Week 10

• Motility


  Contraction and relaxation of walls and sphincters of gastrointestinal tract to move content
• Gastrointestinal motility


  • Fragments and mixes food boluses for digestion and absorption
  • Propels contents along the tract
• Food bolus


  Ball-like mixture of food and saliva that forms in the mouth during the process of chewing
• Tonic contractions


  Sustained contractions that are maintained for several minutes to hours
• Tonic contractions


  • Usually observed at the sphincters separating the different parts of the gastrointestinal tract
  • Tightly regulated, mostly unconsciously, except for the sphincters that control defecation, which are co-ordinated at the defecation centres in the lumbro-sacral spinal cord with conscious input
• Phasic contractions


  Periods of relaxation and contraction, rather than being sustained
• Phasic contractions


  Result from autonomic signalling overlayed on slow waves that are generated by the interstitial cells of Cajal in the enteric nervous system
• Constipation


  Small/infrequent/difficult bowel movements
• Most people will experience occasional bouts of constipation, due to things such as dehydration or lack of fibre
• Chronic constipation


  Typically involving fewer than three bowel movements a week
• Chronic constipation can have significant impact on quality of life
• Causes of constipation


  • Neurological problems that affect the nerves that control the colon and rectum
  • Diabetes induced nerve damage and certain neurodegenerative disorders, such as multiple sclerosis, Parkinson's and dementia
  • Blockages in the colon or rectum such as bowel obstructions, rectal cancer or other abdominal cancer that puts pressure on the colon
  • Physical problems with the muscles involved in defecation such as defects in coordination of relaxation and contraction or inability to relax pelvic muscles
  • Conditions leading to dehydration such as chronic hyperglycaemia as a result of diabetes and thyroid imbalances
• Interventions that don't involve drug in circulation

  • Stool softeners
  • Osmotics
  • Stimulants
  • Bulk-forming agents
• Opioid-induced constipation


  Opioids commonly cause constipation
• Dealing with opioid-induced constipation

  1. Give laxatives when a patient starts opioid treatment, rather than waiting for constipation to occur

  2. Use an osmotic laxative and/or a stimulant laxative

  3. Do not use bulk-forming laxatives and be cautious if increasing dietary fibre, as these can worsen constipation
• Laxatives can be misused for a variety of reasons, one being for weight loss. This is why pharmacist must help deem if it is appropriate for use
• Acute diarrhoea


  Typically associated with viral or bacterial infections or the effects of a course of antibiotics
• Chronic diarrhoea


  May be the result of a food intolerance or can be a symptom of irritable bowel syndrome or inflammatory bowel disease such as Crohns, Ulcerative Colitis or Coeliac disease
• Chronic diarrhoea


  Having at least one quarter of stools being loose or watery for a period of 3 months or more
• Both acute and chronic diarrhoea can present a significant risk of life-threatening dehydration, particularly in children. If there are signs of serious dehydration refer to medical help immediately
• Dehydration indicators in adults

  • No urination or low urination with a dark colour
  • Dry skin and mouth
  • Excessive thirst
  • Fatigue, weakness, confusion and/or disorientation
• Dehydration indicators in young children and infants

  • No or low urinations, including infants not having a wet nappy for 3 or more hours
  • Dry skin, mouth and tongue
  • Fever above 39 degrees
  • No tears when crying
  • Drowsiness, lack of response or grumpiness
  • Sunken eyes, cheeks or abdomen
• Causes of chronic diarrhoea

