Imaging in gastric anisakiasis

Gastrointestinal Ultrasound in Infectious Diseases: A Comprehensive Review

Infectious diseases affecting the gastrointestinal tract often present diagnostic challenges due to the variability in clinical manifestations and overlapping symptoms. Ultrasound imaging has emerged as a valuable tool in the assessment of gastrointestinal pathologies, offering non-invasive and real-time visualization of anatomical structures. This review aims to explore the role of ultrasound in the diagnosis and management of infectious diseases involving the gastrointestinal tract. We discuss the imaging features of various infectious etiologies, such as bacterial, viral, and parasitic infections, highlighting characteristic findings on ultrasound scans. Additionally, we provide insights into the utility of ultrasound for the assessment of treatment response. Through a comprehensive analysis of existing literature and clinical case studies, this review underscores the significance of ultrasound imaging as a frontline modality in the diagnosis and management of infectious diseases affecting the gastrointestinal tract.

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.

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.

A case of immune checkpoint inhibitor-associated gastroenteritis detected by ultrasonography

While immune checkpoint inhibitors (ICIs) have antitumor effects, they also have characteristic side effects, including colitis. However, gastritis has rarely been reported. We report a case of a patient with lung adenocarcinoma who presented with epigastric pain and diarrhea following pembrolizumab administration. Sonography of the abdomen demonstrated diffuse, although mild, gastric wall thickening (mainly in the submucosa), as well as a slight decrease in echogenicity throughout the gastric wall. While the mucosal surface was relatively smooth, color Doppler examination showed increased vascularity. Esophagogastroduodenoscopy and pathological examination confirmed the diagnosis of ICI-related gastroenteritis.

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.

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.

Effect of freezing on the metabolic status of L3 larvae of Anisakis simplex s. s

The fish-borne parasite, Anisakis simplex s. s., triggers a disease called anisakiasis, that is associated with a gastrointestinal infection. The Anisakis is also associated with allergic response which may lead to anaphylactic shock. The A. simplex s. s. L3 larvae may be freeze tolerant despite when the nematodes will be cooled rapidly to -20 °C according to the sanitary authorities of the USA and the EU. The aim of this work was to study the metabolic status of A. simplex s. s. L3 larvae when frozen in terms of viability, expression of genes involved in the nematodes' survival of freezing, as well content of carbohydrates which play a cryoprotective role in thermal stress and are the main source of energy. The levels of trehalose were significantly higher after slow freezing treatment (p < .0001), than the fast freezing (p < .002). The lower temperatures induce changes, especially in trehalose synthesis gene expression, genes responsible for oxidative metabolism, and chaperone proteins, but we cannot state clearly whether these changes occur during freezing, or because they are already prevalent during cold acclimation. The induction of mentioned genes seems to be a common trait of both cold- and dehydration tolerance.