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Generally defined as passing loose watery stools at least 3 times a day
Best defined in terms of ○ frequency ○ consistency ○ volume or weight Consistency is determined by water holding capacity of the stool ( amount of non-bound free water ) and this possibly best defines the concept of diarrhoea Stool weight > 200 g/D- often regarded as Upper Limit of normal Other terms often associated / used ○ Frequency – relates to number of stools passed ○ Urgency – sensation of need to defecate without delay ○ Incontinence ( faecal ) uncontrolled passage of solid or liquid faeces at socially inappropriate time and places ○ Faecal impaction or loading- when rectum & often lower colon is full with hard or soft stool –> can lead to overflow diarrhea
How commmon–Noravirus is associated with approximately 1/5th of all infectious diarrhoea cases ( adults & children ) Incidence of rotavirus has reduced due to vaccination Chronic diarrhoea is often caused by inflammatory bowel disease ( Crohn’s and Ulcerative colitis ) Acute diarrhoeal infection is a leading cause of hospitalization, out-patient visits and lost quality of life ( both in domestic setting & those who are travelling) Most commonly isolated pathogen ( acute diarrhoea ) include noravirus , sapovirus , Campylobacter spp and rotavirus ) In the USA management of acute diarrhoea costs $ 150 million upwards to the healthcare economy
Pathophysiology
Osmotic diarrhoea ○ soluble compound cannot be absorbed by the small intestine –> draws fluid into intestinal lumen ○ eg ingestion of non-absorbable substance as a laxative like Mg sulphate or Mg containing antacid ○ generalized malabsorption eg coeliac disease and pancreatic insufficiency ○ consuming large quantities of artificial sweeteners as sorbitol Secretory diarrhoea ○ both active intestinal secretions of fluid and electrolytes as well as decreased absorption ○ net fluid loss ○ Enterotoxins –> cholera , E.coli , C.difficile ○ Neurohormonal agents eg VIP , bile salts ○ laxatives as docusate Secretory diarrhoea continues on fasting Inflammatory diarrhoea- damage to intestinal mucosal cells–> loss of fluid and blood + defective absorption of fluid and electrolytes- eg include ○ infective causes as shigella ○ inflammatory conditions as ulcerative collitis , Crohn’s , coeliac Abnormal gut motility – eg diabetic and hyperthyroid diarrhoea
Acute diarrhoea –Most acute episodes are infectious- look for supporting information as ○ fever ○ recent contact with a person with diarrhoea ○ exposure to possible source ♦ meals outside , takeaways ♦ farm visit , camping ○ travel history Drug related- new drugs particularly antibiotics Stress and anxiety Abdominal symptoms – eg marked tenderness ? appendicitis Radiation treatment CV dis or hypercoagulable state –> risk intestinal ischaemia
Red flags –Blood in stool Recent hospital admission or antibiotic Rx- consider antibiotic associated diarrhoea Persistent vomiting Weight loss Painless , watery , high volume diarrhoea ↑↑ risk dehydration Nocturnal symptoms disturbing sleep ↑↑ risk organic cause
Consider admission –Risk dehydration or shock- vomiting and unable to retain fluids Age ( people < 60 ↑ risk of complications ) Fever Bloody diarrhoea Abdominal symptoms as pain and tenderness Co-morbidities as ○ immunodeficiency ○ lack of stomach acid ○ inflammatory bowel disease ○ valvular heart disease ○ diabetes mellitus ○ renal impairment ○ rheumatoid disease , SLE ○ drugs as immunosuppresants or systemic steroids , PPIs ,ACE , diuretics
