Keywords
gastrointestinal bleeding - HIV - strongyloidiasis
Introduction
Strongyloidiasis is a neglected parasitic disease in which the clinical presentation
is variable. Gastrointestinal (GI) bleeding as a manifestation of Strongyloides stercoralis hyperinfection in a human immunodeficiency virus (HIV) patient is rarely described
in the medical literature.
Case Report
A 59-year-old man, HIV-positive and under consistent treatment with atazanavir/ritonavir,
zidovudine, and lamivudine, presented with dark stools occurring two to three times
daily, alongside abdominal discomfort and postprandial vomiting devoid of blood traces.
Upon admission, he exhibited pallor. Cardiac and respiratory assessments showed no
abnormalities. Abdominal palpation disclosed tenderness without masses or signs of
peritoneal irritation. However, the patient subsequently developed refractory hypotension
despite volume expansion with crystalloids, necessitating vasoactive drug support.
Laboratory tests revealed anemia with a hemoglobin level of 8.2 g/dL, leukocytosis
with a white blood cell count of 11,080/μL (with neutrophils at 9,064/μL, lymphocytes
at 1,109/μL, and eosinophils at 202/μL), and a platelet count of 516,000/μL. CD4 count
greater than 350 cells/mm3 and undetectable viral load. Abdominal computed tomography (CT) revealed marked concentric
parietal thickening of the cecum and ascending colon, with contrast enhancement ([Fig. 1A]). Within the first 24 hours after clinical stabilization, he underwent upper digestive
endoscopy, which revealed a normal esophagus, atrophy of the gastric body mucosa ([Fig. 2A]), erosive gastritis with hematin in the antrum ([Fig. 2B]), and erosive bulboduodenitis ([Fig. 2C]). Stool examination for parasites and culture were requested. Due to the refractoriness
of the symptoms, 7 days later, a second abdominal CT was performed, which revealed
an increase in the extent of the concentric parietal thickening of the ascendant and
cecum, associated with densification of the adjacent fatty planes and prominent regional
lymph nodes measuring up to 1.1 cm ([Fig. 1B]). At this time of admission, histopathological examination of biopsies of the gastric
and duodenal mucosa revealed infestation with Strongyloides larvae, confirming the
diagnosis of strongyloides hyperinfection ([Fig. 2D]). Simultaneously, fecal parasitology showed the presence of Strongyloides stercoralis. It was decided to start treatment with ivermectin 200 mcg/kg/day for 14 days. He
evolved with clinical improvement and was discharged with resolution of symptoms.
Fig. 1 (A) Computed tomography (CT) of the abdomen with intravenous contrast revealing marked
concentric parietal thickening of the cecum and ascending colon. (B) Increased extent of concentric parietal thickening of the ascendant and cecum on
subsequent abdominal CT scan with intravenous contrast.
Fig. 2 (A) Upper digestive endoscopy revealed atrophy of the gastric body mucosa. (B) Erosive gastritis with hematin in the antrum. (C) In the second portion, the mucosa displays signs of swelling, enanthema, erosions,
and attenuation of the duodenal folds. (D) Gastric biopsy showed many Strongyloides stercoralis adult worms and larvae.
Discussion
Strongyloidiasis is a neglected parasitic disease, which can persist in the body chronically,
caused by Strongyloides stercoralis. This parasite is a nematode with higher prevalence in tropical and subtropical regions.
