Malabsorptive

Malabsorptive describes conditions or interventions characterized by impaired absorption of nutrients from the gastrointestinal tract. It can result from mucosal disease such as celiac disease or Crohn's disease, pancreatic exocrine insufficiency, cholestasis or bile acid deficiency, bacterial overgrowth, rapid intestinal transit, or anatomical changes that shorten or bypass absorptive surfaces. In bariatric surgery, malabsorptive procedures reduce nutrient absorption by diverting digested material away from portions of the small intestine, thereby limiting caloric and nutrient uptake. Classic malabsorptive operations include biliopancreatic diversion and, in combination with restriction, biliopancreatic diversion with duodenal switch.

Clinical features include chronic diarrhea or steatorrhea, bloating, weight loss, edema, and signs of micronutrient deficiencies such as anemia, neuropathy, or osteomalacia. The specific pattern depends on which nutrients are poorly absorbed (fat, fat-soluble vitamins; iron; calcium; vitamin B12; others).

Diagnosis relies on clinical history, dietary assessment, stool studies (fecal fat quantification), and laboratory tests for nutrient status. Tests may include fecal fat excretion, D-xylose or lactose tests, and endoscopic evaluation with biopsies when mucosal diseases are suspected. Imaging and breath tests can help identify bacterial overgrowth or structural causes.

Management aims to treat the underlying cause and correct nutritional deficiencies. This often involves pancreatic enzyme replacement, bile acid supplements, targeted vitamin and mineral supplementation, dietary modifications (fat-restricted or medium-chain triglycerides), and monitoring for complications. In post-surgical cases, ongoing nutritional counseling and specialized follow-up are essential to avoid deficiencies.