Key facts:
Authors: Natalie Acors and Jayne Eaden
Top Tip: gastroenteritis can be a mild self-limiting disease. But some cases (including C Diff) can be life-threatening
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Key Differential
Diagnoses
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Inflammatory colitis
Ischaemic colitis (AF, elderly, ill, pain)
Colonic carcinoma/diverticular disease
'Complicated gastroenteritis'
= Haemolytic-Uraemic Syndrome (eg O157 E Coli), or causing DIC
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Key Investigations
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FBC, CRP
U+E, LFT, Bone, Glucose
BC, Stool culture (?C diff)
AXR
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Key Treatment
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IV fluids
± PO METRONIDAZOLE 800 mg stat, then 400 mg tds, for 7-10d (C diff)
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Key Management
Decisions
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Admit/not
Antibiotics (not usually necessary; use if C diff)
Steroids ± surgery (C diff)
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Background
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Introduction
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• Onset usually rapid (vs inflammatory colitis). Not necessarily associated with fever. Usually self-limiting, requiring supportive care only
• Some pathogens extremely infectious, virulent, and can cause life-threatening disease
• Clostridium difficile ('C Diff'), often follows antibiotics, and can cause pseudomembranous colitis and present as bloody diarrhoea (like colitis). It has been associated with almost all AB, except aminoglycosides
• For C Diff, quinolones are probably the worse culprits. It can be complicated by toxic megacolon (high mortality) and perforation (very high)
• Prognosis is good in mild cases; but mortality of C diff = 5-10%, 50% severe cases; 5% need surgery (operative mortality 30%). If suspect C diff on admission, and unwell, ask for early senior surgical review
• Ischaemic colitis (elderly, AF) can be missed, with fatal consequences
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Definition
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Inflammation due to infection of lining of GI tract
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| C difficile causing pseudomembranous colitis |
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Risk factors
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Children
Elderly
Immunosuppressed
Recent antibiotics
Food workers
Schools/institutions/hospitals (outbreaks)
Note: food poisoning is a notifiable disease in the UK
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Organisms/causes
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Bacterial
Salmonella (epidemics, eg from poultry; typhi/paratyphi = 'typhoid/paratyphoid fever')
Clostridium sp:
Difficile (recent antibiotics)
Botulinum (processed food; paralysis)
Perfringens (meat)
Campylobacter (poultry; can precipitate Guillain Barre/Reiter's Syndromes)
Staphylococcus aureus (meat)
Bacillus cereus (rice)
Vibrio parahaemolytica (raw seafood)/vibrio cholerae ('cholera')
E Coli (eg O157, from meat/burgers; epidemics; can precipitate HUS/ARF etc)
Shigella (any food)
Cryptosporidium (HIV)
Viral:
Norovirus (hospital outbreaks; vomiting+; 'winter vomiting illness')
Protozoal:
Giardia, amoeba
Chemical toxins:
Mushrooms, garden flora
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Symptoms
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Diarrhoea (can be bloody)/vomiting/anorexia
Abdominal pain
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Key questions
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"When was your last normal motion?"
"Have you had any antibiotics recently?"
"Have you had contact with anyone with gastroenteritis recently (fellow diners)?"
Ask about recent corporate/scoial functions, swimming, canoeing, foreign travel etc
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Signs
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None, or
Fever
Of severe sepsis/shock
Peritonitis (guarding etc), if perforated
Rectal examination is mandatory
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Investigation
Mild acute gastroenteritis does not necessarily need investigation; stool culture only, if relevant
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Blood
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FBC; low Hb or low platelets, think ?DIC or ?Haemolytic-Uraemic Syndrome (eg O157 E Coli?), CRP
U+E (hyper/hyponatraemia? hypokalaemia?), LFT, Bone, Glucose
± TFT
BC
Stool culture (incl C diff)
ABG, if unwell; metabolic acidosis (diarrhoea); alkalosis (vomiting)
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Other
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ECG (AF?)
CXR (erect; perforation?)
