Week 9: Gastrointestinal - Dyspepsia, Nausea, Diarrhea, Constipation Flashcards

1
Q

Definition of constipation

A

Defecation <3 times per week; often with straining and passage of hard, uncomfortable stool
Frequency or consistency outside normal for patient

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2
Q

Symptoms of constipation

A
  • Decreased frequency of bowel motion
  • Change nature of stool
  • Straining
  • Incomplete sense of evacuation
  • Bloated
  • Cramp/discomfort
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3
Q

Causes of constipation

A

Lifestyle

  • Inadequate fluid intake
  • Low fibre diet
  • Lack exercise

Other causes

  • Some medications
  • Conditions including MS, Parkinson’s, diabetes, depression and hypothyroidism
  • Obstruction of bowel
  • Pregnancy
  • Advancing age
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4
Q

Complications of constipation

A
  • Anorexia and nausea often experienced with constipation
  • Continued fluid absorption from bowel lead to fecal impaction leading to overflow diarrhea or bowel obstruction
  • Hemorrhoids and anal fissures from straining
  • Fecal impaction can lead to urinary retention and overflow incontinence
  • Elderly can also experience confusion and delirium
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5
Q

Non pharmacological interventions for constipation

A

The four F’s

  • Fibre = increase gradually to avoid bloating and flatulence (adequate fluid)
  • Fluid
  • Fitness
  • Feet - positioning on toilet
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6
Q

Treatment of constipation

  • When to use laxative
  • Factors influencing laxative choice
A

Use laxative if

  • Lifestyle and dietary changes are ineffective
  • Fecal impaction develops
  • Taking or starting opioid analgesic

Factors affecting laxative choice

  • Symptoms
  • Rate of onset
  • Age
  • Preference of patient
  • Adverse effects
  • Effectiveness of previous treatment
  • Cost
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7
Q

Bulk forming laxatives

  • MOA
  • Examples
  • Indication
  • Practice point
A

MOA
- Increase volume of intestinal contents, stimulating peristalsis or intestinal motility

Examples
- Psyllium

Indications
- Mild constipation - can take 3 days to see full effect

Practice points

  • Adequate hydration is required
  • Gradual increase in fibre will decrease likelihood of adverse effects such as bloating, impaction, flatulence
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8
Q

Osmotic laxatives

  • MOA
  • Examples
  • Indication
  • Practice points
A

MOA
- Draw fluid into feces or retain fluid in colon by osmotic effect to increase volume of stool therefore stimulating peristalsis

Examples

  • Lactulose
  • Glycerine
  • Macrogol
  • Sorbitol, saline

Indications

  • Lactulose can take 2-3 days to work (chronic constipation)
  • Low dose of mactrogol useful in chronic constipation
  • Glycerine suppositories and large doses of macrogol can be used hen rapid relief is required (within 2 hrs effect)

Practice points

  • Take with fluid to augment osmotic effect
  • Affect fluid balance in body so be careful in CVD patients
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9
Q

Stimulant laxatives

  • MOA
  • Examples
  • Indications
  • Practice points
A

MOA

  • Direct stimulation of nerve endings in colonic mucosa, which increases intestinal motility
  • Cause accumulation of water and electrolytes in colon

Examples

  • Bisacodyl
  • Senna

Indications
- Reserved or opioid induced constipation or severe constipation unresponsive to bulking or osmotic laxatives

Practice points

  • Take effect within 6-12 hrs
  • Should not be used long term as it can be difficult to establish normal bowel movements one ceased (rebound constipation)
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10
Q

Stool softening laxatives

  • MOA
  • Examples
  • Indications
  • Practice points
A

MOA
- ease passage via assisting absorption of water into stool

Examples

  • Docusate
  • Liquid paraffin (children)

Indications
- Usually in combination with another laxative (stimulant)

Practice points

  • No evidence that use alone are effective laxatives
  • Onset of action is 1-3 days
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11
Q

Suppositories and Enemas

  • MOA
  • Indications
  • Examples
A

MOA

  • Used locally when rapid effect is required or patient cannot take medication orally
  • Inserted rectally
  • Suppositories are semi-solid (melt when hit warmth of rectum)
  • Enemas are liquid based

Indications
- Treat fecal impaction

Examples

  • Glycerine suppositories
  • Osmotic enemas
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12
Q

Laxative - special populations (pregnancy)

A
  • Avoid stimulant laxatives
  • Suggest management advice (4 f’s)
  • If have to use laxative suggest bulk forming or stool softener
  • Docusate, lactulose or sorbitol are category A
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13
Q

Laxatives - special populations (elderly)

