[Review of pathophysiology and diagnosis of irritable bowel syndrome]

Irritable bowel syndrome is one of the most common functional gastrointestinal disorders with the prevalence of 10-20% of the world's population. This syndrome usually manifests as abdominal pain or discomfort associated with altered bowel habits, and it is usually diagnosed based on patient's history and there is no specific diagnostic test for it. However, it should be noted that definitive diagnosis is made after ruling out other organic diseases. The most common clinical manifestations are abdominal pain or discomfort, constipation, diarra or alternating constipation and diarrhea, and abdominal bloating. Various mechanisms have been described for pathogenesis of this disorder, including motor dysfunction, visceral hypersensitivity, mild inflammation, and stress. Genetic factors seem to be involved in inflammation and regional immune responses and subsequently, susceptibility to IBS. But it seems that several factors are involved in the presentation of IBS symptoms. Although most patients do not refer for medical care, the disease imposes a considerable cost on patient and healthcare system and considerably overshadows the subject's quality of life. Having knowledge about the precise pathophysiology and diagnostic criteria are necessary for better identification of patients and choosing a more appropriate treatment approach.

Isolated vitamin B12 deficiency due to pernicious anemia in a patient with celiac sprue: a case report

Celiac sprue or Celiac disease is an autoimmune enteropathy often seen in patients are sensitive to gluten. Usually due to impaired absorption of iron and folic acid at the proximal of small intestine, iron deficiency anemia and megaloblastic anemia is common, but vitamin B 12 deficiency is rarely reported. We will describe the case that in addition to have celiac disease, without deficiency of iron and folic acid, has deficient vitamin B 12 due to severe pernicious anemia and improved dramatically to treatment with injection of vitamin B12. 38-years-old male patient with complaints of weakness and malaise and abdominal pain is referred. Initial tests indicated patient have megaloblastic anemia caused by vitamin B12 deficiency. With stomach and deuodenal biopsy and serological antibody titration studies including anti-parietal cell antibody, anti-endomysial antibody and tissue transglutaminase, accompanied with pernicious anemia and celiac disease was proved. After diagnosis, patients treated with intramuscular vitamin B12 and regimen without gluten, after one month significant improvements in clinical symptoms and laboratory found