A 40-year-old white male presented with upper abdominal (epigastric ) pain and tenderness, diarrhea, weight loss and episodes of nausea and vomiting. He was a minister, and had returned recently from 2 years of missionary work in South Africa; he stated he had been in excellent health while there but within 3 months after returning to Florida, began to develop the present symptoms. He has had the symptoms for a month. He was referred to the hospital for diagnostic tests.
Question 1 - Single Best Answer
What are some tests you might order to determine this man's illness?
A) abdominal ultrasound
B) endoscopy
C) CBC
D) stool exam
E) all of the above
Uppergastrointestinal series, abdominal ultrasound and a computerized tomogram of the abdomen were normal. An upper gastrointestinal endoscopic examination also revealed no abnormality. Initial blood tests were unremarkable except a WBC count of 9200 with 25% eosinophils. Stool cultures detected no bacterial pathogens and stool examination was negative for helminths and protozoa.
A biopsy of the small intestine was made. Histologic examination of the biopsy revealed sections of a small helminth (white arrow) and helminth larvae (black arrow) in the mucosa; extensive stool examinations showed small larvae identified as rhabditiform larvae of Strongyloides.
Question 2 - Single Best Answer
In this case of Strongyloidiasis:
A) Infection was almost certainly acquired in Africa.
B) Strongyloides infection, as hookworm, is acquired by penetration of larvae from the soil and heavy infections producing disease require repeated exposures to infected soil.
C) Strongyloidiasis is usually asymptomatic or produces only limited illness and therefore is a relatively unimportant infection.
D) The eosinophilia and symptoms in this case are typical of clinical Strongyloidiasis but are not distinctive enough to make a diagnosis.
E) In clinical cases a failure to detect infection by stool examination is unusual.
Question 3 - Single Best Answer
Strongyloides can be a serious opportunistic pathogen in contrast to most parasitic helminths. A number of biologic factors contribute to its importance as an opportunistic pathogen. What factor is probably of LEAST significance?
A) The capacity to enter a hyperinfective cycle in immuno-deficient hosts.
B) The extended longevity of infection.
C) Frequency of asymptomatic infections and difficulty in detecting infections by routine stool examinations.
D) Free living reproductive cycle in the soil.
E) Presence of animal reservoir hosts.
The potential for disseminated Strongyloides and serious even fatal disease makes it important to detect and treat Strongyloides infections in individuals that have diseases or treatments which can alter immune competence. The drug of choice for treatment of Strongyloides is Thiabendazole which is highly effective. The causes of immunodeficiency reported to facilitate a hyperinfective cycle are varied: leukemias, lymphomas, malnutrition, irradiation, systemic lupus erythromatous, several chronic infections but, surprisingly, AIDS is less associated with disseminated strongyloidiasis than would be expected. Disseminated Strongyloides infection is particularly associated with systemic treatment with corticosteroids.
Question 4 - Single Best Answer
Of the several procedures which have been used to diagnose asymptomatic or uncomplicated Strongyloides infection which is probably of LEAST value?
A) Microscopic examination of feces for Strongyloides larvae
B) Examining duodenal fluid by aspiration or string test(Enterotest)
C) Serology
D) Radiology
E) Culture
Question 5 - Single Best Answer
Which of the following are useful guidelines in the diagnosis or treatment of disseminated Strongyloidiasis?
A) If there is no eosinophilia disseminated strongyloides is very unlikely.
B) The clinical expression in disseminated infection is similar and only more intense that uncomplicated infection.
C) Detecting the parasite in disseminated infection is often difficult by the usual diagnostic methods.
D) With any sudden deterioration of an immunosuppressed patient disseminated Strongyloides should be considered.
E) In disseminated infection, disease is primarily due to septicemia by gut bacteria and antibiotic treatment is often the only specific treatment required.
