Malabsorption refers to impaired nutrient absorption in the small intestine. It can affect single nutrients or multiple nutrients. Common causes include celiac disease, inflammatory bowel disease, pancreatic insufficiency, and bacterial overgrowth. Symptoms include chronic diarrhea, abdominal distension, weight loss, and fatigue. Diagnosis involves tests of fat, carbohydrate, vitamin, and mineral absorption. Treatment focuses on correcting nutritional deficiencies and treating any underlying diseases.

1. Malabsorption

2. Background
• A clinical term that refers to the impaired transport of nutrients
across the apical membrane of enterocytes
• The main site of absorption is small intestine
• The digestion or absorption of a single nutrient component may be
impaired (e.g. lactose intolerance due to lactase deficiency).
• When a diffuse disorder, such as celiac disease or Crohn disease,
affects the intestine, the absorption of almost all nutrients is
impaired.

4. Absorption
3 major phases:
• The luminal phase is the stage in which dietary fats, proteins,
and carbohydrates are hydrolyzed and solubilized by secreted
digestive enzymes and bile.
• The mucosal phase relies on the integrity of the brush-border
membrane of intestinal epithelial cells to transport digested
products from the lumen into the cells.
• In the postabsorptive phase, reassembled lipids and other key
nutrients are transported via the lymphatics and portal
circulation from epithelial cells to other parts of the body.

5. Luminal phase
Impaired nutrient hydrolysis
• The resultant deficiencies in lipase and proteases lead to lipid and
protein malabsorption
• The most common cause for impaired nutrient hydrolysis is
pancreatic insufficiency (CF)
• Inactivation of pancreatic enzymes by gastric hyper secretion, as
seen in Zollinger-Ellison syndrome, is another cause.
• Inadequate mixing of nutrients, bile, and pancreatic enzymes, as
seen in rapid intestinal transit, also causes impaired hydrolysis.
• Decreased bile salt synthesis (cirrhosis, biliary obstruction)

6. Mucosal phase
Impaired brush-border hydrolase activity
• Lactase deficiency (Di saccharidase deficiency)
Either primary or secondary, is the most common form of
disaccharidase deficiency.
Secondary lactase deficiency can be result from acute
gastroenteritis , celiac sprue, radiation enteritis, regional
enteritis.

7. Mucosal phase
Epithelial transport defect
• Decreased absorptive surface area, as seen in intestinal
resection of intestinal bypass
• Damaged absorbing surface; infections, inflammation (as seen
in celiac sprue, tropical sprue, Crohn disease)

8. Postabsorptive phase
• Defect in:
- Enterocyte processing or,
- Lymphatic obstruction (eg. congenital intestinal
lymphangiectasia)

9. Causes
 Intestine (Celiacdisease,IBD,postenteritis)
 Pancreaticsecretoryfunction (Cysticfibrosis)
 Hepatobiliarysecretoryfunction
 Lymphatic

10. Clinical
manifestations
• Chronic diarrhea
• Abdominal distention
• Failure to thrive

11. Diarrhea/ steatorrhea
• The most common symptomatic complaint
• Pale, greasy, voluminous, foul-smelling stools
• Anorexia, flatulence, abdominal distension and borborygmi may
be the only complaints

12. Weight loss and fatigue
• Is common and may be pronounced
• Patients may compensate by increasing their caloric
consumption, masking weight loss from malabsorption.
• The chance of weight loss increases in diffuse diseases involving
the intestine, such as celiac disease

13. Other manifestations
• Edema/ ascites: Hypoalbuminemia
• Dermatitis: zinc deficiency/ Niacin deficiency
• Anemia: microcytic/ macrocytic
• Ocular manifestations: vit A deficiency

14. Other manifestations
• Bleeding/ ecchymosis: ? Deficiency
• Osteopenia, pathological fractures: ? deficiency
• Peripheral neuropathy: ? deficiency
• ??: hypocalcemia and hypomagnesemia

15. Physical examination
General:
• Orthostatic hypotension
• Signs of weight loss, muscle wasting, loss of
subcutaneous fat
• Pallor
• Dermatological signs: Ecchymosis, Dermatitis
herpetiformis, Pellagra, alopecia.
• Cheilosis, glossitis, or aphthous ulcers of the mouth,
Peripheral edema

