ascites than those with Crohn's disease. Interobserver agreement was moderate to excellent, except for esophageal findings.

CONCLUSION

Anisakiasis demonstrates clinical and radiological features distinct from those of gastric ulcers and Crohn's disease. Recognizing these differences may aid in the differential diagnosis of gastrointestinal disorders, particularly in regions with high levels of raw fish consumption. This retrospective study compared CT findings of gastric and small intestinal anisakiasis with gastric ulcers and Crohn's disease. Anisakiasis exhibited distinct features, including edematous wall thickening, increased surrounding fat density, and ascites. These findings can aid in differential diagnosis, particularly in regions where raw fish consumption is common.

First Case of Human Anisakiosis in Greece: Acute Invasive Infection Mimicking Peritoneal Malignancy

Consumption of raw and mildly processed seafood, in the context of modern Western world eating trends, is recognized as a major driver for human fish-borne infections. However, these zoonoses and their unfamiliar risks remain neglected and underappreciated among European diagnosticians. In contemporary Europe anisakidosis is one of the most important fish-borne zoonoses. It is caused by ingesting the third-stage infective larvae of the nematode parasites that belong to the family Anisakidae. The case described herein, is an intestinal and ectopic form of anisakiosis (Anisakis spp.), causing symptoms of subacute abdomen and masquerading as an intraperitoneal malignancy. It is the first anisakidosis case reported in Greece, affecting a young patient who had been repeatedly exposed to the parasite by consuming homemade raw fish. Right hemicolectomy, omentectomy and excision of a descending colon nodule were uneventfully performed. The pathology report confirmed granulomatous tissue with eosinophilic infiltration and parasites that were morphologically and molecularly identified as Anisakis spp. Although challenging, acquiring an accurate diagnosis of anisakidosis can prevent unnecessary surgery, as the infection typically is self-resolving, and if treatment is deemed necessary, it can be limited to antiparasitic medication. However, in rare cases, extra-gastrointestinal migration of larvae can cause severe damage with practically unknown risks, posing a diagnostic and therapeutic dilemma. In such a clinical case scenario, surgical exploration can decisively contribute to a definitive diagnosis and early identification of intraabdominal complications necessitating surgical intervention.

Evaluation of imaging findings in gastrointestinal anisakiasis in emergency CT and ultrasound

BACKGROUND

To assess the frequency of appearance of various signs (isolated and grouped) in emergency imaging tests in patients with anisakiasis, according to the location of gastrointestinal tract involvement.

METHODS

Retrospective review by two experienced radiologists of emergency ultrasounds and CTs performed on patients admitted in the Emergency Department of our hospital with later confirmed anisakiasis (2010-2021), assessing the presence of signs suggesting anisakiasis. Calculation of the frequency of appearance according to the gastric or intestinal location, as well as the most common grouped signs.

RESULTS

Out of 231 total patients with anisakiasis, imaging studies were performed in 144: abdominopelvic ultrasound in 43 cases and CT in 111 (both techniques in 31). In cases with gastric occurrence (34), in CT the wall stratification (100%), wall thickening (97%), fat stranding (91%) and ascitic fluid (82%) were predominant. In the intestinal cases (105), in CT (95) the wall thickening (100%), fat stranding (92%) and mesenteric vessel engorgement (83%) were usual; in ultrasound (40), ascitic fluid and wall thickening (70% in both cases) were frequently observed. The frequency of grouped appearance of the mentioned signs was 82% in gastric cases, 80% in intestinal cases and 50% in ultrasounds. Multisegment involvement in CT reached 28% (gastric + intestinal) and 11% (only intestinal) of cases.

CONCLUSIONS

The most frequent CT findings in patients with gastric anisakiasis are wall stratification and thickening, fat stranding and ascitic fluid. In the intestinal cases, wall thickening, fat oedema and vessel engorgement are the most often observed findings.

CRITICAL RELEVANCE STATEMENT

The presence of different radiological signs makes it advisable to include anisakiasis in the differential diagnosis of acute abdomen. Intestinal and multifocal involvement rates are greater than previously reported.

KEY POINTS

• In gastric anisakiasis, CT frequently shows wall stratification and thickening, fat stranding and ascitic fluid. • In intestinal anisakiasis, CT often presents wall thickening, fat stranding and vessel engorgement. • In intestinal anisakiasis, ultrasounds most frequently show ascitic fluid and wall thickening.

