Ray - Malabsorption Flashcards

1
Q

What is the difference b/t malabsorption and maldigestion?

A
  • MALABSORPTION: impaired absorption of nutrients
  • MAL-DIGESTION: impaired digestion of nutrients
  • Clinically, this distinction does not matter -> simply refer to malabsorption
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the 3 steps to normal nutrient absorption?

A
  • Luminal and brush border processing
  • Absorption into intestinal mucosa
  • Transport into the circulation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the difference b/t global and partial malabsorption?

A
  • GLOBAL: reduced mucosal involvement or reduced absorptive surface
    1. Not having enough bowel, or defect throughout the bowel
  • PARTIAL: interferes with the absorption of specific nutrients
    1. B12: need intrinsic factor from stomach (gastrectomy) and terminal ileum (Crohn’s)
    2. Bile acids: terminal ileum
    3. Fe2+, Mg2+, Ca2+, absorbed in duodenum (2+ ions): deficiencies in some bypass surgeries
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the clinical features of global malabsorption?

A
  • CLASSIC: diarrhea
    1. Pale, voluminous, foul-smelling stools
    2. Weight loss
  • “Classic” symptoms are actually quite uncommon, and the more SUBTLE SYMPTOMS are:
    1. Anorexia
    2. Flatulence
    3. Abdominal distention
    4. Borborygmi: rumbling, gurgling noise made by movement of fluid or gas in the intestines
    5. Iron deficiency or osteopenia
  • NOTE: can mimic IBS
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the 8 categorical causes of malabsorption?

A
  • Gastric disease
  • Pancreatic disease
  • Liver/biliary disease
  • Lymphatic disease
  • Intestinal disease
  • Neuroendocrine tumors
  • Endocrine causes
  • Systemic disease
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are some gastric causes of malabsorption?

A
  • Atrophic gastritis
  • Auto-immune gastritis: pernicious anemia
  • Gastric resection
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are some pancreatic causes of malabsorption?

A
  • Congenital enzyme deficiency
  • Pancreatic insufficiency:
    1. Chronic pancreatitis
    2. Cystic fibrosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are some liver and biliary causes of malabsorption?

A
  • Inborn errors of bile transport
  • Cirrhosis
  • Biliary tumors
  • Primary and secondary sclerosing cholangitis (can occur in Crohn’s)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are some lymphatic causes of malabsorption?

A
  • Primary intestinal lymphangiectasia: pathologic dilation of lymph vessels
  • Secondary:
    1. Lymphoma
    2. Solid tumors
    3. Thoracic duct trauma or obstruction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are some intestinal causes of malabsorption?

A
  • Amyloidosis
  • Celiac sprue, tropical sprue, food allergies
  • Crohn’s
  • Graft vs. host disease
  • Intestinal infections
  • Radiation enteritis
  • MANY others
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are some NE tumor causes of malabsorption?

A
  • Carcinoid syndrome
  • Glucagonoma
  • ZE syndrome: gastrinoma
  • Somatostatinoma
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are some endocrine causes of malabsorption?

A
  • Addison’s disease
  • Diabetes
  • Hypothyroidism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are some systemic causes of malabsorption?

A
  • Scleroderma
  • Lupus
  • Neurofibromatosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How do you begin to determine the cause of pt’s malabsorption?

A
  • HISTORY
    1. Alcohol use
    2. Prior surgeries
    3. Relation of symptoms to diet
    4. Abdominal pain
    5. History of ulcers
    6. Diabetes
    7. Medications
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What labs should you look at in pt with malabsorption?

A
  • CBC
  • Iron, B12, folate
  • Albumin
  • Ca, Vit. D
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the most commonly used indicator of global malabsorption? Tests?

A
  • FAT: most complex process of absorption of the macronutrients, so tends to be most sensitive to interference from disease process
    1. Most calorically dense macronutrient, so its malabsorption is a critical factor in the weight loss often seen in malabsorptive disorders
  • TESTS:
    1. Qualitative: Oil red “O”/Sudan stain
    2. Quantitative: 72-hr stool fat collection (gold standard, but rarely done in practice)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How does the 72-hr stool fat assessment work?

A
  • QUANTITATIVE: >6g/d of fat is pathologic bc in stool fat excretion in healthy ppl usually <6g/d
  • Pts w/steatorrhea usually have >20g daily: modest INC in fecal fat does not diagnose steatorrhea
  • GOLD STANDARD, but rarely done in practice (compliance issues; cumbersome and messy)
  • NOTE: stool fat remains constant with high fat diets, even >125g of fat daily
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the qualitative stool fat assessment?

A
  • Oil red “O”/Sudan stain: stain for fat globules from a spot stool sample can detect >90% of pts with steatorrhea
  • Sudan stain: fat stains orange (can stain all kinds of colors, according to Dr. Gupta)
  • See attached image
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Besides fat, what other macronutrient test can be used to assess malabsorption?