The prevalence of this infection in Brazil, an endemic country, according to community
studies, is between 11 and 20%.[1] Exacerbating the situation, there is a lack of development of specific public health
programs to control this condition.[2]
Parasitic infection occurs mainly through penetration of the skin, reaching the lung
alveoli through the bloodstream and subsequently entering the GI tract. The clinical
presentation is variable. In acute phases, dermatological manifestations may occur,
along with respiratory and GI symptoms, associated with larval migration to the small
intestine. In the chronic phase, clinical presentation can range from asymptomatic
forms to nonspecific GI symptoms, such as diarrhea and abdominal pain. In severe cases,
there may be intestinal obstruction or perforation, with hyperinfection syndrome,
especially in patients with compromised immunity.[3]
[4]
The hyperinfection syndrome, which occurred in our patient, can be defined as a change
in the immune status, in general, from the severe increase and migration of larvae,
with a consequent increase in pulmonary and GI symptoms.[3] The use of immunosuppressive medications, some viroses, like human T-lymphotropic
virus 1 and HIV, and malnutrition have been associated with serious manifestations
of this disorder.[4] HIV infection is known to cause a wide range of immune dysfunctions, affecting not
only the quantity but also the quality of the immune response. Studies reveal that
throughout the course of HIV infection, autoimmunity is induced, leading to the hyperactivation
of cellular immunity, which can generate nonspecific death of immune system cells.[5]
Changes in the innate and adaptive immune response in patients with HIV can lead to
increased susceptibility to opportunistic infections, regardless of the CD4 count,
as reported in our patient, who had, at the time of admission, a CD4 cell count within
normal limits. Studies have shown a higher prevalence of intestinal parasitic infections
in individuals with CD4 cell counts below 250 cells/μL, although other studies have
reported a higher risk of helminth infection in HIV patients with higher CD4 cell
counts.[6] This phenomenon is particularly relevant in the context of parasite infections,
such as Strongyloides stercoralis, due to its chronic nature.
The Th2 immune response, which is fundamental against helminthic infections, can be
compromised by chronic HIV infection. Infection and depletion of Th1 and Th2 cell
subsets by HIV can lead to massive decline of their responses depending on the course
of the infection.[5] This includes a possible elevated risk for developing Strongyloides hyperinfection
syndrome, a serious condition that requires immediate medical attention. A case report,
published in 2020, sheds light on the diagnostic complexities of strongyloidiasis
hyperinfection in an HIV-positive kidney transplant recipient with a stable CD4 count,
mirroring our patient's situation.[7] This underscores the imperative for heightened clinical vigilance and revaluation
of the initial screening approach for strongyloidiasis in immunocompromised individuals,
extending to those with normal CD4 counts.
GI bleeding, as seen in our patient, represents a clinical challenge. This problem
is associated with high costs and can have substantial adverse impacts on patient
health.[8] Therefore, early recognition of this symptom is essential to ensure more effective
management and treatment. When confronting GI bleeding, a broad consideration of potential
causes is essential. Peptic ulcers, often induced by Helicobacter pylori infection or nonsteroidal anti-inflammatory drug use, require prompt attention to
prevent severe hemorrhage. Portal hypertension, commonly from cirrhosis, can lead
to variceal bleeding, necessitating urgent intervention. Malignancies such as gastric
or colorectal cancer may manifest with bleeding, highlighting the importance of thorough
evaluation.[9] Inflammatory causes, such as inflammatory bowel disease, also deserve attention,
considering the misdiagnosis that can occur in cases of colitis.[10] Each etiology underscores the need for tailored management strategies to optimize
patient outcomes.
As it is a possible emergency condition, it is extremely important to conduct early
diagnosis and treatment. For the treatment of strongyloidiasis, including in asymptomatic
cases, ivermectin is the first-line medication. Studies have demonstrated the superior
efficacy of ivermectin with a lower incidence of side effects.[11] In HIV patients standard doses are typically effective at 200 mg/kg/day, for 2 days.
However, especially in immunocompromised individuals, a longer treatment duration
may be necessary. In our case, given the hyperinfection, a dosage of 200 mg/kg/day
was administered until negative stool tests were achieved over a period of 2 weeks,
although treatment duration can be personalized.[3] Furthermore, it is imperative to develop government policies to control the spread
of this disease and implement screenings for asymptomatic patients, since strongyloidiasis
remains a significant public health problem.
In conclusion, it is essential to consider intestinal parasites, particularly Strongyloides stercoralis hyperinfection, in the differential diagnosis of GI bleeding in immunosuppressed
patients. In this context, early diagnosis and timely treatment are essential to prevent
serious adverse outcomes.
