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GASTROENTEROLOGY > 2. Diarrhea and Constipation > Flashcards

2. Diarrhea and Constipation Flashcards

1
Q

Main 6 GI Functions

A
  1. Motility - movement of food and liquid by peristalsis
  2. Secretion - exocrine and endocrine hormone secretions
  3. Digestion - mechanical breakdown of food into smaller units
  4. Absorption - passage of digested end products into blood or lymph
  5. Immune Barrier - intestinal mucosal barrier, Gut Associated Lymph Tissue (GALT)
  6. Storage and Elimination - temporary storage and elimination of indigestible products
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2
Q

Nutrient Absorption

A
  • Small Bowel - where most macronutrient digestion and the absorption of carbohydrates, proteins, fats, vitamins and minerals occurs
  • Colon - largely absorbs water and electrolytes. Also extracts nutrients through bacterial fermentation to short-chain fatty acids
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3
Q

Normal Intestinal Fluid Absorption (Amount)

A
  • 9-10 L of fluid enters the jejunum daily
    • Small bowel absorbs 90% of this –>
  • 800-1000 ml of fluid enters the colon daily
    • Colon absorbs 90% of this –>
  • 80-100 ml is excreted each day in feces

If more fluid passes the ileocecal valve, colon can absorb up to 3-4 L

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4
Q

Normal Intestinal Fluid Absorption (Osmolality)

A
  • At baseline, absorption in the intestine is isotonic
    • because the osmolality of intestinal fluid is always the same as plasma
  • Net osmosis occurs due to a concentration gradient established by active transport of solutes into mucosal cells
    • Water follows
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5
Q

Define Diarrhea

A

OBJECTIVELY:

Diarrhea - stool frequency of 3+ BMs/day or stool weight of > 200 g/day

SUBJECTIVELY:

  • Urgency
  • Increased Stool Frequency
  • Loose Stools
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6
Q

Classify Diarrhea

by Length of Time

A
  • ACUTE - up to 2 weeks
  • PERSISTENT - > 2 weeks - 4 weeks
  • CHRONIC - > 4 weeks
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7
Q

Discuss the Bristol Stool Chart

A

Describes defecation on a spectrum from constipation - diarrhea

  • 1 - nuts that are hard to pass
  • 2 - lumpy sausage
  • 3 - cracked sausage
  • 4 - smooth sausage
  • 5 - soft blobs with clear edges
  • 6 - mushy stool
  • 7 - watery stool
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8
Q

Pathophysiology of Diarrhea

A

1-2% decrease in intestinal water absorption results in average fecal water excretion of 100 ml (enough to increase stool weight above 200 g)

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9
Q

Diarrhea Mechanisms

A

Think: He “CRIIAD and got diarrhea”

  • Circulating secretagogues
    • Neuroendocrine tumors
  • Reduction of mucosal surface area (malabsorption)
    • Mucosal disease, resection
  • Infection
    • C. difficile, C. jejuni, E. coli, V. cholera
  • Inflammation
    • IBD, microscopic colitis, vasculitis
  • Absence of ion-transport mechanism
    • Congenital electrolyte malabsorption
  • Disordered regulation (altered motility)
    • Postvagotomy, hyperthroidism, diabetic neuropathy
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10
Q

Difference between Secretory and Osmotic Diarrhea

A

SECRETORY DIARRHEA:

  • Electrolytes account for most of the luminal osmolality
  • Can occur day and night
  • Continues with fasting because issue is with absorption of ions, not dietary intake

OSMOTIC DIARRHEA:

  • Due to unabsorbable solute
  • Stops with fasting because issue is with dietary intake
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11
Q

Fecal Osmotic Gap Purpose, Calculation, Interpretation

A
  • Definition:
    • Fecal Osmotic Gap - used to differentiate between secretory and osmotic diarrhea
  • Calculation:
    • Stool Osmotic Gap = 290 mosm/kg - 2 (stool Na + stool K)
  • Interpretation:
    • ​Secretory = < 50
    • Intermediate = 50-125
    • Osmotic = > 125
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12
Q

