Management of Diarrhoea and Constipation Flashcards
Diarrhoeas
Acute < 14 days
Persistent > 14 days
Chronic > 30 days
Inflammatory diarrhoea
Viral, bacterial, parasitic infection
Radiation injury
IBD
Inflammatory diarrhoea symptoms
Mucoid and bloody stool
Tenesmus (urge to empty bowels when they are empty)
Fever
Crampy abdominal pain
Histology of GI tract = abnormal
Non-inflammatory diarrhoea
Osmotic
Secretory
Non-inflammatory diarrhoea symptoms
Watery
Frequent stool > 10-20 times a day
High volume depletion
Histology of GI tract = preserved
Osmotic diarrhoea
Presence of unabsorbed solute
Small stool volume
Stops/improves with diet
Maldigestion
Secretory diarrhoea
Altered transport of ions across mucosa
Increased secretion; decreased absorption
Not affected by diet
Infectious bacterial diarrhoea causes
E.coli
Campylobacter
Salmonella
C.Diff
Listeria
Vibrio cholerae
Infectious viral diarrhoea causes
Rotavirus
Norovirus
Adenovirus
Astrovirus
Infectious protozoal diarrhoea causes
Entamoeba histoltica
Giardia lamblia
Cryptosporidium
Non-infectious CV drugs causing diarrhoea
Digoxin
Quinidine
Propranolol
ACE inhibitors
Non-infectious GI drugs causing diarrhoea
Antacids (Mg salts)
Laxarives
H2 antagonists
Non-infectious endocrine drugs causing diarrhoea
Oral hypoglycaemic agents
Thyroxine
Non-infectious antibiotics causing diarrhoea
Amoxicillin
Cephalosporins
Erythromycin
Absorption
Water follows movement of electrolytes and glucose
Cl- transport in intestine
Na+/K+/2Cl- cotransporter
Actively driven by low intracellular Na+
Na+ and water enter lumen by paracellular transport
Vibrio cholerae
Cholera toxins enter cells
Activates G protein > activates adenyl cyclase
Increases cellular cAMP > activation of PKA
Phosphorylation of Cl- channel
Increased efflux of Cl- and water
Diarrhoea
Increased motility
Reduction in intestinal transit time = inadequate absorption
Cholinergic drugs - Pilocarpine
Anticholinesterase activity drugs - Donepezil
Anti-motility drugs
Diphenoxylate + atropine
Codeine phosphate
Racecadotril
Diphenoxylate MOA
μ opioid receptor on neuronal varicosities
Activation decreases ACh release
Peristalsis decrease
Segmental contraction increase
Racecadotril MOA
δ opioid receptor decreases cellular cAMP levels
Decreased Cl- and water
Enkephalins are endogenous activators
Prodrug - metabolised to thiorphan
Thiorphan is enkephalinase inhibitor
Opiates side effects
Rebound constipation
CNS affects
opioid dependance
Constipation
Heterogeneous disorder
Primary
Secondary
Constipation symptoms
< 3 bowel movements per week
Straining
Lumpy/hard stool
Sensation of anorectal obstruction
Manoeuvring required to defaecate