Intestinal anisakiasis: CT imaging findings-a 10-year descriptive study in a single center

PURPOSE

The aim of this study was to retrospectively review cases of intestinal anisakiasis diagnosed by CT over a 10-year period and to evaluate imaging findings associated with the disease.

METHODS

This retrospective study included 71 patients with clinical suspicion of intestinal anisakiasis in whom an abdominopelvic computed tomography (CT) was performed at a single institution between June 2011 and December 2021. To identify the cases, we used medical term search engines and the hospital's radiology case database. Clinical information was gathered from the medical records. A radiologist with five years of experience reviewed and analyzed the CT images to determine the characteristic findings of intestinal anisakiasis.

RESULTS

The study included 47 confirmed cases of intestinal anisakiasis. The mean age of the patients was 52 years (range 18-87 years), being more frequent in men than women (26:21). All patients reported ingestion of raw fish, most commonly anchovies in vinegar (30/47, 63,8%). Abdominal pain was the predominant symptom, accompanied by nausea, vomiting, and occasionally fever. The most common clinical suspicions were intestinal obstruction (14/47, 29,8%) and appendicitis (10/47, 21,3%), whereas intestinal anisakiasis was suspected in only 2 cases prior to imaging. CT showed thickening of the bowel wall with submucosal edema in all patients, predominantly involving the ileum (43/47, 91,5%), usually in a relatively long segment (mean of 17,5 cm, range 10-30 cm). Simultaneous involvement of multiple bowel segments was observed in 16 cases (34%). Intestinal obstruction with dilatation of proximal loops (33/47, 70,2%), ascites (45/47, 95,7%), and mesenteric fat striation (32/47, 68,1%) were also common findings.

CONCLUSION

This study demonstrates the value of computed tomography in suggesting the diagnosis of intestinal anisakiasis, which often presents with nonspecific clinical manifestations. The characteristic CT findings that provide diagnostic clues are bowel wall thickening with submucosal edema, typically involving a long segment of the ileum, with signs of intestinal obstruction, ascites, and mesenteric fat striation. Simultaneous involvement of several intestinal segments (typically the gastric antrum and right colon) is an additional finding to be considered and may provide a diagnostic clue.

Intestinal Obstruction for Anisakiasis: Surgical and Physical Therapy Treatment

Anisakiasis, a zoonotic disease that can lead to small intestine obstruction, has seen a significant rise in Spain. The country has become the first in Europe with an annual incidence of 8000 cases, primarily due to the popularity of consuming exotic dishes of undercooked or raw fish and the impact of climate change. The clinical presentation of anisakiasis can mimic symptoms of acute appendicitis or intestinal obstruction, leading to potential misdiagnosis. This case report describes a 37-year-old patient with no significant medical history who presented abdominal distension and intense pain in the right lower quadrant. The patient underwent surgery and received physiotherapy treatment, including therapeutic exercises and pulsed-pressure myofascial vacuum therapy, to facilitate functional recovery. The increasing incidence of anisakiasis in Spain underscores the need to consider it in the differential diagnosis of digestive diseases, given the high consumption of poorly prepared or raw fish in the region.

Gastric Anisakiasis Masquerading as Gastroesophageal Reflux Disease

Anisakiasis of the gastrointestinal tract is caused by the consumption of raw or undercooked seafood infected with Anisakis larvae. Penetration of Anisakis larvae into the gastrointestinal mucosa leads to severe epigastric pain, nausea, and vomiting, usually within hours of ingestion of the parasite. Suspicion for gastrointestinal Anisakiasis should be raised in patients with a compatible dietary history. Definitive diagnosis can be made by direct visualization of larvae via endoscopic examination. Although symptoms are self-limiting, the removal of larvae by gastroscopy can hasten relief of symptoms. There are a large number of cases of gastric anisakiasis reported from Japan, Korea, and Western Europe, where it is customary to consume raw fish. Cases reported from the United States are less common, and given the nonspecific symptoms of anisakiasis, the diagnosis can be missed. We report a patient who presented with gastroesophageal reflux disease like symptoms that started after ingesting raw fish. He was found by esophagogastroduodenoscopy to have white, filiform worms penetrating into the wall of his stomach, consistent with a diagnosis of gastric anisakiasis.

Anisakiasis: Imaging findings

OBJECTIVE

To review the main findings for anisakiasis in the different imaging tests that can be used to diagnose it, based on studies done at our center.

