Abstract
Strongyloides stercoralis infects the duodenum and jejunum with rare involvement of the stomach. However, the clinical presentation and endoscopic findings are non-specific. There are limited data on upper gastrointestinal endoscopy findings in S. stercoralis with gastroduodenal involvement. In this case series of seven patients, we summarize such findings after diagnosis with tissue biopsy.
Introduction
Strongyloides stercoralis (S. stercoralis) is an intestinal infection that infects about 600 million people globally, with tropical and subtropical regions contributing to around 75% of cases. 1 Infections are acquired when larvae penetrate the skin and migrate to the duodenum and upper jejunum to mature. An internal auto-infection cycle allows the parasite to reside within a human for years. 2 Clinical syndromes of S. stercoralis vary widely. Chronic infection is most often asymptomatic in healthy individuals. However, in immunocompromised conditions including chronic steroid use, diabetes mellitus (DM), malnutrition, postorgan transplantation, acquired immuno-deficiency syndrome and haematological malignancy, gastrointestinal (GI) symptoms vary from abdominal pain, chronic diarrhoea, malabsorption, and weight loss to sepsis and death. 2
The majority of the cases with GI strongyloidiasis are diagnosed based on the demonstration of larvae in the stool. 2 However, as S. stercoralis colonizes in the duodenum where the larvae mature, endoscopic evaluation has been recognized as an important tool for its diagnosis. Rare cases with gastric involvement have also been described,3,4 in which data regarding endoscopic findings are limited.
Short report
All consecutive patients diagnosed at our tertiary care center in Eastern India with gastroduodenal strongyloidiasis based on histopathology from June 2020 to June 2024 were included in this retrospective study. A total of seven such patients (median age: 46 years, range: 27–69; males: 57.1%) were identified from the hospital records. Table 1 shows their baseline characteristics.
Baseline characteristics of the patients included in the present case series.
DM: diabetes mellitus; F: female; M: male.
The most common presenting symptom was vomiting, either recurrent or persistent, which was seen in five of seven patients. Other symptoms included chronic diarrhoea, abdominal pain, weight loss, and pedal oedema. Only four patients had an immuno-compromised condition, with two having DM, one receiving chemotherapy for mandibular cancer, and another receiving immuno-modulators for psoriasis. Five patients had isolated duodenal, one had isolated gastric, and one had gastroduodenal, and jejunal involvement. The endoscopic findings in patients with duodenal involvement included duodenal scalloping with erosions (Fig. 1(a)), oedematous and erythematous mucosa (Fig. 1(b)), whitish plaque-like lesions (Fig. 1(c)), and diffuse, deep ulcers with exudates (Fig. 1(d)). The endoscopic findings in patients with gastric involvement included nodular mucosa with multiple small ulcers in the antrum and diffuse, deep ulcers with exudates in the antrum (Fig. 1(e)). All but one improved after starting oral albendazole. The single patient with mandibular cancer and significant malnutrition had extensive involvement of both duodenum and jejunum, with features suggestive of intestinal obstruction resulting in perforation peritonitis. This patient underwent emergency surgery, but succumbed to postoperative sepsis.
The endoscopic findings in patients with strongyloidiasis showing (a) duodenal scalloping with erosions, (b) oedematous and erythematous mucosa duodenal mucosa with hookworm, (c) whitish plaque-like lesions, (d) diffuse erythema with ulceration and exudates involving duodenum, and (e) antrum. (f) High power view (40×) showing larval forms of Strongyloides stercoralis in the crypts of the duodenal mucosa.
Discussion
Our case series of strongyloidiasis with gastroduodenal involvement showed varied clinical and endoscopic features associated with the disease. Detecting the organism on serial and repeated stool examinations is the gold standard for diagnosing S. stercoralis. However, typically, routine stool testing is limited because parasite output in faeces is modest owing to the sporadic presence of larvae in the stool. 2 Therefore, in order to achieve a good sensitivity, it is generally necessary to test many stool samples. Eosinophilia is a common observation in strongyloidiasis, and in our study, was present in 50%, but is not specific and is typically low in those with impaired immunity. 5 Hence, endoscopy may offer an additional modality for the diagnosis of this disease.
The endoscopic findings of strongyloides infection are usually nonspecific. 6 Gastric strongyloidiasis may show thickened gastric folds, mucosal erosions, and ulcers. A systematic review of gastric strongyloidiasis reported the antrum as the commonest site of involvement.3,4 In the present series, both patients with gastric strongyloidiasis had antral lesions with sparing of the fundus and body. Thus, multiple nodules or ulcers limited to the antrum should raise a suspicion of gastric strongyloidiasis.
In the duodenum, erythematous brownish spots, ulcers, edema, and megaduodenum may be seen. 7 In cases with disseminated disease and immunocompromised patients, the endoscopic findings looks like infiltrative disease and only biopsy leads to the diagnosis. In a large series, the commonest endoscopic findings were oedematous mucosa and white villi, followed by less common findings such as erythematous mucosa, erosions, stenosis, hemorrhage, and ulceration, with overlapping findings in the majority. The authors emphasize that whitish villi, similar to intestinal lymphangiectasia, maybe a good endoscopic marker for strongyloidiasis in endemic regions. 8 Biopsy-positive patients had more severe endoscopic findings compared to biopsy-negative patients. Strongyloidiasis was diagnosed based on duodenal biopsies in six cases where the stool was not obtained because of bowel obstruction, or larvae were not found in the stool. 7 This underscores the importance of identifying lesions on endoscopic biopsy.
Our one mortality had diffuse involvement with features of obstruction and later perforation. Bacterial infection most likely results from the release of gut flora from an ulcerated, damaged gut wall, which causes septicaemia and death. 9 Early identification and treatment of strongyloidiasis is therefore important, especially in immuno-compromised patients.
Footnotes
Declaration of conflicting interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