A

Following factors can contribute to development of constipation

  • Changed environment
  • Decrease mobility
  • Drugs
  • Diminished intake of fiber and fluid
  • Painful anorectal disorders
  • Co-morbidities which cause loss of muscle power

Bulking agents effective if mobile
Osmotic and stimulant useful if bed bound and on opioids

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14
Q

Fecal impaction

  • Definition
  • Presentation
  • Management
A

Definition

  • Contents of colon build up to point where cannot physically pass
  • Presents as fecal incontinence or overflow diarrhea

Management

  • High dose oral macrogol
  • Suppositories and enemas
  • Manual disimpaction
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15
Q

Prevention and treatment of opioid induced constipation

A
  • Constipating effect is mediated through mu receptor in GIT
    > Peristalsis is decreased, pancreatic and biliary secretions are decreased (necessary for proper stool formation and passing)
  • Constipating effect is dose related and tolerance rarely develops

Agents of choice
- Stool softener + stimulant or osmotic laxative

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16
Q

Definition of diarrhea

Classification of diarrhea

A

Definition
- Increase in fecal discharge, in terms of volume, fluid quantity and/or frequency relative to usual bowel habits

Classification

  • Acute (<7 days)
  • Persistent (>14 days)
  • Chronic (>28 days)
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17
Q

Clinical features of diarrhea

A
  • Rapid onset
  • N&V may be present prior to or during acute diarrhea
  • Abdominal cramping and tenderness
  • If due to rotavirus - might experience symptoms of cough and cold
  • Acute infection diarrhea is usually watery with no blood present
  • Complete resolution of symptoms 2-4 days
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18
Q

Causes of acute diarrhea

A
  • Some infectious agents
    > Virus (rotavirus, norovirus)
    > Bacterial (e.coli, campylobacter, vibrio cholerae, salmonella, clostridium difficile)
    > Parasite (Giardia)
  • Contaminated food and water (travelers diarrhea)
  • Drugs
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19
Q

Causes of chronic diarrhea

A
  • Coeliac disease - disorder of small bowel caused by immune response to ingested wheat or wheat related products
  • Irritable bowel syndrome - cause thought to include altered bowel motility, hypersensitivity and psycho social factors
  • Inflammatory bowel disease (ulcerative colitis and Crohn’s disease) - chronic, relapsing condition characterized by chronic inflammation
  • Lactose intolerance - deficiency of lactase in small bowel mucosa resulting in lactose malabsorption
  • Diverticular disease - herniations of colonic mucosa through the muscle layer in large bowel
  • Fecal impaction - constipation with overflow
  • Gastrointestinal cancer - persistent diarrhea
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20
Q

Substances commonly causing diarrhea

A
  • Acarbose and Metformin
  • Alcohol
  • Antibiotics
  • Cytotoxic agents
  • Food and drug addititves (sorbitol, mannitol, fructose)
  • Laxative
  • Magnesium containing antacids
  • NSAIDS
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21
Q

Management of acute diarrhea

  • ORS
  • Short term dietary adjustment
  • Treatment options
A

Most cases are self limiting and do not require drug therapy
- Oral rehydration solutions (ORS) prevent dehydration and correct electrolyte disturbances (IV rehydration may be required in severe cases)
- Short term dietary adjustments
> Limit consumption of fatty, sweet or spicy food
> Increase consumption of starchy food
> Avoid alcohol and caffeine
> Increase probiotics
> Limit fruit juice in children (sugar makes it worse)
> May get lactose intolerance for period of time

Treatment options
- Fluid in adults
- ORS
- OTC anti-motility medicines
> Loperamide
> Diphenoxylate
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22
Q

Symptoms of moderate to severe dehydration (most dangerous complication of diarrhea)

A
  • Weight loss
  • Lethargy
  • Dry lips, eyes, tongue
  • Increase thirst
  • Sunken eyes
  • Sunken fontanelle (babies)
  • Loss of skin rigidity
  • Decrease urine output
  • Rapid pulse
  • Dark urine
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23
Q

Antidiarrheas/Antimotility agents

  • MOA
  • Indications
  • Contraindications
A

MOA
- Slow gut motility and allow more toxins to be absorbed (slow resolution of diarrhea)

Indication
- Short term use for control of symptoms during periods of social inconvenience as just prevents inevitable

Contraindications

  • Patients where possibility of invasive organism
  • Should not be used in children
24
Q

Opioid anti-diarrheas

  • MOA
  • Indications
  • Contraindications
  • Side effects
A

MOA
- Activate opioid receptors in gut wall to reduce bowel motility and increase fluid absorption back into body