A
  • CARBOHYDRATES: can rely on fermentation of undigested carbs by intestinal bacteria, or direct measurement of absorption of specific nutrients
  • Examples: lactose tolerance test and several breath tests that measure hydrogen or radioactive isotopes from sugars containing radionuclide carbon analogues
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What “other” diagnostic tests (incl. radiologic) can be done for malabsorption (aside from fat, carbs)?

A
  • Upper endoscopy with biopsy
  • Colonoscopy with ileal intubation (or biopsy)
  • ERCP (endoscopic retrograde cholangio-pancreatography): images of bile & pancreatic duct
  • Radiologic studies:
    1. CT scan
    2. Small bowel follow-through: x-ray that follows passage of barium through stomach and into the small intestine
    3. MRCP: magnetic resonance cholangio-pancreatography uses MRI to visualize biliary and pancreatic ducts in non-invasive manner
21
Q

What might this be?

A
  • CELIAC SPRUE: notice the “scalloping”
  • Doesn’t make the dx: need to take a biopsy
22
Q

What is going on here?

A
  • Terminal ileum in normal (left) vs. CROHN’s (right)
23
Q

What might this be?

A
  • CHRONIC PANCREATITIS: this is an ERCP (images taken while patient is on a fluoroscopy table)
  • Scope can be seen on B: filling pancreatic duct with dye
  • Dilated, strictures, torturous: probably chronic pancreatitis
24
Q

What do you see here?

A
  • EUS of normal pancreas vs. CHRONIC PANCREATITIS: dilated pancreatic duct, and body of pancreas calcified, much more heterogeneous
  • US from inside the digestive tract
  • Can biopsy mass through this endoscope too
25
Q

Name 4 common causes of malabsorption.

A
  • Celiac sprue
  • Lactose intolerance
  • Bacterial overgrowth
  • Chronic pancreatitis
26
Q

What is celiac sprue? Diagnosis?

A
  • Autoimmune disorder of small bowel due to intolerance of gluten
    1. Leads to global malabsorption, but symptoms can be subtle
  • DX: tissue transglutaminase IgA
    1. Total IgA: if pan-deficient in IgA, will not have TTG IgA (and have 5x risk)
    2. Small bowel biopsy -> confirms diagnosis, regardless of the results of these first 2 tests
    3. Can be diagnosed with nothing more than iron deficiency anemia
  • Good to have dietitian help in tx of these pts
  • Susceptible to bone loss
  • NOTE: these tests must be done while pt is taking gluten in their diet
27
Q

What condition do you see here? Describe the characteristic histopathology and dx technique.

A
  • TOP: normal intestinal mucosa
  • BOTTOM: celiac disease
  • Biopsy specimens from duodenum are generally diagnostic in celiac disease
  • Histopathology is characterized by:
    1. INC #’s of intraepithelial CD8+ T lymphos (intraepithelial lymphocytosis)
    2. Crypt hyperplasia
    3. VILLOUS ATROPHY
  • Probably takes awhile for the severe appearance on front of card, so INC #’s of CD8+ T-lymphos in tops of villi is what pathologist looks for -> see attached image
28
Q

What is going on here? HIsto? Associated GI condition?

A
  • Dermatitis herpetiformis: red, itchy, punctate lesions
    1. Clefts filled with neutrophils (see attached image of histo)
  • Associated with CELIAC DISEASE
29
Q

What do you see here?

A
  • Enteropathy-associated T-cell lymphoma: sheet of lymphos that eat up crypts/glands
  • Associated with CELIAC DISEASE
30
Q

What is lactose intolerance? Symptoms and epi?

A
  • Intolerance of lactose-containing foods: primarily dairy products
    1. Caucasians have abnormal persistence of lactase: only during childhood in most races (tolerance wanes with age)
  • SYMPTOMS: bloating, abdominal pain, diarrhea, flatulence after ingestion of dairy products
  • EPI: only 7-20% of Caucasians
    1. 80-95% of Native Americans
    2. 60-75% of Africans
    3. Up to 90% in parts of Asia
31
Q

How does lactose digestion work?

A
  • Lactose hydrolyzed by intestinal lactase to glu + galactose, and these 2 monosaccharides are then absorbed by intestinal mucosa
    1. Lactose not absorbed in the small bowel can be absorbed in the colon
  • In colon, lactose converted to short-chain fatty acids (SCFA’s) + hydrogen gas -> the fatty acids are absorbed by the colonic mucosa
    1. Production of hydrogen by colonic bacteria basis of the lactose breath hydrogen test used to diagnose lactose maldigestion
32
Q

How is lactose intolerance diagnosed?

A
  • History: this alone can be just fine to dx
  • Lactose tolerance test
  • Lactose hydrogen breath test
33
Q

How does the lactose tolerance test work?

A
  • Oral admin of 50g lactose, and blood glu levels monitored at 0, 60, and 120 minutes
  • Positive test = blood glu INC <20mg/dL + devo of symptoms
  • NOTE: this test is “not done”
34
Q

How does the lactose hydrogen breath test work?

A
  • Easy to perform, so it has largerly replaced the lactose tolerance test
  • Give 25g oral lactose -> breath hydrogen measured at baseline and 30-min intervals for 3 hrs
    1. Hydrogen values >20 ppm are diagnostic
  • NOTE: you can even order these tests over the internet and have them mailed to your home (see attached image)
35
Q

What is the tx for lactose intolerance?

