Malabsorption syndrome

Disease Description (Causes and Symptoms)

• Definition summary: A collective term for conditions in which abnormalities occur in one or more stages of digestion and absorption, resulting in insufficient absorption of nutrients (such as carbohydrates, proteins, fats, vitamins, and minerals) in the intestines.
• Main causes: Biliary obstruction (reduced bile flow), chronic pancreatitis·pancreatic insufficiency (digestive enzyme deficiency), small intestinal bacterial overgrowth (SIBO), short small intestine (short bowel, e.g., a remaining length of ≲100 cm after small-intestinal resection), small-intestinal mucosal damage (e.g., villous atrophy due to celiac disease), lymphatic obstruction, radiation enteropathy, infection, etc.
• Pathophysiology summary: Nutrients cannot enter the body because digestion·hydrolysis is insufficient or the absorptive surface/function of the intestinal mucosa is damaged → causes various symptoms including weight loss·nutritional deficiencies·steatorrhea·electrolyte, protein, and fat-soluble vitamin deficiencies.
• Main symptoms: Chronic diarrhea, large amounts of fatty stool (fatty stool/steatorrhea), weight loss, abdominal bloating·abdominal pain, muscle wasting, edema (hypoalbuminemic), bleeding tendency (vitamin K deficiency), anemia (iron·folate·vitamin B12 deficiency), skin changes, neurological symptoms (vitamin B1/B12 deficiency), osteomalacia/osteoporosis, etc.

Treatment Methods (Standard Treatment · Medication · Procedures/Surgery · Lifestyle Management) and Precautions

• Basic principles: Stabilization of nutritional status + treatment of the cause + replacement of deficiencies
• Acute/severe nutritional support
  • If necessary, supplement calories·protein·electrolytes through parenteral nutrition (total parenteral nutrition, TPN) or central venous nutrition.
• Cause-specific treatment
  • Pancreatic insufficiency: Oral pancreatic enzyme replacement therapy (such as pancreatin) — taken together with meals to improve fat digestion.
  • Small intestinal bacterial overgrowth (SIBO): Suppression of bacteria with appropriate antibiotics (e.g., rifaximin, according to clinical judgment).
  • Biliary obstruction/reduced bile flow: If biliary obstruction is the cause, securing biliary drainage (endoscopic·surgical treatment), etc.
  • Short bowel (short small intestine): Support of intestinal function (nutritional support, promotion of intestinal adaptation); in severe cases, consider intestinal transplantation (limited application).
  • Celiac disease and other mucosal disorders: Treatment according to the underlying disease (e.g., strict gluten-free diet for celiac disease).
• Nutritional·medication supplementation
  • Supplement fat-soluble vitamins (A, D, E, K) and water-soluble vitamins (as needed).
  • Supplement iron, folate, and vitamin B12 (consider injection administration when malabsorption is present), and calcium·vitamin D (for bone health).
  • Protein supplementation and, if necessary, high-calorie intravenous fluids.
  • When fat absorption is severely impaired, manage the diet by including medium-chain triglycerides (MCTs) (medium-chain fats are less dependent on absorption).
• Lifestyle management
  • Small, frequent meals, fat control, adequate calorie intake, and limiting alcohol (in pancreatic-related cases).
  • Regular monitoring of weight·symptoms·blood tests.
• Precautions (complication risks and points to note during self-management)
  • Vitamin·mineral deficiencies may cause bleeding·anemia·fractures·neurological symptoms → regular evaluation and timely supplementation are necessary.
  • Long-term TPN may cause catheter-related infections, changes in biliary·bile metabolism, and liver-function abnormalities.
  • Be alert to side effects and resistance during antibiotic treatment.
  • Self-treatment (indiscriminate use of supplements) may instead cause problems with absorption rates·drug interactions.

Checklist Before an Outpatient Visit (Including Items to Bring · Records · Example Questions)

• Items to bring
  • A list of all medications·supplements currently being taken (including doses·administration times).
  • Recent blood test·imaging test results (if possible, a printed copy or summary of the electronic medical record).
  • A record of weight changes and current weight (comparison with the past several months is helpful if available).
  • Bowel movement diary: Number of episodes of diarrhea·stool characteristics (watery/oily film/foul odor)·amount, and whether abdominal pain·bloating is present.
  • Food diary (usual diet, foods that cause problems, etc.).
• Symptom checklist to write down in advance for the outpatient visit
  • When symptoms began and their course (gradual/acute).
  • Whether deficiency-related symptoms such as night blindness·skin bleeding·weakness·low body temperature·numbness in the hands and feet are present.
  • History of intestinal surgery (including the length resected), history of radiation therapy, and history of chronic pancreatitis·hepatobiliary disease.
• Preparation for tests that may be performed during the outpatient visit
  • Stool fat test (72-hour stool fat, presence of steatorrhea), blood tests (albumin·electrolytes·iron·vitamin levels·prothrombin time, etc.), and if necessary, a D-xylose absorption test·small-intestinal endoscopy·mucosal biopsy·breath tests (fructose or glucose breath test for SIBO), etc.

Examples of General Questions to Ask the Doctor

• "What are the expected effects and side effects of this treatment (or medication)?"
• "How concerning is my nutritional status (weight·blood test results, etc.), and what is the prognosis?"
• "What specifically must I change in daily life, such as diet·exercise·alcohol consumption?"
• "What additional tests do I need, and what is their purpose?"

Examples of Disease-Specific Questions

• If pancreatic insufficiency is suspected: "If you prescribe pancreatic enzymes for me, what dose should I take with each meal, and how should I take it? How quickly will the effects appear?"
• If small intestinal bacterial overgrowth is suspected: "Do I need to be evaluated through SIBO testing? How often and how many times would antibiotic treatment need to be repeated?"