A 30-year-old male came with complaints of increased frequency of stools on and off for two years and significant weight loss since one year. He reported recurrent episodes of stools that were semisolid to watery, 4 to 6 times a day, and were unrelated to a specific food or diurnal variation. He denied any blood or pus in the stool; or fever and vomiting but reported occasional abdominal discomfort. The patient reported the stools as bulky and foul-smelling. His stool frequency decreased with treatment, but only for a short duration. The patient also experienced significant weight loss, approximately 12 to 15 kg, and easy fatigability during the past year. He denied any history of major illness, jaundice, tuberculosis, joint(s) pain, diabetes, or constipation, specifically after a bout of diarrhea. 

The patient had consulted many primary care physicians in the past for his ailment, and his medical reports suggested the use of antimicrobial agents, iron and multivitamins, antisecretory agents, etc. He also had received two units of blood for anemia six months from the date of admission to the hospital. He used to consume alcohol occasionally but stopped since the onset of this illness. 

Examination revealed the patient to be moderately built but cachectic, with pale conjunctiva. No icterus, clubbing, cyanosis, palpable lymph nodes, or edema was noted. His height was 176cm, contrasting his weight of 42 kg. He displayed normal vitals, a soft- non-tender abdomen, and no organomegaly. 

The patient displayed hemoglobin as 8.9g/dl, RBC count as 2.670000/cumm, total WBC count as 6300/cumm, with a differential count of N64/ L33/ M02/ E01/B00; ESR as 60 mm/ 1st hour; normal platelet count; mean corpuscular volume (MCV) as 111.1fl, a mean hemoglobin concentration as 33.4pg and MCHC as 30.1g/dl. His peripheral smear examination showed a consistent, megaloblastic picture. He also displayed total Proteins as 5.7g/dl, with Albumin - 2.8g/dl and Globulin- 2.9g/dl; normal chest X-ray; negative serum HIV and HBsAg; stool fat (24hrs) around 10%; no ova or cyst of any parasite in stool; negative Stool culture for organisms. 

His upper GI endoscopy was unremarkable. The barium meal follow-through study displayed thickened ileal loops and flocculation of the barium. The fluoroscopic study showed Sluggish peristalsis. A biopsy taken from the last part of the duodenum showed marked atrophy of the surface villi, with vacuolar degeneration and an increased number of intraepithelial lymphocytes in the surface epithelium. The nuclei of epithelial cells showed marked atypical enlargement, indicating megaloblastic changes. 

The clinical features and investigations suggested the diagnosis as tropical sprue; which is a clinical entity of unknown etiology, presenting with an acquired chronic diarrhoeal illness and malabsorption.

The patient received 250mg of Tetracycline PO q6h for six months, along with nutritional supplementations in the form of folic acid 5mg PO OD with iron, calcium, vitamin C, and vitamin B12 supplements, considering severe nutritional deficiency. 

The treatment benefitted the patient with a weight gain of 1kg on the fifteenth day, 4 kg at one month, and 12 kg at six months from discharge. 

Shah V, Patel T. A Case Of Malabsorption Syndrome (MAS) Due To Tropical Sprue. Journal of Clinical and Diagnostic Research.2009;3.