16. Physical examination
Abdominal examination:
• The abdomen may be distended, and bowel sounds
may be hyperactive
• Ascites may be present in severe hypoproteinemia

17. Physical examination
Neuro exam:
• Peripheral neuropathy, or ataxia
• The Chvostek sign or the Trousseau sign

18. Laboratory studies
• Should be guided by patient’s history and physical
examination.
• CBC (microcytic anemia due to IDA or macrocytic anemia
due to vitamin B12 ,(folate) malabsorption)
• Serum iron, vitamin B12, and folate concentrations
• Prothrombin time
• Sweat chloride test
• Electrolytes

19. Laboratory studies
• Hypoproteinemia, hypoalbuminemia in case of prt
malabsorption
• Fat malabsorption often results in fat-soluble vitamin
deficiencies
• ESR elevated in IBD
• Serum antigliadin, anti-endomysial & anti TTG
antibodies

20. Imaging Studies
• An upper gastrointestinal series with small bowel follow-
through, or a CT or MR enterography can provide important
information about the gross morphology of the small intestine
and can identify small bowel diverticula or other anatomic
abnormalities associated with bacterial overgrowth
• CT in case of chronic pancreatitis
• Wireless capsule endoscopy allows for visualization of the
entire small bowel and evaluation of small bowel mucosal
disease

21. Fat malabsorption studies
• Usually the first test obtained because many disease processes
result in fat malabsorption.
• Instruct patients to consume a normal amount (80-100 g/d) of
fat before and during the collection.
• Based on this intake, fecal fat excretion in healthy individuals
should be less than 7 g/d.
• Qualitative: Sudan III stain
• Quantitative: 72-hour fecal fat excretion

22. Carbohydrate absorption studies
• Hydrogen breath test, simple & sensitive
• Patients are given an oral solution of lactose
• In cases of lactase deficiency, colonic flora digest the unabsorbed
lactose, resulting in an elevated hydrogen content in the expired
air.
• Bacterial overgrowth or rapid transit also can cause an early rise
in breath hydrogen, necessitating the use of glucose instead of
lactose to make a diagnosis.
• However, 18% of patients are hydrogen non-excretors, causing a
false-negative test result

23. Upper endoscopy with small bowel mucosal biopsy
• Establishing a definitive diagnosis of malabsorption of the mucosal
phase often can be achieved by histologic examination of biopsied
mucosal specimens obtained during routine upper endoscopy.
• Examples of conditions that can be diagnosed this way
Celiac sprue, giardiasis, Crohn disease, abetalipoproteinemia, and
lymphoma.
• Cobblestone appearance of the duodenal mucosa is seen in Crohn
disease
• Reduced duodenal folds and scalloping of the mucosa may be
evident in celiac disease
• Villous atrophy on histology in certain cases

25. Celiac disease
(Gluten-sensitive enteropathy)
- Can present at ANY age group
- HLA DQ2 or DQ8 haplotypes
- Wheat, Barley, Rye
- Diarrhea, FF, abdominal distension,...
sometimes constipation
- Associated with type I DM, thyroiditis, Down
syndrome
- IDA, unresponsive to Iron therapy
- Dermatitis herpetiformis + other
extraintestinal manifestations ?
- Anti ttg IgA, with total IgA to exclude IgA
deficiency
- Biopsy (villous blunting, intra epithelial
lymphocytosis, crypt hyperplasia)
- Lifelong gluten-free diet

28. Management
• Correction of nutritional deficiencies
• Treatment of the causative diseases

29. Nutritional Support
• Caloric and protein replacement is essential.
• It is crucial to supplement the patient with various
minerals, such as calcium, magnesium, iron, and
vitamins, which may be deficient in malabsorption
• Medium-chain triglycerides can be used as fat
substitutes, because they do not require micelle
formation for absorption and their route of transport is
portal rather than lymphatic.

30. Treatment of causative diseases
• A gluten-free diet helps treat celiac disease
• Lactose intolerance ? ,, (Lactaid also helps)
• The use of protease and lipase supplements are the
therapy for pancreatic insufficiency
• Antibiotics are used to treat small intestinal bacterial
overgrowth
• Corticosteroids, anti-inflammatory agents, such as
mesalamine, and other therapies are used to treat IBD

31. Thank You