DSA 4: Diarrhea Flashcards

1
Q

how is diarrhea (acute or chronic) clinically described?

A
  • 3 or more loose or watery stools/day
  • decrease in consistency and increase in frequency of BM of individual
  • loss of bicarbonate and potassium
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2
Q

what is considered NON-inflammatory acute diarrhea?

A

less than 2 weeks duration

  • watery, non-bloody
  • usually mild/self-limited
  • caused by a virus or non-invasive bacteria
  • no workup usually required
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3
Q

what is considered inflammatory acute diarrhea?

A

less than 2 weeks duration

  • blood or pus in stool
  • fever
  • usually cause by invasive or toxin-producing bacteria
  • dx requires routine stool bacterial cultures
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4
Q

what is the main cause of acute diarrhea?

A

viral gastroenteritis

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5
Q

what is the most common/likely cause of non-infectious diarrhea?

A

medications
- frequently antibiotics, NSAID’s, Mg laxatives

also caused by food sweeteners (sorbitol) -> said twice that gum contains sorbitol

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6
Q

diarrhea that occurs during the period of antibiotic exposure

  • most cases not attributable to C. diff (must differentiate from antibiotic assoc COLITIS)
  • dose related
  • resolves spontaneously after discontinuation of the antibiotic
  • no specific labs or tx
A

antibiotic-associated diarrhea

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7
Q

what is considered chronic diarrhea?

A

> 4 weeks

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8
Q

what are the 3 most common causes of chronic diarrhea?

A
  • meds
  • IBS
  • lactase deficiency/lactose intolerance
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9
Q

what symptoms are inconsistent with the most common causes of chronic diarrhea and warrant further workup?

KNOW!

A
  • nocturnal diarrhea
  • weight loss
  • anemia
  • positive results on fecal occult blood test (FOBT)
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10
Q

what is stool osmotic gap? what is the normal value?

A

the difference between MEASURED osmolality of the stool (serum) and the ESTIMATED stool osmolality
- normal value is less than 50 mOsm/Kg

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11
Q

what are the clues of osmotic diarrhea?

A
  • stool volume decreases with fasting
  • increased stool osmotic gap (greater than 50-75 mOsm/Kg)

sx: abdominal distention, bloating, flatulence
- due to increased colonic gas production

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12
Q

what should pt’s be asked if you suspect osmotic diarrhea?

A

about their intake of dairy products (lactose), fruits and artificial sweeteners (fructose and sorbitol), and alcohol

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13
Q

what are the most common causes of osmotic diarrhea?

A
  • meds (antacids, lactulose, sorbitol)
  • disaccharide deficiency/carbohydrate malabsorption (lactose intolerance)
  • laxative abuse (Mg!)
  • malabsorption syndromes
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14
Q

stool volume does NOT improve with fasting

  • NORMAL stool osmotic gap
  • increased intestinal secretion
  • **high volume watery diarrhea (>1L/day)
  • may develop dehydration and electrolyte imbalance
A

secretory diarrhea

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15
Q

what are the main causes of secretory diarrhea?

A
  • endocrine tumors (ZES, Carcinoid synd, thyroid carcinoma)
  • bile salt malabsorption (Crohn ileitis, ileal resection)
  • factitious diarrhea (laxative abuse)
  • villous adenoma
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16
Q

what is the initial diagnostic workup of chronic diarrhea?

A
  • CBC
  • serum electrolytes (to calculate osmotic gap)
  • liver enzymes
  • albumin
  • vit A/D
  • TSH
  • IgA tissue transglutaminase (tTG) -> tests for celiac dz
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17
Q

what initial workup should be added if you suspect Giardia or E. histolytica?

A
  • fecal antigen

- wet mounts

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18
Q

What initial workup should be added if you suspect Cryptosporidium and cyclospora?

A

modified acid-fast staining

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19
Q

most pt with chronic persistent diarrhea should undergo colonoscopy with mucosal biopsy to exclude what?

A
  • IBD (Crohn or UC)
  • microscopic colitis
  • colonic neoplasia
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20
Q

when is an upper endoscopy with small bowel biopsy performed?

A
  • when a small intestinal malabsorptive disorder is suspected (celiac, Whipple dz)
  • AIDS pt to document Cryptosoridium, Microsporida and M avum-intracellulare infection
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21
Q

what further studies are added if malabsorption is suspected?

A
  • pancreatic insufficiency (fecal elastase <100mcg/g)
  • chronic pancreatitis (calcification on a plain abdominal radiograph)
  • breath tests (glucose or laculose) for small bowel bacterial overgrowth
  • hydrogen breath test for carbohydrate metabolism
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22
Q

what further studies are added if neuroendocrine tumors suspected?

