This is a case report of patient OG 70, which looked for assistance at the Hospital de Clinicas de Porto Alegre (HCPA) by fatigue, dyspnea, vomiting and diarrhea. Patient had undergone intestinal resection 5 years ago by strangulated abdominal hernia, came up with gastrointestinal symptoms and progressive weight loss. On admission, showed malnutrition and clinical and echocardiographic signs suggestive of heart failure (HF), with probable diagnosis of IC by thiamine deficiency. Thiamine replacement was initiated 300mg, EV, per day. The patient was also managed with replacement of electrolytes, antibiotics for bacterial overgrowth, antiparasitic, and oral diet with low osmolarity, lactose free, low in sucrose. Replacement of zinc and B vitamins were also accomplished. The patient was discharged after 30 days of hospitalization with clinical improvement and without clinical signs of HF. Conclusion: Deficiency of vitamin B1 should be investigated in patients with malnutrition and Short Bowell Syndrome, especially those with cardiac and neurological expressions characteristic of beriberi. The treatment of thiamine deficiency is relatively simple and leads to rapid improvement of symptoms
