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MBBS 3: Internal Medicine > Diarrhea (DN) > Flashcards

Diarrhea (DN) Flashcards

1
Q

Normal stool contents?

A
  1. 100ml of water
  2. 40mEq/l Na+
  3. 90 mEq/l Cl-
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2
Q

What is diarhhea?

A
  • from 3x week to 3x per day and can be increased secretion >200mls per day
  • stool volume >200-250g/day
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3
Q

Types of diarrhea?

A
  1. osmotic
  2. secretory
  3. inflammatory vs non-inflammatory
  4. acute vs chronic
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4
Q

Describe features of acute diarrhea?

A
  • over 2 - 3 weeks
  • commonly infectious
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5
Q

Describe features of chronic diarrhea?

A
  • > 4 weeks
  • can bedue to a chronic medical condition
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6
Q

Causes of diarrhea?

A
  1. 80% are infectious
    – helminths, bacteria, viruses, protozoa
  2. ingestions of medicines
  3. poor absorption of sugars
  4. fecal impaction
    Note: Diarrhea results from imbalance of intestines to handle water and electrolytes
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7
Q

The 2 types of disease of enteric bacteria?

A
  1. Diarrhea with or without systemic invasion
  2. Other infections including:
    - UTI, pneumonia, bacteremia, and sepsis especially in debilitated patients
    NB: Some of them are normal flora but can acquire antibiotic resistance to cause Nosocomial Sepsis in hospitals
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8
Q

Enteric bacteria?

A
  • group of bacteria that exist in the intestines of humans and animals
  • Enteric bacteria can be either harmless, such as gut flora or microbiota, or pathogenic, which means that they cause disease
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9
Q

Bacterial causes of diarrhea?

A
  1. Salmonella
  2. Campylobacter
  3. Shigella
  4. E. coli 0157:H7
  5. Clostridium difficile
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10
Q

Viral causes of diarrhea?

A
  1. Norovirus and other related viruses
  2. Rotavirus (esp. in children)
  3. Adenovirus
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11
Q

Protozoal causes of diarrhea?

A
  1. Giardia
  2. E. histolytica
  3. Cyclospora
  4. Cryptosporidium
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12
Q

Pathophysiology and features of secretory diarrhea?

A

Increased secretion of water into the gut lumen and inhibition of intestinal absorption
1. Large stool volume >1litre per day
2. Watery stool
3. Absence of pus, blood, mucus
4. Persistent diarrhea despite 24 – 48 hour fast

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13
Q

Pathophysiology of osmotic diarrhea?

A
  • Increased amounts of poorly absorbable, osmotically active solutes into the bowel lumen
  • Typically, diarrhea stops when patient fasts
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14
Q

Causes of osmotic diarrhea?

A
  1. carbohydrate malabsorption
  2. Generalized malabsorption e.g. sprue, after radiation, pancreatic insufficiency
  3. Ingestion of osmotically active substances
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15
Q

Motility disorders causing diarrhea?

A
  1. increased small bowel motility resulting in reduced contact time
  2. Decreased small bowel motility resulting in small bowel bacterial overgrowth
  3. Increased colonic motility such as in Irritable bowel syndrome (IBS)
  4. Anal sphincter dysfunction causing incontinence
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16
Q

Causes of increased small bowel motility?

A
  1. hyperthyroidism
  2. carcinoid
  3. dumping syndrome
    > resulting in reduced contact time
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17
Q

Causes of decreased small bowel motility?

A
  1. hypothyroidism
  2. scleroderma
  3. amyloidosis
    > resulting in small bowel bacterial overgrowth
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18
Q

Causes of anal sphincter dysfunction?

A
  1. after obstetric surgery
  2. inflammation and neuromuscular diseases
    > causing incontinence
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19
Q

Investigation of bloody acute diarrhea?

A
  1. Culture and sensitivity
  2. Sigmoidoscopy may be required
  3. May consider CT scan
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20
Q

Causes of bloody acute diarrhea?

A

CHESS agents
C – Campylobacter
H- Hemorrhagic E. coli 0157:H7
E- Entamoeba histolytica
S- Salmonella
S-Shigella

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21
Q

Features of non-bloody acute diarrhea?

A
  1. Are mostly viral
  2. Remission is spontaneous without additional treatment
  3. Rarely complicate
  4. Investigate if fever, pus, dehydration etc.
22
Q

Features of infectious diarrhea?

A
  1. Fever
  2. Pus
  3. Bloody
  4. Epidemic
  5. Travel
23
Q

Features of non-infectious diarrhea?

A
  1. Afebrile
  2. Non-bloody
  3. Sporadic
  4. No pus
  5. No travel
24
Q

History to take in diarrhea cases?