A
  • vasoactive intestinal peptide (VIPoma)
  • calcitonin (medullary thyroid carcinoma)
  • gastrin (ZES)
  • urinary 5-hydroxyindoleacetic acid (5-HIAA) carcinoid tumor
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23
Q

what medications are common causes of chronic diarrhea?

A
  • cholinesterase inhibitors
  • SSRI’s
  • Ang-11 receptor blockers
  • NSAIDs
  • metformin
  • allopurinol
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24
Q

common GI dz in clinical practice

  • visceral hyperalgesia (increased sensitivity to pain)
  • altered colonic and small-intestinal motility
  • enhanced visceral sensation (lower pain threshold in response to gut distention)
  • increased frequency of pt presenting with psychological disturbance
A

IBS

25
Q

what are the alarm symptoms that are incompatible with dx of IBS and warrant investigation for underlying disease? (7)

A
  • acute onset of symptoms (esp if >40-50 years old)
  • noctunal diarrhea
  • severe constipation
  • hematochezia
  • weight loss
  • fever
  • family hx of cancer, IBD, or celiac
26
Q

female-male ratio 2:1

  • abdominal pain (crampy/lower abd) and irregular bowel habits
  • abdominal distention
  • relief of abd pain with bowel mvmnt
  • increased frequency of stools with pain
  • loose stools with pain
  • mucus in stools
  • sense of incomplete evacuation
A

IBS

chronic > 6 months (but symptoms for a least 3 months before it can considered in differential)
- is a diagnosis of exclusion

27
Q

what diagnostic criteria should be used for IBS?

A

Rome IV clinical diagnosis criteria:

  • recurrent abdominal pain, at least 1 day/week in the last 3 months, assoc with 2+ of the following:
  • related to (either improves or worsens) with defecation
  • change in frequency of stool
  • change in form (appearance) of stool
28
Q

what is the tx of IBS?

A

meds directed towards diarrhea, constipation, and pain

  • dietary intolerances: FODMAPS (reducing these may improve symptoms)
  • fermentable oligosaccharides
  • disaccharides
  • monosaccharides
  • polyols
29
Q

diarrhea, bloating, flatulence, abdominal pain after ingestion of milk-containing products
- dx confirmed by hydrogen breath test

A

lactase deficiency

- lactase is brush border enzyme that hydrolyzes disaccharide lactose into glucose and galactose

30
Q

what is the tx of lactase deficiency?

A

goal of tx is patient comfort
- lactase enzyme replacement available OTC

NOTE: pt who restrict or eliminate milk products may have increased risk of osteoporosis -> Ca supplementation is recommended for susceptible pts

31
Q

what can cause a temporary lactase deficiency?

A

viral enteritis

32
Q

what are the most likely protozoans to cause chronic infections?

A

Giardia, E. histolytica, Cyclospora

33
Q

what intestinal nematode is most likely to cause chronic infection?

A

Strongyloidiases stercoralis

34
Q

what bacteria most likely to cause chronic infection?

A

C. diff

35
Q

what pathogens most likely to cause chronic infection in immunocomprimised/AIDS pts?

A
  • viral: CMV, HIV
  • bacterial: C. diff, mycobacterium avium complex (MAC)
  • protozoal: microsporidia, cryptosoridium, isospora belli, cyclospora
36
Q

what is the most common cause of Antibiotic-Associated Colitis?

A

C. diff

  • gram positive, spore-forming bacillus
  • cytotoxin A and B production (exotoxin mediated)
  • nosocomial transmission (higher risk if hospitalized more than 3 days, or receiving multiple/prolonged abx, or if on PPI)
37
Q

women > men, 50-60’s, idiopathic condition

  • chronic, intermittent watery diarrhea
  • normal-appearing mucosa at endoscopy
  • histo evaluation reveals chronic inflammation
A

lymphocytic colitis and collagenous colitis (2 kinds, very similar)

tx: antidiarrheal therapy: loperamide is first-line
- stop offending agent (diarrhea usually abates within 30 days of stopping med)

38
Q

what medications have been implicated as etiologic agents of colitis?

A
  • NSAIDs
  • PPIs
  • low-dose aspirin
  • selective serotonin re-uptake inhibitors
  • ACE inhibitors
  • beta-blockers
39
Q

disruption of digestion and nutrient absorption

  • weight loss
  • osmotic diarrhea
  • steatorrhea (fecal fat >10g/24hr)
  • nutritional deficiency
A

malabsoprtion syndromes

40
Q

what are the signs of malabsorption?

A
  • loss of muscle mass or subQ fat
  • pallor d/t anemia
  • easily bruising d/t VitK def
  • hyperkeratosis d/t VitA def
  • bone pain d/t osteomalacia (VitD?)
  • neurologic signs (peripheral neuropathy, ataxia) d/t VitB12 or VitE def
41
Q

the following are examples of what kind of malabsorption syndrome?

