Constipation & IBS Flashcards by Jamie Barclay

Main 3 functions of the colon?

Waste products - modification, storage, evacuation
Water & electrolyte absorption (converts 2L of stool to 200g)
Bacterial flora & absorption of nutrients from bacterial digestion. Esp short chain FAs not absorbed in SI

How well did you know this?

Not at all

Perfectly

What is the function of the proximal colon (ascending and transverse?)

Fluid / electrolyte absorbtion and bacterial fermentation.

How well did you know this?

Not at all

Perfectly

What is the function of the distal colon (descending and sigmoid?)

Reservoir function - stool storage

How well did you know this?

Not at all

Perfectly

Normal colonic transit time?

24-40 hrs

How well did you know this?

Not at all

Perfectly

Proximal or distal?
Non-propulsive segmentation – generated by slow wave
activity which produces circular-muscle contraction
(produces appearance of segments or haustra)
– Mixing/ absorption of contents
• Mass peristalsis (1 to 3 x/day) – simultaneous SM
contraction over large confluent areas-portion of
contents propelled distally. Main form of propulsive motility.

Proximal

How well did you know this?

Not at all

Perfectly

What are the two major branches of the Enteric Nervous System in the GI tissues

Myenteric (Auerbach’s)

Submucosal (Meissner’s)

How well did you know this?

Not at all

Perfectly

Which parts of ANS innervate and what is function of Myenteric ENS

Parasymp and sympathetic

Motor control of both circular and longitudinal muscle = peristalsis

How well did you know this?

Not at all

Perfectly

Which parts of ANS innervate and what is function of Submucosal ENS

Parasympathetic only - secretomotor inervation of mucosa

How well did you know this?

Not at all

Perfectly

This disorder is when there is loss of ENS ganglia in the distal part of the colon, leading to potential blockage and enlargment of proximal colon.

Hirschprungs

How well did you know this?

Not at all

Perfectly

Two main types of contraction in normal colonic motility

LAPC - 100mmhg, 6x/day, moves more solid poo along & assoc with defecation

How well did you know this?

Not at all

Perfectly

This neurotransmitter increases contraction by prolonging the duration of HAPC

Acetylcholine

How well did you know this?

Not at all

Perfectly

Middle aged women, normal colonoscopy, watery diarrhoea - on histological exam= thickened subepithelial collagenous band OR incr lymphocytes in epith.

AUTOIMMUNE COLITIS = Collagenous or Lymphocytic

How well did you know this?

Not at all

Perfectly

2 most common idiopathic inflammatory bowel diseases?

Crohns & UC

How well did you know this?

Not at all

Perfectly

Young adults, malaise, anorexia, wt loss, bloody drha & mucus PR. Commonest cause of bloody drha in UK

UC = distal colon

How well did you know this?

Not at all

Perfectly

Vague pain and mild diarrhoea, young adult. Symptoms come and go. Apthous ulcers in mouth.

Crohns

How well did you know this?

Not at all

Perfectly

Most common location of volvulus, leading to ischaemia of bowel.

Splenic flexure - v long mesentery here, bowel easily twisted.

How well did you know this?

Not at all

Perfectly

3 most common infective causes of inflammation of colonic mucosa leading to bloody diarrhoea?

Campylobacter, Shigella, Salmonella

How well did you know this?

Not at all

Perfectly

Patient in hospital on long term antibiot. / enema / post-GI surgery. Diarrhoea caused by? Up to 20% of patients have this.

C difficile - causes Pseudomembranous colitis

How well did you know this?

Not at all

Perfectly

Virus that causes colitis - mucosa will look similar to UC

Cytomegalovirus CMV

How well did you know this?

Not at all

Perfectly

Protozoa, common in tropics not in UK, cause bloody diarrhoea, can lead to strictures and metastatic abcesses.

Amoebiasis - Entamoeba histiolytica

How well did you know this?

Not at all

Perfectly

Melanosis coli - pigmentation of bowel wall is caused by what type of medication?

Laxative excess

How well did you know this?

Not at all

Perfectly

A congenital condition malformation of part of colon - leading to blockage requiring surgery. Poss. assoc with Down’s.

Intestinal atresia

How well did you know this?

Not at all

Perfectly

Herniation of mucosa through bowel wall - form little pouches.
Can become inflamed with fibrosis.
Can lead to stricture formation.
Present with pain, altered bowel habit, bleeding, perforation, obstruction.

Diverticular disease

Affect of hyper and hypo thyroidism on gut motility?

