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Diarrhoea - Summary Medicine
Medicine (A100)
Queen Mary University of London
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DIARRHOEA (1) Define diarrhoea Passage of 3 or more abnormally loose or liquid stools per day of stool produced in 24 hours Acute days in duration Persistent days in duration Chronic days in duration Able to take a history of a patient with diarrhoea Determine frequency of stools Determine consistency of stools Determine if stool is fatty (pancreatic insufficiency, coeliac disease, biliary obstruction) or contains blood (UC or campylobactreri, shigella, salmonella, pseudomembranous colitis, ischaemic colitis) or mucous (seen in UC and colonic infections) Check for red flag symptoms blood in stool, weight loss, recent antibiotic therapy (thinking C. diff), volume diarrhoea (dehydration risk), nocturnal symptoms (organic cause likely) Features of infection fever, recent travel, contact with another source of infection, possible source of food poisoning Associated symptoms Abdominal pain (invasive organisms) Nausea (Cryptosporidium) Vomiting (preformed toxins) Flatus (Giardia) Tenesmus (UC) Drug history PPIs, NSAIDs, laxatives, antibiotics, quinine Stress and anxiety Understand the assessment of a patient with diarrhoea Assessing hydration status Dry mucous membranes Decreased skin turgor Increased capillary refill time Hypotension Tachycardia Abdominal examination Check bowel sounds Check for tenderness Check for distention Check for hepatomegaly (Salmonella, amoebic liver disease) Rectal examination for characterising stool content, presence of mucous or blood Systemic features Signs of hyperthyroidism Aphthous stomatitis in coeliac and IBD Dermatitis herpetiformis in coeliac Erythema nodosum or pyoderma gangrenosum in IBD Clubbing in IBD List the causes of infectious diarrhoea and outline the diagnostic features in the history Viral Norovirus most common viral cause, high infectious, acute onset vomiting and watery diarrhoea after exposure, diagnosis is clinical (PCR possible), treatment is supportive with hydration and agents, usually Rotavirus most common cause of gastroenteritis in children, 2 day incubation period with days of watery diarrhoea, vomiting, fever and abdominal pain, supportive treatment, routine vaccination Astrovirus less severe than norovirus Adenovirus enteric adenovirus that mainly affects children CMV usually asymptomatic but can cause colitis (with bloody diarrhoea), hepatitis, retinitis and pneumonia in immunocompromised Bacterial Salmonella (most common cause of infective diarrhoea) bloody diarrhoea (no blood if mild) found in undercooked eggs, poultry and meat (onset Campylobacter (second most common) flu like symptoms followed crampy abdominal pain and explosive bloody diarrhoea with mucous (no blood if mild), found in undercooked chicken and meat, unpasteurised milk and water (onset E. coli (onset o ETEC enterotoxic, most common cause of diarrhoea o EAEC enteroaggregative, causes watery diarrhoea in children o o EHEC enterohaemorrhagic, causes bloody diarrhoea and haemolytic uraemic syndrome (commonly found in ground beef) EIEC enteroinvaisve, causes invasive dysentery (bloody diarrhoea) like Shigella Shigella bloody diarrhoea with abdominal pain and vomiting (onset Staphylococcus aureus found in unpasteurised milk and cheese and meat left at room temperature, can have toxin production (30 min onset with quick remission) Clostridium difficile bloody diarrhoea, antibiotic associated, causes pseudomembranous colitis Listeria found in cold meat and soft cheese, severe in Esqpregnant women foetal loss Vibrio cholerae human and aquatic reservoirs that can cause epidemics Yersinia bloody diarrhoea, found in undercooked pork, pain in RIF like appendicitis Bacillus cereus emetic or diarrhoeal toxins from undercooked rice (30 min onset with quick remission) Parasitic Entamoeba histolytica spread cysts in faecally contaminated food, often carriers are asymptomatic with disease occurring up to years after infection with intestinal and (liver, skin, lungs, brain) disease Cryptosporidium transfer via infected faeces with increased risk in immunocompromise Giardia lamblia ingested cysts from open water (e. mountain streams), causes malabsorption Rapid onset after ingestion of food Bloody diarrhoea Abdominal pain Fever Leucocytosis Inflammatory bowel disease Diarrhoea for months with blood or mucous Crampy abdominal pain Systemic signs such as arthritis, skin changes and eye changes Understand the treatment options for diarrhoea Oral rehydration (better than IV) Codeine phosphate or loperamide after each stool (max but avoid in colitis as can increase risk of toxic megacolon Avoid antibiotics unless systemic upset If antibiotic associated diarrhoea, give probiotics such as lactobacilli Describe the management of acute infective diarrhoea Hydration Oral rehydration solutions are best Containing water, sodium, chloride, bicarbonate, potassium, citrate and glucose Antibiotics Indicated for all shigella, ETEC, v. cholerae, C. diff Indicated if severely ill or immunocompromised campylobacter, yersinia, EPEC, salmonella Not indicated EHEC, viruses Empirical therapy o 1st line quinolone o 2nd line azathioprine o o 3rd line rifaximin Note: and doxycycline are no longer used due to widespread resistance Choice after culture o E. coli fluoroquinolone o Shigella fluoroquinolone or o o Vibrio cholerae tetracycline or fluoroquinolone Salmonella fluoroquinolone or o o Campylobacter erythromycin or fluoroquinolone Yersinia tetracycline or or fluoroquinolone Describe the pathophysiological mechanisms that may produce diarrhoea Osmotic increased osmotic pressures within the lumen prevents uptake of water, allowing it to remain in the lumen Malabsorption lactose intolerance, coeliac disease Mannitol ingestion Distinguishing feature stops with fasting Secretory excess secretion of water that cannot be fully reabsorbed Bacterial toxins Vibrio cholerae, ETEC, EHEC, Bacillus cereus, S. aureus VIPoma Drugs destruction of the epithelium results in exudation of serum and blood into the lumen and widespread destruction of absorptive epithelium Inflammatory bowel disease Coeliac disease Bacteria Salmonella, EIEC, Campylobacter Viruses rotavirus, norovirus Protozoa Giardia, cryptosporidium Motility disorders increased motility can decrease available time for absorption, leading to increased fluid remaining within the lumen Understand the importance of C. difficile causing pseudomembranous colitis Clinical features Pyrexia Colic pain Watery diarrhoea Massively raised CRP and WCC Decreased albumin Yellow adherent plaques (pseudomemrbanes) and colitis on colonoscopy Toxic megacolon on AXR Risk factors Antibiotics (especially broad spectrum) Increasing age Severe underlying disease Presence of NG tube medication ITU Long hospital stay Predictors of fulminant C. diff colitis years old Past C. diff infection Use of drugs Severe leucocytosis Haemodynamic instability Detection Rapid screening test Followed specific toxin ELISA test Perform AXR to detect toxic megacolon Flexible sigmoidoscopy is usually diagnostic Treatment
Diarrhoea - Summary Medicine
Module: Medicine (A100)
University: Queen Mary University of London
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