  • celiac sprue
  • lactase def
  • whipple disease
  • small bowel resections (short bowel syndrome, bile salt malabsorption)
A

small bowel mucosal disorders

42
Q

the following are examples of what kind of malabsorption syndrome?

  • chronic pancreatitis
  • cystic fibrosis
  • pancreatic carcinoma
A

pancreatic disease/insufficiency

43
Q

the following are examples of what kind of malabsorption syndrome?

  • lymphoma
  • carcinoid
  • Tb
  • kaposi sarcoma
A

lymphatic obstruction

44
Q

immunologic response to storage protein gluten (wheat, rye, barley)

  • diffuse damage to the proximal small intestinal mucosa with malabsoprtion of nutrients
  • only develops in people with the HLA-DQ2 (95%) or HLA-DQ8 (5%) class II molecules
  • weight loss
  • chronic diarrhea
  • dyspepsia
  • flatulence
  • abdominal distention
  • growth retardation
  • fatigue
A

Celiac disease (aka sprue, celiac sprue, and gluten enteropathy)

45
Q

what does small intestine of celiac disease look like via endoscopy and histologically?

A
  • smooth appearance on endoscopy (loses it’s lumps/bumps)

- villous atrophy on histo slides (loses normal villi structure)

46
Q

what does destruction of mucosal enterocytes as well as humoral immune response lead to?

A

antibodies to gluten, tissue transglutaminase (tTG) and other autoantigens

47
Q

what are the extraintestinal symptoms found in people with celiac disease?

A
  • fatigue
  • depression
  • iron deficiency anemia
  • osteoporosis
  • short stature
  • delayed puberty
  • amenorrhea
  • reduced fertility
  • dermatitis herpetiformis (pruritic papulovesicles over the extensor surfaces of the extremities, trunk, scalp and neck)
48
Q

what is the dx and tx of celiac?

A
  • dx: IgA tissue transflutaminase (IgA tTg)
  • also check IgG antibodies to anti-DGP, some ppl already have IgA def
  • CBC (for anemia)
  • dual-energy Xray densitometry scanning (to screen for osteoporosis)
  • tx: lifelong removal of all gluten from the diet!

NOTE: celiac disease may be assoc with other autoimmune disorders

49
Q

significant steatorrhea d/t malabsorption of triglycerides, resulting in:

  • weight loss
  • gaseous distention and flatulence
  • large, greasy, foul-smelling stools
A

pancreatic insufficiency

NOTE: micellar function and intestinal absorption are normal, so signs of nutrient or vitamin deficiencies are rare
- protein and carb absorption rarely affected

50
Q

insufficient intraluminal bile salts

  • mild steatorrhea (d/t malabsorption of fatty acids and monoglycerides)
  • minimal weight loss
  • impaired absorption of fat-soluble vitamins results in bleeding tendencies, osteoporosis, and hypocalcemia
  • watery secretory diarrhea
A

bile salt malabsoprtion

51
Q

rare multi-system disease

  • gram positive bacillus, not acid fast (Tropheryma whipplei)
  • fever
  • weight loss
  • malabsorption
  • chronic diarrhea
  • hypoalbuminemia and edema
A

Whipple disease

52
Q

what is the dx, tx and prognosis of Whipple disease?

A
  • dx: endoscopy with duodenal biopsy, periodic acid schiff (PAS)-positive macrophages with characteristic bacillus
  • tx: antibiotic therapy drugs that cross BBB
  • disease is FATAL is left untreated
53
Q

what are examples of antibiotics that cross the BBB?

A

ceftriaxone, meropenem, trimethoprim-sulfamethoxazole

54
Q

frequent passage of small volumes of stool, often associated with

  • rectal urgency, tenesmus (inclination to empty bowels), or a feeling of incomplete evacuation
  • accompanies IBS or proctitis
A

pseudo-diarrhea

55
Q

involuntary discharge of rectal contents

  • caused by neuromuscular disorders or structural anorectal problems
  • diarrhea and urgency, especially if severe, may aggravate or cause incontinence
A

fecal incontinence

56
Q

elderly/nursing home patients

  • fecal impaction that is readily detectable by rectal examination
  • severe constipation -> only contents that get by is liquid
A

overflow diarrhea

NOTE: prolonged impaction can lead to an ulcer!

57
Q
  • pt on opioids, psychiatric dz, prolonged bed rest, neurogenic disorders of the colon, or spinal cord disorders
  • decreased appetite
  • nausea and vomiting, abdominal pain
  • paradoxical diarrhea -> overflow incontinence
A

fecal impaction

tx: relieving the impaction with enema or DRE

58
Q

what are the ONLY three contraindications for a DRE?

A
  • you don’t have a finger
  • the patient doesn’t have a rectum
  • pt has leukopenia (low WBC, could cause dangerous infection)
59
Q

chronic use of laxative can lead to what?

A

melanosis coli (benign hyper-pigmentation of the colon)