Hyper - increases gut motility & diarrhoea (hormones act on sympathetic system)
Hypo - constipation and reduced gut motility

``` Intermittent, long standing symptoms. Alternating constipation and diarrhoea. Abdominal pain/cramps. 4x more common in women. age 20 - 40 Functional / idiopathic ```

Irritable Bowel Syndrome

Aut dominant condition - mutation in APC gene ( a tumour suppressor gene on chr 5) Causes multiple adenomas (100+) - develop adenocarcinoma of colon. Treatment surgery / colectomy before 25yo

Familial adenomatous polyposis.

Four types of drugs that can cause CHRONIC constipation 1. Common painkiller etc 2. To treat anaemia 3. Trtment for ganglions sending pain signals 4. Similar to above - neuromuscular agent

1. Opiates 2. Iron 3. Ganglion blockers (block paras and symp = nicotinic blockers) 4. Anticholinergics eg atropine

3 metabolic /endocrine causes of chronic constipation:

1. Hypothyroidism 2. Hypercalcaemia 3. Hypokalaemia

2 neuromuscular causes of chronic constipation

Hirschprungs | Spinal cord lesions

"idiopathic" cause of constipation in person with learning difficulty - "never learnt" to toilet properly. Sounds like a transformer villain.

Megarectum - gets full and compacted.

Other than megarectum, 3 causes of Obstructive Defecaetion Syndrome (ODS) (most common in multiparous women)

1. Rectocoele 2. Rectal intususseption 3. Anismus

Patient being treated for psychosis complaining of constipation - possible cause?

Antipsychotic medication e.g. haloperidol

True / false, >40yo w. bleeding PR & loose stool for 4 weeks = Urgent Suspected Cancer (USC)?

FALSE - needs to be PR bleed and loose stool for 6 weeks in younger patients.

True or False: >60yo with EITHER rectal bleed OR loose stool for >6 weeks = USC?

TRUE - only 1 req for more than 6 weeks in older patients

True / false: RIF mass, rectal mass or unexplained anaemia are all possible symptoms for USC

True

Constipation: In a colonic transit study (swallowing bits of plastic for 3 days then xrayday 5) the stuff is scattered throughout the colon. What is the main problem?

Colonic motility is low - hypomotility or colonic inertia

Constipation: In a colonic transit study (swallowing bits of plastic then xray) after 24 hrs the stuff is concentrated in the rectum. What is the main problem?

Blockage of rectum / anus area.

What does manometry measure (2)

``` Resting pressure (internal sphincter) Maximul squeeze (external sphincter) ```

Primary investigation for chronic constipation? (old and new)

Barium enema, contrast CT

Primary constipation caused by?

Functional / idiopathic

Secondary / organic constipation caused by?

Drugs / medical condition

Laxatives: 4 types, define and give examples: | 1. Bulk forming

``` Types: ispaghula husk, methylcellulose, sterculia Action: i. Retain fluid in stool ii. Incr faecal mass iii. Incr peristalsis iv. Soften stool ``` For small hard stools/poor fibre

Laxatives: 4 types, define and give examples: | 2. Osmotic

``` Type: Lactulose, macrogols Action: i. Incr fluid in colon = distension ii. Stool softening iii. Peristalsis stimulating ``` For impaction / chronic constip

Laxatives: 4 types, define and give examples: | 3. Stimulant

Stimulate colonic nerves=peristalsis (senna, bisocodyl, sodium picosulfate) Acute - short term relief

Laxatives: 4 types, define and give examples: | 4. Surface wetting

Docusate, poloxamer Reduce surface tension of stool - water can then penetrate & soften. For hard dry faeces painful to pass.

3 main methods of pain management, all antispasmodics, with IBS

1. Anti cholinergics = SM relaxants (dicyclomine/hyoscine) 2. Antimuscarinics (mebeverine/alverine) 3, Peppermint oil (colpermin)

Alternative pain management of IBS using drugs

Anti-depressants (serotonin & anti cholinergic effect)

Anti-epilepsy drug, also used in bipolar disorder, causes constipation.

Carbamazepine

These two metals can cause constipation (supplements or antacids)

Aluminium Calcium

Calcium channel blocker used to treat HT - causes constipation

Verapamil

First 2 steps of treating constipation before using pharamcology

``` Incr fluids (2L / day,) reducing caffeine & diuretics Incr fibre 18-30g/day min ```

Contraindications for arachis oil enema (softner - used for impaction)

Peanut allergy

Cautions for use for phosphate enema (osmotic)

Renal impairment Heart failure

Selective serotonin 5HT4 receptor agonist with introduced for treatment of chronic constipation in women where other agents have failed.

Prucalopride

Acetylocholine and substance P are stimulatory / inhibitory neurotransmitters in the ENS

Stimulatory

VIP and Nitric oxide are stimulatory / inhibitory neurotransmitters in the ENS

Inhibitory