Snapshot A 60-year-old man presents to his primary care physician for pale, foul-smelling stools. He has a history of alcoholism, though he has not had a drink in a few months. He also has a history of recurrent pancreatitis, requiring multiple admissions. Each episode was treated conservatively. He is scheduled for an abdominal computed tomography (CT), which shows inflammation and calcium deposits in the pancreas, suggesting chronic pancreatitis. He is started on enzyme replacement therapy for pancreatic insufficiency. Introduction Overview malabsorption syndromes inability to absorb macronutrients or micronutrients often associated with chronic diarrhea and result in nutritional deficiencies treatment is targeted at correcting the underlying disorder Epidemiology etiology fat malabsorption celiac disease Whipple disease infection with Tropheryma whipplei pancreatic insufficiency tropical sprue cause unknown but thought to be due to microorganisms in the tropics lactose intolerance bile salt deficiency short bowel syndrome Pathogenesis mechanism impairment in absorption of nutrients due to a variety of defects in intestinal mucosa malabsorption of fat-soluble vitamins vitamins A, D, E, and K vitamin B12 deficiency destruction of terminal ileum loss of pancreatic enzymes that aid in B12 absoprtion lactose intolerance lactase deficiency colonic bacteria ferment lactose and cause decreased stool pH, resulting in osmotic diarrhea Presentation History easy bruising Symptoms common symptoms frequent and loose watery stools lactose intolerance pale, bulky, foul-smelling stools fat malabsorption abdominal pain and flatus bloating and weight loss vitamin deficiencies Vitamin Deficiencies Vitamin A Deficiency Vitamin D Deficiency Vitamin E Deficiency Vitamin K Deficiency Night blindness Xeroderma Osteomalacia Rickets Hemolytic anemia Muscle weakness Paresthesias Bleeding Easy bruising Imaging Abdominal computed tomography indications evaluate for chronic pancreatitis Studies Serum labs hypocalcemia ↑ prothrombin time/INR vitamin K malabsorption autoantibodies for celiac disease anemia microcytic or macrocytic depending on etiology of malabsorption syndrome Invasive studies Sudan black stain of stool stains and detects fat 72-hour fecal fat test most sensitive small bowel biopsy indication diagnosis of celiac disease, Whipple disease, or tropical sprue findings celiac disease villous atrophy, crypt hyperplasia, and lymphocytosis Whipple disease PAS-positive organisms with foamy macrophages in intestinal lamina propria tropical sprue microorganisms lactase deficiency normal villi lactose hydrogen breath test indication lactose intolerance testing D-xylose absorption test indications diagnosis of small intestine malabsorption distinguishes from pancreatic disorders findings abnormal D-xylose testing indicates that villous lining is destroyed or impaired, resulting in malabsorption of D-xylose Differential Fat Malabsorption Syndromes Celiac Disease Whipple Disease Pancreatic Insufficiency Tropical Sprue Fat malabsorption Pale, bulky, and foul-smelling stools Pale, bulky, and foul-smelling stools Pale, bulky, and foul-smelling stools Pale, bulky, and foul-smelling stools Unique clinical features Positive autoantibodies Dermatitis herpetiformis Triad cardiac symptoms arthralgia neurologic symptoms Caused by Tropheryma whipplei, a gram-positive rod History of alcoholism History of previous episodes of pancreatitis History of being in tropical regions Negative autoantibodies Megaloblastic anemia due to folate and vitamin B12 deficiences Diagnostic testing Small bowel biopsy Abnormal D-xylose test Autoantibodies Small bowel biopsy Polymerase chain reaction of stool showing T. whipplei Abnormal D-xylose test Abdominal CT scan Secretin stimulation testing Small bowel biopsy Abnormal D-xylose test Treatment Dietary restrictions avoid gluten Ceftriaxone Trimethoprim/sulfamethoxazole Tetracycline Enzyme replacement therapy Doxycycline Trimethoprim/sulfamethoxazole Treatment Lifestyle dietary restriction indication celiac disease modality avoid gluten Medical treat underlying condition antibiotics indication whipple disease tropical sprue drugs tetracycline doxycycline ceftriaxone trimethoprim/sulfamethoxazole enzyme replacement therapy indication chronic pancreatitis lactose intolerance nutrition replacement therapy indication vitamin deficiencies Surgical none Complications Malnutrition