CONCLUSION

The presence of Anisakis species in food consumed in Western countries is becoming more common. Patients with anisakiasis present with acute abdomen; there are no specific clinical signs or laboratory findings. Careful history taking is key to discovering exposure to Anisakis-contaminated food, but this task is hindered by unfamiliarity with the condition and lack of suspicion and is also confounded by the variable latency period after ingestion of Anisakis-contaminated food. Give the nonspecific presentation, patients with anisakiasis often undergo imaging tests to rule out other processes. Thus, radiologists need to be familiar with the spectrum of imaging findings that should lead to the inclusion of anisakiasis in the differential diagnosis, so they can guide clinicians toward directed history taking and specific tests.

Anisakiasis of the Terminal Ileum Removed by Colonoscopy

A 35-year-old Japanese man with no significant medical history presented to the emergency department complaining of abdominal pain, nausea, and vomiting 35 h after ingesting raw horse mackerel, sardines, and tuna. Computed tomography of the abdomen with intravenous contrast revealed significant thickening of the terminal ileum with mild proximal dilatation and moderate ascites. On colonoscopy, an actively moving anisakis larva was discovered in the terminal ileum. The larva was removed with endoscopic forceps. The patient's symptoms resolved quickly following the procedure.

Ultrasonography in infectious and neoplastic diseases of the bowel and peritoneum

Ultrasonography is not the most cited imaging technique for the evaluation of infectious and neoplastic diseases of the gastrointestinal tract and the peritoneum, but it is often the initial technique used in the initial workup for nonspecific clinical syndromes. Despite its limitations, ultrasonography's strengths enable it to provide meaningful diagnostic information. To discuss the most important ultrasonographic, clinical, and epidemiological findings for infectious disease, we follow a topographical approach: stomach (Anisakis), proximal small bowel (Giardia lamblia, Strongyloides stercoralis, Mycobacterium avium-intracellulare complex, and Cryptosporidium), distal small bowel (Yersinia, Salmonella, and Campylobacter), terminal ileum and cecum (tuberculosis), right colon (Entamoeba histolytica), left colon (Shigella), sigmoid colon and rectum, pancolitis (Clostridium difficile, Cytomegalovirus, and Escherichia coli), and peritoneum. To discuss the ultrasonographic and clinical findings of the most common neoplastic diseases, we follow a nosological approach: polyploid lesions as precursors of tumors, carcinomas, neuroendocrine tumors, hematological tumors, mesenchymal tumors, and metastases. We briefly discuss tumors of the peritoneum and the use of ultrasonography to guide percutaneous biopsy procedures.

Acute Anisakiasis: Pharmacological Evaluation of Various Drugs in an Animal Model

BACKGROUND

The accidental ingestion of the third larval stage of Anisakis can cause acute clinical symptoms, which are relieved via extraction of the larvae. Although this is a highly effective technique, it can only be practiced when the larvae are found in accessible areas of the gastrointestinal tract, and therefore instead the condition has often been treated using various different drugs.

AIMS

This study evaluates the effectiveness of gastric acid secretion inhibitors (omeprazole and ranitidine), gastric mucosal protectants (sucralfate) and anthelmintics (mebendazole and flubendazole) in treating anisakiasis in Wistar rats.

METHODS

Rats were infected with Anisakis-type I larvae and administered the drugs via a gastric probe. Data were recorded regarding the number of live and dead larvae, their location both within the animal and in its feces, and the presence of gastrointestinal lesions. Additionally, gastric pH was measured and histology performed.

RESULTS

While rats in all experimental groups exhibited lesions; those treated with ranitidine and mebendazole showed significantly fewer lesions (50% and 35% of rats exhibited lesions, respectively). Histological examination of the gastric lesions revealed infection-induced changes, but no significant differences were observed between the treated and untreated rats.

CONCLUSIONS

Mebendazole was found to be most efficacious in preventing gastrointestinal lesions, followed by ranitidine, which was the most effective antacid of those studied. Both these drugs could thus be considered as part of the conservative management of anisakiasis.