  • Almost always a symptom of another underlying condition such as IBS or IBD conditions
  • Viruses typically lead to acute diarrhoea as most of the viral species that are associated with risks of diarrhoea are typically cleared by the immune system
  • Parasites and bacteria, in particular E, coli and C. Difficle commonly cause acute diarrhoea and are more commonly transmitted where hygiene is poor, such as developing countries, as such it is commonly the cause for travellers diarrhoea
  • Antibiotics can lead to dysbiosis resulting in diarrhoea due to their action in killing both bad (target) and good (normal gut biome) bacteria
  • Lactose intolerance can cause diarrhoea. Undigested lactose is osmotically active, causing osmotic diarrhoea and can also be used by certain types of gut flora which have a propensity to promote diarrhoea
  • Artificial sweeteners of the polyalcohol-sugar type can cause diarrhoea is consumed in sufficient quantities. This is because they are neither absorbed nor digested and are osmotically active, drawing water into the gastrointestinal tract, particularly the colon
  • Surgery involving partial resection of the intestines can sometimes cause diarrhoea due to changes in nutrient absorption
  • Gallbladder removal can result in diarrhoea as a decrease in bile acid decreases fat absorption
• Irritable Bowel Syndrome (IBS)


  A functional gastrointestinal disorder and is thus defined by a series of symptoms, rather than a specific cause
• IBS is more likely to be several different conditions
• IBS


  Classified into at least 4 different types of conditions and is considered by some as a gastrointestinal disorder and by others as a disorder involving both the gastrointestinal tract and its communication with the brain
• IBS


  Associated as a chronic condition resulting in abdominal pain, bloating, and cramping that is associated with defecation
• Clinically IBS


  Defined as recurrent abdominal pain on average at least 1 day a week in the last 3 months, associated with two or more of the following: related to defecation, associated with a change on the frequency of stool, associated with a change in form of stool
• Bristol Stool Scale


  Used to assist with the identification of the different forms of stool
• Bristol Stool Scale types

  • Type 1: Separate hard lumps, like nuts. Typically hard to pass
  • Type 2: Sausage-shaped but lumpy
  • Type 3: Like a sausage but with cracks in the surface
  • Type 4: Like a sausage or snake, smooth and soft
  • Type 5: Soft blobs with clear-cut edges
  • Type 6: Fluffy pieces with ragged edges, a mushy stool
  • Type 7: Watery, with no solid pieces, it is entirely liquid
• On the Bristol Stool Scale, types 1, 2, 6 and 7 are considered outside the normal range and are therefore used as a tool to help define the type of IBS present
• IBS sub-types


  • IBS with predominant constipation (IBS-C)
  • IBS with predominant diarrhoea (IBS-D)
  • IBS with mixed bowel habits (IBS-M)
  • IBS unclassified (IBS-U)
• IBS with predominant constipation (IBS-C)

  • Greater than 25% of bowel movements with Bristol stool types 1 or 2
  • Less than 25% of bowel movements with Bristol stool types 6 or 7
• IBS with predominant diarrhoea (IBS-D)

  • Greater than 25% of bowel movements with Bristol stool types 6 or 7
  • Less than 25% of bowel movements with Bristol stool types 1 or 2
• IBS with mixed bowel habits (IBS-M)

  • Greater than 25% of bowel movements with Bristol stool types 1 or 2
  • Greater than 25% of bowel movements with Bristol stool types 6 or 7
• IBS unclassified (IBS-U)


  Patients who meet diagnostic criteria for IBS but whose bowel habits cannot be accurately categorized
• First line treatment for IBS

  Lifestyle modification to try and eliminate or reduce triggers for IBS. This includes keeping a food diary to identify, then eliminate, food triggers, for most types of IBS, having a diet high in fibre, drinking plenty of water, making sure sleep is adequate, engaging in regular exercise
• Particular dietary changes are often recommended for IBS, however the clinical evidence supporting these is weak. This doesn't mean they don't work
• Inflammatory bowel disease (IBD)


  Involve chronic inflammation of the gastrointestinal tract and include both Crohn's disease and Ulcerative Colitis
• IBD are referred to as immune disorders but are also auto-immune disorders, given that the triggering antigen lead to an immune reaction that is not only directed against the foreign antigens but also against the persons own gastrointestinal lining