Approach to Diarrhea

A

1. Diarrhea, Fecal Incontinence, or Impaction?​

  • Incontinence - involuntary release of rectal contents
    • ​Do a DRE to check sphincter tone
  • Impaction - inability to expel large fecal mass through the anus. Overflow diarrhea can happen when liquid stool passes around the impaction
    • Major risk factor is chronic constipation, so ask about this

2. Rule out Drug-Induced Diarrhea

  • Ask if on:
    • Vasoconstricting Agents - decrease mesenteric blood flow
    • Caffeine - affects activation of transporters/receptors
    • Antacids/Laxatives - cause osmotic diarrhea
    • Antiarrhythmics - cause secretory diarrhea
    • Antibiotics - alter colonic flora, cause secretory diarrhea
    • NSAIDs - cause intestinal irritation, cause secretory diarrhea
  • Establish a temporal relationship between starting the drug and the onset of diarrhea

3. Distinguish acute from chronic diarrhea.

4. Categorize diarrhea as inflammatory, fatty, or watery.

  • Inflammatory –> Colonic evaluation
  • Fatty –> Mucosal - inadequate mucosal transport due to celiac’s or mesenteric ischemia –> Endoscopy with biopsy
  • Fatty –> Luminal - inadequate breakdown of triglycerides due to pancreatic insufficiency –> CT or EUS or SIBO –> breath tests or aspirates
  • Watery –> Secretory or Osmotic –> Consider small bowel and colonic evaluation

5. Consider factitious diarrhea

  • In patients who remain undiagnosed after thorough evaluation
  • Usually surreptitious laxative ingestion
  • Could see Melanosis coli - brownish discoloration of colonic mucosa due to laxatives like senna, cascara, and rhubarb but can be from other conditions
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13
Q

ACUTE DIARRHEA:

History

A
  • PMH:
    • Age –> Institutionalized (drugs)?
    • Diseases –> Diabetes, AIDs
    • Medications
    • Travel –> Common exposure or direct transmission?
    • Infection
  • Onset
  • Characteristics:
    • Frequency
    • Blood
    • Mucus
    • Oil Droplets and Food Particles
    • Watery
    • Diarrhea during day and night (secretory) or just the day?
  • Relievers: Fasting?
  • Treatments
  • Symptoms: Abdominal Pain, Bloating, Cramping, Flatuence, Fever, Weight Loss
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14
Q

Mild vs. Severe Acute Diarrhea

A

MILD

  • 7 days or less
  • No signs of dehydration
  • No signs of toxicity, fever, bleeding
  • Supportive care ok. No workup is generally needed

SEVERE

  • Long duration, elderly patient, or immunocompromised patient
  • Signs of dehydration
  • Patient is toxic-appearing, febrile, or complains of bloody diarrhea
  • Supportive care + Workup
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15
Q

ACUTE NON-INFLAMMATORY AND INFLAMMATORY INFECTIOUS DIARRHEA:

Etiology

Clinical Presentation

Workup

A

ACUTE NON-INFLAMMATORY INFECTIOUS DIARRHEA:

ETIOLOGY:

Typically

  • Viruses
  • Non-invasive Bacteria

Some parasites can cause this type of diarrhea

CLINICAL PRESENTATION:

  • Watery, Non-Bloody Diarrhea
  • Nausea +/- Emesis
  • +/- Abdominal Cramping and Bloating

WORKUP:

Generally not needed as illness is self-limited

ACUTE INFLAMMATORY INFECTIOUS DIARRHEA:

ETIOLOGY:

  • Invasive bacteria
  • Parasites

CLINICAL PRESENTATION:

  • Fever
  • Frequent, small-volume bloody stools
  • Abdominal Cramping
  • Urgency
  • Tenesmus

WORKUP:

  • Stool Studies
  • Inflammatory Markers (ESR, CRP)
  • Fecal Leukocytes
  • Fecal Calprotectin
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16
Q

ACUTE NON-INFLAMMATORY INFECTIOUS DIARRHEA:

Differential

A

VIRAL:

  • Norovirus
  • Rotavirus

BACTERIAL:

  • Vibrio cholerae
  • Enterotoxigenic E. coli
  • Clostridium perfringens
  • Staph aureus

PARASITIC (PROTOZOAL):

  • Giardia Lamblia
  • Cryptosporidium
  • Cyclospora
17
Q

NOROVIRUS:

BUZZ WORDS

History

Transmission

Incubation

Duration

Diagnosis

Management

A

BUZZ WORDS:

Most common cause of epidemic gastroenteritis worldwide

HISTORY:

  • Cruise ships
  • Restaurants/Catered Events
  • Schools
  • Military Bases
  • Prisons

TRANSMISSION:

  • Fecal-oral (shellfish, salads, sandwiches, frosting, produce)

INCUBATION:

1-2 days

DURATION:

12-60 hours

DIAGNOSIS:

Clinical. RT-PCR amplification rarely performed

MANAGEMENT:

  • Fluids
  • Electrolyte Repletion
  • Time
18
Q

ROTAVIRUS:

BUZZ WORDS

History

Transmission

Incubation

Diagnosis

Management

Prophylaxis

A

BUZZ WORDS:

  • Most common cause of severe gastroenteritis IN CHILDREN worldwide

HISTORY:

  • Children 6 months-2 years
  • Healthcare Workers
  • Nosocomial Exposure
  • Immunocompromised / Long-Term Care Facility Residents

TRANSMISSION:

Fecal-oral

INCUBATION:

< 48 hours

DIAGNOSIS:

  • Clinical
  • Labs may show signs of dehydration (metabolic acidosis, electrolyte abnormalities, elevated BUN/Cr)
  • ELISA or PCR amplication of viral shedding in stool after 1-4 days of illness

MANAGMENT:

  • Fluids
  • Electrolyte Repletion
  • Time

PROPHYLAXIS:

  • RotaTeq (3 doses total given at 2, 4, and 6 months)
  • Rotarix (2 doses total given at 2 and 4 months)
19
Q

VIBRIO CHOLERAE:

BUZZ WORDS

History

Transmission

Main Symptom

Diagnosis

Management

A

BUZZ WORDS:

Rice water stools

HISTORY:

Overcrowding (natural disasters, refugee camps)

TRANSMISSION:

Fecal contamination of water, fish, undercooked grains, and produce

MAIN SYMPTOM:

MASSIVE, watery diarrhea (rice water stool)

DIAGNOSIS:

  • Stool culture is GOLD STANDARD
  • WHO clinical definition when laboratory testing not possible
    • No Cholera Outbreak: Any patient 2+ presenting with acute watery diarrhea and severe dehydration / dying from acute water diarrhea.
    • Cholera Outrbreak: Any person presenting with acute watery diarrhea / dying from acute watery diarrhea.

MANAGEMENT:

HYDRATION!

20
Q

ENTEROTOXIGENIC E. COLI:

BUZZ WORDS

History

Transmission

Incubation

Management

A

BUZZ WORDS:

Leading cause of Traveler’s Diarrhea

HISTORY:

Travel to resource-limited regions of the world

TRANSMISSION:

Fecal oral contamination of food or water

INCUBATION:

1-3 days

MANAGEMENT:

  • Fluid
  • Electrolytes
  • Nutritional Support
21
Q

FOOD POISONING:

Symptoms

Etiology

A

SYMPTOMS:

  • Fever
  • Nausea +/- Vomiting
  • Abdominal Cramping
  • Diarrhea

ETIOLOGY:

  • Bacillus Cereus
  • Clostridium Perfringens
  • Staph Aureus

GASTROENTEROLOGY (3 decks)

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