World-wide prevalence of Anisakis larvae in fish and its relationship to human allergic anisakiasis: a systematic review

The infective stage of Anisakidae nematodes responsible for allergic reactions in humans is found in a variety of edible fish and cephalopods. The identification of geographical regions that are high risk for infected seafood may help prevent allergic reactions in humans. Despite an abundance of published literature which has identified anisakid larvae in an array of edible seafood as well as scattered reports of human allergic anisakiasis, the relationship between the two has not been fully explored. Therefore, a systematic spatio-temporal study was conducted to determine the prevalence of Anisakis spp. in fish from January 2000 to August 2020 firstly to explore the relationship between fish infection and cases of allergic anisakiasis and secondly to use fish infection data to map potential allergic anisakiasis 'hot spots'. A systematic literature search for original English text articles was conducted through search engines, Web of Science, Scopus, PubMed, Science Direct and Google Scholar. Out of 3228 articles which describe anisakid infection in fish, 264 were used for data extraction. Of 904 articles describing allergic anisakiasis, 37 were used for data extraction. A qualitative summary of the extracted data was performed using equal interval method (ArcMap software) in order to compare the global distribution of Anisakis-infected fish. Of the 152-identified fish hosts, five families were most commonly infected with Anisakis spp. These included Lophiidae (86.9%), Trichiuridae (77.05%), Zeidae (70.9%), Merlucciidae (67.8%) and Gadidae (56.8%). The hot spot areas for allergic anisakiasis were North and northeast of Atlantic Ocean, southwest of USA, west of Mexico, south of Chile, east of Argentina, Norway, UK and west of Iceland (confidence 99%). The highest rate of allergic anisakiasis was in Portugal and Norway with the prevalence rate of 18.45-22.50%. Allergologists should consider allergic anisakiasis as a public health issue particularly in high-risk countries where high prevalences in fish have been demonstrated.

Intestinal anisakiasis with severe intestinal ischemia caused by extraluminal live larvae: a case report

Background

Anisakiasis is a parasitic infection caused by Anisakis worms found in raw fish. Most cases of anisakiasis occur in the stomach and rarely occur in the intestine. It is extremely rare for live larvae to break through the intestine into the mesentery and cause severe intestinal ischemia. Anisakiasis can be treated conservatively, because the larvae will die in approximately 1 week, but, sometimes, a serious condition can arise, as in this case. We report the first case of extraluminal anisakiasis in which a live Anisakis worm caused severe intestinal ischemia.

Case presentation

The patient was a 26-year-old woman who ate squid a week prior. She had abdominal pain and was admitted to our emergency department. On physical examination, abdominal guarding and rebound tenderness were present in her lower abdomen. Contrast-enhanced computed tomography showed ascites, the whirl sign, localized submucosal edema of the intestinal wall, and a dilated small bowel segment with edema. We suspected the strangulated small bowel obstruction based on the CT-scan findings. To rule out the strangulated small bowel obstruction, laparoscopic exploration was performed. Bloody ascites in the pouch of Douglas and severe inflammation in 20 cm of the ileum were observed. An Anisakis larva had perforated the intestinal wall and was found alive in the mesentery. The ileum had developed a high degree of ischemia, so the affected section was resected. Histopathological examination revealed that the Anisakis worm body was in the inflamed mesentery and caused a high degree of ischemia in the intestinal tract. The patient was discharged 9 days after surgery.

Conclusions

A living Anisakis larva punctured the mesentery of the small intestine, resulting in severe intestinal ischemia. As seen in this case, intestinal anisakiasis may cause serious symptoms, and a low threshold for performing diagnostic laparoscopy for the early diagnosis of bowel ischemia secondary to anisakiasis can be useful in determining the definite diagnosis and indications for resection.

Usefulness of Ultrasound in the Diagnosis of Intestinal Anisakiasis

OBJECTIVES

To evaluate the ultrasound (US) findings of gastrointestinal anisakiasis and the utility of US in its early diagnosis.

METHODS

We retrospectively assessed the imaging findings and clinical data of 21 patients with gastrointestinal anisakiasis. Diagnosis was confirmed by a positive antigen (n = 16), endoscopy (n = 2), or a compatible clinical presentation, physical examination, and history of raw fish consumption (n = 3). Ultrasound findings reviewed included segmental circumferential bowel wall thickening, segmental edema of the valvulae conniventes, dilated small bowel loops with hyperperistalsis or hypoperistalsis, free fluid, and color Doppler hyperemia.

RESULTS

Segmental circumferential bowel wall thickening was present in all 21 patients, whereas segmental edema of the valvulae conniventes was visualized in 13 patients, moderately dilated small-bowel loops proximal to the affected segment with increased peristalsis in 14 patients, small-to-moderate ascites in 18 patients, and color Doppler hyperemia in 7 patients. The US evaluation ruled out a surgical pathologic examination in all patients, and the diagnosis of anisakiasis was suggested by the radiologist on the basis of US findings in 12 patients.

