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A 71-year-old man was investigated for recent unintentional weight loss of approximately 15 kg (>20% total body mass) within the past 3 months. His past medical history included type 2 diabetes mellitus and hypertension, and he was an ex-smoker with a 40 pack-year history. Resident in the UK for 50 years, he was originally from Sierra Leone with no recent travel history.
Examination revealed cachexia and lymphadenopathy. Admission blood tests demonstrated a white cell count of 12.1×109/L (with eosinophil level raised at 1.0×109/L), microcytic anaemia (haemoglobin of 109 g/L with mean cell volume (MCV) of 68 fl), hypoalbuminaemia (albumin of 20 g/L) and raised inflammatory markers (C reactive protein of 62 mg/L). Tissue transglutaminase IgA levels were within normal limits, with no evidence of IgA deficiency.
An abdominal CT with contrast was reported as showing marked circumferential thickening of the wall of the duodenum and jejunum (in some places, up to 1 cm diameter), well beyond the degree that could be explained by the patient's hypoalbuminaemia alone (figure 1). A push enteroscopy demonstrated haemorrhagic gastritis in the antrum, as well as evidence of very abnormal-appearing, oedematous, engorged villi within the distal duodenum and proximal jejunum (figure 2).
What is the underlying diagnosis?
See page 1888 for answer
See page 1846 for question
Histology of jejunal biopsies demonstrated larvae of Strongyloides stercoralis (figure 3) while stool assays were also positive, together confirming the diagnosis of S. stercoralis hyperinfection. Despite treatment with oral ivermectin, the patient developed multiorgan failure from disseminated infection and died.
S. stercoralis is a roundworm endemic in tropical and subtropical regions including Sierra Leone, where the prevalence is estimated at more than 25%.1 Transmission is through direct penetration of skin by infected larvae while in contact with soil or other materials contaminated by human faeces; poor sanitation is therefore a major risk factor for infection. Many infected patients experience mild, intermittent symptoms and display no laboratory abnormalities aside from eosinophilia. The parasite can complete its entire life-cycle within humans, with any defect in host cell-mediated immunity substantially increasing the risk of progression to hyperinfection. This is characterised by rapid maturation of larvae within the gut, penetration through the intestinal wall and haematogenous spread. Clinically, this manifests as a multisystemic illness typically including GI features, such as diarrhoea and malabsorption. Common precipitants of the hyperinfection syndrome include immunosuppressive medication, malnutrition, old age and human T-lymphotropic virus type-1 (HTLV-1) (but not typically HIV) infection,2 although this patient was negative for both viruses.
Diagnosis of S. stercoralis may be via stool microscopy, ELISA for serum S. stercoralis IgG or histology. Endoscopic findings in infected patients are widely variable and non-specific, but within the upper GI tract tend to include oedematous, discoloured mucosa.3 Oral ivermectin is the preferred therapy, although the optimal treatment regimen remains uncertain. Where there are concerns regarding malabsorption, parenteral (veterinary) ivermectin may be considered.
Clinicians should consider this diagnosis in patients with unexplained GI disease who have previously resided in regions endemic for strongyloidiasis, even if the original exposure may have been decades earlier. Enteroscopy may be helpful in making the diagnosis.
Contributors JMH proposed the original idea for the manuscript. RT, SJ and BHM wrote the original manuscript. RT, SZ-V and JC were involved in the patient's clinical care. RDG performed histological analysis and RT performed radiological analysis. All authors read and approved the final draft submitted for publication.
Competing interests None.
Patient consent Obtained.
Provenance and peer review Not commissioned; externally peer reviewed.