Editor’s Quiz: GI Snapshot

An unusual cause of weight loss in a man from West Africa

Rabia Topan1*, Sophie James1, Benjamin H Mullish1, Sagen Zac-Varghese2,Robert D Goldin3, Robert Thomas4, Jeremy Cox2, Jonathan M Hoare1

1Department of Gastroenterology;2Department of Endocrinology; 3Department of Histopathology; 4Department of Radiology; all at St Mary’s Hospital, Imperial College Healthcare NHS Trust, South Wharf Road, London, W2 1NY, United Kingdom.

*Corresponding author. Contact Dr Topan via:

Department of Gastroenterology

St Mary’s Hospital

ImperialCollege Healthcare NHS Trust

South Wharf Road

London

W2 1NY

UK

Telephone: +44 (0)20 331 21208

Fax: +44 (0)20 331 26871

Email:

Keywords: enteroscopy; malabsorption; parasitic diseases

Word count:

Clinical presentation:

A 71-year-old man was investigated for recent unintentional weight loss of approximately 15 kg (>20% total body mass) within the past three 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 Leonewith no recent travel history.

Examination revealed cachexia and lymphadenopathy. Admission blood tests demonstrated a white blood cell count of 12.1 x 109/l (with eosinophil level raised at 1.0 x 109/l), microcytic anaemia (haemoglobin of 109 g/l with 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 1cm 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).

Question:

What is the underlying diagnosis?

Answer:

Histology of jejunal biopsies demonstrated larvae of Strongyloides stercoralis (figure 3) whilst stool assays were also positive,together confirming the diagnosis of Strongyloides hyperinfection. Despite treatment with oral ivermectin, the patient developed multi-organ failure from disseminated infection and died.

Strongyloides is a roundworm endemic in tropical and suptropical regions includingSierra Leone, where the prevalence is estimated at more than 25%[1]. Transmission is through direct penetration of skin by infected larvae whilst 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 ofprogression 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 multi-systemic illness typically including gastrointestinal features, such as diarrhoea and malabsorption. Common precipitants of the hyperinfection syndrome include immunosuppressive medication, malnutrition, old age and HTLV-1 (but not typically HIV) infection[2], although this patient was negative for both viruses.

Diagnosis of Strongyloides may be via stool microscopy, ELISA for serum Strongyloides IgG, or histology. Endoscopic findings in infected patients are widelyvariable and non-specific, but within the upper gastrointestinal tracttend 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 gastrointestinal 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 andRT performed radiological analysis. All authors read and approved the final draft submitted for publication.

Competing interests:

None.

Patient consent:

Consent obtained from next of kin.

Figures:

Figure 1: Enhanced CT slice acquired at the L3 level, demonstrating concentric bowel wall thickening (white arrow), most marked within the jejunum. There is relative sparing of the large bowel with no evidence of intramural gas. Ascites is also seen.

Figure 2: (A) Initial endoscopic view of jejunum and (B) close-up view, demonstrating engorged, oedematous villi.

Figure 3: Histology from the jejunal biopsy (H&E stain), demonstrating larva (full arrow) and eggs (arrowhead) of Strongyloides stercoralis.

References:

1 Schär F, Trostdorf U, Giardina F, et al. Strongyloides stercoralis: Global distribution and risk factors. PLOS Negl Trop Dis2013;7(7):e2288.

2 Satoh M, Kiyuna S, Shiroma Y, et al. Predictive markers for development of strongyloidiasis in patients infected with both Strongyloides stercoralis and HTLV-1. Clin Exp Immunol 2003;133(3):391-396.

3. Thompson BF, Fry LC, Wells CD, et al. The spectrum of GI strongyloidiasis: an endoscopic-pathologic study. Gastrintest Endosc 2004;59(7):906-910.