Indication
- Short term treatment of acute diarrhea

Contraindications

  • Intestinal obstruction, chronic diarrhea, children
  • Avoid long term use due to potential addictive effect

Side effects

  • Abdominal pain
  • Bloating
  • N&V
  • Constipation
25
Other diarrhea treatment options - Antibiotics - Anti-cholinergics
Antibiotics (metronidazole, tinidazole, norfloxacin) - Severe bacterial/protozoal infections or if there is an outbreak requiring prophylactic therapy Anti-cholinergics (Hyoscine, atropine, hyoscamine) - Slow gut by blocking cholinergic receptors - Doses of OTC products too low to work - Increased dose can have adverse effects due to action in CNS as well as GIT
26
Definition of gastro-oesophageal reflux disease (GORD)
Condition that develops when reflux of stomach contents causes troublesome symptoms and/or complications and significantly effects person's wellbeing - Reflux symptoms > 2 times a week or significant impact of QALY
27
Pathophysiology of GORD
Key factors - Spontaneous or transient or sustained relaxation of lower esophageal sphincter - Low resting pressure of LOS - Increased intra abdominal pressure - Reduced esophageal clearance - Impaired mucosal defences
28
Risk factors of GORD Comorbidities of GORD Factors increasing the likelihood of reflux
Risk factors - Genetic - Demographic (age, gender, pregnant) - Lifestyle (diet, coffee consumption, alcohol, dietary habits, body mass index, physical exercise, smoking) - Environmental (hiatus hernia, stress, medication use) Comorbidities - Abdominal pain/dyspepsia - Dysphagia - Asthma - Chest pain - ENT infection - URT infection - Anxiety/mood disorders - Cough and/or laryngitis Likelihood of reflux increases when - Gastric pressure increases (obesity, pregnancy, tight clothing) - Gastric volume increase after meals - Gastric contents near LOS (laying down or bending over) - Gastric emptying delayed (fatty food)
29
Complications of GORD
Not adequately treated can develop complications from long term acid exposure - Oesophagitis - Oesophageal strictures - Oesophageal cancer
30
GORD lifestyle modifications
- Raise head of bed at night - Smaller more frequent meals - Weight loss - Smoking cessation - Decrease alcohol intake - Avoid bending or stooping after eating - Avoid eating or drinking 2-3 hrs before bed - Decrease intake of fatty food, spicy food or chocolate - Decrease caffeine intake
31
Pharmacological treatment of GORD - Treatment options > MOA > Prefix/suffix (examples)
Antacids - Neutralize hydrochloric acid secreted by gastric parietal cells Alginate-antacids - Form relatively pH neutral barrier to decrease exposure to esophageal to acidic gastric content - Examples (alginic acid, sodium alginate) H2RAs - Competitively block histamine 2 receptor on parietal cells, reducing gastric acid secretion - Examples (-tidine) PPIs - Inactivate the hydrogen/potassium ATPase enzyme system (proton pump) suppressing both stimulated and basal acid secretion - Examples (-prazole)
32
Mild/Moderate GORD 1st line therapy - Antacids | - Practice points
Antacids - Short term relief of symptoms (fast onset and short duration) - Take between meals or at bed when expect symptoms to occur - Optimal effect 1-3 hrs after meals - Tablet should be chewed or sucked before swallowing and take with glass of water - May need 2nd line if required more that twice a week
33
GODR - H2 receptor antagonists (H2RAs) | - Practice points
- Onset about 30-45 min - Duration about 10 min - Some available OTC - Generally well tolerated
34
GORD - Proton pump inhibitors (PPI) - Practice points - Drug interactions with PPIs
- Most effective if taken 30-60 min before food - Onset 1 hr but can take 2-3 days to see full effect - Duration 12 hrs - Take for 4 weeks then review Drug interactions - Clinically important interactions are rare - All acid suppressing drugs potentially decrease absorption of some drugs by increasing gastric pH > separate by 2 hrs - PPI mainly metabolized by CYP2C19 and CYP3A4 enzymes
35
GORD maintenance therapy
Aim - Control symptoms - Reduce risk of complications - Minimize cost
36
Peptic ulcer disease (PUD) - Definition - Common forms - Types of ulcers
Definition - Breakthrough entire thickness of gastric or duodenal mucosa as result of acid and pepsin in gastric juice Common forms - Associated with H. Pylori - Associated with aspirin and NSAIDS Types of ulcers - Duodenal - Gastric
37
Causes of PUD
- H. pylori - NSAID use - Smoking - Chronic alcohol consumption - Chemotherapy and radiotherapy - Stress related mucosal damage
38
Clinical presentation of PUD
