Week 209 - IBS/Constipation Flashcards
Which Portacaval anastomosis will result in Anorectal Varices?
Superior Rectal Veins draining via Middle+Inferior Rectal Veins directly into systemic circulation
Which Portacaval anastomosis will result in Caput Medusae?
Paraumbilical Veins draining via Superior epigastric veins directly into systemic circulation
Which Portacaval anastomosis will result in Oesophageal Varices?
Left Gastric Vein draining via the azygous directly into systemic circulation
Which Portacaval anastomosis will result in Ascites?
R, L and Middle Colic Veins draining via Paravertebral, Renal, Gonadal, Adrenal, Paravertebral Veins into the systemic circulation
Which Portacaval anastomosis will result in Splenomegally?
Portal Vein will directly drain into the IVC
Where do Secondary Metastases from Colon Cancers end up?
Liver
Paraaortic Lymph Nodes
What is a Carcinoid Tumour?
Tumour of Endocrine Cells
What is Carcinoid Syndrome?
Bronchial wheezing, Skin Flushing & Diarrhoea caused by 5-HT (serotonin) release by a Carcinoid Tumour
Where are Peyer’s Patches found?
Terminal Ileum
What does the Myenteric Plexus supply in the Gut?
Motor to Longitudinal & Circular Muscle
Secretomotor to mucosa
What does the Myenteric Plexus supply in the Gut?
Motor to Muscularis Mucosae
Mucosal Receptors
Which transmitters have a Stimulatory effect on the colon?
ACh & Substance P
Which transmitters have an Inhibitory effect on the colon?
VIP & NO
What Neuromuscular Disease can give rise to Constipation?
Spinal Cord Lesions
Hirschsprung’s Disease
What Metabolic Disease can give rise to Constipation?
Diabetes Hypothyroidism - slow transit+motility Hypercalcaemia Hypokalaemia Phaeochromocytoma Uraemia
What drugs can give constipation?
Opiates Iron Ganglion-blockers Non magnesium antacids Calcium-channel blockers Inadequate thyroid supplementation Anticholinergic Many psycotropic drugs
What innervation does the Internal Sphincter have?
Only Autonomic (i.e. involuntary)
What are the possible causes of Faecal Incontinence (categories)?
Neurogenic incontinence
Myogenic incontinence
Combination of both
What are the possible causes of Obstructed Defaecation Syndrome (ODS)?
Rectocoele
Rectal Intussusception
Anismus
Idiopathic megarectum
What effects does Sacral Neuromodulation (SNS) have?
Increases propagated (ante grade) colonic contractions Normalises pathologies/physiologies common to both continence & constipation
What are the two causes of Constipation?
Functional Constipation (aka Primary) Organic Constipation (aka Secondary) - e.g. due to drug or medical condition
What are the Rome criteria for constipation?
Bowel movements <3 times a week
What CNS diseases can give constipation?
Parkinson’s Disease
Multiple Sclerosis
CVA
Spinal Injury
What is the Colonic Transit Study?
Pt takes one capsule daily for 3 days X-ray on day 5 If <5 remain = normal Most rings SCATTERED= hypomotility Most rings in rectosigmoid = Outlet obstruction
Which laxatives should be offered first for constipation?
1) Bulk-forming laxative
2) If stools still hard, Osmotic Laxative
3) If stools soft but person still finds them hard to pass, stimulant laxative
Give some examples and the action of BULK-FORMING LAXATIVES
Ispaghulahusk, methylcellulose
Retain fluid, increasing faecal mass -> Stimulate Peristalsis
Give some examples and the action of OSMOTIC LAXATIVES
Lactulose, Macrogols
Increase fluid in large bowel (soften + stim. peristalsis)
Give some examples and the action of STIMULANT LAXATIVES
Peristalsis by stimulating colonic nerves (Senna)
Or Colonic & Rectal Nerves (Bisacodyl, sodium picosulfate)
How should you treat constipation?
1) Adjust any constipating medication
2) Advise about exercise, fluid intake, dietary fibre
3) Offer oral laxatives
How do you manage Pain in IBS?
Antispasmodics
Anticholinergics (dicyclomine/hyoscine)
Antimuscarinic agents (mebeverine/alverine citrate)
Peppermint oil (Colpermin)
Which antidepressants are likely to give DIARRHOEA as a side-effect?
Amitryptyline
Imipramine
Clomipramine
Which antidepressants are likely to give CONSTIPATION as a side-effect?
Citalopram
Sertaline
Paroxetine
Fluoxetine
What effect do Probiotics have in IBS?
Improvement in symptoms - including pain and bloating
What is Lubiprostone?
A selective C-2 chloride channel activator that stimulates water secretion into the lumen
What is Prucalopride?
Selective Serotonin 5-HT4 Receptor Agonist
Stimulates Peristalsis
What is a Fistula?
Abnormal Tract between two epithelial or endothelial lined surfaces
What autoimmune conditions can affect the large bowel?
Microscopic Colitis
either Collagenous colitis or lymphocytic colitis
Which areas of the bowel does Ulcerative Colitis affect?
Colon & Rectum
Crypt Abscesses
Commonest cause of bloody diarrhoea
Which areas of the bowel does Crohn’s Disease affect?
Mouth to Anus
Full thickness of wall involved, “cobblestone appearance”
What viruses can affect the colon?
CMV
What protozoal infections can affect the colon?
Amoebiasis (entamoeba histolytica)
What is Hirschsprung’s Disease?
Congenital aganglionic megacolon
No ganglion cells in submucosal & myenteric plexuses
Enlarged dilated proximal large bowel because of obstruction
What effects on the bowel will Thyroid Disease have?
Hyperthyroidism - ↓Gut motility + Diarrhoea
Hypothyroidism - Constipation
What is FAP?
Most commonly mutation in APC
Autosomal Dominant
Multiple Adenomas
Develop Adenocarcinoma of colon
What are the imaging modalities for Colorectal Cancers?
Ultrasound Barium Enema CT CT Colonography MRI
What are the advantages of CT Colonography?
Quicker and less technically demanding than either colonoscopy pr barium enema
What is good and bad about Endo-Rectal USS?
Great for T1-T4
Large Bulky Tumours = not so good
Painful Tumours = not so good
What are the possible PRIMARY CAUSES of Constipation?
Never Learnt
Dysmotility
Mechanical (e.g. ODS)
What are the possible SECONDARY CAUSES of Constipation?
Obstruction
Drugs
Metabolic
What are the possible Surgical Options for dysmotility?
Colectomy & IRA (ileo-rectal anastomoses)
SNS
ACE (Anterograde colonic enema)
What are the operations that can help with rectal prolapse?
Open rectopexy - mesh put in front
Perineal procedure - stitched up