A
  1. food
  2. nutritional
  3. time before onset of symptoms
  4. Travel history
  5. Exposure of farm animals and farm products e.g. brucellosis and salmonella
  6. Drug history
  7. Eating raw vegetables
  8. Features of immunosuppression including HIV exposure
  9. Pregnant women are at high risk of contracting Listeria monocytogenes
25
Time before onset of symptoms and their associated pathogens?
1. Within 6hrs of ingesting preformed toxin – Staph aureus: dairy products – Bacillus cereus: fried rice 2. 8-16 hours – Clostridium perfringens: reheated meat) 3. >16 hours – viral or bacterial e.g. enterotoxigenic or enterohemorrhagic E.coli
26
Things to note in physical examination?
1. Hydration status 2. Vital signs – BP (include orthostatic hypotension) – PR – Temperature 3. Anemia in bloody diarrhea 4. Abdominal tenderness and any masses
27
Features of viral acute diarrhea?
1. Usually sudden onset 2. No mucosal invasion, watery stool, Self limiting 3. Can cause mild dehydration
28
Features of bacterial acute diarrhea?
1. Sudden onset 2. Self limiting most of the time but others need antibiotics 3. Outbreaks can be severe
29
Pathogens that cause small bowel acute diarrhea?
1. Bacteria - Vibrio cholerae - Enterotoxigenic E.coli 2. Protozoa - Giardia - cryptosporidium - isospora - microsporidia
30
Features of small bowel acute diarrhea?
1. Minimal inflammation 2. watery diarrhea
31
Pathogens that cause large bowel acute diarrhea?
1. Bacteria - Campylobacter (most common), Salmonella (poultry), shigella (day-care centers), Yersinia, invasive E.coli e.g. serotype 0157:H7 & C. difficile (antibiotic related) 2. Parasites – Entamoeba histolytica
32
Features of invasive/inflammatory acute diarrhea?
1. Usually there is inflammation 2. mucosal invasion 3. blood and fecal leucocytes
33
Causes of chronic diarrhea?
1. Infections 2. Inflammation 3. Malabsorption 4. Drugs 5. Endocrine disorders 6. Motility disorders
34
Infectious causes of chronic diarrhea? | Protozoa and Bacteria
Protozoa 1. Giardia 2. E. histolytica 5. Cryptosporidium 6. Microsporidia 7. Isospora (in AIDS patients) Bacteria 8. M.tuberculosis 9. C. difficile
35
Inflammatory causes of chronic diarrhea?
1. Ulcerative colitis 2. Crohn's disease 3. ischemia
36
Drug causes of chronic diarrhea?
1. NSAIDS 2. theophylline 3. antibiotics
37
Malabsorption causes of chronic diarrhea?
1. lactose intolerance 2. pancreatic insufficiency
38
Endocrine causes of chronic diarrhea?
1. Zollinger Elson Syndrome 2. hyperthyroidism 3. carcinoid 4. VIPoma 5. villous adenoma 6. diabetes mellitus
39
Motility disorders that cause chronic diarrhea?
1. IBS 2. dumping syndrome
40
What is dumping syndrome?
interchange between constipation and diarrhea
41
Clinical features of small bowel chronic diarrhea?
1. large volume, watery, greasy stools with occasional food particles 2. intermittent crampy abdominal pain
42
Clinical features of large bowel chronic diarrhea?
1. Small volume stool with possible mucus, blood or pus, tenesmus 2. pelvic or sacral pain relieved by passing stool
43
Investigations?
1. FBC, BUN and creatinine 2. Stool for blood (gross and occult), fecal leucocytes or lactoferrin, fat and trophozoites 3. Stool for culture - Salmonella, Shigella, Campylobacter - stool osmolality - C. difficile toxin assay - acid fast stain (Isospora, Cryptosporidia) 4. Proctosigmoidoscopy/ colonoscopy – esp. for bloody diarrhea and to rule out Inflammatory Bowel Disease 5. Small bowel biopsy if malabsorption is suspected
44
Treatment for diarrhea?
1. Treat underlying cause 2. Correct fluid and electrolytes 3. Rational use of antibiotics – consider fluoroquinolones and Trimethoprim 4. Caution on use of antimotility drugs
45
Characteristic features of salmonella?
1. Oral fecal and can be in outbreaks in schools and institutions 2. Poultry products can harbor 3. 8 to 48 hours incubation 4. can complicate into bowel perforation, abscesses and death
46
What are the 4 disease states in humans that are causes by salmonella?
1. Typhoid fever 2. Carrier state 3. Sepsis 4. Gastroenteritis (diarrhea)
47
Pathophysiology of typhoid fever?
1. Salmonella invades regional LNs before seeding multiple organ systems 2. Bacteria are phagocytosed by monocytes and can survive intracellularly
48
Clinical features of typhoid fever?
1. Fever 2. headache 3. abdominal pain 4. diffuse or localized RUQ pain (over the terminal ileum) mimicking appendicitis 5. Splenomegaly and Rose spots on the abdomen can develop 6. diarrhea
49
How to diagnose typhoid fever?
by culture of blood, urine or stool
50
Treatment of typhoid fever?
1. Ciprofloxacin 2. ceftriaxone
51
Describe the carrier state of salmonella?
1. Salmonella is harbored in the gallbladders of people that have recovered from typhoid 2. The patients are usually asymptomatic 3. May need surgical removal of gall bladders
52
Describe sepsis in salmonella?
1. Salmonella is a capsulated bacteria and the capsule is cleared by opsonization by antibodies, macrophages and neutrophils in the spleen 2. Asplenia increases the risk of Sepsis from Typhoid (Hemophilus influenzae, Streptococcus) – in patients such as those with sickle cell disease or those with surgical removal of the spleen

MBBS 3: Internal Medicine (72 decks)

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