CONCLUSIONS

Familiarity with the suggestive US presentation of intestinal anisakiasis may allow the radiologist to propose the diagnosis of this overlooked cause of abdominal pain and may also prompt an investigation of recent raw or lightly cooked seafood ingestion. Ultrasound findings of bowel wall thickening, especially segmental edema of the valvulae conniventes, hyperperistalsis, and dilatation of small-bowel loops proximal to the affected segment, ascites, and color Doppler hyperemia, along with a history of raw fish ingestion should aid the radiologist in the diagnosis of anisakiasis.

Anisakiasis and Anisakis: An underdiagnosed emerging disease and its main etiological agents

Anisakiasis or anisakiosis is a human parasitic infection caused by the third-stage larvae (L3) of nematodes of the genus Anisakis, although the term is also used in medical literature for the much less frequent (<3% of cases) infection by L3 of other genera of anisakids, particularly Pseudoterranova. These parasites have a marine lifecycle. Humans are infected by the L3 through ingesting of fish and squid, the intermediate/paratenic hosts. The live larvae generally penetrate the wall of the stomach or intestine causing, among other symptoms, intense pain or allergic symptoms. These are emerging, cosmopolite illnesses. Diagnosis and treatment is usually by endoscopy and extraction and identification of the larvae. Allergic forms are usually diagnosed by prick-test and/or allergen-specific IgE detection and treated with a suitable anti-allergy treatment. The patient is also warned against further consumption of marine fish or squid, as these may be infected with Anisakis. The most common method of prevention is thermal treatment of the entire fish or squid prior to consumption (>60 °C, >1 min or - 20 °C, >24 h). Useful measures for the control of anisakiasis would be to establish a national register of cases, to initiate educational campaigns for the general public and consciousness-raising and training campaigns for health professionals. These would be complemented by control measures for the relevant sectors of the economy: fish operators, fish farming, fishermen, fishmongers, fish industry and catering facilities. Possible genetic predisposition for allergy to Anisakis and the possible relationship between anisakiasis and cancer would also require further investigation.

Parasitic diseases as a cause of acute abdominal pain: imaging findings

Acute abdominal pain can be seen in cases with parasitic diseases delivered to emergency departments. The diagnosis of the parasitic disease can be delayed because of the similar clinical signs encountered in other frequently seen causes of acute abdomen. Nevertheless, the features detected in imaging scans can be helpful in the diagnosis. The present study aims to raise awareness about abdominal parasitosis in emergency conditions and also to underline the association between imaging findings and the life cycle of parasites with illustrative cases.

It's a wormy world: Meta-analysis reveals several decades of change in the global abundance of the parasitic nematodes Anisakis spp. and Pseudoterranova spp. in marine fishes and invertebrates

The Anthropocene has brought substantial change to ocean ecosystems, but whether this age will bring more or less marine disease is unknown. In recent years, the accelerating tempo of epizootic and zoonotic disease events has made it seem as if disease is on the rise. Is this apparent increase in disease due to increased observation and sampling effort, or to an actual rise in the abundance of parasites and pathogens? We examined the literature to track long-term change in the abundance of two parasitic nematode genera with zoonotic potential: Anisakis spp. and Pseudoterranova spp. These anisakid nematodes cause the disease anisakidosis and are transmitted to humans in undercooked and raw marine seafood. A total of 123 papers published between 1967 and 2017 met our criteria for inclusion, from which we extracted 755 host-parasite-location-year combinations. Of these, 69.7% concerned Anisakis spp. and 30.3% focused on Pseudoterranova spp. Meta-regression revealed an increase in Anisakis spp. abundance (average number of worms/fish) over a 53 year period from 1962 to 2015 and no significant change in Pseudoterranova spp. abundance over a 37 year period from 1978 to 2015. Standardizing changes to the period of 1978-2015, so that results are comparable between genera, we detected a significant 283-fold increase in Anisakis spp. abundance and no change in the abundance of Pseudoterranova spp. This increase in Anisakis spp. abundance may have implications for human health, marine mammal health, and fisheries profitability.

Comparison of risk factors between human intestinal and gastric Anisakiasis

BACKGROUND

Little is known in the difference of host factors between intestinal and gastric anisakiasis. The aim of this study was to investigate the associated factors of intestinal anisakiasis in patient's characteristics and the subsequent variation compared to gastric anisakiasis.

