Tropical Sprue

  • Definition:
  • – Intestinal mucosal disease characterized by malabsorption of 2 or more unrelated nutrient groups (carbohydrate, protein, vitamins) for which other known causes of malabsorption had been excluded
  • Pathophysiology:

 

  •             Clinical features
  • – Chronic diarrhea
  • – Steatorrhea (pale, bulky, frothy and foul smelling stool)
  • – Rarely bloody diarrhea
  • – Weight loss
  • – Abdominal distension, borborygmi are very prominent features
  •                  
  •                 Physical examination:
  • – Anemia: Most often megaloblastic due to vitamin B12/Folic acid deficiency. coexisting iron deficiency may cause dimorphic anemia
  • – Angular stomatitis, cheilitis, glossitis due to vit. B deficiency
  • – Hyperpigmentation of buccal mucosa, palm and knuckle (due to disturbed melanin metabolism due to vit. B12 malabsorption)
  • – Gross emaciation
  • – Fever
  • -Peripheral neuropathy : SCD not seen nowadays
  • – Rarely Ogilvie’s syndrome
  • Features that distinguish Tropical sprue from Celiac disease: 
  • – H/O of exposure to an endemic area
  • – Anti tTG/ EMA absent
  • – Vitamin B12 deficiency is more common
  • – No response to gluten free diet
  • – Response to treatment with Folic acid antibiotics in most cases
  • – Biopsy histology does not distinguish between tropical sprue and celiac disease
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  •                                   Diagnosis:
  • – As there is no specific diagnostic test for tropical sprue, the diagnosis relies on excluding celiac disease and other diseases that causes malabsorption including protozoal infection which can cause similar symptoms and by demonstrating the characteristic alterations in small intestinal mucosal histology
  • – Although tropical sprue typically is a disease of the small intestine, involvement of the stomach and colon has been reported
  • – More than half of patients with tropical sprue have atrophic gastritis

 

  •                           Histology of small intestinal mucosa:
  • –  It is standard to obtain biopsies from the distal duodenum(3rd and 4th part) or proximal jejunum during upper GI endoscopy
  • – Non-specific lesion of variable severity, which may involve the length of the small intestine in patchy fashion
  • – Varying degrees of villus shortening (atrophy) and crypt elongation
  • – Complete villus atrophy, noted in some patients with celiac disease, is not seen in tropical sprue
  • – The lamina propria of the small intestine is infiltrated by lymphocytes, and there is an increase in intraepithelial lymphocytes (IEL)
  • – Histologic lesions cannot be distinguished with certainty from that observed in celiac disease, viral gastroenteritis, or intraluminal bacterial overgrowth

 

  •                      Endoscopic finding:
  • – Scalloping of the duodenum (due to mucosal atrophy and loss of villus pattern)
  •     Tests for malabsorption:
  • -Fecal fat estimation
  • – Vitamin B12 and folate and testing for d-xylose absorption
  • – 2 abnormal tests in the appropriate setting are consistent with tropical sprue in the absence of other causes of malabsorption
  •      
  •                 Small bowel follow through
  • – Thickening of the mucosal folds of the jejunum
  • – Loss of the feathery mucosal pattern in the proximal jejunum
  • – Delayed transit through the small intestine
  •        
  •                            CT scan of abdomen
  • – Dilated, featureless, atonic loops of small intestine with dilution of oral contrast, that suggests a hyper secretory state
  • – Done to exclude intestinal masses and lymphadenopathy within the mesentery and retroperitoneum, which are characteristic of other inflammatory and infectious diseases, such as TB, lymphoma, parasitic infestations, and eosinophilic enteritis
  •        
  •                  Double-balloon or single-balloon enteroscopy
  • – To exclude secondary causes of malabsorption
  • – Aerobic and anaerobic culture of the small intestinal contents aspirated either during endoscopy or by a jejunal tube
  • – To exclude SIBO (Fasting counts exceeding 105 bacteria/mL of jejunal flid indicate bacterial overgrowth)

 

  •                        TREATMENT OF TROPICAL SPRUE
  • – Correction of dehydration and electrolyte imbalance
  • – Correction of Calcium, Magnesium, Vitamin D, Vitamin B12, Folic acid
  • – A high-calorie, high-protein, fat-restricted diet
  • – Restriction of long-chain fatty acids and its substituted by medium-chain TGs to reduce diarrhea and steatorrhea
  • Tetracycline 250 mg 4 times daily (or doxycycline 100 mg once daily) for 3 to 6 months
  • – Relapses of disease after completion of therapy are uncommon, and recurrent symptoms require investigation to exclude other causes, especially intestinal lymphoma

 

 

 

 

 


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