Nutrition: Causes of Villous Atrophy

1. Infectious Causes of Villous Atrophy

Whipple’s Disease

Etiology: Tropheryma whipplei, a gram-positive intracellular bacillus.
Epidemiology: Common in middle-aged white males (9:1 male-to-female ratio), associated with HLA-B27.
Symptoms:

Endoscopy: Edematous small bowel walls.
Histology: Jejunal biopsy shows PAS-positive macrophages containing bacilli in the lamina propria (see images below).

Tropical Sprue

Epidemiology: Found in endemic regions like the Caribbean, Southeast Asia, and India.
Symptoms: Chronic diarrhea, steatorrhea, abdominal cramps, and weight loss.
Investigations: Blood tests reveal megaloblastic anemia (low folate and B12), low calcium, and low vitamin D.
Diagnosis: Exclusion of celiac disease and parasitic infections (e.g., Giardia, Strongyloides). Duodenal biopsy shows short, blunted villi with crypt hypertrophy (see images below).
Treatment: Tetracycline for 3–6 months with nutritional supplementation.

Giardiasis

Pathogen: Giardia lamblia, a flagellated protozoan.
Symptoms: Bloating, flatulence, weight loss, and diarrhea that mimics celiac disease.
Diagnosis: Stool microscopy shows kite-shaped trophozoites with flagella (see images below).
Treatment: Single-dose tinidazole or 7-day course of metronidazole.

2. Drug-Induced Villous Atrophy

Neomycin: Affects small bowel mucosa, causing inflammation and atrophy.
Laxative Abuse: Chronic irritation from stimulant laxatives can mimic inflammatory enteropathy (see images below).

3. Immunological Causes

Hypogammaglobulinemia

Clinical Features: Chronic diarrhea, recurrent infections, and malabsorption.
Management: Immunoglobulin replacement therapy.

Cow’s Milk Protein Allergy (in children)

Mimics celiac disease; resolution occurs upon the elimination of cow’s milk protein from the diet.

Specific Infections

Traveler’s Diarrhea (ETEC)

Epidemiology: Common in high-risk areas (Africa, Latin America, Middle East, most parts of Asia).
Clinical Pearls: Avoid bismuth or loperamide in cases of bloody stools or severe cramps.
Management: Consider antibiotics for immunosuppressed patients or symptoms persisting >36 hours.

Enterohaemorrhagic E. coli (EHEC/VTEC/STEC)

Complication: Can lead to hemolytic uremic syndrome (HUS).
Management: Supportive care only; avoid antibiotics to prevent toxin release (see images below).

Strongyloidiasis

Pathogen: Strongyloides stercoralis.
Transmission: Contact with contaminated soil or fecal-oral route.
Symptoms: Mild GI symptoms or severe respiratory distress in hyperinfection.
Diagnosis: Stool microscopy shows larvae; eosinophilia is common (see images below).
Treatment: Ivermectin.

Ascariasis

Epidemiology: Found in Asia, Africa, and South America.
Symptoms: Early-phase eosinophilic pneumonitis (Löffler's syndrome); late-phase intestinal obstruction, anorexia, and nausea.
Treatment: Albendazole or mebendazole (single-dose therapy).

Small Bowel Bacterial Overgrowth (SIBO)

Risk Factors: Post-surgical anatomy (e.g., blind loops) or motility disorders (e.g., diabetes).
Diagnosis: Hydrogen/methane breath test (rise of >20 ppm suggests SIBO).
Treatment: Empirical antibiotics; the BSG recommends a trial of antibiotics rather than relying solely on breath tests.

Conditions such as amyloidosis, inflammatory bowel disease, and SIBO can mimic celiac disease by causing villous atrophy.
Amyloidosis diagnosis may include Congo red staining showing apple-green birefringence (see images below).

References

Images