A
  • Avoidance of dairy products
  • Replacement of lactase
  • Supplemental Ca and Vit. D
36
Q

What is small bowel bacterial overgrowth (SBBO)? Associations?

A
  • Condition in which non-native and/or native bacteria are present in INC #’s
    1. Results in excessive fermentation, inflam, or malabsorption
    2. Small bowel is relatively sterile: ileocecal valve, motility, pylorus keep bacterial growth here to a minimum
  • Associated with:
    1. Anatomic abnormalities: surgical loops (blind loops of bowel), strictures
    2. Abnormal small bowel motility: DM, scleroderma, radiation enteritis
    3. Abnormal communication in small bowel: fistulas, don’t have ileocecal valve, pylorus
    4. Others: chronic pancreatitis, cirrhosis, ESRD, TPN use in children
37
Q

How is SBBO diagnosed?

A
  • Suspected by history
  • Can give empiric trial of antibiotics: improvement can last months
  • Carbohydrate breath tests: can use lactulose, glucose, D-xylose (2 peaks = (+) result)
    1. (+) results will see early peak from hydrogen production in small bowel, then later peak from hydrogen production in colon -> normal result is peak only after 2-3 hours in colon
38
Q

How is SBBO treated?

A
  • Trial of antibiotics: can treat with 7-10 day course with lasting results
    1. Rifaxamin is a non-absorbed, expensive AB: few side effects, and low risk of resistance
  • Treat underlying disorder:
    1. Motility agents
    2. Surgical correction
39
Q

What is chronic pancreatitis? Symptoms?

A
  • Condition of progressive inflammatory changes leading to structural damage
  • Contrasts with acute pancreatitis: recurrent bouts of acute can progress to chronic
  • SYMPTOMS: abdominal pain
    1. Pancreatic insufficiency: does not occur until 90% of pancreatic function is lost -> fat malabsorption, diabetes
40
Q

How is chronic pancreatitis diagnosed?

A
  • HISTORY: chronic alcohol abuse
  • FECAL ELASTASE: most sensitive and specific, esp. in early phases of pancreatic insufficiency
    1. <200mcg/g suggestive of pancreatic insufficiency
    2. Independent of pancreatic enzyme replacement tx, and require only single random stool sample
  • IMAGING studies: CT, MRI, MRCP, EUS
41
Q

How is chronic pancreatitis treated?

A
  • Cessation of alcohol intake: hardest part
  • Pain management
  • Enzyme replacement: pill forms
  • Surgical procedures: to relieve blocked pancreatic duct (not very common)
42
Q

What is Whipple disease? Dx? Histo? Tx?

A
  • Rare, multivisceral chronic disease presenting with malabsorption, lymphadenopathy, and arthritis
    1. Middle-aged pts with weight loss, diarrhea, pain, and arthropathy -> when you see this, think Whipple
    2. Test of choice is biopsy of small bowel
  • HISTO: foamy macros and large #’s of argyrophilic rods in lymph nodes
    1. G(+) actinomycete (Tropheryma whippelii)
  • TX: prolonged course of AB’s (1-2 years of tx)
43
Q

What is going on here? Pathogenesis? Stain?

A
  • Dense accumulation of distended, foamy macros in small intestinal lamina propria -> Whipple’s
  • Clinical symptoms bc organism-laden macros accumulate in small intestinal lamina propria and mesenteric lymph nodes, causing lymphatic obstruction
    1. Malabsorptive diarrhea due to impaired lymphatic transport
  • PAS positive and diastase resistant (see attached image)
44
Q

What is this?

A

Normal duodenum

45
Q

What is going on here?

A
  • Intestinal TB: foamy macros and PAS-positive organism -> similar appearance to Whipple’s
    1. Acid-fast stain can be helpful bc mycobacteria stain (+), but T. whippelii do not
  • NOTE: mycobacterium avium complex (MAC) consists of two species -> M. avium and M. intracellulare
46
Q

Which of the following is only absorbed in the terminal ileum?

A. Calcium

B. B12

C. Bile salts

D. Iron

A

B. B12 and C. Bile salts

47
Q

Which of the following is the best test to screen for celiac sprue?

A. Lactose hydrogen breath test

B. SBFT: a fluoroscopic technique designed to obtain high resolution images of the small bowel

C. Tissue Transglutaminase IgA

D. MRCP

A

C. Tissue Transglutaminase IgA (if +, then small bowel biopsy)

48
Q

Which of the following does NOT predispose to SBBO?

A. Diabetes

B. Pulmonary HTN

C. Scleroderma

D. Prior bowel surgeries

A

B. Pulmonary HTN

  • NOTE: diarrhea may be fairly common in diabetes due to meds (Metformin), overgrowth, etc.
49
Q

What is tropical sprue (at a very basic level)?

A
  • Like Celiac disease, but presents with patient who spent more than a few months in the tropics
  • May develop several years later