METHODS

At St. Luke's International Hospital in Tokyo, Japan, a retrospective cohort study was conducted from April 2004 to June 2017. All adult patients who were clinically diagnosed as anisakiasis based on Computed Tomography (CT) scan or endoscopy were included, and anti-Anisakis antibodies (IgG and IgA) were measured for serological validation of anisakiasis, strengthen the diagnosis. Anisakiasis was categorized as either intestinal or gastric depending on its affected site. We compared patients' demographics, social history, and physical and laboratory findings between those with intestinal and gastric anisakiasis by bivariate analyses, followed by multivariate analyses.

RESULTS

A total of 302 patients were included in this study, where the mean age (SD) was 46.5 (14.4) and 66.6% were male. Ninety-two patients (30.5%) had intestinal anisakiasis. Multivariate regression revealed that patients with intestinal anisakiasis were more 45 years old or older (odds ratio (OR) 3.45, 95% confidence interval (CI): 1.53-7.69), male (OR 2.70, 95% CI: 1.20-6.25) and regular alcohol drinker. In terms of the physical and laboratory findings, patients with intestinal anisakiasis had greater heart rate (OR 2.86, 95% CI: 1.33-6.25), higher total protein (OR 2.86, 95% CI: 1.16-6.67), and higher C-reactive protein (CRP) (OR 11.1, 95% CI: 3.03-33.3).

CONCLUSIONS

Older males who were regular alcohol drinkers were associated with intestinal anisakiasis, and often heart rate, total protein, and CRP were elevated compared to those of patients with gastric anisakiasis.

A Second Attack of Anisakis: Intestinal Anisakiasis Following Gastric Anisakiasis

A 50-year-old man presented with epigastric pain after eating raw mackerel. Abdominal computed tomography revealed submucosal edema of the gastric antrum and pelvic ileum. Gastroscopy revealed an Anisakis simplex in the gastric antrum. His epigastric pain resolved after endoscopic removal of the Anisakis; however, he developed right lower quadrant pain the following day. Abdominal computed tomography showed submucosal edema of the terminal ileum involving different ileal loops, which was not present on admission. The patient developed delayed intestinal anisakiasis. A serving of raw fish may contain more than one Anisakis. After gastric anisakiasis, a second Anisakis may cause intestinal anisakiasis.

Pathologic Features of Infectious Gastritis

This manuscript presents a review of infectious causes of gastritis aimed at the practicing anatomic pathologist. We shall highlight unique histologic findings and clinical attributes that will assist those analyzing endoscopically obtained mucosal biopsies of the stomach or resection specimens.

Gastric and enteric anisakiasis successfully treated with Gastrografin therapy: A case report

We report a case of a 59-year-old woman who was diagnosed with gastric and small intestinal anisakiasis, which was successfully treated with endoscopic extraction and Gastrografin therapy. She was admitted to our hospital with epigastric pain and vomiting one day after eating raw fish. She exhibited tenderness in the epigastrium without obvious rebound tenderness or guarding. Computed tomography (CT) demonstrated segmental edema of the intestinal wall with proximal dilatation and a small number of ascites. Because enteric anisakiasis was suspected based on the patient’s history of recent raw fish consumption and abdominal CT, we performed gastroscopy and confirmed that nine Anisakis larvae were attached to the gastric mucosa. All of the Anisakis larvae were extracted via endoscopy, and the patient was diagnosed with gastric and enteric anisakiasis. Additionally, in the hospital, we performed ileography twice using Gastrografin, which led to shortened hospital stay. Based on the clinical results of this case, we suggest that Gastrografin therapy is a safe, convenient, and useful method to extract enteric Anisakis larvae.

Increased number of eosinophils in ascites is associated with intestinal anisakidosis

The aim of this study was to evaluate the association between eosinophils in ascites and the diagnosis of intestinal anisakidosis in patients with peritoneal signs on physical examination. We reviewed retrospectively 16 patients diagnosed with intestinal anisakidosis, evaluated between 2012 and 2015. All patients had ingested raw anchovies. The analysis of ascites fluid in ten of these patients was compared with that of 15 patients with ascites and other abdominal pathology (except liver cirrhosis). All patients had an increased number of white blood cells in the ascites fluid. The eosinophil count was significantly higher in patients with intestinal anisakidosis (P < 0.01). All patients had a good outcome. Increased eosinophils in ascites fluid is strongly associated with the diagnosis of intestinal anisakidosis.

Distinguishing gastric anisakiasis from non-anisakiasis using unenhanced computed tomography

PURPOSE

This study aimed to assess the diagnostic performance of unenhanced computed tomography (CT) for distinguishing gastric anisakiasis from non-anisakiasis gastric conditions and the reproducibility of CT findings.

