Infective diarrhoea
Definitions
[edit | edit source]- Diarrhoea has a variable definition, but ultimately reflects increased water content of the stool. Can be due to either impaired water absorption and/or active water secretion by the bowel.
- Acute <14 days
- Persistent 14-30 days
- Chronic >30 days
- Invasive diarrhoea (dysentery) is diarrhoea with visible blood or mucus, and is commonly associated with fever and abdominal pain.
- STEC, shigella, campylobacter, salmonella, IBD, ischaemic colitis
- Begins with diarrhoea but progresses to fever and systemic illness - Listeria (think stiff neck or pregnant women) or typhoidal illness (if returned from overseas)
Aetiology of acute diarrhoea
[edit | edit source]- Acute infections (majority of cases)
- Viruses (most common)
- Bacteria (most common in severe cases)
- E. Coli has subtypes enterotoxigenic (ETEC), enteropathogenic (EPEC), enteroinvasive (EIEC), enteroaggregative (EAEC) and shiga toxin-producing (STEC)
- Protozoa (more commonly chronic)
- Amoebic dysentery - Entamoeba histolytica
- Giardia lambia - freshwater ingestion
- Cryptosporidium - seen with HIV
- Schistosomiasis - fluke infection from a freshwater snail
- Non-infectious (more common in persistent/chronic)
- Toxins
- Drugs
- Location:
- Small bowel - watery, large volume, associated with abdo cramping, bloating and gas
- Colon: frequent regular small volume and often painful bowel movements. Fever and blood are common.
Pathophysiology
[edit | edit source]- Classify based on mechanism
- Diarrhoea secondary to altered mucosal transport or secretory dysfunction
- Can be caused by toxins from Staph, E coli, Vibrio cholerae
- VIP and gastrin and calcitonin
- Occurs independent of dietary intake and does not subside with fasting
- No significant stool osmotic gap
- Osmotic diarrhoea
- The presence of osmotically active, poorly absorbed solutes in the bowel lumen that inhibit normal water and electrolyte absorption
- Lactulose, magnesium, undigested lactose
- Increased osmotic load can be measured in the stool
- Subsides with fasting
- Diarrhoea secondary to malabsorption
- Pancreatic insufficiency, biliary disease, Crohn's, coeliac, intestinal lymphangiectasia
- Bile salts
- Exudative diarrhoea
- Anything producing blood, pus or protein
- Diarrhoea secondary to altered bowel motility
- Diarrhoea secondary to altered mucosal transport or secretory dysfunction
- Classify based on location
- Right-sided colitis is classically salmonella, campylobacter, or yersinia
| Likely pathogens | Mean incubation period | Classic/common food sources | Other epidemiologic clues and background | Treatment | |
| Watery diarrhea | Norovirus | 24 to 48 hours | Shellfish, prepared foods, vegetables, fruit |
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| Clostridioides (formerly Clostridium) difficile* | N/A | N/A |
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| Clostridium perfringens | 8 to 16 hours | Meat, poultry, gravy, home-canned goods | |||
| Enterotoxigenic Escherichia coli | 1 to 3 days | Fecally contaminated food or water |
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| Other enteric viruses (rotavirus, enteric adenovirus, astrovirus, sapovirus) | 10 to 72 hours | Fecally contaminated food or water |
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| Giardia lamblia | 7 to 14 days | Fecally contaminated food or water |
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| Cryptosporidium parvum | 2 to 28 days | Vegetables, fruit, unpasteurized milk |
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| Listeria monocytogenes | 1 day (gastroenteritis) | Processed/delicatessen meats, hot dogs, soft cheese, pâtés, and fruit |
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| Cyclospora cayetanensis | 1 to 11 days | Imported berries, herbs |
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| Cholera | Profuse watery diarrhoea | Supportive/azithromycin | |||
| Inflammatory diarrhea
(fever, mucoid or bloody stools)¶ |
Nontyphoidal Salmonella | 1 to 3 days | Poultry, eggs, and egg products, fresh produce, meat, fish, unpasteurized milk or juice, nut butters, spices |
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| Typhoidal salmonella (subtypes of Salmonella bacteria which can cause typhoid fever) | Meat/eggs |
