Week 9: Gastrointestinal - Dyspepsia, Nausea, Diarrhea, Constipation Flashcards
Definition of constipation
Defecation <3 times per week; often with straining and passage of hard, uncomfortable stool
Frequency or consistency outside normal for patient
Symptoms of constipation
- Decreased frequency of bowel motion
- Change nature of stool
- Straining
- Incomplete sense of evacuation
- Bloated
- Cramp/discomfort
Causes of constipation
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
Complications of constipation
- 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
Non pharmacological interventions for constipation
The four F’s
- Fibre = increase gradually to avoid bloating and flatulence (adequate fluid)
- Fluid
- Fitness
- Feet - positioning on toilet
Treatment of constipation
- When to use laxative
- Factors influencing laxative choice
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
Bulk forming laxatives
- MOA
- Examples
- Indication
- Practice point
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
Osmotic laxatives
- MOA
- Examples
- Indication
- Practice points
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
Stimulant laxatives
- MOA
- Examples
- Indications
- Practice points
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)
Stool softening laxatives
- MOA
- Examples
- Indications
- Practice points
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
Suppositories and Enemas
- MOA
- Indications
- Examples
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
Laxative - special populations (pregnancy)
- 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
Laxatives - special populations (elderly)
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
Fecal impaction
- Definition
- Presentation
- Management
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
Prevention and treatment of opioid induced constipation
- 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
Definition of diarrhea
Classification of diarrhea
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)
Clinical features of diarrhea
- 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
Causes of acute diarrhea
- Some infectious agents
> Virus (rotavirus, norovirus)
> Bacterial (e.coli, campylobacter, vibrio cholerae, salmonella, clostridium difficile)
> Parasite (Giardia) - Contaminated food and water (travelers diarrhea)
- Drugs
Causes of chronic diarrhea
- 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
Substances commonly causing diarrhea
- Acarbose and Metformin
- Alcohol
- Antibiotics
- Cytotoxic agents
- Food and drug addititves (sorbitol, mannitol, fructose)
- Laxative
- Magnesium containing antacids
- NSAIDS
Management of acute diarrhea
- ORS
- Short term dietary adjustment
- Treatment options
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
Symptoms of moderate to severe dehydration (most dangerous complication of diarrhea)
- 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