METHODS

Fifty-six anisakiasis and 74 non-anisakiasis cases with gastric wall thickening on urgent observation using unenhanced CT were included. Using a κ analysis, two radiologists independently assessed the reproducibility of CT findings, including "circumferential gastric wall thickening," "gastric wall thickening extending more than two segments," "bulky and low-density gastric wall thickening," "increase in peri-gastric fat density," and "ascites." An anisakiasis diagnostic score (ADS) was developed for this study and was used to quantitatively evaluate the CT findings. An anisakiasis diagnostic prediction (ADP) with an appropriate cutoff value was used to further evaluate the ADS. Two radiologists reassessed the findings in consensus to determine the sensitivity, specificity, and accuracy of the CT findings, including the ADP and ADS area under the curve (AUC).

RESULTS

Considering reproducibility, a substantial agreement (0.6 < κ < 0.8) was achieved for all findings except "circumferential gastric wall thickening" (κ = 0.499), whereas for diagnostic performance, all findings except ascites were significantly more frequent among the anisakiasis cases. "Bulky and low-density gastric wall thickening" had the highest sensitivity (98%), whereas "gastric wall thickening extending more than two segments" had the highest specificity (80%). The ADP sensitivity, specificity, and accuracy were 91%, 84%, and 87%, respectively. The AUC was 0.902 (p < 0.05).

CONCLUSIONS

Unenhanced CT findings are useful for distinguishing anisakiasis from non-anisakiasis gastric conditions with sufficient reproducibility.

Unexpected hosts: imaging parasitic diseases

Radiologists seldom encounter parasitic diseases in their daily practice in most of Europe, although the incidence of these diseases is increasing due to migration and tourism from/to endemic areas. Moreover, some parasitic diseases are still endemic in certain European regions, and immunocompromised individuals also pose a higher risk of developing these conditions. This article reviews and summarises the imaging findings of some of the most important and frequent human parasitic diseases, including information about the parasite's life cycle, pathophysiology, clinical findings, diagnosis, and treatment. We include malaria, amoebiasis, toxoplasmosis, trypanosomiasis, leishmaniasis, echinococcosis, cysticercosis, clonorchiasis, schistosomiasis, fascioliasis, ascariasis, anisakiasis, dracunculiasis, and strongyloidiasis. The aim of this review is to help radiologists when dealing with these diseases or in cases where they are suspected. Teaching Points • Incidence of parasitic diseases is increasing due to migratory movements and travelling. • Some parasitic diseases are still endemic in certain regions in Europe. • Parasitic diseases can have complex life cycles often involving different hosts. • Prompt diagnosis and treatment is essential for patient management in parasitic diseases. • Radiologists should be able to recognise and suspect the most relevant parasitic diseases.

Anisakidosis: a fortuitous mimicker of gastrointestinal malignancy

A 51-year-old woman presented with epigastric pain, vomiting and diarrhoea. Her sister was recently diagnosed with duodenal adenocarcinoma, manifesting similar symptoms. Imaging revealed thickened gastric antrum with enlarged local lymph nodes. Endoscopy illustrated 3 worms embedded in the antral wall, identified as Anisakis simplex larvae. Larvae removal and a 2-week albendazole regimen treated the symptoms. With globalisation of cultural culinary practices, physicians must be vigilant of anisakidosis. Its ability to mimic peptic ulcer disease, chronic gastritis and malignancy necessitates broader differential diagnoses and lower thresholds for endoscopy.

Intestinal Anisakiasis Treated Successfully with Prednisolone and Olopatadine Hydrochloride

The clinical characteristic of gastrointestinal anisakiasis is severe abdominal pain after eating raw fish. Intestinal anisakiasis is more uncommon than gastric anisakiasis. Most patients with intestinal anisakiasis need hospitalization because anisakiasis can cause intestinal obstruction, ileus, peritonitis or intestinal perforation. We report a case of intestinal anisakiasis. A 43-year-old woman presented with symptoms of intermittent abdominal pain 2 days after eating raw fish. Her brother had eaten the same food and had been suffering from gastric anisakiasis. Abdominal ultrasonography in this patient showed localized jejunal wall thickening with dilated lumen of proximal jejunum and ascites. According to the clinical course and examinations, she was diagnosed with intestinal anisakiasis. Administration of prednisolone 5 mg/day and olopatadine hydrochloride 10 mg/day improved her symptoms quickly without hospitalization. Prednisolone was administered for 10 days, and olopatadine hydrochloride was administered for a total of 6 weeks according to ultrasonographic findings. Six months after the treatment, the abdominal ultrasonography demonstrated normal findings. This case demonstrates that ultrasonography was quite useful for the diagnosis and surveillance of intestinal anisakiasis. Furthermore, treatment with corticosteroid and an antiallergic agent could be an option for patients with intestinal anisakiasis.