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| Campylobacter spp | 1 to 3 days | Poultry, meat, unpasteurized milk |
20% need antibiotics |
Azithromycin 3 days if invasive or unwell | |
| Shigella spp
Direct damage to colon with toxins |
1 to 3 days | Raw vegetables |
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Ceftriaxone | |
| Enterohemorrhagic E. coli
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1 to 8 days | Ground beef and other meat, fresh produce, unpasteurized milk and juice |
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| Yersinia spp | 4 to 6 days | Pork or pork products, untreated water |
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| Vibrio parahemolyticus | 1 to 3 days | Raw seafood and shellfish |
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| Entamoeba histolytica | 1 to 3 weeks | Fecally contaminated food or water |
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| Others | CMV | Test by serology - viral load in blood
Endoscopy - patchy mucosal erythema in the colon, with inclusion bodies seen on biopsy, which are pathognomic for CMV. Supportive treatment with addition of ganciclovir. |
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| Typhlitis | Neutropaenic enterocolitis | Day 10-14 post chemotherapy
Can occur in any myelosuppressed or immunosuppressed patients |
Affects caecum, adjoining ileum and ascending colon. Watery or bloody diarrhoea in only half of patients. | Operate if peritonitis, free gas, persistent bleeding (resect entire involved segment, regardless of how normal the serosa looks, and do not anastomose).
Tazocin until recovery from neutropaenia and resolution of symptoms, bowel rest, consider NGT, stool spec. Consider G-CSF for severely neutropaenic and unwell patients, however controversial. |
Workup of acute diarrhoea in resource-rich settings
[edit | edit source]- Consider admission if:
- Persistent fever
- Dysentery
- Severe abdominal pain
- Symptoms of volume depletion
- History IBD
- Immunosuppression
- Significant vascular/cardiovascular disease
- History
- Exposures - food history, residence, occupational exposure, recent and remote travel, pets, hobbies
- Recent Abx
- Cirrhosis - vibrio infection
- Haemochromatosis - Yersinia
- Investigations
- Low platelets - concern for development of haemolytic-uraemic syndrome
- Leukemoid reaction - occurs with C. dif
- Indications for stool tests (test those who probably have bacterial infection, since viral will be self-limiting)
- Severe illness (need for hospitalisation)
- Inflammatory diarrhoea (blood, fever)
- High-risk host features
- Symptoms persisting for more than a week
- Public health concerns
- Indications for imaging:
- Abdominal signs
- Unwell patient
- Consider typhlitis or ischaemic colitis
- Choice of test
- Bloody diarrhoea - shiga toxin
- Stool culture is the main one in acute presentations to ED
- Stool culture not very useful for diarrhoea that starts as an inpatient - need CDT
- Ova and parasite testing is only worthwhile for persistent/chronic diarrhoea
- Immunocompromised - CMV (may need endoscopy and biopsy), consider parasites in immunocompromised patients. CMV quantitative serology seems to be recommended.
- MSM - consider proctitis (gonorrhoea, chlamydia, syphilis, HSV)
Management
[edit | edit source]- Simple things
- Fluid replenishment - preferably by oral route - use oral rehydration solutions once initial resuscitation is complete
- Continue eating, avoiding fats and dairy
- Antibiotics indications
- Severe disease
- Sepsis
- Dysentery
- Frail/comorbid host
- Recent international travel
- Pregnant - Listeria therapy
- Haemolytic-uraemic syndrome
- A complication of STEC infection, probably caused by circulating Shiga-toxin
- Defined as nonimmune-mediated haemolytic anaemia (Hct<0.3), thrombocytopaenia (PLT < 150), and any AKI
- Caused by a subset of STEC serogroups, varying with geography
- Less frequent among adults
- Usually first meet diagnostic criteria on about day 7 of illness (range day 5-13)
- Antibiotics can precipitate HUS in STEC infections, so may be worth withholding until this has been excluded in a well patient with high likelihood of STEC (dysentery in afebrile patient, or setting of an outbreak)
- Loperamide can be used cautiously in well patients with no fever and non-bloody diarrhoea