- Mild pain (burning, gnawing or aching) - Abdominal pain (burning or feeling discomfort) - Nocturnal pain - Severity of pain fluctuates - Pain often occurs 1-3 hrs after meal - Patients may complain of heartburn, belching, bloating, nausea or vomiting - Bleeding indicated by coffee ground vomit or black, tarry stools
39
Complications of PUD
- Mild to severe hemorrhage (hematemesis, weakness, fainting, blood in stool, thirst and sweating) - Stomach or duodenal wall perforation (causes intense, persistent abdominal pain) - Gastric outlets obstruction (caused by scarring, spasm or inflammation from ulcer)
40
Goals of therapy in PUD
- Eradicate H. pylori - Resolve symptoms - Reduce acid secretion - Promote epithelial healing - Prevent ulcer related complications - Prevent ulcer recurrance
41
Lifestyle modifications of PUD
- Avoid exposure to factors known to worsen disease and exacerbate symptoms - Reduce psychological stress - Avoid smoking - Avoid alcohol consumption - Avoid food or beverages that exacerbate ulcer symptoms (spicy, fatty, acidic) - Avoid NSAIDS or aspirin use
42
Eradication of H.pylori
1st line - Esomeprazole (PPI) + clarithromycin + amoxicillin with triple therapy having 85-90% success rate as H.pylori is resistant to either on own
43
NSAID related PUD
- Most are gastric - Stop NSAID if possible and use PPI for 4-8 weeks - Several factors increase risk of developing GI complications > Age > History of PUD or ulcer bleeding > High NSAID dosage > Prolonged use > Concomitant drug therapy
44
Low dose aspirin and PUD
- Increase risk of PUD with low dose aspirin | - Effect is dose dependent and not reduced by enteric coated or buffered aspirin
45
Pathophysiology of nausea and vomiting
See diagram - Nausea and vomiting caused by stimulation of salvation and respiratory centers, pharyngeal, GI and abdominal muscle contraction which is stimulated by the central vomiting center in medulla. - The Central vomiting center is stimulated by chemoreceptor trigger zone, vestibular system, cerebral cortex and gastrointestinal visceral afferents
46
Causes of acute N&V
- Medications/toxins - Physical stress - Emotional stress - Motion/vestibular activity - Most common cause is viral gastrointestinal and bacterial food poisoning - Mechanical GI obstruction - Pregnancy - Neurological
47
Causes of chronic N&V
- Drugs - GI conditions - General medical conditions - Neurological conditions - Psychiatric/psychological
48
What drugs cause N&V
- Chemotherapy - Opiates - NSAIDS - Digoxin - Antiarrhythmia - T2DM - Antibiotics - Nicotine - Anticonvulsants - High dose vitamins
49
Non pharmacological treatment for N&V
- Gradually drink larger amounts of clear liquids - Avoid solid food - Eat light, bland food - Avoid fried, greasy or sweet food - Eat slower and smaller, more frequent meals - Do not mix hot and cold foods - Drink beverages slowly - Avoid activity after eating - Rest - Temporarily discontinue oral medication if they irritate stomach if it is safe
50
Management of N&V
- Identify underlying cause - Ensure adequate hydration ORS - Antiemetic drugs > Dopamine antagonist, sedating antihistamines, anticholinergics, 5HT3 antagonists
51
N&V - Dopamine antagonists - MOA - Examples - Practice point
MOA - Block dopamine receptor in chemoreceptor trigger zone Examples - Domperidone - Metoclopramide - Prochlorperazine Practice points - All except doperidone work elsewhere in CNS and may cause EPSE under 20 yrs - Drowsiness due to CNS activity
52
N&V - Sedating antihistamines - MOA - Examples - Practice points
MOA - Act on H1 and dopamine receptors in CTZ Example - Pheniramine - Promethazine Practice points - Used to prevent motion sickness and other vestibular disorders - Cause sedation - Do not use under 2 yrs
53
N&V - anticholinergics - MOA - Examples - Practice points
MOA - Block muscarinic receptor in vestibular system Examples - Hyoscine Practice points - Used only for motion sickness - Avoid in children <2 yrs - Lots of ADR
54
N&V - 5HT3 antagonist - MOA - Examples - Practice points
MOA - Activation stimulates visceral nerve fibers in GIT and stimulates CTZ, antagonist blocks activation of these receptors Examples - Ondansetron Practice points - Associated with cancer chemotherapy and radiotherapy - Post operative - Used where conventional antiemetics not tolerated - Common for morning sickness
55
N&V complementary therapies that are clinically proven
Ginger - High dose - Recommended for morning sickness - Prevention of travel sickness Vitamin B6 - Preventing and treating morning sickness - Avoid large dose due to peripheral neuropathy