Anisakiasis mimics cancer recurrence: two cases of extragastrointestinal anisakiasis suspected to be recurrence of gynecological cancer on PET-CT and molecular biological investigation

BACKGROUND

We report two cases of anisakiasis lesions that were initially suspected to be recurrence of gynecological cancer by positron emission tomography-computed tomography (PET-CT). Both cases were extragastrointestinal anisakiasis that is very rare.

CASE PRESENTATION

The first case was a patient with endometrial cancer. At 19 months after surgery, a new low density area of 2 cm in diameter in liver segment 4 was found on follow-up CT. In PET-CT, the lesion had abnormal (18)fluoro-deoxyglucose (FDG) uptake with elevation in the delayed phase, with no other site showing FDG uptake. Partial liver resection was performed. A pathological examination revealed no evidence of malignancy, but showed necrotic granuloma with severe eosinophil infiltration and an irregular material with a lumen structure in the center. Parasitosis was suspected and consultation with the National Institute of Infectious Diseases (NIID) showed the larvae to be Anisakis simplex sensu stricto by genetic examination. The second case was a patient with low-grade endometrial stromal sarcoma (LG-ESS). At 8 months after surgery, swelling of the mediastinal lymph nodes was detected on CT and peripheral T-cell lymphoma was diagnosed by biopsy. A new peritoneal lesion with abnormal FDG uptake was detected on pre-treatment PET-CT and this lesion was increased in size on post-treatment PET-CT. Tumorectomy was performed based on suspected dissemination of LG-ESS recurrence. The findings in a pathological examination were similar to the first case and we again consulted the NIID. The larvae was identified as Anisakis pegreffi, which is a rare pathogen in humans. Having experienced these rare cases, we investigated the mechanisms of FDG uptake in parasitosis lesions by immunohistochemical staining using antibodies to glucose transporter type 1 (GLUT-1) and hexokinase type 2 (HK-2). While infiltrated eosinophils were negative, macrophages demonstrated positive for both antibodies. Therefore, mechanisms behind FDG uptake may involve macrophages, which is common among various granulomas. This is the first report to investigate parasitosis in such a way.

CONCLUSION

These cases suggest that anisakiasis is a potential differential diagnosis for a lesion with FDG uptake in PET-CT, and that it is difficult to distinguish this disease from a recurrent tumor using PET-CT alone.

Common Symptoms from an Uncommon Infection: Gastrointestinal Anisakiasis

Clinicians can be forgiven for thinking of anisakiasis as a rare condition low in the differential diagnosis of abdominal pain. Gastrointestinal anisakiasis is a zoonotic parasitic disease caused by consumption of raw or undercooked seafood infected with nematodes of the genus Anisakis. Even though the reported cases indicate that this is a rare disease, the true incidence of the disease could be potentially higher than what is reported in the literature as cases can go undiagnosed. Diagnosis and treatment of gastric anisakiasis are made by a compatible dietary history, direct visualization, and removal of the larvae via gastroscopy. Serologic testing and imaging studies are useful in the diagnosis of intestinal anisakiasis and conservative management should be considered. This disease may mimic other diseases and lead to unnecessary surgery. This emphasizes the importance of suspecting gastrointestinal anisakiasis by history taking and by other diagnostic modalities.

Phlegmonous gastritis associated with group A streptococcal toxic shock syndrome

Phlegmonous gastritis (PG) is a rare, acute, severe infectious disease of the gastric wall that is often fatal due to Streptococcus spp. A 77-year-old man with diabetes and a gastric ulcer was urgently admitted due to prolonged nausea and vomiting. Computed tomography revealed widespread diffuse thickening of the gastric wall, and PG was suspected. The patient expired less than 9 hours after admission despite intensive treatments. Later, an analysis of the blood and gastric juice revealed group A streptococcus (GAS) and virulence factors associated with toxic shock syndrome (TSS). We herein diagnosed a patient with an extremely aggressive course of PG caused by GAS TSS.