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Flashcards in Week 209 - IBS Deck (25)

What does the Rome III state in the disgnosis of IBS?

Must experience 2 of the following 3 criteria to be disgnosed and or experience at least 3 days a month for 3 months recurrent abdo pain:
1. Improvement on defecation
2. Onset assoc with change in frequency of stool
3. Onset assoc with change in form of stool


What symptoms should provoke a thorough investigation?

The Rome III criteria along associated with: rectal bleeding, weight loss, nocturnal pain, fever and a clinical suspicion of organic diarrhoea


What are the 3 principle subtypes of IBS?

1) IBS with constipation (>25% hard stools, 25 loose/watery),
2) IBS with diarrhoea (>25% loose/watery, <25% hard)
3) mixed IBS


What do raised stool calprotectin and / or lactoferrin imply?

Inflammation, which could be due to IBD rather than IBS and needs further investigation


What condition might lactose, Senna and Magnesium hydroxide be used to treat?

Chronic constipation


What are the principle functions of the large bowel?

> modification, storage and evac of waste prods of digestion and metabolism
> extraction of water and electrolytes from fluid ileal contents
> maintenance of bacterial flora and absorption of nutrients derived from bacterial degradation of luminal contents
> absorbs short-chain fatty acids formed by catabolism of carbs in SB


What is Hirchsprung's Disease?

Where a section of large bowel is permanently contracted/narrowed causing a blockage for stools. Often effects sigmoid colon and rectum. Usually diagnosed soon after birth when meconium not passed - surgically treated


Where is the myenteric plexus if the large bowel located, which parts of the NS are incorporated and what motor action does it provide to the colon?

Between the longitudinal and circular muscle of the bowel wall. Sympathetic and parasympathetic nervous systems. Motor function to longitudinal and circle muscle and secretomotor action to mucosa of colon


Where is the submucous plexus locate in the colon, what part of the NS is involved with it and what does it innervate?

Between the circular muscle and the muscularis mucosae. Only parasympathetic. Motor innervation to muscularis mucosae and mucosal receptors


What is normal colonic transit time?



What types of motility occur in the proximal and distal colon?

Proximal - non-propulsive segmentation (slow wave activity of circular muscle contraction) and mass peristalsis 1-3x a day (simultaneous submucosal contraction over large area) main form of propulsive motility
Distal - primarily non-propulsive


What neurotransmitters are stimulatory in the colon?

Acetylcholine and Substance P


What neurotransmitters are inhibitory in the colon?

Vasoactive intestinal polypeptide (VIP) and Nitric Oxide
Both are vasodilators


Hoe does acetylcholine enhance colonic contractions?

It increases the duration of the regular slow waves in circular muscle (which precede expulsion of faeces)


Define constipation

Infrequent passage of small amounts of faeces leading to symptoms


What are the two main mechanisms for constipation?

1) insufficient luminal residue
2) abnormalities of neuromuscular activity (congen or acquired)


Give some causes of chronic constipation

Poor diet, purgative abuse, idiopathic e.g. IBS, metabolic (hypothyroidism, hypercalcaemia), drugs (opiates, iron, anticholinergics), neuromuscular disease (spinal cord lesions, Hirchsprung's), psychiatric


What does the technique of manometry do and how?

It measures/assesses anorectal contractility and presence of the rectosphincteric reflex - a balloon is inflated to distend the rectum and a pressure sensor at the internal anal sphincter
Can be used to diagnose Hirchsprung's Disease in which there is an absence of this reflex


Describe the rectosphincteric reflex

As rectal pressure increases the internal anal sphincter tone should decrease to allow of defaecation


What is needle EMG (electromyography)

A technique used in the evaluation of sacral neurological function. The pudendal nerve, innervating the external anal sphincter is a good indicator of sacral neuropathic lesion


Anal endosonography (another technique useful in investigation of faecal incontinence)

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What is anismus?

Failure of pelvic floor muscles to relax during attempted defaecation resulting in difficulty emptying bowels


What is tenesmus?

The feeling of incomplete emptying of bowel


Want are the main causes of obstructed defaecation?

Rectal intussusception (prelim phase of rectal prolapse)
Idiopathic megarectum


What are the symptoms of rectal intussusception?

Incomplete evac
Rectal fullness or pressure
Perianal pain