AXR (toxic megacolon?)
Flexible sigmoidoscopy if symptoms not resolving
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Key investigation
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Stool culture (+ C diff)
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Specialist investigation
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CT abdomen (alternative diagnoses eg diverticular disease or carcinoma)
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Differential diagnoses
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Inflammatory colitis
Ischaemic colitis (elderly, AF, arteriopath, very ill); operate immediately, if suspect diagnosis
Colonic carcinoma/Diverticular disease
'Complicated gastroenteritis' eg Haemolytic-Uraemic Syndrome (O157 E Coli) or causing DIC
Constipation, with overflow (frail elderly)
Rarely: Carcinoid syndrome
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Treatment
Mild acute gastroenteritis does not require admission, or any treatment; it is a self-limiting disease
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Treatment
(first line)
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Drugs
Nil (supportive)
Note: antibiotics only if unwell, immunosuppressed, frail elderly or certain organisms; resistance is common
± PO METRONIDAZOLE 800 mg stat, then 400 mg tds, for 7-10d (C diff)
± PO CIPROFLOXACIN 500 mg bd (salmonella)
If possible, avoid antidiarrhoeals; esp in C diff (danger of toxic megacolon); if necessary PO loperamide 4mg od stat, then 2mg after each loose stool
Give laxatives in overflow diarrhoea (common in elderly)
Procedures
IV (+fluids, if dry)
Note: if you are not giving iv fluids, why are you admitting them?; ie oral fluids at home may be appropriate
Manage in sideroom
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| Best treatment for mild cases |
 Best treatment for simple mild cases: clear fluids and rest |
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Key management decisions
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Antibiotics/not
(If C diff) steroids ± surgery/not
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Stop
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Antibiotic, if cause
Laxatives (a lot of elderly take these)
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Treatment
(second line)
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Drugs
PO VANCOMYCIN 125 mg qds (C diff) for 7-10d
± PO PREDNISOLONE 20-40 mg od/IV METHYLPREDNISOLONE 500 mg od (C diff)
Procedures:
If ischaemic colitis, operate immediately
If unwell, urinary catheter, CVP, arterial line
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| Prescribing issues |
Antidiarrhoeals may increase chance of toxic megacolon in C diff |
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Admit?
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Usually (if case was mild, probably would not have come to hospital)
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Bed plan
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Medical admission ward
± Gastroenterology, if not better in 48h, or suspect inflammatory colitis
Gen surgery (ischaemic colitis, carcinoma, diverticular disease)
± ITU
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Referrals
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Medical:
Gastroenterology
Microbiology
± Gen surgery
± ITU
Other:
Infection control nurse (esp if think food poisoning, c diff, or viral outbreak in hospital)
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The Rest
| Maxim |
"If you don't put your finger in it, you will put your foot in it" |
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Complications
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Bowel perforation
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Follow-up
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None
Though some diseases our notifiable:
Cholera
Dysentery (Shigella, Campylobacter, E Coli 0157, Salmonella, Balantidiasis, Entamoeba histolytica)
Food poisoning (Toxins/infection)
Treatment of other family members in Giardia
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Prognosis
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Prognosis is good in mild cases; but mortality of C diff = 5-10%, 50% severe cases; 5% need surgery (operative mortality 30%)
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Risk stratification
(who can be managed as outpatient)
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If not unwell, and maintain oral fluids at home; patient does not need admitting, or AB
If moderately unwell, admit, but do not necessarily give AB
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2° Prevention
+ Health promotion
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Don't prescribe unecessary courses AB (especially in elderly); if you do, make courses short, then review efficacy of AB early
Food hygiene
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Don't forget
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• Rectal examination is mandatory
• Ischaemic colitis (especially in elderly in AF)
• Send stool off for C diff
• Chase stool culture for C diff, 24h later
• Report food poisoning (notifiable disease)
• Haemolytic-Uraemic Syndrome
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Red flags
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• Toxic megacolon
• Severe sepsis/shock
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References