Check stool sample-Systemically unwell- needs hospital admission and or antibiotics Blood or pus in stool Immunocompromised state Recent antibiotics use or hospital admission ○ request specifically for Clostridium difficile History of foreign travel- ask for ova , cysts and parasites Diarrhoe > 2 weeks and Giardia is suspected Reassurance
Consider public health advice –Suspected public health hazard ○ diarrhoea in food handlers , health-care workers , elderly residents in care homes Outbreak in community or family Contacts of people infected with organisms as E.coli 0157:H7 ( may have serious clinical sequeale )
Chronic diarrhea causesColonic ○ colonic neoplasia ○ UC and Crohn’s ○ microscopic colitis (watery nocturnal diarrhoea in older ♀ often associated with coeliac disease ) Small bowel ○ Coeliac disease ○ Crohn’s ○ other small bowel enteropathies as ♦ Whipple’s ♦ Tropical sprue ♦ Amyloid ♦ Intestinal lymphangiectasia ○ Bile acid malabsorption ○ Disaccharide deiciency ○ Small bowel bacterial overgrowth ○ Mesenteric ischaemia ○ Radiation enteritis ○ Lymphoma ○ Giardiasis ( & other chronic infections )
Pancreatic ○ Chronic pancreatitis ○ Pancreatic carcinoma ○ Cystic fibrosis Endocrine ○ Hyperthyroidism ○ Diabetes ○ Hypoparathyroidism ○ Addison’s disease ○ Hormone secreting tumours ♦ VIPoma ♦ gastrinoma ♦ carcinoid Other ○ Factitious diarrhoea ( laxative use ) ○ surgical causes- eg small bowel resection , internal fistulae ○ Drugs ○ Alcohol ○ Autonomic neuropathy
investigations –FBC- anaemia or ↑ platelet count ( inflammation ) LFT Tests for malabsorption ○ Calcium ○ Vit B12 and red cell folate ○ Ferritin TFT ESR and CRP Coeliac screen Stool sample ○ culture and sensitivity ○ ova cysts and parasites Three specimens 2-3 days apart ○ consider checking for C.difficile
Medications –Allopurinol ARB’s Antibiotics Digoxin Colchicine Cytotoxic drugs ( eg chemotherapy , methotrexate ) H-2 receptor antagonists Laxatives Magnesium- containing antacids Metformin NSAIDs NSAID’s PPI’s SSRI’s Statins Theophylline Thyroxine High dose vitamin C
Symptoms suggestive of Colorectal cancer Age 40 + or older ○ rectal bleeding with a CIBH towards loose stools and/ or ○ ↑ stool frequency persisting 6 weeks or more Right lower abdominal mass – consistent with involvement of large bowel Palpable rectal mass Aged 60 or over with ○ CIBH to looser stools and/ or ↑ frequent stools persisting for 6 weeks or more with ot without rectal bleeding Men of any age with unexplained iron deficiency anemia and a Hb of 11 or less Non menstruating ♀ with unexplained iron deficiency anemia and a Hb of 10 or less
LINKS AND RESOURCES
PATIENT INFORMATION
Diarrhoea information from NHS Inform Scot https://www.nhsinform.scot/illnesses-and-conditions/stomach-liver-and-gastrointestinal-tract/diarrhoea
Travellers diarrhoea from Fit for Travel a very useful resource https://www.fitfortravel.nhs.uk/advice/disease-prevention-advice/travellers-diarrhoea.aspx
Norovirus patient information leaflet from Buckinghamshire Healthcare NHS Trust https://www.buckshealthcare.nhs.uk/Downloads/Patient-leaflets-Infection-Control/Diarrhoea%20and%20vomiting%20caused%20by%20Norovirus%20-%20information%20for%20patients.pdf
Sothercross Medical Library on diarrhoea https://www.southerncross.co.nz/group/medical-library/diarrhoea-causes-treatment-prevention
Clostridium difficile –PIL https://www.cuh.nhs.uk/infection-control/well-known-infections-faqs/clostridium-difficile-diarrhoea
INFORMATION FOR CLINICIANS
Guidelines for the investigation of chronic diarrhoea in adults: British Society of Gastroenterology, 3rd edition Ramesh P Arasaradnam1,2,3, Steven Brown4, Alastair Forbes5, Mark R Fox6,7, Pali Hungin8, Lawrence Kelman9, Giles Major10, Michelle O’Connor9, Dave S Sanders4, Rakesh Sinha11, Stephen Charles Smith12, Paul Thomas13, Julian R F Walters14 https://gut.bmj.com/content/67/8/1380